The space environment around Mars is mostly clean of space junk but even there, space craft risk collisions. And sometimes the collision is with the Red Planet’s biggest moon, Phobos.
This week, MAVEN – NASA’s Mars Atmosphere and Volatile EvolutioN satellite – carried out a rare unscheduled maneuver to avoid a collision with Phobos in a few days time. The spacecraft performed a short motor burn to increase its velocity of 0.4 meters per second (0.89 miles per hour). This modest change was enough to put several hundred kilometers between the probe and the moon when their orbits will cross next week.
MAVEN is tasked with studying the Martian atmosphere and how the Red Planet lost most of it. To achieve this goal is in a wide elliptical orbit, which takes the craft as close as 150 kilometers and as far as 6,200 (93 – 3.900 miles) from the surface of Mars.
This wide orbit often crosses path with other orbiters as well as Phobos, so astronomers from NASA’s Jet Propulsion Laboratory need to keep an eye out for potential encounters and make small adjustments when necessary. They recently noticed that Phobos and MAVEN were going to cross the same point in space within about 7 seconds of each other on March 6, so they intervened. They will now miss each other by about 2.5 minutes.
“Kudos to the JPL navigation and tracking teams for watching out for possible collisions every day of the year, and to the MAVEN spacecraft team for carrying out the maneuver flawlessly,” MAVEN Principal Investigator Bruce Jakosky of the University of Colorado in Boulder said in a statement.
MAVEN has been instrumental in understanding how Mars deteriorated from a planet of flowing waters with a rich atmosphere. In 2015, astronomers used the incredible data from MAVEN to estimate the rate of atmospheric loss of the Red Planet and found evidence that the solar wind is responsible for blowing the Martian atmosphere away.
MAVEN has enough fuel to continue its science mission (and avoid moons) until late 2018, after which it could later be turned into a telecom satellite in a more circular orbit.