A New Era of Private Space Stations


For the past several years, there has been much hullabaloo regarding proposed private space stations. Yet several current proposals seem much more substantive than chiefly aspirational proposals in the past. That the International Space Station (ISS) has less than one decade of expected life remaining has accelerated both investment as well as government interest and funding. Reduced launch costs provide a further foundation for  the tangibility of such proposals.

The meaning of “private” is rather muddled. Parts of the International Space Station have been build by private firms, yet no one would call the government-operated ISS private. Yet, extensive government funding for a space station is insufficient to overcome the private descriptor. That a station will be owned and operated by private firms, despite chiefly being funded by governments is apparently sufficient for the private descriptor, even though governments are still on the hook for funding and legal liability for possible damages caused by that station.

There have been numerous proposed private space stations that failed for lack of funding and other reasons. However, with ISS reaching the end of its lifetime, and with governments setting their sights closer towards the Moon (e.g. the Lunar Gateway station), there has been strong impetus by G7 governments to strongly encourage (with funding and friendlier policies) the development of one or more private space stations in low Earth orbit. This isn’t Apollo-sized funding, which has been reserved instead for the Space Launch System (SLS). A “new space” approach might be able to lower the cost of such a station from hundreds of billions of dollars to just several billion, and perhaps even hundreds of millions for the initial core elements (propulsion, power, habitat). Despite the caveat that most of this will be government-funded, it is a time of exciting possibilities.

There are several proposed private space stations that already have potentially awarded funding in excess of $100 million. Nevertheless, there are many plans for private space stations. This article will review them, and discuss their status and key scenarios for the next several years.

What’s Up There Now?

There already are human-tended private “space station” facilities already in space, attached to ISS. Bigelow Aerospace provided an actual inflatable BEAM module to the International Space Station. It was used for testing and storage, but it worked and is still in orbit, though Bigelow as an enterprise has substantially reduced operations. Nanoracks has sent up the Bishop airlock module to ISS. It includes an airlock and room for experiments. It is operational and Nanoracks is a lively venture. It’s not a space station, but this technology could become part of a private space station.

What Could Be Up There Soon?

Axiom will be sending a private, substantially NASA-funded module to ISS. This module could be detached from ISS to form an initial module of a stand-alone private space station.

What Could Replace ISS?

It is expected that that ISS will endure operational until 2024 and hoped to remain operational until 2030. So which proposed standalone private space stations could credibly be in orbit within the next two to seven years? What will be the characteristics of those stations. Of special interest to Sustainspace, what novel and advanced life support technologies or approaches will be utilized?

While acknowledging the many proposals over the years for private space stations, we will examine well-funded current proposals. Well-funded generally means at least $100 million has been potentially awarded in private investment and government contracts. Some of the government funding has been awarded under NASA NextSTEP programs, covered previously by Sustainspace in Space Habitats for Lunar Gateway.

Axiom Station

NASA awarded Axion Space a NextSTEP I contract for an ISS module in February 2020 with a maximum potential value of $140 million. Although Axiom was not awarded an independent space station contract, this module could possibly be detached in the future as part of own standalone space station.

The proposed Axiom standalone space station has a “crew quarters + research and manufacturing capabilities … A late 2025 launch of the first section” is projected” (Axiom).

Major Elements
  • Hab One
  • Hab Two
  • Research & Manufacturing Facility
  • Power Thermal Module
Further information


Series of space station assemblies

Axiom space station Infographic (credit: Axion Space)

Orbital Reef

The Orbital Reef space station is being proposed by a consortium of aerospace companies, lead by Blue Origin. NASA awarded Blue Origin $130 million under the agency’s Commercial Low-Earth Orbit Destination program to “formulate and design commercial low-Earth orbit destination capabilities suitable for potential government and private sector needs” (NASA 2021). NASA awarded the agreement in December 2021″. https://www.orbitalreef.com/news/sdr-milestone

Orbital Reef has passed its system definition review by NASA (see also . The target is for Orbital Reef to be in Earth orbit in second half of this decade.

Chief Partners
  • Blue Origin
  • Sierra Space
  • Boeing
  • Redwire
Further information:


multi-module space station above Earth

Orbital Reef space station (credit: Sierra Space)


The Starlab space station is proposed by a partnership of aerospace companies lead by Nanoracks and Lockheed Martin. Nanoracks already has the Bishop Airlock module in orbit attached to the International Space Station. Lockheed has already developed the Orion human space capsule.

