In Cassini’s Grand Finale orbits — the final orbits of its nearly 20-year mission — the spacecraft travels in an elliptical path that sends it diving at tens of thousands of miles per hour through the 1,500-mile-wide (2,400-kilometer) space between the rings and the planet where no spacecraft has ventured before.

End of Mission: 15 Sep 2017

Each of these last 22 orbits takes about six and a half days to complete. They begin April 22 and end Sept. 15. When Cassini is nearest to Saturn during each orbit, the spacecraft’s speed ranges between 75,000 and 78,000 miles per hour (121,000 and 126,000 kilometers per hour), depending on the orbit.

The Grand Finale orbits are so named because they not only carry Cassini to its end, but because they are truly grand. The spacecraft flies through an unexplored region of the Saturnian system, producing unique images and attempting to solve longtime mysteries, such as the mass of Saturn’s rings and the planet’s rotation rate — the length of a Saturn day. And then during Cassini’s last five orbits, the spacecraft dips down to directly sample Saturn’s upper atmosphere.

The summaries posted on this page for each Grand Finale orbit include only a few highlights of the many unparalleled science investigations that Cassini performs during these unprecedented orbits. Also, because Saturn is a gas giant, Cassini can’t be described as being a certain distance from the planet’s “surface.” So, to convey Cassini’s distance from Saturn, each summary also includes the spacecraft’s closest approach to Saturn’s 1-bar level for that orbit. A bar is the atmospheric pressure you experience on Earth at sea level.

A short, animated video describing Cassini's Grand Finale. Download ›

Full List of Orbits: 

COMPLETED: Orbit 271 - April 23 - 29

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Apr 23 3:46 a.m. 8:46 p.m. (Apr 22) Official start of the Grand Finale orbits.
Ring Crossing #1 Apr 26 9:00 a.m. 2:00 a.m. First pass through the gap between Saturn's atmosphere and innermost ring. High Gain Antenna will be used as a shield to protect from possible ring particle impacts.
Downlink Apr 27 5:52 a.m. 10:52 p.m. (Apr 26) Estimated Earth Received Time (ERT) is 12:10 a.m. on Apr 27.

This first Grand Finale orbit begins following a final close flyby of Titan that sends Cassini on its first plunge through the gap between Saturn and its rings.

  • Prior to the periapse pass over Saturn, the spacecraft’s Visible and Infrared Mapping Spectrometer (VIMS) captures images to produce a high-resolution movie of Saturn’s north polar region, including the planet’s hexagon jet stream for nearly a full rotation of Saturn.
  • The orbit provides Cassini with its best look ever at Saturn’s north pole with both VIMS and the Composite Infrared Spectrometer (CIRS). And the observations should provide the sharpest near-infrared movies to date of the motion in and around the hexagon.
  • Before Cassini passes through Saturn’s ring plane for the first time in the region between Saturn and its rings, the spacecraft changes its attitude so that its high-gain antenna faces forward (called “HGA to RAM”) to help shield the spacecraft from ring particles during ring-plane crossing.
  • Using its VIMS and Ultraviolet Imaging Spectrograph (UVIS) instruments, Cassini studies Saturn’s smallest ring particles as they pass between the sun and the spacecraft.
  • During the hour leading up to closest approach to Saturn, the imaging cameras (ISS) take a strip-like series of images of features in the atmosphere (which the team refers to as "the noodle"). These images are expected to be Cassini's closest views of Saturn thus far, with a resolution up to 10 times higher than before.
  • During this orbit, Cassini gets within 1,840 miles (2,950 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,960 miles (4,760 kilometers) of the inner edge of Saturn’s D ring.

COMPLETED: Orbit 272 - April 29 - May 6

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Apr 29 2:22 p.m. 7:22 a.m.  
Ring Crossing #2 May 2 7:38 p.m. 12:38 p.m.  
Downlink May 3 2:13 p.m. 7:13 a.m. Estimated Earth Received Time (ERT) is 8:30 a.m. on May 3.
  • During this orbit, Cassini rolls to calibrate its magnetometer (MAG) for the high-intensity magnetic field observations to be performed when the spacecraft is nearest Saturn. This is the first time MAG has made this sort of observation.
  • Cassini’s imaging cameras, the Imaging Science Subsystem (ISS), takes advantage of the last opportunity to observe Saturn's rings at extremely high phase angles while the Sun is hidden behind Saturn, allowing the instrument to survey faint ringlets in the main rings, many of which are difficult to observe outside of this geometry. The ISS also collects images to produce a movie to monitor various structures in Saturn’s D ring.
  • The spacecraft’s Composite Infrared Spectrometer (CIRS) observes Saturn’s moon Rhea in infrared to narrow down the composition and structure of the moon’s surface material.
  • During this orbit, Cassini gets within 1,820 miles (2,930 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,980 miles (4,780 kilometers) of the inner edge of Saturn’s D ring.

