Commercial industry gears up for ISS replacement around 2030 amid concerns

NASA and the commercial space industry are planning for the eventual replacement of the International Space Station (ISS), which is currently set for 2030. Companies like Axiom and VAST have already started construction on the first modules of their planned commercial stations, while others are also planning to offer commercial station capability in the future. However, questions have arisen about the viability of the market for low-Earth orbit human space stations.

Last week’s announcements by VAST regarding its initial space station — which is scheduled to be launched next year — as well as its follow-on space station are the latest developments in the commercial space station space. Meanwhile, Axiom reworked its space station design, which is also being built. Other companies like Blue Origin and Voyager Space are also working on station concepts, though it is unclear how many of these projects will make it to low-Earth orbit.

NASA’s Commercial LEO Destinations (CLD) program is assisting the commercial sector in developing replacement space stations to fulfill the research functions that ISS performs today. As former NASA Administrator Jim Bridenstine famously stated, NASA’s goal is “to be one of many customers” procuring services in low-Earth orbit.

Rendering of what the “Axiom Segment” might have looked like under the original design. (Credit: Axiom Space)

During Bridenstine’s tenure, Axiom Space was awarded a $140 million maximum value fixed-price contract to attach at least one habitable commercial module to the International Space Station. This contract was announced on Feb. 28, 2020, and Axiom was selected under NASA’s Next Space Technologies for Exploration Partnerships 2 Broad Agency Announcement (NextSTEP), which was a precursor to CLD.

NASA formally created the CLD program in March 2021. CLD was created to support the creation of commercial space stations in low-Earth orbit, with NASA being a customer instead of the owner and operator. This followed on the heels of the Commercial Crew Program and Commercial Resupply Services programs which had successfully taken over crew rotation and cargo supply missions to the ISS.

Three teams were selected in the first phase of the CLD program in December 2021. A Blue Origin-led consortium, with Sierra Space, Boeing, and Redwire was awarded a funded Space Act Agreement (SAA) worth $130 million to develop its Orbital Reef concept.

Artist’s rendition of the Orbital Reef space station. (Credit: Blue Origin)

Voyager Space, Nanoracks, and Lockheed Martin were granted $160 million to develop the Starlab concept, while Northrop Grumman and Dynetics were granted $125.6 million to develop their station concept. Additional companies received unfunded SAAs to assist in their station development programs.

For the second phase of the CLD program, NASA plans to purchase space station services from the commercial sector, including crew time and cargo deliveries. One or more awards for Phase 2 are expected in 2026 and NASA hopes for a two-year overlap between CLD operations in 2028 and ISS retirement in 2030.

Several companies — or consortiums of aerospace companies — are competing for Phase 2 awards and the chance to host NASA astronauts and station operations after the ISS is retired and deorbited. The winner — or winners — of Phase 2 contracts likely will be one of four station designs currently under development.

Axiom Station as planned with four modules before recent financial issues came to light. (Credit: Axiom Space)

Axiom Space

Axiom Space’s Axiom Station project has been underway since the NextSTEP announcement, with its first module scheduled to dock with the International Space Station in late 2026. Thales Alenia Space is welding and machining the first module, named AxH1. According to the company,  it will soon be sent to Houston for final assembly and integration.

The original plans called for three more modules to dock to AxH1 later. Following this, the complex would undock from the ISS and begin an independent life as a free-flying commercial space station.

However, Axiom Space is facing financial issues and a shakeup in its leadership. Former NASA ISS program manager Mike Suffredini, who helped found Axiom Space in 2016 with billionaire Kam Ghaffarian, left the company’s CEO position on Aug. 9. Personal reasons were cited for the departure, though the company was also having cash flow issues and layoffs. Ghaffarian serves as interim CEO until a permanent successor is named.

A section of the AxH1 module in work at Thales Alenia Space. (Credit: Axiom Space)

As a result of these issues, the Axiom Station is believed to have been downsized to two modules from the originally planned four. There will be a reduced research capability from this arrangement compared to what was expected. However, it remains to be seen if additional capability can be added after the station becomes operational.

The AxH2 module was the next planned addition to the fledgling space station, and it incorporates additional living space and research capability. The next element in the original plans was the AxRMF research and manufacturing module, followed by the AxPTM power thermal module. This module contains solar panels and extended life support, environmental, storage, and payload capabilities.

