NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft is the first Mars orbiter designed specifically 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 and goes into safe mode
After three months in safe mode, NASA’s MAVEN spacecraft has finally returned to normal science and relief operations. The problem began on February 22, 2022, when contact with the spacecraft was lost. After re-establishing contact, its main inertial unit of measurement, IMU-1, a critical system for navigation, did not work and the team had to change the spacecraft to its backup, IMU-2. However, this unit was also nearing the end of its useful life. The spacecraft was put into safe mode, while engineers rushed to complete a star mode in which the spacecraft could navigate using stars instead of IMUs. With an existential threat approaching, the team took a step back and completed the necessary new software 5 months ahead of schedule.
NASA’s Mars Atmosphere and Volatile EvolutioN, or MAVEN, mission returned to normal science and relief operations on May 28, 2022, after recovering from a prolonged event in safe mode. The spacecraft encountered problems in February with its inertial units of measurement (IMU). The mission team successfully diagnosed the problem with these navigation instruments and developed a system for the spacecraft to navigate the stars, which should allow the operations of the MAVEN mission to continue for the next decade.
“The team really faced an existential threat.” – Rich Burns, MAVEN project manager
“This was a critical challenge for the mission, but thanks to the work of our spacecraft and operations team, MAVEN will continue to produce important science and function as a relay for surface assets until the end of the decade.” said Shannon Curry, head of MAVEN. principal investigator at the University of California, Berkeley. “I couldn’t be more proud of our team.”
MAVEN was launched in November 2013 and entered orbit around Mars in September 2014. The goal of the mission is to explore the planet’s upper atmosphere, ionosphere, and interactions with the Sun and the solar wind by explore the loss of the Martian atmosphere in space. Understanding atmospheric loss provides scientists with an insight into the history of Mars’ atmosphere and climate, liquid water, and planetary habitability. MAVEN’s main mission lasted a year. It has since far surpassed it and has recently been approved for its fifth expanded mission.
This illustration shows NASA’s MAVEN spacecraft. Credit: NASA / Goddard
Event in safe mode
On Tuesday, February 22, 2022, the team lost contact with the spacecraft after performing a routine scheduled launch cycle of the IMU-1. IMUs are used to determine the attitude of the spacecraft into space by measuring its rotational speed. MAVEN has two identical IMUs on board: IMU-1 is the main unit and IMU-2 is the security unit. Once contact with the spacecraft was restored, engineering telemetry showed that the spacecraft could not determine its attitude from any of the IMUs. In response, the spacecraft restarted the computer but was unable to determine its orientation. As a last resort, the spacecraft switched to the backup computer, allowing MAVEN to obtain accurate IMU-2 readings. The spacecraft entered “safe mode”, where it ceased all planned activities, including science and relay operations, and waited for further instructions from the ground.
The team had already been working to develop a star mode, a system for navigating stars without an IMU, which would be implemented in October 2022 because IMU-1 had previously shown anomalies and IMU-2 was approaching end of its useful life. Development and change to star mode is standard practice when IMUs degrade into aged orbits.
“This was a situation that no one initially anticipated, but the spacecraft worked the way it was designed,” said Micheal Haggard, team leader for the Lockheed Martin MAVEN spacecraft team in Littleton, Colorado. “When we finished the backup computer, the spacecraft had been trying to fix the problem with the IMU-1 for about 78 minutes. We finished the IMU-2 and the pressure was pressed to prepare the stellar as soon as possible.
This image shows the concept of an artist on NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission. Credit: NASA’s Goddard Space Flight Center
A race against time
In the months that followed, Lockheed Martin’s spacecraft team worked to accelerate software development to enable all-star mode, as the expected lifespan of the IMU-2 would not last until October. On April 19, five months ahead of schedule, the spacecraft team completed development and linked the software patch to MAVEN. As soon as the code was connected, the IMU-2 shut down, preserving its remaining life for the future needs of spacecraft. Following the uplink, a series of tests were performed to verify the functionality of the all-star mode, as the code had not been previously tested in flight.
“The team really faced an existential threat,” said Rich Burns, the MAVEN project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “When we recognized in the fall that IMU-2 was degrading, we learned that we should shorten the stellar mode calendar. The spacecraft team took up the challenge, working under intense pressure. after the anomaly “.
Once the star mode was connected up, the spacecraft and scientific equipment turned on the instruments and set them up for scientific operation. All instruments were healthy and resumed observations successfully; however, the spacecraft was limited to aiming at Earth until all-star mode tests were 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 an impact of coronal mass ejection on Mars less than two days after the instruments were turned on.
This image shows the concept of an artist on NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission. Credit: Lockheed Martin
Forward to science and relief
MAVEN returned to nominal science and relay operations on Saturday, May 28, 2022, after successfully moving to full star navigation.
The MAVEN spacecraft continues to operate successfully using star mode. There are usually certain times each year that IMUs should be used, so the team will need to continue to find innovative ways to control the orientation of the spacecraft. This will ensure that MAVEN can continue to operate during its extended mission life, allowing the orbit to continue to observe during the most extreme conditions of the Martian atmosphere that the mission has encountered so far.
The MAVEN 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 the mission’s operations. NASA’s Jet Propulsion Laboratory in Pasadena, California, provides support for navigation and the deep space network. The Atmospheric and Space Physics Laboratory at the University of Colorado Boulder is responsible for managing scientific operations and public outreach and communication.