PDS_VERSION_ID = PDS3
RECORD_TYPE = STREAM
LABEL_REVISION_NOTE = "
2003-02-20 CASSINI: conner Revision 1;
2003-03-06 PDS/RS: simpson Revision 2;
2003-03-18 CASSINI: conner Revision 3;
2003-03-20 PDS/RS: simpson Revision 4;
2003-03-21 CASSINI conner Revision 5;
2003-03-24 CASSINI conner Revision 6;
2003-04-21 CASSINI conner Revision 7;
2003-06-23 CASSINI conner Revision 8
2003-07-01 PDS/CN: S.L. Adams, formatted for ingestion from WORD
to ASCII of 'Revision 8' supplied
by Diane Conner.
2003-07-14 CASSINI conner, corrected spelling errors.
2003-09-22 CASSINI conner, added Solar System target.
2003-10-03 CASSINI conner, removed extra spaces at beg of line.
2003-10-16 CASSINI conner, changed to SOLAR_SYSTEM.
2004-03-08 CASSINI conner, replaced bad ref to 699-004."
OBJECT = MISSION
MISSION_NAME = "CASSINI-HUYGENS"
OBJECT = MISSION_INFORMATION
MISSION_START_DATE = 1997-10-15
MISSION_STOP_DATE = NULL
MISSION_ALIAS_NAME = { "CASSINI", "HUYGENS" }
MISSION_DESC = "
The majority of the text in this file was extracted from the Cassini
Mission Plan Document, D. Seal, 2003. [JPLD-5564]
The Cassini spacecraft, including the Huygens Probe, was launched on 15
October 1997 using a Titan IV/B launch vehicle with Solid Rocket Motor
Upgrade (SRMU) strap-ons and a Centaur upper stage. The spacecraft used a
6.7-year Venus-Venus-Earth-Jupiter Gravity Assist (VVEJGA) trajectory to
Saturn, during which cruise observations were conducted to check out,
calibrate, and maintain the instruments as well as to perform limited
science. After Saturn Orbit Insertion (SOI) (1 July 2004), the Huygens
Probe separated and, on the third encounter with Titan, entered the
satellite's atmosphere to make in situ measurements during an approximately
150 minute descent (14 January 2005). The Orbiter continued a tour of the
Saturn system until mid-2008 collecting data on the planet and its
satellites, rings, and environment.
The Cassini Orbiter (CO) was a three-axis stabilized spacecraft equipped
with one high gain antenna (HGA) and two low gain antennas (LGAs), three
Radioisotope Thermoelectric Generators (RTGs) for power, main engines,
attitude thrusters, and reaction wheels. It carried twelve orbiter
instruments designed to carry out 27 diverse science investigations. The
Huygens Probe (HP) was equipped with six instruments designed to study the
atmosphere and surface of Titan. It entered the upper atmosphere protected
by a heat shield, then deployed parachutes to descend slowly to the surface
from an altitude of about 200 km. The instruments, with acronym and
Principal Investigator (PI) or Team Leader (TL), are summarized below:
Instrument Acronym PI/TL
----------------------------------------------- ------------
Orbiter:
Cassini Plasma Spectrometer CAPS Young
Cosmic Dust Analyzer CDA Srama
Composite Infrared Spectrometer CIRS Flasar
Ion and Neutral Mass Spectrometer INMS Waite
Imaging Science Subsystem ISS Porco
Magnetometer MAG Dougherty
Magnetospheric Imaging Instrument MIMI Krimigis
Cassini Radar RADAR Elachi
Radio and Plasma Wave Science RPWS Gurnett
Radio Science Subsystem RSS Kliore
Ultraviolet Imaging Spectrograph UVIS Esposito
Visible and Infrared Mapping Spectrometer VIMS Brown
Probe:
Aerosol Collector and Pyrolyser ACP Israel
Descent Imager Spectral Radiometer DISR Tomasko
Doppler Wind Experiment DWE Bird
Gas Chromatograph Mass Spectrometer GCMS Niemann
Huygens Atmospheric Structure Instrument HASI Fulchignoni
Surface Science Package SSP Zarnecki
Mission Phases
==============
LAUNCH 1997-10-15 to 1997-10-17
1997-288 to 1997-290
------
Cassini successfully lifted-off from the Cape Canaveral Air Station complex
40 on 15 October 1997 at 08:55 UTC. The solid rocket motors burned from
liftoff to separation at 2 min 23 sec at an altitude of 68,300 m. Stage 1
ignition began at 2 min 11 sec at an altitude of 58,500 m, and Stage 2
ignition (and Stage 1 separation) occurred at 5 min 23 sec after liftoff at
167,300 m. During the first three minutes and 27 seconds of flight, the
payload fairing shrouded the spacecraft, protecting it from direct solar
illumination.
The Centaur upper stage separated from the launch vehicle at 9 min 13 sec
at 206,700 m. The first Centaur burn began at 9 min 13 sec and lasted
approximately two minutes. This burn placed the Cassini spacecraft into an
elliptical, 170 km by 445 km parking orbit with an inclination of about 30
degrees. After 17 minutes in the parking orbit, the Centaur fired again and
launched Cassini toward Venus en route to Saturn. The injection C3 was 16.6
km^2/s^2.
