Gene Cernan went to space three times, including his final mission as commander of Apollo 17, when he became the last man to set foot on the moon.
That was in 1972. Now almost 40 years later, Cernan says going to theÎ¾ moon and beyond is still relevant.
"Space program is not a gift to anybody, it's not an entitlement, it's an investment. Probably one of the best investments this country has made not just in the future of the country itself, but in technology, in science, in education."
Cernan says after the moon landings, he believed NASA would have astronauts on Mars by the turn of the century. Instead, he says his glass is half empty.
"Because the President's budget, right now takes the United States of America out of the manned spacecraft business. We talk about developing technology — you gotta have a reason, you gotta have an incentive to develop technology. Without the dream, there's no technology, there's no reason to develop it."
Although President Obama actually increased NASA's budget, it does require the agency to shift away from space exploration.
"Quite frankly, I'm a little disappointed, a little concerned about where we may go as a nation into the future."
Cernan says NASA administrators are putting a positiveÎ¾spin on the loss of the Constellation program. NASA will retire the space shuttle at the end of this year. After that, the space agency has no plans to develop new vehicles for space exploration.