Venera 2MV-2 No.1, also known as Sputnik 21 in the West, was a Soviet spacecraft, which was launched in 1962 as part of the Venera programme, and was intended to make a flyby of Venus. Due to a problem with the rocket which launched it, it failed to leave low Earth orbit, and reentered the atmosphere a few days later. It was the second Venera 2MV-2 spacecraft, both of which failed to leave Earth orbit.