The Voskhod-3KD was a Soviet manned spacecraft modified from the Voskhod-3KV and closely based on the Vostok-3K capsule. It was capable to carry crews of two cosmonauts and enabled spacewalks.

The basic difference to Vostok was the elimination of the ejector seat to make room for two cosmonauts in spacesuits. To soften the landing, a solid fuel retro rocket was incorporated. Also a solid fuel back-up retro rocket system was carried in front of the spherical reentry capsule. The 3KD version carried an external inflatable airlock, allowing for spacewalk. After spacewalk, the airlock was jettisoned.

Voskhod 2 was a manned flight with a two men crew (Belyayev and Leonov). Leonov performed the first spacewalk ever, but had problems reentering the inflated airlock. After the airlock was jettisoned, a slow decrease of air pressure was noticed, leading to a earlier than planned return to earth. The capsule reentered safely after a 26 hour flight, but landed in the Ural mountains, nearly 1000 km north of the originally planned landing site. The crew was rescued about 1 day after landing.