Cassini–Huygens timeline

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This page lists a chronology of events which have occurred or are expected to occur during the Cassini–Huygens mission to Saturn and Titan.

C-H imaged this on March 22, 2014 (MT2 and CL2 filters)
The initial gravitational-assist trajectory of Cassini–Huygens

1997[edit]

Launch occurred at 4:43 a.m. EDT (8:43 UTC) on October 15, 1997, from Space Launch Complex 40 at Cape Canaveral Air Force Station, Florida.

October 15 01:43 Pacific Daylight Time (PDT) – Cassini launched at 08:43 UTC inside Titan IVB/Centaur rocket.

1998[edit]

April 26 06:52 PDT – Gravity-assisted flyby of Venus at 284 km, receiving a boost in speed of about 7 kilometers per second.[1]

December 3 22:06 PDT – Cassini fired its main rocket engine for 90 minutes, setting the spacecraft on course for its second Venus flyby in 1999. The engine burn slowed the spacecraft by close to 450 meters per second (about 1,006 miles per hour) relative to the Sun. Cassini's speed went from 67,860 kilometers per hour (42,168 miles per hour) at the start of the maneuver to 66,240 kilometers per hour (41,161 miles per hour) at the end of the engine firing.[2]

1999[edit]

June 24 13:30 PDT – Gravity-assisted flyby of Venus at 623 km.[3]

Picture of Moon during flyby

August 18 03:28 UTC – Gravity-assisted flyby of Earth. An hour 20 minutes before closest approach, Cassini made the closest approach to the Moon at 377,000 km, and took a series of calibration images. The spacecraft flew past Earth at a distance of 1,171 kilometers (728 mi), passing most closely above the eastern South Pacific at 23°30′S 128°30′W / 23.5°S 128.5°W / -23.5; -128.5. Cassini received a 5.5-kilometer-per-second (about 12,000-mile-per-hour) boost in velocity.[4]

2000[edit]

January 23 – flyby of Asteroid 2685 Masursky around 10:00 UTC. Cassini took images[5] 5 to 7 hours before at 1.6 million km distance and estimated a diameter of 15 to 20 km.

Jupiter flyby picture

December 30 10:05 UTC – Gravity-assisted flyby of Jupiter. Cassini was at its closest point (9.7 million kilometres, 137 Jovian radii) to Jupiter at this date, and performed many scientific measurements.[6] It also produced the most detailed global color portrait of Jupiter ever produced (seen on the right); the smallest visible features are approximately 60 km (37 mi) across.

2001[edit]

May 30 – During the coast phase between Jupiter and Saturn, it was noticed that "haze" became visible in the pictures taken by the narrow-angle camera of Cassini. This was first seen when a picture of the star Maia in the Pleiades was taken after a routine heating period.

2002[edit]

July 23 – In late January, a test was performed to remove the "haze" from the narrow-angle camera lens by heating it. Warming the camera to 4 degrees Celsius (39 degrees Fahrenheit) for eight days produced positive results. Later, the heating was extended to 60 days, and a picture of the star Spica showed an improvement of more than 90 percent compared to before the heating period. On July 9, a picture showed that the removal procedure was completed successfully, which was announced on July 23.[7]

2003[edit]

October 10 – The Cassini science team announced the results of a test of Einstein's theory of gravity, using radio signals from the Cassini probe. The researchers observed a frequency shift in the radio waves to and from the space craft, as those signals traveled close to the Sun. Past tests were in agreement with the theoretical predictions with an accuracy of one part in one thousand. The Cassini experiment improved this to about 20 parts in a million, with the data still supporting Einstein's theory.

2004[edit]

Cassini image of Saturn, February 2004

February 27 – A new, high-resolution picture of Saturn taken by Cassini on February 9 was released, and it was noted that mission scientists were puzzled by the fact that no "spokes" in Saturn's ring are visible. These dark structures in the "B" section of the ring had been discovered in pictures taken by the Voyager probe in 1981.[8] Another picture, in infrared light, taken on February 16 shows cloud height differences and the same disturbance visible throughout the 1990s in Hubble Space Telescope images.[9]

March 12 – Pictures taken on February 23 do show a feature discovered by Voyager: Clumps in the outer "F"-ring. What could not be ascertained at the time, was the exact lifetime of these clumps, and it is hoped that Cassini will provide conclusive data about this question. The first set of pictures show a set of "clumps" moving along the "F" ring.[10]

March 26 – The Cassini science team published a first sequence of pictures of Saturn showing clouds moving at high speed around the planet. Using a filter to better see water haze on top of the dense cloud cover, motions in the equatorial and southern regions are clearly visible.[11] The pictures were taken during the days from February 15 to February 19.

April 8 – The first "long-term" observation of cloud dynamics in Saturn's atmosphere were published by mission scientists. A set of pictures shows two storms in the southern latitudes merge during a period from March 19 to March 20. Both storms had a diameter of about 1,000 km (620 mi) before they merged.

