The Mars Atmosphere and Volatile Evolution (MAVEN) orbiter went behind Mars on December 4, the last time it sent telemetry data to Earth. MAVEN re-emerged on December 6 but did not send any signal to the Deep Space Network, meaning it had lost contact with NASA.
“Telemetry from MAVEN showed all subsystems working normally before it orbited behind the Red Planet,” NASA reported on December 9.
According to the agency, all attempts to reestablish contact have been unsuccessful as of December 15. Scientists did, however, recover a fragment of tracking data from December 6. Efforts continue as of now.
Analysis suggests MAVEN was rotating in an unexpected manner when it re-emerged. The frequency of the tracking signal suggests that MAVEN’s orbital trajectory may have changed.
MAVEN is one of three active orbiters around Mars, including the Mars Reconnaissance Orbiter, launched in 2005, and Mars Odyssey, launched in 2001.
It was launched in November 2013 and entered the Martian orbit by September 2014. Since then, MAVEN has helped scientists understand the red planet’s upper atmosphere, ionosphere, and its interactions with the Sun and solar wind to explore the loss of the Martian atmosphere to space.
The spacecraft also serves as a communications relay station for rovers on the Martian surface.
This isn’t the first time the spacecraft has experienced technical issues in orbit. On February 22, 2022, NASA temporarily lost contact with MAVEN after the spacecraft performed a routine, scheduled power cycle of its primary inertia measurement unit (IMU-1).
IMUs are used to determine a spacecraft’s orientation in space by measuring its rate of rotation. MAVEN carries two identical units, with IMU-1 serving as the primary system and IMU-2 as the backup.
After contact was restored, engineering telemetry showed the spacecraft could not determine its attitude using either IMU. MAVEN initiated a computer reboot, but the issue persisted.
As a last resort, the spacecraft switched to its backup computer in order to obtain accurate readings from IMU-2. MAVEN then entered safe mode, halting all planned science and relay operations while awaiting instructions from Earth.
NASA had become aware of potential failures in MAVEN’s IMUs in late 2021. The mission had already transitioned from the primary IMU to the backup unit in 2017, and engineers later observed signs of degradation in the backup system as well. By February 2022, both IMUs appeared unable to reliably perform their measurements.
To fix the issue, NASA engineers reprogrammed MAVEN to operate in an “all-stellar” mode, using star positions to determine the spacecraft’s orientation and maintain its orbit without relying on the IMUs.
This configuration was implemented in April 2022 and completed by May 28, 2022. During the transition, MAVEN was unavailable for scientific observations or for relaying communications from the Curiosity and Perseverance rovers and the InSight lander, with reduced communications handled by other Mars orbiters.