NASA Administrator Charles Bolden on Thursday outlined field center assignments supportive of President Obama’s plans to replace the under funded Constellation program with new initiatives in commercial space transportation and “transformative” technologies that could pave the way for the future human exploration of Mars.

The White House strategy, which includes $6 billion in new funding for NASA over the next five years, has struggled to find Congressional backing.

Thursday’s announcements and the outcome of an April 15 space policy conference that President Obama plans to host at the Kennedy Space Center in Florida may offer lawmakers a new basis upon which to judge a strategy that will leave the United States without a way of launching astronauts once the shuttle is retired later this year.

It could be several years, at least, before the commercial space taxis the new initiative supports take flight. The White House plan is absent a spacecraft for deep space exploration and lacks a specific destination and timeline. However, the strategy offers the best opportunity to rebound from Constellation’s chronic under funding with a sustainable road map, according to Bolden.

“If we execute the budget as proposed, and we prove that we are on a sustainable path that is the best protection you have against a subsequent administration being forced to change course,” he told a news briefing.

“The goal of this program is to not be in this position in another four years,” NASA Deputy Administrator Lori Garver told reporters. “These technologies we are investing in allow you to leave low Earth orbit and go to the interesting places. As we have robotic precursor missions with our science portfolio we will be able to determine the best place to go. The future leaders of this nation should have the data to do it and the capability to do it in a sustained way that is more affordable.”

While Mars is often mentioned as the ultimate destination, the new approach is also intended to pave the way for missions to asteroids as well as the moons of Mars and the Earth’s moon.

Constellation emerged in the aftermath of NASA’s 2003 Columbia tragedy with a goal of returning humans to the moon by 2020. A re-assessment of the Bush Administration program by the Augustine Committee last year concluded the effort had been so under funded it was more than a decade from achieving the goal.

The space agency is comprised of 10 field centers, each with specific responsibilities for carrying out the Obama plan.

The Johnson Space Center in Houston, the Marshall Space Flight Center in Huntsville, Ala., the Kennedy Space Flight Center in Cape Canaveral, Fla., and the Glenn Research Center in Cleveland, Ohio would shoulder much of the development work associated with future human exploration. But the others would have significant roles as well.

The NASA administrator would have a strong hand in assigning the program offices to the centers he believes have the workforce best suited to carry out the development. In many cases, multiple centers will bear the responsibility for managing the largest of the projects.

For instance, the new Flagship Technologies Development Program Office, funded at $6 billion over five years, would reside at Johnson. The deputy program manager would reside at Kennedy.

Engineers will work on techniques for storing rocket propellants in space for long periods and on methods of refueling spacecraft from the fuel depots. Others would be assigned to develop structures that can be packed tight for launching and inflated in space to house astronauts. And others would investigate the means to shield astronauts on deep space missions from harmful levels of cosmic radiation.

Kennedy would manage NASA’s new Commercial Crew Development Office, with a $5.8 billion budget over five years to foster the growth of a commercial launch industry that can safely transport astronauts to and from the International Space Station. The program’s deputy director would reside at Johnson.