STS-121 Shuttle Commander Confident in July Launch Target
STS-121 commander Steven Lindsey undergoes emergency egress training session in the Space Vehicle Mockup Facility at the Johnson Space Center.
Credit: NASA.

As NASA celebrated the 25th anniversary of its first shuttle flight Wednesday, the commander of the space agency's next orbiter to fly said he is confident his crew will launch in July.

Veteran shuttle astronaut Steven Lindsey, commander of the STS-121 spaceflight aboard the Discovery orbiter, told reporters that while more external tank testing is still needed, he remains optimistic that his mission will fly this summer.

"We're doing some wind tunnel testing and we've done some redesign of the tank," Lindsey said in video interviews. "I'm pretty optimistic that we're going to make July."

Second test flight

NASA's STS-121 mission is the agency's second test flight following the 2003 loss of Columbia and its seven-astronaut crew.

NASA launched its Discovery orbiter on the STS-114 return to flight mission in July 2005, but later delayed the STS-121 spaceflight pending debris concerns over loose chunks of shuttle fuel tank foam seen in that ascent. A similar foam-shedding problem doomed Columbia's 2003 STS-107 mission when a piece of loose foam punched through the orbiter's heat shield at launch, leaving it vulnerable to the high temperatures of reentry.

NASA has since opted to remove a protective foam ramp - which shed the large foam pieces in the STS-114 launch - from shuttle fuel tanks, though additional wind tests are required to ensure the fix won't compromise tank integrity during flight.  

"We obviously will not launch until all those issues are resolved," Lindsey said. "But I'm confident that we're getting there. Eventually we just have to go fly and test it to see if it works. It's a flight test mission."

From a training perspective, Lindsey's STS-121 crew is just about ready for flight, the shuttle commander said.

NASA plans to launch Discovery's STS-121 mission between July 1 and July 19 on a 13-day flight to the International Space Station (ISS).

In addition to testing shuttle repair and flight safety methods, the crew is expected to perform three spacewalks and deliver European Space Agency astronaut Thomas Reiter to the ISS as the outpost's third crewmember. The space station's current two-astronaut Expedition 13 crew arrived on April 1.

If all goes well, two additional shuttle crews could launch toward the space station in August and December, NASA has said.

Shuttle at 25

Despite the shuttle program's extended downtime and flight delays since the Columbia accident and, more recently, the STS-114 mission, Lindsey maintains a deep affection for NASA's space shuttles.

"Even now, 25 years later as I'm flying it, I'm still amazed," Lindsey said, adding that he was a college junior at the U.S. Air Force Academy when Columbia launched its first flight on April 12, 1981. "We can do just about anything you can imagine with the shuttle."

A veteran of three shuttle flights, Lindsey first mission was 1997's STS-87 spaceflight aboard Columbia.

Lindsey said he'll be sad to see NASA retire its three remaining orbiters - Discovery, Atlantis and Endeavour - in 2010 to make way for its capsule-based Crew Exploration Vehicle, but that he doesn't believe the concept of a reusable winged spacecraft is gone for good.

"I think we will see a shuttle-type vehicle in the future, but not in the near future," Lindsey said. "I think the concept is still good, but this technology needs to advance just a little bit more before we do this a little more routinely."