Kieron Moore is a scientist who is to test fly an orbiting spaceship. Unbeknownst to him the Government has also planned to take an experimental bomb along as well.
After the launch they discover a female reporter has stowed away in order to get a once in a lifetime story. They also discover that the bomb has attached itself to the tail of the ship and they only have a very few hours to try and disarm it before it explodes.
There is not tons of action as modern audiences are accustomed to, but this is a fine film that does make you think a time or two. The cast also includes Lois Maxwell as Kim Hamilton, the reporter who stows away, Donald Wolfit and Bryan Forbes. Recommended for those so inclined.