And the scientific payoff could be enormous - we're both very excited.

Most basically, it is seen as a bold venture for America that will have a host of scientific, economic and cultural payoffs throughout the 21st century.

The considerable scientific payoffs cannot by themselves justify a manned mission; robots could do the job more efficiently.

There is a scientific payoff for Iran in taking part in the cruise.

Unmannned projects can yield the same scientific payoffs at a far lower price, they say.

Backers, while admitting there was no guarantee of success, said the scientific payoff was potentially gigantic.

By far the greatest scientific payoff in space comes from unmanned spacecraft.

It devotes to scientific research and has achieved many scientific payoffs.

Aside from any scientific payoff, he said, continued monitoring of Earth can attract attention to the planet's problems globally and be a useful educational tool.

But the scientific payoff, in our view, would be far greater than any likely research benefits from the space station.