| MISSION_DESCRIPTION |
TABLE OF CONTENTS
----------------------------------
= ROSETTA Mission Overview
= ROSETTA Mission Objectives
- Science Objectives
= Mission Profile
= Mission Phases Overview
- Mission Phase Schedule
- Solar Conjunctions/Oppositions
- Payload Checkouts
= Mission Phases Description
- Launch phase (LEOP)
- Commissioning phase
- Cruise phase 1
- Earth swing-by 1
- Cruise phase 2 (and Deep Impact)
- Mars swing-by
- Cruise phase 3
- Earth swing-by 2
- Cruise phase 4 (splitted in 4-1 and 4-2)
- Steins flyby
- Earth swing-by 3
- Cruise phase 5
- Lutetia flyby
- Rendez-Vous Manoeuver 1
- Cruise phase 6
- Rendez-Vous Manoeuver 2
- Near comet drift (NCD) phase
- Approach phase
- Lander delivery and relay phase
- Escort phase
- Near perihelion phase
- Extended mission
= Orbiter Experiments
- ALICE
- CONSERT
- COSIMA
- GIADA
- MIDAS
- MIRO
- OSIRIS
- ROSINA
- RPC
- RSI
- VIRTIS
- SREM
= LANDER (PHILAE)
- Science Objectives
- Lander Experiments
= Ground Segment
- Rosetta Ground Segment
- Rosetta Science Operations Center
- Rosetta Mission Operations Center
- Rosetta Lander Ground Segment
- Lander Control Center
- Science Operations and Navigation Center
- Rosetta Scientific Data Archive
= Acronyms
ROSETTA Mission Overview
=====================================================================
The ROSETTA mission is an interplanetary mission whose main
objectives are the rendezvous and in-situ measurements of the comet
67P/Churyumov-Gerasimenko, scheduled for 2014/2015. The spacecraft
carries a Rosetta Lander, named Philae, to the nucleus and deploys it
onto its surface.
A brief description of the mission and its objectives can be found in
[GLASSMEIERETAL2007A]. A detailed description of the mission analysis
can be found in the ROSETTA User Manual [RO-DSS-MA-1001], and the
flight Operations Plan [RO-ESC-PL-5000].
On its long way to the comet nucleus after a Launch by Ariane 5 P1+
in March 2004, the ROSETTA spacecraft orbited the Sun for one year
until it returned to Earth for the first swing-by. The planet Mars was
reached in February 2007, about 3 years after launch. In November
2007 a second Earth swing-by took place and a third one in November
2009. Two asteroid flybys (2867 Steins and 21 Lutetia) were performed
on the way to the comet. These two asteroids had been selected at the
Science Working Team meeting on 11th March 2004 among all the
available candidate asteroids, depending on the scientific interest
and the propellant required for the correction manoeuvre. Around the
aphelion of its orbit, which is 5.3 AU from the Sun, the spacecraft
has been in a spinning hibernation mode for about 2.5 years.
Rosetta rendezvoused with comet 67P/Churyumov-Gerasimenko in August
2014. The Philae lander was deployed to the surface of the comet on 12
November 2014.
The end of the nominal mission is planned in December 2015.
The mission has been extended to 30th September 2016.
The Mission Phase Schedule can be found below based on the official
mission calendar. For archive purpose, we used a slightly updated
calendar splitting the escort and extension phases.
Below we summarise the phases used by the team for archive purpose:
MISSION_PHASE_NAME | Abbn | Start date | End date |
--------------------------------------------------------------
'GROUND' | GRND | *** | 2019-09-30 |
'LAUNCH' | LEOP | 2004-03-03 | 2004-03-04 |
'COMMISSIONING 1' | CVP1 | 2004-03-05 | 2004-06-06 |
'CRUISE 1' | CR1 | 2004-06-07 | 2004-09-05 |
'COMMISSIONING 2' | CVP2 | 2004-09-06 | 2004-10-16 |
'EARTH SWING-BY 1' | EAR1 | 2004-10-17 | 2005-04-04 |
'CRUISE 2' | CR2 | 2005-04-05 | 2006-07-28 |
'MARS SWING-BY ' | MARS | 2006-07-29 | 2007-05-28 |
'CRUISE 3' | CR3 | 2007-05-29 | 2007-09-12 |
'EARTH SWING-BY 2' | EAR2 | 2007-09-13 | 2008-01-27 |
'CRUISE 4-1' | CR4A | 2008-01-28 | 2008-08-03 |
'STEINS FLY-BY' | AST1 | 2008-08-04 | 2008-10-05 |
'CRUISE 4-2' | CR4B | 2008-10-06 | 2009-09-13 |
'EARTH SWING-BY 3' | EAR3 | 2009-09-14 | 2009-12-13 |
'CRUISE 5' | CR5 | 2009-12-14 | 2010-05-16 |
'LUTETIA FLY-BY' | AST2 | 2010-05-17 | 2010-09-03 |
'RENDEZVOUS MANOEUVRE 1' | RVM1 | 2010-09-04 | 2011-06-07 |
'CRUISE 6' | CR6 | 2011-06-08 | 2014-01-20 |
'PRELANDING' | PRL | 2014-01-21 | 2014-11-19 |
'COMET ESCORT 1' | ESC1 | 2014-11-20 | 2015-03-10 |
'COMET ESCORT 2' | ESC2 | 2015-03-11 | 2015-06-30 |
'COMET ESCORT 3' | ESC3 | 2015-07-01 | 2015-10-21 |
'COMET ESCORT 4' | ESC4 | 2015-10-22 | 2015-12-31 |
ROSETTA EXTENSION 1 | EXT1 | 2016-01-01 | 2016-04-05 |
ROSETTA EXTENSION 2 | EXT2 | 2016-04-06 | 2016-06-30 |
ROSETTA EXTENSION 3 | EXT3 | 2016-07-01 | 2016-09-30 |
--------------------------------------------------------------
For the Lander, the Cruise Phase data sets followed the same
filenaming but the Comet phase has been split differently:
MISSION_PHASE_NAME | Abbn| Start date | End date |
----------------------------------------------------------------------
'POST HIBERNATION | PHC | 2014-04-09T08:15:25 | 2014-04-23T15:45:13 |
COMMISSIONING' | | | |
----------------------------------------------------------------------
'PRE DELIVERY | PDCS| 2014-07-13T14:42:56 | 2014-10-17T20:31:20 |
CALIB SCIENCE' | | | |
----------------------------------------------------------------------
'SEPARATION DESCENT| SDL | 2014-11-12T08:35:02 | 2014-11-12T15:34:04 |
LANDING' | | | |
----------------------------------------------------------------------
'REBOUNDS' | RBD | 2014-11-12T15:34:05 | 2014-11-12T17:30:20 |
----------------------------------------------------------------------
'FIRST SCIENCE | FSS | 2014-11-12T17:30:21 | 2014-11-15T01:00:00 |
SEQUENCE' | | | |
----------------------------------------------------------------------
Please note:
------------
The ROSETTA spacecraft was originally designed for a mission to the
comet 46 P/Wirtanen to be launched in January 2003. Due to a delay of
the launch a new comet (67P/Churyumov-Gerasimenko) had been selected
by the Science Working Team on 3rd-4th April 2003.
The compliance of the design was checked and where necessary adapted
for this new mission. Therefore in the following all the details and
characteristics for this new mission are used.
ROSETTA Mission Objectives
=====================================================================
The scientific objectives of the ROSETTA mission can be considered
from three main viewpoints:
First of all, comets and asteroids are fully-fledged members of our
solar system, which means, that they are objects of intrinsic
interest to planetary scientists. The level of investigations
conducted on these bodies is therefore far below that achieved for
the other objects of the solar system.
The study of the small solar-system bodies arguably represents the
last major gap in the tremendous worldwide effort that has been made
to reveal our planetary neighbours to us.
The most important scientific rationale for studying small solar-
system bodies is the key role-play in helping us to understand the
formation of the solar system. Comets and asteroids have a close
genetic relationship with the planetesimals, which formed from the
solar nebula 4.57 billion years ago. Most of our present
understanding of these processes has been obtained by studying
meteorites, which constitute a biased sample of asteroidal material,
and micrometeoroids, which may represent cometary grains processed by
solar radiation and atmospheric entry. There is therefore a strong
scientific case of studying cometary material in situ, as it is
surely more primitive than extraterrestrial samples.
A third scientific aspect is the study of the physio-chemical
processes, which are specific to comets and asteroids. In this
respect, asteroids can provide information on impact phenomena,
particularly on very large scale. However, the increase in cometary
activity as these bodies approach the Sun undoubtedly represents one
of the most complex and fascinating processes to be observed in the
solar system.
Science Objectives
---------------------
The prime scientific objectives as defined in the Announcement of
Opportunity [RO-EST-AO-0001] by the Rosetta Science Team can be
summarized as:
- Global characterisation of the nucleus, determination of dynamic
properties, surface morphology and composition
- Chemical, mineralogical and isotropic compositions of volatiles and
refractories in a cometary nucleus
- Physical properties and interrelation of volatiles and refractories
in a cometary nucleus
- Study of the development of cometary activity and the processes in
the surface layer of the nucleus and in the inner coma (dust-gas
interaction)
- Origin of comets, relationship between cometary and interstellar
material.
- Implications for the origin of the solar system
- Global characterisation of the asteroid, determination of dynamic
properties, surface morphology and composition.
Mission Profile
=====================================================================
The ROSETTA mission profile results from the orbit of the target
comet 67P/Churyumov-Gerasimenko, which has a perihelion close to 1.2
AU and an aphelion of about 5.7 AU, resulting in a period of about
6.5 years. A detailed description of the Mission Profile can be found
in the Rosetta Mission Calendar [RO-ESC-PL-5026] and in the RSOC
Design Specification [RO-EST-PL-2010].
The injection of the spacecraft by a single Ariane 5 Launch with the
so-called 'delayed ignition' of the upper stage, was not directly into
the trajectory to the comet, because of the high spacecraft wet mass.
Therefore the spacecraft had to be accelerated by a sequence of
gravity assist manoeuvres at Mars and the Earth, in order to catch up
with the comet's velocity at perihelion.
The initially large distance to the comet at the perihelion of its
trajectory has been slowly decreasing after the third Earth swing-by.
At the intersection of both orbits, the difference in orbit
inclination and the residual relative velocity were diminished by the
comet orbit matching manoeuvre at around 4.0 AU Sun distance. The
range of the spacecraft-to-Sun distance was between 0.88 and 5.33 AU,
defined by the minimum Sun distance during the first five years of the
mission with the swing-bys at Earth, and the maximum Sun distance
close to the aphelion of the comet's orbit. The evolution of the
spacecraft distance to Earth over the mission time followed the
profile of the Sun distance superimposed by an oscillation with an
amplitude of 2 AU (+1,-1) and a period of about one year due to the
Earth's motion around the Sun. This resulted in a range from 0 AU
(Earth Departure and Swing-by) to 6.3 AU during the superior solar
conjunction close to the spacecraft's aphelion (see Solar Conjunctions
section below).
After the second and third Earth swing-by ROSETTA crossed the
asteroid main belt, which gave the opportunity of two asteroid flybys.
The asteroids 2867 Steins and 21 Lutetia, were encountered on
5 September 2008 and 10 July 2010 respectively. These two asteroids
had been selected at the Science Working Team meeting on 11th March
2004 among all the available candidate asteroids, depending on the
scientific interests and the propellant required for the correction
manoeuvre.
Between the major mission events, up to the comet rendezvous
manoeuvre, the spacecraft performed long interplanetary cruise phases
(up to 2.5 years) with several solar conjunctions (see Solar
Conjunctions section below) and the power critical aphelion passage
(last cruise phase). In order to reduce the ground segment costs and
the wear and tear of spacecraft equipment during these phases, the
spacecraft was put in 'Hibernation Mode'.
Two types of hibernation modes were planned to be used:
* 'Deep Space Hibernation Mode' above 4.5 AU: Inertial spin mode with
a spin rate of 4 deg/sec. The spacecraft was almost entirely passive,
except of receivers/ decoders, power supply, heaters and two
Processor Modules with one RTU.
* 'Near Sun Hibernation Mode' below 4.5 AU: 3-axes stabilised mode
with the solar arrays Sun-pointing and the +X-axis Earth-pointing.
