WASHINGTON — NASA's plan to build a space station with the shuttle will be difficult and risky, and could lead to the loss of still another space shuttle orbiter, a National Research Council committee said in a report released today.
The study said that the space agency's plans to build a space station by the mid-1990s "rank as the most ambitious and lengthy task NASA has ever undertaken" and that to be successful it cannot be constructed "on the cheap."
Using the space shuttle to build the station, said the report, would pose about a 60% probability of the loss of another orbiter. It said NASA should prepare for that loss by planning to build still another reusable spacecraft.
"We should expect to lose an orbiter--not necessarily with accompanying loss of life--about once every five to eight years," the report said.
The NRC report said building of spare parts and test hardware could add $200 million to $3.9 billion to the cost of the station, now estimated at $14.6 billion.
In a reply to the report, however, the National Aeronautics and Space Administration said the additional cost estimate in the study "is much too high." The agency put the additional cost for testing and spare parts at only $200 million.
NASA did not endorse the suggestion that a fifth orbiter be built, stating that the agency "remains confident that the current fleet is adequate to support the space station program."
NASA also disagreed that use of the shuttle to build the station would be "risky." NASA said it has recently redesigned the deployment plan for the space station and has "a high degree of confidence that the space station can be successfully deployed with the current shuttle system."
The report, the result of a four-month study commissioned by the White House, the National Security Council and NASA, generally supported NASA's current space station design plan, but besides finding that the station will cost more than NASA claims, said it will require a closer evaluation of the risks involved. It said that to be successful, the program will require a long-term commitment by the government and the American people.