Jim Campbell/Aero-News Network (top);

Missouri Historical Society Photographs and Prints Collection (above)

PIONEERS Charles Lindbergh, with his “Spirit of St. Louis,”

and the developers of SpaceShipOne, top, earned prize money for their aeronautical feats.

When a documentary called “Who Killed the Electric Car?” came out in 2006, laying blame on the usual suspects — oil companies, automakers and the Bush administration — it was hailed by some viewers as a brave exposé and dismissed by others as a conspiracy theory. But the film’s broader thesis was hard to dispute. You don’t have to be paranoid to believe that the inertia of the status quo acts as a drag on innovation.

Declaring last week that he wanted to break the country’s oil jam by encouraging “heroic efforts in engineering,” John McCain called for the government to offer a prize — $300 million (a dollar an American) to the inventor of a battery so compact, powerful and inexpensive that it would supplement or even supplant the need for fossil fuels.

Barack Obama quickly derided the proposal — involving a sum equivalent to nearly 200 Nobel Prizes — as a gimmick and a distraction. But prizes are hard to resist. Mr. Obama’s own energy plan, posted on his Web site, suggests awarding them (in addition to tax incentives and government contracts) for ethanol research. But ultimately, he insisted, achieving energy independence will require a Kennedyesque effort like the one that put a man on the moon.

On one level the rhetoric was a replay of the old standoff between Big Government and the virtues of entrepreneurship. But it also raised deeper questions, like how best can the government finance and direct basic research without stifling something as mercurial as the spirit of invention.

Considering the bureaucratic bog the space program has waded into — the exhilaration of Neil Armstrong’s giant leap for mankind giving way to plumbing problems on the International Space Station — Mr. Obama might not have picked the best example. The latest pictures from Mars are stunning, but the most exciting thing to happen recently in manned space flight came in 2004 when Burt Rutan won the $10 million Ansari X Prize for the first privately backed suborbital excursion.

Winning the contest, which was named for its benefactors, the Ansari family, and administered by the nonprofit X Prize Foundation, cost more than the award was worth. (Mr. Rutan was backed by a Microsoft billionaire, Paul Allen.) But greater spoils may await, with Virgin Galactic licensing the technology for a space tourism industry.

This kind of leveraging is one of the selling points of sweepstakes science. The X Prize Foundation took as its model the 1919 Orteig Prize — $25,000 for the first nonstop flight between New York and Paris offered by a hotelier who figured it would be good for business. The purse was claimed eight years later by Charles Lindbergh, and the publicity jump-started American aviation.

Lindbergh’s grandson is a member of the foundation’s board, which is offering other prizes including the Google Lunar X Prize for the winner of an unmanned race to the moon; the Robert A. and Virginia Heinlein Prize, endowed by the family of the science fiction writer, “for practical accomplishments in the field of commercial space activities”; and the Archon X Prize for Genomics for the developer of a faster, cheaper way to sequence DNA.

None of these goals is beyond the reach of the government research establishment — which includes, along with NASA, the Department of Energy, the National Institutes of Health, the National Science Foundation and the Defense Advanced Research Projects Agency. But with formal proposals, peer review and Congressional oversight, it’s hard for administrators to jump quickly on a new idea — and there is always the danger of getting stuck in a rut. The system was designed to pick out the best people with the best ideas and to avoid political meddling. But you can never know until the end whether you have been backing the wrong team.

Hence the allure of prizes. They come unburdened by preconceptions and require little overhead, and development costs are often picked up by people like Mr. Allen. Best of all, the prize has to be paid only if there is a winner.

That in itself can raise questions about the seriousness of the commitment. Basic research consists of the gradual, meandering, sometimes tedious accretion of small details. That requires money up front. Practical applications, if there are any, may only be clear in retrospect.

Still, where there is a well-defined goal, prizes might lure talented mavericks who would otherwise get caught in the filters. An oft-cited case is the cash prize offered by Britain in 1714 for determining a ship’s longitude at sea. Had there been an 18th-century version of the National Science Foundation, grants would probably have gone to astronomers looking to the sky for a solution. (Latitude was measured that way, so why not longitude?) The winner, after half a century, was a clockmaker, John Harrison, who took an entirely different approach: devising an extremely accurate chronometer.

Determined to recapture its adventurous image, NASA has created its own prizes — through its Centennial Challenges program (established in 2003 to mark the 100th anniversary of the Wright brothers’ flight at Kitty Hawk). And the defense research agency’s Grand Challenge has pitted robotic cars against each other in a race to develop a vehicle that can navigate without a human driver or remote control.

There may be more to come. A recent report by the National Academy of Sciences suggested that the N.S.F. dip into the waters by experimenting with small prizes. But a discussion paper published in 2006 by the Brookings Institution called for a much bigger commitment, with government prizes ranging from $15 million for an Earth-Moon solar sailcraft race to as much as $100 million a year for improvements in African agriculture. Mr.

McCain’s own proposal for spurring development of alternative energy sources was foreshadowed by a bill introduced last year in Congress that would establish a prize for breakthroughs in the development of hydrogen power.

If the trend takes off there may be so many contests that they lose their appeal. But science will be in no danger. No prize will ever match the thrill of discovery — Marie Curie isolating a shimmering gram of radium from tons of uranium ore. And for the less inspired, there will always be the rewards of the marketplace.