NASA awarded Nanoracks LLC $160 million under the agency’s Commercial Low-Earth Orbit Destination program.

  • Nanoracks
  • Voyager Space
  • Lockheed Martin
Major Elements
  • Power/propulsion
  • Airlock module
  • Inflatable module
Further Information:


space station with solar arrays and inflatable module

Starlab space station (credit: Nanoracks)

Northrop Grumman station

Northrop Grumman’s proposed space station is unnamed, but it could be a variation of Northrop Grumman’s Lunar Gateway power and HALO core modules with later additions.

NASA awarded Northrup Grumman Systems Corporation $125.6 million under the agency’s Commercial Low-Earth Orbit Destination program.

“The station will have the ability to support four permanent crewmembers initially, with plans to expand to an eight-person crew and further capability beyond that. The station is designed for a permanent presence of 15 years.” (Northrup Grumman 2021)

Despite being a traditional aerospace contractor, Northrop-Grumman is very down to business. In essence, they will be building two stations (Lunar Gateway and LEO), so there should be some economies of scale and reuse of know-how and IP. This endeavor is positioned on their website as more of a “pay-to-spay” facility rather ran an aspirational venture for the love of space. Hence the usual details (such as planned modules) aren’t well-publicized. Yet if they get continued funding, bets are on that they will deliver.

  • Northrup Grumman
  • Thales Alenia Space (possible, based on Lunar Gateway)
  • Maxar Technologies (possible, based on Lunar Gateway)
  • Crew quarters
  • Science
  • Up to six docking ports
Further Information
  • https://www.northropgrumman.com/space/commercial-space-station/
Space station comprising cylindrical modules and solar arrays

Northrup Grumman space station

Other Possibilities

There are a few “under the radar” possibilities for private space stations to be in orbit in the next few years.

SpaceX Starship

Over in left field, the SpaceX Starship could provide enough volume in space to match that of ISS. There are no published plans to use Starship as a private LEO space station, but if other endeavors fail, it would not be surprising for Starship to fill in, relatively quickly, if the US government is willing to pay for it.

Sierra Space Dreamchaser + Shooting Star module

Somewhat under the radar, and originally billed as a Dreamchaser cargo attachment, Shooting Star can also function as a standalone outpost. The Defense Innovation Unit has contracted with Sierra Space to use Shooting Star as an unmanned space outpost. It can be pressurized. A Shooting Star in combination with a Dreamchaser spacecraft could function as a modest space station.

Whimsical? Blue Origin—Orbital Amazon Distribution Center

Will Blue Origin place an Amazon distribution center in orbit? Highly desired products could be rapidly delivered in small landing capsules to anywhere in the world for those willing and able to pay. When will this happen? Keep a careful eye on those Amazon order delivery options!

STEM Growth Chamber Project

Arduino and battery atop a cube containing plants

STEM Plant Cube version 1.0


The known Universe is 92 billion lightyears in size. Yet, ironically, volume available for plant experiments in space is often limited to mere centimeters. This presents a challenge for growing plants in space for food, research and other purposes.

Consequently, inspired by the cube sat movement, SustainSpace has been developing a suite of 1U–2U cube form plant growth chambers involving minimal volume and mass. Ultimately intended for space research, SustainSpace is also developing an inexpensive STEM version for educational use on Earth, using “off-the-shelf” components.

A goal of this project is to introduce students to concepts related to growing pants in space, such as inputs and outputs, constrained volume, sensing and controlling. Another goal is to eventually produce a chamber that is better optimized to actually grow plants.

Version 1.0

Sustainspace has developed version 1.0 of the STEM version chamber. This version is a baseline STEM chamber intended to demonstrate key concepts and be relatively simple to construct. It requires no soldering, but patience is helpful.

It contains colored LEDs for illuminating plants and signaling growth direction and several. It is built around a 1U (10 cm^3) translucent plastic frame. In one configuration, plants are contained in open air in a pullout square petri dish tray, but could be placed in other enclosures (sealed or open air).

An Arduino controls multicolor LEDs and monitors temperature and humidity sensors. Data transmission is through a cable attached to a computer. However, the chamber LEDs can be operated by connecting a simple 9 Volt battery to the Arduino. LEDs are pulsed to provide red light to give the plants energy (via photosynthesis) and blue light to communicate desired growth direction.