Immediately after separation from the Centaur (date?), the spacecraft's
Attitude and Articulation Control Subsystem (AACS) pointed the HGA toward
the Sun to achieve a thermally safe attitude in which the HGA served as an
umbrella for the remainder of the spacecraft. X-band uplink and downlink
was established through the LGAs, the Radio and Plasma Wave Science (RPWS)
Langmuir Probe was deployed, instrument replacement heaters and main engine
oxidizer valve heaters were turned on, and the Stellar Reference Unit
(SRU), Imaging Science Subsystem (ISS), and Visible and Infrared Mapping
Spectrometer (VIMS) decontaminations were started.
TCM 1 1997-10-18 to 1997-11-14
1997-291 to 1997-318
-----
The Trajectory Correction Maneuver 1 (TCM 1) phase comprised four one-week
sequences. During most of the TCM 1 phase, the spacecraft was in a
relatively quiescent state with the HGA pointed toward the Sun. Telemetry
downlinked by the spacecraft was utilized to make an initial
characterization of the spacecraft and to assess whether its various
subsystems survived the launch. Deployment, decontamination, tank heating,
and AACS checkout activities were started.
Before the maneuver itself, the fuel and oxidizer tanks were heated in
order to avoid an irreversible overpressure in the propellant lines. If
the tanks fully pressurized before the spacecraft passed through the peak
temperature regime, then (when the spacecraft did enter the maximum thermal
environment) the tank pressure would climb without there being a way to
bring it back down, possibly causing an overpressure.
TCM 1 was an Earth injection clean-up maneuver placed at 25 days after
launch. TCM 1 was executed using the main engine with a delta-V magnitude
of 2.8 m/s. The burn sequence included holding the spacecraft off-Sun after
burn completion to allow the spacecraft heating to be characterized in a
relatively benign environment.
INTERPLANETARY CRUISE 1997-11-14 to 1999-11-07
1997-318 to 1999-311
---------------------
The Interplanetary Cruise Phase extended from 14 November 1997 to 7
November 1999. It consisted of three subphases: Venus 1 Cruise,
Instrument Checkout 1, and Venus 2 - Earth Cruise. During most of this
phase, Cassini's proximity to the Sun constrained the spacecraft to remain
Sun-pointed, and communications were conducted using the Low Gain Antennas.
The downlink capability of the LGAs at large spacecraft-Earth ranges was
very limited. Between 30 and 150 days after launch, for example, the
downlink data rate decreased from 948 to 20 bps.
Beginning on 28 December 1998, the spacecraft approached opposition and the
HGA could be pointed towards Earth for a period of 25 days while the Probe
equipment temperature remained within the required range. This provided a
high data rate window during which checkout activities could be
accomplished.
VENUS 1 CRUISE 1997-11-14 to 1998-09-13
1997-318 to 1998-256
--------------
The Venus 1 Cruise subphase started on 14 November 1997 and continued
through 13 September 1998. The subphase encompassed sequences C5 through C9
and included two TCMs, one planetary swingby, and three switches between
LGA1 and LGA2. Most of the period was dedicated to engineering and
instrument maintenance activities.
VENUS 1 ENCOUNTER 1998-04-26
1998-116
The first Venus encounter occurred on 26 April 1998. The spacecraft
approached Venus from a sunward direction, and closest approach occurred
just after the spacecraft entered the Sun's shadow for a period of about 15
minutes. At closest approach, the altitude was 284 km, with a velocity
relative to Venus of 11.8 km/s. The spacecraft was occulted from Earth for
about 2 hours. The Earth occultation zone started about 15 minutes after
the spacecraft left the Sun occultation zone. Accuracy for the Venus flyby
was assured by using two TCMs (Trajectory Correction Maneuvers), 60 and 20
days before closest approach, and a clean-up maneuver 20 days after the
flyby.
INSTRUMENT CHECKOUT 1 1998-09-14 to 1999-03-14
1998-257 to 1999-073
---------------------
The Instrument Checkout 1 subphase (ICO-1) started on 14 September 1998,
continued through 14 March 1999, and consisted of sequences C10-C13. This
subphase was characterized by the opposition that occurred on 9 January
1999, which allowed use of the HGA for downlink since the Earth and Sun
were nearly aligned as seen from Cassini.
All instruments scheduled checkout activities within the 25 day period
centered on opposition. This was the first opportunity since launch to
exercise and check the status of most instruments outside of routine
maintenance. The 'Quiet Test', for example, allowed each instrument to
monitor other instruments as they turned on and off and provided valuable
insight into how to integrate science observations during the Saturn tour.
During instrument checkout activities, the spacecraft autonomously went
into a safe state. Accumulating star position errors from the slow turn
required to keep the Sun on the -x-axis triggered AACS fault protection.
Most of the instrument checkout activities were rescheduled after a 10 day
safing period. Those that were not completed were rescheduled for the ICO-2
subphase during Outer Cruise.
VENUS 2 - EARTH CRUISE 1999-03-15 to 1999-11-07
1999-074 to 1999-311
----------------------
The Venus 2 - Earth Cruise subphase started on 15 March 1999, 45 days prior
to the second Venus flyby, and continued through 7 November 1999, which was
82 days after the Earth flyby. The subphase encompassed sequences C13
through C16, and included seven scheduled TCMs, two planetary swingbys, and
25 science activities in addition to normal engineering activities. Science
activities included maintenance, calibration, checkout, and science
observations using all of the Cassini instruments except INMS and CIRS.
VENUS 2 ENCOUNTER 1999-06-24
1999-175
TCM-7 was executed 37 days before the Venus 2 Encounter. TCM-8 was
scheduled 21 days prior to Venus 2, but it was canceled. DSN (Deep Space
Network) coverage increased from one to three passes per day in support of
the flyby.
