The .SSC files below have Unix-style bare line-feeds as the record delimiters. The Windows versions of Celestia, Emacs and Wordpad read and display the files just fine, but they aren't so readable if you use Notepad. Sorry.
Object | Orbit Files | Comments |
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Cassini-Huygens Saturn probe |
Cassini JPL home page
See also:
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Obital parameters were obtained from the Horizons Ephemeris System at http://ssd.jpl.nasa.gov/?horizons, using its telnet or e'mail interface. |
cassini.zip (140KB, 6Dec2002) Contains the following files: |
This .ZIP archive file includes all of the "elliptical orbit"
.SSC files below as well as Chris' cassini.xyz and a .SSC file to invoke it.
Note: the xyz file has been updated by Chris to include an appropriate number of samples during the Earth flyby. |
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Below are the equivalent elliptical orbits for several segments of the probe's path through the solar system, together showing how the trajectory was modified by using gravity assists at Venus, Earth and Jupiter. This ignores the trajectory adjustments made using the probe's own propulsion system. |
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Cassini-19980115.ssc (1KB, 15Oct2002) |
for 15-Jan-1998, travelling between Earth and Venus. | |
Cassini-19981201.ssc (1KB, 15Oct2002) |
for 01-Dec-1998, travelling between Venus and Venus | |
Cassini-19990719.ssc (1KB. 15-Oct-02) |
for 19-Jul-1999, travelling between Venus and Earth | |
Cassini-2000.ssc (1KB, 10-Oct-02) |
for 01-Jan-2000, travelling between Mars and Jupiter: near Masursky observation. | |
Cassini-2002.ssc (1KB, 10-Oct-02) |
for 10-Oct-2002, travelling between Jupiter and Saturn. | |
Cassini-ss.ssc (1KB, 4dec02) |
for 30June2004 & 1July2004: Saturn insertion, 2 Heliocentric elliptical orbits | |
Cassini-s.ssc (1KB, 4dec02) |
for 1July2004: just after Saturn orbital insertion, Saturn elliptical orbits. | |
(150KB 6Dec2002)
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For the interval 1997-Oct-15 10:30 to 2006-Jan-15 10:30 UDT.
This version of Cassini's xyz trajectory contains position samples every two days for most of the trajectory. However it includes much more frequent samples of the spacecraft's path for each of the important encounters: Earth launch, the two Venus gravity assist flybys, the Earth gravity assist flyby, the encounter with asteroid (2685) Masursky, the Jupiter gravity assist flyby, the Phoebe flyby, and the Saturn orbital insertion. Each of those events is sampled 100/day for +/- two days. Several additional samples are included at the time of closest approach to Earth to improve the accuracy of Celestia's display. Celestia v1.3.2pre8 (and later versions) includes an up-to-date xyz trajectory for Cassini, so I won't be trying to improve the trajectory provided here. Celestia's trajectory for Cassini can be downloaded from http://cvs.sourceforge.net/viewcvs.py/celestia/celestia/data/cassini.xyz |
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cassini-es.ssc
(1.5KB 3Dec02) |
This .SSC file contains the orbital elements for the time of Cassini's closest approach to the Earth during the Earth gravity assist. If you set Celestia's time to 18-Aug-1999 03:28 UT and follow Cassini, tracking Earth, your field of view will be filled by the South Pacific as you go hurtling by. | |
cassini-040611.ssc | Cassini's Heliocentric elliptical orbital paramenters for the time of the Phoebe flyby. | |
Asteroid (2685) Masursky |
2685.ssc (1.5K, 16-Oct-02) |
NASA Press Release
LPL's CICLOPS (Cassini Imaging Central Laboratory for OPerations) description of the encounter. The asteroid has been set to be of Class "moon" to simplify comparisons of its orbit and Cassini's. |
Phoebe |
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These files specify the Heliocentric cartesian coordinates for Phoebe
for slightly more than one of its orbital periods at two day sample
intervals. It includes 100 samples/day for +/- 2 days around the
time of Cassini's flyby.
These coordinates were obtained from Horizons.
