Quotes of the Day

Under its current launch schedule, NASA must sweat out up to 17 more nail-biting, foam-flying launches like the Discovery lift-off on Tuesday — including one set for late August or early September — before construction of the International Space Station is completed and the space shuttle is mercifully retired in 2010.

On Wednesday, Discovery's crew spent the day inspecting the craft for any unknown damage caused by small fragments of foam that fell from the fuel tank during launch. They found nothing troubling, which corroborates the video and still pictures of Tuesday's launch. "We do not have any concerns for the orbiter," said shuttle program manager Wayne Hale. Still, aside from delivering 5,000 pounds of supplies to the International Space Station, the entire shuttle mission will center on the safety of the craft — including experiments conducted by the astronauts on ways they could fix the craft's heat shield if damage to it were to make landing risky.

NASA knows it may never be able to completely keep every inch of the shuttle fuel tank's polyurethene foam intact during takeoffs. In this flight, the foam cracked and dislodged before liftoff, all after NASA decided to eliminate 37 pounds of it in a new tank coverage design before Discovery was rolled out to the launchpad. It was a move Hale called the "largest aerodynamic change that we have made to the space shuttle since it first flew."

Given the shuttle's recent mishaps, even a close call with Discovery — such as a shuttle emergency landing back to Florida or at alternate landing sites in Spain or France — would likely be enough to shut down the program now, rather than in 2010. It would also make it more difficult to push on to the Moon and Mars, let alone finish the Space Station. "If we fail to complete the space station, it will adversely affect our credibility with future international partners," says NASA administrator Michael Griffin. Space modules from Japan and the European Union are already at the Kennedy Space Center, waiting for the space shuttle to carry the sophisticated, multi-billion dollar laboratories to the Space Station.

NASA is hoping to shave off the last two of its planned 17 upcoming shuttle flights by encouraging private industry to develop a commercial short-hop space vehicle to ferry astronauts and supplies to and from the space station. Then, to replace the shuttle, NASA is planning a new-generation, Apollo-style capsule capable of going on to the moon. Foam should not be an issue on the next-generation space ship because the crew capsule will sit atop the rocket rather than essentially hug the rockets as does the shuttle. If foam insulation is used, any debris will fall down and away from the capsule. The capsule also will come capped with an escape rocket that can blast the crew compartment away to safety in the event of a launch mishap.

NASA is expected early this fall to award a contract for the new capsule to either Lockheed Martin or a Northrup Grumman-Boeing team. But because of budget constraints, the new capsule is not expected to be ready until 2014.

• Stefano Coledan and Barbara Liston
• The foam problems apparently caused no damage to Discovery. But from now on, each launch is likely to be a nail biter