COMPLETED: Orbit 273 - May 6 - 12

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse May 6 12:59 a.m. 5:59 p.m. (May 5)  
Ring Crossing #3 May 9 6:13 a.m. 11:13 p.m. (May 8)  
Downlink May 9 6:13 a.m. 11:13 p.m. (May 8) Cassini will be communicating with Earth during the crossing. Estimated Earth Received Time (ERT) is 12:29 a.m. PDT on May 9.

COMPLETED: Orbit 274 - May 12 - 18

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse May 12 11:30 a.m. 4:30 a.m.  
Ring Crossing #4 May 15 4:42 p.m. 9:42 a.m.  
Downlink May 15 4:42 p.m. 9:42 a.m. Cassini will be communicating with Earth during the crossing. Estimated Earth Received Time (ERT) is 10:58 a.m. PDT on May 15.
  • During this Grand Finale orbit, Cassini’s visible-light camera, the Imaging Science Subsystem (ISS), observes Saturn’s most prominent ring propeller features.
  • Next, the Radio Science Subsystem (RSS) takes advantage of one of the best opportunities in the mission to conduct radio occultations of Saturn’s ring system and run a gravity experiment to study Saturn's gravitational field with unprecedented detail. The experiment aims to discover how spherical Saturn’s gravity field is, which helps scientists measure the mass of Saturn’s rings, a figure that is not precisely known.
  • During the radio science/gravity observations, the spacecraft’s Cosmic Dust Analyzer (CDA) scoops up and analyzes small ring particles to help determine the age of Saturn’s rings. Interplanetary meteoroids bombard Saturn’s main rings, depositing silicates, organics, and metals in the ring particles. The more of those contaminants the CDA finds, the older Saturn’s rings probably are.
  • During this orbit, Cassini gets within 1,650 miles (2,660 kilometers) of Saturn’s 1-bar level. Cassini also passes within 3,110 miles (5,000 kilometers) of the inner edge of Saturn’s D ring.

COMPLETED: Orbit 275 - May 18 - 25

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse May 18 9:59 p.m.. 2:59 p.m.  
Ring Crossing #5 May 22 3:11 a.m. 8:11 p.m. (May 21)  
Downlink May 22 3:11 a.m. 8:11 p.m. (May 21) Cassini will be communicating with Earth during the ring crossing. Estimated Earth Received Time (ERT) is 9:26 p.m. PDT on May 21.
  • This orbit, like the previous one, is one of the best opportunities in the mission for the Radio Science Subsystem (RSS) to conduct radio occultations of Saturn’s ring system and run a gravity experiment to study Saturn's gravitational field with unprecedented detail. The experiment helps clarify how spherical Saturn’s gravity field is, but also helps scientists measure the mass of Saturn’s rings, a figure that is not precisely known.
  • And as with the previous orbit, the spacecraft’s Cosmic Dust Analyzer (CDA) scoops up and analyzes ring particles — this time larger ring particles rather than the relatively small particles — to help determine the age of Saturn’s rings. Interplanetary meteoroids bombard Saturn’s main rings, depositing silicates, organics, and metals in the ring particles. The more of those contaminants the CDA finds, the older Saturn’s rings probably are.
  • Also on this orbit, the spacecraft’s Imaging Science Subsystem (ISS), Composite Infrared Spectrometer (CIRS), and Visible and Infrared Mapping Spectrometer (VIMS) observe and map Saturn’s atmosphere, studying the different temperatures of the atmospheric layers, as well as the atmosphere’s composition.
  • During this orbit, Cassini gets within 1,680 miles (2,700 kilometers) of Saturn’s 1-bar level. Cassini also passes within 3,120 miles (5,010 kilometers) of the inner edge of Saturn’s D ring.

