The commander of the space shuttle that landed Tuesday is offering a response to critics of the shuttle program like Iowa Senator Tom Harkin. In late July, Harkin said it was time for NASA to scuttle the space shuttle program because of “enduring problems.” Eileen Collins, the commander of shuttle Discovery, acknowledges there are problems, but nothing that should doom the program. “The flight control system worked perfectly,” she says. “We felt very safe.” Harkin said July 28th that he’s never been a “big fan” of the shuttle. “I always thought it was sort of the brainchild of pilots who wanted something to fly but it never really had a real purpose,” Harkin said. “I think we’ve wasted a lot of money on this shuttle and I don’t know that it’s ever really gotten us anything.” NASA has grounded future shuttle launches until the problem of flaking foam falling from the fuel tank — and potentially damaging the outside tiles on the shuttle — is fixed. Collins, the commander of the latest shuttle mission, says the shuttle program must continue in order to meet obligations to the International Space Station through 2010, but she acknowledges the shuttle fleet is aging. “Airplanes age just like people age,” she says. “I think the work that’s been done on the shuttle program has been fantastic.” “Some people say we should stop flying the shuttle because we had an accident. Frankly, we had two accidents, but we are people who believe in this mission and we are going to continue it,” Collins says. Harkin, though, would be happy to see this be the last shuttle mission. “It’s time to move out of low-Earth orbit and shuttles and move into something else,” according to Harkin. That means unmanned flights, and that’s not something Collins believes in. “This mission is very important, exploring space and making life on earth better for all of us,” she says. “There’s a whole cadre of astronauts…who are very, very anxious to go up there.”