NASA selects Axiom Space to build commercial space station segment

by Tobias Corbett

NASA has announced that they have selected Axiom Space, an American company headquartered in Houston, Texas, to design, build and launch three large pressurized modules and a large Earth observation window to the International Space Station (ISS).

This partnership between NASA and Axiom is issued under Appendix I of NASA Next Space Technologies for Exploration Partnerships 2 (NextSTEP-2) public-private partnership program which the agency hopes will help stimulate commercial development of deep space exploration capabilities.

Appendix I of NextSTEP-2 was originally issued on June 7th 2019 and called for private companies to bid to develop habitable commercial modules, to be built and launched to the International Space Station, and then attached to the forward end of the station as part of NASA’s long term plan to open up the ISS to large amounts of commercial opportunities.

Axiom plans to launch three large modules and an Earth observation window (much like the Cupola currently on the ISS) to the Station to form the “Axiom Segment”, with the first module launching in the second half of 2024.

According to a press release from Axiom, the three modules that make up the Axiom Segment will be divided into a node module, a crew habitat and a research and manufacturing module, plus the large window.

No details on the order of launch have been outlined yet, although it can be assumed the node module will launch first.

Rendering of what the “Axiom Segment” might look like – Via Axiom Space

Although Axiom is a relatively young company, having been formed only four years ago in 2016, there is no lack of experience within the company’s ranks.

Axiom’s Co-founder and CEO is Michael Suffredini, who formerly worked at the Johnson Space Centre (JSC) as the program manager for the International Space Station project.

The Axiom team also includes Michael Lopez-Alegria, a former NASA astronaut who flew on the space shuttle three times and commanded the 14th Expedition to the ISS, as well as former shuttle commanders Brent Jett and Charles Bolden, the latter of whom served as NASA’s 12th administrator from 2009 to 2017.

Axiom is also working alongside several companies with extensive experience with the ISS program, this includes Boeing, who has made several of the modules that make up the US Segment, including Node 1 and the US Laboratory Module. Axiom is also working alongside Thales Alenia Space, Maxar Technologies and Intuitive Machines to get this project off the ground.

Not many details of the partnership, including a specific timeline or costs involved, have been released to the public yet.

In a press release from NASA regarding the partnership with Axiom, it is stated that “NASA and Axiom will next begin negotiations on the terms and price of a fixed-price contract with a five-year base performance period and a two-year option” which indicates that these details have not been completely ironed out yet and these details should come to light as NASA and Axiom move forward with this partnership.

Axiom Space Render of the ISS with their modules, from distance.

Not many details of the modules that will make up the Axiom Segment, besides what they are named have been made known to the public yet aswell. Over the years Axiom has released renderings of what the Axiom segment could look like, although next to zero details on anything regarding the specifics on the module’s size, habitable space, if it will have its own propulsion system, how it will be powered or what launch vehicle it will use to be launched toward the station have been made known to the public.

Again, like with before, these details will most likely come to light as NASA and Axiom move forward with the upcoming plans.

One thing that is known for sure is that the segment will be attached to the forward docking port of the Space Station’s Node 2 module, as outlined by Appendix I of NextSTEP-2. Node 2, also known as Harmony, was delivered in October 2007 onboard space shuttle Discovery as part STS-120, since then it has become one of the most important parts of the US Segment of the Space Station.

Space Shuttle Atlantis docked to the forward docking port on Node 2, where the Axiom module is planned to be located. – Via NASA

Some minor relocation of the equipment attached to Node 2 will be needed before the first Axiom module can take its place on Node 2’s forward port. The module is currently attached to the forward docking port of NASA’s Destiny Laboratory module, where it will stay for the foreseeable future. The module itself has four permanent pieces of hardware attached to it and one open docking port. 

Attached to the Node’s port side is the main pressurized section of the Japanese Experiment Module, also known as Kibo. To the starboard side is the European Space Agency’s Columbus laboratory module. On the module’s zenith (Space-facing) docking port is Pressurized Mating Adapter 3 (PMA 3), a docking port intended to be used by NASA’s contracted Commercial Crew Vehicles when they come online sometime this year.

There are no permanent modules attached to Node 2’s nadir (Earth-facing) docking port, although it is commonly used for uncrewed resupply vehicles like JAXA’s HTV, SpaceX’s Cargo Dragon or Northrop Grumman’s Cygnus.

The only piece of hardware that needs to be moved is PMA-2, which currently occupies Node 2’s forward docking port, and will need to be moved to make way for the first part of the Axiom segment. It is currently unclear whether PMA-2 will be moved onto the Axiom segment or moved to another part of the ISS entirely.

The first Axiom module would also be the first large pressurized rigid module on the station’s US Segment to not be delivered by the space shuttle.

The last large rigid module to be delivered to the US Segment was The Permanent Multipurpose Module (PMM), which was delivered in February 2011 onboard Shuttle Discovery on STS-133. Since the shuttle has now been retired, the modules that make up the Axiom segment will most likely be launched on conventional rockets, and make their way to the station and then dock either under their own power or via a “space tug”, much like how the Russian’s have delivered module’s to the ISS or their previous station “Mir” in the past.

This is quite different from how the rest of the US Segment was assembled, with module’s launching in the shuttle payload bay, then being carefully taken out of the payload bay and being moved into place by the shuttle’s robotic arm or the space station’s robotic arm. 

Although no large additions have yet been made to the US Segment without the use of the shuttle, it isn’t an unheard-of concept. In 2010 NASA was considering launching a 4th Node module to the ISS sometime around 2013/14. Node 4 never ended up being launched but several concepts on how to get the thing to the station without a shuttle were drawn up.

Diagram showing how Node 4 may have been launched to the ISS.

Node 4 would have been launched on either an Atlas V or Delta IV rocket along with an expendable “space tug” which would carry the propulsion and other various systems that would be necessary to get the module to the ISS, once the module was docked to the station the tug would be detected and left to burn up due to atmospheric friction.

If the Axiom modules have no built-in propulsion systems it can be expected a very similar method of delivery will be used by Axiom, although nothing is confirmed yet.

The Axiom segment will also allow Axiom to go ahead with plans to train and fly paying customers to the ISS. In a newsletter released in November, last year Axiom confirmed that they had signed a deal worth $55 million with a space tourist hopeful in January 2019 and were still working with more candidates for orbital missions. Axiom plans to fly paying customers to the ISS two to three times a year.

Axiom has also confirmed that they plan to separate the Axiom segment from the ISS once it nears the end of its life. They have stated that they plan to launch a “Large Power Platform” to the Axiom segment before this happens, then separate the segment from the station to act as its own individual station called “Axiom Station”.

Rendering showing how Axiom’s “Axiom station” may look. – via Axiom Space

The Power Platform will make up for all of the capabilities the ISS provides that will be lost when the Axiom segment becomes Axiom station, like power generation, cooling systems, etc.

Once Axiom station begins operation Axiom Space will continue missions contracted for paying customers at the same rate of two to three times a year.

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