The first commercial cargo run to the International Space Station is off until spring.
SpaceX planned to launch its unmanned supply ship from Cape Canaveral on Feb. 7. But the company said more testing was needed with the spacecraft, named Dragon. And on Friday, officials confirmed the launch would not occur until late March.
Space station commander Daniel Burbank said as much as he'd like to take part in the historic event, it's important that SpaceX fly when it's ready. Burbank will return to Earth in mid-March.
"If that's not to be during our mission, then that's OK," Burbank said in an interview Friday with The Associated Press. "We've got plenty of other things to occupy us ... but they'll fly when they're ready and they'll fly when they need to."
Just over a year ago, the California-based Space Exploration Technologies Corp. launched a test version of the capsule, becoming the first private business to send a spacecraft into orbit and return it safely. NASA is counting on companies like SpaceX to keep the station stocked, now that the shuttles are retired.
Until then, the Russian, European and Japanese space agencies _ all government entities _ are picking up the slack as best they can, sending up regular shipments to the orbiting outpost.
SpaceX spokeswoman Kirstin Grantham pointed out that this is a developmental program for her company, and everyone wants it to be a complete success.
"It may take a little more time, but when it happens, it's going to be amazing," she said.
This first Dragon capsule to visit the space station will carry several hundred pounds of astronaut provisions _ nothing crucial, in case of a failure.
Astronauts aboard the space station will use a huge robot arm to grab and berth the Dragon.
"This will be one step in the long road to human expansion off of the planet into low-Earth orbit and beyond," space station astronaut Donald Pettit said Friday. He is barely one month into a five-month mission.
The beauty of the Dragon is that it will be able to return scientific samples to Earth, Burbank noted. None of the other countries' supply ships can do that; they burn up on re-entry.
Americans Burbank and Pettit, three Russians and a Dutchman make up the six-man crew.
NASA closed out its 30-year shuttle program last July.
"There have been some impacts ... the shuttle did all the heavy lifting" for space station, Burbank said. There's excess equipment and trash on board, especially given the loss of a Russian supply ship in a launch accident last year. Those cargo carriers are filled with garbage before being jettisoned.
"I think we're getting by OK," Burbank said, "but we need to have as much up-mass and down-mass capability as we can to support space station operations at the level we need it."
SpaceX _ run by PayPal co-founder Elon Musk _ is one of several companies vying for space station visiting privileges. Its long-term goal is to modify its Falcon rocket and Dragon capsule to ferry astronauts to the station.
In the meantime, Americans are buying seats on Russian Soyuz spacecraft.