* Launch of Orbital Sciences' Antares booster reset for Sunday
* Second weather delay follows technical glitch on Wednesday
By Irene Klotz
CAPE CANAVERAL, Fla., April 20 (Reuters) - The test-launch of a new U.S. rocket to fly cargo to the International Space Station was canceled on Saturday due to a second day of poor weather at the Wallops Island, Virginia, launch site, officials said.
Liftoff of the Orbital Sciences Corp's Antares rocket was rescheduled for 5 p.m EDT (2100 GMT) on Sunday.
"Excessive wind levels have caused mission managers to delay the launch attempt (Saturday) of Orbital Sciences' Antares rocket at the Wallops Flight Facility, Va.," NASA wrote on its website.
"We will try again tomorrow," Orbital Sciences wrote on Twitter.
The Virginia-based company is one of two firms hired by NASA to keep the station stocked with food, supplies and science gear for the six live-aboard crewmembers following the retirement of the space shuttles in 2011.
Privately owned Space Exploration Technologies, or SpaceX, completed two test flights of its Falcon 9 rocket and Dragon cargo capsules and last year began delivery services under a 12-flight, $1.6-billion contract.
Orbital Sciences plans to follow up its Antares demonstration flight with a practice run to the station later this year. The company holds a $1.9-billion contract for eight station cargo runs. The Cygnus capsule is larger than Dragon and can carry more cargo.
Orbital Sciences initially planned to launch its 13-story- tall Antares rocket on Wednesday, but 12 minutes before liftoff engineers discovered that a data cable on the booster's upper-stage motor had disconnected.
A second launch attempt slated for Friday was called off because of poor weather.
Antares carries a dummy Cygnus cargo capsule that is expected to be put into orbit about 160 miles (258 km) above Earth. The space station, a $100 billion project of 15 nations, flies at an altitude of about 250 miles (400 km). Reaching the station will be the goal of Orbital Sciences' second and final test flight later this year.
In addition to the cargo resupply contracts, NASA contributed about $684 million to Orbital Sciences and SpaceX to develop and test their spacecraft.
The U.S. space agency, which is working on a heavy-lift rocket and capsule to fly astronauts beyond the station's orbit, also is backing SpaceX, Boeing, and privately owned Sierra Nevada Corp to develop commercial spaceships to taxi crews to the station, a service currently provided solely by Russia at a cost of more than $60 million per person.