This is a pointless exercise that is doomed to failure. Sure, we may be able to extend a person's life to 200 or 300 years. But will we be able to cure all future diseases (for the next million years), eliminate accidents, natural disasters, and sudden body failure? What about when the sun burns out in a few billion years? Will we be able to successfully colonize another planet while keeping the same safety precautions for human life?
Death is as much a part of life as birth. It will not be eliminated unless you eliminate life. To think otherwise is a denial of reality.