Astronauts on board the international space station got a chance earlier today to see the private unmanned Dragon spaceship that was launched on Tuesday by SpaceX, of Hawthorne, Calif.
NASA astronaut Don Pettit, who is living on the station, was talking to Houston's Mission Control when he suddenly reported that he had spotted Dragon. "I'm looking at Dragon right now," he said.
"We copy. Tally-ho on Dragon! That's great," replied Mission Control.
Images taken by the station's cameras showed the capsule looking like a small dot as it flew along a path that took it about 1.5 miles under the outpost. NASA put video of the flyby online.
The close flyby gave controllers a chance to check out critical systems on Dragon, to make sure all is working well as NASA decides whether to proceed with a rendezvous Friday morning that could end in docking.
If that happens, it would be a historic first for commercial spacecraft, as the space station has previously only received visiting spaceships flown by government agencies from the United States, Russia, Japan, and the European Union.
During the flyby, station astronauts successfully sent a command to Dragon, telling the capsule to turn on a strobe light. That was a key milestone, because the crew will need to be able to communicate with Dragon during tomorrow's maneuvers.
And controllers checked out the GPS systems that the spacecraft uses to determine its location relative to the station. NASA said via Twitter that the initial data was looking good.
If all continues to go well, NASA will give the go-ahead for Dragon to creep closer and closer to the station on Friday morning. It will halt 32 feet from the outpost and Pettit will use a robotic arm to grab the capsule and attach it to the station.
After that, astronauts will open the hatch and unload the capsule's cargo, which includes food and clothing. The crew will then load the vehicle with stuff to send home, and Dragon is scheduled to depart from the station on May 31, splashing down in the Pacific.
SpaceX was founded in 2002 by Elon Musk, who made his fortune building up the internet service PayPal, and the company has a $1.6 billion contract with NASA to deliver cargo to the space station now that the agency has retired its space shuttles.
So far, the company's first attempt to reach the station has been trouble-free. And the mission has gotten a lot of attention. In a Twitter update, Musk said: "The President just called to say congrats. Caller ID was blocked, so at first I thought it was a telemarketer :)"
(Nell Greenfieldboyce is an NPR science correspondent.)