COMPLETED: Orbit 276 - May 25 - 31

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse May 25 8:50 a.m. 1:50 a.m.  
Ring Crossing #6 May 28 2:22 p.m. 7:22 a.m. Farthest Cassini will venture into the D ring. Spacecraft will be shielded by its High Gain Antenna.
Downlink May 29 3:29 a.m. 8:29 p.m. (May 28) Estimated Earth Received Time (ERT) is 9:44 p.m. on May 28.
  • During this orbit, the spacecraft’s imaging cameras, Imaging Science Subsystem (ISS), takes images of the edge of the A ring, the F ring, and the space in between, to study ring structure and how ring particles interact in the region. Later in the orbit, the ISS does the same for the border region of Saturn’s B and C rings.
  • Cassini’s RADAR instrument performs the first of three parts to an experiment it has never tried before. Scanning inward from the outer edge of the A ring all the way through the innermost C ring, RADAR generates scans of the main rings at resolutions from 4 kilometers down to 100 meters per pixel.
  • During ring-plane crossing, the spacecraft is oriented such that its high-gain antenna (the big dish) faces forward (called “HGA to RAM”) to help shield the spacecraft from ring particles. This orbit’s ring-plane crossing is the highest Cassini ever gets in Saturn’s D ring.
  • Also during ring-plane crossing, in the six-minute period where impacts are considered most likely, the Radio and Plasma Wave Science instrument "listens" for the impacts of ring particles, which produce detectable plasma clouds when they strike the spacecraft. The antenna protrudes several meters beyond the protection of the high-gain antenna, allowing it to interact with ring particles while most of the spacecraft is shielded.
  • During this orbit, Cassini gets within 2,420 miles (3,900 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,370 miles (3,810 kilometers) of the inner edge of Saturn’s D ring.

COMPLETED: Orbit 277 - May 31 - June 7

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse May 31 8:04 p.m. 1:04 p.m.  
Ring Crossing #7 Jun 4 1:38 a.m. 6:38 p.m. (Jun 3) Second closest venture into the D ring. Spacecraft will be shielded by its High Gain Antenna.
Downlink Jun 4 2:10 p.m. 7:10 a.m. Estimated Earth Received Time (ERT) is 8:25 a.m. on June 4.
  • During this seventh Grand Finale orbit, while Cassini flies directly over the rings above Saturn's northern hemisphere, the Composite Infrared Spectrometer (CIRS) produces a high-resolution thermal scan across the main rings. By scanning the rings at an angle close to 90 degrees, the foreshortening that typically reduces the instrument's effective resolution on the rings is minimized. 
  • Cassini’s RADAR instrument performs the second of three parts to an experiment it has never tried before:  Scanning inward from the outer edge of the A ring all the way through the innermost C ring, RADAR generates scans of the main rings at resolutions from 4 kilometers down to 100 meters.
  • During this orbit’s ring-plane crossing, the spacecraft again is oriented such that its high-gain antenna (the big dish) faces forward (called HGA to RAM) to help shield the spacecraft from ring particles.
  • And again during ring-plane crossing, in the brief period in which impacts are considered most likely, the Radio and Plasma Wave Science (RPWS) instrument "listens" for the impacts of ring particles, which produce detectable plasma clouds when they strike the spacecraft. The antenna protrudes several meters beyond the protection of the high-gain antenna and so can still detect impacts.
  • During this orbit, Cassini gets within 2,420 miles (3,890 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,370 miles (3,820 kilometers) of the inner edge of Saturn’s D ring.

COMPLETED: Orbit 278 - June 7 - 13

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Jun 7 7:18 a.m. 12:18 a.m.  
Ring Crossing #8 Jun 10 12:49 p.m. 5:49 a.m.  
Downlink Jun 10 12:49 p.m. 5:49 a.m. Cassini will be communicating with Earth during the ring crossing. Estimated Earth Received Time (ERT) is 7:04 a.m. PDT on Jun 10.
  • During this orbit, Cassini’s Radio Science Subsystem (RSS) performs the fourth of six radio occultations of Saturn’s ring system and runs a gravity experiment to study Saturn's gravitational field in the highest possible detail. The experiment seeks to measure how spherical Saturn’s gravity field is, and to help scientists measure the mass of Saturn’s rings, a figure that is not precisely known.
  • During the radio experiments, Cassini’s Cosmic Dust Analyzer (CDA) scoops up and analyzes small ring particles to help determine the age of Saturn’s rings. Interplanetary meteoroids bombard Saturn’s main rings, depositing silicates, organics, and metals in the ring particles. The more of those contaminants the CDA finds, the older Saturn’s rings probably are.
  • Next Cassini’s Visible and Infrared Mapping Spectrometer (VIMS) maps Saturn’s southern hemisphere at some of the highest resolutions of the mission. The instrument looks for changes in winds, cloud structures and perhaps changes in atmospheric chemistry as the rate of atmospheric upwelling changes with seasons. 
  • During this orbit, Cassini gets within 2,120 miles (3,410 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,670 miles (4,300 kilometers) of the inner edge of Saturn’s D ring.

