The formula of the kinetic energy is:

where m is a mass of the object, v is speed of the object at the moment of time. So we have:

The answer is
2000 Joules.
When in the melting process particles start to move more freely when in the freezing process particles tend to slow and vibrate in place
The mass of the astronaut is still 65 kilograms. Mass is constant or doesn't change no matter where you are.