Moons of Mars attention when Houston's claim was repeated in earnest by a Soviet scientist, Iosif Shklovsky, who, based on a later-disproven density estimate, suggested Phobos was a hollow metal shell. Searches have been conducted for additional satellites. In 2003, Scott S. Sheppard and David C. Jewitt surveyed nearly the entire Hill sphere of Mars for irregular satellites. However scattered light from Mars prevented them from searching the inner few arcminutes where the satellites Phobos and Deimos reside. No new satellites were found to an apparent limiting red magnitude of 23.5, which corresponds to radii of about 0.09 km using an albedo of
Mars One in 2012 was Astrobotic Technology. On 12 March 2013, Paragon Space Development Corporation was contracted to develop concepts for life support and the Mars Surface Exploration Spacesuit System, and it includes the pressure suit and the Portable Life Support System (PLSS) that permit survival outside the habitat. The suggested supplier of the suits is ILC Dover. The study was stated to be finished late summer 2013; Mars One released the results of this (ECLSS portion only) study to the public in June 2015, but did not fund its research and development. In 2013, Mars One signed a contract with Paragon