私人航天器准备好发射到国际空间站

A private company is attempting to send its newly designed cargo rocket to the orbiting International Space Station - a feat that has only been accomplished by governments.  The SpaceX launch, which has been delayed several times, is now set for May 19.

This animation shows what space station partner nations and SpaceX hope to see on launch day.   The Falcon 9 rocket, carrying its Dragon capsule, will launch from Cape Canaveral in Florida.  The cargo-carrying space capsule will separate from the rocket and begin its day-long journey toward the International Space Station.    

SpaceX officials caution that many things can go wrong with such complex new technologies.   The Dragon needs to meet up with an orbiting lab that is zooming around the Earth every 90 minutes, SpaceX CEO Elon Musk explained at a NASA news briefing in mid-April.

"So you've got to launch up there, you've got to rendezvous and be tracking the space station to within inches really, and this is something that is going 12 times faster than a bullet from an assault rifle. So it's hard," Musk admitted.

If Dragon's systems and sensors check out, the station crew will capture the capsule with the station's robotic arm.

ISS astronauts have plenty of supplies, so there won't be an issue if Dragon - essentially a robotic spaceship -  is not able to dock. 

"It's not as though there is somebody flying it with a joystick or that there is somebody on board who can make real-time corrections," noted Musk. "Dragon is making decisions all the time to optimize the probability of success, so there's a lot of intelligence on board the spacecraft."

NASA Administrator Charlie Bolden is optimistic.

"If all goes well, SpaceX will launch Dragon and they'll rendezvous with the station and be berthed in a matter of days,: he said. " And that will be the beginning of a totally new era, an era of private access to low-Earth orbit, the International Space Station and other destinations there."

NASA used its space shuttles to bring cargo to the ISS before it retired the shuttle fleet last year.  The U.S. space agency is now investing in private companies to handle low-Earth orbit transportation, and it has invested $381 million in SpaceX's commercial cargo capabilities.