Spaceflight Insider

MAVEN avoids crashing into Mars’ moon Phobos

NASA's MAVEN spacecraft in orbit above the Red Planet. Image Credit NASA posted on SpaceFlight Insider

An artist’s illustration of NASA’s MAVEN spacecraft in orbit above the Red Planet. Image Credit: NASA

NASA’s Mars Atmosphere and Volatile EvolutioN, or MAVEN, spacecraft just avoided colliding with Phobos, one of Mars’ two moons. An avoidance maneuver was performed on Feb. 28, 2017, to safely alter the trajectory of the orbiter.

MAVEN’s engines fired to change the velocity of the spacecraft by less than 1 mph (about 0.4 meters per second). This ensured the spacecraft would miss Phobos by about 2.5 minutes on its March 6, 2017, closest approach.

Phobos: Doomed Moon of Mars

Phobos is one of two moons of Mars – the other is Deimos. Photo Credit: NASA / JPL-Caltech / University of Arizona

Before the maneuver, the two objects would have crossed paths within 7 seconds of each other. However, with Phobos being nearly 19 miles (30 kilometers) long at its widest, that was too close for comfort for NASA as it had a very high likelihood of collision.

This was MAVEN’s first collision avoidance maneuver since it began circling Mars in 2013. The spacecraft’s elliptical orbit around the planet crosses other spacecraft’s orbits as well as Phobos’ many times over the duration of a year. As the paths of all of these objects are well known and monitored by NASA’s Jet Propulsion Laboratory, these events are usually known well in advance.

“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,” said MAVEN Principal Investigator Bruce Jakosky in a news release.

An increasingly busy place

Currently, there are six spacecraft orbiting the planet. The most recent spacecraft, the European Space Agency’s (ESA) ExoMars Trace Gas Orbiter, arrived in Fall 2016. ESA also has the Mars Express spacecraft, which has been orbiting the Red Planet since 2003.

In addition to MAVEN, the United States’ spacecraft circling Mars include the Mars Reconnaissance Orbiter and Mars Odyssey – orbiting since 2005 and 2001, respectively.

India also has a spacecraft orbiting the Red Planet. Its Mars Orbiter Mission, also called Mangalyaan, has been circling Mars since 2014.

On the surface, there are two NASA rovers: Opportunity, which landed in 2004, and Curiosity, which landed in 2012.

Since 2014, there has been a record number of active missions on or around the Red Planet: seven from 2014 to 2015, and eight from 2016 to 2017.

Spacecraft around Mars

A graphical representation of the orbits of five of the current six spacecraft circling Mars. ESA’s Trace Gas Orbiter arrived after this graphic was created. It resides in a circular low-Mars orbit of 250 miles (400 kilometers) inclined by 74 degrees. Image Credit: NASA



Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity. You can find him on twitter @TheSpaceWriter.

Reader Comments

Good article but the headline seems a bit tabloidlish.

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