EARTH ENCOUNTER 1999-08-18
1999-230
The Earth flyby occurred 55 days after the Venus 2 flyby. The spacecraft
approached the Earth from approximately the direction of the Sun. Closest
approach occurred right after the spacecraft entered the Sun occultation
zone. The occultation lasted approximately 30 minutes. The altitude at
closest approach was 1175 km, with an Earth-relative velocity of 19.0 km/s.
Trajectory correction maneuvers took place 43, 30, 15 and 6.5 days before
closest approach, and a clean-up maneuver was executed 13 days after the
flyby. Continuous DSN coverage began at the Venus 2 flyby and continued
through the Earth flyby. A week after the Earth Encounter, DSN coverage
dropped to one pass every two days.
Five instruments conducted observations as Cassini passed through the
Earth's magnetotail.
OUTER CRUISE 1999-11-08 to 2002-07-07
1999-312 to 2002-188
------------
The Outer Cruise Phase consisted of four subphases: HGA Transition,
Instrument Checkout 2, Jupiter Cruise, and Quiet Cruise. The Outer Cruise
phase extended from 8 November 1999 (when the spacecraft reached a Sun
range of 2.7 AU) to 7 July 2002 (about two years before Saturn Orbit
Insertion). At 2.7 AU (1 February 2000), the HGA began continuous Earth-
pointing. The one planetary encounter in this phase was the flyby of
Jupiter in December 2000. Science at Jupiter was an opportunity to test
Saturn observation strategies with HGA data rates.
HIGH GAIN ANTENNA TRANSITION 1999-11-08 to 2000-05-06
1999-312 to 2000-127
----------------------------
This subphase included sequences C17 to C19, operation of ISS and VIMS
decontamination heaters, CDA dust calibrations, and Magnetosphere and
Plasma Science (MAPS) observations after the HGA was pointed toward Earth.
During the initial part of the subphase (C17 and part of C18),
telecommunications were via LGA1, and the spacecraft was at the farthest
distance from Earth before transitioning to the HGA for regular use.
Therefore, data rates were very low and activities were kept to a minimum.
C17 included standard maintenance and one Periodic Engineering Maintenance
(PEM) activity. Activities during the LGA1 portion of C18 included a
Periodic Instrument Maintenance (PIM); observations by ISS, VIMS, and UVIS
of the asteroid Masursky near closest approach (1,634,000 km); and ISS dark
frame calibration images directly following the Masursky observations.
The HGA was turned toward Earth for regular use on 1 February 2000, during
C18. Several activities took place during the rest of C18, using the
greater telemetry capabilities available with the HGA: playback of the
Masursky data and ISS dark frames, a Probe checkout, a Huygens Probe S-band
Relay to Cassini Test, a Telemetry-Ranging Interference Test, MAG
calibrations, and a PEM. Regular MAPS observations by CAPS, CDA, MAG, MIMI,
and RPWS began within a few days after transitioning to the HGA.
The first 6 weeks of C19 were used for a checkout of new Flight Software.
The AACS version A7 software was uploaded near the beginning of this
period, and the first 2 weeks were devoted to AACS tests. The next 4 weeks
were originally scheduled for CDS tests of version V7.0. However, these
tests were delayed to late July and August of 2000 to allow time for
additional regression testing. During the AACS checkout period, MAPS
activity ceased. Several activities took place during the last 3 weeks of
C19: resumption of MAPS observations, three RSS activities (HGA pattern
calibration, HGA boresight calibration, and USO characterization), CIRS
Cooler Cover release, and a PIM.
A few days before the end of C19, the command loss timer setting was
increased slightly, to account for the 10-day period at the beginning of
C20 during which superior conjunction made commanding problematic.
INSTRUMENT CHECKOUT 2 2000-05-06 to 2000-11-05
2000-127 to 2000-310
---------------------
The second instrument checkout subphase (ICO-2) was scheduled from 6 May
2000 to 5 November of 2000, after the Spacecraft Office had completed its
engineering checkout activities. ICO-2 included instrument checkout that
required reaction wheel stability and any instrument checkouts that were
not successfully completed during ICO-1. But the CDS Flight Software V7
uplink and checkout, which was delayed from March, was rescheduled to late
July through early September 2000, causing many ICO-2 activities to be
compressed into a shorter and more intense period. Some activities were
postponed until after the Jupiter observations were completed in 2001.
The subphase began with a superior conjunction which precluded early
science or engineering activities. MAPS instruments remained on; but data
return was not attempted during conjunction. Two TCMs were scheduled for
Jupiter targeting, in June and September.
Engineering activities included the continuous use of reaction wheels and,
beginning on 1 October 2000, dual Solid State Recorders (SSRs). There were
no scheduled instrument PIMs during ICO-2 since all instruments had other
activities that accomplished this function. Other engineering activities
included two Reaction Wheel Assembly (RWA) friction tests, two PEMs, and an
SRU calibration.
Science activities began with the MAPS instruments continuing from C19. New
flight software was loaded for eight instruments in late May, and a CDA
software update was done in September. New Quiet Tests, while operating on
reaction wheels, were done in July for most instruments. RSS Quiet Tests
were done in September, and RADAR related tests were done in late June. A
Probe checkout occurred in late July.
