A comet from another star system will swing by Mars on Friday as a fleet of spacecraft trains its sights on the interstellar visitor.
The comet known as 3I/Atlas will hurtle within 18 million miles (29 million kilometers) of the red planet, its closest approach during its trek through the inner solar system. Its breakneck speed: 193,000 mph (310,000 kph).
Both of the European Space Agency's satellites around Mars are already aiming their cameras at the comet, which is only the third interstellar object known to have passed our way. NASA's satellite and rovers at the red planet are also available to assist in the observations.
Discovered in July, the comet poses no threat to Earth or its neighboring planets. It will come closest to the sun at the end of October. Throughout November, ESA's Juice spacecraft, which is headed to Jupiter and its icy moons, will keep an eye on the comet.
The comet will make its closest approach to Earth in December, passing within 167 million miles (269 million kilometers).
Observations by the Hubble Space Telescope put the comet's nucleus at no more than 3.5 miles (5.6 kilometers) across. It could be as small as 1,444 feet (440 meters), according to NASA.
