| DESCRIPTION |
The majority of the text in this file
was extracted from the Juno Mission Plan Document, S. Stephens, 29 March
2011.[JPL D-35556]
Mission Overview
================
Juno launched on 5 August 2011. The spacecraft uses a deltaV-EGA trajectory
consisting of a two part deep space maneuver on 30 August and 14 September
2012 followed by an Earth gravity assist on 9 October 2013 at an altitude of
559 km. Jupiter arrival is on 5 July 2016 using two 53.5-day capture orbits
prior to commencing operations for a 1.3-(Earth) year-long prime mission
comprising 32 high inclination, high eccentricity orbits of Jupiter. The
orbit is polar (90 degree inclination) with a periapsis altitude of
4200-8000 km and a semi-major axis of 23.4 RJ (Jovian radius) giving an
orbital period of 13.965 days. The primary science is acquired for
approximately 6 hours centered on each periapsis although fields and
particles data are acquired at low rates for the remaining apoapsis portion
of each orbit.
Currently, 5 of the first 7 periapses are dedicated to microwave radiometry
of Jupiter's deep atmosphere with most of the remaining orbits dedicated to
gravity measurements to determine the structure of Jupiter's interior. All
orbits will include fields and particles measurements of the planet's
auroral regions. Juno is spin stabilized with a rotation rate of 2
rotations per minute (RPM). For the radiometry orbits the spin axis is
precisely perpendicular to the orbit plane so that the radiometer fields of
view pass through the nadir. For gravity passes, the spin axis is aligned
to the Earth direction, allowing for Doppler measurements through the
periapsis portion of the orbit. The orbit plane is initially very close to
perpendicular to the Sun-Jupiter line and evolves over the 1.3-year mission.
Generally, data acquired during the periapsis passes are recorded and played
back over the subsequent apoapsis portion of the orbit, although some data
can be downlinked during the gravity passes.
Juno's instrument complement includes Gravity Science using the X and Ka
bands to determine the structure of Jupiter's interior; magnetometer
investigation (MAG) to study the magnetic dynamo and interior of Jupiter as
well as to explore the polar magnetosphere; and a microwave radiometer (MWR)
experiment covering 6 wavelengths between 1.3 and 50 cm to perform deep
atmospheric sounding and composition measurements. The instrument
complement also includes a suite of fields and particle instruments to study
the polar magnetosphere and Jupiter's aurora. This suite includes an
energetic particle detector (JEDI), a Jovian auroral (plasma) distributions
experiment (JADE), a radio and plasma wave instrument (Waves), an
ultraviolet spectrometer (UVS), and a Jupiter infrared auroral mapping
instrument (JIRAM). The JunoCam is a camera included for education and
public outreach. While this is not a science instrument, we plan to capture
the data and archive them in the PDS along with the other mission data. The
MAG investigation consists of redundant flux gate magnetometers (FGM) and
co-located advanced stellar compasses (ASC). The ASCs are provided by the
Danish Technical University under an effort led by John Jorgenson.
Scott Bolton is the Juno Principal Investigator. The Science Team members
responsible for the delivery and operation of the instruments are listed
below:
Instrument Acronym Lead Co-I
---------------------------------------------- -------- ---------
Gravity Science GRAV Folkner
Magnetometer MAG Connerney
Microwave Radiometer MWR Janssen
Jupiter Energetic Particle Detector Instrument JEDI Mauk
Jovian Auroral Distributions Experiment JADE McComas
Radio and plasma wave instrument Waves Kurth
Ultraviolet Imaging Spectrograph UVS Gladstone
Jovian Infrared Auroral Mapper JIRAM Adriani
Juno color, visible-light camera JUNOCAM Hansen
Mission Phases
==============
LAUNCH
------
The Launch phase starts at L-40 min (Launch-40 min), and covers the
interval from launch, through initial ground station acquisition, until
the establishment of a pre-defined, stable, and slowly changing Sun-
pointed attitude when cruise attitude control algorithms and ephemerides
can be used. The end of the Launch phase is determined by post-launch
health and safety assessments. The boundary is at L+3 days, after initial
acquisition and after confirmation that the Flight System is safe and in
a power-positive, thermally stable, and commandable attitude.
Target Name : N/A
Mission Phase Start Time : 2011-08-05 (2011-217)
Mission Phase Stop Time : 2011-08-08 (2011-220)
INNER CRUISE 1
--------------
The Inner Cruise 1 phase lasts from post-Launch establishment of a
pre-defined and stable Sun-pointed attitude when cruise attitude control
algorithms and ephemerides can be used, until after initial spacecraft and
instrument checkouts have been performed and the spacecraft has gotten far
enough from the Sun to allow Earth-pointing instead of Sun-pointing. TCM 1
(the first planned trajectory correction maneuver) was deemed not
necessary, hence, was not executed. The phase spans the interval from L+3
to L+66 days.
