In 2001, NASA engineer Michael Ewert developed and patented a unique solar-powered vapor-compression refrigeration system that operates without batteries or external power of any kind. The system, which is powered by a photovoltaic panel and custom-designed electronic controls, could be used not only for long-duration space missions but also to build more environmentally friendly refrigeration systems here on Earth. Currently, Ewert is the Deputy Project Manager for NASA’s Exploration Life Support Project, which is developing new technologies needed to sustain human life on long-duration space exploration missions.
NASA Tech Briefs: What is the Exploration Life Support Project, and what does NASA hope to accomplish with it?
Michael Ewert: Exploration Life Support – or ELS – is one of about two-dozen technology development projects that NASA has to develop the new technologies needed for future human exploration missions. For ELS in particular, our goal is to create the technology that will help keep the crews alive during long duration missions without relying so much on resupply from Earth. On space shuttle the missions are fairly short and on the International Space Station they have the ability to resupply fairly frequently, but for going to Mars or other long missions, that won’t be the case.
NTB: One of the Exploration Life Support Project’s stated objectives is to develop new technologies that are efficient with respect to resource requirements such as mass, power, heat reaction, volume, crew time, consumables, etc. Can you give us some examples of the types of projects the group is working on in these areas?
Ewert: One example is that the space shuttle uses lithium hydroxide canisters to extract carbon dioxide from the atmosphere after the crew breathes it out. We’re developing an amine swing-bed technology that can be regenerated by exposing the bed to the vacuum of space intermittently. That way we won’t have to throw away any lithium hydroxide canisters.
Space station also has some regenerable processors for both air and water, but they take quite a bit of power, so our Exploration Life Support Project is working on several options for both air and water to help reduce the power consumption for an enclosed life support system.
NTB: Two of the primary areas of research your group has been involved with are water recovery and waste management. These are obviously crucial to the future of long duration manned spaceflight, or the establishment of a lunar outpost. What kind of progress has been made to date in these areas?
Ewert: We have extensively tested three wastewater distillation technologies recently and are in the process of determining which performed the best for the kinds of wastewater streams we expect to see in future missions. Part of the research is figuring out how the process will handle the wastewater streams with things like toothpaste or shaving cream that does not go into the wastewater system currently. We learned that the toothpaste being used was just not being tolerated well, so we had to research and find another toothpaste to use that can be processed in the processor.
Beyond that we’re developing or evaluating several technologies for water recovery from the brine that is left over after the distillation process. Even after the primary processor distills the water, there’s still a concentrated salt solution that has a fair amount of water left in it, so we’re trying to recover that last little bit of water from the brine.
For solid waste we’ve evaluated a variety of technologies working with our colleagues at Ames Research Center and with several SBIR companies. One exciting one is a plastic melt compactor, which heats and compresses mixed trash, melts the plastic in the trash, and extracts the water at the same time, so you’re left with a stable plastic disk, kind of like a hockey puck, and the volume of the original trash is reduced by about a factor of ten. It also helps deal with the smell that could be created by microbes in the trash.