They seek the secret of speed, true speed, the speed of light, godspeed. The man is nervous, but he does not speak. None of them speaks. The man fears the unknown, but he fears the known much more. He fears what may lay beyond the silver void, but he also fears transistors and rivets and O-rings.
Assumption is the name of the demon of mankind.
What we know, we assume we will always know. The man is secure in the knowledge that the designers of the craft were secure in their knowledge. He knows they did not check everything. The spacecraft is the pinnacle of technology, and technology is the great shining altar upon which the soul of the world rests. The craft and the little men have left the cradle in which they were reared.