Target Name : SOLAR_SYSTEM
Mission Phase Start Time : 2011-08-08 (2011-220)
Mission Phase Stop Time : 2011-10-10 (2011-283)
INNER CRUISE 2
--------------
The Inner Cruise 2 phase spans the period from L+66 days until L+663
days. The Deep Space Maneuvers (DSMs) occur during this phase, near
aphelion of Juno's first orbit about the Sun, on the way to Earth Flyby
and then Jupiter. There is increased DSN (Deep Space Network) coverage
associated with the DSMs and a cleanup TCM. DSMs 1 and 2 occur on
2012-08-30 and 2010-09-14.
Target Name : SOLAR_SYSTEM
Mission Phase Start Time : 2011-10-10 (2011-283)
Mission Phase Stop Time : 2013-05-29 (2013-149)
INNER CRUISE 3
--------------
The Inner Cruise 3 phase spans the interval from L+663 days to L+823
days. The duration of this cruise phase is 160 days. Featured in this
phase is Earth Flyby (EFB), which gives Juno a gravity assist (providing
7.3 km/s of deltaV) on its way to Jupiter. It occurs as the spacecraft is
completing one elliptical orbit around the Sun and includes perihelion.
Three TCMs were planned before EFB (the last of which was deemed not
necessary) and one after EFB. There is increased DSN coverage associated
with the 4 maneuvers and EFB. The Inner Cruise 3 phase is focused on
performing the required maneuvers, as well as an integrated operations
exercise around Earth Flyby, subject to Flight System constraints.
Closest approach to Earth occurs on 2013-10-09 at 19:21 UTC.
Target Name : EARTH, SOLAR_SYSTEM
Mission Phase Start Time : 2013-05-29 (2013-149)
Mission Phase Stop Time : 2013-11-05 (2013-309)
Earth Closest Approach : 2013-10-09T19:21 (2013-282)
OUTER CRUISE
------------
The Outer Cruise phase lasts from L+823 days until the start of Jupiter
Approach at Jupiter Orbit Insertion (JOI)-6 months (JOI-182 days or
L+1614 days). The duration of this cruise phase is 791 days, which is
over 2 years.
Target Name : SOLAR_SYSTEM
Mission Phase Start Time : 2013-11-05 (2013-309)
Mission Phase Stop Time : 2016-01-05 (2016-005)
JUPITER APPROACH
----------------
The Jupiter Approach phase lasts the final 6 months of cruise before
Jupiter Orbit Insertion and is an opportunity for final Flight System and
instrument checkouts as well as science observations to start exercising
the ground system and Flight System, although orbit insertion preparations
limit instrument activities close to JOI. There are more frequent
maneuvers approaching JOI, starting with a TCM at JOI-5 months, and
correspondingly increasing DSN coverage. The 178-day Jupiter Approach
phase is preceded by a 26-month Outer Cruise phase. Jupiter Approach
starts 3 months after the project is fully staffed up in preparation for
JOI and the 1.3 years of science orbits. The phase ends at JOI-4 days,
which is the start of the JOI critical sequence.
Target Name: : JUPITER, SOLAR_SYSTEM
Mission Phase Start Time : 2016-01-05 (2016-005)
Mission Phase Stop Time : 2016-07-01 (2016-183)
JUPITER ORBIT INSERTION
-----------------------
The JOI phase encompasses the JOI critical sequence. It begins 4 days
before the start of the orbit insertion maneuver and ends 1 hour after the
start. JOI, the second critical event of the mission, occurs at closest
approach to Jupiter, and slows the spacecraft enough to let it be captured
by Jupiter into a 53.5-day orbit and set up the geometry for the 14-day
science orbits. A cleanup burn at JOI+8.6d during the Capture Orbits
phase is required to clean up JOI maneuver execution errors. DSN coverage
is continuous during the JOI phase.
Target Name : N/A
Mission Phase Start Time : 2016-07-01 (2016-183)
Mission Phase Stop Time : 2016-07-05 (2016-187)
Perijove 0 : 2016-07-05T02:47:38 (2016-187)
CAPTURE ORBITS
--------------
The Capture Orbits phase starts at JOI+1h, after the end of the JOI
critical sequence, and ends at PRM-5.25d, when instruments are off in
preparation for the PRM maneuver. Between the two 53.5d capture orbits
is PJ1 (Perijove 1), at which no maneuver is planned so it can be used as
the first opportunity for science close to Jupiter and an opportunity to
test the performance of the instruments in the Jupiter environment. A JOI
cleanup maneuver at JOI+8.6d is required to clean up JOI maneuver
execution errors, while additional maneuvers near the first apojove
following JOI and at PJ1+14d ensure the timing of PJ1 and the large PRM
burn at perijove of the following orbit. Solar conjunction occurs after
apojove of the second capture orbit. DSN coverage remains continuous
until the JOI+8.6d maneuver, then remains at elevated levels throughout
the two capture orbits, and is continuous again around PJ1 and before PRM.