The AxH1 module is set to fly aboard a heavy lift rocket, with New Glenn and Falcon Heavy as possible choices. Falcon Heavy is flight proven, whereas New Glenn has yet to make its first test flight. When and whether the AxH1 module flies will determine the schedule for the second module to fly, as Axiom deals with issues like a $670 million payment due to SpaceX for its Axiom Crew Dragon flights.

Axiom is also working on a space suit for lunar use, with a $228 million contract to develop suits for Artemis astronauts. The recently unveiled spacesuit to be used on Artemis III and subsequent flights to the Moon — developed in cooperation with Prada — is a higher, more immediate priority for NASA.

Artist’s impression of a commercial astronaut looking out the window of the Haven-1 space station. (Credit: VAST)

VAST

The company known as VAST is another entity working on a commercial space station. Founded in 2021 by Board Chair & Tech Fellow Jed McCaleb, VAST was created to develop artificial gravity space stations to allow people to live and work in space without the side effects of living in microgravity.

In May 2023, VAST announced its first space station and first crewed mission. The Haven-1 single-module space station would be launched no earlier than August 2025 atop a SpaceX Falcon 9 to low-Earth orbit. Haven-1’s launch would be followed by the Vast-1 Crew Dragon mission, which would send four people to Haven-1 for a 30-day stay.

The Haven-1 space station is a single cylinder 10 meters long and nearly four meters wide, outfitted with solar panels generating approximately 1,000 watts of power. Haven-1 is equipped with a research facility with 10 middeck locker equivalent payloads slots, which are around the size of a microwave and function as spaces for experiments. The station is also meant to be capable of supporting artificial lunar gravity through spinning.

Cutaway diagram of the final design of Haven-1. (Credit: VAST)

Haven-1 will be equipped to use the Starlink network for broadband access, making it the first commercial space station to use the network. The station’s final design was announced this month, and its interior was designed using lessons learned from the ISS. Haven-1 will become the world’s first commercial space station when it flies.

Before Haven-1 launches, a pathfinder vehicle is scheduled to fly earlier in 2025. The Haven Demo mission will test hardware and software to fly on Haven-1. After Haven-1 and Vast-1 are launched, other missions are expected to fly to the station. Haven-1 is to be followed by Haven-2 if it is selected by the NASA CLD program in 2026.

VAST CEO Max Haot unveiled Haven-2 on Oct. 14 at the International Astronautical Congress in Milan, Italy. Haven-2’s first module, nearly six meters longer than Haven-1 and with greater habitable volume, is scheduled to launch in 2028 aboard a Falcon Heavy, with completion of the full station expected in 2032. The core module with a diameter of seven meters is to be launched in 2030 aboard Starship, after the first four modules are launched.

Rendering of the complete Haven-2 space station. (Credit: VAST)

The full Haven-2 station will consist of the core module and eight additional modules. An airlock will be included in the core module to allow for spacewalks, and a cupola larger than the one aboard ISS is also planned. There will be no capability for artificial gravity, as Haven-2 is meant to meet NASA’s requirements for microgravity research. Crew and cargo will depend on what commercial capabilities are available.

Orbital Reef

Blue Origin, along with partners Sierra Space and Boeing, announced the Orbital Reef space station in October 2021. NASA awarded Blue Origin $130 million in a funded SAA for space station development that December. This was one of three SAAs awarded in the first phase of the NASA CLD program.

Blue Origin and Sierra Space ran into issues with their relationship for the project; these issues became public in October 2023. No hiring was being done in the project at the time due to other projects being higher priorities and there was talk about both companies possibly parting ways.

Sierra Space’s LIFE module prior to a burst test at the Marshall Space Flight Center. (Credit: Sierra Space)

However, this has not happened, and Blue Origin passed four test milestones relating to Orbital Reef in March 2024. In addition, Sierra Space successfully passed burst testing on its Large Integrated Flexible Environment (LIFE) modules in the summer of 2024. These modules will be used as habitats on Orbital Reef.

Orbital Reef’s current design features three LIFE habitats, along with three core modules, five additional modules, and a truss with solar panels. This station is designed with 830 cubic meters of internal volume, 90 percent of the internal volume on the ISS, and will have a crew of ten in its final configuration.

