Rocket Vertical-Test Plan Could Delay Shuttle Flights

The presidential commission investigating the Challenger space shuttle tragedy will call for a new rocket test program that would make it nearly impossible for the National Aeronautics and Space Administration to resume manned space flights on the schedule laid out in recent days, sources close to the commission said Thursday.

According to those sources, who asked not to be identified, the commission, headed by former Secretary of State William P. Rogers, will call for a number of full-scale tests of the shuttle’s redesigned solid rocket booster, including a vertical test-firing.

Until now, the shuttle boosters have been test-fired only in a horizontal position. The argument for testing in a vertical position is that the booster flies that way. But sources said that a vertical test would require either a new test facility or major modification of an existing test stand, significantly increasing the cost and the time required to get the spacecraft back in operation.

Richard H. Truly, NASA’s space shuttle program director, said Thursday that the space agency has set a target date of July 15, 1987, for launching the next shuttle flight, but he acknowledged that the chief factor determining the schedule will be the tests of the solid rocket booster after it has been redesigned.

Although the official finding of probable cause will not be issued until June 6, investigators long ago concluded that the Jan. 28 loss of the shuttle Challenger and its crew of seven was the result of seal failure in a joint of the shuttle’s right solid rocket. A team of space agency engineers is now working with Morton Thiokol Inc., the rocket manufacturer, to redesign the faulty joint.

Truly, interviewed during a recess in an appearance before the House space science and applications subcommittee, acknowledged that solid-rocket experts are now debating whether a vertical test is necessary.

Already, he said, officials have decided to conduct three and perhaps four horizontal tests of a full-scale solid rocket motor--tests estimated by other sources to cost $12 million to $13 million each.

Of the vertical test issue, he said, “We will do whatever is right. But it is very, very difficult to vertically test a booster that weighs 1.2 million pounds and generates 3.2 million pounds of thrust. We would have to invent a way to do the vertical test.”

The test issue aside, some commission sources said that there is great skepticism over the NASA plan to fly the shuttle again by July, 1987, and a belief that officials are generating pressure on themselves by announcing a new launching target date even before the commission has completed its report.

Appearing with Truly and other NASA officials before the House subcommittee Thursday, Arnold Aldridge, the shuttle program manager at Houston’s Johnson Space Center, said the July target date is already a tight one. As the investigating commission has made its views known informally, he said, NASA has been starting efforts to comply with them.

Plans now call for the first flight to carry a tracking and data relay satellite into orbit. It would be identical to the one carried aboard the Challenger shuttle when it was destroyed in a fireball 10 miles above the Florida coast.

Aside from redesigning the solid rocket booster, officials are in the process of reviewing a long list of shuttle components that are critical to flight safety.

Aldridge said that, so far, engineers have identified 96 “potential safety concerns” in the shuttle system and that 44 of them are significant enough that changes may be required before flights are resumed.

The current plan is for the first launching to be from the Kennedy Space Center. Truly said Thursday that the first launching from Vandenberg Air Force Base is now expected to take place no sooner than the spring of 1988.

Although the report of the presidential commission is still to be issued, NASA officials estimated that it will cost as much as $626 million to restore the remaining three shuttles to flight status, including $250 million for modifications to the booster rocket, $125 million for the orbiter’s main engine, $85 million for its braking and steering system and $46 million for the salvage operation and investigation of the Challenger accident.

The Senate Appropriations Committee on Thursday approved spending $526 million to restore the three remaining shuttles, an important step toward obtaining funds for resuming missions.

While offering no promise of success, Aldridge said a team at Houston is once again reviewing earlier research and the possibility of developing a system that would permit astronauts to bail out or eject themselves from a stricken shuttle.

Ejection seats were used during the first test flights of the shuttle Columbia but were later removed. The decision to fly without an escape system was made because of the cost and the technical difficulty.