Instruments are on for most of the Capture Orbits, and there are routine
checkouts and science observations.
Target Name : JUPITER, SOLAR_SYSTEM
Mission Phase Start Time : 2016-07-05 (2016-187)
Mission Phase Stop Time : 2016-10-14 (2016-288)
Perijove 1 : 2016-08-27T12:51:20 (2016-240)
PERIOD REDUCTION MANEUVER
-------------------------
The Period Reduction Maneuver phase starts at PRM-5.25d, and ends at
PRM+50h, coinciding with the instrument keepout zone for the maneuver (no
science observations are planned during this phase). The burn at PJ2
(Perijove 2) is designed to accomplish a decrease in the period and size
of the orbit, thus the name Period Reduction Maneuver (PRM). PRM requires
a cleanup maneuver in the following orbit to ensure proper timing for
longitude coverage during the Science Orbits phase. DSN coverage is
continuous from PRM-14d until PRM+5d.
Target Name : N/A
Mission Phase Start Time : 2016-10-14 (2016-288)
Mission Phase Stop Time : 2016-10-21 (2016-295)
Perijove 2 : 2016-10-19T18:11:07 (2016-293)
ORBITS 2-3
----------
The Orbits 2-3 phase starts at PRM+50h, after the end of the instrument
keepout zone for the Period Reduction Maneuver, and near the beginning of
the first 14-day orbit. It ends at PJ4-1d, which is the start of the
first activity period (MWR AP4) in the Science Orbits. As such, the Orbits
2-3 phase includes most of the last half of Orbit 2 (PJ2 to AJ2) and all
of Orbit 3 (AJ2 to AJ3). DSN coverage is continuous from the start of the
phase until PRM+5d, and then follows a pattern similar to that used for
the Science Orbits template. Instrument checkouts after PRM and science
observations during the rest of Orbit 2 and in Orbit 3 are planned.
Target Name : JUPITER
Mission Phase Start Time : 2016-10-21 (2016-295)
Mission Phase Stop Time : 2016-11-15 (2016-320)
Perijove 3 : 2016-11-02T17:52:29 (2016-307)
SCIENCE ORBITS
--------------
The Science Orbits phase includes Orbit 4 through Orbit 36. Orbit N is
defined from apojove (AJ) N-1 through apojove N, and includes perijove
(PJ) N. Orbit numbering starts before the Science Orbits phase. JOI
occurs at PJ0, so Orbit 0 lasts from PJ0 through AJ0 (including a JOI
cleanup maneuver at JOI+8.6d). Orbit 1 includes PJ1, and runs from AJ0
through AJ1. Orbit 2 includes PJ2 (and PRM at PJ2), and runs from AJ1
through AJ2. Orbit 0, Orbit 1, and the first half of Orbit 2 together
contain the two 53.5-day capture orbits. Orbit 3 includes PJ3 (and the
PRM cleanup maneuver at PJ3+6h), and runs from AJ2 through AJ3. Early
orbital science is baselined in Orbits 0, 1, 2, and 3, except for JOI and
PRM keepout zones. Orbit 4 is the first science orbit. It includes PJ4
(and the first OTM at PJ4+7.5h), and runs from AJ3 through AJ4. The last
science orbit is Orbit 36. It is bookkept as an extra science orbit,
since the mission uses Orbits 4 through 35 to obtain 32 perijoves with
MAG and other data that meet Level-1 baseline science requirements. Small
(up to 8 m/s) orbit trim maneuvers (OTMs) are planned after each set of
perijove science observations, at PJ+4h, PJ+6h, or PJ+7.5h in Orbits 4
through 35, to target the perijove longitude required for science
observations in the next orbit. There is no need for an OTM after PJ36. A
deorbit maneuver (deterministic deltaV = 77 m/s) is planned near AJ36.
