Astronauts working for the government will always need to be either pilots or mission specialists. Those who want to be pilots should have military experience - ideally, a test pilot background.

I'm in favor of changing the destination of humans. There are a lot of manned missions that can be done, but not in the direction of the moon.

Standing on the Moon looking back at Earth - this lovely place you just came from - you see all the colours, and you know what they represent. Having left the water planet, with all that water brings to Earth in terms of colour and abudance life, the absence of water and atmosphere on the desolate surface of the Moon gives rise to a stark contrast.

Exploring Mars is a far different venture from Apollo expeditions to the moon; it necessitates leaving our home planet on lengthy missions with a constrained return capability.

The biggest benefit of Apollo was the inspiration it gave to a growing generation to get into science and aerospace.

As someone who flew two space capsules and twice landed in the ocean, I can attest from personal experience how much logistics work is needed to get you home.

My family has always supported my activities, whether it was doing combat in Korea, flying progressively and challenging fighter-jet aircraft in Europe, or studying for a doctor's degree at MIT. They have been always very supportive and understanding of the challenges and risks involved in my career. A family needs to work as a team, supporting each other's individual aims and aspirations.