WASHINGTON - NASA has started beaming live video from just outside the International Space Station, but there's a catch: The online feeds are available only when the station's crew is asleep or off duty.

That's because NASA has only four communications links for sending data to Earth and wants to have all of them free for day-to-day operations while the crew is awake and working, agency spokesman Kelly Humphries said.

NASA also opted not to show video from inside the cramped space station to give astronauts privacy. "It would be like Big Brother looking over your shoulder 24/7," he said.

When the crew is asleep and the Web streaming is going on, remote cameras will show Earth or other parts of the sky as seen from the space station, or parts of the station's exterior as it orbits 362 kilometres above Earth.

The rest of the time, while the crew is awake, viewers will get an illustration showing the station's current location or live NASA television coverage of breaking space events.

The live Internet feed will include audio from mission control to the station.

NASA already produces about an hour a day of live television coverage from the space station with commentary from Johnson Space Center in Houston. That program will now be available on NASA's Web site as well.