The Mars Suit

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mental_avenger

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On another thread , which shall remain nameless, there was a discussion about the effects of losing/removing your spacesuit helmet on Mars. There was a great deal of disagreement about what would happen. One of the points centered around whether the type of spacesuit would have any effect on how long the person would survive. That led to the question of how a Mars Spacesuit would be constructed.<br /><br />The Mars Suit.<br />High Altitude/Space suit design has changed a great deal over the years, from the Wiley Post suit reminiscent of a hard hat diver, to the Dover M-suit, with a lot of variation in between. One thing noticeable about the variety, is that many different designs can and do work. Until now, suits had four main uses, high-altitude flight, long duration capsule missions, space station EVA, and Moon surface. Each of these environments favored a different design, and there were dozens of suits designed and built over the years.<br /><br />Now we are faced with another environment, different than any of the others. Again, many different designs are being tried, but several things remain constant. The Mars Suit will need to be lightweight, comfortable, flexible, and warm. It will also have to compensate for the lack of a substantial atmosphere on Mars.<br /><br />Most space suits have an inner pressure suit, and an outer heat/cold/abrasion suit. The Dave Clark G4C suit had a gas-tight, man-shaped pressure bladder made of Neoprene-coated nylon and covered by load-bearing link-net woven from Dacron and Teflon cords. The outer suit is needed for protection against the heat and cold of space. Modern space suits are operated at a reduced pressure. For instance, the Dover M-Suit uses a pressure of .26 atmospheres(4psi). The Dave Clark D-1 (S1035X) operates at 3.75psi. The NASA MKIII operate <div class="Discussion_UserSignature"> <p style="margin-top:0in;margin-left:0in;margin-right:0in" class="MsoNormal"><font face="Times New Roman" size="2" color="#ff0000"><strong>Our Solar System must be passing through a Non Sequitur area of space.</strong></font></p> </div>
 
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CalliArcale

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Interesting!<br /><br />The first thought that actually popped into my head is that maybe it should be a really bright greenish-yellow. That should show well in low-light situations *and* contrast well with the background terrain during the day. The suit shown above might blend in a bit too well. Then again, it's not like the astronauts are likely to go wandering away from each other, so maybe that doesn't matter too much. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>
 
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bobvanx

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Yeh.<br /><br />I'd guess the moon suits were white for practical rasons (less absorbing of solar infrared, perhaps) but the public and promoters went: "white=moon" and therefore "Mars=red."
 
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cookie_thief

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I think white would be a rational choice as it would be easier to locate contact points on the suit to check for tears etc. It would also make it easier to locate a wayward martianaut should he/she wander off. For identification purposes I think each explorer would do well to have a different colored helmet. Calli can have her greenish-yellow helmet, you can have a red one and so on.
 
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astrophoto

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wouldnt a silverish color reflective suit help reduce radiation and also provide a super shiny surface to help locate wandering 'nauts?
 
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mental_avenger

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The suit in the photo is orange for survival/recovery on Earth. The color of the suit is only incidental, I was referring to the general appearance. Although the A/P 22S-3 shown in the photo is a full pressure suit, it is similar in appearance to the S1035 APPA suit worn by Shuttle Astronauts, including John Glenn. The S1035 is a partial pressure suit, operateing at 3.75psi.<br /><br />On Mars, the color would probably be darker, to absorb heat, not reflect it. But again, that is a relatively minor issue on Mars. What is important is the construction of the suit, what it is made from and how the layers perform their specific jobs. I was rather hoping for a technical discussion, not a fashion critique.<br /><br />The suit below is the S1035 in white.<br /> <div class="Discussion_UserSignature"> <p style="margin-top:0in;margin-left:0in;margin-right:0in" class="MsoNormal"><font face="Times New Roman" size="2" color="#ff0000"><strong>Our Solar System must be passing through a Non Sequitur area of space.</strong></font></p> </div>
 
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rogers_buck

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My god, there are lawyers there already? Guess I better read the post. (-;
 
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CalliArcale

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<blockquote><font class="small">In reply to:</font><hr /><p>I was rather hoping for a technical discussion, not a fashion critique. <p><hr /></p></p></blockquote><br /><br />I didn't mean it as a fashion critique. I was just thinking about visibility of the suit. Obviously certain suits are orange for recovery on Earth for that very reason -- it stands out well. But it just occured to me that it probably wouldn't stand out as well on Mars. *shrugs* It's probably not that big a deal anyway. I seem to recall the Apollo EMUs would get very dirty, so they'd probably end up Mars-colored regardless of what color they started out.<br /><br />On a more practical note, how are they addressing the joint flexibility issue? I know it's a major problem with gloves. Astronauts have to have considerable hand strength, especially on spacewalks where you get around mostly by going hand-over-hand. They say it's like squeezing a tennis ball for eight hours solid. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>
 
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rogers_buck

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Humm. Seems like the 6 millibars ambient ought to be good for something - if nothing else for heat exchange.
 
