Houston, Feb. 6: Nasa officials have expressed doubt that a piece of foam debris from the external fuel tank that struck Columbia during its lift-off could have led to the destruction of the ship.
On Monday, officials identified damage caused by the impact during the launching on January 16 as a prime suspect in the series of failures that led to the Columbia’s break-up over Texas on Saturday.
But on Wednesday, Ron D. Dittemore, the shuttle programme manager, said he and other Nasa officials did not believe that the lightweight insulating material could have caused sufficient damage to be a primary cause of the shuttle’s disintegration.
“Right now, it just does not make sense to us that a piece of debris would be the root cause for the loss of Columbia and its crew,” Dittemore said on Wednesday afternoon at a briefing at the Johnson Space Center here.
“We don’t believe it’s this chunk of foam. It’s got to be something else that we don’t know about.”
He said that investigators were still seeking the “missing link” to explain the disaster.
Dittemore also dismissed speculation that the piece of foam could have been saturated with water or encrusted in ice that made the chunk heavier and thus magnified the damage to the shuttle’s heat-dissipating tiles on the underside of the left wing.
Though the foam-covered tank sat on the Cape Canaveral launching pad for 39 days and was exposed to several heavy rainstorms before lift-off, Dittemore said the foam was designed to be impervious to moisture.
He also defended an engineering study, conducted during the shuttle mission and ratified by him and other senior managers, which concluded that damage from debris would not affect flight safety.
He said the shuttle’s crew had been involved in the discussions about the debris impact and did not raise any concerns about damage to the craft.
He said that engineers were continuing tests to try to determine whether a bigger or heavier piece of fuel tank debris could have caused enough damage to lead to the destruction of the shuttle.
Experts who have studied investigations like this one say it is too soon to rule out any potential cause. Seventeen years ago, after the shuttle Challenger exploded, engineers played down the possibility that faulty O-ring seals could have leaked to cause the accident, only to reverse themselves weeks later.
Still, Dittemore’s doubts about the foam theory seem to deepen the mystery of what caused the cataclysm that cost the shuttle’s seven astronauts their lives.