Advancing Sustainability in Space and On Earth
Developing a lunar refueling station to help sustainable space exploration fly further.
Recognizing the potential for commercial space companies to assist in achieving its strategic goals, NASA has embraced a public partnership with two companies – SKYRE, Inc. and Eta Space – to deliver technologies and capabilities needed for future space missions. Together they are developing an autonomous, commercial Lunar Propellant Production Plant (LP3) that will enable lunar refueling. Future space travelers will utilize the liquid hydrogen (LH2) and oxygen (LOX) produced by the SKYRE-Eta Space hardware on the moon to return back home to Earth and to travel to Mars and beyond. With imperatives of sustainability and efficiency, it will also pave the way for the infrastructure needed here on Earth for emerging hydrogen economies.
Sustainability is partially enabled by using local resources as much as possible. Current plans for In-Situ Resource Utilization (ISRU) on the Moon focuses on ice presumed to be in the permanently-shadowed craters of the Polar regions. Accessing and processing that ice will create a local supply of many of the consumables required for further exploration, as opposed to being delivered from Earth. Water and its oxygen and hydrogen elements can be used for a wide variety of space applications, including drinking and cooling water, breathing oxygen, reactants and LOX/LH2 for use as a rocket propellant. A LOX/LH2 refueling station on the moon will enable refueling for take-off and landing – a necessary capability for reusability.
The solution will integrate SKYRE’s water electrolysis and electrochemical hydrogen compressor with the Eta Space cryogenic liquefaction plant to produce propellant-grade oxygen and hydrogen to permit vehicle launches from the lunar surface. Says Steven Spratford, Chemical Engineer, “Essentially what we are doing is taking water, electrolyzing it to split the oxygen from the hydrogen, then using our EHC (electrochemical hydrogen compression) technology to compress the hydrogen. This enables liquefaction and storage (by our friends at Eta Space) in the energy dense cryogenic liquid phase, for use as a rocket propellant or to support our lunar base. However, due to the cryogenic nature of hydrogen, a portion must continuously boil off during storage”, says Steven. “Our EHC will recapture the boil off and compress it – creating a continuous loop whereby you don’t lose any vented hydrogen. You really can’t afford to lose any resources in space. And if we wish to be a space-faring civilization, we’ll need to figure out how to utilize and recycle every molecule. This project represents one small step toward making that a reality.”
Steven and the team have been working on getting a new design built, and then completing functional and performance tests. “This application required us to make some design modifications, like using a larger cell stack. And for the first time, we incorporated liquid cooling plates on the EHC.” says Steven. “We just ran an EHC stack on the test stand and it performed steadily and that’s a huge success. In particular, we were able to get up to our target current density – essentially the gas pumping rate – while keeping the voltage relatively low, when the stack was running at the intended operating pressure of 1500 psi. This means it’s energy efficient. You don’t generate as much waste heat and you can run more hydrogen with less total energy. These are two big milestones representing progress towards high through-put, high pressure hydrogen compression.”
The technologies being used for the LP3 also have relevant applications on Earth. “Our energy issues are pretty obvious. Given the complexities, I think it’s going to take a lot of different technologies working together to solve them by providing ways to capture, store and release energy in a truly clean and renewable fashion. I believe SKYRE’s technology is a significant part of that solution,” says Steven. “If you think about applying it on a localized scale on Earth, the combination of capture using renewable energy sources, electrolysis, storage via hydrogen compression, then release with a fuel cell, presents so much opportunity when it becomes economically viable. The beauty of it is that you can have a system built for one house or maybe a village in the middle of nowhere, and all you need is water and sun. You’re using local resources just like we are using them on the moon.”
SKYRE’s work is going to help sustainable space exploration fly further soon. And it is getting us that much closer to making renewable energy a reality here on Earth.