COMPLETED: Orbit 279 - June 13 - 20

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Jun 13 6:24 p.m. 11:24 a.m.  
Ring Crossing #9 Jun 16 11:52 p.m. 4:52 p.m.  
Downlink Jun 17 12:05 p.m. 5:05 a.m. Estimated Earth Received Time (ERT) is 6:20 a.m. PDT on Jun 17.
  • During this orbit, Cassini’s Ultraviolet Imaging Spectrograph (UVIS) observes Saturn’s northern aurora, attempting to capture the entire auroral oval over several observations. The Composite Infrared Spectrometer (CIRS) observes the aurora at the same time.
  • Cassini’s Ion and Neutral Mass Spectrometer (INMS) takes priority during ring-plane crossing, measuring the density and composition of neutral particles in that region to study the relationship between Saturn’s rings and the planet’s atmosphere. INMS also measures ions such as O2+ created on the surface of the rings and transported along field lines to other locations.
  • The Cosmic Dust Analyzer (CDA) samples ring particles around ring-plane crossing.
  • The spacecraft’s imaging cameras, the Imaging Science Subsystem (ISS), takes a special photo of the rings from the inside out around ring-plane crossing.
  • During this orbit, Cassini gets within 2,080 miles (3,350 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,710 miles (4,360 kilometers) of the inner edge of Saturn’s D ring.

IN PROGRESS: Orbit 280 - June 20 - 26

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Jun 20 5:26 a.m. 10:26 p.m. (Jun 19)  
Ring Crossing #10 Jun 23 10:54 a.m. 3:54 a.m.  
Downlink Jun 23 10:54 a.m. 3:54 a.m. Cassini will be communicating with Earth during the ring crossing. Estimated Earth Received Time (ERT) is 5:09 a.m. PDT on June 23.
  • During this orbit, Cassini’s Composite Infrared Spectrometer (CIRS) observes Saturn’s moon Dione to better understand the moon’s temperatures and to study the composition and structure of the moon’s surface material.
  • Cassini’s Radio Science Subsystem (RSS) performs another occultation of Saturn’s ring system and runs a gravity experiment to study Saturn's gravitational field in detail. The experiment seeks to measure how spherical Saturn’s gravity field is. Deviations from a spherical shape reveal how the density within Saturn varies with depth and how surface winds influence lower atmospheric depths. In addition, Cassini simultaneously feels the gravitational pull of the rings (the B-Ring, in particular). Scientists should be able to determine the rings' mass very accurately from the data collected on this pass.  The rings' mass helps scientists determine the age of the ring system.
  • During the radio experiments, Cassini’s Cosmic Dust Analyzer (CDA) scoops up and analyzes small ring particles to help determine the age of Saturn’s rings. Interplanetary meteoroids bombard Saturn’s main rings, depositing silicates, organics, and metals in the ring particles. The more of those contaminants the CDA finds, the older Saturn’s rings probably are.
  • The CIRS instrument also observes Saturn’s A ring to compare properties of ice in the rings and on Saturn’s icy moons.
  • During this orbit, Cassini gets within 2,110 miles (3,390 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,680 miles (4,320 kilometers) of the inner edge of Saturn’s D ring.

Orbit 281 - June 26 - July 3

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Jun 26 4:35 p.m. 9:35 a.m.  
Ring Crossing #11 Jun 29 10:10 p.m. 3:10 p.m. Cassini again ventures into the D ring. Spacecraft will be shielded by its High Gain Antenna.
Downlink Jun 30 9:55 a.m. 2:55 a.m. Estimated Earth Received Time (ERT) is 4:10 a.m. PDT on June 30.
  • During this orbit, Cassini’s Ultraviolet Imaging Spectrograph (UVIS) observes the edge of Saturn’s atmosphere, studying airglow, auroras and hydrocarbons — scientists need more information about Saturn’s hydrocarbon distribution to improve models of how sunlight affects the chemistry of the planet’s upper atmosphere.
  • The spacecraft’s Composite Infrared Spectrometer (CIRS) maps the temperature and composition of Saturn’s north polar vortex at the highest resolution of the mission so far.
  • Cassini’s Visible and Infrared Mapping Spectrometer (VIMS) captures a movie of Saturn’s south polar region. It is the closest and sharpest near-infrared movie to date of the intricate structure and complex movements of features in and around the south polar vortex.
  • During this orbit’s ring-plane crossing, the spacecraft is oriented such that its high-gain antenna (the big dish) faces forward (called HGA to RAM) to help shield the spacecraft from ring particles.
  • After ring-plane crossing, Cassini completes an engineering checkout of the spacecraft’s sun sensor assembly to be sure it wasn’t damaged when the high-gain antenna shielded the spacecraft during ring-plane crossing.
  • During this orbit, Cassini gets within 2,320 miles (3,720 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,480 miles (3,980 kilometers) of the inner edge of Saturn’s D ring.