Spacecraft turns were done for RADAR observations of the Sun and Jupiter in
June and again in September. The star Alpha Piscis Austrinus (Fomalhaut)
was also observed in September by VIMS with ISS and UVIS doing ride-along
science. No other science turns were scheduled until October. On 1 October,
science began using a repeating 5-day template to gather Jupiter science.
This involved 11 turns in a 5 day period, including two downlinks. The
turns in the 5-day template involved 4 orientations:
Orbiter Remote Science (ORS) boresights to Jupiter,
Z axis parallel to ecliptic
HGA to Sun, rolling about Z axis
Probe to Sun, rotating about X axis
HGA to Earth, Probe offset from Sun for CDA, not
rotating, downlink orientation
JUPITER CRUISE 2000-11-05 to 2001-04-30
2000-310 to 2001-120
--------------
The Jupiter Cruise subphase extended from 6 November 2000 to 29 April 2001
and included sequences C23 to C25. However Jupiter remote sensing
observations actually began on 1 October 2000, in C22.
JUPITER ENCOUNTER 2000-12-30
2000-365
The Jupiter flyby occurred on 30 December 2000 at an altitude of 9.7
million km. This gravity assist rotated the trajectory 12 deg and increased
the heliocentric velocity by 2 km/s. The Jupiter relative speed at closest
approach was 11.6 km/s. At closest approach, Jupiter filled the Narrow
Angle Camera (NAC) field of view. Extensive Jupiter science was performed
which required additional DSN support: up to two passes every five days,
and a maximum of one pass every 30 hours in the 10 days on either side of
closest approach. Science at Jupiter was an opportunity to test how to
build and execute viable Saturn sequences.
A problem with the RWAs occurred on 16 December 2000. Increased friction on
one of the wheels caused the spacecraft to switch autonomously to the
Reaction Control Subsystem (RCS) for attitude control. With the switch to
RCS, hydrazine usage increased. Two of four joint CAPS-Hubble Space
Telescope observations, a Jupiter North-South map, the Himalia 'flyby', and
a UVIS torus observation were all executed on RCS before the sequence was
terminated on 19 December 2000. MAPS data continued to be recorded at a
reduced rate. All other planned science activities were suspended. After
tests, RWA operation was resumed for attitude control on 22 December, with
the wheels biased away from low RPM regions. The sequence was restarted on
29 December.
QUIET CRUISE 2001-04-30 to 2002-07-08
2001-120 to 2002-189
------------
Quiet Cruise was a 14 month subphase that started at the end of Jupiter
Cruise and ended two years before SOI. During this subphase, routine
maintenance, engineering, and navigation functions were carried out. One
Gravitational Wave Experiment (GWE) was conducted in December 2001, and one
Solar Conjunction Experiment (SCE) was conducted in June 2002.
SCIENCE CRUISE 2002-07-08 to 2004-06-10
2002-189 to 2004-162
--------------
SPACE SCIENCE 2002-07-08 to 2004-01-11
2002-189 to 2004-011
The Space Science subphase began on 8 July 2002 and ran through 11 January
2004. TCMs 18 and 19, two GWEs (December 2002 and December 2003) and one
SCE (June-July 2003) were conducted.
APPROACH SCIENCE 2004-01-12 to 2004-06-10
2004-012 to 2004-162
The Approach Science subphase began six months before SOI and ended three
weeks before SOI, when the spacecraft was approaching Saturn at a rate of 5
kilometers per second. Most of the activities during the Approach Science
subphase were Saturn science observations and preparation for the Phoebe
flyby, SOI, and Tour operations.
The reaction wheels were turned on at the beginning of the subphase to
provide a more stable viewing platform. By this point, the imaging
instruments had begun atmospheric imaging, and making long-term atmospheric
movies. CIRS began long integrations of Saturn's disk. At SOI - 4 months,
Saturn filled one third of the NAC field of view and one half of the CIRS
Far Infrared (FIR) field of view.
The Saturn approach was made toward the morning terminator at a phase angle
of about 75 degrees; VIMS gathered data on the temperature difference
across the terminator. UVIS scans of the Saturn System began 3-4 months
before SOI. Fields, particles, and waves instruments collected solar wind
information and recorded Saturn emissions as the spacecraft neared the
planet. Science data gathered during this period was stored on the SSR and
transmitted back to Earth. Daily DSN tracking coverage began 90 days before
SOI.
The Phoebe approach TCM took place on 27 May 2004, 15 days before Phoebe
closest approach.
TOUR PRE-HUYGENS 2004-06-11 to 2004-12-24
2004-163 to 2004-359
----------------
The Tour Pre-Huygens Phase extended from the Phoebe Encounter through
Saturn Orbit Insertion to separation of the Huygens Probe from the Cassini
Orbiter.
PHOEBE ENCOUNTER 2004-06-11
2004-163
The flyby of Phoebe occurred on 11 June 2004, 19 days before SOI. At
closest approach (19:33 UTC) the spacecraft was 2000 km above the surface.
SATURN ORBIT INSERTION 2004-07-01
2004-183
During Saturn Orbit Insertion (SOI) on 1 July 2004, the spacecraft made its
closest approach to the planet's surface during the entire mission at an
altitude of only 0.3 Saturn radii (18,000 km). Due to this unique
opportunity, the approximately 95-minute SOI burn (633 m/s total delta-V),
required to place Cassini in orbit around Saturn, was executed earlier than
its optimal point centered around periapsis, and instead ended near
periapsis, allowing science observations immediately after burn completion.