The Starliner and Dream Chaser spacecraft have been proposed as the crew and cargo vehicles for Orbital Reef, though the issues faced by Starliner on its Crew Flight Test mission have delayed its use as a crew rotation vehicle for the ISS. Starliner is now off of the 2025 crew rotation manifest, and Boeing has lost money on the program. Questions remain about when and even whether Starliner will fly again.

Dream Chaser Tenacity attached to its Shooting Star cargo module. (Credit: Brady Kenniston for NSF)

Dream Chaser is currently only designed as a cargo vehicle, and it expected to fly in 2025. If Starliner is unable to proceed as a program, a replacement vehicle for crew rotation will be needed, and it remains to be seen when and whether Orbital Reef will fly. If Orbital Reef elements are launched, they would fly aboard the upcoming New Glenn launcher, which is at this time being prepared for its first test flight.

Starlab

Nanoracks, Voyager Space, and Lockheed Martin proposed a space station known as Starlab in late 2021, when the consortium received its funded SAA. The Starlab project has continued since then, albeit with Airbus Defence and Space replacing Lockheed Martin as a member of the consortium. Northrop Grumman ended its own effort to develop a space station and joined the consortium.

To design and build the station, Voyager Space and Airbus formed Starlab Space LLC in January 2024. Starlab’s CEO is former NASA astronaut Tim Kopra, who flew on two Space Shuttle flights, launching on STS-127 and landing on STS-128. Kopra also launched to the ISS in 2016 aboard Soyuz TMA-19M and spent 186 days in space.

Starlab consists of two modules, one of which is an eight meter wide habitation and laboratory module with docking ports. The other module is a service module with solar panels and propulsion elements. The station is designed to have the same payload volume as the ISS, but only half of the internal volume of the ISS, totaling 450 cubic meters while the ISS has 900 cubic meters of internal volume.

Rendering of Starlab in orbit. (Credit: Starlab Space)

The consortium chose SpaceX’s Starship as the launch vehicle to fly Starlab into orbit in one single flight and launch is scheduled at present for 2028. Starlab will be resupplied by Northrop Grumman’s Cygnus cargo spacecraft.

Risks to NASA’s human presence in Earth orbit

While the commercial space sector is busy working on various concepts to replace the capability that the International Space Station offers, questions have arisen about the possibility of continuing a human presence in orbit without at least a short term gap between the ISS and a new commercial station.

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Capital for the commercial space sector is harder to come by than it was during the time of low interest rates prior to the COVID-19 pandemic. Axiom Space’s interim CEO Kam Ghaffarian has recently stated his belief that the market was not large enough for more than one commercial station, as his company has struggled with raising capital.

One notable company involved in the commercial station space for two decades has already ceased operations. Bigelow Aerospace, founded in 1998 by hotel chain owner Robert Bigelow, developed station designs based on NASA’s Transhab inflatable module research and even flew three prototypes. One of these prototype modules, BEAM, is still docked to the ISS. However, the company folded during the COVID-19 pandemic in 2020.

Bigelow’s Genesis I inflatable station module prototype, launched in 2006. (Credit: Bigelow Aerospace)

There is also a risk to the International Space Station that could impact NASA’s human presence in low-Earth orbit. Cracks have developed in a tunnel between the aft docking port of the Russian segment’s Zvezda module and its pressurized interior, causing air leaks. NASA classified the air leaks as a high consequence and high likelihood risk.

The Russians could permanently close the hatch between Zvezda’s pressurized interior and the docking port, but that would reduce the number of ports available on the Russian segment from four to three. NASA does not rule out extending the ISS past 2030 should the commercial sector not be ready by then, but the Station’s aging hardware, international politics, and NASA’s general funding situation will need to be considered.

The Zvezda module, as seen by the STS-97 astronauts in late 2000. (Credit: NASA)

NASA deputy administrator Pam Melroy, herself a former Shuttle astronaut, recently made remarks during the International Astronautical Congress questioning the definition of “continuous human presence” in low-Earth orbit. “Is it a continuous heartbeat or a continuous capability,” she asked before noting that there were conversations about that in the agency.

There has been a NASA astronaut in orbit every day since Oct. 31, 2000, and the International Space Station has hosted important research to benefit Earth and humanity during the first two decades of the 21st century. As the aging ISS flies toward retirement, uncertainty remains as to when the commercial sector will be able to replace its capabilities.

(Lead image: Artist’s impression of the VAST Haven-1 space station with a Crew Dragon docked to it. Credit: VAST)