Orbit 282 - July 3 - July 9

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Jul 3 3:54 a.m. 8:54 p.m. (July 2)  
Ring Crossing #12 Jul 6 9:31 a.m. 2:31 a.m. Cassini again ventures into the D ring. Spacecraft will be shielded by its High Gain Antenna.
Downlink Jul 7 5:44 a.m. 10:44 p.m.
(Jul 6)
Estimated Earth Received Time (ERT) is 11:59 p.m. PDT on July 6.
  • During this orbit, Cassini’s Ultraviolet Imaging Spectrograph (UVIS) stares at the star Kappa Canis Majoris, as parts of the C ring and A ring pass between the spacecraft and the star. The spacecraft’s Composite Infrared Spectrometer (CIRS) observes the occultation as well.
  • Cassini’s imaging cameras, the Imaging Science Subsystem (ISS), observes some of Saturn’s known ring propeller features, then targets the border region of the F ring and A ring to study ring dynamics there.
  • Cassini’s UVIS instrument also studies small-scale structures in the rings.
  • During this orbit’s ring-plane crossing, the spacecraft is oriented such that its high-gain antenna (the big dish) faces forward (called “HGA to RAM”) to help shield the spacecraft from ring particles.
  • Also during ring-plane crossing, in the brief period in which impacts are most likely, the Radio and Plasma Wave Science (RPWS) instrument "listens" for the impacts of ring particles, which produce detectable plasma clouds when they strike the spacecraft. The antenna protrudes several meters beyond the protection of the high-gain antenna and so still detects impacts.
  • During this orbit, Cassini gets within 2,320 miles (3,730 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,470 miles (3,980 kilometers) of the inner edge of Saturn’s D ring.

Orbit 283 - July 9 - July 16

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Jul 9 3:13 p.m. 8:13 a.m.  
Ring Crossing #13 Jul 12 8:44 p.m. 1:44 p.m.  
Downlink Jul 13 8:17 a.m. 1:17 p.m. Estimated Earth Received Time (ERT) is 2:33 a.m. PDT on July 13.
  • During this orbit, Cassini’s Composite Infrared Spectrometer (CIRS) observes the lit side of the middle A-ring to determine its composition and structure. The CIRS instrument then targets the point where Saturn’s shadow falls across the B-ring, studying how the ring’s temperature changes as it crosses into Saturn’s shadow.  These CIRS observations reveal details about the structure of the ring particles themselves, which are too small for Cassini's cameras to resolve.
  • Cassini’s imaging cameras, the Imaging Science Subsystem (ISS), observes some of Saturn’s known ring propeller features. The ISS also performs a high-resolution scan of Saturn’s C ring and inner B ring
  • With Cassini about 31,100 miles (50,000 kilometers) from Saturn's lower atmosphere, the Ion and Neutral Mass Spectrometer (INMS) samples the exosphere and ionosphere of Saturn and of the atmosphere-ionosphere of Saturn’s rings. On a later orbit (Orbit 288), the INMS will sample Saturn’s visible, much denser atmosphere for the first time.
  • During this orbit, Cassini gets within 1,780 miles (2,860 kilometers) of Saturn’s 1-bar level. Cassini also passes within 3,020 miles (4,850 kilometers) of the inner edge of Saturn’s D ring.

Orbit 284 - July 16 - July 22

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Jul 16 2:21 a.m. 7:21 p.m. (July 15)  
Ring Crossing #14 Jul 19 7:50 a.m. 12:50 a.m.  
Downlink Jul 19 7:50 a.m. 12:50 a.m. Cassini will be communicating with Earth during the ring crossing. Estimated Earth Received Time (ERT) is 2:06 a.m. PDT on July 19.
  • During this orbit, Cassini’s Radio Science Subsystem (RSS) performs its last science observations of the mission. The instrument conducts radio occultations of Saturn’s ring system and runs a gravity experiment to characterize Saturn's gravitational field with unprecedented detail. RSS determines Saturn's gravity by very precisely tracking the orbit of Cassini relative to the Earth as the spacecraft skims Saturn’s atmosphere. By measuring the Doppler shift in Cassini’s radio signal, scientists can learn how mass is distributed within Saturn. In addition, Cassini simultaneously feels the gravitational pull of the rings (the B-Ring, in particular) and determines their mass very accurately. The mass helps scientists determine the age of the ring system.
  • When Cassini is in the segment of this orbit in which it’s nearest to Saturn, the spacecraft rolls so that the Magnetometer (MAG) can collect unique measurements that will lead to a better understanding of Saturn’s magnetic field, the planet’s rotation rate, the size of the central core and other characteristics of Saturn.
  • Then the Visible and Infrared Mapping Spectrometer (VIMS) leads an observation of Saturn’s southern hemisphere at night.
  • During this orbit, Cassini gets within 1,740 miles (2,790 kilometers) of Saturn’s 1-bar level. Cassini also passes within 3,050 miles (4910 kilometers) of the inner edge of Saturn’s D ring.

