Duck-and-cover time for Mars spacecraft as comet nears

An artist drawing of Comet Siding Spring approaching Mars.

Story highlights

  • Comet Siding Spring to fly close to Mars
  • NASA will move its orbiters to dodge comet dust
  • A fleet of space probes will observe the comet
A comet is speeding toward a close-encounter with Mars. Comet Siding Spring is expected to come within 87,000 miles of Mars at about 2:27 p.m. ET on Sunday -- very close for a comet flyby. The space rock is moving at about 126,000 mph (56 kilometers per second).
NASA thinks the comet will miss the Red Planet, but comets spew out a trail of dust and gas, and that could damage the fleet of spacecraft orbiting Mars.
"Mars will be right at the edge of the debris cloud, so it might encounter some of the particles -- or it might not," Rich Zurek, chief scientist for the Mars Exploration Program at NASA's Jet Propulsion Laboratory said in a press release.
"It only takes a half-a-millimeter-sized particle traveling at 56 kilometers per second to injure one of these spacecraft," Don Yeomans, manager of the Near Earth Object Program Office said in a NASA video.
Just to be safe, NASA will move the Mars Odyssey orbiter, Mars Reconnaissance Orbiter (MRO), and the new Mars Atmosphere and Volatile EvolutioN (MAVEN) to the other side of the planet as the comet approaches.
"We're going to hide behind Mars," said Rob Lock, Orbiter Studies Lead in the Mars Program Office. "Kind of like diving under your desk if there's an earthquake and flying glass around."
The orbiters will take pictures and collect data on the comet as it zips by. Several Earth-based and space telescopes, including the Hubble Space Telescope, also will take pictures.
What about the probes on the surface of Mars? NASA says the rovers are safe and will be protected by Mars' atmosphere.