It is a lesson the U.S. space program has had to learn many times over: don’t voluntarily give up a space capability without having a successor ready to go or already operational.
But for the ISS (International Space Station), a gap in LEO (low Earth orbit) scientific research capability will likely not occur when the iconic outpost ends its career, whenever that may be.
And that is in large part due to Axiom, a private space organization with private funding that will begin adding modules to the ISS in 2024 — with the goal that those added modules will then be easily disconnected from the ISS at the end of its life, thus ensuring no gap in low Earth orbit space station capability for the United States.
But making sure there isn’t a gap in LEO station access wasn’t part of the initial equation when Axiom started.
“The only thing I knew how to do when I retired was to build and operate a space station,” said Mike Suffredini, former NASA ISS Program Manager and current President and CEO (and co-founder) of Axiom in an interview with NASASpaceflight.
“At that time, I said I was going to wait for whatever company decided to commercially build a space station. When Dr. Kam Ghaffarian and I started talking, he was very interested in the idea that commercially we could go do that. He came back the next day and said, ‘Okay, I’m in.’”
As Suffredini noted, “At that point, NASA had really not given a whole lot of thought about how we were going to transition. In fact, we had hardly discussed it at all in 2015 except that the government had said, ‘We’re not going to build the next space station. We do need a space station, but we’re not going to build the next one.’”
“While it was understood particularly by the folks we were dealing with that that was eventually going to be a question, we weren’t worried about it quite like that. A few years later, it became really clear that we needed to seriously discuss the end of ISS.”
“Now, we’re working very hard to make sure that gap never occurs. I think the government now is getting to the point where they’re starting to think about it and worry about it. Fortunately, we’re in the right place at the right time.”
So why attach to the ISS if ensuring no gap in LEO station access wasn’t the goal?
“For continuity,” said Suffredini, “the seamless transition from ISS to a commercial platform, no ‘hitches in the get-along.’” In part, this allows investors — both commercial and governmental — who have already allocated resources into the ISS to not have to throw away their technology or re-launch new units to a new space station at the end of ISS’s life.
Some of the components inside ISS can be simply — in relative terms — moved to the Axiom modules before they are detached at the end of the station’s life.
2024 will see the launch of our first Axiom Station module and the arrival of a new destination for breakthrough innovation in low-Earth orbit.
With PDR complete, subsystems in rapid development, and the core structure already in fabrication, the next giant leap is on the way. pic.twitter.com/5SQHWPWJpc
— Axiom Space (@Axiom_Space) November 8, 2021
However, there is an additional utilization benefit for the ISS by first attaching the Axiom modules to the iconic outpost.
“We want countries to utilize ISS,” related Suffredini. “And we want to make sure that the countries that are on ISS are very comfortable with us when we separate.” Part of this comfortability comes not just from utilizing those modules while attached to the ISS, but also in the contractor Axiom chose to build the pressure shells for their modules.
“That’s one of the reasons we used Thales Alenia Space to build our shells. They built 40% of the ISS shells today, so you feel pretty good about it. We build out these shells, we put them on orbit, we operate them; now NASA and the other countries get very comfortable. We know what we’re doing. We built a quality product. We don’t have any problem using them, so all the government work can transition over to us as well. That’s the thought process.”
Additionally, the new Axiom modules will also help meet the station’s ever-growing research demand as well as increase the station’s permanent crew size. “We’re satisfying unmet demand and we’re growing more users, which is a great thing. It also allows us to get used to working together — between us and NASA — as the size of our crew grows and the length of time they stay on orbit expands.”
“Eventually, we’ll have a permanent crew up there as long as our module’s up there,” added Suffredini.
And this scenario is, in part, what led to the first round of Axiom missions that will fly to ISS before the company’s modules begin arriving in 2024.
“The idea of these early missions came up when NASA and Axiom were working together in 2017 to finalize our space act agreement,” said Suffredini. “One of the things the NASA team realized was when we are fully built out, we are going to be able to house eight crew permanently; [now] the ISS can house seven crew permanently. They looked at that and said, ‘We don’t want to have to do that all at once. How about let’s do some flights building up to that point?’”
“So we’ll learn how to work together because, ultimately, we’re going to spend a lot of time attached together.”
But these initial missions evolved.
“Over time, it took on its own life, and that is revenue. We are using private investment, and it’s much easier to get long-term investment if you have revenue already. It’s early revenue, which is important to us. But it’s also the ability to take over demand or to satisfy demand that ISS can’t as we grow new users.”
This business model of only relying on private investment and not taking money from NASA for the development of any of the modules that will be added to the ISS is part of how Axiom has been able to move as quickly as they have in the development process, having already completed the Critical Design Reviews on the pressure shells of the first two modules as well as completing the overall Preliminary Design Reviews of those modules themselves just two months ago.
“NASA’s not paying any money for development. It’s all for data and insight and demonstrations. Fundamentally, because we were free, we didn’t have to wait for NASA to have a bunch of money; we just needed NASA to tell us we could attach to the ISS.”
At present, both modules remain on track for launch to the ISS in 2024 and 2025.
While Axiom Hub 1's primary structure is undergoing welding, core module subsystems are already in various stages of development & testing. Among them is the GN&C suite that will allow the module to autonomously maneuver itself to the ISS when it attaches in late 2024. pic.twitter.com/AvDnUo9JOY
— Axiom Space (@Axiom_Space) October 27, 2021
So what happens when the modules get to ISS? What sort of connections and spacewalks (EVAs, or Extravehicular Activities) will be needed to connect them together and to the ISS?