Orbit 285 - July 22 - July 29

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Jul 22 1:27 p.m. 6:27 a.m.  
Ring Crossing #15 Jul 25 6:55 p.m. 11:55 a.m.  
Downlink Jul 26 6:10 a.m. 11:10 p.m. (July 25) Estimated Earth Received Time (ERT) is 12:27 a.m. PDT on July 19.

Orbit 286 - July 29 - August 4

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Jul 29 12:33 a.m. 5:33 p.m. (Jul 28)  
Ring Crossing #16 Aug 1 6:05 a.m. 11:05 p.m. (Jul 31)  
Downlink Aug 1 10:57 p.m. 3:57 p.m. Estimated Earth Received Time (ERT) is 5:14 p.m. PDT on August 1.
  • During this orbit, Cassini’s Ultraviolet Imaging Spectrograph (UVIS) makes a long observation of Saturn’s northern aurora at an unusually close range, producing some of the highest-resolution auroral images of the entire mission.
  • Cassini’s Visible and Infrared Mapping Spectrometer (VIMS) observes Saturn’s aurora during this orbit as well. This observation is the closest and highest-resolution auroral observation VIMS makes during Cassini’s entire mission.
  • The spacecraft’s Composite Infrared Spectrometer (CIRS) observes the south polar region of Saturn’s moon Enceladus during this orbit, studying winter temperatures on the moon’s surface. This is the instrument’s last opportunity of the mission to study the temperatures on Enceladus, to help researchers understand how they change over time.
  • During this orbit, Cassini gets within 1,820 miles (2,920 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,980 miles (4,790 kilometers) of the inner edge of Saturn’s D ring.

Orbit 287 - August 4 - August 10

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Aug 4 11:46 a.m. 4:46 a.m.  
Ring Crossing #17 Aug 7 5:19 p.m. 10:19 a.m.  
Downlink Aug 8 3:11 p.m. 8:11 a.m. Estimated Earth Received Time (ERT) is 9:29 a.m. PDT on August 8.
  • During this orbit Cassini’s Ultraviolet Imaging Spectrograph (UVIS) observes Saturn’s northern aurora, attempting to capture the entire auroral oval over several observations.
  • The spacecraft’s imaging cameras, the Imaging Science Subsystem (ISS), performs the first of two final observations of one of Saturn’s tiny, irregular moons, named Kiviuq, which completes about 80 percent of one rotation during Cassini’s observation. The observation is intended to improve models of the moon’s shape and other of Kiviuq’s characteristics.
  • The ISS instrument also targets one of Saturn’s ring propeller features, and also continues its campaign of observing Saturn’s moon Titan for two segments of time, each lasting several hours, to image the moon’s atmosphere and surface, in particular to watch Titan’s clouds form and change. The spacecraft’s Composite Infrared Spectrometer (CIRS) and Visible and Infrared Mapping Spectrometer (VIMS) observe Titan as well.
  • Also during this orbit, the spacecraft rolls to calibrate Cassini’s magnetometer (MAG).
  • During this orbit, Cassini gets within 1,830 miles (2,940 kilometers) of Saturn’s 1-bar level. Cassini also passes within 2,960 miles (4,760 kilometers) of the inner edge of Saturn’s D ring.

Orbit 288 - August 10 - August 17

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Aug 10 10:56 p.m. 3:56 p.m.  
Periapse Aug 14 4:22 a.m. 9:22 p.m. (Aug 13) First of the "Final Five" dips into Saturn's atmosphere.
Downlink Aug 15 12:26 a.m. 5:26 p.m. (Aug 14) Estimated Earth Received Time (ERT) is 6:45 p.m. PDT on August 14.
  • Cassini has just five orbits of Saturn remaining before the mission ends.
  • During this orbit, Cassini’s Composite Infrared Spectrometer (CIRS) observes the edge of Saturn’s atmosphere to determine different temperatures at different altitudes.
  • The spacecraft’s imaging cameras, the Imaging Science Subsystem (ISS), then observes mysterious features informally called “streaks” in Saturn’s C ring.
  • This is the first of five orbits in which Cassini’s elliptical orbit carries it so low that the spacecraft passes briefly through Saturn’s outermost atmosphere. Cassini’s reaction control thrusters are at the ready to correct the spacecraft’s orientation in case Saturn’s atmosphere pushes on the spacecraft hard enough to cause any rotation.
  • During the period in which the spacecraft is nearest Saturn, Cassini’s Ion and Neutral Mass Spectrometer (INMS) performs the first ever direct sampling of Saturn’s  atmosphere. The instrument measures densities of different species of molecular hydrogen, helium and a variety of ions in the immediate vicinity of the spacecraft.
  • Cassini’s RADAR instrument operates at the same time as INMS, studying Saturn’s atmosphere in a passive mode to study the small-scale structure and ammonia concentration of Saturn’s atmosphere.
  • During this orbit, Cassini gets within 1,070 miles (1,710 kilometers) of Saturn’s 1-bar level. Cassini also passes within 3,720 miles (5,990 kilometers) of the inner edge of Saturn’s D ring.

