New Materials Should Make Spaces Suits Lighter and More Versatile
We have about 11 years to gear up for the next moon mission if all goes as planned. That’s a bit more time than President Kennedy gave us in May 1961 when in the face of the Soviet Union’s advances in space, he challenged the country to put a man on the moon by decade’s end. Compared to 1961, we certainly have a head start on a lot of the technology needed to get there and back.
One thing I’ll be interested to watch develop is the space suit, the Extravehicular Mobility Unit, or EMU as NASA calls it. I imagine it will be completely re-engineered and redesigned for moon walks, or what NASA calls Extravehicular Activity (EVA). It’s likely that the new space suits will employ existing materials in new ways or new materials that we are just beginning to explore.
How New Space Suits Will Work
The new suits will probably be more like the ones last used in the early 1970s in the Apollo program than the ones we now see deployed for space walks outside the Space Shuttle around the International Space Station. For starters, the Apollo suit, including the life support backpack, weighed about 180 pounds. The Shuttle suit, including life support systems, weighs about 310 pounds. The moon’s gravity, about one-sixth of Earth’s, requires a lighter suit than the one used in the zero gravity of space. And for Mars, weight will be an even bigger factor, as Mars’ gravity is roughly twice that of the moon’s, or one third of Earth’s.
We have made so many advances in materials since the last Apollo moon mission that the new suits should be even lighter and more durable, flexible, and protective than anything that came before. Even now, new materials are being investigated to replace the current fiberglass Hard Upper Torso (HUT) with an all fabric Soft Upper Torso (SUT). The bulky and mostly metal cooling systems of the current Shuttle EMU will probably be replaced with membrane technology that will enable the astronaut to vent excess heat. Excess heat is a major concern as current Extravehicular Activity (EVA) is typically a physically demanding 4-6 hour task.
Other areas of challenge to bring the current EMU to a lighter weight, more comfortable fitting suit is to eliminate the need for the lithium canister scrubbers, more than likely to be replaced with selective membrane technology to allow carbon dioxide to vent outside of the suit, while keeping a constant flow of oxygen inside the suit.
Two Projects Have Potential
A couple of space suit projects have potential to change our concepts of what a space suit should be. One is a prototype for Mars developed by faculty and students from several North Dakota colleges and universities (http://human.space.edu/) Another is the Bio-Suit System that MIT is working on (http://mvl.mit.edu/EVA/biosuit/). Both are being developed under NASA grants.
The North Dakota program delivered a modified space suit in the spring of 2006. I say modified, because the suit is still using joints and rings and a hard upper torso to connect arms and legs to the main portion of the suit, not all that different from the way the current suit is assembled. There may one or two materials of interest here, but the outline of the program does not divulge much.
The MIT project is more interesting. It employs a design that eliminates the need for a torso shell, giving the astronaut excellent mobility. Called a Bio Suit, it is another example of the importance of the membrane technology and the need to remove carbon dioxide and heat. MIT seems to be focusing on the concept of Mechanical Counter Pressure (MCP) that uses highly elastic materials for greater mobility in performing EVA tasks. The current suits have limited mobility, which increases mission duration and causes greater fatigue for the astronauts. This increase in range of motion and dexterity for the astronauts is vital for Mars exploration.
Materials under investigation are Polyacrylonitrile (PAN) and Polyvinyl alcohol gels as well as shape memory alloys. Other materials include copperbase alloys, titanium-nickel alloys, polyimides and high performance nylons.
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