The explosion of a rocket carrying an unmanned spacecraft bound for the International Space Station last month was likely caused by a failure in the decades-old, Soviet-made engines, according to a preliminary probe by the rocket's maker.
As a result, Orbital Sciences Corp. announced Wednesday it would likely retire the Aerojet Rocketdyne AJ26 engines for future resupply missions to the ISS. No one was injured when the Anteres launch vehicleat NASA's Wallops Island Flight Facility in Virginia on October 28.
"Preliminary evidence and analysis conducted to date points to a probable turbopump-related failure in one of the two Aerojet Rocketdyne AJ26 stage one main engines," Orbital said in a statement. "As a result, the use of these engines for the Antares vehicle likely will be discontinued."
Originally part of the Soviet Union's unsuccessful plan to put cosmonauts on the moon in the 1970s, the engines were later acquired and refurbished by Aerojet Rocketdyne, which supplied the engines to Orbital.
Destroyed in the explosion was an Orbital-made Cygnus CRS-3 spacecraft ferrying about 5,000 pounds for resupplying the International Space Station - its largest payload to date -- as part of Orbital's $1.9 billion contract with NASA. The spacecraft was supposed to dock with the ISS on November 2, when the six-person crew of Expedition 41 was to unload the supplies.
For future missions, the company said it plans to accelerate introduction of an Anteres propulsion upgrade originally planned for 2017, allowing all remaining cargo to be delivered to the ISS by the end of 2016. The accelerated upgrade will not result in a cost increase to NASA, the Dulles, Va.-based company said in a statement.
"Orbital is taking decisive action to fulfill our commitments to NASA in support of safe and productive operations of the space station. While last week's Antares failure was very disappointing to all of us, the company is already implementing a contingency plan to overcome this setback," Orbital CEO David Thompson said in a statement.
October's launch was to be the third of eight planned Orbital cargo missions under its NASA contract. The five remaining resupply missions will be consolidated into four launches, Thompson said. The explosion is estimated to have destroyed at least $200 million in equipment and supplies.