Orbit 289 - August 17 - August 23

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Aug 17 9:53 a.m. 2:53 a.m.  
Periapse Aug 20 3:23 p.m. 8:23 a.m. Second of the "Final Five" dips into Saturn's atmosphere.
Downlink Aug 21 3:10 a.m. 8:10 p.m. (Aug 20) Estimated Earth Received Time (ERT) is 9:30 p.m. PDT on August 20.
  • Cassini has less than a month before the mission ends, with just four orbits of Saturn remaining.
  • During this orbit, Cassini’s Ultraviolet Imaging Spectrograph (UVIS) observes Saturn’s northern aurora.
  • The spacecraft’s Composite Infrared Spectrometer (CIRS) observes temperatures in Saturn’s south polar vortex.
  • Cassini’s Visible and Infrared Mapping Spectrometer (VIMS) stares at Saturn’s south polar auroral region to produce a mosaic.
  • This is the second of five orbits in which Cassini’s elliptical orbit carries it so low that the spacecraft passes briefly through Saturn’s atmosphere. Cassini’s reaction control thrusters are at the ready to correct the spacecraft’s orientation in case Saturn’s atmosphere pushes on the spacecraft hard enough to cause any rotation.
  • During this orbit, Cassini gets within 1,030 miles (1,660 kilometers) of Saturn’s 1-bar level. Cassini also passes within 3,760 miles (6,040 kilometers) of the inner edge of Saturn’s D ring.

Orbit 290 - August 23 - August 30

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Aug 23 8:51 p.m. 1:51 p.m.  
Periapse Aug 27 2:20 a.m. 7:20 p.m. (Aug 26) Third and lowest of the "Final Five" dips into Saturn's atmosphere.
Downlink Aug 27 1:54 p.m. 6:54 a.m. Estimated Earth Received Time (ERT) is 8:14 a.m. PDT on August 27.
  • Cassini has just three orbits of Saturn remaining before the mission ends.
  • During this orbit Cassini’s Composite Infrared Spectrometer (CIRS) maps Saturn’s northern hemisphere to study temperatures in the upper troposphere and the Visible and Infrared Mapping Spectrometer (VIMS) creates a map of Saturn’s equatorial region. The CIRS instrument also performs its final Saturn limb observation of the mission.
  • The spacecraft uses its RADAR instrument in active mode to study Saturn’s atmosphere.
  • This is the third of five orbits in which Cassini’s elliptical orbit carries it so low that the spacecraft passes briefly through Saturn’s atmosphere. Cassini’s reaction control thrusters are at the ready to correct the spacecraft’s orientation in case Saturn’s atmosphere pushes on the spacecraft hard enough to cause any rotation. This is the deepest Cassini dips into Saturn’s atmosphere during the “Final Five” orbits.
  • During the period in which the spacecraft is nearest Saturn, Cassini’s Ion and Neutral Mass Spectrometer (INMS) performs its second session directly sampling Saturn’s upper atmosphere. The instrument measures densities of different species of molecular hydrogen, helium and a variety of ions in the immediate vicinity of the spacecraft.
  • During this orbit, Cassini gets within 1,020 miles (1,630 kilometers) of Saturn’s 1-bar level. Cassini also passes within 3,770 miles (6,070 kilometers) of the inner edge of Saturn’s D ring.

Orbit 291 - August 30 - September 5

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Aug 30 7:48 a.m. 12:48 a.m.  
Periapse Sep 2 1:17 p.m. 6:17 a.m. Fourth of the "Final Five" dips into Saturn's atmosphere.
Downlink Sep 3 4:38 a.m. 9:38 p.m. (Sep 2) Estimated Earth Received Time (ERT) is 10:59 p.m. PDT on September 2.
  • Cassini has just two orbits of Saturn remaining before the mission ends.
  • During this orbit, Cassini’s imaging cameras, the Imaging Science Subsystem (ISS), observes haze in Titan’s atmosphere, and the spacecraft’s Ultraviolet Imaging Spectrograph (UVIS) and Visible and Infrared Mapping Spectrometer (VIMS) instruments observe Saturn’s sunlit north polar auroral region.
  • The VIMS instrument and Cassini’s Composite Infrared Spectrometer (CIRS) work together to study Saturn’s atmosphere.
  • This is also the fourth of five orbits in which Cassini’s elliptical orbit carries it so low that the spacecraft passes briefly through Saturn’s atmosphere. Cassini’s reaction control thrusters are at the ready to correct the spacecraft’s orientation in case Saturn’s atmosphere pushes on the spacecraft hard enough to cause any rotation.
  • During the period in which the spacecraft is nearest Saturn, Cassini’s Ion and Neutral Mass Spectrometer (INMS) performs its third session directly sampling of Saturn’s upper atmosphere. The instrument measures densities of different species of molecular hydrogen, helium and a variety of ions in the immediate vicinity of the spacecraft.
  • During this orbit, Cassini gets within 1,020 miles (1,640 kilometers) of Saturn’s 1-bar level. Cassini also passes within 3,780 miles (6,080 kilometers) of the inner edge of Saturn’s D ring.

