A Navy salvage ship has retrieved a part of the space shuttle Challenger's key right-hand booster joint with a 2-foot hole burned through it, the first direct physical evidence that a leak in that joint caused the Jan. 28 disaster.

The 2-ton section of the cylindrical metal rocket case was recovered Sunday off Cape Canaveral and includes part of the upper section of the joint that failed. A Navy spokesman said the part has a 1-by-2 foot hole burned through it in the position where photographs and videotapes show hot gases spewing from the booster just before the shuttle exploded.

It supports more concretely the conclusion that a seal in the joint failed, sending the booster crashing into Challenger's external tank and breaking up the orbiter, killing its crew of seven. All other evidence had pointed to such a failure but until Sunday no parts of the joint in the area of the leak had been recovered.

Recovery of booster pieces from the joint area has been the top priority of the Navy salvage effort. A source familiar with the investigation said yesterday that this debris "is consistent with all the evidence analyzed to date."

The boosters, 180 feet tall and 12 feet in diameter, are made of four sections. The joint between the lowest two sections failed. The joint is supposed to be made airtight with an array of rubber O-rings and putty, both of which are suspected of having failed to adequately seal because of cold and other factors.

The joints had a five-year history of sealing problems, which the National Aeronautics and Space Administration had failed to correct.

The presidential commission investigating the Challenger accident released a statement yesterday confirming the retrieval of a piece of "critical interest." Commission member and MIT professor Eugene Covert was dispatched to Cape Canaveral to examine it.

Meanwhile in Norfolk, divers involved in the orbiter recovery effort said the shuttle's crew compartment was reduced to an unrecognizable clot of metal and wires.

Officers and crew of the USS Preserver, in their first public comments, declined to describe the condition of the astronauts' remains beyond saying that they were not readily recognizable as human bodies.

The divers said the debris was found 86 feet deep in the Atlantic, over an area about 50 feet wide. Most of the compartment was compressed into a single chunk, no more than 8 feet high, which contained the astronauts' remains.

Although federal investigators said last week they believe that the nose of the craft, containing the crew compartment, emerged intact from the fireball that destroyed Challenger nine miles above Earth, the crew compartment slammed into the water at about 180 mph -- a speed at which it would have crumpled as if slamming into concrete.

"It didn't really look like a vehicle, just a pile of rubble," said chief diver Thomas Stock.

He said the crew area -- a heavily reinforced, two-deck pressurized chamber with four astronauts on the upper deck and three beneath them -- was not intact.

"The remains were within the rubble," he said. "They weren't difficult to get."

Lt. Cmdr. Robert Honey, captain of the Preserver for about half of its two-month tour to collect Challenger debris, said the ship brought human remains to shore March 12 and 17.

"When we were coming in the first time," said Stock, "the whole ship was deadly silent. Everybody seemed to have the same feeling. We saw it on the news, but it didn't really hit you until we brought in the bodies."

Honey confirmed that there was conflict between his predecessor, Lt. Cmdr. James C. Devlin, and NASA over the level of ceremony the astronauts should be accorded as they were brought ashore. NASA objected to the Navy's desire for a formal honor guard.

A heated radio exchange with officials on shore ended with Devlin saying angrily: "This is Preserver. Aboard Preserver, it's my call." Both times the ship brought remains to shore, Honey said, crew members in dress blue uniforms were arrayed on deck before flag-draped coffins. The honor guard apparently irritated space agency officials, who have tried to keep recovery of crew remains out of the public eye.

"I don't know if you'd call it a disagreement," said Honey, who relieved Devlin after all the remains had been brought to shore. "We just did what we thought was most respectful."

"We felt the pain with the rest of the nation," said Pete Harbachuk, an electrician on the boat. "It felt good to be able to bring back the remains to the families."