For more than 50 years, America’s inspiring strides in space exploration earned the respect of adversaries and allies alike. The Apollo missions launched explorers to the moon. The space shuttle flights united 15 nations to build the International Space Station. Today’s robotic explorers travel the solar system unlocking planetary secrets.

Decades of U.S. space successes have paid big dividends — remarkable technological advances that have boosted the American economy, strengthened national security, enriched our lives and created opportunities for all.

Now our next-generation space exploration goals are threatened. For the past 20 years, NASA’s budget has remained static or declined, slowing our exploration pace to a crawl. The 2013 NASA spending plan submitted to Congress totals $17.7 billion — less than half of 1 percent of the $3.8 trillion federal budget.

This means that less than half of a penny of each dollar the government spends goes toward American space programs. By comparison, we spend almost 10 times as much on the Department of Agriculture and 40 times as much on national defense in a federal budget that is increasingly dominated by commitments to Medicare, Social Security and other entitlements.

It’s time to dream big, recommit and reinvest by gradually doubling NASA’s budget to $35 billion, or 1 percent of the federal budget.

It’s a proposal that is gaining popularity, thanks in part to Neil deGrasse Tyson, astrophysicist and director of the Hayden Planetarium. During his testimony earlier this year to the Senate Commerce Committee, he described how doubling NASA’s budget would pay big dividends.

“Epic space adventures plant seeds of economic growth, because doing what’s never been done before is intellectually seductive and innovation follows, just as day follows night,” said Tyson, who often serves on White House advisory panels.

In 1966, with the moon landings still an uncertainty, the nation mired in an unpopular war and confronting civil unrest, our policymakers found NASA worthy of a 4.4 percent share of the federal budget. NASA spending fell below 1 percent in 1993 and has steadily declined since.

Should we stay on this present course, the United States will soon be outpaced by other countries. Russia, India and Brazil have embraced 20 percent increases, according to the Space Report 2012, an annual assessment of the global space economy from the Space Foundation. Both China and Russia are planning for an eventual human presence on the moon and a larger share of a growing global space economy, estimated by the foundation in 2011 at $289.8 billion.

We must reverse that trend. Our policymakers must renew the bipartisan tradition of supporting an ambitious space enterprise that will spur a bright future for the nation. They must set clear goals and stick by them. They must enlighten constituents on the many benefits that justify the appropriate investments we now seem too hesitant to make, even as they address the other pressing issues that have divided us for much too long.

Spaceflight challenges our nation’s engineers and scientists like no other peacetime pursuit. As these experts stretch to overcome the obstacles, they leave a rich legacy of technology with a track record of saving lives, conserving energy, enhancing national security and creating jobs. The future human exploration of the moon, asteroids and Mars will test NASA’s ability to recycle water and air and stretch the reach of terrestrial medicine, each a technology that promises to have far-reaching benefits on Earth.

NASA’s diminishing share of federal discretionary resources threatens to extinguish this bright future. Progress in space cannot be turned off and on like a water faucet.

To be clear, bigger space budgets are not a panacea. Success depends on a stable, skilled workforce and experienced leaders who know how to manage risks. It will take the best efforts of NASA, the commercial space industry, a skilled and smartly led industrial base, strategic partnerships within the research community and the educational system. Collectively, we will explore new worlds and solve even greater challenges here on Earth.

Leading on the frontier won’t be easy. President John F. Kennedy reminded us of this fact nearly 50 years ago when he rallied America in the race to the moon.

“The exploration of space will go ahead, whether we join in it or not, and it is one of the great adventures of all time, and no nation which expects to be the leader of other nations can expect to stay behind in this race for space,” Kennedy said in his famous Rice University speech in 1962. “We set sail on this new sea because there is new knowledge to be gained, and new rights to be won, and they must be won and used for the progress of all people.”

The soundness and wisdom of those remarks have not changed.

It’s time to make a bold move and double NASA’s budget. With the world’s largest economy, we can afford to make this wise, 1 percent investment. Our nation’s future depends on it.

Fred Gregory and Tom Jones are members of the board of advisers of the Coalition for Space Exploration.