Wreckage of the space shuttle Challenger reveals that the nose section containing the crew compartment split off under tortuous stress and hit the ocean relatively intact, a federal accident investigator said Wednesday.
Terry J. Armentrout of the National Transportation Safety Board said that only the right wing and right side of the tail of the orbiter showed signs of the fiery explosion on Jan. 28.
“The nose section is broken off in a clean fracture line,” he said. “It does not have any appearance of heat damage. It doesn’t show any extreme blast effects, because of the lack of any chemical deposits” from the explosion gases.
Debate on Shuttle Cabin
Armentrout’s disclosure may renew debate on whether NASA should try to design a shuttle crew compartment that could survive an in-flight accident.
Several astronauts, led by chief astronaut John W. Young, have urged that NASA consider some form of escape system. However, NASA engineers have contended that there is little likelihood of coming up with a cabin design or escape system that could ensure astronauts’ survival in the event of a Challenger-like accident.
All seven members of the Challenger crew, which included New Hampshire schoolteacher Sharon Christa McAuliffe, were killed in the accident. The explosion occurred 73 seconds into the flight at an altitude of roughly nine miles.
It is unclear at what point the astronauts died, but most experts do not believe that they survived the plunge into the ocean. The shock of the explosion or the instant decompression of the cabin could have killed them instantly.
Armentrout, who is on loan to NASA from his post as director of the transportation safety board’s Bureau of Accident Investigation, made his comments to reporters on a tour of two cavernous hangars housing the wreckage of the orbiter and its external fuel tank.
It was the first official look that reporters have been given of the debris from the shuttle accident 10 weeks ago. The remains of the orbiter are laid out on wooden trestles and pallets in a mock-up of its approximate shape.
Only about 20% of the wreckage of the orbiter has been recovered, including most of the right wing, parts of the fuselage and a large patch of the white-tiled outer skin of the nose section. Many of the twisted, jagged shapes of metal were encrusted with salt and barnacles. The hangar smelled of the ocean.
Tail Section on Truck
Three-quarters of orbiter’s vertical stabilizer, or tail, had arrived at the loading dock outside the hangar only Wednesday morning and still sat on a flatbed truck.
As he stood by the salvaged outer skin of the nose section, Armentrout noted that videotapes and films of the shuttle accident show an explosion that sent debris showering over hundreds of square miles of the Atlantic Ocean.
“But an explosion of the entire shuttle is not something that we are seeing,” he said. “The term explosion has been used for a long time, but we’re seeing an in-flight breakup due to overloads.”
In some videotapes, the forward part of the shuttle emerged from the fireball but then appeared to be battered by an explosion of monomethylhydrazine, which fuels the flight control system in the shuttle’s nose.
But investigators were surprised to find undamaged fuel tanks from that forward rocket system.
“We don’t have evidence that the (flight control system) exploded in flight,” he said. “We see more evidence of aerodynamic breakup.”
At a press briefing before the visit to the shuttle debris, Armentrout described the investigation of the shuttle accident as a “complex structural task.” Investigators have to deal not only with damage from the “breakup scenario” at the instant of the accident but also damage from midair collisions between broken pieces, from the impact of hitting water, from being on the ocean floor and from salvage equipment.
NASA spokesman Hugh Harris said that no decision has been made as to what to do with the Challenger wreckage after the investigation is completed. He noted that the remains of the Apollo that was destroyed in a launching pad accident in 1967 are stored in a warehouse.
Harris said that on April 18 NASA will present the results of its formal investigation to the presidential commission investigating the disaster. But Lt. Max Allen, a Navy spokesman, said that salvage efforts will continue.
Faulty Joint Blamed
NASA hopes to recover additional key parts of the right solid rocket booster. J.R. Thompson, vice chairman of the NASA investigation task force, said Tuesday that a faulty joint between the bottom two segments of that booster definitely caused the accident.
Allen said that only half of the 66 pieces of debris found by sonar and definitely identified as shuttle wreckage has been recovered. Moreover, he said, there are more than 500 additional sonar contacts that have not been identified.
“Until they send down divers or manned submersibles, they don’t know what they’ve got,” he said. “Some of them may turn out to be kitchen sinks, sunken boats or just big rocks.”