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 2024, and one in 2026 which would not be returning to Earth. Although the announcement garnered much international publicity, the concept has been criticized by scientists, engineers, and those in the aerospace industry. Mars One is noted as being very short on funding, lacking critical concepts about hardware, life support, electrical power supply, and has been criticized as glossing over logistics, medical concerns, and protection against space radiation. The concept has been called a suicide mission both in academia, spaceflight, and international news. By February 2015, two conceptual studies were done by contractors. Despite the criticism and lack of