News of the shuttle Columbia disaster hit the astronauts aboard the international space station especially hard. The crew, who lost their friends on Saturday, were scheduled to return home next month on the shuttle Atlantis. But now NASA has grounded all flights. Our Chris Simkins has more on the astronauts still in space and the future of research missions at the space station.

Imagine what it must be like to find out about the Columbia disaster up here. U.S. astronauts Kenneth Bowersox, Donald Pettit and Russian Cosmonaut Nikolai Budarin have been orbiting in the International Space Station since December. As many people have said they must be the loneliest men in the universe.

?They're grieving up there, also. And they feel a little isolated.?

NASA says the Space station astronauts are safe. On Tuesday an unmanned Russian transport spacecraft docked with the space station.

It brought food and fuel to the three-man crew. Officials say they have plenty of oxygen, food and supplies to last them until June.

And at all times a Russian Soyuz spacecraft is docked to the station so they can come home in case of emergencies. But they were supposed to get their ride back to earth next month on the shuttle Atlantis. Nobody can imagine that happening now.

?They committed themselves to stay up there for however long we needed in order to get the job done. ?

But today the pros and cons of building the station are in sharp focus. Professor Robert Park with the University of Maryland.

?What are we doing up there.?

Dr. Park is one of many who say the station is not the best way to spend money in space. He says it is draining resources that could go to robot ships, which do a lot more science for a lot less money.

?I sincerely hope that we will cut back on the amount of resources we devote to humans in space, and get on with the exploration of the solar system.?

Other people agree. They say that too much effort has already been spent on the space station. They add that it?s something important to world politics and for Americans and Russians to work together on in peace.

In a way some believe the space station has become NASA?s insurance policy. Space analyst John Pike says it?s harder to cancel the astronaut program when they are there.

?With permanent human presence on the station and with Russians to get the crew back and forth we can keep flying in space even though the shuttle is not.?

Millions of Americans clearly want astronauts as heroes just as they admired the crew of Columbia.