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.