The Cassini spacecraft's journey ends Friday and the international astronomical community is profoundly moved. But both Voyager spacecraft continue their explorations.
This July 23, 2008 image made available by NASA shows the planet Saturn, as seen from the Cassini spacecraft. After a 20-year voyage, Cassini is poised to dive into Saturn on Friday, Sept. 15, 2016.
(NASA/JPL/Space Science Institute via AP)
NASA/JPL/Space Science Institute via AP
This Nov. 13, 2015 composite image made available by NASA shows an infrared view of Saturn’s moon, Titan, as seen by the Cassini spacecraft. The near-infrared wavelengths in this image allow the cameras to penetrate the haze and reveal the moon’s surface.
(NASA/JPL/ESA/Italian Space Agency via AP)
NASA/JPL/ESA/Italian Space Agency via AP
This Dec. 3, 2015 image made available by NASA shows three of Saturn’s moons – Tethys, above, Enceladus, second left, and Mimas, seen from the Cassini spacecraft.
(NASA/JPL-Caltech/Space Science Institute via AP)
NASA/JPL-Caltech/Space Science Institute via AP
This Aug. 12, 2009 composite image made available by NASA shows Saturn in equinox seen by the approaching Cassini spacecraft. Saturn’s equinox occurs only once in about 15 Earth years.
(NASA/JPL/Space Science Institute via AP)
NASA/JPL/Space Science Institute via AP
This Sept. 6, 2015 image made available by NASA shows bright-and-dark bands in the atmosphere of Saturn, as seen from the Cassini spacecraft. This image was taken in wavelengths of light that are absorbed by methane. Dark areas are regions where light travels deeper into the atmosphere, passing through more methane. The moon Dione is at right. At bottom are shadows of the planet’s rings.
(NASA/JPL-Caltech/Space Science Institute via AP)
NASA/JPL-Caltech/Space Science Institute via AP
This July 19, 2013 image made available by NASA shows Saturn’s rings and planet Earth, center right, as seen from the Cassini spacecraft.
(NASA/JPL-Caltech/Space Science Institute via AP)
NASA/JPL-Caltech/Space Science Institute via AP
This 2007 image made available by NASA shows a hydrocarbon sea named Ligeia Mare on Saturn’s moon Titan, as seen by the Cassini spacecraft. Slight changes observed over several passes indicates that Titan’s seas are not stagnant, but rather, dynamic environments. Ligeia is Titan’s second-largest liquid hydrocarbon sea, and has a total area of about 50,000 square miles (130,000 square kilometers), making it 50 percent larger than Lake Superior on Earth.
(NASA/JPL-Caltech/ASI/Cornell via AP)
NASA/JPL-Caltech/ASI/Cornell via AP
FILE – In this Wednesday, March 26, 1997 file photo, a technician checks the heatshield of the space probe Huygens in the cleanroom of Dornier Satellitensysteme GmbH in Ottobrunn, Germany, near Munich. The probe will be carried by NASA’s Cassini orbiter and is designed to explore Saturn’s moon Titan.
(AP Photo/Uwe Lein)
AP Photo/Uwe Lein
In this Oct. 31, 1996 photo made available by NASA, the newly assembled Cassini Saturn probe undergoes vibration and thermal testing at the Jet Propulsion Laboratory facilities in Pasadena, Calif. It was subjected to weeks of “shake and bake” tests that imitate the forces and extreme temperatures the spacecraft would experience during launch and spaceflight.
(NASA via AP)
NASA via AP
FILE – In this Aug. 4, 1977 photo provided by NASA, the “Sounds of Earth” record is mounted on the Voyager 2 spacecraft in the Safe-1 Building at the Kennedy Space Center, Fla., prior to encapsulation in the protective shroud. Sunday, Aug. 20, 2017 marks the 40th anniversary of NASA’s launch of Voyager 2, now almost 11 billion miles distant.
(AP Photo/NASA)
AP Photo/NASA
FILE – This undated image provided by NASA shows the cover of the 12-inch gold-plated copper disk that both Voyager spacecraft carry. The phonograph record contains sounds and images selected to portray the diversity of life and culture on Earth.
(AP Photo/NASA)
AP Photo/NASA
FILE – In this Saturday, Aug. 20, 1977 file photo, the Voyager 2 spacecraft, atop a Titan Centaur rocket, is launched from Cape Canaveral, Fla. The spacecraft will explore the outer planets Saturn and Jupiter.
(AP Photo)
AP Photo
FILE – In this Aug. 26, 1981 file photo, Voyager 2 mission director Dick Laeser looks at a platform on the end of a boom on a mock-up of the Voyager spacecraft during a news briefing at the Jet Propulsion Lab in Pasadena, Calif. Sunday, Aug. 20, 2017 marks the 40th anniversary of NASA’s launch of Voyager 2, now almost 11 billion miles distant.
