With the International Space Station (ISS) speeding toward retirement in the coming years, NASA is looking toward what’s next for manned space operations. With goals spanning into the future that include a permanent presence on the Moon and the eventual manned exploration of Mars, NASA has set its sights on a new address — one that could benefit efforts to reach beyond our own backyard — lunar orbit.

According to NASA, the Lunar Gateway (officially, the Lunar Orbital Platform-Gateway) will offer the best possible bang for the Earth’s space exploration buck. It is to serve as a communications hub between lunar outposts and Earth, supporting lunar operations, advancing deep space science in a way that isn’t possible in low Earth orbit (where the ISS resides), and of course, preparing for future missions that extend deeper into space than our planet’s moon.

There’s just one real problem: the rocket NASA has been counting on to hoist large components of this new space station is meeting with repeated delays. NASA’s Space Launch System (SLS) is set to be the most powerful rocket in history, once completed. It was, however, supposed to start flying last year, and setback after setback has extended that timeline to the point where some have begun to question whether this massive new rocket is worth continuing to develop at all. After all, there is no shortage of private space firms jockeying for opportunities to do NASA’s rocket-work.

Orion, the passenger capsule NASA envisions as the workhorse spacecraft in the era of the Lunar Gateway, is slated to take to the sky for its first mission (Exploration Mission-1) no later than midway through next year. However, it’s becoming increasingly apparent the SLS designed to carry Orion to the stars still won’t be ready in time to meet that deadline. With no other rocket on the planet powerful enough to support the massive weight associated with the EM-1 mission (which includes both the Orion spacecraft and a European Space Agency service module), it seems NASA might be stuck putting all of its major plans on hold due to the perpetually delayed SLS rocket.

However, as NASA officials and lawmakers point out, EM-1 could still launch on schedule, keeping the overall Lunar Gateway mission on schedule, provided they could launch Orion and the European capsule aboard two different commercial platforms.

“I think we, as an agency, need to stick to our commitments,” NASA Administrator Jim Bridenstine said earlier this week. “If we tell you and others we’re going to launch in June of 2020 around the Moon, which is what EM-1 is, then we should launch around the Moon in June of 2020, and I think it can be done. We need to consider as an agency all options to accomplish that objective.”

While the Orion capsule has been test-launched aboard a Delta IV rocket before, NASA isn’t sure how it would go about docking the Orion capsule with the European service module once in space, as these components weren’t designed to do so. But as far as challenges go, that’s less formidable than trying to get into space in the first place.

Once Orion is flying, the process of launching and assembling the Lunar Gateway can begin, which promises to take years in even a best-case scenario. Optimistic predictions from officials like Vice President Mike Pence have suggested that the Lunar Gateway may be ready for a crew as soon as 2024, though based on NASA’s propensity for missing deadlines, that seems rather unlikely.

Like the International Space Station, the Lunar Gateway is also expected to be a truly international endeavor, though unlike the ISS, Canada and the European Space Agency both have a larger stake this time. There would be dramatically reduced involvement from Russia though, which one may attribute to that nation’s financial situation or tensions between Russia and the United States, depending on your politics.

By comparison, current plans for the Lunar Gateway are smaller and include only one Russian module.

“This is an aspirational vision of the Gateway,” Bridenstine said, before adding that this model has the support of the agencies included within it. “Just this morning, I got off the phone with all of our international partners on the ISS, and others, and they are very excited about partnering with us on going to the Moon.”

The fiscal year 2020 budget request released on March 11 calls for $821 million to be allocated toward this endeavor in 2020, adding to the $450 million that has already gone toward its development.