No "Immediate Easy Fixes," Says NASA

By Senior Correspondent Kevin R.C. O'Brien

On Friday, the government's traditional day for slipping bad news to the weekend-bound public, NASA pulled the plug on STS-121's scheduled launch date of 22 September and allowed that, perhaps, a November launch would go on as scheduled. Perhaps not.

After new, environmentally-safe CFC-free insulation caused the loss of the orbiter Columbia and its crew of seven, NASA spent two years and $1.4 billion analyzing the accident, making presentations, and changing hundreds of parts and hundreds of procedures for thousands of workers -- but stuck with the new insulation. That decision bore consequences, when the flight of Discovery was also threatened by chunks of loose insulation last month.

To put it another way, fifty-six times the cost of Rutan and Allen's SpaceShipOne program was spent -- as it turns out, not to address the problem.

After Discovery's recent return to flight, in which the same insulation flaked off again but fortunately caused no serious damage, NASA is back in the PowerPoints-and-blame game with a vengeance.

They were expecting some flaking, but no pieces big enough to threaten the orbiter. Instead, the external tank lost hazardous pieces in five places, mostly places where necessary attachment points and fittings disturb the smooth regularity of the tank.

Some of these are new, never-seen-before problem areas; others, NASA thought they fixed with redesign during the long night between Columbia's failed reentry and Discovery's flawed launch. Both were unanticipated and are unwelcome to NASA officials, who thought they had beaten the insulation problem.

"We didn't find any immediate easy fixes," NASA's Bill Gerstenmaier admitted. The most probable approach at this point, is that NASA will redesign those five areas of the external tank, and the way that insulation attaches to them. The detail engineering design and substantiation of the new fittings and processes, and the manufacture of new parts, can't possibly be done in time for a September 22nd launch of Atlantis, hence the cancellation. Indeed, it will be quite a feat to complete this task in time for the November launch, which remains in pencil at this time.

Atlantis is already mated to its stack of tank and boosters in Cape Canaveral's Vehicle Assembly Building. Workers will most likely have to de-mate the spacecraft components in order to install any improvements developed in response to the problems seen in Discovery's flight.

NASA has ruled out any return to the pre-Columbian, safer, but polluting, insulation. When the next orbiter flies, it will have the same flaky (literally, as in "flaking off") foam insulation. "Even the next time we fly the tank, I would expect to see a little bit of foam loss somewhere," NASA's Bill Gerstenmaier admitted to a media teleconference. As long as the flakes don't have enough mass to cause serious damage to the orbiter, there's no harm in them.

It only sounds on the surface, though, like NASA has an easy task. One is reminded of Napoleon's saying of war: "All the important things are simple. But all the simple things are very hard." The practical trick is, managing foam loss so that the parts lost do not have enough mass or motion relative to the shuttle to damage the system. When aerodynamic forces tear a piece of insulation off the shuttle, its large area relative to its light weight decelerate it abruptly, creating a delta between its velocity and that of the accelerating shuttle. That velocity delta can lead to damaging impact forces if the foam is struck by the lightweight structure of the orbiter.

The piece of foam that destroyed Columbia and killed seven astronauts weighed 1.67 pounds, according to NASA calculations. The largest piece seen on Discovery's tank cameras (one of the $1.4 billion in post-Columbia improvements) was estimated to weigh 0.9 pounds, and came from an area that was never previously thought to be a foam-shedding problem.

Another headache for NASA is the relatively limited launch windows available for the orbits required to reach the agency's other struggling manned project, the International Space Station. The Atlantis STS-121 mission is planned to bring the crew in the ISS up to three for the first time since the grounding of the shuttle fleet after Columbia's February, 2003 crash. Since then, the station's been prudently limited to the two pax that a Soyuz capsule can safely accommodate. Discovery carried some of the supplies to support the third stationaut, and even more supplies will come in Atlantis.

Just as much as that third man or woman, the materiel supposed to come up in the ESA Leonardo logistics module aboard Atlantis is critical to resumption of creative, rather than caretaker, work on the ISS. If Atlantis makes the November flight, Space Station construction can resume in March, 2006.

Meanwhile, the shuttle orbiter Discovery has been gone over with minute attention to detail and is being prepared (photo) to be mated to the specially modified Boeing 747 that brings the shuttle back to Canaveral when it has to, like any other glider beset by unfavorable climactic conditions, "land out."

To some extent the delays are a matter of politics with a small "p." As a public agency, NASA is very deeply dependent on public support, and NASA brass are keenly aware of this. The fundamental risks of the Shuttle remain pretty much the same whether the next launch happens in September, November, or 2007, but NASA can't stand the political risk of not launching again, relatively soon; it can't stand the political risk of not doing anything and then having another mishap, either.

NASA's media strategy, as far as it went, worked. Google News won't find you a single article on the Friday press call, although the space specialty media, and British techie page The Register, carried stories on it.

FMI: www.nasa.gov