Washington ? Charles Bolden’s task as new chief will be more difficult and complex than merely restoring the National Aeronautics and Space Administration to its glory days of the 1960s, when the United States raced and beat the Soviet Union to the moon.

In announcing Bolden as his pick to lead NASA, Obama on Saturday gave little hint of the challenges that the Columbia, S.C., native will face if, as expected, he wins Senate confirmation.

Bolden, Obama said, “will help put NASA on course to boldly push the boundaries of space, aeronautics and exploration in the 21st century, and ensure the long-term vibrancy of America’s space program.”

Obama tapped Lori Garver, an aeronautics consultant who led his presidential transition’s review of NASA, to be deputy administrator of an agency that’s still haunted by the space shuttle tragedies of the last two decades.

Bolden, a 62-year-old retired Marine Corps general, would be the first African-American and only the second astronaut to head NASA. He did not respond Saturday to requests for comment and said recently he is “under an embargo.”

Bolden’s toughest assignment is bridging the divide within NASA and among its powerful contractors between its glamorous traditional mission of manned space exploration and an expanding research focus made more urgent by climate change and other environmental issues.

“These are two separate challenges,” Franco Enouldi, the director of earth sciences at the Goddard Space Flight Center in Greenbelt, Md., said in an interview. “People will differ on which one is more important. Are the funds there to accomplish (both) missions? That is a serious question whose answer is not clear.”

Obama has formed a commission to study the future of NASA, and he summoned Bolden to the White House on Tuesday to gain assurances that its prospective leader would implement its recommendations.

President George W. Bush made a splash just after his re-election in January 2004 when he called for returning an astronaut to the Moon by 2020 and landing an American on Mars by 2030.

Many space experts consider those goals costly and unrealistic, especially at a time of financial crisis when huge amounts of federal money are being devoted to restoring the economy, fighting wars in Iraq and Afghanistan and combating terrorism.

Bolden’s background as an astronaut who logged 680 hours of space flight time prompts concern among some scientists that he’ll favor the expensive endeavor of flying Americans through space.

Bolden gets a warmer reception from the Coalition for Space Exploration, a group of space industry businesses.

“Bolden is a strong and experienced leader who will balance the priorities of the agency,” said Dean Acosta, a Boeing executive and spokesman for the coalition.

“America’s space program is at a critical crossroad,” Acosta said. “NASA needs a clearly defined plan and unwavering support from our president and Congress to achieve our nation’s space exploration objectives.”