“When it comes to integration, when we attach to ISS, there is an EVA associated with running the wires from what’s called an MBSU.” The MBSU is a Main Bus Switching Unit — an electrical distribution box that is part of the station’s USOS (United States Orbital Segment), of which NASA, the European Space Agency, the Japan Aerospace Exploration Agency, and the Canadian Space Agency are part.
“We have to run the wire all the way to where the connection is, and then we make that external connection. But after that, [for the other modules after the first] all of our connections are internal. We’re robotically attached, but all of our connections are internal. We won’t have major EVAs to configure our space station, at least not that we imagine today,” noted Suffredini.
This is a highly simplified way of attaching modules together than was previously seen with ISS construction where each module needed to be first physically attached to the station before a series of spacewalks to properly outfit and connect everything together took place.
Much of that had to do with the fact that the ISS was largely designed from 1970s technology when everything was so big there wasn’t enough volume inside to put critical components — therefore necessitating placement of equipment outside. That same equipment — computers, converters, pumps, valves — has now gotten smaller and can now be placed inside.
Another reason so many components are outside of the ISS is due to the use of ammonia as part of the complex’s cooling system. The new Axiom modules will use carbon dioxide instead of ammonia for cooling, thus allowing those systems, aside from the radiators which have to be outside, to be brought inside.
And because numerous components are being moved inside, they no longer have to be space-qualified, meaning off-the-shelf components for cooling systems and quick disconnects and computers will help reduce the cost of the modules while also increasing their ability to adapt to new technologies.
“One of the big challenges on the ISS is, if they’ve got to go rebuild ORUs [Orbital Replacement Units], they have to rebuild the form, fit, and function to fit where they’ve got to go because of the design, particularly outside,” noted Suffredini. “Obsolescence is a huge expense on ISS. We want to avoid that.”
Suffredini related the goal to the everyday use of smartphones. “Your iPhone is a phone, and it’s got a software package on it. You know that when you go buy a new phone, your old software package, all the things you know how to do, will all move seamlessly over to the next one. Part of what we want to do, and we’re challenged to do, is to make sure that’s in our design so that we evolve the platform to stay up with technology.”
But how far can that go? Retrofitting structures on Earth based on technological advancements can be challenging. In space, it can be even more so with an unforgiving vacuum on the opposite side of the wall. So what happens as the Axiom modules age? Each one is designed for a 30-year lifespan based on lessons learned from the International Space Station program and how well those modules have held up compared to initial expectations.
“Every module has its own propulsion system, power system, [and] guidance navigation and control,” noted Suffredini. “That’s important because as modules age, when we get to the point it’s not cost-effective to maintain them anymore or the structure’s gotten to the point we’re uncomfortable with it, every single module that is on our station can be removed. And then we put a new one in its place.”
This also allows for the design to evolve and grow as customer demand evolves.
The AX-1 flight for @Axiom_Space to the ISS will feature 25 experiments with more than 100hrs of human-operated research, a host of Earth observations, & STEM outreach engagements.
— Chris G (@ChrisG_SpX) November 17, 2021
“Long term, the design’s very evolvable, so we expect it to get bigger. The way it gets bigger is going to be based on need. If more and more people want to fly, we need more crew quarters and life support, then the next module we’ll fly up will be for that purpose. If we need more manufacturing space, then we’ll build that.”
“The whole design is evolvable, and as it gets old, we just throw components away and replace them with new ones.”
But expansion can’t happen forever, especially if user needs on the facility begin to conflict.
“We’re going to get to the point where say a manufacturer wants to manufacture a lot of a product. Putting that in a multi-user platform’s not going to be very hospitable either for them or for the other users,” added Suffredini. “Eventually, we envision building separate space stations that perhaps share the same orbit, that are just based a little bit away, so that they can share both the cargo and the crew transportation and reduce costs that way while meeting user needs.”
And that leads to Axiom’s much longer-term plan, to the middle of the century and beyond when the company envisions their platforms being places where people go to work for two to three years at a time and bring their families along as well.
These evolved stations would have rotating structures to provide gravity and living quarters, with the technical challenge being the creation of a station that in part rotates but that also preserves the microgravity environment in other locations.
“That’s where the future is for us,” said Suffredini. “There’s going to be so many users at some point that it’s just going to make more sense to create basically a zip code in space, and it’s big enough for people to bring their families and they can do work there and live normal lives in the ring and do the work in the center section.”
Of course, those are the long-term plans. Far more immediate, the first crewed Axiom flight is set to lift off no earlier than February 21, 2022, from Launch Complex 39A at the Kennedy Space Center atop a SpaceX Falcon 9 rocket and Crew Dragon vehicle.
CORRECTION: A previous version of this story stated that the Axiom-2 mission was scheduled to follow Axiom-1 in Autumn 2022. NASA reached out to NASASpaceflight to clarify that Axiom-2 is not a planned mission at this time but rather that NASA has received proposals for the second and third private astronaut mission opportunities but has not made any selections or announcements.
(Lead image: The free-flying Axiom station with SpaceX’s Crew and Cargo Dragons. Credit: Mack Crawford for NSF/L2)