Timeline of Cassini–Huygens

[1][2] The Flagship-class uncrewed robotic spacecraft comprised both NASA's Cassini probe, and ESA's Huygens lander which was designed to land on Saturn's largest moon, Titan.

Launched aboard a Titan IVB/Centaur on 15 October 1997, Cassini had a nearly 20-year life span, with 13 of these years spent orbiting Saturn.

[3] The voyage to Saturn included flybys of Venus (April 1998 and June 1999), Earth (August 1999), the asteroid 2685 Masursky, and Jupiter (December 2000).

The Huygens module traveled with Cassini until its separation from the probe on 25 December 2004; it was successfully landed by parachute on Titan on 14 January 2005.

15 October 1997 01:43 Pacific Daylight Time (PDT) – Cassini launched at 08:43 UTC inside Titan IVB/Centaur rocket at Cape Canaveral.

[10] 3 December 1998 22:06 PST – Cassini fired its main rocket engine for 90 minutes, setting the spacecraft on course for its second Venus flyby in 1999.

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 was at its closest point (9.7 million kilometres, 137 Jovian radii) to Jupiter at this date, and performed many scientific measurements.

The researchers observed a frequency shift in the radio waves to and from the space craft, as those signals traveled close to the Sun.

[17] Another picture, in infrared light, taken on 16 February shows cloud height differences and the same disturbance visible throughout the 1990s in Hubble Space Telescope images.

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.

[19] 26 March 2004 – The Cassini science team published the 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.

15 April 2004 – NASA announced that two moons discovered by Voyager 1 were sighted again by Cassini in pictures taken on 10 March: Prometheus and Pandora.

Scientists plan to use the data to create global maps of the cratered moon, and to determine Phoebe's composition, mass and density.

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.

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.

Regardless, during a press conference on 3 June,[clarification needed] mission scientists presented pictures that were already causing them to rethink previous theories.

23 August 2004 – 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.

Data started to arrive at the JPL mission center at 01:30 UTC, 27 October, and included the highest resolution pictures ever taken of the surface of that moon.

These checks were necessary in order to place Cassini in the correct orientation to receive the data from Huygens when it entered Titan's atmosphere.

Cassini's mapping radar acquired a picture that shows a large crater on Titan, with an estimated diameter of 440 km (270 mi).

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.

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.

7 September 2005 – Flyby of Titan at a distance of 1,075 km (668 mi), data gathered partially lost due to software problem.

On 3 February 2010, NASA announced that a second mission extension until May 2017, a few months past Saturn's summer solstice, had been funded.

On 15 September 2017, Cassini was deliberately disposed of by a controlled fall into Saturn's atmosphere, ending its nearly two-decade-long mission.

The second extended mission was scheduled from 2010 October 12 through the Saturnian summer solstice in May 2017, followed by two dozen proximal orbits of Saturn and the rings.