Extraterrestrial skies Mars appears to be the angular diameter as seen from Earth (0.35°), and sends 40% of the light, approximately the brightness of a slightly cloudy afternoon on Earth. On June 3, 2014, the "Curiosity" rover on Mars observed the planet Mercury transiting the Sun, marking the first time a planetary transit has been observed from a celestial body besides Earth. Mars has two small moons: Phobos and Deimos. From the Martian surface, Phobos has one-third to one-half the angular diameter of the Sun while Deimos is barely more than a dot (only 2′ angular diameter). The orbital period of Phobos
Phobos 2 to approach within of Phobos' surface and release two landers, one a mobile , the other a stationary platform, contact with "Phobos 2" was lost. The mission ended when the spacecraft signal failed to be successfully reacquired on 27 March 1989. The cause of the failure was determined to be a malfunction of the on-board computer. The "Phobos 2" infrared spectrometer (ISM) obtained 45000 spectra in the near infrared (from ) in the equatorial areas of Mars, with a spatial resolution ranging from , and 400 spectra of Phobos at 700 m resolution. These observations made it possible to retrieve