Clipper could also support exploration of the Moon. The concept could even be aimed at going much further.

The availability of more than one transportation system offers a robustness that has great advantage over reliance on a single system. We would like an independent way of getting access to the International Space Station (ISS).

It's really an end-to-end space system, not just a vehicle.

It's like the station's arm, capable of walking from base point to base point.

It gave us the opportunity of completely cleaning that up and replacing it rather than doing a botch up and keeping our fingers crossed.

We're desperately anxious to get Columbus up. Having 10 tons of hardware sitting around in Bremen, or even in Florida, doesn't do a lot for you.