timeline of EVAs for Hubble SM4
Proposed NASA Official Mission EVA Timeline - View PowerPoint version with EVA Priority List

The astronauts performed five spacewalks, or extravehicular activities (EVAs), to upgrade and enhance Hubble's capabilities. The EVAs were conducted on consecutive days during the flight with spacewalkers pairing off into two teams. The spacewalks varied in length but they generally were around seven hours each.

EVA Team 1, composed of astronauts John Grunsfeld and Drew Feustel, conducted the first, third and fifth spacewalks. EVA Team 2, astronauts Mike Massimino and Mike Good, conducted the second and fourth spacewalks. Astronaut Megan McArthur was the primary operator of the shuttle robotic arm.

EVA 1 (Team 1)

  • New instrument, Wide Field Camera 3 (WFC3) installed in the Aft Shroud radial bay, replacing Wide Field Camera 2 (WFPC-2).
  • Bay 10 SIC&DH module replaced.
  • Installed SCM component to Hubble's aft bulkhead.
  • Lubricated three of the shroud doors
  • Installed one of the three latch-over center kits (LOCK) on the -V2 doors. A second LOCK was partially installed.
  • Installed a latch repair to one of the -V2 door bolts
  • EVA start: 12:52, EVA finish: 20:12, Duration: 7 hours 20 minutes.

EVA 2 (Team 2)

  • Replaced all six gyroscopes (housed in three Rate Sensor Units (RSU), holding 2 gyros each). One RSU had to be replaced with a refurbished unit due to a seating problem.
  • Bay 2 Battery module replaced.
  • EVA start: 12:49, EVA finish: 20:45, Duration: 7 hours 56 minutes. Ninth-longest spacewalk in history.

EVA 3 (Team 1)

  • New Instrument Cosmic Origins Spectrograph (COS) was installed, replacing COSTAR.
  • Repair of the Advanced Camera for Surveys (ACS), which failed on Jan. 27, 2007.
  • EVA start: 13:35, EVA finish: 20:11, Duration: 6 hours 36 minutes.

EVA 4 (Team 2)

  • Repair of the Space Telescope Imaging Spectrograph (STIS) which failed on Aug. 3, 2004.
  • Install New Outer Blanket Layer (NOBL) on Bay 8. (Postponed to EVA 5 due to time overrun on STIS repair)
  • EVA start: 13:45, EVA finish: 21:47, Duration: 8 hours 2 minutes. Sixth-longest spacewalk in history.

EVA 5 (Team 1)

  • Bay 3 Battery module replaced.
  • Replaced #2 Fine Guidance Sensor (FGS). The FGSs are used to lock onto and track guide stars.
  • Installed New Outer Blanket Layer (NOBL) on Bays 5, 7 and 8.
  • EVA start: 12:20, EVA finish: 19:22, Duration: 7 hours 2 minutes.