The orbit of NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft sometimes crosses the orbit of the planet’s inner moon, Phobos. This image shows the configuration of the two orbits in early December 2015, when MAVEN’s Phobos observations were made. Image credits: CU/LASP and NASA.Orbiting a mere 3,700 miles (6,000 kilometres) above the surface of Mars, Phobos is closer to its planet than any other moon in the solar system. Mars’ gravity is drawing in Phobos, the larger of its two moons, by about 6.6 feet (2 metres) every hundred years. Scientists expect the moon to be pulled apart in 30 to 50 million years.
Other than gathering evidence of its eventual fate, NASA scientists are also closer to solving the mystery of how Mars’ moon Phobos formed.
In late November and early December 2015, NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission made a series of close approaches to the Martian moon Phobos, collecting data from within 300 miles (500 kilometres) of the moon.Phobos as observed by MAVEN’s Imaging Ultraviolet Spectrograph. Orange shows mid-ultraviolet (MUV) sunlight reflected from the surface of Phobos, exposing the moon’s irregular shape and many craters. Blue shows far ultraviolet light detected at 121.6 nm, which is scattered off of hydrogen gas in the extended upper atmosphere of Mars. Phobos, observed here at a range of 300 kilometres, blocks this light, eclipsing the ultraviolet sky. Image credits: CU/LASP and NASA.The observations were made by the Imaging Ultraviolet Spectrograph instrument aboard MAVEN. Among the data returned were spectral images of Phobos in the ultraviolet. The images will allow MAVEN scientists to better assess the composition of this enigmatic object, whose origin is unknown.
Comparing MAVEN’s images and spectra of the surface of Phobos to similar data from asteroids and meteorites will help planetary scientists understand the moon’s origin — whether it is a captured asteroid or was formed in orbit around Mars. The MAVEN data, when fully analysed, will also help scientists look for organic molecules on the surface. Evidence for such molecules has been reported by previous measurements from the ultraviolet spectrograph on ESA’s Mars Express spacecraft.
On the morning of Sunday, 22 May planet Mars reached opposition in the constellation of Scorpius and is closest to the Earth on 30 May — its best showing in a decade for Southern Hemisphere observers. As seen from the UK the Red Planet will be low in the south at 1am BST, but on nights of good seeing surface detail will be visible in amateur telescopes. Use our interactive Mars Mapper to identify its features.
NASA announced Thursday it will fund development of a scientific instrument that will fly on Japan’s Martian Moons Exploration mission, a robotic probe set for launch in 2024 to bring back the first samples from Mars’ largest moon Phobos.
A rover NASA plans to launch to Mars in 2020 will likely explore one of three locations selected last week by a scientific advisory group, which picked candidate landing sites that were once homes to ancient lakes and hot springs.
