President Obama laid out his timeline and destinations for manned space exploration during a speech Thursday, a blueprint that includes a trip to Mars orbit and back in the 2030s. At the Kennedy Space Center in Florida, Obama pledged his commitment to the space agency and to manned exploration of the solar system, at a time when his controversial budget proposal for NASA awaits approval from Congress.

"As president, I believe that space exploration is not a luxury, it is not an afterthought," Obama said. "I am 100 percent committed to the mission of NASA and its future," he added later.

In a budget request released in February for fiscal year 2011, Obama asked for an additional $6 billion for NASA over five years, but he also introduced plans to cancel the Constellation Program, a family of rockets in the works to replace the space shuttle and return humans to the moon and to other targets in deep space. He proposed that commercial firms instead would launch astronauts to orbit after the shuttle is retired this year or in early 2011. The plan drew criticism from several members of Congress, particularly those representing districts where NASA is a major economic force, and left many experts concerned that exploration would be hamstrung without the kinds of definite goals on which Constellation had been built—notably returning humans to the moon by 2020.

Obama sought to neutralize both lines of criticism in his remarks Thursday, claiming that his plan would bring 2,500 extra jobs to Florida's Space Coast compared to the Constellation Program. He added that the administration was developing a $40-million plan for economic growth and job creation in the region, where layoffs from the shuttle program's phaseout are expected to hit hard. Obama also softened his proposal to eliminate Constellation entirely, saying that he had directed NASA Administrator Charles Bolden to begin work on an escape craft for the International Space Station that would be based on Constellation's Orion crew capsule.

Bolden had vowed in prior weeks that NASA's overarching long-term goal remained a manned mission to Mars, and Obama made that official by announcing his proposed timeline for human spaceflight in a series of what he called "specific and achievable milestones." Obama said that a heavy-lift rocket to enable astronauts' return to deep space would be fast-tracked. "We will finalize a rocket design no later than 2015 and then begin to build it," he said. On April 8 Bolden had announced that NASA's Marshall Space Flight Center in Huntsville, Ala., would receive $3.1 billion over five years under Obama's budget to develop new heavy-lift rockets.

By 2025, Obama said, the U.S. would develop a new spacecraft that can take astronauts beyond the moon and into deep space. "We'll start by sending astronauts to an asteroid for the first time in history," Obama said. By the 2030s, he continued, it will be possible to send humans on a two-way voyage to Mars, a mission that would be akin to the Apollo 8 mission of 1968 that set the stage for Apollo 11 the following year. "A landing on Mars will follow, and I expect to be around to see it," Obama said.