From Battlecruisers to Space Tug: Saving NASA’s Lunar Gateway
Could a pair of 1920’s U.S. Navy battlecruisers that were converted into aircraft carriers give NASA a path to save the Lunar Gateway space station from program cuts? We think so, and the Mars Blueprint proposes that there is an opportunity here for NASA to use the Lunar Gateway modules as the core of a deep space transport designed to accelerate a Mars bound spacecraft faster and safer than any current plan enables.
For a more detailed explanation on the space transport or “tug” concept check out the deep dive article: NASA Nuclear Space Tug: A Game Changer for Mars Missions.
So what could a pair of 100 year old U.S. Navy ships possibly have to do with NASA’s Lunar gateway space station that is currently under construction? They share a common fate as both programs faced/face potential cancellation due to policy changes after construction was well underway. And yet, the battlecruisers survived despite all the odds, were redesigned, and found new life as the famed aircraft carriers USS Lexington (CV-2) and USS Saratoga (CV-3) which played pivotal roles in the WWII Pacific theater.
The U.S. Navy aircraft carriers USS Saratoga (CV-3) and USS Lexington (CV-2) off Diamond Head on 2 February 1933. Credit U.S. Navy
A little historical background for context. After WWI the United States, the United Kingdom, Japan, France and Italy signed the “Washington Naval Treaty” in 1922 which set strict limits on the number and types of warships each country could produce. To comply with the treaty, two U.S. battlecruisers (Lexington and Saratoga), which were already well into construction, were converted into aircraft carriers. Their original hull and propulsion design supported the dimensions, speed and mobility required of a carrier with some compromises made to account for a smaller hull than a ground-up design would have used. This decision saved the taxpayers countless thousands of dollars and the U.S. Navy gained two lethal warships that 15 years later turned the tide of WWII in the Pacific.
You may be wondering why this has anything to do with the Lunar Gateway or Artemis as those programs have not – yet – been cut. Simply put, the political winds have changed, and the newly elected Trump administration is increasingly focused on Mars and critical of the Artemis moon mission architecture. To illustrate this, in both President Trump’s inauguration speech and his recent address to congress, he clearly stated that American astronauts are going to Mars. In his first two months in office, he also appointed Elon Musk, CEO of SpaceX, as a defacto advisor to the administration. This is critical because in a January post on X.com Musk referred to the Moon as “a distraction” and referred to the Artemis program as an extremely inefficient jobs maximizing program. Given the fact that Trump neglected to even mention the Moon and doubled down on Mars in both critical speeches it is highly likely that he shares Musk’s opinions on the Moon programs. This would place Artemis and the Lunar Gateway at risk of cancellation due to a policy change just like the battlecruisers Lexington and Saratoga a century earlier.
The solution the Mars Blueprint proposes is to repurpose the Lunar Gateway modules that are already in production into a first generation Mars “Space tug” designed to reduce the transit time of a commercially designed lander such as the SpaceX Starship. As we stated in our previous article the shorter the transit time, the less risk there is to the astronauts from radiation and zero-g effects, the less consumables are required, and the greater chance of mission success. This would be both a fiscal win for taxpayers in saving the modules that are already nearing completion but also a win in making any NASA Mars mission faster and safer.
Gateway to “Space Tug” Repurpose Pros and Cons:
Pros: Functionally the reason this plan makes sense is because the Lunar Gateway was designed from day one to study deep space which means the modules are designed with similar mission parameters as a spacecraft would need for a Mars mission. The Hall effect thruster propulsion system being built is a much larger version of the ones previously used on the Dawn and Psyche deep space missions and is well understood and very efficient. And like their naval predecessors, the main components of the Lunar Gateway are already past initial construction and into/nearing the testing and/or delivery phases. This means they should be complete and in space by the time SpaceX has an astronaut rated Starship flying.
Cons: While the Lunar Gateway was designed to study deep space and has relatively powerful thrusters compared to anything previously launched, it was not specifically designed to fly to Mars and will need design modifications for a long duration mission. Also, a July 2024 GAO report identified potential issues with the Gateway’s propulsion system maintaining control of the integrated Starship-Gateway stack to maintain Lunar orbit. Gateway program officials are already on record in the GAO report that a potential solution is to integrate starship and gateway into one control system which would allow it to handle attitude control by simultaneously using both craft’s systems. These issues, and others to come, are no more insurmountable than turning a battlecruiser into a carrier by looking at what the existing design already offers and adapting it to work for a new purpose.
The modules under construction include:
The HALO (Habitation and Logistics Outpost) module: Nearing completion/delivery.
Gateway’s HALO (Habitation and Logistics Outpost) in a cleanroom at Thales Alenia Space in Turin, Italy. Credit: Thales Alenia Space
HALO has already completed pressure and static load testing by Northrop Grumman and the subcontractor Thales Alenia Space and is next scheduled for final outfitting and power testing.
The Power and Propulsion Element (PPE) module: In assembly phase.
The Propulsion Bus Module of Gateway’s Power and Propulsion Element undergoes assembly and installations at Maxar Space Systems in Palo Alto, California. Credit: Maxar Space Systems
The PPE has undergone static load testing and is being assembled right now by Maxar Space Systems. Once completed, the PPE will be the most powerful solar electric spacecraft ever flown. This system includes a solar power system capable of producing 60kW of electrical power of which 50kW can be dedicated to the onboard Hall effect thrusters.
Once the HALO and PPE modules are completed they are scheduled to be joined together and launched on a Falcon Heavy rocket.
All of these systems exist in some form today, are on track to be completed, and with modifications for the longer journey, can be launched as a complimentary system to a Starship mission to Mars. This adaptation alone will dramatically shorten the time to transit the approximate 140 million mile Earth to Mars journey in less than the 234 days one way average transit time (based on average of previous mission transit times). Also, building a “Space Tug” allows NASA to take advantage of the strengths and weaknesses of a space based system and the Starship system without sacrificing performance on either. A space based tug adds a constant thrust option for the Starship transit instead of the currently planned launch and coast design cutting the one way trip down from 230+ days to under 100. Also, the space tug is by design optimized for space and can provide consumables storage, power, propulsion, and additional life support on a platform that stays in orbit. This is critical as it keeps heavy solar panels and consumables for the return journey off of Starship – which needs to land on Mars – while both allowing more Mars equipment to be landed and also increasing the likelihood of a successful landing/re-launch.
If the Trump administration and NASA want to go a step further they can take our recommendation and upgrade the design to follow the proposal by Ad Astra and the Space Nuclear Power Corporation (SpaceNukes). These companies propose a craft that uses the SpaceNukes Gen1 nuclear reactor paired with Ad Astra’s Variable Specific Impulse Magnetoplasma Rocket (VASIMR). This upgrade would increase the propulsion system’s available thrust over the current design by at least 5x using the VASIMR thruster, eliminate the reliance on solar power by using the Kilopower nuclear power system and could lower the one way transit time to around 100 days.
An overview of a proposed spacecraft utilizing Nuclear Electric Propulsion. Credit: Ad Astra
Bottom line, if Artemis is going to be cancelled or heavily descoped, we encourage the Trump administration and NASA to take a page out of Naval history and send the Lunar Gateway to Mars instead of the scrap heap. Lexington and Saratoga turned the tide of the war in the Pacific, just think what the repurposed Lunar Gateway could accomplish for American ambitions on Mars!