Attitude control was performed with thrusters and star trackers, based
on ephemerides; occasional solar array adjustments and ground
contacts via the medium gain antenna (MGA).
The final approach to the comet into its sphere of influence was
prepared by the rendezvous manoeuvre (RVM-2), that matched the
spacecraft orbit with the comet orbit.
A subsequent sequence of approach manoeuvres, supported by optical
navigation, took the spacecraft closer and closer to the comet.
After determination of the physical model of the comet by Doppler and
optical measurements, the spacecraft was inserted into a global
mapping orbit around the comet.
The 'Duck-shape' of the comet was a surprised and a challenge for the
Flight Dynamics team. Three activity cases had been planned to orbit
the comet, respectively at 30, 20 or 10km. Finally, it has been chosen
to go to 10km.
Meanwhile, a board was selecting 5 and then 2 landing sites. The
chosen landing site were located on the 'head' of the Duck Shape
comet.
The delivery of the Lander or Surface Science Package (SSP) was
achieved from an eccentric orbit, which took the spacecraft to a low
altitude above the selected landing site. The Lander release was fully
automatic according to a predefined schedule, and led to a first touch
down with minimum vertical and horizontal velocities relative to the
local rotating surface.
The first touch down reached the foreseen landing site within 50m
accuracy. However, the Lander did not succeed in harpooning and
bounced twice. It was stopped by cliff walls, which unluckily hid the
Lander from the Sun.
The Lander, Philae, had the time to operate all instruments on board,
during a phase named the FSS, First Science Sequence, before going to
sleep on November, 15th at 00:36 UTC. Upon the landing of the Lander,
the spacecraft provided uplink and downlink data relay between the
Lander and the Earth.
After the Lander delivery the ROSETTA spacecraft escorted the comet
until the perihelion passage (13th August 2015) and outwards again,
until a Sun distance of 2 AU was reached at end of the year 2015.
The main scientific objective during this phase was the monitoring of
the features of the active comet.
The mission was extended from 1st January 2016 to 30th September 2016.
Rosetta ended its journey on September 30th by a controlled impact
onto the comet from a altitude of about 19km.
Mission Phases Overview
======================================================================
This section gives an overview of the major mission phases and main
events in scheduled tables. A description of the individual phases is
given in the following section. More detailed information can be
found in the Rosetta Mission Calendar [RO-ESC-PL-5026] and the RSOC
Design Specification [RO-EST-PL-2010]
Mission Phase Schedule
-----------------------
The following table shows a schedule of the mission phases, with
start-end times (dd/mm/yyyy), duration (days) and distance to the sun
(Astronomical Units). Some of the most important events within the
mission phases are marked with an arrow (->). Further description of
each mission phase is given below.
.====================================================================
| Phase |Start Date|Main Event| End Date |Dur |SunDist(AU)|
|=================|==========|==========|==========|====|===========|
|LEOP |02/03/2004| |04/03/2004| 3 | |
|-----------------|----------|----------|----------|----|-----------|
|Commissioning1 |05/03/2004| |06/06/2004| 94 | 0.89-0.99 |
| ->DSM1 | |11/05/2004| | | |
| ->DSM1 Touch-up| |16/05/2004| | | |
|-----------------|----------|----------|----------|----|-----------|
|Cruise 1 |07/06/2004| |05/09/2004| 91 | 0.89-1.04 |
|-----------------|----------|----------|----------|----|-----------|
|Commissioning2 |06/09/2004| |16/10/2004| 41 | 1.04-1.09 |
|-----------------|----------|----------|----------|----|-----------|
|Earth Swing-by1 |17/10/2004| |04/04/2005| 170| 0.99-1.11 |
| ->Earth | |04/03/2005| | | |
|-----------------|----------|----------|----------|----|-----------|
|Cruise 2 |05/04/2005| |28/07/2006| 480| 1.04-1.76 |
| ->Deep Impact | |04/07/2005| | | |
|-----------------|----------|----------|----------|----|-----------|
|Mars Swing-by |29/07/2006| |28/05/2007| 304| 0.99-1.59 |
| ->DSM2 | |29/09/2006| | | |
| ->Mars | |25/02/2007| | | |
| ->DSM3 | |29/04/2007| | | |
|-----------------|----------|----------|----------|----|-----------|
|Cruise 3 |29/05/2007| |12/09/2007| 107| 1.32-1.58 |
|-----------------|----------|----------|----------|----|-----------|
|Earth Swing-by2 |13/09/2007| |27/01/2008| 137| 0.91-1.32 |
| ->Earth | |13/11/2007| | | |
|-----------------|----------|----------|----------|----|-----------|
|Cruise 4-1 |28/01/2008| |03/08/2008| 189| 1.02-2.03 |
|-----------------|----------|----------|----------|----|-----------|
|Steins Flyby |04/08/2008| |05/10/2008| 63 | 2.03-2.19 |
| ->Steins | |05/09/2008| | | |
|-----------------|----------|----------|----------|----|-----------|
|Cruise 4-2 |06/10/2008| |13/09/2009| 343| 1.35-2.26 |
| ->DSM4 | |19/03/2009| | | |
|-----------------|----------|----------|----------|----|-----------|
|Earth Swing-by3 |14/09/2009| |13/12/2009| 92 | 0.98-1.35 |
| ->Earth | |13/11/2009| | | |
|-----------------|----------|----------|----------|----|-----------|
|Cruise 5 |14/12/2009| |16/05/2010| 154| 1.03-2.45 |
|-----------------|----------|----------|----------|----|-----------|
|Lutetia Flyby |17/05/2010| |03/09/2010| 111| 2.45-3.14 |
| ->Lutetia | |10/07/2010| | | |
|-----------------|----------|----------|----------|----|-----------|
|Rendez-vousMan1 |04/09/2010| |13/07/2011| 313| 3.15-4.58 |
| ->RVM1 | |23/01/2011| | | |
|-----------------|----------|----------|----------|----|-----------|
|Cruise 6 (DSHM) |14/07/2011| |20/01/2014| 917| 4.46-5.29 |
|-----------------|----------|----------|----------|----|-----------|
|Rendez-vousMan2 |21/01/2014| |17/08/2014| 206| 3.40-4.49 |
| ->RVM2 1st burn | |21/05/2014| | | |
|-----------------|----------|----------|----------|----|-----------|
|Global Mapping |18/08/2014| |19/10/2014| 63 | 3.15-3.53 |
|and Close | | | | | |
|Observation | | | | | |
|-----------------|----------|----------|----------|----|-----------|
|Lander Delivery |20/10/2014| |16/11/2014| 28 | 2.97-3.15 |
|->Lander Delivery| |12/11/2014| | | |
|-----------------|----------|----------|----------|----|-----------|
|Comet Escort |17/11/2014| |31/12/2015| 410| 1.24-2.96 |
'-------------------------------------------------------------------'
| Extension |31/12/2015| |30/09/2016| 274| 2.01-3.83 |
'-------------------------------------------------------------------'
Payload Checkouts
-----------------
Payload checkouts were scenarios designed to allow Rosetta payload to
make regular health checks, to activate mechanisms and to monitor
trends through calibration tests. They were allocated in the mission
calendar at regular 6-month periods during the first 10 years of the
mission cruise phase. They were split into passive and active payload
checkouts. Passive payload checkouts were entirely non-interactive.
Conditions for the passive checkout were that it would:
a) not require any real time monitoring, b) run entirely off of MTL,
c) not require s/c specific pointing other than to maintain listed
constraints, d) produce minimal science data. Active payload checkout
operations were executed both interactively and non-interactively .
Conditions for the active checkout were that it would: a) limit the
requirement for real time monitoring, b) run mostly from MTL, c) limit
the requirement for s/c specific pointing beyond maintaining listed
constraints, d) produce minimal science data. There was more
flexibility during active checkouts and in addition payloads used
interactive passes to make any necessary memory patches and tests.
.-------------------------------------------------------------------.
| Name | Type | Begin | End | Mission Phase |
|-----------------|--------|----------|-----------|-----------------|
| P/L Checkout 0 |Passive |27/03/2005| 31/03/2005| Earth Swing-by 1|
| P/L Checkout 1 |Passive |30/09/2005| 05/10/2005| Cruise 2 |
| P/L Checkout 2 |Passive |03/03/2006| 08/03/2006| Cruise 2 |
| P/L Checkout 3 |Passive |25/08/2006| 30/08/2006| Mars Swing-by |
| P/L Checkout 4 | Active |23/11/2006| 22/12/2006| Mars Swing-by |
| P/L Checkout 5 |Passive |18/05/2007| 23/05/2007| Mars Swing-by |
| P/L Checkout 6 | Active |13/09/2007| 29/09/2007| Earth Swing-by 2|
| P/L Checkout 7 |Passive |04/01/2008| 09/01/2008| Earth Swing-by 2|
| P/L Checkout 8 | Active |19/07/2008| 24/07/2008| Cruise 4-1 |
| P/L Checkout 9 |Passive |28/01/2009| 02/02/2009| Cruise 4-2 |
| P/L Checkout 10 | Active |18/09/2009| 08/10/2009| Earth Swing-by 3|
| P/L Checkout 12 |Passive |22/04/2010| 15/05/2010| Cruise 5 |
| P/L Checkout 13 |Passive |01/12/2010| 15/12/2010| RVM1 |
'-------------------------------------------------------------------'
Solar Conjunctions/Oppositions
-------------------------------
Other mission phases, which resulted from the orbit geometry and
interfered with the above operational phases, were the solar
conjunctions.
Two types of conjunctions occurred throughout the mission:
* Solar Oppositions: The Earth was between spacecraft and Sun,
resulting in a degradation of the command link to the spacecraft.
* Superior Solar Conjunctions: Sun was between spacecraft and Earth,
resulting in a degradation of the command and telemetry link to/from
the spacecraft.
Table below shows the solar conjunction phases throughout the mission
with type, begin and duration of the conjunction and corresponding
mission phase. The phases are defined as the periods, during which
the Sun-SpaceCraft-Earth (SSCE) angle is below 5 degrees.
.-------------------------------------------------------------------.
| Type |Duration| Begin | End | Mission Phase |
|---------------|--------|------------|------------|----------------|
| Conjunction 1 | 48d | 21/03/2006 | 07/05/2006 | Cruise 2 |
| Conjunction 2 | 39d | 08/12/2008 | 15/01/2009 | Cruise 4-2 |
| Conjunction 3 | 50d | 22/09/2010 | 10/11/2010 | RV Manoeuver 1 |
| Opposition 1 | 37d | 13/04/2011 | 19/05/2011 | RV Manoeuver 1 |
| Conjunction 4 | 64d | 15/10/2011 | 17/12/2011 | Cruise 6 |
| Opposition 2 | 47d | 30/04/2012 | 15/06/2012 | Cruise 6 |
| Conjunction 5 | 67d | 31/10/2012 | 05/01/2013 | Cruise 6 |
| Opposition 3 | 46d | 20/05/2013 | 04/07/2013 | Cruise 6 |
| Conjunction 6 | 60d | 24/11/2013 | 22/01/2014 | Cruise 6 |
| Opposition 4 | 28d | 25/06/2014 | 22/07/2014 | RV Manoeuver 2 |
| Conjunction 7 | 41d | 21/01/2015 | 02/03/2015 | Comet Escort |
'--------------------------------------------------------------------
It can be noted that for archive purpose and because of the non
expected landing, which included rebounds, the Lander team provided
the data sets from wake up up to the First Science Sequence (FSS) in 5
data sets with sub mission phases that differ from the official ones.
The table below lists these sub phases:
----------------------------------------------------------------------
| PHC | Post Hibernation | 2014-04-09T08:15:25 | 2014-04-23T15:45:13|
| | Commissioning | | |
|------|------------------|---------------------|--------------------|
| PDCS | Pre Delivery | 2014-07-13T14:42:56 | 2014-10-17T20:31:20|
| | Calib Science | | |
|------|------------------|---------------------|--------------------|
| SDL | Separation | 2014-11-12T08:35:02 | 2014-11-12T15:34:04|
| | Descent Landing | | |
|------|------------------|---------------------|--------------------|
| RBD | Rebounds | 2014-11-12T15:34:05 | 2014-11-12T17:30:20|
|------|------------------|---------------------|--------------------|
| FSS | First Science | 2014-11-12T17:30:21 | 2014-11-15T01:00:00|
| | Sequence | | |
----------------------------------------------------------------------
The Orbiter instruments use the phase Prelanding (PRL) to deliver the
data from wake-up to FSS.
