As the threat diminished that Hurricane Dennis would reach the shuttle launch pad, NASA officials decided July 8 to keep Discovery in position for a critical July 13 launch that agency officials are counting on to get the international space station (ISS) program back on track, the first step in U.S. President George W. Bush’s vision for a new era of human space exploration.
Mission managers met July 7 to discuss whether to prepare the shuttle for a potential rollback to the massive, 52-story Vehicle Assembly Building at NASA’s Kennedy Space Center in Cape Canaveral, Fl a. There was some concern that winds could rise past 40 knots, exceeding conditions for a rollback, though NASA officials said it was unlikely.
“The current forecast shows only a slight chance of more than 40 knot winds a ffecting [Kennedy Space Center] on Saturday,” NASA officials reported July 7. By Friday those concerns had eased, and Kennedy Space Center officials said they still hoped to launch Discovery and its seven-astronaut crew at about 19:51 Greenwich Mean Time July 13.
Discovery will be the first space shuttle set to fly since the 2003 loss of the STS-107 astronauts aboard the Columbia orbiter, which broke apart during re-entry after sustaining wing damage from launch debris during liftoff.
The STS-114 mission is the first of two test flights to evaluate shuttle launch system modifications to prevent such damage from reoccurring. Those missions also will be used to check out new tools and procedures for inspecting shuttle orbiters for any potential damage.
The 12-day mission will also be used to deliver fresh supplies, equipment and replacement parts to the two astronauts aboard the space station.
PRIVATE tabstops:<*t(0.000,0,” “,13.500,0,” “,)> For example, during Discovery’s mission two of its astronauts — ISS Expedition commander Sergei Krikalev and flight engineer John Phillips — are scheduled to use digital high-resolution cameras to conduct a comprehensive survey of the protective thermal tiles that line Discovery’s belly.
“They will be doing some test imagery in the next week and charging camera batteries,” said Steven Berenzweig, who trains shuttle and ISS crew members in photography techniques at NASA’s Johnson Space Center in Houston . “We want them to get some practice with their focus and mapping techniques.”
The tile survey images taken by the ISS crew will be relayed back to engineers on Earth, where they will be studied for signs of any damage. They represent only one of two critical photography sessions during Discovery’s STS-114 flight. The other, to be conducted just after launch by the STS-114 crew, will document how Discovery’s modified external tank weathered the spaceflight.
“This is going to be the most photographed shuttle mission that’s ever launched,” veteran astronaut Eileen Collins, commander of Discovery’s STS-114 flight, said in a preflight mission briefing.
Columbia’s thermal protective skin was damaged by foam debris from its external tank during launch, which punctured a wing panel and allowed hot gases to breach the shuttle’s skin during re-entry. The orbiter broke apart over Texas Feb. 1, 2003, killing its crew.
The docking of any space vehicle — manned or otherwise — at the ISS is just cause for crewmembers to grab their cameras. But for STS-114, it is more than a matter of pretty pictures.
“Other images of the orbiter [docking] in the past have been almost more of a public affairs type of thing,” Berenzweig said.
But shuttle engineers will scrutinize the Expedition 11 crew’s images to determine whether Discovery’s thermal protection system is sound enough for the return trip through the Earth’s atmosphere, which currently is scheduled for July 25. If everything checks out the crew can return safely. If extensive damage is found — something flight controllers believe is unlikely — the shuttle crew could seek refuge aboard the space station and await a rescue orbiter.
Krikalev and Phillips are outfitted with Kodak digital cameras, one with a 400-millimeter lens to resolve tile features down to 6.3 centimeters (2.5 inches) , and the other with an 800-millimeter equivalent to provide photographs with a resolution of about 2.5 centimeters.
“The space shuttle will stop directly below the space station, and Sergei and I will be looking out two different windows looking straight down at the space shuttle,” Phillips said in a preflight NASA interview, adding that he expects Discovery’s docking to be a mission highlight. “Unfortunately, it’s not just a sight-seeing kind of thing. We can’t say, ‘Well there’s the shuttle silhouetted against the Great Barrier Reef.’ We’re going to be busy taking exactly the pictures that we’re programmed to take.”
The astronauts will use the 800-millimeter lens to image Discovery’s sensitive tile regions, such as its wheel well doors, while the 400-millimeter camera will document the overall condition of orbiter tiles, NASA officials said.
Krikalev and Phillips have about 93 seconds to sweep their camera lenses across overlapping swatches of Discovery’s tile-covered belly. “Each one of their shots has about 40 to 50 percent overlap from the one before it,” Berenzweig said. “We’re hoping they will get two to three complete mapping passes during the time.”
During Discovery’s docking approach, Collins will park Discovery about 182 meters from the ISS and perform a rendezvous pitch maneuver, which flips the orbiter to present its underside toward the space station, then complete the circle. The entire maneuver takes about nine minutes.
“It’s not an easy task,” Krikalev said of the tile survey during a NASA interview. “It’s very time-critical because the shuttle cannot stay for a long time near, near station.”