C. Michael Foale (left) and Claude Nicollier replace a Fine Guidance Sensor on Hubble.

C. Michael Foale (left) and Claude Nicollier participate in the second of three STS-103 spacewalks to service the Hubble Space Telescope (HST). On this outing they replaced a Fine Guidance Sensor (FGS). Nicollier, a European Space Agency (ESA) astronaut, stood on the end of the Remote Manipulator System (RMS) robotic arm.