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STS-115 Milestone Gallery:
Rollback reversed: Shuttle returns to pad
August 29, 2006 — After deciding to roll space shuttle Atlantis from the launch pad to its assembly building as a shelter from an oncoming tropical storm, NASA reversed its direction, literally, sending the vehicle back to the pad.
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More photographs below.
Atlantis was midway through its 4.5 mile trek from Pad 39B when its crawler transporter was halted and then restarted in reverse. According to NASA, the round trip journey would take approximately 10 hours to complete.
The shuttle departed the pad at 9:04 a.m. CDT.
The unprecedented decision to rollback and then rollout again, came as NASA refined its comfort with Tropical Storm Ernesto, which is currently expected to approach Kennedy Space Center on Wednesday. The storm has weakened though and NASA believes the shuttle will be safe behind its steel service structure on the launch pad.
"There's no trepidation in my mind at all about the decision," said NASA Launch Director Mike Leinbach during a press briefing. "This is the right way to go."
Earlier this week, Leinbach had said that in the case of a rollback, it would take eight days from the point Atlantis arrived back on the pad to prepare it to launch the crew of STS-115 and their space station truss assembly payload.
The current launch window, which opened on August 27 and extends through September 7, is limited by NASA flight constraints and Russia's Soyuz launch schedule.
In order to evaluate design changes made to the shuttle's external tank, NASA has set rules that require sufficient sunlight to capture imagery of the tank and orbiter as they launch.
If lighting was the only concern, NASA would have until September 13 to launch Atlantis. Complicating matters is lighting of a different type.
Russia is planning to launch its own crewed spacecraft, Soyuz, on September 14. The mission is scheduled to take the next crew to the international space station (as well as an American tourist) and then return the previous ISS expedition to Earth. To facilitate their recovery, the Russians want them to land at dawn, when the steppes of Kazakhstan will be in daylight.
If the Soyuz TMA-9 launch is delayed, it would result in an early morning touchdown, making it potentially difficult for recovery helicopters to promptly locate the crew.
NASA set its own limit on the STS-115 window to allow enough of a buffer between shuttle and Soyuz operations at the space station.
Then lightning struck.
While preparing to launch Atlantis last Friday, a 100,000 amp bolt of lighting was registered striking the pad. The surge created a concern that the shuttle's systems might have been affected. By the time NASA resolved that the vehicle was healthy, then-Hurricane Ernesto's path made rollback preparations necessary.
NASA is now targeting September 6-7 for its next launch attempts, though that is contingent on when preparations can resume at the pad after the tropical storm leaves the area.
If they cannot launch during the current window, NASA's next opportunity is in late October. The space agency is also in discussions with their Russian counterparts about delaying their Soyuz launch just long enough to provide a few extra days in September.
Had Atlantis' trip today not been reversed, it would have been the 17th rollback in shuttle history and the fifth as a result of a tropical storm or hurricane.
When it launches, the STS-115 mission will resume the assembly of the space station with the delivery of another truss and pair of solar arrays. Its six person crew, which has been in training for this mission since before the loss of shuttle Columbia in 2003, will conduct four spacewalks during their 11 days in space.
Commander Brent Jett, pilot Chris Ferguson and mission specialists Joe Tanner, Dan Burbank, Heide Stefanyshyn Piper and Canadian astronaut Steve MacLean returned to Johnson Space Center Tuesday morning. The crew will return to Kennedy after a new launch date is confirmed.
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