Yuri and Sergei before spacewalk

Cosmonauts Yuri Malenchenko and Sergei Volkov wave to NASA commander Scott Kelly before exiting the International Space Station's Pirsk airlock for a five-hour spacewalk.

They placed new experiments on the outpost's hull and retrieved ESA's Expose facility on 3 February 2015.

Expose is a series of chemistry laboratories that place samples in the harsh environment of space unprotected. Subjected to vacuum, radiation, temperature differences and the full blast of our Sun’s energy, 46 species of small organisms and over 150 organic compounds have returned after spending 18 months bolted to the Zvezda module.