For the second time in four days, the maiden flight of a powerful new commercially developed rocket designed to boost space station cargo ships into orbit was called off Saturday, this time because high upper-level winds, officials said.
Launch from the Mid-Atlantic Regional Spaceport at NASA's Wallops Island, Va., flight facility was re-targeted for 5:00 p.m. EDT (GMT-4) Sunday. Forecasters predicted a 75 percent chance of acceptable weather.
Rocket-builder Orbital Sciences Corp. attempted to launch the 133-foot-tall Antares Wednesday, but the countdown was stopped at the T-minus 12-minute mark when engineers noticed a data cable that had prematurely pulled away from the booster's second stage.
Launch was re-targeted for Friday, but a dismal forecast prompted mission managers to slip another day to Saturday.
This time around, it appeared the weather would cooperate, but balloons found higher-than-allowable upper-level winds from a direction that could have blown debris from a launch failure into populated areas. Launch, originally targeted for 5 p.m., was delayed pending additional balloon data and, finally, called off for the day.
"The reduction in the high-altitude winds that we thought would happen did not," said Orbital Vice President Frank Culbertson, a former space shuttle commander. "It turned out we were red, as they say, for debris falling beyond the debris limit line, which is arranged ahead of time with the NASA range and the FAA."
Culbertson said the issue was "a matter of having winds that could potentially blow debris from a destructive event over populated areas. We had the rare case of wind coming from the southwest at high velocity."
With generally favorable weather expected Sunday, "we're going to target 5 p.m. tomorrow, same time, same place, same team," Culbertson said.
Alan Lindenmoyer, who manages NASA's commercial space effort, said the space agency agreed with the decision to stand down.
"We have learned to be very patient and wait until everything is ready," he said. "When it's right, we'll know it, and we'll give it a good go."
Orbital's Antares is the most powerful booster in company's inventory and the largest rocket ever built for launch from the MARS/Wallops complex. For its initial flight, the rocket is equipped with a dummy payload that simulates the weight of the company's Cygnus cargo ship.
The test flight and a so-called demonstration mission to the space station in mid June are part of a $288 million contract with NASA to help develop the new launch system. The first of at least eight operational station resupply flights conducted under a separate $1.9 billion contract with NASA, is targeted for mid September.
Space Exploration Technologies, or SpaceX, holds a separate $1.6 billion contract for at least 12 station resupply flights using the company's Falcon 9 rocket and Dragon cargo ship.