Mission Phases Description
=====================================================================
Launch and Early Orbit Phase (LEOP)
-----------------------------
Rosetta was launched by an Ariane 5/G+ in a dedicated flight (single
launch configuration) from Kourou at 07:17:51 UTC 2 March 2004. After
burnout of the lower composite, the upper stage together with the
spacecraft remained in an eccentric coast arc for nearly 2 hours.
Then the upper stage performed delayed ignition and injected the
Rosetta spacecraft into the required escape hyperbola.
After spacecraft separation from the upper stage, Rosetta acquired
its three axes stabilised Sun pointing attitude and deployed the solar
arrays autonomously. Ground operations acquired the down-link in
S-band using the ESA network and controlled the spacecraft to a fine-
pointing attitude with the HGA pointing towards Earth using X-band
telemetry. Tracking and orbit determination were performed, the
departure trajectory was verified and corrected by the on-board
propulsion system of the spacecraft.
The launch locks of the Lander Philae were released at the end of the
first ground station pass. Philae remained firmly attached to the
spacecraft by the cruise latches until its release at the comet.
Commissioning phase (1 and 2)
-------------------
Commissioning started three days after launch following the first
trajectory correction manoeuvre. A Deep Space Manoeuver (DSM1) of 173
m/s was executed at perihelion. All spacecraft functions needed during
the cruise to the comet, in particular for hibernation, were checked
and the scientific payload was commissioned.
Commissioning was done in two parts, as the New Norcia ground station
must have been shared with Mars Express and could not be used
by Rosetta from June to mid-September 2004.
For more information refer to the following reports:
[RO-EST-RP-3293] Consolidated Rosetta Payload Report of the Mission
Commissioning Results Review
[RO-EST-RP-3307] RSOC_Commissioning_Results_Report_2005Dec19.pdf
[RO-EST-RP-3343] Interference Scenario Report
Cruise phase 1
--------------
Almost all the scientific instruments, except ALICE were switched off
while ground contact was practically not available. No payload
operations were done during this phase.
Earth swing-by 1
----------------
The actual Earth swing-by took place on 4-Mar-05. The phase ended one
month after the swing-by and the spacecraft was prepared for the next
cruise phase to Mars.
One passive Payload Checkout was scheduled end of March 2005.
Immediately after this flyby an Asteroid Flyby Mode Simulation was
performed using the Moon as a target. Some limited payload operations
were permitted shortly before during and shortly after this Earth
Flyby. Rosetta payload teams were given the opportunity to conduct
scientific investigation that included close approach of both the
Earth and the Moon and the AFM simulation. Any activities that did not
require the Earth-Moon system i.e. continued instrument commissioning,
were considered for later in the Mission, such as during the next
active checkout.
The instrument objectives are listed below.
ORBITER
ALICE
- Flat field calibration
- Extended object scattered light calibration (Moon as the target)
- Absolute solar calibration
- Absolute flux and wavelength calibration (wide part of the slit
to take in the Moon)
- Door performance test due to anomalies raised during
commissioning
MIRO
- Asteroid Flyby Simulation test
- H2O lines in Earth (high quality data obtained but analysis not
complete)
- Radiometric calibration of the Moon
RPC
- Sensor calibration
- Magnetospheric physics
- Verification of the science operations modes for the Mars flyby
RSI
- HGA to Earth around closest approach to Moon
OSIRIS
- Because of technical issues OSIRIS was not operated during the
Earth Swing-By itself.
VIRTIS
- Co-alignment M/H
- Aldebaran target in IR (failed, boresight did not detect the
target)
- Absolute calibration using the Moon
- Full disc Earth imaging including exosphere over one rotation
LANDER
CIVA
- Earth Picture with Camera #2 or 4
ROMAP with RPC MAG
- magnetic axes alignment of sensors with Earth magnetic field
- Checking of scaled values with known Earth values
- Solar wind values comparison with other s/c
Problems:
RPC
- Loss of LAP science data for 41.5 hours (2005-03-01 19:00 --
2005-04-03 12:30).
For more information refer to the following reports:
[RO-EST-RP-3318] Payload Passive Checkout 0 Report
[RO-EST-RP-3321] Rosetta Earth-Swingby #1 Payload Operations Report
Cruise phase 2 (and Deep Impact)
--------------------------------
After leaving the Earth, the spacecraft made one revolution around the
Sun, and in the second arc from perihelion to aphelion made a swing-by
of Mars.
There was a solar conjunction for more than one month in April 2006
(see Solar Conjunctions section above). Two passive check-outs with
non-interactive instrument operations for about 5 days were scheduled
during the cruise to Mars. PC1 occurred from 5/09/2005 to 5/10/2005.
PC2 took place from 3/03/2006 to 8/03/2006.
The NASA Deep Impact mission encountered comet 9P/Tempel 1 on 4 July
2005, which fell into the Cruise 2 mission phase. At around 06:00
UTC, the mother probe sent a 362 kg impactor into the nucleus with a
relative speed of 10.2 km/s. Rosetta was in a privileged position for
its remote sensing instruments to observe the event (80 million km
distance, 90 degrees angle respect to the sun). Rosetta monitored
Tempel 1 continuously (i.e. 24 hrs per day) over an extended period
from 7 days before the deep impact to 11 days afterwards (27Jun-15Jul
2005). The first 2 days ALICE observed the stars for calibration. From
the 28th June to the 15th July, OSIRIS, ALICE, and MIRO operated
observing comet 9P/Tempel 1 continuously. VIRTIS was on only several
hours around the impact. Maintenance activities were carried out for
COSIMA, ROSINA, ALICE.
During the Deep Impact subphase, the instruments had the following
objectives:
ORBITER
ALICE
- Baseline pre-impact spectrum. Comparison with near and long
term post impact spectra. The comet was detected in all spectra.
- Strong atomic lines of neutral H and O were detected throughout
the observation period.
- Two weak lines of neutral C detected on some dates. No change
detected by ALICE in comet's UV spectrum as a result of impact
- except for possible enhancement in C emission.
- No evidence of Ar, S, N, CO.
- Water production rates. Results TBC.
- Dark histograms.
- Calibration star before the encounter. Spectra of calibration
star was used for calibration of the Deep Impact spectra and
instrument sensitivity. The data was also used to look for any
flux variations due to pointing/jitter (initial results did not
show any evidence of significant fluctuations in the stellar
count rate).
- Memory patch (time synchronisation issue).
MIRO
- Changes in the coma composition induced by the impact.
- Upper limit on the water production rate in the pre-impact
phase of the experiment. Water production rate and albeit
with low signal-to-noise measured in the post impact phase. The
water production rate was less than had been anticipated based
on models.
- Detection of carbon monoxide: the analysis was not complete but
so far no CO was detected.
- Estimate of Doppler velocity.
OSIRIS
- Accurate photometry of the unresolved nucleus (no atmosphere in
between) with complete time coverage. The time resolution was
better than a minute around the impact and could draw conclusion
about the evolution of the impact cloud during the first hour.
The long term monitoring allowed determination of the composition
and evolution of the impact cloud (water production and dust/ice
ratio)
- UV coverage that allowed imaging of the OH emission at 308nm
(estimate of the water production by the impact)
- Imaging of the coma out to at least 150000km from the nucleus.
The effect of the impact could be seen in the images for
approximately a week (stereo reconstruction of coma,
impact cloud).
VIRTIS
- Coma and ejecta composition and temporal evolution. But the
outburst due to the impact was not energetic enough to reach the
minimum sensitivity required.
Conclusions of the Deep Impact Observations:
The science objectives of the Deep Impact Observations scenario were
met. The brightness increase of Tempel 1 produced by the impact was
lower than we had hoped for, and as a result the comet was too weak to
be detected by VIRTIS. For ALICE and MIRO the signal was just above
the sensitivity limit, but nevertheless important measurements could
be achieved. The results of OSIRIS even exceeded the expectations, and
the first scientific publications were widely cited. The data
collected by the experiments on board Rosetta are unique because
Tempel 1 was monitored continuously over an extended period of time
(no day-and-night cycle in contrast to ground-based telescopes) and in
the absence of an absorbing atmosphere.
The following operations was done during the Passive checkout 1:
ORBITER
ALICE
- Electronic and software
- Test pattern and stim test
- Memory check
- dark exposures
There was no instrument anomalies. The door performance test
showed nominal behavior.
CONSERT
- Consert Orbiter verification
- Consert Lander verification
- Consert Orbiter/Lander time synchronisation
COSIMA
- Self check
- Target manipulator unit maintenance
- Ion emitter maintenance
GIADA
- Run mechanisms - cover operations
- Health check (all subsystems, electronics, noise and
contamination monitoring, performances estimation)
MIDAS
- Exercising of all mechanisms (shutter, approach mechanism,
linear stage, wheel, scanner)
The test was successful and MIDAS is fully operable.
MIRO
- Regular exercise and health check of all commands in all modes
- Regular dump of EEPROM memory to check for radiation damage.
All objectives were met. There was no radiation damage of the
EEPROM.
RPC
- MAG: instrument calibration. Undisturbed solar wind was measured
to calibrate the offsets of the MAG instrument in quiet conditions
(Hedgecock method).
- LAP: instrument calibration.
- MIP: Instrument checkout
- IES: measurement in the undisturbed solar wind for calibration
of its sensors and cross calibration with LAP.
The PC operations were completed successfully with no change in
instrument performance for MAG and IES.
RSI
Two frequency downlink driven by the USO and a ground station
that could receive the X and S band signals.
- Investigate the stability of the USO
- Verify interaction with the ground
Investigations of the USO data from PC#0 revealed that the
behaviour of the USO was obviously not as good as it had been
during the last USO test in October.
OSIRIS
- Exercise the instrument mechanisms
- Verify the sanity of the CCD
- Verify the focus
No anomaly occurred.
LANDER
Test of the Lander Platform overall performance
Secondary battery monitoring
Lander extended AFT
CDMS EEPROM dump
functional test for
PTOLEMY
CONSERT
The following operations have been done during the Passive checkout 2:
ORBITER
ALICE
- same health tests as PC1. Tests successful.
CONSERT
- same as PC1. Tests generally successful (see report)
COSIMA
- self check of all hardware sub-systems on operational voltage
levels
- target manipulator unit checkout
- maintenance COSISCOPE checkout
- emitter maintenance
Tests generally successful.
GIADA
- Same as PC1 plus monitoring of MBS coating evolution.
The cover operations went fine. There was no further contamination
of the microbalances. GDS is not fully tested for light
conditions. IS seems nominal. All HK values were as expected.
MIDAS
- same as PC1. Tests were successful.
MIRO
- Same as PC1. Overall success.
RPC
- Same as PC1. All performances checked were nominal.
RSI
- Same as PC1. The USO behaved very good, USO drift satisfactory.
OSIRIS
- Same as PC1. Generally successful. For solar elongation
angles < 90 degrees OSIRIS got substantial scattered light
through the nominally closed doors. The scattered light observed
during PC2 was unfortunately enough that parts of the CCD surface
was saturated. This happened in spite of the large exposure time
reduction that was made after PC1.
VIRTIS
- The check done were performed properly.
LANDER
Same as PC1 plus functional tests for
MUPUS
CONSERT
For more information refer to the following reports:
[RO-EST-RP-3341] Deep Impact Observations, Payload Operations Report
[RO-EST-RP-3342] Passive Payload Checkout 1 Report
[RO-EST-RP-3418] Passive Payload Checkout 2 Report
Mars swing-by
-------------
The mission phase began two months before DSM2 of 65 m/s, which was
performed near perihelion. The actual Mars swing-by took place on
25-Feb-07. The minimum altitude with respect to the Martian surface
was 200 km. The relative approach and departure velocity was 8.8 km/s.
During the swing-by a communications black-out of approximately 14
min was expected due to occultation of the spacecraft by Mars.
Furthermore the spacecraft was expected to be in eclipse for about 24
min. The phase ended one month after DSM3. DSM3 of 129 m/s was
scheduled near the aphelion of this arc in order to obtain the proper
arrival conditions at the Earth. Two passive payload check-outs of
about 5 days and an active longer one of 25 days were scheduled during
the phase (PC3, PC4, PC5).
