Whichever IMU the spacecraft is using at any given time is responsible for keeping MAVEN in the right attitude, or orientation in space. The spacecraft carries two of what engineers call inertial measurement units, or IMUs: one primary version, dubbed IMU-1, and an identical backup called IMU-2. However, MAVEN has spent more than eight years in space, far longer than it was initially designed for, and one particular part is giving the team trouble. It’s not a mission that NASA wants to end, and indeed, at the end of the review process that culminated in the grueling presentation, the agency authorized the mission to continue work for three more years. Since then, the spacecraft has not only studied the Martian atmosphere, as its name promises, but has also acted as a key relay station for communications between NASA and its Martian landers and rovers, which cannot directly signal Earth. MAVEN, more formally known as Mars Atmosphere and Volatile Evolution, arrived in orbit around the Red Planet in 2014. “It was like getting the wind knocked out of you.
“The safe mode event was - catastrophic is too strong, but I mean, we did get close to losing the spacecraft,” Curry said, calling the incident “incredibly serious” and “scary.” And when the team wanted to be celebrating the end of the six-month mission extension campaign, the timing stung.