This version is not intended to provide the necessities of growing plants, aside from a small proportion of required light. The 1U frame is translucent with large openings to allow air and light to enter the cube. The plants will also need to be watered. This chamber is only 10 cm tall, so plants may periodically need to be trimmed to fit inside.

Our baseline test plant is chives. They can germinate in a media-filled petri dish and grow in the chamber. Periodic trimming provides a nice food garnish. If protection against evaporation is provided, the chives can be neglected for weeks, allowing them to survive school breaks. A square petri dish can slide in and out of the chamber like a drawer. For simplicity, soil can be used as the root media, but gel and netting can be used if the chamber is rotated to simulate microgravity.

Plant cube with chive plants and blue LEDs

STEM Plant Cube version 1.0 with chive plants and blue LEDs

For further information, please see the Project Page.

A New Frontier In Life Support with the I-HAB

Cylinder module with solar cell wings

I-HAB module (Credit: ESA)

I-HAB, a seldom-discussed component of the Lunar Gateway, could have an out-sized impact on the advancement of life support systems. This module is chiefly devoted to human habitation and life support. It is being developed primarily under the auspices of the European Space Agency who has devoted significant resources towards the development of closed-loop life support. Therefore, discussion of this module deserves to be revisited.

Lunar Gateway

The Lunar Gateway (also called the Cis-Lunar Gateway, or simply Gateway) will be the first microgravity deep space habitat for humans. It will introduce humans to space environmental factors for much longer periods than past lunar missions. The Gateway is being developed by NASA, the European Space Agency (ESA), JAXA, and the Canadian Space Agency (CSA).The Gateway will comprise several modules.

The Lunar Gateway conceptually began as the Deep Space Gateway, and was originally a stand-alone destination for the Space Launch System mega-rocket and the Orion capsule. After the advent of the Artemis program, the gateway was renamed the Lunar Gateway and has a support role for the Artemis program. One role would be to serve as an assembly point for a lunar landing spacecraft requiring components from multiple launches. (Note: not all Artemis proposed scenarios require assembly).

The core module of the Gateway is the Halo module. Halo will provide basic life support and environmental control capabilities, but will be extremely barebones. It is just good enough to sustain humans at the minimum level as long as supplies last. It is being constructed and will be launched under an extremely tight timeline (subject to funding).

Arrangement of Gateway components

Gateway configuration (credit: ESA)


In contrast, the International Habitat (I-HAB or iHab) module will explore sustainability in deep space. It may contain some closed-loop capabilities. “I-HAB is ESA’s contribution of an infrastructure element supporting the Gateway with full crew habitability and utilization requirements from early 2026. I-HAB includes contributions from USA, Japan and Canada Space Agencies.” (ESA I-HAB Industry Day Invitation).

I-HAB is being built by Thales Alenia Space company and a consortium of other companies. “The company has just signed a first tranche contract with the European Space Agency (Esa) of €36m (£32m) to begin work on iHab (the eventual, full contract will be worth €327m/£295m).” (BBC News).

“iHab will have room for four astronauts to comfortably move around. It will require all the additional equipment needed for life support, and carry protection against micrometeorite impacts – and the increased radiation that exists when moving away from Earth.” (BBC News).

Room with astronaut and equipment

I-HAB interior mock-up (credit: Thales Alenia Space)

It is possible that I-HAB will eventually contain an astroculture component to supply fresh food for long duration missions and for research in the deep space environment. Characteristics of that environment include the forces of the cis-lunar orbit and a wider variety of radiation than that received at the International Space Station in low-Earth orbit. “The I-HAB will experience for the first time long exposure in the deep space environment, offering the opportunity to test and prove potential design solutions for protection against cosmic radiations.” (Thales Group).

SustainSpace will continue to delve further in the details of I-HAB as they become better known.


NASA CSA Deep Space Food Challenge

crescent moon with corn and spoon

NASA CSA Deep Space Food Challenge

NASA and the Canadian Space Agency (CSA) are inviting organizations and teams of individuals the Deep Space Food Challenge invites teams to create novel and game-changing food technologies or systems that require minimal inputs and maximize safe, nutritious, and palatable food outputs for long-duration space missions, and which have potential to benefit people on Earth.