The SOI maneuver placed the spacecraft in an initial orbit with a periapsis
radius of 1.3 Rs, a period of 148 days, and an inclination of 16.8 degrees.
After the burn, the spacecraft was turned to allow the ORS instruments to
view the Saturn inner rings that were not in shadow. After periapsis, the
trajectory just grazed the occultation zones behind the planet with the
Earth and Sun being occulted by Saturn. After communication with Earth was
re-established, the spacecraft remained on Earth pointed for nine hours to
play back engineering and science data and to give ground personnel time to
evaluate the spacecraft status.
After SOI a pair of cleanup maneuvers was used to correct for errors in the
SOI burn. The first was immediately before superior conjunction, at SOI + 3
days, and the second was after conjunction at SOI + 16 days.
Probe checkouts were scheduled at SOI + 14 days, Probe Release Maneuver
(PRM) + 4 days, and ten days before separation.
The partial orbit between SOI and the first apoapsis was designated orbit
0. The next three orbits were designated a, b, and c.
TITAN A ENCOUNTER 2004-10-26
2004-300
TITAN B ENCOUNTER 2004-12-13
2004-348
HUYGENS DESCENT 2004-12-24 to 2005-01-14
2004-359 to 2005-014
---------------
HUYGENS PROBE SEPARATION 2004-12-24
2004-359
The probe was released from the Orbiter on 24 December 2004, 11 days after
the second Titan flyby (orbit b). Two days after the Probe was released,
the Orbiter executed a deflection maneuver to place itself on the proper
trajectory for the third encounter.
TITAN C HUYGENS 2005-01-14
2005-014
During the third flyby (orbit c), on 14 January 2005, the Huygens Probe
transmitted data to the orbiter for approximately 150 minutes during its
descent through the atmosphere to the surface.
Because the Orbiter was looking at Titan through most of the corresponding
Goldstone tracking pass, DSN support on this day was primarily through the
70-meter antennas at the Canberra and Madrid tracking complexes. While
approaching Titan, the Orbiter made its last downlink transmission (to the
Madrid station, DSS 63) before switching to Probe relay mode. The Orbiter
then turned nearly 180 degrees to point its HGA at the predicted Probe
impact point, and the Probe Support Avionics (PSA) were configured to
receive data from the Probe. Some Orbiter instruments were put into a low
power state to provide additional power for the PSA. The data from the
Probe were transmitted at S band in two separate data streams, and both
were recorded on each SSR. Following completion of the predicted descent
(maximum 150 minutes), the Orbiter listened for Probe signals for an
additional 30 minutes, in case they continued after landing.
When data collection from the Probe was completed, those data were write
protected on each SSR. The spacecraft then turned to view Titan with
optical remote sensing instruments until about one hour after closest
approach for a total observing window of TBD.
The Orbiter then turned the HGA towards Earth and began transmitting the
recorded Probe data to the Canberra 70-m antenna. The complete, four-fold
redundant set of Probe data was transmitted twice, and its receipt
verified, before the write protection on that portion of the SSR was lifted
by ground command. A second playback, including all of the Probe data and
the Orbiter instrument observations, was returned over the subsequent
Madrid 70-meter tracking pass, which was longer and at higher elevation
angles.
TOUR 2005-01-14 to 2008-06-30
2005-014 to 2008-182
----
The Tour Phase of the mission began at completion of the Huygens Probe and
Orbiter-support playback and ended on 30 June 2008. It included dozens of
satellite encounters and extended observations of Saturn, its rings, and
its environment of particles and fields.
TOUR SEQUENCE BOUNDARIES
The table below shows spacecraft background sequences, orbit revolution,
start epoch (including day-of-year in a separate column), and the length of
the sequence. For completeness, all 'S' sequences are listed even though
the first seven covered times before the Tour phase. Each orbit about
Saturn was assigned a revolution identifier starting with a, b, and c, and
then numerically ascending from 3 to 74; these were not synchronous with
sequences, some of which covered only partial orbits. Full orbits began
and ended at apoapsis; the partial orbit from SOI to the first apoapsis was
orbit 0.
Sequence Rev Epoch (SCET) DOY Duration
In days
-------- --- ----------------- --- --------
S1 - 2004-May-15 00:00 136 35
S2 0 2004-Jun-19 01:38 171 42
S3 0 2004-Jul-30 23:05 212 43
S4 a 2004-Sep-11 19:10 255 35
S5 a 2004-Oct-16 18:40 290 28
S6 a 2004-Nov-13 16:59 318 33
S7 b 2004-Dec-16 15:03 351 37
S8 c 2005-Jan-22 10:38 022 36
S9 3 2005-Feb-27 00:36 058 41
S10 6 2005-Apr-09 05:15 099 35
S11 8 2005-May-14 02:50 134 35
S12 10 2005-Jun-18 01:34 169 42
S13 12 2005-Jul-29 22:36 210 32
S14 14 2005-Aug-30 21:53 242 39
S15 16 2005-Oct-08 15:57 281 35
S16 17 2005-Nov-12 17:01 316 35
S17 19 2005-Dec-17 14:21 351 42
S18 20 2006-Jan-28 11:23 028 42
S19 22 2006-Mar-11 00:35 070 42
S20 23 2006-Apr-22 05:15 112 42
S21 24 2006-Jun-03 02:39 154 42
S22 26 2006-Jul-15 00:06 196 35
S23 27 2006-Aug-18 22:06 230 39
S24 29 2006-Sep-26 19:53 269 26
S25 31 2006-Oct-22 18:26 295 33
S26 33 2006-Nov-24 16:30 328 42
S27 36 2007-Jan-05 13:50 005 43
S28 39 2007-Feb-17 10:52 048 40
S29 41 2007-Mar-29 08:04 088 37
S30 44 2007-May-04 22:00 124 37
S31 46 2007-Jun-11 03:10 162 33
S32 48 2007-Jul-14 01:06 195 29
S33 49 2007-Aug-11 23:20 223 42
S34 50 2007-Sep-22 20:51 265 40
S35 51 2007-Nov-01 18:40 305 42
S36 54 2007-Dec-13 16:15 347 39
S37 56 2008-Jan-21 13:35 021 26
S38 59 2008-Feb-16 11:51 047 36
S39 62 2008-Mar-23 01:50 083 27
S40 65 2008-Apr-19 07:18 110 42
S41 70 2008-May-31 04:27 152 35
SATELLITE ENCOUNTER SUMMARY
This table summarizes the Cassini Orbiter satellite encounters; for
completeness, all recognized encounters are included even though the first
eight preceded the Tour phase. Rev identifies the orbit revolution as
defined above. The three character ID for the encounter is in the second
column; an appended asterisk (*) denotes a non-targeted encounter. The
target, date and time, and day-of-year are in the next three columns.
