# List of Space Shuttle rollbacks

This is a list of Space Shuttle rollbacks. "Rollback" is the term NASA uses when the Space Shuttle was rolled back from the launch pad atop the mobile launcher platform and Crawler-transporter to the Vehicle Assembly Building (VAB). A variety of factors could require a rollback, from severe weather to the need for repairs that could not be performed at the launch pad. Shuttle rollbacks are listed in chronological order:
| No. | Date | Orbiter | Mission | Reason | Description |
| 1 | 1983-10-19 | Columbia | STS-9 | Inspection failure | Suspect exhaust nozzle on right solid rocket booster. Columbia was de-stacked and moved back to the Orbiter Processing Facility (OPF). |
| 2 | 1984-07-11 | Discovery | STS-41-D | Abort | Space shuttle main engine (SSME) #3 replaced after a launch abort. |
| 3 | 1985-03-05 | Challenger | STS-51-E STS-51-B | Payload | Challenger was rolled back from Pad 39A due to a timing problem with the primary payload, the Tracking and Data Relay Satellite-B (TDRS-B). The vehicle was de-stacked in the VAB and the orbiter returned to Orbiter Processing Facility. The mission, STS-51E, was canceled and the orbiter was re-manifested with 51-B payloads. |
| 4 | 1990-06-12 | Columbia | STS-35 | Inspection failure | A hydrogen leak was detected in External tank (ET) umbilical. |
| 5 | 1990-08-09 | Atlantis | STS-38 | Fuel leak | Atlantis was rolled back after tests confirmed a hydrogen fuel leak on the external tank side of the external tank/orbiter quick-disconnect umbilical. |
| 6 | 1990-10-09 | Columbia | STS-35 | Weather | Weather threat from Tropical Storm Klaus. |
| 7 | 1991-03-07 | Discovery | STS-39 | Inspection failure | Discovery was rolled back to the VAB after significant cracks were found on all four lug hinges on the two external tank umbilical door drive mechanisms. |
| 8 | 1994-08-24 | Endeavour | STS-68 | Abort | Pad abort due to a high discharge temperature in a pump on main engine number three. All three engines were replaced in the VAB. |
| 9 | 1995-06-08 | Discovery | STS-70 | Inspection failure | Yellow flicker woodpeckers drilled approximately 71 holes on the external tank foam insulation, many of which were too high up on the tank to be accessed at the pad for repairs. |
| 10 | 1995-08-01 | Endeavour | STS-69 | Weather | Endeavour was moved back to the VAB due to threat of severe weather from Hurricane Erin. |
| 11 | 1996-07-10 | Atlantis | STS-79 | Weather | Atlantis was moved back to the VAB due to threat of severe weather from Hurricane Bertha. |
| 12 | 1996-09-04 | Atlantis | STS-79 | Weather | Atlantis was moved back to the VAB due to threat of severe weather from Hurricane Fran. |
| 13 | 1999-05-16 | Discovery | STS-96 | Inspection failure | Discovery was moved back to the VAB to repair hail damage to the external tank foam insulation. |
| 14 | 2001-01-02 | Atlantis | STS-98 | Crawler failure | Atlantis began rollout to Launch Pad 39A, but an hour later stopped on the crawler path so engineers could troubleshoot a failed computer processor on the crawler transporter. Troubleshooting efforts were unsuccessful, the shuttle was returned to the VAB using a secondary computer processor. |
| 15 | 2001-01-19 | Atlantis | STS-98 | Inspection failure | Atlantis was returned to the VAB due to uncertainty involving the integrity of the SRB cables. |
| 16 | 2005-05-26 | Discovery | STS-114 | Component upgrade | Discovery was returned to the VAB in order to get a new, modified external fuel tank in preparation for the first Return to Flight mission following the Columbia accident. |
| 17 | 2006-08-29 | Atlantis | STS-115 | Weather | Atlantis was moved back towards the VAB due to threat of severe weather from Tropical Storm Ernesto. However halfway through rollback, they elected to return Atlantis to the Pad due to improvement in the weather forecast. |
| 18 | 2007-03-04 | Atlantis | STS-117 | Inspection failure | Atlantis was moved back to the VAB after a hail storm damaged the foam insulation on the orbiter's external tank, necessitating repairs. Atlantis was then successfully launched on June 8, 2007. |
| 19 | 2008-10-20 | Atlantis | STS-125 | Payload | Atlantis was moved back to the VAB to allow time to troubleshoot a problem with the Hubble Space Telescope on orbit. Hardware to correct the problem was added to the STS-125 mission payload. Atlantis was then successfully launched on May 11, 2009. |
| 20 | 2010-12-17 | Discovery | STS-133 | External tank repairs | Discovery rolled off the launch pad after insulating foam and two structural stringers on the external tank cracked during a launch attempt on November 5, 2010. The repair effort lasted two months as engineers beefed up the structural integrity of the structural members in question and replaced the foam that was removed to facilitate those repairs. The mission lifted off on February 24, 2011. The external tank performed flawlessly during fueling and launch. |