Two astronauts, attached to a robotic arm, service Hubble above the Earth, which takes up the whole background.

Hubble SM 3A EVA

Steven L. Smith (right) and John M. Grunsfeld (left) use the RMS robotic arm to perform servicing tasks on the temporarily-captured Hubble Space Telescope (HST) during the third HST servicing mission (SM 3A), in December 1999.

Credits: NASA