“We care about speed,” Thomas Zurbuchen, the associate administrator of NASA’s science division, said recently. “We want to start taking shots on goal. We do not expect that every one of those launches, every one of those landings, will be successful.”

Why the urgency? One interpretation: Trump is more than halfway into his first term, and his administration is ready to put months of planning into motion. Another: Trump is more than halfway into his first term, and the administration still has little to show for itself, especially as the Apollo anniversary approaches. Officials say they could sign the first contracts as soon as July, just in time for the occasion.

The administration’s vision calls for the construction of a lunar outpost—the equivalent of a little International Space Station, orbiting the moon. Like the ISS, the outpost would be assembled in orbit, piece by piece, module by module. From there, astronauts would travel to and from the lunar surface. NASA’s latest call for designs includes vehicles to move astronauts from the station, down to the lunar surface, and back up. Some of the transportation elements could be refueled and reused.

The companies competing for these contracts will have to build this complex infrastructure in eight years with a fraction of the budget available during the Apollo era. At the Apollo program’s peak, NASA’s budget accounted for more than 4 percent of federal spending. Now it’s less than half a percent. Even with a ballooning federal budget, that still works out to less than half the spending power that NASA had in the 1960s.

There is also another challenge to the administration’s ambitious goals: The rocket that would facilitate access to this floating station is still under construction. So is the capsule that would hold the crew on its journey there. Both programs are running behind schedule and growing more expensive. Last fall, a report by NASA’s Office of Inspector General predicted that the rocket-and-capsule combo won’t be ready for its first test flight, in mid-2020, unless it receives an additional $1.2 billion.

In the midst of all that, NASA also hopes to land robotic missions on the moon. “For us, if we had any wish, I would like to fly this calendar year,” Zurbuchen said, in another show of urgency. The agency picked nine American companies to compete over contracts for the missions last year, and unveiled the payloads—a dozen scientific instruments—this week. It hasn’t mentioned who would fly these missions to the moon. The only systems that would be available by Zurbuchen’s dream deadline are in the private sector, not at NASA.

All together, this is a very tall order. As with most space-exploration ambitions, the timelines for the Trump administration’s lunar plans should be taken with a big grain of moon dust. The U.S. is unmatched when it comes to deep-space exploration—the country has left the solar system twice with the Voyager spacecraft, and has landed on Mars eight times—but its lunar glory days are far behind it. Since the last moonwalkers returned to Earth, NASA hasn’t landed anything on the surface. On top of that, the agency can’t launch its astronauts to the ISS from U.S. soil, and will continue to buy seats for them on Russia’s launch system until SpaceX and Boeing, American companies, can take over the job, a scenario that’s still at least a year away.