NEW YOrK — A team of engineers is taking a meticulous look at the hail-damaged external fuel tank on NASA’s Space Shuttle Atlantis to determine how best to repair its weather-beaten surface for a planned April launch to the international space station (ISS).
“We’re kind of working our way down the tank to assess it,” Harry Wadsworth, a spokesperson for shuttle fuel tank manufacturer Lockheed Martin, said in a March 8 interview. “We should have a go-forward plan early next week to take to the space shuttle program.”
A freak thunderstorm centered right over NASA’s Pad 39 launch complex at the Kennedy Space Center (KSC) in Cape Canaveral, Fl a., peppered Atlantis’ fuel tank with golf-ball-sized hail Feb. 26, covering the tank’s foam insulation with thousands of gouges. Atlantis had been slated to launch its six-astronaut STS-117 crew towards the international space station about March 15 . Launch is now tentatively scheduled to occur in late April.
Wadsworth said a team of about six tank specialists was headed to NASA’s Kennedy Space Center from the Michoud Assembly Facility near New Orleans where shuttle fuel tanks are manufactured.
Some foam sanding or blending to address extremely minor damage might be performed , but the primary goal is to survey Atlantis’ fuel tank and draw up a comprehensive repair plan, Wadsworth said.
NASA shuttle workers also are examining some minor dings to 27 protective heat-resistant tiles on Atlantis’ underside. Launch officials have said ricocheting hail may have circumvented the shroud-like Rotating Service Structure at Atlantis’ launch pad, which protect orbiters from weather, to cause the dings.
It was the 17th time in the 26-year-old shuttle program that one of the vehicles had to be moved back to the Vehicle Assembly Building from the launch pad.
Damage to fuel tank foam insulation and the insulating tiles has been a prime concern for NASA since 2003, when a chunk of foam shook loose during the launch of the shuttle Columbia and struck the orbiter’s left wing. The resulting damage to the Columbia’s heat shield allowed fiery gases to penetrate Columbia during re-entry, breaking up the craft and killing its crew of seven astronauts.
NASA has since redesigned shuttle fuel tanks to reduce the amount of foam shed during liftoff and developed in-orbit inspection procedures, as well as some limited repair techniques, to address the problem in orbit if required. But ensuring a tank is fit to fly in the first place is imperative, NASA officials said.
“What the program has cautioned everyone is, ‘Let’s let the team go off and do their work,'” NASA Kennedy Space Center spokeswoman Jessica Rye said in a telephone interview. “They’ve got a lot of inspections to do. We want a full story on what the tank team feels needs to be done.”
Commanded by veteran shuttle flyer Rick Sturckow, Atlantis’ STS-117 astronaut crew is slated to haul a 17.5-ton addition to the space station’s core framework and two starboard solar arrays.
The mission is scheduled to be the first of what NASA officials still hope will be as many as five ISS construction flights in 2007, the most ambitious flight schedule in five years.
The STS-117 crew’s 11-day mission to the ISS includes three spacewalks to deliver and install the new Starboard 3/Starboard 4 (S3/S4) truss segment and deploy its wing-like solar arrays.
“I’m nervous about retracting solar arrays,” Mike Suffredini, NASA’s ISS program manager, said of the upcoming mission. “I think that will be probably one of those things we will spend probably a little more time on than we think we will .”
The upcoming shuttle flight could run two days longer than planned and include a fourth spacewalk to handle any unexpected glitches in either the Port 6 solar wing retraction or the Starboard 3/Starboard 4 (S3/S4) truss delivery or deployment, Suffredini said.
Atlantis’ STS-117 mission will mark NASA’s third flight dedicated solely to ISS construction since the 2003 Columbia accident. It is the first of 13 planned orbiter missions, with three extras possible to haul spare parts and cargo, to complete ISS assembly by 2010, when NASA plans to retire its shuttle fleet to make way for the Orion Crew Exploration Vehicle and its Ares rockets.
Joining Sturckow on the STS-117 mission are Atlantis shuttle pilot Lee Archambault and mission specialists James Reilly, Steven Swanson, Patrick Forrester and Danny Olivas. Their spaceflight will help prime the ISS to support new modules and international laboratories slated for launch later this year.
“We have a tremendous amount of work that we’re going to be doing for the international space station program,” said NASA shuttle program manager Wayne Hale, who called NASA’s next year of orbiter missions “extremely ambitious.”
Four more shuttle missions dedicated to continuing construction of ISS have been scheduled for 2007: STS-118 on June 28; STS-120 on Aug. 26; STS-122, sometime this fall; and STS-123 on Dec. 8.
In addition to delivering the new S3/S4 solar arrays, NASA shuttles are due to ferry a new starboard spacer section of the station’s main truss, the Node 2 hub for future modules, and the European Space Agency’s Columbus laboratory later this fall to be followed by the first part of Japan Aerospace Exploration Agency’s Kibo laboratory.
In between those shuttle flights some four unmanned Russian cargo ships, the first automated European resupply vehicle and two Soyuz spacecraft with new ISS crews will visit the orbital laboratory, station managers said.
“We’ve spent many, many years preparing for this and training for this,” Suffredini said. “The partner elements are ready to go fly.”
But Hale stressed that the planned launch schedule will always be susceptible to delays, especially those due to safety. “We don’t want to let schedule drive us to do something dumb.”
Three shuttle missions were originally slated to launch Feb. 22, June 11 and Aug. 9, respectively, but were pushed back to accommodate shuttle processing needs, as well as plans for upcoming ISS astronaut spacewalks, crew rotations and automated cargo shipments.
NASA’s STS-118 mission will add another truss segment and a spare parts storage platform to the ISS, paving the way for Atlantis’ STS-120 mission to install the U.S.-built hub that will link future laboratories.
STS-122 aboard Discovery, will deliver the European Space Agency’s Columbus laboratory to the ISS. Endeavour is expected to launch its STS-123 mission in December carrying the logistics module for Japan’s Kibo laboratory and Canada’s Dextre robotic arm attachment.
Meanwhile, NASA has chosen a substitute spacecraft ground communicator for the STS-117 mission to replace astronaut Lisa Nowak, who is facing criminal charges stemming from a highly publicized incident in Florida.
Cathy Koerner, lead shuttle flight director for NASA’s STS-117 mission aboard the Atlantis orbiter, said astronaut Terry Virts will take Nowak’s position as lead spacecraft communicator — or Capcom — during the upcoming mission.
“Terry was my Capcom during [STS-115], and so he’s familiar not only to me but to this mission and its content and also to the rest of the flight control team,” Koerner said of Virts, referring to NASA’s September 2006 shuttle mission in which astronauts performed similar tasks to those set for STS-117.
NASA placed Nowak on a 30-day leave after she was charged with attempted murder, attempted kidnapping and other counts stemming from a confrontation with a woman whom police said the astronaut believed to be a romantic rival for the affections of a space shuttle pilot.
Nowak, an active duty Navy officer detailed to NASA, was subsequently relieved of her astronaut duties and reassigned to the Navy.
Virts also served as a spacecraft communicator for one of three ISS Mission Control shifts during NASA’s STS-116 shuttle mission in December 2006.
Capcom astronauts serve as the voice of Mission Control to astronauts in orbit, with separate positions in place for both the space shuttle and the ISS. Nowak was training to serve as lead STS-117 shuttle Capcom before NASA placed her on leave.