'F' Ring and shepherd moons

April 15 – NASA announced that two moons discovered by Voyager 1 were sighted again by Cassini in pictures taken on March 10: Prometheus and Pandora. These are no ordinary moons, but their gravitational effects on the "F" ring led scientists to call them "shepherd moons". They fascinate all researchers interested in the dynamics of the ring system, because their orbits are close enough that they interact with each other in a chaotic manner. They have a history of defying predictions of their orbits. One of Cassini's missions will be to monitor the movements of these bodies closely.

May 18Cassini entered the Saturn system. The gravitational pull of Saturn began to overtake the influence of the Sun.

Titan seen from Cassini

May 20 – The first picture of Titan with better resolution than any Earth based observation was released. It was taken May 5 from a distance of 29.3 million kilometers (18.2 million miles).

May 27 – TCM-20, the Phoebe approach TCM (Trajectory Correction Maneuver) was executed at 22:26:00 UTC. This was a 5 minute and 56 second burn of the main engine, which was not used since December 1998. It therefore doubled as a "dress rehearsal" for the 96 minute burn during "Saturn Orbit Insertion" (SOI). However, TCM-20 was mainly designed to change Cassini's velocity by 34.7 m/s (78 mph), setting up a flyby of the moon Phoebe June 11.

This image of Saturn's moon Phoebe was taken by Cassini spacecraft at 16:10 UT on 2004-Jun-11

June 11 – Cassini flew by the moon Phoebe at 19:33 UT in Spacecraft Event Time at 2068 kilometers distance. All of the eleven onboard instruments operated as expected and all data was acquired. Scientists plan to use the data to create global maps of the cratered moon, and to determine Phoebe's composition, mass and density. It will take scientists several days to pore over the data to make more concrete conclusions.

June 16 – TCM-21 took place with a 38 second main engine burn. It was planned as the last correction of the trajectory of Cassini before SOI. A few days later the final TCM-22 tentatively scheduled for June 21 was cancelled.

July 1 – The Saturn Orbit Insertion burn was successfully executed. At 7:11 p.m. PDT (10:11 p.m. EDT), Cassini crossed the ring plane between Saturn's F and G rings. Its antenna was oriented forward acting as a shield against small ring particles. At 7:36 p.m. PDT (10:36 p.m. EDT), the spacecraft began a critical 96-minute main engine burn to cut its velocity by 626 meters per second and permit a 0.02 x 9 million kilometer Saturn orbit. Right after that burn, pictures of the rings were taken and sent back to mission scientist as the spacecraft approached within 19,980 kilometers (12,400 miles) from the cloud tops.[12]

Ring edge as seen by Cassini

Scientists were surprised by the clarity and detail of the pictures and will be poring over them for quite some time. "We won't see the whole puzzle, only pieces, but what we are seeing is dramatic," said Dr. Carolyn Porco, Cassini imaging team leader, Space Science Institute, Boulder, Colo. "The images are mind-boggling, just mind-boggling. I've been working on this mission for 14 years and I shouldn't be surprised, but it is remarkable how startling it is to see these images for the first time."

July 2 – Cassini's first flyby of Titan was executed and first close up pictures were sent back to Earth. Due to the planning of the initial orbit, Cassini was passing over the south pole of the moon and from a larger distance than in later flybys. However, during a press conference on June 3, mission scientist presented pictures that are already forcing them to rethink previous theories. It now seems that the darker and brighter albedo features on the surface do represent different materials. But in contrast to expectation, the icy regions seem to be darker than the areas where other (possibly organic) matter is mixed in with the ice.

August 16 – Mission scientists announce the discovery of two new moons of Saturn, and with it the successful start of one of the programs of Cassini: Locating small and yet unknown moons. Later named "Methone" (S/2004 S 1) and "Pallene" (S/2004 S 2), these objects are small compared to other moons and they orbit between Mimas and Enceladus.

August 23 – At a distance of 9 million kilometers from Saturn, the last major firing of the main engine took place to adjust the next closest approach and avoid the particles in the ring system. The 51 minute burn increased the velocity of the probe by 325 meters per second, moving the orbital periapsis point about 300,000 km farther away from Saturn than its smallest distance during SOI. At the same time, the new course will bring Cassini very close to Titan on its next flyby.[13]

September 14 – Final checkout of the Huygens lander was completed successfully. The separation of the probe stays scheduled for December 25, with the landing anticipated on January 14, 2005.

False color image of Titan

October 26 – The second flyby of Titan (called "Titan-A") was successfully executed. Data started to arrive at the JPL mission center at 01:30 UTC, October 27, and included the highest resolution pictures ever taken of the surface of that moon. Also, first high-resolution infra-red spectra and pictures were taken from the atmosphere and surface. The spacecraft successfully skimmed the hazy, smoggy atmosphere of Titan, coming within 1,176 kilometers of Titan's surface. The flyby was the closest that any spacecraft has ever come to Titan. The pictures, spectra and radar data revealed a complex, puzzling surface. Analysis of all data is on-going. The only glitch during the "Titan-A" event involved the CIRS instrument. During playback the instrument team observed corrupted data. A decision was made to power the instrument off to reboot it. CIRS was powered back on within 24 hours and is currently in its nominal state.

