NASA’s First Lunar Space Station Modules Are Almost Complete
Apart of NASA’s big plan to return to the Moon, for the first time, the agency is building a space station in lunar orbit. These modules are intended to act as a home-away-from-home for astronauts during extended stays in lunar orbit. They also are meant to enable additional capabilities in support of the Artemis Program and the return to the Moon.
When the station is complete, it will feature many different segments and establish an impressive footprint, however, this being said, it will start as just two modules. These two initial modules are set to launch in 2025 which coming up fast. In order to prepare for that launch, the segments need to be completed well before the deadline to allow for extensive testing and qualification.
Right now we are seeing physical progress as they approach different milestones. At the same time, certain delays are causing concern for the future of this project and its timeline. Here I will go more in-depth into the physical station progress, the first two modules, possible delays, and more.
Physical Progress
The two modules set to launch first are named the Habitation and Logistics Outpost (HALO), and the Power and Propulsion Element (PPE). Together these two segments will provide power, propulsion, living quarters, and life support for astronauts at the Moon. Back in 2021, NASA awarded SpaceX a $331 million contract to launch both of these modules together on a Falcon Heavy. The mission was originally set to happen in 2024 but has since been pushed back to 2025.
As far as the modules, the agency describes the Power and Propulsion Element as “A foundational component of the lunar outpost and the most powerful solar electric spacecraft ever flown”. In other words, PPE will help maintain Gateway’s orbit around the Moon, along with providing additional power for the station. In terms of progress, a few weeks ago in late September, NASA tweeted saying, “Fabrication and assembly of Gateway’s Power and Propulsion Element (PPE) are well underway at@Maxar Palo Alto. The team recently completed assembly of the PPE’s central cylinder and will place it through a series of tests to ensure the hardware’s integrity for future flight.”
In addition, earlier this year, engineers from NASA and Aerojet Rocketdyne began qualification testing on the cutting-edge solar electric propulsion (SEP) thrusters. Specifically, the Advanced Electric Propulsion System (AEPS), built by Aerojet Rocketdyne, provides 12 kilowatts of propulsive power – over two times more powerful than current state-of-the-art in-space electric propulsion systems. The AEPS must undergo qualification testing before being certified to fly on Gateway. This exact system is core to the PPE module and its ability to keep Gateway in the proper position and orbit around the Moon.
The other module HALO, is where astronauts will sleep and spend the majority of their time during the initial Artemis missions. Unfortunately, this module hasn’t progressed as smoothly as the Power and Propulsion Element. It’s important to point out that both of these segments were contracted out by NASA to different companies. PPE is being developed and manufactured by Maxar Technologies while Northrop Grumman is responsible for HALO. When NASA picked Northrop Grumman, one of the most appealing decision choices was the fact that the company was basing the HALO module on the Cygnus spacecraft. A vehicle that was already actively being produced years ago in 2019 by the same company.
This gave the agency confidence that the segment design was realistic and could meet the overall project timeline. HALO is designed as the pressurized living quarters that will provide docking ports for visiting spacecraft like NASA’s Orion spacecraft, lunar landers, and logistics resupply craft, and serve as the backbone for command and control and power distribution across Gateway. The module is also meant to perform other core functions, including hosting science investigations, and communicating with lunar surface expeditions. Obviously, a very important module that needs to launch with the PPE in order to create a livable station.
Not long after winning the contract, Northrop Grumman successfully completed its initial preliminary design review for HALO. However, since then there have been a few roadblocks. For example, earlier this year the company took a $36 million charge on its contract, citing changing mission requirements and broader economic issues. In an earnings call, Kathy Warden, chief executive of Northrop Grumman, said “As it’s turning out on the HALO program, the requirements are not as stable as we or the government anticipated, and we’re working with them to address that change management as we go forward.” Despite these hiccups, they are continuing to make progress on the module and intend to have it ready by the 2025 deadline.
