A comet is speeding to a nearby experience with Mars. Comet Siding Spring is required to come quite close to Mars at around 2:27 p.m. ET on Sunday – close for a comet flyby. The space rock is moving at around 126,000 mph (56 kilometers for every second).
NASA thinks the comet will miss the Red Planet, yet comets heave out a trail of dust and gas, and that could harm the armada of rocket circling Mars.