November 23 – The last in-flight checkout of the Huygens probe before separation was completed successfully. All systems are ready for an on-time deployment of the probe.

December 13 – The "Titan-B" flyby was executed successfully and the collected data are analyzed by mission scientists.

December 25 – Huygens probe separated from Cassini orbiter at 02:00 UTC.

Huygens is released on its way to Titan.

December 27 – NASA published a picture of Huygens taken from Cassini two days after release. It reported that the analysis of that picture shows that the probe is on the correct course within the expected error range. These checks were necessary in order to place the orbiter in the correct orientation to receive the data from the probe when it enters Titan's atmosphere.

December 28 – OTM-10 was executed at 03:00 UTC in Spacecraft Event Time. This maneuver, also called the Orbit Deflection Maneuver (ODM), took Cassini off of a Titan-impacting trajectory and on to a flyby trajectory with the required altitude to receive data from the Huygens probe as it plunges into Titan.

December 31 – Cassini's flyby of Iapetus occurred at 18:45:37 UTC at an altitude of 122645 kilometers. First raw pictures were available the next day.

2005[edit]

First picture from the surface of Titan

January 14Huygens entered Titan's atmosphere at 09:06 UTC and had landed softly on its surface about two hours later. This was confirmed by the reception of the carrier wave emitted by the probe during its descent and touchdown. At 16:19 UTC the Cassini orbiter started to relay to Earth the scientific data received from the probe. The first picture was released at 19:45 UTC, showing a view from about 16 km above the surface. A second picture taken from the probe at rest on the surface was released a short time later. Analysis of the data is ongoing.

February 15 – Successful Titan flyby, with new regions of its surface scanned by radar. Cassini 's mapping RADAR acquired a picture that shows a large crater on Titan, with an estimated diameter of 440 km (270 mi).[14]

First closeup view of Enceladus

February 17 – The first close flyby of Enceladus was executed and first closeup images were sent back to Earth. The flyby distance was about 1,180 km (730 mi).

March 9 – The second flyby of Enceladus was performed and Cassini passed the moon with minimum distance of 500 km (310 mi).

March 17 – The Cassini probe reveals that Saturn's moon Enceladus has an atmosphere. It has been described as "substantial" by its discoverers.

March 31 – The fourth planned flyby of Titan with a minimum distance of about 2400 kilometers was executed. Images and other data are currently being evaluated.[15]

Mass plot for Titan's atmosphere

April 16 – The fifth planned flyby of Titan with a minimum distance of about 1025 kilometers was executed at 19:12 UTC. This was the closest flyby up to this date, and provided the opportunity to obtain more detailed data on the constituents in the upper atmosphere of Titan. A first analysis of that data showed a large range of complex carbon molecules. On April 25 a mass plot was published that demonstrates the existence of these molecules.

May 3 – Cassini begins Radio occultation experiments on Saturn's Rings, to determine ring particle size distribution, on the scale of centimetres.

May 10 – At the beginning of a period focussed observation of the ring system of Saturn, slated to take until September, mission scientist announced the discovery of a new moon in the "Keeler gap" inside the "A" ring. Provisionally named S/2005 S 1 and later named Daphnis, it was first seen in a time-lapse sequence of images taken on May 1. Imaging scientists had predicted the new moon's presence and its orbital distance from Saturn after last July's sighting of a set of peculiar spiky and wispy features in the Keeler gap's outer edge.

July 14 – The closest flyby of Enceladus with a distance of 175 km (109 mi) was executed successfully. First raw pictures were published.

August 22 – Flyby of Titan with a minimum distance of 3,669 km (2,280 mi).[16]

September 7 – Flyby of Titan at a distance of 1,075 km (668 mi), data gathered partially lost due to software problem.

September 24 – Flyby of Tethys at a distance of 1,500 km (930 mi).

September 26 – Flyby of Hyperion at a distance of 1,010 km (630 mi), the closest flyby and only visit to the moon during the primary mission.

October 11 – Flyby of Dione at a distance of 500 km (310 mi).

October 28 – Flyby of Titan at a distance of 1,400 km (870 mi).

November 26 – Flyby of Rhea at a distance of 500 km (310 mi).

December 26 – Flyby of Titan at a distance of 10,410 km (6,470 mi).[17]

2006[edit]

An eclipse of Saturn with the rings visible, taken in 2006

January 15 – Flyby of Titan at a distance of 2,040 km (1,270 mi).[18]

February 27 – Flyby of Titan at a distance of 4,390 km (2,730 mi).[19]

March 18 – Flyby of Titan at a distance of 1,950 km (1,210 mi).[20]

May 20 – Flyby of Titan at a distance of 1,880 km (1,170 mi).[21]

July 2 – Flyby of Titan at a distance of 1,910 km (1,190 mi).[22]

July 27 – NASA confirms the presence of hydrocarbon lakes in Titan's northern polar region.

