(CNN) — Decades-old Russian engines are believed to have caused the Antares rocket’s failure to launch properly, Orbital Sciences Corp.’s CEO David Thompson said Wednesday.
“Current evidence strongly suggest that one of the two AJ26 main engines that powered Antares’ first stage failed about 15 seconds after ignition,” Thompson said in a conference call with investors.
Last week, a company spokesman said the unmanned rocket, which exploded in a fireball at NASA’s Wallops Flight Facility in Virginia,was deliberately destroyed after it became apparent there was a problem.
The turbo pump in one of the engines likely failed, Thompson said Wednesday. Orbital will likely stop using these engines, he said, since they have proven to be unreliable.
The Antares rocket and Cygnus cargo spacecrafthad been set to carry roughly 5,000 pounds of supplies and experiments to the International Space Station.
Despite what Thompson described as a “setback,” the company plans to stay on track with its $1.9 billion NASA contract delivering cargo to the space station, he said.
Orbital hopes to launch its Cygnus spacecraft using third-party rockets, he said.
There are three companies in the running: two from the United States and one from Europe.
Thompson would not reveal which companies, but said a decision is expected within a month.
SpaceX and United Space Alliance, the two likely U.S. companies — operate regular launches at Cape Canaveral Air Force Station in Florida. Orbital Sciences, SpaceX and the Russians’ Soyuz all regularly fly cargo and supplies to the six astronauts and cosmonauts stationed on the space station.
While using another company’s launch vehicle, Orbital will concentrate on replacing the 1970s-era Russian engines by 2016.
Thompson thanked NASA for its support.
“We look forward to working closely with them to quickly recover from last week’s setback,” he said.
