On March 11, I went to Glenn Research Center in Cleveland, Ohio, to take part in NASA’s “Moon to Mars” announcement event.
A little about the Glenn Research Center
Cleveland isn’t the first place one might expect to find a world-class NASA research center. But, Glenn (and the nearby Plum Brook Station, considered part of the center) are home to many world firsts, biggests, and bests, including:
- The Space Power Facility, which at 122 ft (37 m) tall and 100 ft (30 m) in diameter is the world’s largest thermal vacuum chamber (it began its structural life as a nuclear containment dome!)
- Zero Gravity Research Facility: an 432-ft (132 m) tall vacuum chamber (in a ~500-ft underground shaft), which provides up to 5.18 seconds of microgravity for experiments, by dropping them from the top. It’s the largest of its kind in the world.
- Loads of wind tunnels for all sorts of experiments, from the 9×15 Low-Speed Wind Tunnel (the most utilized low-speed propulsion acoustic facility in the world), to the Hypersonic Tunnel Facility, which involves such high energies that it must be remotely operated for safety.
- In the Stirling Research Lab, the longest running heat engine, at 110,000 hours and counting (actually more than that, since that number is from July 2018 — over 13 years).
Glenn continues to provide these facilities and many others to researchers and corporations. Most space vehicles make a test trip through Glenn’s facilities; for example, SpaceX’s recently demonstrated Crew Dragon capsule went through a few tests there. On my trip, however, I toured some of the facilities that are specifically relevant to NASA’s “Moon to Mars” initiative.
First, we visited the Simulated Lunar Operations (SLOPE) Laboratory, where NASA scientists test rover tires and other equipment related to locomotion and operation on the lunar surface. This facility is critical to proving technologies such as shape memory alloy-based tires (based on materials like Nitinol), which promise stronger, more resilient solutions to rolling around on the moon and Mars.
How often do you get to see tire racks full of space wheels?
Electric Propulsion Laboratory (EPL)
Here, electric propulsion (like gridded ion thrusters and Hall thrusters) are researched and tested in vacuum chambers (from tiny to huge) that simulate the conditions of space. This capability is key to developing NASA’s Gateway in lunar orbit, which they plan to propel and maneuver using the most powerful Hall thrusters ever developed.
Stirling Research Laboratory (SRL)
Last, we went to the Stirling Research Lab to see their work in thermal energy conversion, or converting heat to electricity.
One method under heavy research is the use of Stirling engines. They have the longest running heat engine in this lab, at over 110,000 hours. That’s with no maintenance or replacement of parts! So it’s clear that heat engines with moving parts can withstand long periods of use — and that’s critical in space applications, since trips to and from target bodies can take months or years.
Another important part of the Stirling Lab’s mission is research and development of nuclear power for space. One of the more promising developments is being called Kilopower: essentially, it is portable nuclear fission power. It transmits heat from a controlled uranium core via sodium-filled heat pipes to several Stirling heat engines, which generate electricity. It can operate in a gravity field with the simple heat pipes, or can theoretically be fitted with “wicking” heat pipes that can operate in microgravity.
- NASA are moving their innovation and operations out of low earth orbit (now that it’s well on its way to being commercialized) to the moon and nearby space. They want to apply their research and development to technologies that can be used on a trip to Mars, but prove them closer to home.
- Glenn Research Center will play a role in many key technologies to accomplish the mission, including electric propulsion, energy solutions, and surface operations like in-situ resource utilization (ISRU).
Proving technologies closer to home that we will need for an eventual human mission to Mars sounds like a good idea to me. The SpaceX plans really only provide transportation — so somebody has to do the research. And, I’m glad to hear that NASA is setting its sights higher, and for once has some good funding (requested, at least)!
But, the Gateway concept is sort of confusing to me. They say it would be a reusable, permanent “command and service module” in lunar orbit, and missions to the moon could use it as a base. If the majority of the science and work will be on the lunar surface, why do we need the Gateway? Direct lunar missions take longer, sure — the trip from Earth is around three days, versus maybe a few minutes for a descent from lunar orbit. But, the launch window to return to Earth from the moon is always open: Earth is always in the same place in the sky. If the Gateway is orbiting the moon, doesn’t that mean the launch window to get to it from the moon’s surface will be instantaneous and relatively rare?