For all the debate surrounding U.S. President Barack Obama’s recently released NASA budget request, the president got at least one thing unquestionably right. For the second year in a row, the Obama administration is asking Congress for at least $30 million to begin a multiyear effort to restart domestic production of plutonium-238, the essential ingredient in long-lasting spacecraft batteries crucial for sending landers and probes to sunlight-deprived corners of the solar system.

The United States stopped making the radioactive material in the 1980s and has been relying ever since on a now nearly depleted national inventory supplemented by periodic purchases from a recently uncooperative Russia.

Last year, the congressional appropriators who control the U.S. Department of Energy’s purse strings denied President Obama’s $30 million request for reviving a domestic plutonium-238 production capability, telling the administration it needed to come back with “an equitable and appropriate cost sharing strategy” before they would approve funding for a project expected to take seven years and cost at least $150 million to complete. The Energy Department is the U.S. government steward of all things nuclear, even though the users of plutonium-238 are NASA and the national security community.

The budget President Obama delivered to Congress Feb. 1 splits the $30 million tab for preliminary design and engineering work to restart plutonium-238 production between the Department of Energy and NASA.

For the U.S. taxpayer, $30 million is $30 million — it all comes out of the U.S. Treasury. But for House and Senate appropriators responsible for crafting spending bills that adhere to certain agreed-upon ceilings, the 50-50 split between NASA and the Department of Energy should make the president’s request easier to swallow since the two agencies are funded under separate bills.

With NASA now poised to invest in the production of plutonium-238, the agency has renewed incentive to finish and fly a new generation of radioisotope power systems that are four times more efficient than the plutonium-powered batteries flying today aboard the Voyager, Cassini and New Horizons spacecraft. It was encouraging in that regard to see that NASA’s proposed planetary science budget for 2011 includes money to develop a flight-qualified Advanced Stirling Radioisotope Generator that the agency has told scientists it is willing to furnish for a competitively selected Discovery-class mission on the books for a 2016 launch.

President Obama’s NASA budget also includes support for nuclear thermal propulsion and nuclear electric propulsion research under a $650 million Exploration Technology and Demonstration funding line projected to triple by 2013.

Nuclear propulsion research experienced a brief revival seven years ago when then-NASA Administrator Sean O’Keefe established Project Prometheus to design reactor-powered spacecraft capable of carrying unprecedented arrays of science instruments to the outer planets. Mr. O’Keefe’s successor, Mike Griffin, wasted little time pulling the plug on NASA’s nuclear ambitions — and a billion dollars worth of other technology projects — as he focused the agency’s limited resources on getting astronauts back to the Moon.

NASA has since been told to forget the Moon and instead develop technologies that one day will enable astronauts to reach more-distant yet unspecified destinations; critics say this bottom-up strategic ordering will not focus resources in a way that is necessary to make real headway in human exploration. But in the field of robotic planetary exploration — something NASA does better than anyone else — distant destinations have been identified, as have the technologies needed to reach them with probes equipped to do lengthy and detailed studies. Chief among these technologies are nuclear power and propulsion, a fact that fortunately has been recognized by the White House.