September 23 – Flyby of Titan at a distance of 960 km (600 mi).[23]

One of the images of Saturn released by NASA on March 1, 2007. The image was taken on January 19 of that year.

2007[edit]

March 1 – NASA releases several remarkable images of Saturn from Cassini, many in angles not possible from Earth.[24]

September 10 – Flyby of Iapetus at a distance of 1,600 km (990 mi).

2008[edit]

Mar 12 — Cassini is scheduled to do an unprecedented "in your face" flyby of Saturn's moon Enceladus.[25]

May 28 – Cassini completed its 43rd flyby of Titan, ending its primary mission. Renamed Cassini Equinox mission, Cassini will observe Saturn during its equinox crossing, or summertime.[26] and the probe is capable of at least a second mission extension beyond that, tentatively named "Cassini Solstice mission".

Cassini Equinox mission[edit]

Rings from above, with Saturn cropped

Aug 11, October 9, 31 – With closest approach at 50, 25, and 200 km, respectively, Cassini's last three Enceladus flybys of 2008 utilized a new imaging technique named "skeet shooting" to successfully acquire very high resolution images. The flybys also allowed Cassini to directly sample Enceladus's cryovolcanic plumes.

'Nov 3, 14, Dec 5, 21 – Titan flybys 46 through 49 concentrated on RADAR, VIMS, and INMS sampling of Titan and its thick atmosphere. T47 involved high-resolution VIMS coverage of the Huygens landing site, while the other three flybys made use of RADAR and RSS. T49 allowed RADAR coverage of Ontario Lacus, one of the largest methane lakes on Titan.

2009[edit]

During 2009 Cassini will make 15 flybys of Titan and 2 close flybys of Enceladus. From June to October Cassini will observe Saturn during its equinox, or the time of Saturn's year where the sun is directly over its equator. Along with Titan and Enceladus, 2010 will also see very close flybys of Rhea (100 km), Dione (313 km), and Helene (1,133 km). Tethys, Telesto and Mimas will be observed at relatively close range as well, with Cassini coming within 10,000 km of Mimas (the closest approach of the mission). If conditions permit, Cassini may be able to acquire high resolution images of Methone, Pallene, Anthe, Calypso, Polydeuces, and Aegaeon.[27]

2010[edit]

On November 2, 2010, Cassini was triggered into a protective standby mode, or "safe mode", after a bit flip caused it to miss an important instruction. NASA announced the interruption in scientific processes on November 8.[28] However, by November 8 some of the craft's functionality had already been partly restored.[29] Nominal scientific instrument sequencing events were successfully started on November 10.[30][31] Cassini was reactivated as scheduled on November 24 and has returned to perfect working order, in time for two scheduled close fly-bys with Enceladus.[32] At this point there has been no public disclosure[33] as to the data loss impact of the November 11 (T-73) flyby. However, no images were acquired at the 11 November polar flyby.

Cassini made two close flybys of Enceladus in December.

Cassini Solstice Mission (2010-2017)[edit]

In 2010, Feb. 3, NASA announced that a second mission extension until May 2017, a few months past Saturn's summer solstice, had been funded. The schedule includes an additional 155 orbits, with 54 flybys of Titan, 11 of Enceladus,[34] 2 of Rhea, and 3 of Dione. One of the flybys of Titan will dip below the ionosphere.

Cassini flew by Saturn's little moon Methone in May 2012

Cassini orbiter travel milestones[edit]

Spacecraft event time Distance from Saturn
2004-Mar-22 07:42:14 50,000,000 kilometers
2004-Apr-12 19:35:12 40,000,000 kilometers
2004-May-04 02:59:09 30,000,000 kilometers
2004-May-25 02:40:06 20,000,000 kilometers
2004-Jun-14 11:15:22 10,000,000 kilometers

Detailed timeline of Huygens mission[edit]

Main article: Huygens (spacecraft)
Huygens's distance from Titan[35]

All times given after 2005-Jan-14 09:11 UTC are expected event times and may differ from actual event times. This page will be updated after descent has occurred with corrections if they are necessary.