We distinguish activity periods from orbits. Orbits are used to refer to
the mission design and navigation strategy (e.g., Nav data cutoffs, which
occur near AJ orbit boundaries, and trajectory events), while activity
periods are used to describe science and mission operations (e.g.,
sequences and data flow). An activity period (AP) runs from one PJ-1d to
the next PJ-1d. Each AP is defined by the number of the PJ science pass
it contains, and the type (MWR or GRAV). AP2 and AP3 are the first 14-day
activity periods (differing slightly from science orbits activity
periods), and run from PJ2-1d through PJ3-1d and PJ3-1d through PJ4-1d.
AP3 is followed by the first activity period during the Science Orbits,
AP4 (an MWR type), from PJ4-1d through PJ5-1d. The Science Orbits phase
begins at the start of AP4, and continues through AP36, which ends early,
at AJ36-1h, before the deorbit burn in the Deorbit phase.
Radiation accumulation increases substantially as the orbital line of
apsides rotates and perijove latitude increases from 3 degrees at JOI to
36 degrees at PJ36. There are currently no plans for an extended mission.
Target Name : JUPITER
Mission Phase Start Time : 2016-11-15 (2016-320)
Mission Phase Stop Time : 2018-02-13 (2018-044)
Perijove 4 : 2016-11-16T16:54:46 (2016-321)
Perijove 5 : 2016-11-30T15:52:21 (2016-335)
Perijove 6 : 2016-12-14T14:49:58 (2016-349)
Perijove 7 : 2016-12-28T13:47:35 (2016-363)
Perijove 8 : 2017-01-11T13:59:37 (2017-011)
Perijove 9 : 2017-01-25T12:57:12 (2017-025)
Perijove 10 : 2017-02-08T11:54:47 (2017-039)
Perijove 11 : 2017-02-22T10:52:21 (2017-053)
Perijove 12 : 2017-03-08T09:12:44 (2017-067)
Perijove 13 : 2017-03-22T08:10:19 (2017-081)
Perijove 14 : 2017-04-05T07:07:53 (2017-095)
Perijove 15 : 2017-04-19T06:05:27 (2017-109)
Perijove 16 : 2017-05-03T06:17:26 (2017-123)
Perijove 17 : 2017-05-17T05:14:57 (2017-137)
Perijove 18 : 2017-05-31T04:12:29 (2017-151)
Perijove 19 : 2017-06-14T03:10:03 (2017-165)
Perijove 20 : 2017-06-28T03:40:40 (2017-179)
Perijove 21 : 2017-07-12T02:38:12 (2017-193)
Perijove 22 : 2017-07-26T01:35:46 (2017-207)
Perijove 23 : 2017-08-09T00:33:19 (2017-221)
Perijove 24 : 2017-08-23T00:08:07 (2017-235)
Perijove 25 : 2017-09-05T23:05:44 (2017-248)
Perijove 26 : 2017-09-19T22:03:21 (2017-262)
Perijove 27 : 2017-10-03T21:00:55 (2017-276)
Perijove 28 : 2017-10-17T20:35:43 (2017-290)
Perijove 29 : 2017-10-31T19:33:14 (2017-304)
Perijove 30 : 2017-11-14T18:30:45 (2017-318)
Perijove 31 : 2017-11-28T17:28:16 (2017-332)
Perijove 32 : 2017-12-12T17:02:53 (2017-346)
Perijove 33 : 2017-12-26T16:00:20 (2017-360)
Perijove 34 : 2018-01-09T14:57:50 (2018-009)
Perijove 35 : 2018-01-23T13:55:18 (2018-023)
Perijove 36 : 2018-02-06T12:52:47 (2018-037)
DEORBIT
-------
The Deorbit phase occurs during the final perijove-to-perijove orbit of
the mission. The 7-day phase starts several days after the Orbit 36
perijove science pass (part of the extra orbit) at AJ36-1h, before the
start of the apojove deorbit maneuver (by which time we hope to have all
or most of the PJ36 data on the ground). It continues through AJ36, and
ends with Impact into Jupiter at PJ37. In order to meet planetary
protection requirements and ensure that we do not impact Europa (as well
as Ganymede and Callisto), the spacecraft performs a deorbit maneuver near
apojove that reduces our orbital velocity and sends us to a perijove below
Jupiter's cloud tops. The mean burn deltaV of 77 m/s is the largest
maneuver of the mission after the 4 main engine maneuvers, and is planned
to be performed on RCS (Reaction Control System) thrusters (deltaV to
Earth angle, ELA ~ 70 degrees). The timing of the burn is not mission
critical; a contingency delayed execution can occur several days around
and following apojove if necessary. Impact into Jupiter marks End of
Mission (EOM).
Target Name : JUPITER
Mission Phase Start Time : 2018-02-13 (2018-044)
Mission Phase Stop Time : 2018-02-20 (2018-051)
Perijove 37 : 2018-02-20T11:39:44 (2018-051)
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