The vice chairman of the NASA task force investigating the Jan. 28 Challenger accident today expressed "confidence" that the causes of the tragedy would be determined within the next 30 days.

"Based on the progress I've seen, it's doable," said James R. Thompson Jr., formerly an associate director at NASA's Marshall Space Flight Center in Huntsville, Ala. Thompson said the cause of the accident could be determined even without recovering fragments of the suspect right solid rocket booster that now lie off the Florida coast. Efforts to retrieve that debris from the ocean floor continue.

The National Aeronautics and Space Administration task force, chaired by astronaut Richard Truly, is pushing to meet an April 18 deadline for the presidential commission to publish a preliminary final report on what caused the Challenger to explode shortly after takeoff on Jan. 28.

Thompson declined to discuss any of the accident scenarios now under consideration by the task force, saying that the commission would probably discuss them later this week. "I believe we will identify with high confidence the problem area," he said in a news conference here. "The exact sequence of events? I'm reasonably optimistic that we'll nail it."

Thompson repeatedly stressed that NASA's task force is working harmoniously with the presidential commission. "There's only one investigation, and that's being conducted by the commission -- all our activities are in support of them . . . . we are feeding them data."

Similarly, he downplayed concerns that the commission investigation was disrupting NASA. "I believe the commission is doing a good job. I don't have any quarrel with them," he said. "You can never have too many eyes" looking at the problem.

Some NASA officials -- notably Kennedy Space Center director Richard Smith -- have sharply criticized the tone and manner of the commission's investigation.

Thompson also dismissed the newly retrieved shuttle flight recorders and onboard computers as keys to unlocking the Challenger puzzle. While the devices may provide information on the last seconds of the shuttle flight, he said, they are unlikely to help pinpoint the origins of the explosion.

"I don't believe they're going to give us information that will lead us to the cause," he said. "The problem is clearly in the propulsion area."

In Washington today, Barbara Morgan, backup to teacher-in-space Christa McAuliffe, said that she and McAuliffe were told during training of the risks connected with flying on the space shuttle, and Morgan said she "can't wait" for her chance to go on a mission.

She made her comments following a news conference at which she announced the formation of a Teacher in Space Foundation to further the goals of McAuliffe, killed along with the six other crew members in the explosion of the space shuttle Challenger.

"We definitely knew the risks," Morgan said, adding that Francis R. (Dick) Scobee, commander of Flight 51L, which exploded Jan. 28, had told the teachers there would be a catastrophic accident "someday . . . . We knew we were sitting on a very large rocket filled with explosives."

Morgan said she does not know when a shuttle mission will be made available to her.

Astronaut Sally Ride, a member of the presidential commission investigating the accident, said on March 6 that the risks might not have been fully explained to McAuliffe and that NASA "may have been misleading people into thinking this is a routine operation." Other NASA astronauts have expressed anger that they were allowed to fly missions without being informed of serious concerns among engineers about the solid rocket booster seals, one of which is the leading suspect as the cause of the Challenger accident.

Asked about these events, Morgan said she has as much confidence in NASA as she did before the accident and does not feel at all "used" by the agency. "Christa was going on the shuttle for education. I would be going for education. We're very committed."

She said the period of grief following the accident was "very hard . . . . I miss my friends very much."

The goal of the new foundation, Morgan said, is to "foster the pioneer space-age spirit in American education." Based in Washington, it plans to present 10 annual awards to innovative teachers, hold an annual space education conference in conjunction with a shuttle launch, provide classroom lessons associated with the shuttle program, operate a national speakers' bureau and publish a bimonthly journal.

The nine surviving teacher-finalists, present at the briefing, worked together to design the foundation, she said.

"We will honor Christa's dream and make it live," Morgan, a teacher from McCall, Idaho, said.