The data used in this section has been slightly out of date, an updated version of ephemeris from ESA was available 2005 January 6.[citation needed]


Huygens probe travel milestones[edit]

Spacecraft event time Description
2004-Dec-25 02:00 UTC Huygens separates from Cassini
2004-Dec-25 06:07 UTC 5 kilometers from Cassini
2004-Dec-25 10:13 UTC 10 kilometers from Cassini
2004-Dec-28 01:17 UTC 100 kilometers from Cassini
2004-Dec-28 12:20 UTC 1,000 kilometers from Cassini
2004-Dec-29 00:02 UTC 2,000 kilometers from Cassini
2004-Dec-29 11:39 UTC 3,000 kilometers from Cassini
2004-Dec-29 23:11 UTC 4,000 kilometers from Cassini
2004-Dec-30 10:36 UTC 5,000 kilometers from Cassini
2005-Jan-03 20:01 UTC 4,658,661 kilometers from Titan (farthest distance)
2005-Jan-06 23:40 UTC 4,000,000 kilometers from Titan
2005-Jan-09 01:26 UTC 3,000,000 kilometers from Titan
2005-Jan-10 18:37 UTC 2,000,000 kilometers from Titan
2005-Jan-12 11:20 UTC 1,000,000 kilometers from Titan
2005-Jan-12 15:36 UTC 900,000 kilometers from Titan
2005-Jan-12 19:56 UTC 800,000 kilometers from Titan
2005-Jan-13 00:19 UTC 700,000 kilometers from Titan
2005-Jan-13 04:48 UTC 600,000 kilometers from Titan
2005-Jan-13 09:21 UTC 500,000 kilometers from Titan
2005-Jan-13 13:59 UTC 400,000 kilometers from Titan
2005-Jan-13 18:43 UTC 300,000 kilometers from Titan
2005-Jan-13 23:31 UTC 200,000 kilometers from Titan
2005-Jan-14 04:23 UTC 100,000 kilometers from Titan
2005-Jan-14 04:53 UTC 90,000 kilometers from Titan
2005-Jan-14 05:22 UTC 80,000 kilometers from Titan
2005-Jan-14 05:52 UTC 70,000 kilometers from Titan
2005-Jan-14 06:21 UTC 60,000 kilometers from Titan
2005-Jan-14 06:50 UTC 50,000 kilometers from Titan
2005-Jan-14 07:20 UTC 40,000 kilometers from Titan
2005-Jan-14 07:49 UTC 30,000 kilometers from Titan
2005-Jan-14 08:18 UTC 20,000 kilometers from Titan
2005-Jan-14 08:48 UTC 10,000 kilometers from Titan
2005-Jan-14 08:51 UTC 9,000 kilometers from Titan
2005-Jan-14 08:54 UTC 8,000 kilometers from Titan
2005-Jan-14 08:57 UTC 7,000 kilometers from Titan
2005-Jan-14 08:59 UTC 6,000 kilometers from Titan
2005-Jan-14 09:02 UTC 5,000 kilometers from Titan
2005-Jan-14 09:06 UTC Huygens enters the atmosphere of Titan
2005-Jan-14 11:24 UTC Huygens impacts with the surface of Titan

Celestial phenomena as seen from the landing site in the landing (Titan's) day[edit]

The landing day begins at 2005-Jan-08 04:05:08 UTC and ends at 2005-Jan-24 03:26:14 UTC.

According to Huygens predicted descent trajectory provided by ESA/JPL, valid as of January 6, 2005, the probe was projected to land at 10.2936 degrees south and 163.1775 degrees east. Prior to the landing, the location of the landing site could not be known exactly, since the probe was influenced by wind in Titan's atmosphere as it descended.

