| DATA_SET_DESCRIPTION |
1. SPICE System Overview
=====================
SPICE data contain geometric and other ancillary information needed
to recover the full value of science instrument data. In particular,
SPICE kernels provide spacecraft and planetary ephemerides,
instrument mounting alignments and spacecraft orientation. Data
needed for relevant time conversions is also included.
SPICE was designed by the Navigation and Ancillary Information
Facility (NAIF) to aid scientists and engineers with ancillary and
engineering data. This data comes from a wide range of sources such
as the spacecraft, the mission control center and the designers of
the spacecraft and its instruments.
The ancillary data comprises information on data acquisition;
position and orientation of the spacecraft at the time of
acquisition; information on the target, such as location, shape and
orientation; reference frame specifications and time conversion
data.
The primary SPICE data sets are often called 'kernels' or 'kernel
files'. These kernels are composed of ancillary information, which
has been created in such a way as to allow easy access and correct
usage by the space science and engineering communities.
In addition to the kernels, there is software provided, known as the
SPICE Toolkit, along with standards, documentation and software
support. The SPICE Toolkit and documentation can be found at:
http://naif.jpl.nasa.gov/naif/
The SPICE Toolkit was freely offered to the worldwide space science
and space mission engineering communities at the time this data set
was released. The few rules governing its use are posted on the
''Rules'' page of the NAIF website:
https://naif.jpl.nasa.gov/naif/rules.html
SPICE is used on a number of space missions, such as ESA's Mars
Express, SMART-1, Venus Express, ExoMars2016, BepiColombo,
Solar Orbiter and Rosetta missions, and all of NASA's solar system
exploration missions. The SPICE system has been produced and is
maintained by Caltech's Jet Propulsion Laboratory under contract to
the U.S. National Aeronautics and Space Administration.
For an additional explanation of the SPICE system, please consult
SPICE_INST.CAT.
2. Data Producers and Other Key Personnel
======================================
The Rosetta SPICE data set has been produced by
Barthelemy, M. (RSSD/ESA)
Costa Sitja, M. (NAIF/JPL)
Escalante, A. (ESAC/ESA)
Valles, R. (ESAC/ESA)
Grieger, B. (ESAC/ESA)
Semenov, B. (NAIF/JPL)
Vazquez, J.L. (RSSD/ESA)
Zender, J. (RSSD/ESA)
and archived by
Costa Sitja, M. (NAIF/JPL)
Escalante, A. (ESAC/ESA)
Valles, R. (ESAC/ESA)
3. The Rosetta SPICE data set
=========================
NOTE: This data set incorporates all kernels from and fully
supersedes the ROS-E/M/A/C-SPICE-6-V1.0 data set that was originally
produced in 2007, released in 2010 and updated in 2011.
The Rosetta SPICE data set consists of SPICE kernels of several
types, organized as follows:
* CK: These kernels contain information about orientation of the
spacecraft and its articulating structures as well as orientation
of the natural bodies that cannot be represented by standard IAU
rotation models (e.g. the comet 67P/C-G). More information on CKs
in this data set is provided in CKINFO.TXT.
* DSK: These kernels contain information about the shape of the
Rosetta mission targets. More information on DSKs in this data set
is provided in DSKINFO.TXT.
* FK: These kernels contain definitions of and specifications of
relationships between reference frames (coordinate systems).
Among the frames kernels included, there are kernels that specify
reference frames related to the earth, mission targets, and the
spacecraft and its instruments. More information on FKs in this
data set is provided in FKINFO.TXT.
* IK: These kernels contain instrument information, such as field of
view or internal timing specifications. There are IKs provided
for most of the Rosetta orbiter and lander instruments. More
information on IKs in this data set is provided in IKINFO.TXT.
* LSK: These kernels contain a table with the leapseconds used to
convert between ET and UTC. If there are multiple LSKs in this
data set, the latest kernel supersedes the previous ones. More
information on LSKs in this data set is provided in LSKINFO.TXT.
* PCK: These kernels provide information about the solar system
bodies orientation and shape, and possibly parameters for
gravitational, atmospheric or rings models. The data set contains
PCKs for the planets, their satellites, the asteroids Lutetia and
Steins, and the comet 67P/C-G. More information on PCKs in this
data set is provided in PCKINFO.TXT.
* SCLK: These kernels contain data needed for conversion between ET
and spacecraft clock. If there are multiple SCLKs in this
data set, the latest kernel supersedes the previous ones. More
information on SCLKs in this data set is provided in SCLKINFO.TXT.
* SPK: These kernels contain ephemeris data (position and velocity)
of the spacecraft and solar system bodies. The data set provides
kernels with such information for the planets, the Sun, the Moon,
the comet 67P/C-G, the two fly-by asteroids Lutetia and Steins,
the fly-by comet (Tempel 1), ground tracking stations, and the
Rosetta orbiter and lander spacecraft. More information on SPKs
in this data set is provided in SPKINFO.TXT.
3.1 - Origin of the kernels.
a) Generic kernels such as PCKs, LSKs and some of the SPKs are
provided by NAIF.
b) FKs and IKs have been developed NAIF in collaboration with the
instrument teams and ESAC/ESA.
c) The majority of SPKs and CKs containing mission specific data for
the spacecraft and for the mission targets as well as SCLKs
were generated by ESAC/ESA from ancillary data files produced
by ESOC.
d) DSKs of natural bodies were generated by NAIF from other format
shape model files produced by ESOC and by science instrument teams.
The DSKs of the Abydos region and spacecraft structures have been
produced by the ESA SPICE Service.
3.2 - Creation of SPK, CK and SCLK kernels from ESOC Ancillary
Data.
ESOC provided orbit and attitude data in the form of text files.
These products were the source of the CK and SPK kernels.
ESOC generated time correlation data records and stored them in
the telemetry server. These records were the source for the SCLK
kernel.
An automated system, called ADCS (Automatic Data Conversion
System) was responsible for the generation of CK, SPK and SCLK
kernels from the ESOC flight dynamics data file products and
telemetry server SCLK records. ADCS detected when a new product
was generated or a new time correlation packet was available, and
ran a series of processes in order to create the proper kernels.
ADCS used the SPICE Toolkit in order to fulfill its task. It ran
on a server physically located at ESTEC until December 2007;
after that date, the server was located at ESAC.
3.3 - Using the SPICE kernels.
At least a basic knowledge of the SPICE system is needed in order
to use these kernels. The SPICE Toolkit provides versions in
Fortran (SPICELIB), C (CSPICE), IDL (icy), Matlab (Mice), and
Java (JNISpice) and the user can choose any one that suits
him/her.
The SPICE routine FURNSH can be used to load a kernel file into a
SPICE-based application to make kernel's data usable with SPICE
APIs.
In the case when two or more kernel files contain data
overlapping in time for a given object, for binary kernels, the
file loaded last takes precedence.
If two (or more) text kernels assign value(s) using the '='
operator to identical keywords, the data value(s) associated with
the last loaded occurrence of the keyword are used -all earlier
values have been replaced with the last loaded value(s).
3.4 - Meta-kernels
Metakernel files, called 'ROS_Vvv.TM' and 'ROS_WITH_DSK_Vvv.TM',
can be found under the ``EXTRAS/MK/'' directory in this data set.
This file can be used with a SPICE-based application running on a
UNIX workstation to load Rosetta SPICE data provided in this data
set together (note that the logical path provided in the PATH_VALUES
keyword and pointing to the volume root directory should be changed
to the actual path of the volume root directory on the system where
the volume is mounted).
When there are two or more kernels that cover the same time
interval (as is the case here for the .BSP and .BC kernels)
the last kernel loaded is the one used by the SPICE software
for computations in the interval or overlap.
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