Using these xyz trajectories, Celestia shows the flyby to be at 2004-Jun-11 19:35:20 UTC at a distance of about 2,124 km. According to the JPL Web page http://www.nasa.gov/mission_pages/cassini/media/cassini-061204-b.html Closest approach was about 2,068 km. Apparently it happened at 13:56 Pacific time (19:56 UTC) on 11 June, 2004. The elliptical orbital elements used by Celestia v1.2.5 through v1.3.2 placed Phoebe 180 degrees away in its orbit. However, the elliptical orbital elements used by Celestia v1.4.0 place Phoebe at a distance of 3,220 km at 19:36 UTC. |
Some significant events:
Ref: http://www.jpl.nasa.gov/news/fact_sheets/cassini.pdf (Aug, 2001)
Ref: http://esapub.esrin.esa.it/bulletin/bullet92/b92kohlh.htm (Nov. 1997)
Ref: http://quest.arc.nasa.gov/saturn/qa/new/Location_of_orbit_injection.txt (as of 12 Jan 2000)
Ref: http://www.spacedaily.com/news/cassini-01e2.html (May 15, 2002)
Object | Orbit Files | Comments |
---|---|---|
Ulysses Solar probe | Ulysses JPL home page | Orbital positions were obtained from the Horizons Ephemeris System using its telnet interface. |
Ulysses.ssc (1.5KB: 31-Oct-2002) |
This .SSC file contains the elliptical orbital elements as predicted by Horizons for October 31st, 2002. and for May 1st, 1996, when Ulysses observed the tail of Comet Hyakutake. (See elsewhere.) Ulysses' orbital insertion trajectory is not included. | |
Comet C/1996 B2 Hyakutake |
hyakutake-horizons.ssc
(1.5KB: 30-Oct-2002) |
Two sets of Horizons' orbital parameters
for 28-October-2002 and for 26-March-1996, (~closest approach to Earth). |
Additional notes:
Object | Orbit Files | Comments |
---|---|---|
Stardust Cometary Probe | Stardust JPL home page |
Obital positions were obtained from the
Horizons Ephemeris System at
http://ssd.jpl.nasa.gov/horizons.html, using its
telnet and e'mail interfaces.
Stardust's orbit has been deleted and restored to Horizons at least once due to accuracy problems. As of 25 June 2004, ephemeris data is not available for before 2002-NOV-20 01:00:00. |
stardust.zip (77KB, 25-june-2004) |
This .ZIP archive file includes .SSC and xyz files for Stardust, the asteroid Annefrank and Comet 81P/Wild 2. | |
stardust-xyz.ssc (1KB, 1-Nov-2002) stardust.xyz (130KB, 25-June-2004) |
This .SSC invokes Stardust's xyz trajectory.
The TXYZ vectors of Stardust's trajectory are from launch to return to Earth as predicted by JPL's Horizons ephemeris server, sampled at two day intervals for most of the trajectory. For better tracking, there are 300 samples during the three closest days of each of the flybys of Earth, Annefrank and Wild 2. The Horizons' database of Stardust's trajectory had not been updated since 2001, so the details of the Annefrank flyby are not quite right. Stardust's xyz trajectory incorporates updated trajectory points for the January 2nd flyby of 81P/Wild-2 flyby, obtained from Horizons on 25-June-2004. |
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Asteroid (5535) Annefrank |
annefrank.ssc (1.5KB, 7Nov2002) |
Radius = 3km (per NASA press release)
Albedo "darker than expected" (0.05 guestimated)
See also the NASA press release and below for more information about the Annefrank flyby coordinates. |
Comet 81P/Wild 2 |
wild-2.ssc (1.5KB, June 25, 2004) |
For more information about Wild 2, see elsewhere in the cometary section. |
After increasing the number of xyz samples for Stardust's trajectory from 1 every 2 days to 100 per day during the time of closest approach, Celestia v1.2.5pre6 showed the minimum distance between the probe and the asteroid to be a little more than 600km at about 04:43 on 2-Nov-2002. Using the Stardust's Keplerian orbital parameters for that date results in a distance slightly less than 600km. This is quite a bit less than the Web site's prediction of 3000km.
When I inquired, I learned that the Horizons' database of Stardust's trajectory had not been updated since 2001, so the details of the Annefrank flyby are not quite right.
After upgrading to Celestia v1.2.5pre7, the minimum separation improved to 1,500km, at about 04:35 UTC, SCET (SpaceCraft Event Time). For a distance of about 2.25 AU from the Earth, light travel time is about 18.6 minutes, so that would be about 04:54 ERT (Earth Received Time). NASA's Web pages often, but not always, specify their time estimates in terms of ERT. It isn't clear if that's the case here.
Using the Stardust's .xyz trajectory, Celestia's closest positions for the Earth/Moon flyby also seem to be off somewhat, and seem to be more accurate for the Moon than for the Earth flyby.
Object | Data Files | Comments |
---|---|---|
INTEGRAL Gamma Ray satellite. |
INTEGRAL Gamma Ray satellite ESA home page
(INTErnational Gamma-Ray Astrophysics Laboratory) Note: The INTEGRAL Web site includes a link to ESA's "Satellites in Orbit" script. It generates links to information about various spacecraft, including INTEGRAL. These pages include Javascript and 3D Flash displays of models of the satellites. Unfortunately, direct links to those pages do not work. Integral's orbit has changed significantly in the years since it was launched. See http://www.sciops.esa.int/index.php?project=INTEGRAL&page=index At the bottom of their page is a link to a movie created using Celestia to show the evolution of the orbit.
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See also: INTEGRAL Science Operations Centre |
integral.zip (1MB, 6Feb2003)
When decompressed into your Celestia directory, ZIP should put the .SSC and .3DS files into the /extras/ /models/ subdirectories.
integral-13.zip (1MB, 25Mar2003)
/extras/ directory. It will create a subdirectory named
/integral/ containing the INTEGRAL.SSC file and
/models/ subdirectory.
