Two Russian cosmonauts have completed their six-hour spacewalk without accomplishing all the tasks as planned.

Alexander Samokutyaev and Sergei Volkov launched an educational satellite during the spacewalk Wednesday. The launch was delayed after the cosmonauts discovered that one of its antennas was missing. They eventually released the 26-kilogram satellite with only one antenna, which will diminish its performance.

The delay prevented the two cosmonauts from completing another major task — moving a Russian cargo crane from one part of the International Space Station to another.

Before returning into the space station, Samokutyaev and Volkov photographed the portraits of three Soviet space program pioneers: Yuri Gagarin, the first man to fly into space, spacecraft designer Sergei Korolyov and rocket scientist Konstantin Tsiolkovsky. The portraits were taken out of the space station and photographed with Earth in the background.

The next spacewalk is expected in February.