Phew! Mars Orbiters Safely Dodge Comet Siding Spring

NASA's three state-of-the-art Mars orbiters successfully dodged a comet and its dangerous debris just yesterday, after months of preparation for this rare fly-by event.

As far as we know, the comet Siding Spring (C/2013 A1) is a new visitor to our solar system, whipping in from the outer Oorty Cloud. Considering its possible origins, experts suspect that the comet is a very old heavenly body, and may yield fresh clues about our solar system's earliest days more than four billion years ago.

On Sunday, Oct. 19, Siding Spring whipped by Mars within a mere 88,000 miles of the planet. And while tens-of-thousands of miles doesn't sound all that close, it still posed a significant threat to Mars Odyssey, the Mars Reconnaissance Orbiter, and the Mars Atmosphere and Volatile Evolution (MAVEN) orbiter.

NASA experts were worried that before burning up in the planet's atmosphere, debris shredded from the comet might come hurtling towards Mars' orbiting spacecraft at up to 35 miles per second. For perspective, the average bullet travels a little less than half a mile per second.

A collision with even a tiny chunk of ice hurtling at such an incredible speed could prove catastrophic for a manmade satellite. So NASA launched a "duck and cover" mission, in which all three orbiters temporarily shifted to the other side of the Red Planet as Siding Spring whipped by. (Scroll to read on...)

[Credit: NASA/JPL-Caltech]

Not an agency to pass up a scientific opportunity, NASA technicians had pre-programmed all three orbiters to take careful measurements of the comet and potential effects its fly-by might have on Mars' delicate atmosphere - even as all three orbiters safely waited out of harm's way and out of communication range with Earth.

"The telemetry received from Odyssey this afternoon confirms not only that the spacecraft is in fine health but also that it conducted the planned observations of comet Siding Spring within hours of the comet's closest approach to Mars," Odyssey Mission Manager Chris Potts excitedly announced Sunday afternoon following the fly-by.

Techs had been worried about Odyssey, as it is the longest-lived robot ever sent to Mars, but it came out of this latest challenge unscathed.

The Mars Reconnaissance Orbiter and the brand-new MAVEN also survived the ordeal, collecting data with 13 other spacecraft and observatories in the process.