Local apparent solar time Spacecraft event time Description
03:06 2005-Jan-10 05:43 UTC Jupiter rises
03:21 2005-Jan-10 09:43 UTC Phoebe sets
03:55 2005-Jan-10 18:47 UTC Pluto rises
04:56 2005-Jan-11 10:54 UTC Cassini rises
05:03 2005-Jan-11 12:52 UTC Huygens rises
05:06 2005-Jan-11 13:29 UTC Mars rises
05:29 2005-Jan-11 19:36 UTC Venus rises
05:31 2005-Jan-11 20:19 UTC Mercury rises
05:35 2005-Jan-11 21:22 UTC Iapetus rises
05:43 2005-Jan-11 23:20 UTC Sun rises
05:44 2005-Jan-11 23:39 UTC Earth rises
05:44 2005-Jan-11 23:40 UTC Moon rises
06:52 2005-Jan-12 17:54 UTC Neptune rises
07:47 2005-Jan-13 08:32 UTC Uranus rises
08:26 2005-Jan-13 18:46 UTC Earth transit across Sun (1st contact)
08:26 2005-Jan-13 18:53 UTC Earth transit across Sun (2nd contact)
08:35 2005-Jan-13 21:20 UTC Moon transit across Sun (1st contact)
08:36 2005-Jan-13 21:22 UTC Moon transit across Sun (2nd contact)
08:48 2005-Jan-14 00:34 UTC Earth transit across Sun (Greatest)
08:58 2005-Jan-14 03:13 UTC Moon transit across Sun (Greatest)
09:09 2005-Jan-14 06:15 UTC Earth transit across Sun (3rd contact)
09:09 2005-Jan-14 06:23 UTC Earth transit across Sun (4th contact)
09:12 2005-Jan-14 07:10 UTC Cassini transit the meridian
09:20 2005-Jan-14 09:03 UTC Moon transit across Sun (3rd contact)
09:20 2005-Jan-14 09:05 UTC Moon transit across Sun (4th contact)
09:20 2005-Jan-14 09:06 UTC Huygens enters the atmosphere
09:28 2005-Jan-14 11:11 UTC Jupiter transit the meridian
09:28 2005-Jan-14 11:24 UTC Huygens impacts with the surface
09:35 2005-Jan-14 13:08 UTC Cassini sets
10:11 2005-Jan-14 22:41 UTC Pluto transit the meridian
10:23 2005-Jan-15 01:48 UTC Hyperion sets
11:14 2005-Jan-15 15:27 UTC Iapetus transit the meridian
11:26 2005-Jan-15 18:36 UTC Mars transit the meridian
11:48 2005-Jan-16 00:36 UTC Venus transit the meridian
11:50 2005-Jan-16 01:09 UTC Mercury transit the meridian
11:59 2005-Jan-16 03:26 UTC Earth transit the meridian
11:59 2005-Jan-16 03:27 UTC Moon transit the meridian
12:00 2005-Jan-16 03:44 UTC Sun transit the meridian
13:05 2005-Jan-16 21:02 UTC Neptune transit the meridian
13:56 2005-Jan-17 10:39 UTC Uranus transit the meridian
15:49 2005-Jan-18 16:41 UTC Jupiter sets
16:26 2005-Jan-19 02:24 UTC Phoebe rises
16:26 2005-Jan-19 02:36 UTC Pluto sets
17:46 2005-Jan-19 23:42 UTC Mars sets
17:55 2005-Jan-20 02:08 UTC Iapetus sets
18:08 2005-Jan-20 05:35 UTC Venus sets
18:10 2005-Jan-20 06:06 UTC Mercury sets
18:14 2005-Jan-20 07:20 UTC Earth sets
18:14 2005-Jan-20 07:21 UTC Moon sets
18:17 2005-Jan-20 08:09 UTC Sun sets
19:18 2005-Jan-21 00:10 UTC Neptune sets
20:05 2005-Jan-21 12:46 UTC Uranus sets
21:31 2005-Jan-22 11:44 UTC Phoebe transit the meridian



Timeline of Huygens landing process[edit]

Spacecraft event time Description
2005-Jan-11 12:00 UTC Orbiter rise in the east (azimuth = 93 degrees) as seen from the landing site
2005-Jan-14 06:50 UTC Orbiter turns on probe radio link receivers
2005-Jan-14 07:02 UTC Orbiter begins to turn radio dish toward Titan
2005-Jan-14 07:14 UTC Orbiter turn to Titan complete; 3 minutes later orbiter X-band downlink disabled
2005-Jan-14 08:29 UTC Saturn occulted by Titan as seen from Huygens
2005-Jan-14 08:38 UTC Saturn's rings occulted by Titan as seen from Huygens
2005-Jan-14 08:44 UTC Probe turns transmitters on; low power mode
2005-Jan-14 09:06 UTC Huygens enters the atmosphere of Titan
2005-Jan-14 09:09 UTC Huygens feels maximum deceleration
2005-Jan-14 09:10 UTC Deploy pilot chute
2005-Jan-14 09:10 UTC Release aft cover
2005-Jan-14 09:10 UTC Deploy main parachute
2005-Jan-14 09:11 UTC Begin transmission to Cassini orbiter
2005-Jan-14 09:11 UTC Release front shield; transmitters switch to high power mode; instruments configured for descent and measurements commence
2005-Jan-14 09:25 UTC Main parachute separates; deploy stabilizing drogue chute
2005-Jan-14 09:42 UTC Surface proximity sensor activated
2005-Jan-14 09:49 UTC Possible icing effects on probe
2005-Jan-14 09:50 UTC Gas Chromatograph Mass Spectrometer begins sampling atmosphere
2005-Jan-14 11:12 UTC Orbiter makes its closest flyby of Titan at an altitude of 59996 kilometers at a speed of 5401 meters per second and 93 degree phase angle (azimuth = 278 degrees, elevation = 33 degrees as seen from the landing site)
2005-Jan-14 11:23 UTC Turn on descent imager lamp
2005-Jan-14 11:24 UTC Huygens impact with surface of Titan
2005-Jan-14 13:11 UTC Orbiter sets in the west (azimuth = 272 degrees) as seen from the landing site
2005-Jan-14 13:37 UTC Orbiter stops probe data collection

Fly-bys[edit]

Following is a list of close fly-bys of Saturn's moons (at less than 5000 km). The closest approach for each moon is bolded.