PC3 started on 25th August 2006 and ended 30th August 2006.
The following operations were planed during PC3. GIADA and ROSINA did
not take part in this PC.
ORBITER
ALICE
- Electronics & software verification, test pattern and stim test,
Memory Check, Aperture Door, Performance Test.
All operations are executed as expected.
CONSERT
- Consert Orbiter verification, Consert Lander verification,
Consert Orbiter/Lander time Synchronisation.
COSIMA
- self check of all hardware sub-systems on operational voltage
levels, target manipulator unit checkout and maintenance emitter
maintenance
MIDAS
- Regular health check and exercising of all mechanisms (shutter,
approach mechanism, linear stage, wheel, scanner)
MIRO
- Regular exercise and health check of all commands in all modes.
Regular dump of EEPROM memory to check for radiation damage.
All operations are successful.
RPC
- MAG: Instrument calibration. Undisturbed solar wind measurement.
Such data will be used to calibrate the offsets of the MAG
instrument in quiet conditions (Hedgecock method).
- LAP: Instrument calibration.
- MIP: Instrument checkout.
- IES: measurements in the undisturbed solar wind for calibration
of its sensors and crosscalibration with LAP.
RSI
- Investigate the stability of the USO and verify interaction
with the ground.
The PC3 results were very promising and the behavior of the USO
is as good as expected. The stability of the USO was still one
order of magnitude better than anticipated before launch.
OSIRIS
- Instrument mechanisms, verify the sanity of the CCD, verify the
focus of the instrument.
VIRTIS
- Both VIRTIS M and H were working as expected.
- PC3 was used to verify the upload of a new pixel map for
VIRTIS-H to be used during the forthcoming PC4 (pixel map allowed
to drastically reduce the data volume).
LANDER
- Test of the Lander platform to check the overall performance and
Secondary Battery Status
- Lander Extended AFT with short function
- tests of some units and
EEPROM
- checks for all ComDPU units
- Secondary Battery Monitoring
- CDMS EEPROM dump
- Separate short functional tests for MUPUS and CONSERT
PC4 was an active checkout. It started on Nov., 23rd and ended on
Dec., 22nd 2006. All Rosetta payload instruments took part in this
scenario.
ALICE
- Passive Check out
- Optics Decontamination
- HV and detector tests
- Calibrations, performance
- Stare observations of Saturn and Vega
CONSERT
- Passive 6 months Status Check
NAVCAM
- Calibration
COSIMA
- Maintenance Procedure
- Cosiscope operation
GIADA
- Passive 6 months status check
- Settings test
LANDER
- Lander interactive and non interactive operations
MIDAS
- Check out and mechanism activation
- s/w upload and functional check out
- Calibration
- High resolution image of a dust collector facet
MIRO
- Passive Status Check
ROSINA
- DPU s/w Patch
- COPS microtips
- DFMS cover and modes
- RTOF delta commissioning
RPC
- Passive Check out and calibrations
- IES noisy channels test, upload patches and tables
- LDL failure investigation
- Upload new LAP macros
- MIP new seq test
- Mars Swing By rehearsal
- ROMAP/RPC co operation
- MAG continuous operation
- Upload temporary patch for directional resolution improvement
RSI
- Passive two frequency downlink
SREM
- Continuous operation
OSIRIS
- Passive 6 months Check
- Bias, darks, charge transfer efficiency with doors closed
- Patch s/w
- Staring observations
- Calibration and Mars Fly By preparation
VIRTIS
- H and M calibrations
Although several open issues were resolved in this checkout, several
issues remain open and new anomaly report were generated.
75% of the planned operations were successful. The 25% loss was mainly
due to OSIRIS that lost the majority of its operations.
PC5 is a Passive Check Out that started on May, 18th and ended on May,
23rd 2007. The instruments that took part in this PC are listed below:
ALICE, CONSERT, COSIMA, GIADA, LANDER, MIDAS, MIRO, RPC, RSI, OSIRIS.
VIRTIS was NOGO and did not operate.
Main objectives of the scenario have been met with no issues.
Payload checkout reports:
[RO-SGS-RP-0001]
_Rosetta_Passive_Payload_Checkout_3_Report_2007Jun27.pdf
[RO-EST-RP-3464]
_Rosetta_Report_Active_Payload_Checkout_4_2006Apr13.pdf
[RO-SGS-RP-0002]
_Rosetta_Passive_Payload_Checkout_5_Report_2007June27.pdf
Cruise phase 3
--------------
No check-outs were scheduled during the short cruise to Earth.
Earth swing-by 2
----------------
Daily operations started again around two months before Rosetta
reached Earth with tracking and navigation manoeuvres. The actual
Earth swing-by took place on 13-Nov-07. The perigee altitude was
13890 km. The relative approach and departure velocity was 9.3 km/s.
The phase ended one month after the LGA strobing phase. In this phase
the spacecraft got very close to the sun (min distance 0.91AU). One 15
day payload checkout and one 5 day payload checkout were also
scheduled in this phase (PC6 and PC7).
Payload Checkout 6 (PC6) was an active checkout where a target
independent opportunity to perform interactive operations and to
request spacecraft pointing was given to all Rosetta payload teams.
The active payload checkout 6 ran for 15 consecutive days starting on
the 13th September 2007 until the 29th September 2006.
All Rosetta payload took part in this scenario. Operations ranged from
a repeat of established passive checkout operations to extensive
software patching and calibration campaigns. Four instruments required
active spacecraft pointing during the scenario with nine different
targets observed. Pointing types were 7 stares, 2 slew scans, 2 raster
scans giving a total of around 176 hours of dedicated spacecraft
pointing. These were mostly for calibration purposes.
Overall operations went smoothly. Although several open issues were
resolved in this checkout several issues remained open and new ones
have been generated.
Payload Checkout 7 (PC7) was a passive checkout run form 4th January
2008 to 9th January 2008. Main objectives have been met with no issue
apart from GD. This issue was due to higher operating temperatures
resulting from the short Sun-Spacecraft distance.
The Payload checkout reports are:
[RO-SGS-RP-0004]
_Rosetta_Report_Active_Payload_Checkout_6_2007Oct30.doc
[RO-SGS-RP-0005]
_Rosetta_Passive_Payload_Checkout_7_Report_2008Jun24.pdf.
Cruise phase 4 (split into 4-1 and 4-2)
--------------
In this phase the spacecraft made one revolution around the Sun.
A solar conjunction took place in January 2009 (see Solar Conjunctions
section above), together with another two conjunctions of the Earth-
spacecraft- Sun angle (Sun-Earth conjunction as seen from the
spacecraft). In this phase the spacecraft got very close to the sun
(min distance 0.91AU). This Cruise phase has been splitted in two
parts after the selection of the first Asteroid flyby which fell
in the middle of this phase. Cruise 4-1 was before the flyby phase,
and 4-2 was right after. Two passive check-outs were scheduled, one
during Cruise 4-1 and the second one during Cruise 4-2.
During CR4, Passive Checkout 9 and Active Checkout 8 were planned.
Payload Checkout 8 (PC8) was an active checkout where a target
independent opportunity to perform interactive operations and to
request spacecraft pointing was given to all Rosetta payload teams.
All Rosetta payload took part in this scenario.
The Active Payload Checkout 8 ran for 2 days (05-06 July 2008) plus 26
consecutive days starting on the 9th July 2008 until the 1st August
2008.
Three instruments required active spacecraft pointing during the
scenario with 9 different targets observed. Pointing types were 14
stares and 3 raster scans. These were mostly for calibration purposes.
Payload Checkout 9(PC9) was a passive checkout executed between 28th
January and 2nd February 2009. An RSI passive checkout was also
completed on 09th February. All but 2 of the Rosetta payload
instruments participated in the scenario, the exceptions being Rosina
and Virtis. Operations were limited to instrument health checks and
passive checkouts, as is the case for nominal Passive Checkout
scenarios. All of the operations planned and executed in the PC09
scenario were successful (as detailed in Section 3). Minor issues were
observed by 2 instruments (CN and RS) but none of these prevented the
successful completion of the corresponding operations.
The Payload checkout reports are:
[RO-SGS-RP-0019]
_Rosetta_Report_Active_Payload_Checkout_8_2011Jul25.pdf
[RO-SGS-RP-0030]
_Rosetta_Report_Passive_Payload_Checkout_9_2011Jul20.pdf
Steins flyby
-------------
Asteroid Steins was the first dedicated scientific target of the
Rosetta mission. Closest approach was on 5 September 2008 at 18:38:22
UTC. Rosetta flew at 800 km from asteroid Steins. For the first time a
European spacecraft flew next to an asteroid, performed an optical
navigation campaign, and autonomously tracked the asteroid by means of
its on board camera.
The 2867 Steins E-type asteroid had been discovered on 4 November 1969
by N. Chernykh. Its dimensions have been estimated by [KELLERETAL2010]
to 6.67 x 5.81 x 4.47 km3, corresponding to a spherical equivalent
radius of 2.65 km. Its sidereal rotation period has been estimated to
6.04681 +/- 0.00002h, its pole direction in ecliptic coordinates to
approximately Lambda = 250 deg and Beta = -89 deg with an error of
about 5 degrees [LAMYETAL2008]. Its albedo has been estimated to 0.3
in the visible and 0.4 in the infrared, both by [KELLERETAL2010] and
[LAMYETAL2008].
The two asteroids Rosetta flew by are secondary science targets of the
Rosetta mission, with comet 67P/Churyumov-Gerasimenko being the
primary science target. Therefore, scientific measurements of Asteroid
(2867) Steins had highest priority. Some calibrations were also
performed during the flyby phase.
The flyby geometry necessitated a flip in the spacecraft attitude
before closest approach. As a compromise between the incompatible
requirements to minimize the illumination of the -X and +-Y panels of
the spacecraft (flip as late as possible) and to minimize the impact
on the science observations (flip as early as possible), the
spacecraft flip was performed between 40 and 20 minutes before closest
approach. Rosetta's relative speed with respect to Steins was 8.6km/s.
The heliocentric and geocentric distances of Rosetta during the Steins
flyby were 2.14 AU and 2.41 AU, respectively. The one way light travel
time was 20 minutes.
The estimated accuracy of the determination of the position of Steins
in the plane perpendicular to the flight direction during the naviga-
-tion campaign was +/-2 kms for navigation with OSIRIS and +/-16 kms
for navigation with the NAVCAMs (from navigation slot on Sept. 4). For
the targeted passage through phase angle 0 at a distance of 1280 kms
from Steins, a positional offset of 2 kms would correspond to a
minimum phase angle of 0.1 degree.
