NEW YORK — After making the shuttle Atlantis the first orbiter to return to its launch pad in mid-rollback and then weathering tropical storm Ernesto with no problems, NASA will try again Sept. 6 to launch Atlantis and resume assembly of the international space station (ISS).
“There’s no damage that we can find anywhere as of yet,” said NASA Kennedy spokesman George Diller. “We’re still looking at no earlier than [Sept. 6].”
Under the current launch window, Atlantis and its crew of six astronauts could be launched Sept. 6, 7 or 8 on a mission to deliver new solar arrays and a pair of 17.5-ton trusses to the ISS
As Ernesto worked its way up Florida’s Atlantic Coast, shuttle officials decided Aug. 29 to haul Atlantis back to the Vehicle Assembly Building for safe keeping because the storm’s wind speeds were expected to be just barely below the maximum limits allowed for a shuttle-laden launch pad.
But as Atlantis approached the mid-point of its 10-hour trek to the Vehicle Assembly Building, Ernesto weakened to the point that shuttle officials were convinced the orbiter and its launch stack could weather the storm at Pad 39B.
NASA orbiters cannot withstand wind gusts at peak speeds of 70 knots, or about 130 kilometers per hour, at the launch pad.
Ernesto passed over Kennedy Space Center Aug. 30 with peak winds reaching 70 kilometers per hour. By 12:30 a.m. EDT Aug. 31 the area was cleared for normal operations, with the first scheduled shift of workers arriving at 7:00 a.m. EDT , he added.
NASA spokeswoman Katherine Trinidad said Aug. 30 that Atlantis, should it launch Sept. 8, would have to undock from the ISS no later than Sept. 17 to avoid conflicts with the planned ISS crew change. That means the shuttle would lose the option for an extra docked day at the ISS during Atlantis’ STS-115 mission, though extra days are available if the shuttle launches on Sept. 6 or 7, Trinidad said.
Atlantis’ departure would allow a three-day buffer between visiting spacecraft at the ISS to give the station crew time for rest and preparation.
Russia’s Federal Space Agency plans to launch its Soyuz spacecraft Sept. 14, with a fallback date of Sept. 18. NASA ISS managers were in discussions with their Russian counterparts on whether to use that Sept. 18 reserve date, which would put the Soyuz landing of the space station’s current crew — Expedition 13 — before sunrise on Sept. 29.
U.S. and Russian ISS managers hoped to preserve a lighted landing for the Expedition 13 crew as a safety measure, but do have past experience with nighttime Soyuz returns, NASA ISS program manager Michael Sufferdini said in an Aug. 29 teleconference. Night landings are not preferred because they can hamper recovery efforts, which would be critical if the landing astronauts are in distress, Sufferdini said.
“If the shuttle Atlantis lifts off on September 6-8, the Soyuz will be launched on September 18,” Nikolai Sevastyanov, president of the Russian aerospace firm RSC Energia that launches Soyuz and Progress spacecraft, told reporters Aug. 30 in Star City, according to the Russian Interfax news agency.
Current NASA guidelines call for the shuttle to launch under daylight conditions to allow cameras on the ground, in the air and aboard the spacecraft’s launch stack to record the performance of external tank modifications.
The cutoff to launch Atlantis this month under optimum lighting conditions is Sept. 13.
During the upcoming crew swap, a Russian Soyuz spacecraft is expected to launch the station’s Expedition 14 crew and a space tourist towards the ISS Sept. 18, with docking planned for Sept. 20. The outpost’s current Expedition 13 crew would then return to Earth Sept. 29 with the spaceflight participant, U.S. entrepreneur Anousheh Ansari .
The launch of Atlantis, designated NASA’s STS-115 mission, has been delayed several times. A lightning strike and subsequent spacecraft checks at the orbiter’s Pad 39B launch site Aug. 25 prevented launch Aug. 27 and 28 , while Ernesto’s Florida pass scrubbed an Aug. 29 launch attempt.
Atlantis’ flight will mark the first major ISS construction mission since late 2002. It is the third orbiter mission to launch since the 2003 Columbia accident and the first to follow two post-accident test flights — STS-114 in 2005 and last month’s STS-121 — to evaluate shuttle flight safety improvements.