Comet Siding Spring near Mars.
Composite NASA Hubble Space Telescope image of the positions of planet Mars and comet Siding Spring during the comet’s close pass by the planet (with a distance at closest approach of about 87,000 miles), approx. 2:28 p.m. EDT, October 19, 2014.
From NASA’s press release:
NASA used its extensive fleet of science assets, particularly those orbiting and roving Mars, to image and study this once-in-a-lifetime comet flyby. In preparation for the comet flyby, NASA maneuvered its Mars Odyssey orbiter, Mars Reconnaissance Orbiter (MRO), and the newest member of the Mars fleet, Mars Atmosphere and Volatile EvolutioN (MAVEN), in order to reduce the risk of impact with high-velocity dust particles coming off the comet.
(Just another reminder that Mars — and the orbital space around Mars — is at present
populated solely by robots.)
Image Credit: NASA, ESA, PSI, JHU/APL, STScI/AURA. Source: Wikimedia Commons.