Astronomers working at NASA's Jet Propulsion Laboratory helped save the MAVEN Mars orbiter from colliding with the red planet's moon Phobos.

Potential Space Collision

The Mars Atmosphere and Volatile EvolutioN mission (MAVEN), which has been orbiting Mars for two years now, was expected to cross paths with Phobos on March 6. Computer models revealed that the $671 million spacecraft and Phobos would miss each other by a mere seven seconds, raising concern for potential collision.

Mission controllers took preventive action on Feb. 28, firing the orbiter's engine so its velocity would increase and give a relatively safer 2.5 minutes between Phobos and Maven.

The U.S. space agency has already boosted its traffic monitoring, communication, and maneuver-planning in a bid to ensure that the orbiters circling Mars would not get too near each other.

Nonetheless, while NASA has prevented Maven from colliding with a Martian moon, this is not as easy when it comes to preventing space object collisions near Earth.

Satellite Collisions Above Earth

While satellite operators can direct spacecraft orbiting Earth to do a similar maneuver in seconds compared with 13 minutes for spacecraft on the red planet, Earth has far more satellites orbiting it, which makes preventing space collisions more difficult.

Less than 10 spacecraft are currently orbiting Mars. Earth, on the other hand, has more than 1,400 operational man-made satellites.

"Traffic management at Mars is much less complex than in Earth orbit, where more than 1,000 active orbiters plus additional pieces of inactive hardware add to hazards," NASA stated.


Besides the increasing number of Earth's satellites, CubeSats also pose concern. The miniature satellites are relatively low-cost they can be afforded by small companies and universities.

The objects, however, are not maneuverable, which means they cannot be steered to avoid collision with other space objects. As more of these CubeSats get launched into Earth's orbit, experts warn of more frequent space collisions as these may hit and cause damage to other objects in orbit.

In 2014, space debris expert Hugh Lewis, from the University of Southampton, and colleagues used computer models to simulate these small satellites' traffic until the year 2043. They discovered that there will be millions of close calls with CubeSats and a few of these miniature satellites will collide with other space objects over the next three decades.

Space Junk

Space junk is also a problem. About 100 million debris of space junk, which include discarded equipment from satellites, tools, and pieces of rockets are believed to be in Earth's orbit. Many of these pieces are small, but with velocities reaching up to 12,500 miles per hour, they can whiz through space and potentially cause damage to satellites or even space stations.

"Debris hitting debris creates more debris, so you have this cascade effect and end up with so much space debris that it becomes a real danger to operational satellites and new launches," said Steve Gower of the Space Environment Research Center in Australia. "Every time we launch a satellite, we need to plan a path to avoid space junk."

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