This is an international competition. NASA and CSA are offering hundreds of thousands of dollars of cash challenges, and others can get the glory of recognition.

This is an exciting opportunity to get involved in space life support development. The challenge is administered by the Methuselah Foundation, which describes its mission to accelerate breakthroughs in longevity. It was co-founded in 2001 by David Gobel and Dr. Aubrey de Grey.

There are deadlines for registration, entry and milestones, so please see the Deep Space Challenge website for further information for requirements, eligibility and timelines.

Nanoracks StarLab AgTech Space Farming Center

Spacestation module with cube greenhouses attached

Rendering of greenhouses mounted externally to the Nanoracks Bishop Airlock on the ISS. Credit: Nanoracks / Mack Crawford

The Abu Dhabi Investment Office (ADIO) has announced that they are partnering with Nanoracks via their Agriculture Technology (AgTech) Incentive Program, an effort that supports the development of cutting-edge programs to boost the emirate’s AgTech capabilities and promote innovation.

AED 152 million (USD 41 million) of incentives from ADIO will allow Nanoracks to build the StarLab Space Farming Center in Abu Dhabi as an AgTech commercial space research center. The Center will be focused on advancing knowledge and technology about organisms and food that are produced in the harsh and alien environment of space. Nanoracks is seeking through innovations in space-based AgTech to solve key food sustainability challenges on Earth, mostly caused by climate change, which can help to ‘green the desert.’

Allen Herbert, SVP of Business Development and Strategy, and Head of Nanoracks, UAE, said: “Much of today’s technology used for vertical, urban and closed environment agriculture initially came from space research from 30 years ago, and Nanoracks is ready to synergise these technologies back to in-space exploration.”

A press release for the Center shows plants growing in Nanoracks’ proposed StarLab Outpost module shown below. Nanoracks proposed this same module as a core and habitation unit for NASA’s Lunar Gateway for the NextSTEP 2 deep space habitat competition (see our Space Habitats for Lunar Gateway story).

module with rows of plants inside

Rendering of greenhouses inside proposed StarLab Outpost. Credit: Nanoracks / Mack Crawford

US-based Nanoracks, the single largest commercial user of the International Space Station, opened its first UAE office in Abu Dhabi’s global tech ecosystem, Hub71, in 2019.


Space Habitats for Lunar Gateway

Long, box-like interior with astronauts

iHab interior (credit: Vienna Region)

Original raisons d’être for the Lunar Gateway were to study long-term human endurance and sustainable life support in a deep space environment, and prepare for missions to Mars and the asteroids. The Lunar Gateway was renamed the Deep Space Gateway as part of the big push for the Artemis program.

What is the current state of plans for life support and space habitation on the Lunar Gateway? Some background is in order. Several years ago, NASA created the NextSTEP program to support crewed space exploration. In 2014, NASA’s NextSTEP program awarded contracts to several firms to expand habitation and other capabilities of the Orion space capsule. The total amount awarded for life support and habitats was about $5.5 million. NextSTEP 2 was more ambitious, funding concept studies and the construction of entire prototypes for deep space habitats. Contracts of about $10 million per awardee were awarded for 24 months of work, for a total amount of $65 million for work over 2016-2018. Awardees (current names) were Lockheed Martin, Northrup Grumman, Bigelow Aerospace, Boeing, Sierra Nevada and Nanoracks. Their visions for space habitats are shown below. (Bigelow has substantially scaled back operations since then.)

Six proposed space habitats

NextStep 2 Contract Awardees, Proposed Habitats and Differentiators. Credit: NASA.

NextSTEP 2 was a prelude for the competition for the initial Lunar Gateway space habitat module called the Habitat And Logistics Outpost module (HALO). Then on 5 June 2020, an initial $187 million contract was awarded to Northrup Grumman for the HALO module for the Lunar Gateway, which was targeted for launch by 2023 (NASA, 2020). It was felt that Northrup Grumman’s existing Cygnus cargo vehicle (used for the International Space Station) was proven technology that would allow for faster development and an earlier launch. 

Plans for HALO have gone through several iterations. It is still a habitat, but probably now it also has broader capabilities since it may be the only crewed module for awhile. The contractor for HALO Habitat And Logistics Outpost module (HALO) will almost certainly receive considerable additional funding. A ball park estimate would be at least US $1 billion for just the habitat (even if “new space” economies are invoked) and possibly several billion. This does not include funding for the propulsion or energy systems, which have been awarded to Maxar.