The following table shows an overview of the Steins Flyby scenario:
------------------------------------------------------------------
| Start Date | End Date | Operation |
------------------------------------------------------------------
| 04/08/2008 | 04/09/2008 | Navigation campaign (astrometry) using|
| | | NAVCAM and OSIRIS NAC |
------------------------------------------------------------------
| 01/09/2008 | 10/09/2008 | Scientific operations targeting the |
| | | asteroid |
------------------------------------------------------------------
| 07/09/2008 | 04/10/2008 | Observation of gravitational |
| | | microlensing events in the galactic |
| | | bulge by OSIRIS |
-------------------------------------------------------------------
The following table shows the observation results per instrument:
----------------------------------------------------------------------
| Instrument| Title |Success| Comments |
----------------------------------------------------------------------
| ALICE 01 | Alice optics | Yes | at the beginning and |
| | decontamination | | end of all scenarios |
|--------------------------------------------------------------------|
| ALICE 02 | Standard stellar flux | Yes | During major |
| | calibration using the AL| | scenarios |
| | narrow center boresight | | |
|--------------------------------------------------------------------|
| ALICE 03 | Standard stellar flux | Yes | During major |
| | calibration using the AL| | scenarios |
| | +X wide bottom boresight| | |
|--------------------------------------------------------------------|
| ALICE 04 | Dark exposures | Yes | Regular calibration |
|--------------------------------------------------------------------|
| ALICE 05 | Search for evidence of | Yes | No exosphere or coma |
| | exosphere/coma around | | found |
| | Steins | | |
|--------------------------------------------------------------------|
| ALICE 06 | Point at Steins to | Yes | First Spectrum of an |
| | obtain an FUV spectrum | | asteroid below 200nm |
|--------------------------------------------------------------------|
| ALICE 07 | Point to the Steins RA | Yes | |
| | and Dec at the mid point| | |
| | of AL 06 observation | | |
|--------------------------------------------------------------------|
| ALICE 08 | Point to the Steins RA | Yes | |
| | and Dec at the mid point| | |
| | of AL 05 observation | | |
|--------------------------------------------------------------------|
| ALICE 09 | Standard stellar flux | Yes | During major |
| | calibration using the AL| | scenarios |
| | -X wide top boresight | | |
|--------------------------------------------------------------------|
| COSIMA 01 | Image and expose D8 | No | TMU error |
| | substrate | | |
|--------------------------------------------------------------------|
| COSIMA 02 | Image all D8 substrates | No | Cancelled after |
| | and store it | | failure of CS 01 |
|--------------------------------------------------------------------|
| GIADA 01 | non nominal operational | Yes | |
| | configuration, i.e. only| | |
| | impact sensor on and | | |
| | cover closed | | |
|--------------------------------------------------------------------|
| LANDER 01 | Run MUPUS TEM mode | Yes | |
| | during periods with | | |
| | pronounced temperature | | |
| | changes | | |
|--------------------------------------------------------------------|
| LANDER 02 | Operate ROMAP in slow | Yes | Interference from |
| | mode and fast mode | | MUPUS detected |
| | during CA +/-30min | | |
|--------------------------------------------------------------------|
| LANDER 03 | CASSE measurements | Yes | |
| | during WOL with SW FM-2 | | |
|--------------------------------------------------------------------|
| LANDER 04 | Thermal test of SESAME | Yes | |
| | soles | | |
|--------------------------------------------------------------------|
| LANDER 05 | Operation of CASSE and | Yes | |
| | DIM in a dusty environ-| | |
| | -ment | | |
|--------------------------------------------------------------------|
| MIRO 01 | Observation of Steins | Yes | |
| | during approach | | |
|--------------------------------------------------------------------|
| MIRO 02 | Run Asteroid Mode | Yes | Pointing inaccuracy |
| | sequence at closest | | during Asteroid Flyby|
| | approach to Steins | | mode affects scienti-|
| | | | -fic output |
|--------------------------------------------------------------------|
| MIRO 03 | Observation of Steins | Yes | |
| | during Recession | | |
|--------------------------------------------------------------------|
| ROSINA 01 | Outgassing | Yes | |
|--------------------------------------------------------------------|
| ROSINA 02 | Single mass measurement | Yes | Contamination issue |
| | sequence | | due to s/c flip. |
| | | | Sw instability caused|
| | | | temporary switch-off |
| | | | of detector |
|--------------------------------------------------------------------|
| ROSINA 03 | Pressure monitoring | Yes | Contamination issue |
| | | | due to s/c flip |
|--------------------------------------------------------------------|
| RPC 01 | Steins Fly by | Mostly| ICA did not produce |
| | | | scientifically useful|
| | | | data due to a comman-|
| | | | -ding error. |
| | | | Interference from |
| | | | MUPUS detected |
|--------------------------------------------------------------------|
| RSI 01 | Coherent measurement | TBD | TBD |
| | with Xup/Xdown or Xup/ | | |
| | Sdown received by a | | |
| | groundstation capable of| | |
| | receiving X- and S- band| | |
| | Doppler and Ranging | | |
| | Signals | | |
|--------------------------------------------------------------------|
| SREM 01 | SREM standard | YES | No Steins specific |
| | accumulation | | operations, general |
| | | | particle flux |
| | | | monitoring |
|--------------------------------------------------------------------|
| OSIRIS 01 | Vega Stare | Yes | Stellar calibrations |
| | | | repeated during major|
| | | | scenarios |
|--------------------------------------------------------------------|
| OSIRIS 02 | 16 Cyg Stare | Yes | Stellar calibrations |
| | | | repeated during major|
| | | | scenarios |
|--------------------------------------------------------------------|
| OSIRIS 03 | Steins Lightcurve at | Yes | TBD |
| | CA-2 weeks | | |
|--------------------------------------------------------------------|
| OSIRIS 04 | Steins Lightcurve at | Mostly| WAC data compromised |
| | CA-24 hours | | by overexposure |
|--------------------------------------------------------------------|
| OSIRIS 05 | Steins observation at CA| Mostly| NAC went into Safe |
| | | | mode due to shutter |
| | | | issues about 10 min |
| | | | before CA |
|--------------------------------------------------------------------|
| OSIRIS 06 | Fast imaging sequence | Yes | observation merged |
| | around the time of phase| | with OSIRIS 05 |
| | angle 0 | | |
|--------------------------------------------------------------------|
| OSIRIS 07 | Characterization of | Yes | TBD |
| | solar straylight for | | |
| | same orientation as the | | |
| | one the s/c had when | | |
| | the OSIRIS hill sphere | | |
| | dust search was | | |
| | performed | | |
|--------------------------------------------------------------------|
| VIRTIS 01 | VIRTIS-M lightcurve of | Yes | TBD |
| | Steins | | |
|--------------------------------------------------------------------|
| VIRTIS 02 | V-M and V-H operating; | Yes | Operations were |
| |s/c stare at target Nadir| |affected by inaccuracy|
| | looking; continuous | | of s/c pointing |
| | acquisition in pushbroom| | |
| | mode | | |
|--------------------------------------------------------------------|
| VIRTIS 03 | V-M and V-H continuous | Yes | TBD |
| |observation of Steins for| | |
| | 1 hour after VR02; V-M | | |
| | in image mode (10 lines | | |
| | scan) | | |
|--------------------------------------------------------------------|
The Rosetta first asteroid flyby was a success. The navigation
campaign produced highly accurate predictions of the Steins position,
and during the flyby most instruments worked without serious problems.
Asteroid flyby mode worked well, although with somewhat lower tracking
accuracy than expected.
Summary results per instrument during closest approach can be found in
the operation report:
[RO-SGS-RP-0020] Science Operations Report for the Steins FlyBy
Earth swing-by 3
----------------
Operations were essentially the same as for the Earth swing-by 2. The
actual Earth swing-by took place in Nov-09. The perigee altitude was
300 km. The relative approach and departure velocity was 9.9 km/s.
Phase started 3 months before the swing-by and ends 1 month later. Two
short payload checkouts of about 5 days each were scheduled during
this phase.
The phase contained the Active Payload Checkout 10 (PC10). The section
first describes PC 10 and then the Earth Flyby.
PC10
----
The Active PC10 ran for 18 consecutive days from 18th September 2009
to 4th October 2009. It represented a target independent opportunity
to perform interactive operations and to request spacecraft
pointing. All payloads took part in this scenario, as interactive
or non-interactive operations. There were approximately 425 hours of
non-interactive and 68 hours of interactive operations. Four
instruments required active s/c pointing with 15 targets observed
(111 hours of dedicated s/c pointing). These were mostly for
calibration purposes.
More details on the results can be found in the report:
[RO-SGS-RP-0022] Payload Report Active PC10
Earth flyby 3 (EAR3)
--------------
This was the last of the three gravity assists from the Earth, after
which Rosetta increased its orbital energy, enough to allow the
scheduled encounter with the asteroid 21-Lutetia and the rendezvous
with Churyumov-Gerasimenko. From an operational point of view, the
swing-by spacecraft operations were of highest priority, and both
science observations and payload operations were only allowed on a
non-interference basis with those. Keeping this in mind, Rosetta had
the opportunity to perform special scientific observations of the
Earth-Moon system, instrument calibrations using Earth and/or Moon
and public relations observations.
The criticality of the spacecraft operations left payload operations
in a second place, provided that Earth is not a scientific target
for Rosetta and that potential trajectory correction manoeuvres
would force the cancellation of all of them. This is reflected in
the fact that only six instruments took part in the operations:
ALICE, MIRO, OSIRIS, RPC, VIRTIS and SREM.
Operation scheduling was centred on Earth Closest Approach,
which took place on 13 Nov. 2009 at 07:45:40 UTC, and overall
operations went smoothly, despite some scattered events.
According to the available reports, the EAR3 can be considered as
fully successful.
EAR3 results are described in [RO-SGS-RP-0023].
Cruise phase 5
--------------
One Active checkout (12) was scheduled during this cruise phase.
It can be noted that Passive Checkout 11 were cancelled since there
was not enough time to include it between PC10 and PC12. PC 11 was
supposed to be passive meaning that it is mainly instrument
health check operations. PC 10 and 12 are active and more important to
preserve.
Payload Checkout 12 (PC12) was an active checkout that ran for 23
consecutive days starting on the 22nd April 2010 until the 14th May
2010. All Rosetta payload took part in this scenario. Operations
ranged from a repeat of established passive checkout operations to
extensive software patching and calibration campaigns.
Overall operations went smoothly. Numerous open issues were resolved
in this checkout, whilst several issues remain open and new ones have
been generated. There was a particularly noticeable and positive
increase in the success rate of payload operations, when compared to
previous Scenarios.
All results can be read in [RO-SGS-RP-0027] report.
Lutetia Flyby (17/05/2010 - 03/09/2010)
--------------
The second of the flybys took place on 10 July 2010 to the asteroid
21 Lutetia, discovered on 15 November 1852 by H. Goldschmidt. Its
classification into a specific asteroid type had turned out to be
ambiguous and included the possibilities of a C-type or an M-type
asteroid. This contradiction made it an interesting object for close
inspection.
Closest Approach (CA) occurred at 15:45 UT at a distance of 3168.2km.
The relative fly-by velocity was of 15 km/s. The fly-by strategy
allowed continuous observations of Lutetia before, during and for 30
minutes after CA.
Images obtained by OSIRIS revealed that Lutetia has a complex geology
and one of the highest asteroid densities measured so far,
3.4+/-0.3g/cm3. Its geologically complex surface, ancient surface age
and high density suggest that Lutetia is most likely a primordial
planetesimal.
This is the second of the two asteroids selected at the Science
Working Team meeting on 11th March 2004 among all the available
candidate asteroids, depending on the scientific interests and the
propellant required for the correction manoeuvre.
The following operations took place around the Lutetia fly-by:
21 May 2010 - 9 July 2010: Navigation campaign (astrometry) using the
OSIRIS NAC and NAVCAM.
5 July 2010- 14 July 2010: scientific operations targeting the
asteroid.
The Lutetia fly-by was a success. The navigation campaign produced
highly accurate predictions of the position of Lutetia and during
the fly-by most instruments worked without serious problems (except
Rosina, RPC IES and RPC ICA). Asteroid fly-by mode worked excellently.
The objectives summarised below have been addressed by the instrument
measurements:
- Physical and thermal properties, mineralogy and geomorphology of
Lutetia from spatially resolved multi-wavelengths remote-sensing
observations between the extreme UV and the mm-range.
- Determination of the mass of the asteroid from Doppler
measurements of the spacecraft trajectory.
- Global shape parameters from light curves taken days before CA.
- Search for satellite/dust particles.
- Search for an asteroid magnetic field.
- Particle and field measurements.
Results of the Lutetia Fly By can be found in [RO-SGS-RP-0028].
Rendez-Vous Manoeuver 1 (04/09/2010 - 13/07/2011)
----------------------
The deep space manoeuvre was carried out when the spacecraft reached
a distance from the Sun around 4.5 AU on 23-Jan-11. One passive check
-out (13) was scheduled during this phase. One solar conjunction of
50 days and one solar opposition of 37 days happened during this
phase.(see Solar Conjunctions section above).
--PC 13 (1st-9th Dec 2010 + 14th Dec)
This was the final Cruise Phase Checkout. A number of additional
payload operations were also executed, to close out pending and
essential requirements, and/or to configure instruments for the
upcoming Deep Space Hibernation Phase. Only OSIRIS did not participate
in PC 13. PC13 ran for 9 consecutive days between 1st and 9th December
2010. A RSI passive checkout was also completed on 14th December.
All of the operations planned and executed were successful. Minor
issues were observed by 4 instruments (Consert, Philae, Rosina, RPC).
Alice performed successfully some instrument checkout.
Cosima did periodical maintenance and check its status.
Giada checked successfully its status.
Midas performed a normal passive check-out and an additional modified
one for Deep Space Hibernation Preparation.
Miro performed a normal and successful passive check-out.
