Exploration of Mars failed upon impact. Mars 4 flew by the planet at a range of 2200 km returning one swath of pictures and radio occultation data, which constituted the first detection of the nightside ionosphere on Mars. Mars 7 probe separated prematurely from the carrying vehicle due to a problem in the operation of one of the onboard systems (attitude control or retro-rockets) and missed the planet by . In 1964, NASA's Jet Propulsion Laboratory made two attempts at reaching Mars. Mariner 3 and Mariner 4 were identical spacecraft designed to carry out the first flybys of Mars. Mariner 3 was launched
Human mission to Mars were for a launch sometime between 2016 and 2020. The Mars probe would carry a crew of four to five cosmonauts, who would spend close to two years in space. In late 2011, Russian and European space agencies successfully completed the ground-based MARS-500. The biomedical experiment simulating crewed flight to Mars was completed in Russia in July 2000. In 2011, Jean-Marc Salotti published a new proposal for a crewed Mars mission, with a release in 2012. The 2-4-2 concept is based on a reduction of the crew size to only 2 astronauts and the duplication of the entire mission. There