Herrington shuttle mission on hold

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CAPE CANAVERAL, Fla. ? Astronaut John Herrington will be the first registered American Indian, Chickasaw, to fly in space, but his historic mission is going to be delayed, possibly until November.

Herrington's space shuttle mission is on hold as NASA engineers try to resolve problems with plumbing on the shuttle fleet and schedulers juggle an array of factors, ranging from safety rules for the International Space Station to an annual meteor shower. NASA has grounded all of the shuttles due to a perplexing problem involving the flowliners, metal channels that ensure that the liquid hydrogen fuel flows smoothly to the shuttle's engines.

Herrington's mission has already been delayed once. The STS-113 mission was originally scheduled for launch to the International Space Station Alpha in September but was pushed back to Oct. 6 due to changes aboard the space station.

The flowliner problem emerged recently. Shuttle program manager Ron Dittemore said, "We observed a visual crack on the flowliner on [shuttle] Atlantis. As a result of that one finding we start to inspect the other shuttles." The flowliners are small channels in the plumbing to the shuttle's main engines.

Dittemore said "Each vehicle we looked at we found cracks. It is not age related ? whether I've flown the vehicle 16 times or 30 times the data appears to show the cracks are present and are relatively the same size. It's clear we've been flying with these cracks for some period of time."

Dittemore said he is optimistic that the problem will be solved soon and the shuttles could be flying by fall. He said, "The most realistic manifest I have in front of me is early September to October."

NASA managers have not decided whether or not to change the order of the missions but they say Herrington's flight has the highest priority. Endeavor, Herrington's flight, will carry a truss segment to the Space Station and bring home Alpha's long-duration crew.

Space station long-duration crews are launched on planned four-month stays, with the possibility that technical issues like shuttle delays will cause them to be extended up to an additional two months. Beyond that point NASA and Russia would have to decide on a case-by-case basis whether or not to authorize additional extensions based on the health of the crew and their willingness to serve additional time in space.

Since Herrington's flight is the mission that will take home the Expedition 5 crew of Valeri Korzun, Sergei Treschev and Peggy Whitson, NASA wants to keep it as close to the planned schedule as possible.

The other shuttle missions have lower priority. Columbia is flying a non-space station research mission. Atlantis is flying a piece of the space station's truss to Alpha. Discovery is currently undergoing its "100-million-mile checkup" and is not scheduled to fly another mission for at least a year.

Compounding the issue is the late return of Endeavor from its previous flight. The STS-111 Endeavor mission was scheduled for launch on May 30, with a return to the Kennedy Space Center on June 11. But weather and technical problems delayed the launch until June 5. Weather also delayed the landing, forcing managers to order Endeavor to land at the alternate landing site in California. Weather even delayed Endeavor's cross-country ferry flight from California to Florida. Endeavor finally arrived in Florida on June 29. That was 18 days later than if it had launched on the first try and landed in Florida on schedule. Normally managers pencil in a couple of weeks of spare time between missions to allow for unexpected delays but Endeavor's multiple delays eliminated that margin.

Assuming engineers can find a quick fix to the flowliner problem, the shuttle fleet could be flying by mid Sept., with minimal delays to the missions. But there is another problem, ? avoiding certain blackout dates.

Russia provides the Soyuz "lifeboat" for Alpha. The three-person spacecraft provides a way for the long-duration crews to "abandon ship" in the event of a major problem like a fire or depressurization. A Soyuz is rated for about six months in space and the current Soyuz will reach that limit in mid-October. So every six months a Russian-led three-person crew flies to the space station in a fresh Soyuz and returns to Earth in the old Soyuz. To avoid interfering with that Soyuz flight, Herrington's mission cannot launch between Oct. 11 and Nov. 2.

Another blackout period involves the annual Leonids meteor shower. The Leonids are the remains of a broken-up comet which intersect the Earth's orbit around the Sun on Nov. 17 each year, producing spectacular meteor showers. Because of the extremely high speed of the particles, NASA does not want to have a shuttle in orbit during the Leonids. An impact with tiny piece of high-speed comet dust could do as much damage as running in to a brick wall.

The space station is safe because it has far heavier shielding, since it stays in space continuously. Shuttle flight rules dictate that a mission planned for launch early November has to land before the Leonids or wait until after the danger is over. In the case of STS-113 the acceptable launch period will come between Nov. 2 to 6 or after Nov. 18, after the Leonids have passed the Earth's orbit.

NASA hopes to have a better idea of what is required to repair the flowliners, if anything, by the end of July. Once it makes a decision on the repairs, it can decide whether or not to change the order of the missions and when they will be rescheduled.