I support Mars and Lunar colonies now. But I feel that NASA run operations won’t work. NASA has become too blunt an instrument. We get way too little bang for our buck with NASA. They need to evolve into a much smaller granting and underwriting operation. But no self-perpetuating bureaucracy ever voluntarily shrinks. So it is most likely that it will lurch on into the future, doing fewer and fewer missions while consuming huge amounts of capital that would be better spent in private hands.
As an example of how the NASA of the future might function, suppose the current Mars “Curiosity” mission had been set up as an “X-Prize” type operation, with the proviso that the company or organization that completes the mission as described in the grant also has exclusive exploitation rights to any developments, media coverage, inventions, procedures and discoveries on Mars. If they find diamonds, they have first claim because the territory mapped out by the rover belongs to them. Possibly an generous land grant would be a part of the deal.
The advantages to this type of system are clear and have historical precedent. Charles Lindbergh flew NY to Paris to win a prize. He did it as economically and quickly as possible. If NASA had undertaken this challenge, they would spend five years planning a massive expedition and then after that, might actually begin development of an aircraft. The Parisians would still be waiting at Le Bourget Field for the plane to arrive.