Kosmos 101

Kosmos 101 (Космос 101 meaning Cosmos 101), also known as DS-P1-Yu No.4 was a Soviet satellite which was used as a radar calibration target for tests of anti-ballistic missiles. It was built by the Yuzhnoye Design Bureau, and launched in 1965 as part of the Dnepropetrovsk Sputnik programme.

The launch of Kosmos 101 was conducted using a Kosmos-2I 63S1 carrier rocket, which flew from Site 86/1 at Kapustin Yar. The launch occurred at 06:14 GMT on 21 December 1965.

Kosmos 101 separated from its carrier rocket into a low Earth orbit with a perigee of 254 km, an apogee of 539 km, an inclination of 49.0°, and an orbital period of 92.4 minutes. It decayed from orbit on 12 July 1966. Kosmos 101 was the fourth of seventy nine DS-P1-Yu satellites to be launched, of which all but seven were successful.