NASA down to one commercial supplier to ISS

NASA is down to one commercial provider of cargo to the International Space Station until an investigation determines what caused an unmanned Orbital Sciences Corp. rocket to blow up Tuesday evening shortly after lifting off from a Virginia pad.

The Antares rocket's failure leaves SpaceX as the only U.S. company able to fly cargo to the orbiting laboratory for the near future, raising the stakes of SpaceX's next launch from Cape Canaveral, Fla., which is planned no earlier than Dec. 9.

A Cygnus spacecraft packed with more than 5,000 pounds of equipment and science experiments was destroyed Tuesday when the 14-story rocket suffered a problem with its first stage and fell back to the ground, generating a massive fireball on impact.

No one was injured. The severity of damage to the Wallops Island launch pad was not immediately known.

NASA said the station and its six-person crew would be fine despite the loss of supplies, including more than 1,300 pounds of food, 1,600 pounds of science investigations and some spare parts and spacewalking equipment.

"We're in good shape from a consumables supplies standpoint," said Bill Gerstenmaier, head of human spaceflight programs at NASA headquarters, during a press conference late Tuesday.

The station has enough food to last through March if no other resupply vehicle visits.

But in addition to SpaceX's upcoming launch, a Russian Progress freighter was scheduled to launch early Wednesday morning from Kazakhstan.

NASA and Orbital immediately began an investigation likely to keep the Antares grounded for months.

"Something went wrong and we will find out what that is," said Frank Culbertson, a former astronaut who leads Orbital's Advanced Programs Group. "It's a big disappointment to not be able to successfully deliver that cargo."

The Antares had launched successfully four times, including a maiden flight last year.

Tuesday's mission was Orbital's third of eight planned under a $1.9 billion NASA resupply contract. The rocket and spacecraft were worth more than $200 million.

Speculation immediately focused on the Antares rocket's two AJ26 main engines, which were built in the 1970s for a Soviet-era moon program and refurbished in the United States by Aerojet Rocketdyne.

The decades-old AJ26 engines have experienced problems during tests, with one catching fire in 2011 and another lost completely on a test stand earlier this year.

Culbertson said it was too soon to guess what went wrong. Investigators will collect debris from the two-stage, liquid- and solid-fueled rocket as well as study telemetry and video evidence secured after the accident.

The Antares was developed under a NASA program established to provide commercial cargo deliveries after the shuttle's 2011 retirement.

The program has been hailed as a success, helping Orbital and SpaceX develop new rockets and spacecraft for less than $800 million in taxpayer funds.

SpaceX recently completed its fourth successful resupply run under a $1.6 billion contract.

Antares is not one of the rockets that will fly NASA astronauts by 2017, so the mishap has no direct impact on future planned commercial launches of crews from Florida.

But the accident seems certain to heighten safety concerns about those launches, which are managed by a Kennedy Space Center office, and could make them more of a target for critics.

The mishap came a day before a quarterly meeting by an independent safety panel formed after the fatal Apollo 1 fire.

U.S. Sen. Bill Nelson, D-Fla., offered a vote of confidence to the commercial launch providers.

"Space flight is inherently risky," he said in a statement. "As we push the frontiers of space there will be setbacks. But our commercial space ventures will ultimately be successful."

SpaceX CEO Elon Musk also offered sympathetic remarks to Orbital.

"Hope they recover soon," he said on Twitter.

While the failure was a significant setback, NASA and Orbital stressed that there was no loss of life and the cargo could be replaced.

"This just reminds us how difficult this business is, how careful we have to be, how small things really matter in this launch business," said Gerstenmaier.

"We will fly again as soon as we can safely, with confidence," said Culbertson.