Kosmos 400 (Russian: Космос 400 meaning Cosmos 400), also known as DS-P1-M No.3 was a satellite which was used as a target for tests of anti-satellite weapons.

It was launched by the Soviet Union in 1971 as part of the Dnepropetrovsk Sputnik programme,[1] and used as a target for Kosmos 404, as part of the Istrebitel Sputnikov programme.

[2] It was launched aboard a Kosmos-3M carrier rocket,[3] from Site 132/1 at the Plesetsk Cosmodrome.

[4] Kosmos 400 was placed into a low Earth orbit with a perigee of 990 kilometres (620 mi), an apogee of 995 kilometres (618 mi), 65.8 degrees of inclination, and an orbital period of 105 minutes.

Following the five initial launches the DS-P1-M satellite was replaced with a derivative, Lira.