What comes after the ISS? Why NASA won’t be building the next space station

The International Space Station is a marvel.

Since November 2000, it has played a constant host to more than 200 astronauts and cosmonauts conducting experiments on everything from X-rays to the effects of extended weightlessness on the human body.

But all good things must come to an end, and as recent air leaks and congressional debates over funding have made clear, the ISS won’t live forever, so NASA is already looking to what might come next in low Earth orbit.

In July, the space agency solicited industry proposals for what it’s calling “commercial LEO destinations,” privately owned and operated space stations to take the place of the ISS, NASA Program Executive for the Commercial LEO Development Program Misty Snopkowski says.

NASA hopes to publish the service requirements commercial space stations must meet by sometime in the spring of 2022. The agency is prepared to award up to four contracts worth a total of $400 million for the first phase of the program at that time.

“We want to be able to have these high-level requirements for industry so that they can come up with their best innovative solutions to meet our needs,” Snopkowski tells Inverse.

Why does the ISS need to be replaced?

The ISS has been flying for more than 20 years and may stay operational into 2030 if Congress agrees to NASA’s request to fund the station beyond the currently approved 2024.

But the station is beginning to show the inevitable wear and tear of decades spent in a dangerous environment, with leaks, near collisions, and parts failures adding up over time.

“We know this thing can’t last forever,” Snopkowski says. “It will have an end date.”

And whenever that end comes, NASA cannot wait around until then to begin the process of replacing it.

“These complex space systems and stations take a really long time to develop,” she says. “We're trying to get that started now so that we have something in place when ISS does eventually have to retire.”

Why do we need a space station?

Given NASA’s ambitious deep space projects, from returning to the Moon within a few years with Artemis, to launching advanced and expensive space observatories like the James Webb Space Telescope, it’s fair to ask if NASA still needs a space station at all.

But according to Snopkowski, NASA scientists still need outposts in low Earth orbit to conduct studies of the science and technology necessary to fly humans into deep space safely.

“Things that have to do with risk reduction, or the effects of the human body in microgravity,” she says. “Especially when you're starting to start to talk about like long-duration missions.”

But NASA doesn’t need to have access to a commercial ISS clone to do those experiments.

What will the new space station plans look like?

In late August, NASA received around dozen proposals its solicitation, according to Snopkowski. While she could not comment on the details of the proposal, “it was a really diverse set of companies that we got proposals from. So small, large, startups, more established,” she says.

The proposals could well include players such as Axiom Space, which already has a NASA contract to build modules for the ISS while it continues its mission, or Bigelow Aerospace, which manufactures compact, inflatable space station modules that could expand to as large as 5,000 cubic meters once in orbit.

Boeing, Lockheed Martin, SpaceX, and others could also be in the mix, and an important thing to keep in mind, Laura Seward Forczyk, founder of space consulting firm Astralytical tells Inverse, is that no one company need duplicate the ISS.

The ISS has been continuously inhabited for more than 20 years, for instance, but “these next commercial space stations may or may not be continuously inhabited,” she says. “It might be that commercial companies have different niches that they want to fulfill, and they find different demand for those.”

Nanoracks, for example, has suggested repurposing the spent fuel tanks from rockets in orbit for robotic manufacturing or satellite servicing operations.

Why is NASA looking for commercial space stations?

The ISS was, in many ways, a diplomatic project to bring about U.S. and Russian cooperation on a post-Soviet era project along with other international partners. It wasn’t built to be optimally cost-effective, Snopkowski notes. Operating the ISS costs NASA around budget around $4 billion annually.

NASA would rather use those limited resources for projects like returning to the Moon and venturing on to Mars, Snopkowski says. The hope buying commercial space station services a la carte could save the space agency a lot of cash. The agency estimates the Commercial Crew program, where SpaceX Dragon space vehicles fly NASA astronauts and supplies to the ISS, will save as much as $30 billion.

“This strategy where we're partnering with industry makes the best sense is from a from a budget perspective,” she says. “These commercial space stations will be owned and operated by these private companies, right, and NASA will just be buying services that they need.”

NASA will set the standards for services and certify commercial space stations for human habitation and safety, Snopkowski says, “but at the end of the day, NASA just wants to be able to be one of many customers.”

What does the future look like without the ISS?

The Commercial LEO Development Program will take place in two phases. Phase One, a design and development phase, will run through 2024 or 2025, according to Snopkowski.

After Phase One, “We would do another full and open competition with industry,” for Phase Two, she says. “That would be for certification and services.”

The aim, Snopkowski says, is to completely wrap up the second phase of the program in the 2028 to 2030 timeframe, just in time for the ISS to take its curtain call, allowing for a smooth transition and handoff of services.

“After the space station retires and we are utilizing these commercial destinations for services, the hope is that we have this robust LEO economy at that point,” she says. “Where there are numerous people that are able to access space — they come there to work, they could play, they could live — and NASA is just one of those many customers that are participating in these destinations.”