Osiris did not participate in the PC13 timeframe. However, on 23-26th
March 2011 - post RVM1 - specific OSIRIS operations were performed in
order to prepare and configure the instrument for the Rosetta Deep
Space Hibernation.
The Lander performed some operations and Consert performed an unit
functional test; both were partially successful.
Rosina did not participate in the nominal PC13 scenario, but conducted
several specific operations immediately following completion of the
nominal PC13 timeline. A spacecraft slew was executed with RTOF
monitoring, to further investigate data observed during Lutetia
fly-by.
RPC PIU, IES, LAP, ICA performed checkout with some errors/anomalies
reported, which were considered as no problem for the instrument.
Virtis performed the checkout successfully.
RSI measurements during PC13 showed some disturbances. The cause is
unknown at the time being.
SREM performed a successful checkout.
More detailed results can be found in [RO-SGS-RP-0029].
Cruise phase 6 (8 Jun 2011 - 20 Jan 2014)
--------------
The whole period was spent in Deep-Space Hibernation Mode (DSHM).
Maximum distances to Sun and Earth are encountered during this
period, i.e. 5.3 AU (aphelion) and 6.3 AU, respectively. During this
phase, 3 superior solar conjunctions and 2 solar oppositions occurred
(see table above). This phase ended with the Spacecraft wake-up on
the 20th of January 2014.
Rendez-Vous Manoeuver 2 (21 Jan 2014 - 9 Sep 2014)
----------------------
The RVM2 started after Spacecraft wake-up and until September 2014,
when the Global Mapping phase started. It contained the Near Comet
Drift (NCD), the Far Approach Trajectory (FAT) and the Close Approach
Trajectory (CAT). It ended with the transition to Global Mapping.
During this phase, Rosetta did a series of ten OCMs, starting on the
7 May to reduce its speed with respect to comet 67P/C-G by about
775 m/s. The first, producing just 20 m/s delta-v ( change in
velocity ), was done as a small test burn, as it was the first use of
the spacecraft s propulsion system after wake-up.
--Near comet drift (NCD) phase (21 May 2014 - 2 July 2014)
The following three OCMs form the Near Comet Drift (NCD) phase.
They took place every two weeks starting 21 May. They delivered
289.6, 269.5 and 88.7 m/s in delta-v, respectively.
-- Far Approach Trajectory (FAT) (2 July - 3 August 2014)
The FAT contained the next four burns. The four FAT burns was
carried out weekly during July, and all proceeded nominally. The
approach manoeuvre sequence reduced the relative velocity in stages
down to 3 m/s.
During this phase, the first images of the comet were obtained with
the optical measurement system (NAVCAM, OSIRIS). After detection,
knowledge of the comet ephemeris was drastically improved by
processing the on-board observations. Image processing on the ground
derived a coarse estimation of comet size, shape and rotation.
The first landmarks were identified.
The FAT ends at the Approach Transition Point (ATP), which is
located in the Sun direction at about 1000 comet nucleus radii from
the nucleus.
Find below a list of burns with delta-v reduction and duration
Date Delta-V m/s Dur.(mins)
7 May 20 41
21 May 290 441
4 Jun 270 406
18 Jun 91 140
2 Jul 59 94
9 Jul 26 46
16 Jul 11 26
23 Jul 5 17
3 Aug 3 13
6 Aug 1 7
-- Close Approach Trajectory (CAT)
Close approach trajectory operations started at ATP. The spacecraft
distance to the comet was decreased to 20 nucleus radii and the
relative velocity fell below 1 m/s. The final point of this phase
was the Orbit Insertion Point (OIP), the point where the spacecraft
started orbiting the comet.
During the CAT, 5 landing sites were selected by the Landing team.
Details of the final manoeuvres to prepare insertion:
6 August: Rosetta was commanded to conduct a 1-m/s thruster burn
(which ran 7 min) to change its direction and enter onto the first
arc (of three arcs) of two triangular (really, tetrahedral) orbits
about the comet.
It is important to note Rosetta has not been captured by 67P/C-G
gravity, and the continuing series of thruster burns were
necessary to keep the spacecraft at the comet.
Rosetta executed two of these triangular orbits, one large, at
about 100km closest pass-by distance (Big CAT) and the second at
about 50km ( Little CAT ).
10 August: CAT Change 1 burn - a 6min:25sec, 0.88-m/s burn that
pushed Rosetta onto the next arc (100km pass-by height).
13 August: CAT Change 2 burn - a 6min:22sec, 0.87-m/s burn that
pushed Rosetta onto the next arc (100km pass-by height).
17 August: CAT Change 3 burn - a 6min:19sec, 0.85-m/s burn that
pushed Rosetta onto a transfer arc, down to about 80 km height
achieved on 20 Aug (CAT 4).
Finally, with the next two burns on 24 and 27 August, the distance
was lowered to 50km.
- Transition to Global Mapping (TGM)
On 31 August, Rosetta began the third and last arc of Little CAT
and Rosetta entered the TGM, a set of two manoeuvres.
The phase ended at 10 nucleus radii with ta relative velocity of
0.3 m/s.
Global Mapping and Close Observations (10 sep 2014 - 28 Oct 2014)
The Global Mapping phase ran 10 September to 15 October. During this
phase, Rosetta went down to 29 km distance, a point when the
spacecraft became actively captured by the comet gravity, and its
orbit became circular.
At the beginning of this phase, the Lander team down selected 2
landing sites: the nominal and the back up.
A series of manoeuvres reduced Rosetta distance from 18.6 km orbit
(taking 7 days) to an intermediate orbit approximately 18.6 x 9.8 km
(with a period of 5 days). From there the orbit was circularised at
about 9.8 km radius, with a period of approximately 66 hours on 15
October, and the mission entered the Close Observation Phase (COP).
This phase provided even higher resolution images of the landing
site in order to best prepare for Philae's challenging touch-down.
The new orbit also allowed a number of Rosetta's science instruments
to collect dust and measure the composition of gases closer to the
nucleus.
On the 28 October, Rosetta conducted a thruster burn (82 sec from
12:59 UTC) that delivered a delta-v of 0.081 meters/sec. This pushed
the spacecraft to leave the 10-km-altitude circular orbit (following
the terminator line) and the COP. Rosetta started its transition to
the pre-lander-delivery orbit.
On 31 October, the mission control team performed another manoeuvre
to enter onto the pre-delivery orbit proper.
Lander delivery
---------------
On 31 October, Rosetta entered a pre-delivery elliptical orbit at
approximately 30 km distance from the comet centre. This orbit was
maintained until delivery on 12 November.
The orbiter performed its pre-separation manoeuvre at 6:04 on 12
November, which placed it on the trajectory required for separation.
The separation occurred at 08:35 UTC (the confirmation signal arrived
on Earth at 09:03 UTC). At 10:34 UTC the Lander activated its
transmitters and started forwarding its telemetry to the orbiter. At
11:08 UTC, this telemetry was received on ground.
Touchdown was confirmed for Philae at 16:03 UTC.
While Lander telemetry kept flowing towards the Orbiter, the RF link
between the two crafts was regularly interrupted, which was not
consistent with a stable landing. Other Lander telemetry gave
indication that the Lander had bounced after initial touch-down.
The link between Orbiter and Lander was broken at 17:59 UTC one hour
earlier than expected for the targeted landing site.
On 13 November Lander telemetry was received on ground at 6:01 UTC,
very close to the expected time.
During the descent, ROLIS acquired an image at 14:38:41 UT, from a
distance of approximately 3 km from the surface. The landing site was
imaged with a resolution of about 3m per pixel.
After separation, Orbiter operations focus on maximising visibility
with the Lander and acquiring data to reconstruct the Lander descent
trajectory and support Orbiter Navigation.
NAVCAM and OSIRIS, once in Lander pointing, acquired every hour until
touch-down + 2 hours. After that, NAVCAM observed every 2 hours for
navigation.
The following Orbiter instruments have been operated: ALICE, CONSERT,
MIRO, OSIRIS, ROSINA, RPC.
The post-delivery manoeuvre that has been executed on 12 November 2014
started at 09:14:58.1 UTC and a nominal end time at 09:19:53.7 UTC.
Rosetta was then on a 50 km orbit.
On 13 November at 19:23 UTC Philae started transferring data to
Rosetta. Link was lost at 23:08 UTC on 13 November, 40 minutes before
predicted time.
During this slot was commanded:
- ranging measurements by CONSERT (Lander Search)
- CIVA images
- MUPUS boom deployment and hammering
- APXS deployment and measurement
On 14 November at 9:01, Philae data were received on-board Rosetta and
immediately transmitted to ground, 48 minutes after expected time. The
visibility period finished at 11:47 UTC on 14 November, 50 minutes
earlier than predicted.
During this period was commanded:
- APXS released but measured copper thus revealing that the door had
not opened.
- MUPUS deployment was successful, hammering took place, SESAME
detected it
- Drill activation for sample return to COSAC
- PTOLEMY/COSAC spectra acquisitions
- CIVA image but dark.................................................
- Consert ranging
The fourth and last Philae visibility period started on 14 November at
22:15 UTC ground time. The LAnder bus voltage appeared to decrease
rapidly. On November 15 at 00:07, the link between Orbiter and Lander
broke.
Among the Lander operations carried out during the fourth visibility
period was a rotation of the Lander to increase the illumination of
its solar arrays.
After the planned Touch Down, the Lander did not anchor and bounced.
We estimated that the first TD was:
Time UTC: 15:34:06
Comet-fixed coordinates: [2.129171, -0.961358, 0.498268] km
The NAVCAM image, the NAC image and the first TD as the starting point
gave the following impact point at:
Time UTC: 16:26:23
Comet-fixed coordinates: [2.450, -0.511, -0.242] km
This point has an uncertainty of 7 minutes. The position is also
uncertain.
By using three WAC images, the second TD can be deduced:
Time UTC: 17:31:10
Comet-fixed coordinates: [2.275, 0.249, -0.444] km
Consert Ranging estimated a final landing site at
Comet-fixed coordinates: [2.446, -0.055, -0.360] km
After Touch Down, began the First Science Sequence (FSS) where all
Lander instruments operated on the primary battery. The operations
did not go as planned due to the several TDs but occurred as listed
above. The Long Term Science Phase should have started after the
primary battery died, but the final TD let the Lander in a location
where the illumination condition could not allow battery charging.
Contact was lost on 15 November 2014 at 00:07, ending the FSS, and the
Lander went asleep.
Escort phase
------------
Planning period during the comet phase were approximately monthly and
allowed changes in trajectory types every two weeks. The table below
summarises the trajectory followed by Rosetta after the Landing:
21 Nov - 3 Dec 2014 | Bound Orbits at 30 km
3 Dec - 6 Dec 2014 | Transition
6 Dec - 19 Dec 2014 | Bound Orbit at 20 km
19 Dec - 24 Dec 2014 | Transition
24 Dec - 4 Feb 2015 | Bound Orbit at 28 km
4 Feb - 21 Feb 2015 | Close FlyBy CA on 14 Feb at 8km
| Leg up to 143km
21 Feb - 10 Mar 2015 | Arcs around 80 km
Apr 2015 | Fly bys: CA of 90 km and maximum distance
| of 180km
May 2015 | Fly bys: first from 125km to 180 km then from
| 200km to 325km
June 2015 | Fly bys: from 200 to 240km then CA to 160km
| Sub s/c point located North for Lander com.
July 2015 | Fly bys: CA at 150 km
Aug 2015 | Fly bys: CA increased to 180 km (star tracker
| issues.
Sept 2015 | Fly bys: between 400 and 460km first then
| reduced to 300-330 km
Oct 2015 | Far excursion at 1500 km
Nov 2015 | Fly bys from 420 to 140km
Dec 2015 | Fly bys (75-150km)
Jan 2016 | Fly bys (45-95km)
Feb 2016 | Fly bys (32-52km)
Mar 2016 | Terminator orbit (17 to 12km) - night side
| excursion - far excursion at 1000km -
| hyperbolic arcs at 200km
Apr 2016 | Far Flyby arcs at 200km in terminator - Flyby
| arcs at 80 km at 80 deg - Close Flyby at 30km
| Outbound arc (140 to 70km) at terminator -
| insertion into bound orbits at 19km dist.
