NASA's Mars Orbiter Narrowly Avoids Collision with Martian Moon

Fagjun | Published 2017-03-03 22:44

NASA is certainly having an exciting week.

Flight control personnel managed to steer spacecraft MAVEN away from a collision course with the Martian moon Phobos.

On February 28, 2017, researchers noticed that MAVEN's orbit will take the spacecraft uncomfortably close to Phobos. If MAVEN's trajectory were left unchecked, it would cross the same orbital point as Phobos within just seven seconds. With that kind of distance, there would be a possibility that the two satellites would collide into each other. Researchers calculated that the two satellites would come to that point on March 6.

NASA to the Rescue

Therefore, NASA had a week to maneuver MAVEN away from Phobos's orbit. Flight control assessed what MAVEN had to do in order to take itself further away from Phobos. All it took was a slight alteration to MAVEN's speed to avoid a collision. MAVEN fired up its thrusters and boosted its speed by 1.5 kilometers per hour. It may seem like a small change, but it definitely sufficed. The spacecraft managed to speed up just enough and take itself far enough away from Phobos.

"Kudos to the [Jet Propulsion Laboratory] 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," said Bruce Jakosky, MAVEN principal investigator. Because of this evasive maneuver, the two satellites will cross the same orbital point 2.5 minutes apart. That's enough time for each satellite to completely avoid one another.

Officials stated that this was the first time the spacecraft had to avoid another satellite. Changes to a spacecraft's trajectory to evade a planet's moon are actually quite rare.


MAVEN's orbit around Mars
[Photo credit: NASA]

The spacecraft MAVEN—short for Mars Atmospheric and Volatile Evolution—has been orbiting Mars since September 2014. It has an elongated orbit that regularly crosses Phobos's orbit and those of NASA's other Mars orbiters. At the peak of its orbit, MAVEN reaches a point 44,500 kilometers away from the surface of Mars.

MAVEN's mission is to discover how Mars lost much of its atmosphere. The shape of MAVEN's orbit allows it to study Mars up close and from afar. When it comes close to the planet, it can take measurements of the upper layers of the planet's atmosphere.

The spacecraft was able to discover that solar winds stripped Mars of much of its atmosphere. MAVEN also discovered that Mars lost the most water at its closest point to the sun. These, among other discoveries, were significant achievements in the spacecraft's mission.


The potato-like Martian moon is spiraling closer and closer to the planet. [Photo credits: NASA/JPL-Caltech/University of Arizona]

In December 2015, MAVEN came close to Phobos, though not at a perilous proximity. The spacecraft was able to take measurements of the Martian moon, which can help determine Phobos's origin.

Phobos is an oddly-shaped moon that revolves around Mars three times a day. Its lumpy, crater-ridden surface makes it look a little like a potato. It is circling closer and closer to Mars, and scientists predict that it will eventually collide into the planet. That collision, fortunately, is something that NASA and MAVEN have nothing to do with.

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