Last week a smergency (sim emergency) hit the HI-SEAS habitat: a radiation event! After receiving word from mission support that our remote satellite picked up additional solar proton levels, the crew needed to act fast to evacuate our habitat and seek shelter in a lava tube. High radiation exposure can ruin electronic equipment and injure or kill humans – it’s a high risk factor for space exploration. Our habitat is above ground and lacks permanent radiation protection, so additional shelter is required when radiation levels increase. Crew V designed an evacuation procedure in advance of our event that included gathering supplies, getting suited up and establishing a route to our shelter location. Radiation events can last hours, so the crew needed to be well prepared for a long wait.
Several weeks ago, the crew documented a possible safe haven in one of the lava tubes near the habitat. Lava tubes are long cave systems created when flowing lava cools faster on the outer surfaces than in the middle. The cooled lava solidifies forming the walls and ceiling of the tube, while the molten middle continues to flow clearing a path inside. Over time, the ceiling of some lava tubes will collapse, creating an opening into the tube system called a skylight. For our emergency shelter, we needed a skylight that we could easily climb into and a sufficiently large connected lava tube that would house us during our emergency. We spent several EVAs searching out a suitable location.
Josh and I created a walking route over the lava field to our shelter tube that would be easy to follow. It needed to be a simple path because a radiation event could happen at any time, and traversing out in the lava at night is a tough challenge. Flows that appear easy to navigate during the light of day can become confusing and disorienting at night. I know this first hand because we practiced our emergency evacuation one evening in advance of the actual radiation event. As the designated navigator for our evacuation plan, I needed to lead the team to the skylight and back to the habitat safely. During the day, color and texture differences give you a clue as to what patches of lava will be the easiest to hike over. But at night, all color is muted and the shadows from the flashlights can falsely emphasize texture. We learned from our rehearsal drill which parts of the path were not working and we fixed them to prevent further confusion.
The actual radiation smergency was pretty calm. The crew knew how to take action and we were out the door with one minute to spare on our goal time. I quickly navigated our route and the crew was in our lave tube faster than our practice time. Sheltering largely consists of talking with your crew mates, playing cards, eating snacks and taking a nap. We spent many hours in the lava tube shelter and while it’s not the most stimulating way to spend a day, it was a nice little escape from our regular schedule. The crew returned at the end of the day feeling a little sore from sitting on the hard rock floor, but safe and well.