Before NASA can fly space shuttles again, it will likely have to give astronauts a way to repair damaged heat-protective tiles in orbit, restrict future flights to the international space station and replace its outdated ground computers, Columbia investigators said Tuesday.
Limiting flights only to the space station could allow astronauts to carefully inspect the orbiter for damage during each flight and then make critical repairs to any damaged tiles before returning to Earth, said Steven B. Wallace, a member of the investigative board.
Although investigators are still looking into what caused the loss of Columbia on Feb. 1, they believe the accident involved a problem with the craft's thermal protection system and are already deciding about the steps that NASA must take before any resumption of launches, Wallace said in an interview.
Among other recommendations, Wallace said NASA will likely need to overhaul its disco-era computer system at the Kennedy Space Center, which was developed and built during the 1970s and is now so old that few engineers know how to fix it. A modernization program was canceled last summer by NASA chief Sean O'Keefe.
The recommendations would cost hundreds of millions of dollars and disrupt NASA's long-term plans.
The space agency, for example, plans to fly to the Hubble Space Telescope within three years, where a shuttle crew would make needed repairs and improvements. NASA also has plans for future science missions that would not fly as high as the space station. Now, those missions may have to be scrapped or delayed indefinitely.
In a worst-case scenario, NASA officials have said, it could take up to two years before the shuttles resume their flights.
Wallace is among the investigators who will propose the recommendations that would allow NASA to begin flying shuttle missions again and determine broader changes that need to be made at the space agency.
"We're trying to make this a systemwide thing," said Wallace, one of the few civilians on the investigative board. He is also the director of the Federal Aviation Administration's Office of Accident Investigation.
Technically, it will be NASA's decision whether to adopt the investigative board's suggested reforms. But O'Keefe made it clear Tuesday that the agency will abide by the recommendations.
"We'll be guided by those findings," he told reporters in Washington.
Meanwhile, the Columbia Accident Investigation Board described a broad range of findings at a news conference in Houston, though members said they are still trying to determine the direct cause of the accident and understand all the evidence of trouble during the final moments of the flight.
Investigators believe that the thermal protection system failed, possibly after foam insulation fell from an external fuel tank and struck Columbia shortly after its Jan. 16 liftoff. More than 20,000 tiles, most smaller than a pizza box, cover the bulk of the shuttle and are designed to withstand the violent vibrations and heat of reentering the Earth's atmosphere.
NASA officials have said that even after engineers discovered the foam insulation accident while reviewing film of the launch, the agency had no way to assess damage while the shuttle was in orbit. And even if they had determined that the shuttle was fatally wounded, the astronauts were helpless to perform repairs, NASA officials said.
NASA has already begun studying whether astronauts who dock at the international space station can take advantage of its $1-billion robotic arm for inspections. NASA officials hope to devise a way for astronauts to use the 57.7-foot, 3,000-pound arm as a platform to perform repairs while spacewalking.
At the Johnson Space Center in Houston, NASA spokesman James Hartsfield said engineers studying the issue met for the first time last week and have not determined whether it will be possible. He said engineers don't know how long the study will take. "They are only a couple days into it," he said.
The ability to repair damaged tiles in space would be crucial to getting the shuttle back in the air, said Paul Czysz, professor emeritus of aerospace and mechanical engineering at Saint Louis University and a veteran NASA consultant.
NASA will also have to make sure the foam insulation sticks better to the external tanks, he added.
The space station could be outfitted with a tile repair laboratory, but Czysz said a more difficult task will be providing astronauts with the ability to repair the leading edge of the wing, an area constructed of a tough reinforced carbon material. The edge of the wing is attached to the shuttle with fasteners that are inside the wing, so it might be more difficult to repair than the rest of the craft, he said.
Columbia's 16-day mission was dedicated to more than 80 science experiments and did not dock with the space station. But it was the exception -- almost every shuttle is now sent to the space station to ferry personnel, supplies and construction materials.
If the shuttle were to arrive at the space station with such major damage that it could not be repaired, the crew could stay there until they could be rescued either with a Russian spacecraft or another shuttle. The damaged shuttle could be returned to Earth unmanned, using on-board computers and controllers on the ground.
While the life of the crew is the most pressing safety issue, it is not the only consideration. With just three shuttles remaining, NASA no longer has a margin for losing another orbiter if it wants to continue the human space flight program, Czysz said. Because one orbiter is almost always being refurbished, NASA will now have only two operational orbiters at any given time -- the bare minimum, Czysz said.
A more contentious recommendation could be directed at the 1970s-era computer system used to prepare and launch space shuttles at the Kennedy Space Center.
Though Wallace was quick to point out that it still works, the system was developed with mainframe computers built by a manufacturer that is no longer in business. New desktop computers have 2,000 times the memory of the NASA launch system, which runs on computer language that is no longer in use.
Last summer, after $273 million had been spent planning a replacement of the system, O'Keefe, the NASA administrator, canceled the program because of cost overruns. Investigators say it could cost another $400 million to overhaul the system, but Wallace said it could be a necessary step.
Wallace said the board does not believe the dated computer system is "causally connected" to the Columbia disaster.
But, like investigators did after the 1986 explosion of the space shuttle Challenger, the Columbia board expects to recommend a host of changes to programs that were not directly related to the accident.
NASA engineers have "very openly and not even very critically" told investigators about difficulties they encounter because of the aging computer system, Wallace said.
One of the most surprising revelations exposed by the Columbia accident has been the contrast between sophisticated, $2-billion space shuttles and the timeworn technology used to operate them.
For instance, the space shuttle is outfitted with cameras that capture stunning, high-resolution images of launches. But the cameras still use film, which even many amateur photographers have cast aside in recent years.
"That's great," Wallace said, "if you recover the film."
In the case of Columbia, the film appears to have been destroyed. Those images could have been critical to the investigation, because they likely included footage of foam insulation falling from the external tank and striking the shuttle's left wing area, Wallace said.
With a technology overhaul, Wallace said, NASA would be able to ship those images directly to Mission Control computers.
Hartsfield, the NASA spokesman, declined to comment on recommendations the board might offer.
Times staff writer Nick Anderson contributed to this report.