Primary mission[edit]

Body Date (UTC) Altitude (kilometer)
Phoebe 2004 Jun 11 19:33 1,997
Passage through rings 2004 Jun 30 (twice) 0
Titan 2004 Oct 26 15:30 1,200
Titan 2004 Dec 13 11:38 1,200
Probe Release 2004 Dec 25 02:00
Titan 2005 Feb 15 06:58 1,577
Enceladus 2005 Feb 17 03:30 1,176
Polydeuces 2005 Feb 17 08:48 6,447
Enceladus 2005 Mar 09 09:08 500
Titan 2005 Mar 31 20:05 2,402
Titan 2005 Apr 16 19:12 1,025
Enceladus 2005 Jul 14 19:58 175
Titan 2005 Aug 22 08:53 3,758
Titan 2005 Sep 07 08:01 1,025
Tethys 2005 Sep 24 01:36 1,500
Hyperion 2005 Sep 26 01:46 500
Dione 2005 Oct 11 17:59 500
Titan 2005 Oct 28 04:04 1,451
Rhea 2005 Nov 26 22:37 500
Titan 2006 Jan 15 11:41 2,043
Titan 2006 Feb 27 08:25 1,813
Titan 2006 Mar 19 00:06 1,951
Titan 2006 Apr 30 20:58 1,855
Titan 2006 May 20 12:18 1,879
Titan 2006 Jul 02 09:21 1,906
Titan 2006 Jul 22 00:25 950
Titan 2006 Sep 07 20:13 950
Methone 2006 Sep 09 19:17 15,100
Titan 2006 Sep 23 18:54 950
Titan 2006 Oct 09 17:25 950
Titan 2006 Oct 25 15:53 950
Titan 2006 Dec 12 11:37 950
Titan 2006 Dec 28 10:02 1,500
Titan 2007 Jan 13 08:36 950
Titan 2007 Jan 29 07:13 2,726
Titan 2007 Feb 22 03:10 950
Titan 2007 Mar 10 01:47 950
Titan 2007 Mar 26 00:21 950
Titan 2007 Apr 10 22:57 950
Titan 2007 Apr 26 21:31 950
Titan 2007 May 12 20:08 950
Titan 2007 May 28 18:51 2,426
Titan 2007 Jun 13 17:46 950
Titan 2007 Jun 29 17:02 1,944
Titan 2007 Jul 19 00:37 1,300
Titan 2007 Aug 31 06:35 3,212
Iapetus 2007 Sep 10 12:34 1,227
Titan 2007 Oct 02 04:54 950
Titan 2007 Nov 19 00:58 950
Titan 2007 Dec 05 00:06 1,300
Titan 2007 Dec 20 22:53 950
Titan 2008 Jan 05 21:25 950
Methone 2008 Jan 15 21:11 15,600
Titan 2008 Feb 22 17:39 950
Enceladus 2008 Mar 12 19:07 1,000
Titan 2008 Mar 25 14:35 950
Titan 2008 May 12 10:10 950
Pallene 2008 May 25 22:06 28,000
Titan 2008 May 28 08:33 1,348
Janus 2008 Jun 30 08:58 30,000

Extended (Equinox) mission[edit]

Body Date (UTC) Altitude (kilometers)
Titan 2008 Jul 31 02:13 1,613
Enceladus 2008 Aug 11 21:06 54
Enceladus 2008 Oct 9 19:07 25
Pallene 2008 Oct 17 02:58 29,000
Enceladus 2008 Oct 31 17:15 197
Titan 2008 Nov 3 17:35 1,100
Titan 2008 Nov 19 15:56 1,023
Titan 2008 Dec 5 14:26 960
Titan 2008 Dec 21 13:00 970
Titan 2009 Feb 7 08:51 960
Titan 2009 Mar 27 04:44 960
Titan 2009 Apr 4 01:48 4,150
Titan 2009 Apr 20 00:21 3,600
Titan 2009 May 5 22:54 3,244
Titan 2009 May 21 21:27 965
Titan 2009 Jun 6 20:00 965
Titan 2009 Jun 22 18:33 955
Titan 2009 Jul 8 17:04 965
Titan 2009 Jul 24 15:34 955
Titan 2009 Aug 9 14:04 970
(Equinox) 2009 Aug 11 (Sun illuminates north
side of rings)
Titan 2009 Aug 25 12:52 970
Titan 2009 Oct 12 08:36 1,300
Enceladus 2009 Nov 2 07:42 99
Enceladus 2009 Nov 21 02:10 1,603
Titan 2009 Dec 12 01:03 4,850
Titan 2009 Dec 28 00:17 955
Titan 2010 Jan 12 23:11 1,073
Calypso 2010 Feb 13 11:45 21,000
Rhea 2010 Mar 2 17:41 101
Helene 2010 Mar 3 13:41 1,823
Dione 2010 Apr 7 05:16 503
Enceladus 2010 Apr 28 00:11 99
Enceladus 2010 Apr 28 00:11 198
Titan 2010 Apr 28 00:11 1,400
Titan 2010 Jun 5 02:26 2,044
Titan 2010 Jun 21 01:27 880 (below the ionosphere)
Titan 2010 Jul 07 1,005
Kiviuq (light-curve data) 2010 July 15 9.3 million
Albiorix (light-curve data) 2010 July 31  ?? million
Enceladus 2010 Aug 13 2,554

Solstice mission[edit]

The second extended mission is scheduled from 2010 October 12 through the Saturnian summer solstice in May 2017, followed by two dozen proximal orbits of Saturn and the rings. The Cassini mission will end in 2017 September 15, when the craft is planned to be plunged into the Saturnian atmosphere.

