CAPE CANAVERAL, Fla., Oct 17 (Reuters) - Orbital ATK Inc plans to launch a revamped Antares rocket on a mission to supply the International Space Station on Monday, returning to flight for the first time since an older version of the booster exploded during liftoff two years ago.
The Antares, now outfitted with a pair of Russian-made engines, is scheduled to blast off at 7:40 p.m. EDT (2340 GMT) from a repaired launch pad on Wallops Island, Virginia.
Perched on top of the rocket is a Cygnus cargo ship loaded with 5,290 pounds (2,400 kg) of food, supplies, equipment and science experiments for the space station, a $100 billion laboratory in orbit about 250 miles (400 km) above Earth.
"We've missed these guys," Joel Montalbano, NASA's deputy station manager, told reporters during a prelaunch press conference on Saturday, referring to the Antares team.
The mission became more crucial for the U.S. space agency after a Sept. 1 accident destroyed a Falcon 9 rocket operated by Elon Musk's SpaceX and a $200 million Israeli communications satellite.
The accident, which occurred while the rocket was being fueled for a routine prelaunch test, has temporarily grounded SpaceX, the only company apart from Orbital currently contracted by NASA to fly cargo to the space station.
Private contractors for the cargo runs became necessary following the retirement of the space shuttles in 2011.
With SpaceX sidelined, NASA added extra food, clothing, laptop computers and spacesuit parts to the Cygnus cargo list, Montalbano said.
The last launch of an Antares rocket, on Oct. 28, 2014, ended in disaster a few seconds after liftoff. After the accident, Orbital sped up plans to replace the rocket's Soviet-era engines with the new Russian-made motors.
During the downtime, Orbital bought rides for two Cygnus cargo ships aboard Atlas rockets, built and flown by United Launch Alliance, a partnership of Lockheed Martin Corp and Boeing Co.
Orbital conducted a 30-second engine test firing of the Antares at the Virginia launch pad on May 31.
"We're always nervous, but we wouldn't have a rocket out there if we weren't confident we were ready to go," Orbital vice president Mike Pinkston told reporters on Saturday.
Orbital is counting on a smooth Antares launch to help attract other customers for the rocket besides NASA. The booster, designed to put up to about 17,000 pounds (8,000 kg) into orbit close to Earth, flew four times successfully before the 2014 failure.
Editing by Letitia Stein and Tom Brown