Mars spacecraft moved as comet nears red planet
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.