Body Date (UTC) Altitude (kilometers)
Enceladus 2010 Nov 30 48
Enceladus 2010 Dec 21 01:08 48
Rhea 2011 Jan 11 04:53 76
Titan 2011 Feb 18 16:04 3,651
Telesto 2011 Mar 20 10,000
Titan 2011 May 8 22:54 1,873
Titan 2011 Jun 20 1,359
Pallene 2011 Sep 14 26,000
Enceladus 2011 Oct 1 99
Enceladus 2011 Oct 19 1,231
Enceladus 2011 Nov 6 496
Dione 2011 Dec 12 09:39 99
Titan 2011 Dec 13 3,586
Titan 2012 Feb 19 3,803
Enceladus 2012 Mar 27 74
Enceladus 2012 Apr 14 74
Enceladus 2012 May 2 74
Telesto 2012 May 20 11,000
Methone 2012 May 20–21 1900[36]
Titan 2012 May 22 955
Titan 2012 Jun 7 959
Titan 2012 Jul 24 1,012
Titan 2012 Sep 26 14:36 956
Titan 2012 Nov 13 10:22 973
Titan 2012 Nov 29 08:57 1,014
Titan 2013 Feb 17 01:57 1,978
Rhea 2013 Mar 9 18:17 997
Titan 2013 Apr 5 21:44 1,400
Titan 2013 May 23 17:33 970
Titan 2013 Jul 10 13:22 964
Titan 2013 Jul 26 11:56 1,400
Titan 2013 Sep 12 07:44 1,400
Titan 2013 Oct 14 04:56 961
Titan 2013 Dec 1 00:41 1,400
Titan 2014 Jan 1 22:00 1,400
Titan 2014 Feb 2 19:13 1,236
Titan 2014 Mar 6 16:27 1,500
Titan 2014 Apr 7 13:41 963
Titan 2014 May 17 16:12 2,994
Titan 2014 Jun 18 13:28 3,659
Titan 2014 Aug 21 08:09 964
Titan 2014 Sep 22 05:23 1,400
Titan 2014 Oct 24 02:41 1,013
Titan 2014 Dec 10 22:27 980
Titan 2015 Feb 12 17:08 1,200
Titan 2015 Feb 12 17:08 1,200
Titan 2015 Mar 16 14:30 2,274
Titan 2015 May 7 22:50 2,722
Dione 2015 Jun 16 20:12 516
Dione 2015 Aug 17 18:33 474
Titan 2015 Sep 28 21:37 1,036
Enceladus 2015 Oct 14 10:42 1,839
Enceladus 2015 Oct 28 15:23 49
Epimetheus 2015 Dec 6 2,616
Prometheus 2015 Dec 6 21,000
Aegaeon 2015 Dec 19 2,556
Enceladus 2015 Dec 19 17:49 5,000
Titan 2016 Feb 1 01:01 1,400
Titan 2016 Feb 16 23:52 1,018
Titan 2016 Apr 4 19:48 990
Titan 2016 May 6 17:01 971
Titan 2016 Jun 7 14:13 975
Titan 2016 Jul 25 10:05 976
Titan 2016 Sep 27 04:23 1,736
Titan 2016 Nov 14 00:02 1,582
Proximal orbits
Body Date (UTC) Altitude (kilometers)
Titan 2016 Nov 29 3,223
Pandora 2016 Dec 18 13,800
Daphnis 2017 Jan 16 17,800
Pan 2017 Mar 7 25,000
Atlas 2017 Apr 12 14,800

Trajectory[edit]

The initial gravitational-assist trajectory of Cassini–Huygens is the process whereby an insignificant mass approaches a significant mass "from behind" and "steals" some of its orbital momentum. The significant mass, usually a planet, loses a very small proportion of its orbital momentum to the insignificant mass, the space probe in this case. However, due to the space probe's small mass, this momentum transfer gives it a relatively large velocity increase in proportion to its initial velocity, speeding up its travel through outer space.

The Cassini–Huygens space probe performed two gravitational assist fly-bys at Venus, one more fly-by at the Earth, and a final fly-by at Jupiter.

The initial gravitational-assist trajectory of Cassini–Huygens
The Cassini craft's speed relative to the Sun. The various gravitational slingshots form visible peaks on the left, while the periodic variation on the right is caused by the spacecraft's orbit around Saturn. The data came from the JPL Horizons Ephemeris System in 2005. The speed above is instantaneous velocity in kilometers per second. The minimum velocity achieved during its Saturnian orbit is more or less equal to Saturn's own orbital velocity, which is the ~5.0 km/s velocity which the Cassini craft matched to enter orbit.



References[edit]

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External links[edit]