Altitude above the surface at closest approach, sense of the encounter
(whether on the inbound or outbound leg of an orbit), relative velocity at
closest approach, and phase angle at closest approach round out the
columns.
Rev Name Satellite Epoch (SCET) DOY Alt in/ Speed Phase
km out km/s deg
---- ----- --------- ---------------- --- --- --- ----- ----
0 0PH Phoebe 2004-Jun-11 19:33 163 1997 in 6.4 25
0 0MI* Mimas 2004-Jul-01 00:30 183 76424 in 22.3 80
0 0TI* Titan 2004-Jul-02 09:30 184 338958 out 8.3 67
a aTI Titan 2004-Oct-26 15:30 300 1200 in 6.1 91
b bTI Titan 2004-Dec-13 11:37 348 2358 in 6 98
b bDI* Dione 2004-Dec-15 02:11 350 81592 in 5.3 93
c cIA* Iapetus 2005-Jan-01 01:28 001 64907 in 2.1 106
c cTI Titan 2005-Jan-14 11:04 014 60000 in 5.4 93
3 3TI Titan 2005-Feb-15 06:54 046 950 in 6 102
3 3EN* Enceladus 2005-Feb-17 03:24 048 1179 out 6.6 98
4 4EN Enceladus 2005-Mar-09 09:06 068 499 in 6.6 43
4 4TE* Tethys 2005-Mar-09 11:42 068 82975 out 6.9 64
5 5EN* Enceladus 2005-Mar-29 20:20 088 63785 in 10.1 134
5 5TI Titan 2005-Mar-31 19:55 090 2523 out 5.9 65
6 6MI* Mimas 2005-Apr-15 01:20 105 77233 out 13.6 94
6 6TI Titan 2005-Apr-16 19:05 106 950 out 6.1 127
7 7TE* Tethys 2005-May-02 21:04 122 64990 in 10 118
7 7TI* Titan 2005-May-04 05:10 124 860004 out 10.2 153
8 8EN* Enceladus 2005-May-21 07:19 141 92997 out 8.1 81
9 9TI* Titan 2005-Jun-06 18:50 157 425973 in 5.8 82
10 10TI* Titan 2005-Jun-22 12:27 173 920423 in 3.7 65
11 11EN Enceladus 2005-Jul-14 19:57 195 1000 in 8.1 43
12 12MI* Mimas 2005-Aug-02 03:52 214 45112 in 6.5 83
12 12TI* Titan 2005-Aug-06 12:33 218 841452 out 3.8 62
13 13TI Titan 2005-Aug-22 08:39 234 4015 out 5.8 42
14 14TI Titan 2005-Sep-07 07:50 250 950 out 6.1 84
15 15TE* Tethys 2005-Sep-24 01:29 267 33295 out 7.7 76
15 15TI* Titan 2005-Sep-24 22:01 267 910272 out 10.7 148
15 15HY Hyperion 2005-Sep-26 01:41 269 990 out 5.6 45
16 16TI* Titan 2005-Oct-10 22:20 283 777198 in 9.7 65
16 16DI Dione 2005-Oct-11 17:58 284 500 in 9 66
16 16EN* Enceladus 2005-Oct-12 03:29 285 42635 out 6.6 75
17 17TI Titan 2005-Oct-28 03:58 301 1446 in 5.9 105
18 18RH Rhea 2005-Nov-26 22:35 330 500 in 7.3 87
19 19EN* Enceladus 2005-Dec-24 20:23 358 97169 in 6.9 133
19 19TI Titan 2005-Dec-26 18:54 360 10429 out 5.6 67
20 20TI Titan 2006-Jan-15 11:36 015 2042 in 5.8 121
21 21TI Titan 2006-Feb-27 08:20 058 1812 out 5.9 93
22 22TI Titan 2006-Mar-18 23:58 077 1947 in 5.8 148
22 22RH* Rhea 2006-Mar-21 07:01 080 85935 out 5.3 136
23 23TI Titan 2006-Apr-30 20:53 120 1853 out 5.8 121
24 24TI Titan 2006-May-20 12:13 140 1879 in 5.8 163
25 25TI Titan 2006-Jul-02 09:12 183 1911 out 5.8 148
26 26TI Titan 2006-Jul-22 00:25 203 950 in 6 105
27 27TI* Titan 2006-Aug-18 17:48 230 339190 out 4.8 121
28 28TI Titan 2006-Sep-07 20:12 250 950 in 6 45
28 28EN* Enceladus 2006-Sep-09 20:00 252 39842 out 10.3 116
29 29TI Titan 2006-Sep-23 18:52 266 950 in 6 90
30 30TI Titan 2006-Oct-09 17:23 282 950 in 6 81
31 31TI Titan 2006-Oct-25 15:51 298 950 in 6 25
32 32EN* Enceladus 2006-Nov-09 01:48 313 94410 out 14.1 27
