Astronauts at Work on Hubble (IMAGE) ESA/Hubble Information Centre Caption Astronauts Andrew Feustel (partially obscured at top) and John Grunsfeld work to install the new Cosmic Origins Spectrograph onboard the NASA/ESA Hubble Space Telescope on the third spacewalk of Servicing Mission 4. Credit NASA Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.