May 2016 | Bound orbits in terminator plane: first
| elliptical 19kmx10km - circular 10km -
| circular 7km - mapping orbit at 17km.
Jun 2016 | Mapping orbit at 17km - at 30 km - 2 day-side
| half orbit at 45 deg phase angle - elliptical
| 28x14km at terminator
Jul 2016 | 2.5 elliptical orbit 26x9km at terminator -
| circular orbit at 10 km at terminator
26 Jul - 9 Aug 2016 | 4 elliptical orbits 14x8km with 70-110 deg
| phase angles
9 Aug - 2 Sep 2016 | elliptical orbits (70-110 deg phase angles).
| Pericentre gradually reduced and apocentre
| increased while constant orbital period of 3
| days 13.7km, 7.5km, 13.7km, 6.7km, 14.4km,
| 6.0km, 15.1km, 5.5km, 15.5km, 5.0km, 15.9km,
| 4.6km, 16.2km, 4.4km, 16.4km
2 Sep - 26 Sep 2016 | elliptical orbits (70-110 deg phase angles).
| Pericentre gradually reduced and apocentre
| increased while constant orbital period of 3
| days 4.0km, 17.1km, 3.9km, 17.1km, 4.1km,
| 16.1km, 4.1km, 16.8km, 4.1km, 16.0km, 4.1km,
| 17.0km, 4.1km, 16.7km, 4.1km, 17.2km
26 Sep - 30 Sep 2016 | exit from elliptical orbits - hyperbolic arcs
| with dist from 17 to 23km - final descent to
| the comet nucleus.
Orbiter Experiments
=====================================================================
ALICE
-----
ALICE, an Ultraviolet Imaging Spectrometer, characterise the
composition of the nucleus and coma, and the nucleus/coma coupling of
comet 67 P/Churyumov-Gerasimenko. This is accomplished through the
observation of spectral features in the extreme and far ultraviolet
(EUV/FUV) spectral regions from 70 to 205 nm.
ALICE make measurements of noble gas abundances in the coma, the
atomic budget in the coma, and major ion abundances in the tail and
in the region where solar wind particles interact with the ionosphere
of the comet. ALICE determine the production rates, variability,
and structure of H2O and CO, and CO2 gas surrounding the nucleus and
the far-UV properties of solid grains in the coma.
ALICE studied Mars and the Rosetta asteroid flyby targets while en
route to Churyumov- Gerasimenko. ALICE also map the cometary nucleus
in the FUV
Instrument References: [STERNETAL2007]
CONSERT
-------
CONSERT (Comet Nucleus Sounding Experiment by Radio wave
Transmission) is an experiment that perform tomography of the
comet nucleus revealing its internal structure. CONSERT operates as a
time domain transponder between the Lander on the comet surface and
the Orbiter. A radio signal passes from the orbiting component of the
instrument to the component on the comet surface and is then
immediately transmitted back to its source, the idea being to
establish a radio link that passes through the comet nucleus. The
varying propagation delay as the radio waves pass through different
parts of the cometary nucleus is used to determine the dielectric
properties of the nuclear material. Many properties of the comet
nucleus is examined as its overall structural homogeneity, the average
size of the sub-structures (Cometesimals) and the number and
thickness of the various layers beneath the surface.
Instrument References: [KOFMANETAL2007]
COSIMA
------
The Cometary Secondary Ion Mass Analyser is a secondary ion mass
spectrometer equipped with a dust collector, a primary ion gun, and
an optical microscope for target characterization. Dust from the near
comet environment is collected on a target. The target is then moved
under a microscope where the positions of any dust particles are
determined. The cometary dust particles are then bombarded with pulses
of indium ions from the primary ion gun. The resulting secondary ions
are extracted into the time-of-flight mass spectrometer.
Instrument References: [KISSELETAL2007]
GIADA
-----
The Grain Impact Analyser and Dust Accumulator measures the
scalar velocity, size and momentum of dust particles in the coma of
the comet using an optical grain detection system and a mechanical
grain impact sensor. Five microbalances measure the amount of
dust collected as the spacecraft orbits the comet.
Instrument References: [COLANGELIETAL2007]
MIDAS
-----
The Micro-Imaging Dust Analysis System is intended for the
microtextural and statistical analysis of cometary dust particles.
The instrument is based on the technique of atomic force microscopy.
This technique, under the conditions prevailing at the Rosetta
Orbiter permits textural and other analysis of dust particles to be
performed down to a spatial resolution of 4nm.
Instrument References: [RIEDLERETAL2007]
MIRO
----
MIRO (Microwave Instrument for the Rosetta Orbiter) is composed of a
millimetre wave mixer receiver and a submillimetre heterodyne
receiver. The submillimetre wave receiver provides both broad band
continuum and high resolution spectroscopic data, whereas the
millimetre wave receiver provides continuum data only.
MIRO measures the near surface temperature of the comet, allowing
estimation of the thermal and electrical properties of the surface.
In addition, the spectrometer portion of MIRO allows measurements
of water, carbon monoxide, ammonia, and methanol in the comet coma.
Instrument References: [GULKISETAL2007]
OSIRIS
------
OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System)
is a dual camera imaging system operating in the visible, near
infrared and near ultraviolet wavelength ranges. OSIRIS consists of
two independent camera systems sharing common electronics. The narrow
angle camera is designed to produce high spatial resolution images of
the nucleus of the target comet. The wide angle camera has a wide
field of view and high straylight rejection to image the dust and gas
directly above the surface of the nucleus of the target comet. Each
camera is equipped with filter wheels to allow selection of imaging
wavelengths for various purposes. The spectroscopic and wider band
infrared imaging capabilities originally proposed and incorporated in
the instrument name were descoped during development.
Instrument References: [KELLERETAL2006]
ROSINA
------
ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis)
consists of two mass spectrometers, since no one technique is able to
achieve the resolution and accuracy required to fulfil the ROSETTA
mission goals over the range of molecular masses under analysis. In
addition, two pressure gauges provide density and velocity data for
the cometary gas.
The two mass analysers are:
* A double focusing magnetic mass spectrometer with a mass range of 1
- 100 amu and a mass resolution of 3000 at 1 % peak height, optimised
for very high mass resolution and large dynamic range
* A reflectron type time-of-flight mass spectrometer with a mass
range of 1 -300 amu and a mass resolution better than 500 at 1 % peak
height, optimised for high sensitivity over a very broad mass range
Instrument References: [BALSIGERETAL2007]
RPC
---
RPC (Rosetta Plasma Consortium) is a set of five sensors sharing a
common electrical and data interface with the Rosetta orbiter. The
RPC sensors are designed to make complementary measurements of the
plasma environment around the comet 67P/Churyumov-Gerasimenko.
The RPC sensors are:
* ICA: an Ion Composition Analyser, which measures the three-
dimensional velocity distribution and mass distribution of positive
ions;
* IES: an Ion and Electron Sensor, which simultaneously measures
the flux of electrons and ions in the plasma surrounding the comet;
* LAP: a Langmuir Probe, which measures the density, temperature
and flow velocity of the cometary plasma;
* MAG: a Fluxgate Magnetometer, which measures the magnetic field
in the region where the solar wind plasma interacts with the comet;
Instrument References: [GLASSMEIERETAL2007B]
* MIP: a Mutual Impedance Probe, which derives the electron plasma
density, and can sometimes constrain other plasma parameters of the inner
coma of the comet.
Instrument References: [CARRETAL2007]
RSI
---
RSI (Radio Science Investigation) makes use of the communication
system that the Rosetta spacecraft uses to communicate with the
ground stations on Earth. Either one-way or two-way radio links can
be used for the investigations. In the one-way case, a signal
generated by an ultra-stable oscillator on the spacecraft is received
on earth for analysis. In the two way case, a signal transmitted from
the ground station is transmitted back to Earth by the spacecraft. In
either case, the downlink may be performed in either X-band or both X
-band and S-band.
RSI investigates the nondispersive frequency shifts (classical
Doppler) and dispersive frequency shifts (due to the ionised
propagation medium), the signal power and the polarization of the
radio carrier waves. Variations in these parameters yields
information on the motion of the spacecraft, the perturbing forces
acting on the spacecraft and the propagation medium.
Instrument References: [PAETZOLDETAL2007]
VIRTIS
------
VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) is an
imaging spectrometer that combines three data channels in one
instrument. Two of the data channels are committed to spectral
mapping and are housed in the Mapper optical subsystem. The third
channel is devoted solely to spectroscopy and is housed in the High
resolution optical subsystem.
The mapping channel optical system is a Shafer telescope consisting
of five aluminium mirrors mounted on an aluminium optical bench. The
mapping channel uses a silicon charge coupled device (CCD) to detect
wavelengths from 0.25 micron to 1 micron and a mercury cadmium
telluride (HgCdTe) infrared focal plane array (IRFPA) to detect from
0.95 micron to 5 microns.
The high resolution channel is an echelle spectrometer. The incident
light is collected by an off-axis parabolic mirror and then
collimated by another off-axis parabola before entering a cross-
dispersion prism. After exiting the prism, the light is diffracted by
a flat reflection grating, which disperses the light in a direction
perpendicular to the prism dispersion. The high-resolution channel
employs a HgCdTe IRFPA to perform detection from 2 to 5 microns.
Instrument References: [CORADINIETAL2007]
SREM
----
The Standard Radiation Environment Monitor (SREM) is a monitor-class
instrument intended for space radiation environment characterisation
and radiation housekeeping purposes. SREM provides continuous
directional, temporal, and spectral data of high-energy electron,
proton, and cosmic ray fluxes encountered along the orbit of the
spacecraft, as well as measurements of the total accumulated
radiation dose absorbed by SREM itself.
This instrument is a facility monitor flown on several ESA
spacecrafts. It is not considered as a PI (Principal Investigator)
instrument.
Instrument References: [MOHAMMADZADEETAL2003]
LANDER (PHILAE)
=====================================================================
The 100 kg Rosetta Lander, named Philae, is the first spacecraft
ever to make a soft landing on the surface of a comet nucleus. The
Lander is provided by a European consortium under the leadership of
the German Aerospace Research Institute (DLR) and the French Space
Research Center (CNES). Other members of the consortium are ESA and
institutes from Austria, Finland, France, Hungary, Ireland, Italy and
the UK. A description of the Lander can be found in [RO-EST-RS-3020].
The box-shaped Lander was carried in piggyback fashion on the side of
the Orbiter until it arrived at Comet 67P/Churyumov-Gerasimenko. Once
the Orbiter was aligned correctly, the ground station commanded the
Lander to self-eject from the main spacecraft and unfold its three
legs, ready for a gentle touch down at the end of the ballistic
descent. The Landing is described above.
Immediately after touchdown, a harpoon was supposed to fire to anchor
the Lander to the ground and prevent it escaping from the comet's
extremely weak gravity. The system did not work and the Lander bounced
several times.
Science Objectives
------------------
It is the general aim of the scientific experiments carried and
operated by the Rosetta Lander to obtain a first in situ composition
analysis of primitive material from the early solar system, to study
the composition and structure of a cometary nucleus, reflecting
growth processes in the early solar system, to provide ground truth
data for the Rosetta Orbiter experiments and to investigate dynamic
processes leading to changes in cometary activity.
The primary objective of the Rosetta Lander mission is the in situ
investigation of the elemental, isotopic, molecular and mineralogic
composition and the morphology of early solar system material as it
is preserved in the cometary nucleus. Measurement of the absorption
and phase shift of electromagnetic waves penetrating the comet
nucleus will help to determine its internal structure. Seismometry
and magnetometry will also be used to investigate the interior of the
comet.
The scientific objectives of the Rosetta Lander can be listed
according to their priority as follows:
1. Determination of the composition of cometary surface and
subsurface matter: bulk elemental abundances, isotopic ratios,
minerals, ices, carbonaceous compounds, organics, volatiles - also
in dependence on time and insolation.
2. Investigation of the structure and physical properties of the
cometary surface: topography, texture, roughness, regolith scales,
mechanical, electrical, optical, and thermal properties,
temperatures. Characterization of the near surface plasma
environment.
3. Investigation of the global internal structure.
4. Investigation of the comet/plasma interaction.
The in situ measurements performed by the Rosetta Lander instruments
will also provide local ground truth to calibrate Orbiter
instruments.
