Soyuz TM-23 was a Soyuz spaceflight which launched on February 21, 1996, to Mir. The spacecraft launched from Baikonur Cosmodrome, and after two days of flight, Yuri Onufrienko and Yury Usachov docked with Mir and became the 21st resident crew of the Station.
Mir Principal Expedition 21
thumb|Mir February 23–29, 1996
February 1996 – Mir 21 begins
Progress M-30 Undocked and Soyuz TM-23 Launched
On February 21, Soyuz TM-23 launched from Baikonur Cosmodrome with the cosmonauts for Mir Principle Expedition 21. To clear a docking port for the Soyuz TM-23, the Progress M-30 was undocked on February 22 and re-entered over the Pacific Ocean. The Soyuz docked on February 23 at the +X docking port on the rear of the Kvant module. An hour and a half after docking, the hatches opened and the Soyuz TM-23 crew were greeted by Yuri Gidzenko, Sergei Avdeyev and Thomas Reiter, members of Mir Principle Expedition 20 and Euromir 95. This began a week of joint operations where Mir 20 handed the station over to Mir 21, including familiarization with the current conditions of the projects and the station itself. Two days before the return flight, a water leak appeared in the Mir base block, but the cosmonauts were able to repair it.
March 1996 – Atlantis visits Mir for the third time
First EVA for Mir 21
On March 15, Onufrienko and Usachev exited the Kvant 2 EVA hatch for their first space walk. Because the existing Strela could not be used to reach the Kristall module in its current location, they installed a second Strela boom on the Mir base block, on the side opposite the Strela already in place. In the 5-hour, 51-minute EVA, they also prepared cables and electrical connectors on the surface of the Kvant module for the May installation of the Mir Cooperative Solar Array. The array was stored on the surface of the Docking Module that was installed on Kristall last November.