Back in early December, the 10th, we learned that NASA's MAVEN satellite that had been in orbit around Mars for 11 years had suddenly gone quiet. The satellite went behind Mars from Earth's viewpoint, an occultation, but ground teams didn’t hear from the spacecraft when it was supposed to regain contact with Earth. In the 10 years of the mission up to that point they had gone through other occultations without issue.
Ground teams last heard from the Mars Atmosphere and Volatile EvolutioN, or MAVEN, spacecraft on Saturday, December 6. “Telemetry from MAVEN had showed all subsystems working normally before it orbited behind the red planet,” NASA said in a short statement. “After the spacecraft emerged from behind Mars, NASA’s Deep Space Network did not observe a signal.”
As always, the mission had contingency plans that included bad scenarios like this one and various plans to try to contact MAVEN that were invoked. They listened for faint signals and uplinked commands in the blind but never heard the satellite again. Hopes of saving the mission faded over time and on Wednesday they announced they were saying good-bye.
“NASA has ceased efforts to search for the MAVEN spacecraft and are beginning activities to decommission the mission,” said Mike Moreau, MAVEN’s project manager at NASA’s Goddard Space Flight Center in Maryland.
It will take some time to decide how MAVEN failed. While not based on a constant download of information in real time, MAVEN was working properly before passing behind Mars and the next time they should have heard it, there was nothing.
“One of the bits of that we were able to confirm is an inertial rate measurement that told us the spacecraft was spinning at about 2.7 revolutions per minute,” Moreau said. “We also confirmed that that was consistent with a Doppler signature that we saw in the data. That’s faster than the spacecraft is expected to rotate, and that indicates a problem that the spacecraft probably couldn’t recover from.”
Without the ability to point its solar arrays toward the Sun, the tumbling spacecraft likely drained its batteries within hours.
“That was one of the data points that helped us understand that the spacecraft probably reached a power state that was not supportable to continue operations,” Moreau said. “Those are the facts that we know. The anomaly review board is still looking at the root cause of what actually initiated the failure.”
MAVEN orbits Mars in an eccentric elliptical orbit with a low point as close as 110 miles and high point as far as 2,500 miles from the planet’s surface. It's expected to remain in this orbit for the next foreseeable 50 to 100 years before the thin atmosphere of Mars eventually causes it to come out of orbit and smash into the planet.
Artist’s illustration of the MAVEN spacecraft in its elliptical orbit around
Mars. Not even remotely to scale. Credit: NASA/University of Colorado/LASP
For most of its time at Mars, MAVEN served as a radio relay for small robots exploring Mars, like the rovers and even landers. This allowed NASA to return significantly more data and imagery from rovers like Perseverance and Curiosity than would be possible through a direct-to-Earth radio connection. NASA has four other satellites that could take the place of MAVEN but three of the four are older than MAVEN was.
“Over the life of the mission, MAVEN supported more than 8 percent of all of our relay sessions planned by our rovers and landers, but it accounted for nearly 18 percent of all of the data returned, illustrating its usefulness when returning large data volumes,” said Tiffany Morgan, director of NASA’s Mars Exploration Program.
Perhaps the better way to close this is to pass along two big quotes from Wednesday's meeting.
Shannon Curry, MAVEN's principal investigator, described the probe as the "Best. Mars. Mission. Ever." during Wednesday's call. Mike Moreau, the MAVEN project manager, praised the team and said they, "really experienced the loss of a loved one with the end of the mission here."
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