Lander Experiments
------------------
Here a description of all the instruments of the Lander:
APXS: Alpha-p-X-ray spectrometer
- - - - - - - - - - - - - - - -
The goal of the Rosetta APXS experiment is the determination of the
chemical composition of the landing site and its potential alteration
during the comet's approach to the Sun. The data obtained is
used to characterize the surface of the comet, to determine the
chemical composition of the dust component, and to compare the dust
with known meteorite types.
Instrument References: [KLINGELHOFERETAL2007]
CIVA: Panoramic and microscopic imaging system
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The Cometary Infrared and Visible Analiser (CIVA) is an integrated
set of imaging instruments, designed to characterize the landing and
sampling site, the 360 deg panorama as seen from the Rosetta Lander,
all samples collected and delivered by the Drill Sample and
Distribution System, and the stratigraphy within the boreholes. It is
constituted by a panoramic stereo camera (CIVA-P), and a microscope
coupled to an IR spectrometer (CIVA-M). CIVA is sharing a common
Imaging Main Electronics (CIVA/ROLIS/IME) with ROLIS. CIVA-P will
characterize the landing site, from the landing legs to the local
horizon. The camera is composed of 6 identical micro-cameras, mounted
of the Lander sides, with their optical axes separated by 60 deg. In
addition, stereoscopic capability is provided by one additional micro-
camera, identical to and co-aligned with one of the panoramic micro-
camera, with its optical axis 10 cm apart.
CIVA-M combines in separated boxes, two ultra-compact and
miniaturized channels, one visible microscope CIVA-M/V and one IR
spectrometer CIVA-M/I, to characterize, by non-destructive analyses,
the texture, albedo, mineralogical and molecular composition of each
of the samples collected and distributed by the Drill Sample and
Distribution System.
Instrument References: [BIBRINGETAL2007A]
CONSERT: Radio sounding, nucleus tomography
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The Comet Nucleus Sounding Experiment by Radio wave Transmission
(CONSERT) is a complex experiment that performs tomography of the
comet nucleus revealing its internal structure. CONSERT operates as a
time domain transponder between the Lander, on the comet surface and
the Orbiter orbiting the comet. A radio signal passes from the
orbiting component of the instrument to the component on the comet
surface and is then immediately transmitted back to its source, the
idea being to establish a radio link that passes through the comet
nucleus. The varying propagation delay as the radio waves pass through
different parts of the cometary nucleus is used to determine the
dielectric properties of the nuclear material. Many properties of the
comet nucleus is examined as its overall structural homogeneity, the
average size of the sub-structures (Cometesimals) and the number and
thickness of the various layers beneath the surface.
Instrument References: [KOFMANETAL2007]
COSAC: Evolved gas analyser - elemental and molecular composition
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The COmetary SAmpling and Composition experiment COSAC is one of the
two 'evolved gas analysers' (EGAs) on board the Rosetta-Lander.
Whereas the other EGA, Ptolemy, aims mainly at accurately measuring
isotopic ratios of light elements, the COSAC is specialised on
detection and identification of complex organic molecules. The
instrument can be described as an effort to analyse in situ, mainly
with respect to the composition of the volatile fraction, cometary
matter nearly as well and accurately as could be done in a laboratory
on Earth. Due to the Rosetta Lander rotatability, the instrument can
conduct analyses and investigations at different spots of the landing
site and, aided by the drill, take samples for analysis from a depth
up to at least 0.2 m.
Instrument References: [GOESMANNETAL2007]
PTOLEMY: Evolved gas analyser - isotopic composition
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The size of a small shoe box and weighing less than 5 kg, Ptolemy
uses gas chromatography / mass spectrometry (GCMS) techniques to
investigate the comet surface & subsurface. The instrument concept is
termed 'MODULUS' which is taken to mean Methods Of Determining and
Understanding Light elements from Unequivocal Stable isotope
compositions. The scientific goal of the PTOLEMY is to understand the
geochemistry of light elements, such as hydrogen, carbon, nitrogen
and oxygen, by determining their nature, distribution and stable
isotopic compositions.
Instrument References: [WRIGHTETAL2007]
MUPUS: Measurements of surface and subsurface properties
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The Multi-Purpose Sensor Experiment actually consists of four parts:
1. A penetrator, approximately 40 cm long, is hammered into the
ground about 1m apart from the Lander for measuring during the
penetration process the mechanical strength of the material by means
of a depth sensor and a densitometer. The penetrator is equipped with
a series of temperature sensors and heaters for determining the
temperature as a function of depth and insolation.
2. An accelerometer and a temperature sensor accommodated in the
harpoon(s)
3. A four-channel infrared radiometer measures surface temperatures
in the vicinity of the Lander. Density of the nearsurface (down to
20cm) material is determined by measuring the absorption of
gamma-rays emitted from a radioactive isotope mounted at the tip of
the penetrator.
Instrument References: [SPOHNETAL2007]
ROLIS: Descent & Down-Looking Imaging
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The ROLIS Camera (Rosetta Lander Imaging System) delivered first
close-ups of the environment of the landing place of comet
67P/Churyumov-Gerasimenko during the descent.
After landing ROLIS made high-resolved investigations to study
the structure (morphology) and mineralogy of the surface.
Instrument References: [MOTTOLAETAL2007]
ROMAP: Magnetometer and plasma monitor
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The Rosetta Lander Magnetometer and Plasma Monitor ROMAP is a multi-
sensor experiment. The magnetic field is measured with a fluxgate
magnetometer. An electrostatic analyzer with integrated Faraday cup
measures ions and electrons. The local pressure is measured with
Pirani and Penning sensors. The sensors are situated on a short boom.
The deployment on the surface of a cometary nucleus demanded the
development of a special digital magnetometer of little weight and
small power requirements. For the first time a magnetic sensor is
operated from within a plasma sensor. A prototype of the
magnetometer, named SPRUTMAG, was flown on space station MIR.
Instrument References: [AUSTERETAL2007]
SD2: Sampling, Drilling and Distribution Subsystem
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The Rosetta-Lander is equipped with a Sample Drill & Distribution
(SD2) subsystem which is in charge to collect cometary surface
samples at given depth and distribute them to the following
instruments: CIVA-M (microscope (MS) & Infrared Spectrometer (IS)),
the ovens, serving COSAC and PTOLEMY.
Comet sample from pre-determined and/or known (measured) depth are
collected and transported by SD2 to well defined locations:
* MS & IS viewing place
* ovens for high temperature (800 deg C) heating
* ovens for medium temperature (130 deg C) heating.
* ovens with a window, where samples can be investigated by CIVA-M
The sampling, drilling and distribution (SD2) subsystem provides
microscopes and advanced gas analysers with samples collected at
different depths below the surface of the comet. Specifically SD2 can
bore up to 250 mm into the surface of the comet and collect samples
of material at predetermined and/or known depths. It then transports
each sample to a carousel which feeds samples to different instrument
stations: a spectrometer, a volume check plug, ovens for high and
medium temperatures and a cleaning station. SD2 is accommodated
on the flat ground-plate of the Rosetta, where it is exposed to
the cometary environment.
Instrument References: [ERCOLIFINZIETAL2007]
SESAME: Surface electrical, acoustic and dust impact monitoring
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The SESAME (Surface Electrical, Seismic and Acoustic Monitoring
Experiments) electronics board and the integration of the components
are managed by the German Aerospace Center (DLR), Institute of Space
Simulation, Cologne.
The results of SESAME help in understanding how comets, have
formed and thus, how the solar system, including the Earth, was born.
Instrument References: [SEIDENSTICKERETA2007]
GROUND SEGMENT
=====================================================================
This section summarizes the roles and responsibilities for the
Rosetta Ground Segment.
The primary responsibility for developing the payload operations
strategy for the Rosetta Scientific Mission is the Rosetta Science
Working Team. The Rosetta Science Working Team (SWT) monitors and
advises on all aspects of Rosetta which affect its scientific
performance.
Rosetta Ground Segment
-----------------------
The Rosetta ground segment consists of two major elements: the
Rosetta Mission Operations Centre (RMOC) and the Rosetta Science
Ground Segment (RSGS).
Rosetta Science Ground Segment
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The Rosetta Science Ground Segment (RSGS) is located at the
European Space Astronomy Centre (ESAC) in Spain. The main task is to
support the Rosetta Project Scientist in the planning of the science
operations schedule and in the generation of coordinated operational
sequences, the payload command sequences for all Rosetta instruments
and their onward transmission to the Rosetta Mission Operations Centre
(RMOC). In addition, the RSGS prepares the trajectory during the comet
escort phase.
Rosetta Mission Operations Center
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The Rosetta Mission Operations Center (RMOC) is located at the
European Space Operations Center (ESOC) in Darmstadt, Germany. The
RMOC is responsible for the Spacecraft operations and all real time
contacts with the spacecraft and payload, the overall mission
planning, flight dynamics and spacecraft and payload data
distribution.
Rosetta Lander Ground Segment
------------------------------
The Rosetta Lander Ground Segment (RLGS) is made up of two
operational teams. When CNES joined the DLR consortium for developing
the Lander, it was decided to divide the RLGS into 2 centers (see
Lander Project Plan [RL-PL-DLR-97002]).
These teams are responsible for the success of the Lander operations,
to ensure that the Lander performs the science with regards to its
status, and to give the data to the PI's and suppliers.
Lander Control Center
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The Lander Control Center (LCC), located at DLR/MUSC in Koeln
(Germany), in charge of Rosetta Lander operations during the flight
segment definition, design, realization, assembly and tests.
Science Operations and Navigation Center
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The Science Operations and Navigation Center is under CNES
responsibility, located in Toulouse (France). It is responsible for
the navigation and mission analysis aspects, including separation,
landing and descent strategies and generation of the scientific
sequences.
Rosetta Scientific Data Archive
--------------------------------
All scientific data obtained during the full mission duration
remains proprietary of the PI teams and the Lander teams for a maximum
period of 6 months after they have been received from ESOC. After
this period, the scientific data products from the mission have to be
submitted to RSOC in a reduced and calibrated form such that they can
be used by the scientific community. The Archive Scientist prepares
the release of Rosetta Scientific Data Archive after reception from
the individual Rosetta instruments and after the 6 months proprietary
period.
Acronyms
--------
For more acronyms refer to Rosetta Project Glossary [RO-EST-LI-5012]
ATTC Absolute Time Telecommand
AU Astronomical Unit
CA Closest Approach
CAP Comet Acquisition Point
CAT Close Approach Trajectory
CNES Centre National d'Etudes Spatiales
COP Close Observation Phase
DLR German Aerospace Center
DSM Deep Space Manoeuver
ESA European Space Agency
ESAC European Space Astronomy Centre
ESOC European Space Operations Center
ESTEC European Space Research and Technology Center
EUV Extreme UltraViolet
FAT Far approach trajectory
FSS First Science Sequence
FUV Far UltraViolet
GCMS Gas Chromatography / Mass Spectrometry
GMP Global Mapping Phase
HGA High Gain Antenna
HgCdTe Mercury Cadmium Telluride
HIGH High Activity Phase (Escort Phase)
HK HouseKeeping
IRAS InfraRed Astronomical Satellite
IRFPA Infrared Focal Plane Array
IS Infrared Spectrometer
LCC Lander Control Center
LDL Long Debye Length
LEOP Launch and Early Orbit Phase
LOW Low Activity Phase (Escort Phase)
LTE Local Thermodynamic Equilibrium
MINC Moderate Increase Phase (Escort Phase)
MGA Medium Gain Antenna
MLI Multi Layer Insulation
MS Microscope
NNO New Norcia ground station
OCM Orbit Correction Manoeuvres
OIP Orbit Insertion Point
PI Principal Investigator
P/L PayLoad
PC Payload Checkout
PDHC Pre Delivery Calib Science
PHC Post Hibernation Commissioning
PRL Prelanding
RBD Rebounds
RF Radio Frequency
RMOC Rosetta Mission Operations Center
RLGS Rosetta Lander Ground Segment
RL Rosetta Lander
RO Rosetta Orbiter
RSGS Rosetta Science Ground Segment
RVM Rendez-vous Manoeuver
S/C SpaceCraft
SDL Separation Descent and Landing
SINC Sharp Increase Phase (Escort Phase)
SONC Science Operations and Navigation Center
SSP Surface Science Package
STR Star TRacker
SWT Science Working Team
TGM Transition to global mapping
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