How to test a lunar rescue stretcher?
Two weeks ago, a new device for the rescue of astronauts has been tested underwater. The ESA’s Lunar Evacuation System Assembly (LESA) is designed to be deployed by a single astronaut in lunar gravity to rescue an incapacitated crewmate.
Despite the geological characteristics of the Earth, there is a place where testing a lunar device in a condition like the one you will face on the lunar surface. The bottom of the ocean floor, with its rocky, sandy terrain and buoyant saltwater, has more in common with the lunar surface than you might imagine. This is why two members of NASA mission NEEMO 23 tested the ESA’s latest prototype to rescue astronauts on the Moon.
The “lunar ambulance” is a pyramid-like structure, that enables an astronaut to lift their crewmate onto a mobile stretcher in less than 10 minutes, before carrying them to the safety of a nearby pressurised lander.
Under the sea…carrying out the test!
During NASA mission NEEMO 22 in 2017, Pedro Duque, ESA astronaut, and the NASA astronaut Kjell Lindgren tested an earlier prototype. They lived and worked onboard undersea habitat Aquarius for nine days, put LESA to the test.
Hervé Stevenin, ESA head of spacewalk training and Neutral Buoyancy Facility (NBF) operations says that LESA is the world’s first prototype for a system that will allow the safe and rapid recovery of a fallen astronaut on the Moon’s surface by a single spacesuit-wearing rescuer. The catalyst for its development came from a three-year Moondive study.
Commissioned by ESA and led by French company Comex, this study looked at how the 10-m deep pool at ESA’s astronaut centre in Cologne, Germany, could be used to simulate lunar gravity underwater to test equipment, tools and operational concepts for the Moon.
A key part of this work was identifying essential activities astronauts would need to perform while carrying out Extravehicular Activities (EVA) on the Moon’s surface. Rescuing a fallen crewmate emerged high on the list.
Stevenin declares how important is the skill of astronauts in recognizing a mate in difficulty and have the capability to rescue an incapacitated crewmember during lunar exploration.
Why this device?
Hervé explains that they began working on a lunar stretcher times ago. They face the importance of
providing rescue to an incapacitated crewmember during lunar explorations. A good understanding of the suit aspect and EVA itself was vital in the development of LESA, as EVA spacesuits are bulky and restrictive. EVA suits are also quite heavy, despite the reduced gravity of the Moon being one-sixth of that on Earth, and pressurised EVA gloves reduce an astronaut’s dexterity.
It is impossible that astronauts could carry a fallen crewmate over their shoulder while wearing an EVA suit. The heaviness of this uniform impedes any kind of extra movement. The objective of ESA was to bring all the rescue actions into the working range of the EVA-suited astronaut to ensure a rapid and safe rescue.
LESA can be transported like a golf caddy and placed close to the fallen astronaut to provide a lifting mechanism and a stretcher that is easy to manoeuvre, as what Herve reports. Once the rescuer has used the device to lift their crewmate and attach the stretcher to their back, they add wheels to the stretcher and transport them to safety.
Next steps for lunar rescue
There has been another evaluation of the second version of LESA during an underwater spacewalk in the Atlantic Ocean. The members of the current nine-day NEEMO 23 mission, ESA astronaut Samantha Cristoforetti and NASA astronaut Jessica Watkins carried it on a pair of weeks ago. The pair wore EVA gloves and take EVA suit constraints into account as they test the lifesaving device.
The pair tested LESA on Comex’s EVA spacesuit simulator. So, rather than taking turns to play the role of a fallen crewmember, the underwater weight of this suit simulator is equivalent to the weight of an astronaut wearing an EVA suit on the Moon.
Their feedback will be useful for further developments of LESA, also as ESA is trying to collaborate with NASA to improve the quality of space missions.