WASHINGTON — Four solid-rocket booster segments riding near the front of the freight train that derailed May 2 in Alabama are headed back to Utah where their manufacturer, Alliant Techsystems (ATK), will either use them for ground tests or thoroughly refurbish them.
George Torres, a spokesman for Magna, Utah-based ATK Launch Systems Group, said May 9 that NASA and ATK determined over the weekend of May 5-6 that the four booster segments riding toward the back of the train are probably still fit for flight and so will continue on to Florida. Once the booster segments arrive at Kennedy Space Center, they will undergo extensive inspection before NASA approves their use for an upcoming space shuttle mission.
NASA and ATK officials said the freight train was traveling under 6 kilometers per hour when the raised roadbed it was crossing collapsed, causing the front of the train to go off the tracks. The two locomotives fell onto their sides, pulling a passenger car with them, injuring six people. Four booster-carrying flatbed cars toward the front of the train also derailed, with one falling over onto its side. The other four boosters were on cars toward the back of the train and remained upright and on the tracks during the accident, the cause of which is still under investigation.
June Malone, a spokeswoman for NASA Marshall Space Flight Center in Huntsville, Ala., said data recorders on board the train to monitor ride conditions found that only the four boosters near the front of the train were jostled hard enough in the accident to disqualify them for flight.
“We have accelerometers on those cars,” Malone said. “The four in the front have acceleration data outside of the guidelines. The four in the back were within the guideline.”
Torres said the four boosters cleared to travel on to Florida were back in transit May 9 and were expected to reach Kennedy Space Center May 14.
“Once we get them there we will do additional extensive analysis, including X-ray and anything we can do to be absolutely sure they are OK ,” Torres said.
Four booster segments comprise a single 45-kilometer tall booster, two of which are needed to help the space shuttle lift off. Approximately two minutes into flight, the boosters are jettisoned, recovered from the ocean and sent back to ATK to be flushed and filled with new solid propellant, a hard rubber-like material called aluminum perchlorate.
Torres said the eight boosters ATK loaded on to the train April 27 for what was supposed to be no longer than a two-week trip were designated for shuttle missions slated for October and December.
Malone and Torres both said the derailment would not delay upcoming shuttle flights. The shuttle’s next liftoff is slated for June 8.
“We have two full sets that are completed for missions next spring and next summer that we could move up and basically swap them out,” Torres said. “We don’t see an impact to flight rate since we have these already completed.”
Torres said the four boosters being sent back to ATK’s manufacturing facility in Promontory, Utah, could be used in ground tests pending the outcome of planned inspections.
ATK conducts horizontal ground tests of shuttle boosters twice a year, usually once in the spring and once in the fall. The next such static fire is scheduled for May 24, according to Torres.
If ATK decides against firing the boosters involved in the accident, Torres said they would be flushed and refilled just like a spent booster recovered after a shuttle launch.
“The cases themselves are reusable regardless,” Torres said.