1.   The spacecraft, with its nuclear rockets, would be launched on top of a conventional chemical rocket.

2.   As it was, conventional rockets fired from Lebanon injured four people in northern Galilee.

3.   As with conventional rockets, Lightcraft launches would have to be canceled during storms.

4.   Because it would not carry the heavy oxidizer at takeoff, the craft could be much lighter than a conventional rocket.

5.   But if conventional rockets are the hares of the Space Age, ion engines are the tortoises.

6.   Conventional rockets use oxygen stored on board.

7.   Conventional rockets are not totally reusable because they discard parts with each flight.

8.   NASA officials said the systems they envisioned would be launched by conventional rockets and not activated until safely in space.

9.   That means the telescope could fit in a conventional rocket, and then unfurl in space like a flower opening on a spring day.

10.   Although a solar sail is at first slower than a conventional rocket, it continues to accelerate over time and achieves a greater velocity.