Head of NASA Ames Research Center, Dr. S. Pete Worden, has said that he expects any colonization of Mars, the Moon, or asteroids to be done by private companies.
Dr. Worden has been very valuable to NASA: "In the past three years, Worden has completely transformed Ames, reinvigorating the center’s workforce and taking a leadership role in important, cost-effective small satellite missions. "
According to The Register, Worden told them that "the agency was firmly enmeshing itself with the private sector. [...] governments can develop new technology and do some of the exciting early exploration but in the long run it's the private sector that finds ways to make profit, finds ways to expand humanity. That's really our tack."
He explained that explorations throughout history have tended to be paid with moneys from independently wealthy individuals, government funds, and corporations.
Wealthy entrepreneurs like PayPal and SpaceX co-founder, Elon Musk, have held conversations with Worden about funding settlement missions to the moon. Musk believes that it is very important that humans become multi-planetary while they can.
Beyond funding concerns, there are other limitations to having NASA execute these types of missions. Settlement missions to Mars would have to be one way, and that is only something that can be achieved in the private sector. There is no government funded mission that could keep someone on Mars forever if they changed their mind.
Google has a team of engineers working on technology that it can sell to space companies and orbit-happy entrepreneurs like Musk. I call them Google SpaceGoods.
Tiffany Montague, a former US Air Force high-altitude pilot, is the manager of Google’s space initiatives. Her official work title with Google is "Intergalactic Federation King Almighty and Commander of the Universe." How humbling.
Montague says that Google's SpaceGoods are "[seeing] an emerging market. Not everything we do is tied to immediate revenue; we take a long-range view of the world. That said, we hope in the very long run that they will make money too."
This commander has applied to become an Astronaut twice and hopes that everyone will be able to enter space if they want.
Her desire to become space bound is so strong that she even told The Register that if she can't get a trip to the moon in her lifetime she will try to increase her odds with cryogenics.
Imagine Montague in 2222 A.D. coming to from her cryogenic coma. When she is asked who she is and states that she was a pilot and Intergalactic Federation King Almighty and Commander of the Universe for Google, people might think she is a goddess from the future.