An Extensive Station
Even though Gateway will start with two relatively small modules, it’s expected to grow significantly over the next few years. After all, this station isn’t just NASA, but will also utilize help from the CSA, ESA, and JAXA. Looking at station blueprints, modules like the International Habitat, Logistics module, Refueling module, and Orion, are all expected to come together over time. We will likely even see a massive lunar Starship upper stage attached to the station at one point.
Focusing more on these extra modules, Gateway’s second habitation element, I-Hab is a pressurized module that will provide living quarters for astronauts visiting the Gateway, and multiple docking ports for visiting vehicles and other modules. I-Hab is led by ESA, which selected Thales Alenia Space – Italy as prime contractor. JAXA is also making significant contributions to I-Hab, providing the Environmental Control Support System, thermal cooling pumps, and batteries.
Provided by ESA, the ESPRIT Refueling Module is a habitable element that will transport cargo to Gateway, provide storage space once docked at the space station, provide fuel to Gateway’s propulsion system, and provide a view of space and the Moon through its windows. “ESPRIT” stands for European System Providing Refueling, Infrastructure and Telecommunications.
The Crew and Science Airlock will be a critical piece of infrastructure for Gateway’s planned minimum 15-year lifespan in lunar orbit, permitting crew and science payload transfers to and from the habitable environment of Gateway’s crew modules to the vacuum of space – transfers that will be essential for space station maintenance and conducting science in the deep space lunar environment. The Gateway Program is in active discussions with a potential provider for the Crew and Science Airlock.
While all these modules are great, as astronauts conduct missions at Gateway and prepare for lunar surface expeditions, they will need deliveries of critical pressurized and unpressurized cargo, science experiments, and supplies like sample collection materials. In March 2020, NASA announced SpaceX as the first U.S. commercial provider under the Gateway Logistics Services contract to deliver cargo and other supplies to Gateway. One logistics services delivery is anticipated for each crewed Artemis mission to Gateway. Combine this with the occasional lunar lander attaching to the station and you have what’s expected to be a full and lively station in lunar orbit.
After launching in 2025, the combined PPE-HALO will spend one year transiting to near-rectilinear halo orbit (NRHO) around the Moon, for an expected arrival in 2026. From here, on-orbit assembly of the fully realized Gateway space station will commence with the Artemis IV mission that will launch no earlier than September 2028. Artemis astronauts will enter Gateway for the first time on the Artemis IV mission. The primary objectives of the mission are to integrate I-Hab with Gateway and complete the second crewed lunar surface expedition of the Artemis missions. Over the next few Artemis missions, they will integrate more modules at the same time as they complete surface expeditions.
In order for the station to effectively support and help astronauts land on the Moon, a lot of work went into picking the exact orbit the station would utilize. Usually, there are two main options, a low lunar orbit or a distant retrograde orbit. A low lunar orbit is great for landing on the surface thanks to its close proximity, however, because of the Moon’s gravity, more propellant is required to maintain the orbit. On the other hand, a distant retrograde orbit provides a large, circular, and stable (or more fuel-efficient) orbit that circles the Moon every two weeks. However, what Gateway would gain in a stable orbit, it would lose in easy access to the Moon: the distant orbit would make it harder to get to the lunar surface.
Then there is NRHO, which is just right for Gateway, marrying the upsides of low lunar orbit (surface access) with the benefits of distant retrograde orbit (fuel efficiency). Hanging almost like a necklace from the Moon, NRHO is a one-week orbit that is balanced between the Earth’s and Moon’s gravity. This orbit will periodically bring Gateway close enough to the lunar surface to provide simple access to the Moon’s South Pole where astronauts will test capabilities for living on other planetary bodies, including Mars. NRHO can also provide astronauts and their spacecraft with access to other landing sites around the Moon in addition to the South Pole. Something we can expect to see more about in the next few years.
Conclusion
NASA is trying to stay on schedule and develop a one-of-a-kind space station in lunar orbit. The two initial modules, HALO and PPE are being manufactured as I speak with the goal of launching together on a Falcon Heavy in 2025. We will have to wait and see how it progresses and the impact it has on the space industry.