Kosmos 901 (Russian: Космос 901 meaning Cosmos 901), also known as DS-P1-I No.18 was a satellite which was used as a radar target for anti-ballistic missile tests. It was launched by the Soviet Union in 1977 as part of the Dnepropetrovsk Sputnik programme. It was launched aboard a Kosmos-2I 63SM rocket, from Site 133/1 at Plesetsk. The launch occurred at 10:30 UTC on 5 April 1977. Kosmos 901 was the eighteenth of nineteen DS-P1-I satellites to be launched. Of these, all reached orbit successfully except the seventh.