Cosmos 305 (Ye-8-5 series) was the fifth Soviet attempt at an unmanned lunar sample return. It was probably similar in design to the Luna 16 spacecraft. It was launched, on a Proton rocket, on October 11, 1969. The mission was a failure. The engines on the Block D upper stage failed leaving the spacecraft stranded in Earth orbit. Bulk silicate composition (estimated wt%) SiO2 44. ... Luna 16 was an unmanned space mission of the Luna program, also called Lunik 16. ... The Proton (ÐÑоÑоÌн) rocket (formal designation: UR-500, also known as D-1/ D-1e or SL-12/SL-13) is a Russian unmanned space vehicle design, first launched in 1965. ...
Cosmos 300 (Ye-8-5 series) was the fourth Soviet attempt at an unmanned lunar sample return. ... The Luna programme (occasionally called Lunik) was a series of unmanned space missions sent to the Moon by the Soviet Union between 1959 and 1976. ...