Talk:Suit design concerns
1/23/09 Assuming there is a Portable Life-Support System (PLSS) with the suit, this suggests to me that, within limits, much of the loading for the suit can be off-loaded by making it modular in design.
In the minimum mass mode there is no 'backpack' at all. Instead, the PLSS is mounted on a carrier and connected to the suit by extended umbilicals.
I imagine one type of "extra-mobile PLSS" as an ATV-looking thing for fast far-ranging EVA's. They are simply awesome in their handling of rough terrain. Navigaiter
This enables a very large, very heavy PLSS which could easily support twelve-hour EVA, if that were operationally desireable. The umbilicals would be long enough to allow very high freedom of movement within a radius defined by the safest maximum reach of the umbilicals. A ten-meter radius could be realistically baselined. Ideally, with locking bypass valves installed on the umbilicals, it could be thought of as a modular system with essentially unlimited potential reach. In reality, there is a practiocal limit to how far cooling fluids (water/glycol?) could be pumped for a given pump size. Such a system can provide a very robust thermal rejection, power, communications and tool support capability and would be a huge benefit for construction and spacecraft maintenace EVA.
?? Can't see a pracical long umbilical. Incident sunlight, with no atmosphere to moderate it and the temperature of the regolith in dayligh, will FRY everything without inches of insulation. So the thermal load on an umbilical is a power-soaker. But an ATV can get close to any Lunar Feature so why the long cord anyway? Navigaiter
Loading the suit aids traction, but not exertion loads. the astronauts found that they were able to cover a great deal of distance over the lunar surface carrying the equivalent of about 20 kilograms deadweight. The problem was the suit's stiffness fought them and their center of gravity was an issue, particularly during intricate maneuvers such as bending lower to pick up items. Even with the low-g, they were experiencing metabolic loads nearly equal to doing the same tasks in terrestrial simulations without the suit loads. Going uphill, in particular, often resulted in alarming metabolic jumps. All of this would seem to suggest off-loading the suit's mass from the astronauts themselves and allowing them to trade off traction for a more even metabolic load. This is particularly the case if you assume most of the astronuts EVA will be on tasks relatively short range from the base site.
I'm imagining distinctive MoonWear, pants legs with a bulge ahead and behind the calf containing suit systems down low to keep the CG low. Navigaiter