33 33DI* Dione 2006-Nov-21 02:32 325 72293 out 12.3 144
33 33TI* Titan 2006-Nov-25 13:57 329 930525 out 4.5 114
35 35TI Titan 2006-Dec-12 11:35 346 950 in 6 124
36 36TI Titan 2006-Dec-28 10:00 362 1500 in 5.9 62
37 37TI Titan 2007-Jan-13 08:34 013 950 in 6 53
38 38TI Titan 2007-Jan-29 07:12 029 2776 in 5.8 73
39 39TI Titan 2007-Feb-22 03:10 053 953 out 6.3 161
40 40TI Titan 2007-Mar-10 01:47 069 956 out 6.3 149
41 41TI Titan 2007-Mar-26 00:21 085 953 out 6.3 144
42 42TI Titan 2007-Apr-10 22:57 100 951 out 6.3 137
43 43TI Titan 2007-Apr-26 21:32 116 951 out 6.3 130
44 44TI Titan 2007-May-12 20:08 132 950 out 6.3 121
45 45TE* Tethys 2007-May-26 20:57 146 97131 in 11.7 75
45 45TI Titan 2007-May-28 18:51 148 2425 out 6.1 114
46 46TI Titan 2007-Jun-13 17:46 164 950 out 6.3 107
47 47TE* Tethys 2007-Jun-27 19:53 178 16166 in 10.1 90
47 47MI* Mimas 2007-Jun-27 22:56 178 89730 in 16.2 110
47 47EN* Enceladus 2007-Jun-28 01:15 179 90769 out 9.4 55
47 47TI Titan 2007-Jun-29 17:05 180 1942 out 6.2 96
48 48TI Titan 2007-Jul-19 00:39 200 1302 in 6.2 34
49 49TE* Tethys 2007-Aug-29 11:21 241 48324 in 4.7 104
49 49RH* Rhea 2007-Aug-30 01:26 242 5098 out 6.7 46
49 49TI Titan 2007-Aug-31 06:34 243 3227 out 6.1 87
49 49IA Iapetus 2007-Sep-10 12:33 253 1000 out 2.4 65
50 50DI* Dione 2007-Sep-30 06:27 273 56523 in 5.6 47
50 50EN* Enceladus 2007-Sep-30 10:53 273 88174 in 6.1 99
50 50TI Titan 2007-Oct-02 04:48 275 950 out 6.3 67
51 51TI* Titan 2007-Oct-22 00:47 295 455697 in 4.1 29
52 52RH* Rhea 2007-Nov-16 19:52 320 78360 in 9.1 148
52 52TI Titan 2007-Nov-19 00:52 323 950 out 6.3 51
53 53MI* Mimas 2007-Dec-03 05:28 337 79272 in 14.8 138
53 53TI Titan 2007-Dec-05 00:06 339 1300 out 6.3 70
54 54TI Titan 2007-Dec-20 22:56 354 953 out 6.3 61
55 55TI Titan 2008-Jan-05 21:26 005 949 out 6.3 37
57 57TI* Titan 2008-Jan-22 21:06 022 860776 in 4.5 70
59 59TI Titan 2008-Feb-22 17:39 053 959 out 6.4 30
61 61TI* Titan 2008-Mar-10 19:15 070 922539 in 6.3 123
61 61EN Enceladus 2008-Mar-12 19:05 072 995 in 14.6 56
62 62TI Titan 2008-Mar-25 14:35 085 950 out 6.4 21
64 64MI* Mimas 2008-Apr-11 09:38 102 95428 in 16.9 137
66 66TI* Titan 2008-Apr-26 18:22 117 780589 in 5.5 94
67 67TI Titan 2008-May-12 10:09 133 950 out 6.4 35
69 69TI Titan 2008-May-28 08:33 149 1316 out 6.3 23
72 72TI* Titan 2008-Jun-13 04:17 165 372240 in 5.9 89
74 74EN* Enceladus 2008-Jun-30 08:07 182 99092 in 21.6 66
END OF PRIME MISSION 2008-06-30
2008-182
-------------------- "
MISSION_OBJECTIVES_SUMMARY = "
CASSINI-HUYGENS MISSION OBJECTIVES
==================================
The Cassini-Huygens mission will accomplish a variety of scientific
objectives en route to and at Saturn [JPLD-5564].
While en route to Saturn, Cassini performed three sets of Gravitational
Wave Experiments (GWEs), each scheduled near opposition and each lasting
approximately 40 days. During these observations, Cassini acted as a point
mass which would be perturbed by propagating gravitational waves resulting
from sudden destruction (or creation) of large masses in the general
direction of the spacecraft-to-Earth line.