(AP Photo/Lennox McLendon)
AP Photo/Lennox McLendon
This undated photo provided by NASA’s Jet Propulsion Lab showing the Voyager spacecraft in Passadena, Calif. On right side of the craft is girder-like boom which holds science project equipment and the imaging camera. Sunday, Aug. 20, 2017 marks the 40th anniversary of NASA’s launch of Voyager 2, now almost 11 billion miles distant.
(JPL/NASA via AP)
JPL/NASA via AP
This illustration provided by NASA/JPL/Mark Showalter, SETI Institute depicts Pluto and its five moons from a perspective looking away from the sun. It is adapted from a classic Voyager I montage of Jupiterís Galilean moons, and is intended to highlight similarities between the Pluto and Jupiter systems when adjusted for size. Approaching the system, the outermost moon is Hydra, seen in the bottom left corner. The other moons are roughly scaled to the sizes they would appear from this perspective, although they are all enlarged relative to the planet.
(NASA/JPL/Mark Showalter, SETI Institute via AP)
WASHINGTON — The Cassini spacecraft’s impending end has much of the global astronomical community profoundly moved on Thursday. Tweets fill the timeline about the intrepid explorer that has been in space almost 20 years and in orbit around Saturn and its moons for 13 years.
I’m quite sure there are a few wet eyes behind those tweets for what NASA is calling “The Grand Finale.”
At approximately 7:55 a.m. Friday, NASA expects to lose contact with Cassini as the spacecraft hits the upper atmosphere of the ringed planet at a blistering 70,000 miles per hour. An explorer to the very end, Cassini will be livestreaming its last moments and gathering data with eight of its 12 science instruments until the thrusters cannot overcome the aerodynamic forces. Cassini will tumble, break apart and finally be consumed like a shooting star in the atmosphere of Saturn.
It will take 83 minutes for Cassini’s final data transmission to reach Earth, traveling at the speed of light, 186,000 miles per second. Almost a billion miles away, Saturn and its moons will once again be solitary in their orbit around the sun. Gone will be the amazing spacecraft that took thousands of photographs, collected terabytes of data, sent the European Space Agency’s Huygens lander to Titan and discovered a large global ocean under the thick ice at Enceladus.
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“The final set of views from Cassini’s imaging cameras is scheduled to be taken and transmitted to Earth on Thursday, Sept. 14,” according to NASA. “If all goes as planned, images will be posted to the Cassini mission website beginning around 11 p.m. EDT (8 p.m. PDT). The unprocessed images will be available at: https://saturn.jpl.nasa.gov/galleries/raw-images.”
To watch live mission commentary and video from JPL Mission Control, visit NASA TV or NASA’s website from 7 to 8:30 a.m. Friday. The post-mission news briefing is scheduled for 9:30 a.m.
NASA TV:
The free e-book “The Saturn System Through the Eyes of Cassini,” which NASA says showcases “compelling images and key science discoveries from the mission,” can be downloaded here.
Bright Saturn is in the southwest sky after dark. Tonight, look at Saturn and say farewell to Cassini. And when “The Grand Finale” for Cassini is finally over, take some comfort — as will I — in knowing that the atoms that were Cassini are now part of Saturn.
Voyagers 1 & 2
Two NASA spacecraft — Voyager 1 and Voyager 2 — made world headlines recently by celebrating their 40th anniversaries in space. Voyager 1 is about 13 billion miles from Earth and is cruising interstellar space, while the distance of Voyager 2 is 11 billion miles. Both are healthy and continue to send data back to Earth.
They will go silent years from now when their radioactive fuel supply is spent.
These twins opened up the outer solar system of gas giant planets — Jupiter, Saturn, Uranus and Neptune — as we had never seen them before. With their respective flybys, the Voyagers transformed these giants from what could be obtained through telescopes to up close and mesmerizing personal views. The science obtained filled volumes, and the photographs we saw transformed these worlds into actual worlds we had visited.
The Voyagers have become cultural icons due in part to their longevity, discoveries and perhaps most importantly of all, “the Golden Record” that each of them carries. The late Dr. Carl Sagan was the primary mover in getting these artifacts of Earth and humanity placed on the Voyagers. He also convinced NASA to take the first-ever portrait of the solar system, which included Earth.
The famous “Pale Blue Dot” photograph became the subject of a wonderful book by Sagan. Much of what he wrote is even more meaningful today. I highly recommend reading it, as well as Sagan’s other books.
The Voyagers may very possibly outlive humanity as they could roam the Milky Way galaxy for hundreds of millions of years. Unless they collide with something in space, they will be a lasting testament to a species who reached for the stars — and put out a Golden Record to say, “Hello.”
