During the height of the Space Age, the United States and the Soviet Union bushwhacked a frantic path to the lunar surface, landing nearly 20 spacecraft softly on the moon between 1966 and 1976, including the six carrying NASA’s Apollo astronauts.

But after the last of these missions, a robotic Soviet probe that brought back six ounces of lunar soil, Earth’s closest neighbor was virtually abandoned.

While the occasional orbiter has launched to survey the moon since then, in more than 42 years only one spacecraft touched down softly on the lunar surface: China’s Chang’e 3 in 2013.

But now, the moon is again the center of a reinvigorated space race.

On Jan. 3, China landed a spacecraft on the far side of the moon, a historic first. This month, an Israeli spacecraft destined for the moon is scheduled to launch from Cape Canaveral, Fla. If successful, it would make Israel the fourth country to land a spacecraft on the lunar surface.

Later this year — the 50th anniversary of the first Apollo moon landing — two more moon missions are planned, one by India and another by China. On Thursday, NASA Administrator Jim Bridenstine announced the space agency intends to partner with the private sector to land an American spacecraft on the moon as early as this year.

“It’s important we get back to the moon as fast as possible,” he told reporters. “We’re going to take shots on goal.”

The Trump administration has said a return to the moon is a top priority. And NASA this month announced a plan to develop spacecraft capable of bringing humans to the lunar surface by 2028. That’s a key step, NASA says, in building a permanent presence on and near the moon.

Like the Cold War-era Space Race between the United States and the Soviet Union, the new lunar activity is fueled by national pride and a quest for scientific discovery in a high-stakes contest among countries, especially with China.

Yet, unlike the Apollo era, this Space Age is being driven by a third factor: Greed. A growing number of corporations are benefiting from new technologies and wealthy backers chasing an unproven dream that a lucrative business can be built on the moon and deep space by extracting the metals and resources on the surface on the moon.

Though the prospect of a self-sustaining lunar-mining economy may be little more than a chimera, the moon is drawing investors and explorers the way the promise of the American West once did. As a result, several lunar-prospecting companies have emerged with plans to fly spacecraft to the moon in the coming years.

They are attracted by “the gleam of the gold prospector going out to San Francisco in [1849],” said Ellen Stofan, the director of the National Air and Space Museum.

“Is there a profit motive yet?” Stofan said. “I would argue there’s probably not one. But I would argue that there is going to be someday. But is that someday in 20 years? Is it in 50 years?”

Space, especially deep space, is still very much the province of governments, not corporations. If the fear of being surpassed by other nations and the quest for knowledge are what have driven space exploration, it is still not clear that greed alone can sustain a commercial venture.

But that’s not stopping the more adventurous from trying.

There is gold on the moon and nearby asteroids. And silver, titanium and an isotope known as Helium-3 that could be used in nuclear fusion.

According to Congress, they are there for the taking. In 2015, it passed the Space Act, which, among other things, allows U.S. companies the right to the resources they mine in space.

Commerce Secretary Wilbur Ross, who has been working to reduce regulations on the space industry, is one of the chief proponents of the theory that space, and in particular the moon, could be an economic engine, fueled by mining and other activities.

“Space is already a $340 billion business. We think it will be into the trillions within not a huge number of years,” he said last year. “Space is the next truly huge frontier and a huge, huge opportunity for the United States.”

And NASA isn’t missing out on the moon rush.

The first act of the reconstituted National Space Council led by Vice President Mike Pence was to declare a return to the moon in partnership with the private sector. NASA recently took a first step announcing nine companies that had been chosen to compete to fly science experiments to the lunar surface, with the goal of landing as soon as this year. At stake in what’s known as the Commercial Lunar Payloads program is $2.6 billion over 10 years.

In addition to those small landers, the space agency is looking for spacecraft capable of taking people to the surface as part of its plan to build what it calls the Gateway, a spaceship that would stay in orbit around the moon.

With the NASA-funded moon programs, the private sector finally sees a revenue source that will help it close a business case.

“It’s like trying to roll a big boulder up a hill, and I think we’re reaching that tipping point where it starts rolling downhill,” said John Thornton, the CEO of Astrobotic, a Pittsburgh space-robotics firm. “And the biggest signal of that is NASA getting involved.”