Classic Bob Zimmerman: Searching for the Soviet Mars 3 and the War between the Phobosians and the Russians, April 2013. Bob Zimmerman

Feb 19, 2018, 06:48 AM


(Photo: Phobos (/ˈfoʊbəs/ FOH-bəs or /ˈfoʊbɒs/ FOH-bos,[4] from the Greek Φόβος.) (systematic designation: Mars I) is the innermost and larger of the two natural satellites of Mars,[5] the other being Deimos. Both moons were discovered in 1877 by American astronomer Asaph Hall.

Phobos is a small, irregularly shaped object with a mean radius of 11 km (7 mi),[1] and is seven times as massive as the outer moon, Deimos. Phobos is named after the Greek god Phobos, a son of Ares (Mars) and Aphrodite (Venus), and the personification of horror (cf. phobia).

Phobos orbits 6,000 km (3,700 mi) from the Martian surface, closer to its primary body than any other known planetary moon. It is indeed so close that it orbits Mars much faster than Mars rotates, and completes an orbit in just 7 hours and 39 minutes. As a result, from the surface of Mars it appears to rise in the west, move across the sky in 4 hours and 15 minutes or less, and set in the east, twice each Martian day.

Phobos is one of the least reflective bodies in the Solar System, with an albedo of just 0.071. Surface temperatures range from about −4 °C (25 °F) on the sunlit side to −112 °C (−170 °F) on the shadowed side.[6] The defining surface feature is the large impact crater, Stickney, which takes up a substantial proportion of the moon's surface.

Images and models indicate that Phobos may be a rubble pile held together by a thin crust, and that it is being torn apart by tidal interactions.[7] Phobos gets closer to Mars by about 2 meters every one hundred years, and it is predicted that within 30 to 50 million years it will either collide with the planet, or break up into a planetary ring.[6])

Twitter: @BatchelorShow

Classic Bob Zimmerman: Searching for the Soviet Mars 3 and the War between the Phobosians and the Russians, April 2013. Bob Zimmerman

The citizen enthusiasts, led by Vitali Egorov of St. Petersburg, Russia, undertook a crowdsourcing effort to search for the vehicle in photos of the projected landing site from the Mars Reconnaissance Orbiter (MRO), which has been circling Mars since 2006. MRO launched toward the Red Planet in 2005 and is NASA's youngest and most powerful orbiter to study Mars from above.

In an image from 2007, they found features that resemble the Mars 3 lander, along with its parachute, heat shield, and terminal retrorocket. The features are the right size and shape for the equipment, and they're arranged in the configuration expected from the mission's entry, descent and landing plan, but it's too early to say for sure whether the photo actually depicts Mars 3.

"I wanted to attract people's attention to the fact that Mars exploration today is available to practically anyone," Egorov said in a NASA statement. "At the same time we were able to connect with the history of our country, which we were reminded of after many years through the images from the Mars Reconnaissance Orbiter."