While en route to Saturn, Cassini was also used in two Solar Conjunction
Experiments (SCEs), each lasting approximately 30 days. The objectives of
these observations was to test general relativity and to improve our
understanding of the solar corona.
The general scientific objectives of the Cassini mission at Saturn were to
investigate the physical, chemical, and temporal characteristics of Titan
and of Saturn, its atmosphere, rings, icy satellites, and magnetosphere.
These are listed more specifically below:
Saturn (Planet) Objectives.
--------------------------
a) Determine temperature field, cloud properties, and composition of the
atmosphere of Saturn.
b) Measure the global wind field, including wave and eddy components;
observe synoptic cloud features and processes.
c) Infer the internal structure and rotation of the deep atmosphere.
d) Study the diurnal variations and magnetic control of the ionosphere of
Saturn.
e) Provide observational constraints (gas composition, isotope ratios, heat
flux, etc.) on scenarios for the formation and the evolution of Saturn.
f) Investigate the sources and the morphology of Saturn lightning, Saturn
Electrostatic Discharges (SED), and whistlers.
Titan Objectives.
----------------
a) Determine abundance of atmospheric constituents (including any noble
gases), establish isotope ratios for abundant elements, constrain scenarios
of formation and evolution of Titan and its atmosphere.
b) Observe vertical and horizontal distributions of trace gases, search for
more complex organic molecules, investigate energy sources for atmospheric
chemistry, and model the photochemistry of the stratosphere, study
formation and composition of aerosols.
c) Measure winds and global temperatures; investigate cloud physics,
general circulation, and seasonal effects in Titan's atmosphere; search for
lightning discharges.
d) Determine the physical state, topography, and composition of the
surface; infer the internal structure of the satellite.
e) Investigate the upper atmosphere, its ionization, and its role as a
source of neutral and ionized material for magnetosphere of Saturn.
Ring Objectives.
---------------
a) Study configuration of the rings and dynamical processes (gravitational,
viscous, erosional, and electromagnetic) responsible for ring structure.
b) Map composition and size distribution of ring material.
c) Investigate interrelation of rings and satellites, including embedded
satellites.
d) Determine dust and meteoroid distribution in the vicinity of the rings.
e) Study interactions between the rings and Saturn's magnetosphere,
ionosphere, and atmosphere.
Icy Satellite Objectives.
------------------------
a) Determine the general characteristics and geological histories of the
satellites.
b) Define the mechanisms of crustal and surface modifications, both
external and internal.
c) Investigate the compositions and distributions of surface materials,
particularly dark, organic rich materials and low melting point condensed
volatiles.
d) Constrain models of the satellites' bulk compositions and internal
structures.
e) Investigate interactions with the magnetosphere and ring systems and
possible gas injections into the magnetosphere.
Magnetosphere Objectives
------------------------
a) Determine the configuration of the nearly axially symmetric magnetic
field and its relation to the modulation of Saturn Kilometric Radiation
(SKR).
b) Determine current systems, composition, sources, and sinks of
magnetosphere charged particles.
c) Investigate wave-particle interactions and dynamics of the dayside
magnetosphere and the magnetotail of Saturn and their interactions with the
solar wind, the satellites, and the rings.
d) Study the effect of Titan's interaction with the solar wind and
magnetospheric plasma.
e) Investigate interactions of Titan's atmosphere and exosphere with the
surrounding plasma. "
END_OBJECT = MISSION_INFORMATION
OBJECT = MISSION_HOST
INSTRUMENT_HOST_ID = "CO"
OBJECT = MISSION_TARGET
TARGET_NAME = "SATURN"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "TITAN"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "MASURSKY"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "FOMALHAUT"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "SPICA"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "EARTH"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "VENUS"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
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END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "MOON"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "JUPITER"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "CALLISTO"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "EUROPA"
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OBJECT = MISSION_TARGET
TARGET_NAME = "GANYMEDE"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "IO"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "S RINGS"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "ATLAS"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "CALYPSO"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "DIONE"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "ENCELADUS"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "EPIMETHEUS"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "HELENE"
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OBJECT = MISSION_TARGET
TARGET_NAME = "HYPERION"
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OBJECT = MISSION_TARGET
TARGET_NAME = "IAPETUS"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
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OBJECT = MISSION_TARGET
TARGET_NAME = "MIMAS"
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OBJECT = MISSION_TARGET
TARGET_NAME = "PAN"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "PANDORA"
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OBJECT = MISSION_TARGET
TARGET_NAME = "PHOEBE"
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OBJECT = MISSION_TARGET
TARGET_NAME = "PROMETHEUS"
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OBJECT = MISSION_TARGET
TARGET_NAME = "RHEA"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "TELESTO"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "TETHYS"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "SUN"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "IO PLASMA TORUS"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "SOLAR WIND"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "SOLAR_SYSTEM"
END_OBJECT = MISSION_TARGET
OBJECT = MISSION_TARGET
TARGET_NAME = "DUST"
END_OBJECT = MISSION_TARGET
END_OBJECT = MISSION_HOST
OBJECT = MISSION_HOST
INSTRUMENT_HOST_ID = "HP"
OBJECT = MISSION_TARGET
TARGET_NAME = "TITAN"
END_OBJECT = MISSION_TARGET
END_OBJECT = MISSION_HOST
OBJECT = MISSION_REFERENCE_INFORMATION
REFERENCE_KEY_ID = "JPLD-5564"
END_OBJECT = MISSION_REFERENCE_INFORMATION
END_OBJECT = MISSION
END
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