1.   At first, this form of space travel seemed possible.

2.   Large rockets are used for space travel and exploration.

3.   Many argue that the biological effects of lengthy space travel are the biggest imponderable.

4.   There is no doubt that the inhabitants once possessed space travel.

5.   This obviously raises great possibilities for space travel.

6.   This would be the ideal method of long-distance space travel mentioned earlier.

7.   What will space travel be like in the future?

8.   Who predicted space travel and submarines years before they became a reality!

9.   The Teefal saucepan that you have at home, er came doubtless from scientific research into space travel.