NASA Mars Spacecraft Ready for Rare Encounter With Comet

— -- A comet will hurtle past Mars next weekend, nearly missing the Red Planet but providing a once-in-a-lifetime show that will be captured by NASA's fleet of spacecraft.

Comet Siding Spring will pass within 87,000 miles of Mars on Sunday, Oct. 19 -- that's about one-third the distance between the Earth and the moon.

The comet is expected to come closest to Mars at 2:27 p.m. ET that day, moving at about 34 miles per second.

NASA moved its fleet of orbiting vehicles so they won't be impacted by dust particles from the comet. However, the fleet, including the newly arrived MAVEN, will be in a position to gather information about the size, rotation and gas composition of Siding Spring, agency officials said.

John Grunsfeld, astronaut and associate administrator for NASA's Science Mission Directorate, called next Sunday's event a "cosmic science gift that could potentially keep on giving."

"This particular comet has never before entered the inner solar system, so it will provide a fresh source of clues to our solar system's earliest days," Grunsfeld said in a statement.

The comet is comprised of icy debris that researchers believe are remnants from the formation of the solar system. Its dramatic brush past the Red Planet is expected to yield new insights into the materials that existed during the formation of the solar system 4.6 billion years ago.