NASA’s Mars Space and Volatile Evolution Spacecraft (MAVEN) is the first Mars orbiter specifically designed to study the planet’s upper atmosphere and its interaction with the solar wind. Credit: NASA’s Goddard Space Flight Center
NASA’s MAVEN spacecraft resumes science and operations, leaves safe mode
After three months in safe mode, NASA’s MAVEN spacecraft has finally returned to normal scientific and relay operations. The problem began on February 22, 2022, when contact with the spacecraft was lost. After reconnection, its main inertial measurement unit, IMU-1, a navigation-critical system, was down and the team had to transfer the spacecraft to its backup IMU-2. But this device was also near the end of his life. The spacecraft was put into safe mode as engineers raced to complete an all-star mode in which the spacecraft could move using stars instead of IMU. With the looming existential threat, the team stepped up and completed the new software needed 5 months ahead of schedule.
NASA’s Mars Atmosphere and Volatile EvolutionN, or MAVEN, mission returned to normal scientific and relay operations on May 28, 2022, after recovering from an extended event in safe mode. The spacecraft encountered problems in February with its inertial units (IMU). The mission team successfully diagnosed the problem with these navigation tools and developed a system for the spacecraft to navigate the stars, which should allow MAVEN to continue its mission over the next decade.
“The team really focused on the existential threat. – Rich Burns, MAVEN project manager
“This was a critical challenge for the mission, but thanks to the work of our spacecraft and operational team, MAVEN will continue to produce important science and act as a relay for surface assets until the end of the decade,” said Shannon Curry, MAVEN. principal investigator at the University of California, Berkeley. “I can’t be proud of our team.
MAVEN launched in November 2013 and entered orbit around Mars in September 2014. The mission aims to explore the planet’s upper atmosphere, ionosphere and interactions with the Sun and solar wind to investigate the loss of the Martian atmosphere in space. Understanding atmospheric losses gives scientists an idea of the history of the atmosphere and climate of Mars, liquid water and planetary habitat. MAVEN’s main mission was one year. He has since gone far beyond that and was recently approved for his fifth extended mission.
This illustration shows NASA’s MAVEN spacecraft. Credit: NASA / Goddard
Safe mode event
On Tuesday, February 22, 2022, the team lost contact with the spacecraft after performing a routine planned IMU-1 power cycle. IMUs are used to determine the spacecraft’s position in space by measuring its speed of rotation. MAVEN has two identical IMUs on board: the IMU-1 is the main unit and the IMU-2 is the backup. After contact with the spacecraft was restored, telemetry engineering showed that the spacecraft was unable to determine its relationship from any IMU. In response, the spacecraft restarted the computer, but could not yet determine its orientation. As a last resort, the spacecraft was replaced with a backup computer, which allowed MAVEN to obtain accurate readings from the IMU-2. The spacecraft entered “safe mode”, where it suspended all planned activities, including scientific and relay operations, and waited for further instructions from the ground.
The team has already worked to develop an all-star mode – a star-free navigation system without IMU – to be implemented in October 2022, as IMU-1 has previously shown anomalies and IMU-2 is nearing the end of its life. . Developing and switching to all-star mode is standard practice when IMUs decompose in aging orbiters.
“It was a situation no one expected at first, but the spacecraft performed as it was designed,” said Michael Haggard, head of the Lockheed Martin MAVEN spacecraft team in Littleton, Colorado. “By the time we got to the backup computer, the spacecraft had been trying to solve the IMU-1 problem for about 78 minutes. We ended up on IMU-2 and were pressed to prepare for star mode as quickly as possible.
This image shows the artist’s concept of NASA’s Mars Atmosphere and Volatile EvolutionN (MAVEN) mission. Credit: NASA’s Goddard Space Flight Center
Race against time
In the coming months, the Lockheed Martin spacecraft team is working to accelerate software development to allow all-star mode, as the projected life of IMU-2 will not last until October. On April 19, five months before the schedule, the spacecraft team completed development and transferred the software patch to MAVEN. As soon as the code was linked up, the IMU-2 was turned off, saving the rest of its life for future use by the spacecraft. Following the uplink, a series of tests were performed to test the functionality of all stellar modes, as the code had not been tested in flight before.
“The team has really stepped up to an existential threat,” said Rich Burns, MAVEN project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “When we learned in the fall that IMU-2 was degrading, we knew we would have to cut the schedule for all star modes. The spacecraft team tackled the challenge by working under intense pressure after the anomaly. “
After the all-star mode was connected upwards, the spacecraft and the scientific teams turned on the instruments and configured them for scientific work. All instruments were robust and observations were successfully resumed; however, the spacecraft was limited to heading toward Earth until all-star testing was completed, so the instruments were not oriented as they normally would be during scientific operations. However, some limited science was still possible and MAVEN even observed the impact of coronal mass ejection on Mars less than two days after the instruments were turned on.
This image shows the artist’s concept of NASA’s Mars Atmosphere and Volatile EvolutionN (MAVEN) mission. Credit: Lockheed Martin
Forward to science and relay
MAVEN returned to nominal science and relay operations on Saturday, May 28, 2022, after a successful transition to full-star navigation.
The MAVEN spacecraft continues to operate successfully, using all-star mode. There are usually certain times each year when IMUs need to be used, so the team will need to continue to find innovative ways to control the spacecraft’s orientation. This will ensure that MAVEN can continue to operate during the extended life of the mission, which will allow the orbiter to continue to make observations during the most extreme conditions in the Mars atmosphere that the mission has encountered so far.
MAVEN’s principal investigator is based at the University of California, Berkeley, while NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the MAVEN mission. Lockheed Martin Space built the spacecraft and is responsible for mission operations. NASA’s Jet Propulsion Laboratory in Pasadena, California, provides navigation and Deep Space Network support. The Laboratory of Atmospheric and Space Physics at the University of Colorado Boulder is responsible for managing scientific operations and dissemination and communication.
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