After losing communication with the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft in late February, NASA scientists responsible for the mission began an investigation to understand why the instruments were automatically placed in safe mode. A little more than three months later, the agency announced that the spacecraft has returned to normal scientific operations.
The team was able to successfully diagnose the problem and complete the development of a system that should allow for the continuity of mission operations over the next decade.
"This was a critical challenge to the mission, but thanks to the work of our spacecraft and operations team, MAVEN will continue to produce important science and operate in a phase of surface assets through the end of the decade," said Shannon Curry, principal maven researcher at the University of California. "I couldn't be more proud of our team."
Launched in November 2013, the MAVEN spacecraft entered orbit around Mars in September 2014, to explore the planet's ionosphere and interactions with the Sun and solar wind to understand the loss of the Martian atmosphere into space.
This can give scientists an insight into the history of Mars' atmosphere and climate, liquid water, and planetary habitability. MAVEN's primary mission was one year long. Recently, the spacecraft received approval for its fifth extended mission.
How the MAVEN probe stopped working on Mars
On February 22, the team lost contact with the spacecraft after it performed a routine imu-1 scheduled power cycle. The Inertial Measurement Units (IMUs) are used to determine the probe's attitude in space by measuring its rotation rate. MAVEN has two identical IMUs on board: the IMU-1 is the primary unit, and the IMU-2 is the backup unit.
Once contact with the spacecraft was restored, engineering telemetry showed that the equipment's IMU-1 was unable to determine its attitude. In response, the spacecraft performed a reboot of the computer but was not yet able to determine its orientation.
As a last resort, MAVEN switched to the backup computer, which allowed it to receive accurate readings of the IMU-2. The spacecraft was automatically placed in safe mode, disrupting all planned activities, including scientific and relay operations.
According to Phys, the team had already been working on developing an all-stellar mode —a system for navigating stars without IMUs—to be implemented in October 2022 because IMU-1 had already shown anomalies and the IMU-2 was nearing its useful life.
"This was a situation that no one initially anticipated, but the spacecraft performed as designed," said Micheal Haggard, head of the MAVEN team at Lockheed Martin. "When we ended up on the backup computer, the spacecraft was trying to solve the problem with the IMU-1 for about 78 minutes. We ended up on IMU-2, and the pressure started to get all-stellar mode ready as soon as possible."
So Lockheed Martin's spacecraft team worked hard to accelerate software development, as the expected lifespan of the IMU-2 would not last until October (the initial deadline given for completion of the system).
On April 19, the spacecraft team completed development and provided the software for MAVEN to operate in all-stellar mode. As soon as the code was activated, the IMU-2 was turned off, preserving its remaining life for future needs.
With the new system on, the technicians on Earth fed the instruments and set them up for scientific operation. All instruments were healthy and successfully resumed observations.