If someone mentions space station, you probably are thinking of the one floating right above Earth, or perhaps a future one when (if?) we make it to Mars.

But the newest space station might actually circle a familiar celestial orb: the moon.

That’s according to a procurement request from NASA, which is asking private companies to bid on the development of a new space station that would loosely orbit the moon starting in 2022.

In theory, the Lunar Orbital Platform-Gateway could function as a jumping-off point for manned missions to the moon, including to its relatively unexplored far side. The station could also help prepare astronauts for Mars.

The Lunar Orbital Platform-Gateway “will give us a strategic presence in the lunar vicinity,” then-NASA acting Administrator Robert Lightfoot said in a press release in February (PDF).

It might seem fairly straightforward to build a station orbiting the moon, but there are hiccups. The station would be too far from Mars to handle lunar missions on its own. It would need support from another, smaller moon-orbiting station and landers that NASA hasn’t even proposed to build. Meanwhile, the red planet is rapidly fading from NASA’s planning, potentially orphaning the Gateway station as far as Mars goes.

For that reason, experts warned that the Gateway station might not be very useful for productive space exploration. “It’s a mixed bag,” Matt Siegler, a former NASA scientist now with the Arizona-based Planetary Science Institute, told The Daily Beast.

But Siegler said that the moon and Mars aren’t really the point in building another space station.

The point, actually, is much more grounded than one might believe: China.

That’s because the Asian space power could be slinking ahead of the United States in the race back to the lunar surface. “China seems on track to send astronauts to the moon by the late 2020s, if not sooner,” Siegler said.

In that context, Siegler added, America’s new moon station represents a kind of extraterrestrial P.R. stunt—a significant piece of space hardware that NASA could launch before China’s taikonauts step foot on the moon. “The Gateway is basically a way to make a statement that the U.S. has a deeper space presence than other countries,” Siegler said.

Despite this logistical uncertainty, NASA is forging ahead, soliciting proposals from the industry for the initial Gateway components, and has asked Congress for $500 million to begin paying for them in 2019. NASA expects the station to cost $2.7 billion in total.

It’s not a new idea. The space agency first proposed a moon station in 2013 as a lunching pad for missions to intercept and redirect asteroids on a collision course with Earth. The asteroid-defense project ended in 2017, but the idea for the station survived.

“ The Gateway is basically a way to make a statement that the U.S. has a deeper space presence than other countries. ” — Matt Siegler, former NASA scientist now at the Planetary Science Institute

NASA spokeswoman Cheryl Warner told The Daily Beast that the Lunar Orbital Platform-Gateway—in appearance, a sort of miniature version of the International Space Station that orbits Earth—could “be moved between orbits,” allowing it to “support lunar surface missions as well as exploration farther into the solar system, including Mars.”

For NASA, a moon mission is much more urgent. NASA and private companies hope to discover valuable gases and minerals that can be mined and shipped back to Earth, or processed on the moon for use by a Mars mission or some future lunar base.

And then there’s the “dark” side of the moon. Every past manned mission to the lunar surface has explored the moon’s more easily accessible near side. Owing to the difficulty in getting signals past the moon’s bulk, only a few probes have gathered data on its far side. (Sunlight actually does hit the far side, so it’s not really dark.)

Beijing launched the most recent far-side moon probe back in May. A new U.S. station, reliably circling around the entire moon, could make far-side missions more routine for Americans. “If we are going to explore the unexplored, the lunar far-side is our obvious target,” David Kring, a researcher with the Texas-based Lunar and Planetary Institute, wrote in a 2018 paper endorsing the Gateway station (PDF).

But the Gateway station alone can’t return American astronauts to the lunar surface—either the near or far side. That’s because the station would travel along what NASA calls a “rectilinear halo orbit” that would bring it no closer than 1,000 miles to the moon.

That’s too far from the moon for efficient exploration. To support human astronauts or a large number of drones, the moon station would probably need help from a smaller sub-station orbiting just 60 miles from the lunar surface, as well as from a new generation of moon landers that NASA hasn’t even begun to develop, Siegler pointed out.

“I personally would like to see many lunar landers and a new [low] lunar orbiter,” Siegler said. “So if the Gateway lets that be done, I would support it.” But he added that it might be better to simply boost drones and human explorers straight from the Earth to the moon. Stopping over on the gateway station is “not necessarily cheaper.”

As for Mars, William Gerstenmaier, a NASA associate administrator, said the agency’s experience with the Gateway “would ultimately translate” to a manned mission to the red planet.

In 2015 Apollo astronaut Buzz Aldrin developed a loose concept for Mars landings that involves training astronauts during layovers aboard orbital moon bases. A moon station could also function as a gas station for Mars-bound spaceships.

But NASA has largely walked away from concrete plans to land astronauts on Mars. The agency’s official website vaguely states that a manned Mars mission should happen “sometime in the future.”

But there’s no real schedule. And NASA is no longer developing many of the key technologies for a manned Mars mission. A manned mission is “on total hold,” Chris Impey, a University of Arizona astronomer, told The Daily Beast.

Until NASA gets serious about a Mars mission, the Gateway station’s ability to support that mission is meaningless. “A fuel depot beyond the moon would be useful for further exploration and Mars missions, but that’s not part of the plan,” Impey said.

Too far from the moon to efficiently support lunar exploration and pointless for Mars without firm plans for an actual mission to the red planet, the Gateway has exposed itself for what it really is—a symbol, according to Siegler.

With China sending its own drones and people to the moon in the next few years, NASA and the White House appear to be spooked. They’re looking for a near-term moon station to send a message, even if that station is impractical. “The U.S. is obviously trying to make a political statement that they are the leaders in space,” Siegler said.