Two stubby, cylindrical modules.

iHAB and HALO module concepts. Note: launch years have changed. Credit: NASA.

The HALO module is really just a place for astronauts to transfer to the Moon. It does not meet the earlier goals to test human endurance and sustainable life support in deep space. However, the Lunar Gateway is planned to have a second space citation module called iHab, which supposedly will have long-term, sustainable life support capabilities. International entities such as the ESA  and JAXA are supposed to build and pay for it, so you don’t have to hold your breath for Congress to fund it. The ESA has developed significant closed-loop life support via its MeLISSA program (covered earlier by Sustainspace), so they certainly have advanced capabilities in closed-loop life support.

Artist’s concept of the Gateway power and propulsion and HALO in orbit around the Moon. Credit: NASA

Up-to-date details on iHab are scarce. High level requirements for deep space habitats have been determined by past studies, but it is unclear which of those iHAB will contain. Based on relatively easy-to-deploy capabilities that have already been developed, is expected that, at minimum, iHAB will provide capabilities for water recycling, modest food production (including plants), partial CO2 recycling and exercise.

The construction and deployment of the HALO and iHAB modules will be a significant expansion of the anthroposphere into space, and the most durable expansion into deep space. How long the Gateway will endure and be crewed are still open questions, but it is still a concrete step towards grander visions of humanity in deep space.

Further Information

Impact of Deep Space Missions on Life Support Development

Orion capsule approaching Gateway

NASA Lunar Gateway

The reconfiguration of the Deep Space Gateway into the Lunar Gateway and the accelerated schedule to land humans on the Moon will have significant impact on the development of regenerative life support systems and the sustainability of deep space communities of humans.

The existing International Space Station (ISS) is in low Earth orbit. That orbit provides a microgravity environment, intermediate radiation and some logistic challenges. It also involves a strictly-controlled habitat and severe limitations on plant care due to the severely impacted schedule of astronauts. In contrast, the deep space environment differs from that in low Earth orbit in several ways. First, there is considerably more radiation. Second, low Earth is much better protected by the Earth’s magnetic field. Third, it is more difficult and much more expensive to re-supply deep space.

There has been much evolution of planned deep space human missions by NASA, and hence its partners. At one point, there was a plan to have astronauts visit and retrieve an asteroid. Then the plan was to have a large Deep Space Gateway station that would gain experience for deep space missions and advance life support technology. Then the plan was to place humans on the Moon in a sustainable manner. Now the plan is for a minimal Lunar Gateway and a human landing to the Moon by 2024 and worry about sustainability after that milestone.

A common denominator among the plans has been the need to use the NASA Space Launch System (SLS) rocket and the Orion crew capsule. The SLS is an extremely powerful vehicle in terms of both propulsion and political clout. It will return some of the capabilities to NASA that were lost with the discontinuation of the Saturn V system. Since NASA has been strongly encouraged by the President to land humans on the Moon by 2024, private vehicles are now under consideration as well, if they can help achieve the deadline.

The original configuration of the Deep Space Gateway included a life support module that would have allowed the gateway to support astronauts with fewer resupply missions. It probably would have included a plant growth component.

However, due to the acceleration of a manned lunar landing mission, the Deep Space Gateway reconfigured minimalist approach focuses on providing an assembly node for short manned missions to the Lunar surface. There would also be a propulsion module and possibly an airlock module. A lunar lander would be ferried to the Gateway and the an Orion capsule would take astronauts to the Gateway. The astronauts would take the lander to the Moon for a few weeks, return to the Gateway and return to the Earth via the capsule. However, there will not be an enhanced life support module (at least not until much later).

According to a NASA source, after humans return to the Moon, then the Gateway and lunar base could focus on keeping people there on a sustainable basis. So plants in a long duration life support module might have to wait until after 2024.

The bottom line is that funding for deep space life support and sustainability will be likely delayed. If there are other cost overruns, life support and the biological sciences can get cut disproportionately. Since sustainability is untimely a cost-saver, this means that deep space communities will be more expensive for the foreseeable future, due to greater resupply expenses. The only silver lining is that there will be more time to “get it right” for sustainable life support technologies.