Orbit 292 - September 5 - 12

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Sep 5 6:47 p.m. 11:47 a.m.  
Periapse Sep 9 12:18 a.m. 5:18 p.m. (Sep 8) Last of the "Final Five" dips into Saturn's atmosphere.
Downlink Sep 9 1:07 p.m. 6:07 a.m. Estimated Earth Received Time (ERT) is 7:29 a.m. PDT on September 9.
  • This is Cassini’s final full orbit of Saturn before the mission ends.
  • During this orbit, Cassini’s Composite Infrared Spectrometer (CIRS) and Visible and Infrared Mapping Spectrometer (VIMS) instruments work together to determine the abundance of helium in Saturn’s atmosphere.
  • This is the fifth of five orbits in which Cassini’s elliptical orbit carries it so low that the spacecraft passes briefly through Saturn’s atmosphere. Cassini’s reaction control thrusters are at the ready to correct the spacecraft’s orientation in case Saturn’s atmosphere pushes on the spacecraft hard enough to cause any rotation.
  • During the period in which the spacecraft is nearest Saturn, Cassini’s Ion and Neutral Mass Spectrometer (INMS) performs its fourth session directly sampling Saturn’s upper atmosphere. The instrument measures densities of different species of molecular hydrogen, helium and a variety of ions in the immediate vicinity of the spacecraft.
  • The spacecraft’s RADAR and Imaging Science Subsystem (ISS) instruments also operate during the INMS observation, with RADAR continuing its study of ammonia in Saturn’s atmosphere and the ISS instrument capturing an iconic image of the rings seen looking outward from Saturn.
  • At the end of this orbit, Cassini makes a distant flyby of the Mercury-size moon Titan, whose gravity alters the spacecraft’s trajectory one final time. This gravitational nudge, which the team calls “the goodbye kiss,” ensures that the spacecraft is disposed of in a controlled manner. Instead of passing safely into and out of Saturn’s outermost atmosphere on the next orbit, Cassini will instead dip so deeply into the atmosphere that the spacecraft will burn up like a meteor.
  • During this orbit, Cassini gets within 1,050 miles (1,680 kilometers) of Saturn’s 1-bar level. Cassini also passes within 3,800 miles (6,120 kilometers) of the inner edge of Saturn’s D ring.

Orbit 293 - The Grand Finale - September 12 - 15

Event Date Spacecraft Time (UTC) Local Time (PDT) Notes
Apoapse Sep 12 5:37 a.m. 10:37 p.m. (Sep 11) The start of Cassini's final plunge into Saturn. The spacecraft will downlink to the Deep Space Network at the end of the day.
Atmospheric Entry Sep 15 10:44 a.m. 3:44 a.m. Thrusters will maintain attitude control for about a minute. Earth Recieved Time (ERT) of the final data transmission is about 5:07 a.m. PDT.
Loss of Signal Sep 15 10:45 a.m. 3:45 a.m. Estimated Earth Received Time (ERT) for the end of mission is  5:08 a.m. PDT on September 15.
  • During this partial orbit, when Cassini is three and half hours from its expected end of mission, data from the spacecraft’s Composite Infrared Spectrometer (CIRS), Ultraviolet Imaging Spectrograph (UVIS), and magnetospheric and plasma science instruments are transmitted to Earth in nearly real time, just seconds after each observation is made. Cassini usually holds onto those data for hours or days before turning its high-gain antenna toward Earth to transmit them.
  • Unlike the preceding orbits, where the Cassini’s lowest altitudes were chosen to avoid tumbling, the spacecraft trajectory on this orbit intentionally continues all the way into Saturn.
  • Cassini continues transmitting as long as possible until the force of Saturn’s atmosphere overpowers the spacecraft’s thrusters and Cassini can no longer point its antenna precisely enough to maintain contact with Earth.
  • When the spacecraft’s signal is lost, the Cassini mission comes to an end.

Go to the Grand Finale Overview page.

For additional details about Cassini's recent activities, see Saturn Tour Dates for 2016 & 2017

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