NEEMO: An Analog for Asteroids
As you may know, NASA has been working on new concepts for the human exploration of asteroids. Across the agency, experts are being called into action to develop solutions to this new challenge. In particular, NEEMO-15, slated for October 17th-26th, will test new tools, techniques, timelining approaches and communication technologies which could be useful when humans approach asteroids in space. (Go here to learn more about the NASA Extreme Environment Mission Operation, or NEEMO.)
The concept of visiting an asteroid challenges our experience like never before. Gravity on an asteroid is negligible, so walking around on one isn’t really an option. So anchoring to the surface will probably be needed. But what to anchor to? They’re all made up of different materials, some solid metal - others piles of rubble, and many are a combination of rock, pebbles and dust. To the NEEMO-15 team, weak gravity and diverse materials present problems whose solutions can be experimented with on the ocean floor. And what better place to do that, than the extreme conditions of a multi-day underwater mission at Aquarius Reef Base in Key Largo.
The NEEMO-15 mission will be in October, and in an engineer’s mind, that means there’s still time to iterate on designs. Today the engineering team took some of those designs into the field. One of the devices tested today was a “spacesuit waist ring simulator”. It acts as the waist structure of a spacesuit would, except it’s attached to a diver wearing SCUBA tanks. It holds EVA tools, provides stability against structure, and even blocks some of the view, just as a spacesuit’s waist ring would. So today, after constructing this device in labs and workshops, it was finally time to put it in the water. After estimating it’s weight and buoyancy (and yes, there were bets on whether it would float!), it finally had its first taste of the ocean while still dockside. It checked out, as did the other tools and giant fiberglass “rockwall” that some of the experiments would mount to. So after the paperwork was all signed off, the team set out to the reef.
[caption id=”attachment_3335” align=”alignright” width=”300” caption=”Engineers Prepare the Rock Wall, a surface to provide attach points on the ocean floor, for it’s trip into the depths.”][/caption]
When arriving at the site - on the same reef but some distance away from Aquarius - the team lowered the rockwall to the ocean floor. Then, one-by-one, test subjects, utility divers, and support divers worked through their checklists and started the clocks on their dive. Astronaut Mike Gernhardt, the test subject actually in the “rig”, found the buoyancy to be near perfect (something that can sometimes take 30 minutes to correct), and started the experiments right away. The first thing that struck everyone was the visibility - the bright sunny, calm day helped the lighting - but the silt being kicked up made it impossible to see further than 10 feet. For the most part this didn’t affect the experiments, and the team pressed ahead. They tested hand-over-hand translation with anchor points on the rockwall, foot-restraint ingresses, anchoring in the silt to stabilize the setup, and using a rigid standoff attached to the waist ring for body stabilization. All while their time was ticking away - and they were not able to speak to each other. This was shaping up to be quite the debrief session.
[caption id=”attachment_3336” align=”alignleft” width=”250” caption=”A test subject evaluates the spacesuit waist ring simulator, and uses a mask that allows for multiple subjects to talk to each other (although comm. was not used today).”]1[/caption]
Once back on the boat, the crew discussed what they had learned. Either luck or excellent prediction had caused the rig to be perfectly buoyant, but some stabilization was needed on the waist ring - and the fins - they proved to be positively buoyant by sending the subject’s feet sinking after they were removed. Mike was proud to share an interesting discovery: while holding an excursion line anchored in two locations on the “asteroid”, one could effectively pull against the surface and walk, just as if there was gravity! There were other lessons learned, and many adjustments that would need to be made overnight and in the next few days, so the team used the trip back to base to rest and, well, talk more about the big picture.
I guess you could call it an engineering brainstorming session. Not one with whiteboards, flowcharts and venn diagrams, but just a bunch of people, passionate about space exploration, talking on a boat. They all had huge variations in their backgrounds and individual training, and just witnessed a sampling of how difficult it will be to someday explore an asteroid. Were the issues they saw today the same ones we’ll face on an asteroid? No, but some of them were strikingly analogous: The near-zero visibility had a similar effect to what could happen after touching the surface of a dusty asteroid. Body movements made on the ocean floor while “almost” neutrally buoyant are similar to what astronauts will face when moving across the surface of an uncharted asteroid. And how will we know what anchoring techniques will be effective? As the team neared the base on the shores of Key Largo, their conversation shifted to the varieties of anchoring tools we use here on Earth. Not knowing what kind of surfaces are out there is making us consider a variety of approaches from many “analogous” situations here on Earth: rock climbing, foundation repair, even drift diving.
[caption id=”attachment_3331” align=”alignright” width=”250” caption=”The engineering team used what was learned during the day, to retool hardware needed for the next day’s runs.”]2[/caption]
This was just a snapshot of one day of experiments in preparation for the NEEMO-15. The countless hours that go into getting ready for a mission are one of the many similarities to NASA’s space missions. Significant is the fact that NEEMO-15 will mimic something that has never been done by humans before. The question could be posed: Isn’t visiting an asteroid just a combination of what we have done in the past? Combine the weightlessness, tethering and translation techniques on the International Space Station, and then add to that all of the knowledge gained putting human feet on another world during the Apollo program. Right?
Not quite. The final discussions of the evening (after hours of replanning, retooling and regrouping) were about how asteroid exploration is definitely the most challenging of both worlds. Exploring a possibly dusty, wholly unknown, completely uncertified, essentially weightless, “surface” of an asteroid, will definitely be more challenging then combining the sum of our lessons learned from the Moon and ISS. Those experiences under our belt will be the basis of much that NASA does in the future - but we all agree it’s a good thing we’re learning how to hone our skills, here on Earth.