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![]() INTEGRAL as shown by Celestia (This is a link to a much larger image.) |
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integral.ssc (1.5KB; 6Feb2003)
updated to display the model integral.3ds. See below. This file should go in your Celestia/extras directory. |
Orbital paramters as obtained from JPL's
Horizons Ephemeris System
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Integral satellite model courtesy of ESA | |
"Jestr" was kind enough to create colored versions of the model.
They're available on the
Celestia Motherlode:
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![]() INTEGRAL as shown by Celestia (This is a link to a much larger image.) |
Object | Data Files | Comments |
---|---|---|
Rosetta Orbiter | ESA's Rosetta home page | Trajectory information is now available: due to Ariane-5 booster problems, the Rosetta's launch was postponed until 2 March 2004. See http://sci.esa.int/content/news/index.cfm?aid=1&cid=1&oid=31326. |
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Rosetta's Heliocentric trajectory, including destination comet and asteroid orbits.
Provided by ESA with minor edits by S.Ball. |
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Geocentric trajectory of Rosetta's first Earth flyby.
Provided by ESA with minor edits by S.Ball. |
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A model of the Rosetta spacecraft by J. LeBoutet for use with Celestia is available at http://j.leboutet.free.fr/celestia/models/rosetta.zip |
It's interesting to compare Celestia's predictions of the encounters of November 4th, 2002, (PST) with those published by NASA. Here are the pre-encounter predictions, taken from http://galileo.jpl.nasa.gov/news/thiswk/today021104.html
Event | ERT | SCET |
---|---|---|
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|
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Flyby of Io at 45,250km | 7:41PM 4-Nov | 18:57 = 02:57 5-Nov |
Flyby of Amalthea at 160km. | 11:02:28 | 22:18:28 = 06:18:28 |
Enter Jupiter's shadow
(Sun disappears behind planetary limb) |
11:14 | 22:30 = 06:30 |
Leave view of Earth | 11:25 | 22:41 = 06:41 |
peri-Jove at ~71,500km above cloudtops | ~00:08 5-Nov | 23:24 = 07:24 |
Leave Jupiter's shadow
(Sun reappears) |
~00:13 | 23:29 = 07:29 |
Visible from Earth | ~00:23 | 23:39 = 07:39 |
Cross Io's orbit outbound | 4:15AM | 03:21 = 11:21 |
According to the note at the bottom of the article, all its times are ERT (Earth Received Time), 44 minutes after SCET (SpaceCraft Event Time). With your viewpoint following the spacecraft, Celestia should show these events to be happening at the times listed in the last column. Actually, since Celestia does not implement light travel time, the events also will happen at SCET when observed using a telescopic viewpoint at the Earth's position.
Post-encounter note: Galileo entered safe mode about 16 minutes after its closest approach to Amalthea, cutting short data acquisition. For details, see the NASA press releases at http://www.jpl.nasa.gov/releases/2002/release_2002_205.cfm. and http://www.jpl.nasa.gov/releases/2002/release_2002_213.cfm.
![]() galileo-021105.avi (1.5MB, Divx encoded) |
This is a demonstration of a new feature in Celestia v1.3:
multiple panes in a single window. This example has four viewpanes
with their viewpoints set to observe several of the events
described in the table above, as seen by Galileo. Time advances at the
same rate in all of the viewpanes, so your attention has to move from
one to another as the events unfold. In order, they happen
counter-clockwise from the upper right:
Upper right: Io flyby, Upper left: Amalthea flyby,
The JPEG snapshot was recorded after Io's flyby and before Amalthea's, although the active viewpane is the one observing the Solar eclipse. The accompanying Divx recording shows all of the events in order, but was made at a time rate of 1000x to keep it small. The eclipses of the Sun and Earth are particularly quick. |
The Neptune, Triton and Voyager heliocentric xyz trajectories below each conatain 400 samples from 09:00 UTC August 23rd through 09:00 August 27th, 1989. Celestia currently (as of v1.2.5) uses single precision for the xyz positions. This introduces noticable errors at the distance of Neptune.
Triton's position using heliocentric xyz coordinates. Obtained from Horizons (Not needed for Celestia v1.2.5)
Object | Orbit Files | Comments |
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Nozomi Mars probe (aka "Planet B") | . |
Japanese Mars Probe
due to arrive at Mars in January, 2004. See http://www.planet-b.isas.ac.jp/index-e.html
Be sure to get nozomi.zip from
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. | nozomi.ssc (1KB, 3May03) | Elliptical orbital elements for May 3, 2003. just before the final Earth gravity assist. |
. | nozomi-em.ssc (1KB, 3May03) | Elliptical orbital elements for September 1, 2003, somewhere between Earth and Mars. |
See also: