SPICE is an information system that uses ancillary data to provide Solar System geometry information to scientists and engineers for planetary missions in order to plan and analyze scientific observations from space-born instruments. SPICE is developed and maintained by the Navigation and Ancillary Information Facility (NAIF) team of the Jet Propulsion Laboratory (NASA). NAIF and the European Space Agency's SPICE Service provide SPICE Training Courses on a yearly basis, these are three-day courses which are hosted either nearby Pasadena (California, USA) or nearby Madrid (Spain).
The ESA SPICE Service offers an open Short Course on SPICE aimed at scientists and engineers who want to be introduced to SPICE or who might be considering attending a complete SPICE Training.
During this course a brief introduction to SPICE will be provided and it will be followed by a practical hands-on lesson of a SPICE application based on a Mars-Express and an ExoMars2016 remote sensing observation scenario. We will also go through WebGeocalc and the SPICE-Enhanced Cosmographia 3D Visualization Software.
For more information on SPICE please visit the ESA SPICE Service (ESS) web site.
To interact during the workshop join the
OpenPlanetary forum
The agenda for the workshop will be:
- Introducing SPICE the cool way: Cosmographia.
- Cosmographia & WebGeoCalc DEMO
- Brief introduction to ESS and ESA Planetary SKDs
- Q & A
- Remote Sensing Hands-on lesson
- Q & A and close-out
This repository contains the following files:
- Jupyer Notebook introducing the use of SPICE
- Presentations given at the PWD#4 conference:
- SPICE for ESA Planetary Missions: An Update [#7003]
- Remote Sensing Lesson Directory
- NAIF Documentation for the lesson
- SPICE Kernels for the lesson
- Two Jupyter Notebooks: the original one and the working one of the workshop.
You can obtain the SPICE Toolkit in you preferred programming language here
Our recommendation for the context of this Seminar is to use the Python Wrapper SpiceyPy.
A SPICE Kernel Dataset (SKD) consists on a complete set of SPICE Kernels that cover the whole mission lifespan including reconstructed and long term predicted trajectory and orientation. The SKD has the following directory structure:
- root directory (named after the mission e.g.: ExoMars2016)
- kernels
- ck: Kernels that contain orientation for the spacecraft and some of its structures, (solar arrays, for instance).
- fk: Kernels that define reference frames needed for the Mission.
- ik: Kernels for the instruments on board the spacecraft.
- lsk: Leapseconds kernel.
- mk: Meta-kernel files (a.k.a "furnsh" files) that provide lists of kernels suitable for a given mission period.
- pck: Kernels that define planetary constants.
- sclk: Spacecraft clock coefficients kernels.
- spk: Orbit kernels, for the spacecraft and other solar system bodies.
- dsk: Digital Shape Kernels for the spacecraft extended body targets, models, etc.
- misc
- release notes: Includes the Release Notes of the SKD.
- cosmo: Includes the configuration required to run SPICE-Enhanced Cosmographia.
- other: different directories of interest.
- kernels
The SKD also include text files that help to understand the contents of every directory. Those files are named aareadme.txt.
Having the latest and most up-to-date SKD is extremely important and the ESS is putting a lot of effort on finding optimal ways to distribute the SKD.
SKDs are available as a direct download, via Git (BitBucket) and via FTP. Please note that this Git repository provides the operational subset of the full SKD which is available in the FTP.
- BitBucket Operational SKDs
- ESA SPICE FTP: ftp://spiftp.esac.esa.int/data/SPICE
- Zipped Operational ExoMars2016: ftp://spiftp.esac.esa.int/data/SPICE/ExoMars2016/misc/skd/ExoMars2016.zip, others coming soon.
In order to use Git to obtain the operational subset of the SKD, the user needs to have Git installed. In addition, Git large file system (Git LFS) needs to be installed it as well. Git LFS can be obtained here.
Once you have installed GIT LFS you need to activate it with
git lfs install
After activating Git LFS clone the repository with
git clone https://repos.cosmos.esa.int/socci/scm/spice_kernels/exomars2016.git
In order to run the SKD in SPICE outside of the mk directory of the Git repository the user needs to modify the following the PATH_VALUE variable of the meta-kernel:
PATH_VALUES = ( '..' )
It is recommended for users to make a local copy of this file. A suggestion is to rename the file to 'em16_ops_local.tm' (since this file will be ignored by Git).
Afterwards the user needs to modify the value of the PATH_VALUES keyword to point to the actual location of the SPICE data set's 'data' directory on their system. Replacing '/' with '' and converting line terminators to the format native to the user's system may also be required if this meta-kernel is to be used on a non-UNIX workstation.
ESA has a number of science missions under development and in operation that are dedicated to the study of our Solar System (i.e. MEX, Rosetta, ExoMars, BepiColombo, Solar Orbiter and JUICE). The Science Operations Centres for these missions, located at the European Space Astronomy Centre (ESAC) in Spain, are responsible for all science operations planning, data processing and archiving tasks, being the essential interface between the science instruments and the spacecraft, and with the scientific community.
From the concept study phase to the day-to-day science operations, these missions produce and use auxiliary data (spacecraft orbital state information, attitude, event information and relevant spacecraft housekeeping data) to assist science planning, data processing, analysis and archiving.
Within the Solar System scientific community, the SPICE information system is the 'de facto' standard for auxiliary data handling and geometry computations, and has been adopted and is extensively used in ESA missions. SPICE is developed and maintained by the Navigation and Ancillary Information Facility (NAIF) of the Jet Propulsion Laboratory (JPL).
The SPICE format includes definitions for orbit, attitude and event information, and the data files describing these categories are called ‘SPICE kernels’. These kernels contain sufficient information to compute derived geometrical or positional values using the existing NAIF SPICE toolkit.
For ESA missions, there are three different sources of SPICE kernels:
- The spacecraft orbit (SPK), attitude (CK) and clock correlation (SCLK) kernels, produced regularly for each mission from Mission Analysis and Flight Dynamics products and spacecraft telemetry.
- Generic kernels, such as planetary constants (PCK), leap seconds (LSK) and ephemerides (SPK), mostly provided by NAIF
- Instrument kernels (IK) and the frames specification kernel (FK), created in collaboration with the Instruments Teams
The ExoMars2016 SKD is operational and therefore it is updated with kernels generated from the periodical trajectory and orientation updates and from the relevant information obtained from housekeeping telemetry. Some updates on Instrument and S/C models might occur responding to operational demands.
The SKD contain two different types of kernels:
- Setup kernels (STK) FK, IK, PCK, LSK: they are typically text files and they are developed by ESS and are reviewed and iterated with the SGS and with the Instrument Teams when need be during the whole duration of the mission. The STKs include the following information:
- Set of Reference Frames of interest for geometry computations.
- FoV and boresight modeling for science payload.
- Study trajectory default orientation for S/C.
- Physical models for natural bodies of the mission.
- Time-varying kernels (TVK) SPK, CK, SCLK, MK: are either text or binary files and are generated with the Auxiliary Data Conversion System (ADCSng) and the source data is provided by the Flight Dynamics in terms of OEMs, AEMs and Housekeeping TM data. The TVKs incude the following information:
- Predicted attitude and predicted/reconstructed trajectory.
- OBT to UTC/CAL time conversion.
- Reconstructed trajectory and measured orientation for S/C.
- Orientation of Solar Arrays and HGA (if applicable).
- Position of scans or turn-tables or articulations of payload.
Meta-kernel (MK) file management is a critical element of any SPICE dataset. For ESA Planetary Missions the MKs of the operational SKDs are also used to control the version of the SPICE dataset in the ESA SPICE FTP server. In general missions in operations will have an "operational" MK. This MK will contain the latest SPICE kernels available for the mission including those kernels generated by ADCSng in a periodical basis. Since the periodicity of this updates ranges from hours to weeks, the MK in the Meta-Kernel directory does not have a version number and is regularly overwritten. Nevertheless in order to keep traceability and backwards compatibility with former MKs, a duplicate of every generated operational MK is stored. This duplicated MK filename is appended with a time tag and a version that corresponds to the extended version of the SKD.
Note that this duplicated MK is not available in the Git repository.
The home for SPICE at ESA is linked here. We mantain a Twitter accound where we post news and updates: SpiceESA (http://www.twitter.com/spiceesa)
Drop us a line at ESA SPICE Service, depending on our workload it might take a while before we can give you an answer.
The ESA SPICE Service is present in the OpenPlanetary Slack channel
In order to be keep up to date with the latest SKD releases, TVK generation and overall SKD related issues you can subscribe to a given project mail list
- ExoMars2016 mail list
- Mars-Express mail list
- Venus-Express mail list
- JUICE mail list
- BepiColombo mail list
- Rosetta mail list
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 Python (SpiceyPy), and the user can choose any one that suits him/her.
The SPICELIB routine FURNSH, CSPICE function furnsh_c, icy routine cspice_furnsh, mice routine cspice_furnsh and SpiceyPy routine furnsh load a kernel file into the kernel pool as shown below.
CALL FURNSH ( 'kernel_name' )
furnsh_c ( "kernel_name" );
cspice_furnsh, 'kernel_name'
cspice_funsh( 'kernel_name' );
spiceypy.furnsh( 'kernel_name' )