Luna 5

Luna 5, or E-6 n°10, was an unmanned Soviet spacecraft intended to land on the Moon as part of the Luna programme. It was intended to become the first spacecraft to achieve a soft landing on the Moon, however its retrorockets failed, and the spacecraft impacted the lunar surface. Following the mid-course correction on 10 May, the spacecraft began spinning around its main axis due to a problem in a flotation gyroscope in the I-100 guidance system unit. A subsequent attempt to fire the main engine failed because of ground control error, and the engine never fired. As a result of these failures, the soft landing attempt failed, and Luna 5 impacted the Moon. The place of impact was firstly announced as 31°S 8°W (coast of Mare Nubium), but later it was estimated as 8°N 23°W (near crater Copernicus). It was the second Soviet spacecraft to reach the surface of the Moon, following Luna 2 in 1959. The Abastumani Astrophysical Observatory registered television images of the failed landing noted that shown it produced a 220-by-80-kilometre plume which was visible for ten minutes. A 2017 analysis of the reprocessed images allowed to refine the impact coordinates, provide an altitude estimate of 3.7−3.9 km for the generated gas cloud and corroborate estimations published for the 2009 LCROSS impact.