correcting properties of this Hadamard code were much better, yet its data rate was comparable. The efficient decoding algorithm was an important factor in the decision to use this code. The circuitry used was called the "Green Machine", which employed the fast Fourier transform, increasing the decoding speed by a factor of three. Present location As of February 2022, Mariner 9's location is unknown; it is either still in orbit, or has already burned up in the Martian atmosphere or crashed into the surface of Mars. NASA has provided multiple dates for when Mariner 9 could enter the Martian atmosphere. In 2011, NASA predicted that Mariner 9 would burn up or crash into Mars around 2022. However, a 2018 revision to the Mariner 9 mission page by NASA expected Mariner 9 would crash into Mars "sometime around 2020". At the time of the mission, Mariner 9 was left in an orbit that would not decay for at least 50 years, which placed the earliest date of atmospheric entry to October 2022. See also Exploration of Mars List of Mars orbiters List of missions to Mars Space exploration Timeline of artificial satellites and space probes Unmanned space missions Mars flyby References External links Mariner 9 Mission Profile by NASA's Solar System Exploration NSSDC Master Catalog: Spacecraft – Mariner 9 NASA-JPL Guide to Mariner 9 some Mariner 9 images of Mars Mariner 9 approaching Mars movie Mariner 9 images, including dust storm Mariner 9 view of Phobos (hosted by The Planetary Society) Mariner 9 image compared to MGS image, helps determine if Dunes moved in decades P.418 Correct DN values appear to be 512, not 64 i.e. 9bits per pixel Mariner program Missions to Mars 1971 in spaceflight Derelict satellites orbiting Mars Derelict space probes Spacecraft launched by Atlas-Centaur rockets Spacecraft launched in 1971 Geography of Mars