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JonClarke

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A Mars mission will pose EVA challenges unprecedented in spaceflight. I suspect that these will require a radical new approach to suit design. It won't be enough to modify existing suits.<br /><br />1. Duration and number of EVAs<br /><br />Most recent Mars mission proposals have stays on Mars of ~540 days. Even the most conservative estimate would suggest weekly EVAs, perhaps even one every other day. A Mars mission would clock up more EVA hours than all other missions put together (unless there is an extensive lunar program beforehand). This has big implications for suit wearability and durability, design, and EVA management.<br /><br />2. Mars environment<br /><br />The Mars environment contains large amounts of very fine, saline, oxidising, magnetic and conductive dust. Beause human EVAs are much more vigorous than robotic operations large abouts of dust will be kicked up and deposited on the suits. It will play havoc on suit designs that reply heavily on bearings, e.g. hard suit. Electronics will need special shielding. Careful cleaning will be required after each EVA to minimise dust being brought into the hab for both health and maintainance requirements. Martian dust is finer than lunar dust, so will be much more pervasive. Orbital EVAs have no dust at all. <br /><br />The thermal regime will be different to the moon or orbit. because of lower radiant energy intensity, more diffuse lighting, an extremely cold ground, and the presence of an atmosphere. Cooling systems will be different. <br /><br />The 38% G environment on Mars is a real challenge. It does not matter is a earth orbit EVA suit masses quarter of a tonne. It will matter on Mars. Because the gravity on Mars is twice that of the moon, even an Apollo type suit will be too heavy.<br /><br />3. Management<br /><br />Current EVAs are rehersed many times on earth. They are carried out in an environment that is well understood, the externals of a space station. On Mars every EVA will be different, in a <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>
 
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mental_avenger

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<font color="yellow">On a more practical note, how are they addressing the joint flexibility issue? </font><br /><br />That is one of the reasons for partial pressure (3.75psi) suits. The lower pressure allows greater flexibility, i.e. no balloon effect. However, it also requires prebreathing oxygen for 3 hours. That is because, in order to have such a low suit pressure, they have to run pure oxygen to keep the oxygen partial pressure up. We know that this can be dangerous, so I think it will end up a compromise. .56 bar (8psi) only requires about 30 minutes prebreathing, while only sacrificing a little flexibility. I expect the habitats, and therefore the suits on Mars to be run at about .5bar.<br /> <div class="Discussion_UserSignature"> <p style="margin-top:0in;margin-left:0in;margin-right:0in" class="MsoNormal"><font face="Times New Roman" size="2" color="#ff0000"><strong>Our Solar System must be passing through a Non Sequitur area of space.</strong></font></p> </div>
 
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mental_avenger

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Jon,<br />Excellent post, excellent. You have covered almost everything. A few points of discussion, though.<br /><br />Gemini suits were worn for very long periods of time. They were sort of a compromise between 100% safety and wearability. IIRC, those astronauts never took off thier suits during the missio, which could last for two weeks. But of course, they didn't have to go EVA and fix things either.<br /><br />OK, like you say, it is probable that Mars missions will require daily excursions on the surface. That is one reason that Mars Suits will have to be flexible and tough. I expect the suits to be similar to the Mars Skin suits. This is what I was advocating in the original postings on the other thread with the form-fitting neoprene suits. It is also why I said that the severity of the results of losing your helmet would depend on the type of suit.<br /><br />On other discussion boards, we have discussed the Mars Suit issue, and arrived at essentially what the Mars Skin designers are using. It makes sense.<br /><br />The Martian “fines”, the term normally used for the very fine Martian dust, would indeed be a big problem for suits with movable joints. In fact, it is unlikely that any suit with mechanical joints will ever make it to Mars.<br /><br />You bring up an interesting point in cleaning the suits. The easiest way would be to have a two-stage airlock. The outer chamber would be vented to the outside. The Martian would walk into this chamber and activate an arrangement of C0<sub>2</sub> jets which would blow off the dust. Without an atmosphere, the dust would settle quickly to the floor. He would then proceed to the inner chamber, the ac <div class="Discussion_UserSignature"> <p style="margin-top:0in;margin-left:0in;margin-right:0in" class="MsoNormal"><font face="Times New Roman" size="2" color="#ff0000"><strong>Our Solar System must be passing through a Non Sequitur area of space.</strong></font></p> </div>
 
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rogers_buck

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Here's a different concept.<br /><br />Seems like Mars is going to smell far worse than the moon, so you probably won't want to get undressed indoors.<br /><br />Maybe a good model for a mars suit should be something more vehicle than suit. Something that stays outside and docks with the habitat. An astronaut crawls in/out of the suit/vehicle through a docking port. Sort of a cross between the Michelan man and Ripley's fork lift on Aliens is what I have in mind. Kind of like the deep diving hard suits used today on oil rigs, but with an assisted mobility exoskeleton using technology derrived from the military's exoskeleton research. <br /><br />Such a suit/vehicle might be large enough for long duration comfort and might be big enough to fit two in an emergency. In case of emergency two suits would dock with each other and the occupant of the damaged suit would transfer to the working suit. This would allow for the removal of redundant systems from the suits. Docked suits might also be interlinked for quadrapedal locomotion and stability, the first horse galoping on mars.<br /><br />The assisted mobility would allow for a heavy suit with a lot of consumables. Astronauts could also retrieve and carry back a lot of samples in containers on either side of the legs. Software and FO gyros could override the astronaut's own sense of balance to prevent tripping. A suit might even be programed to walk an unconsious astronaut back to base camp in an emergency.<br /><br />If not a power assisted exoskeleton, then maybe a Segway style two wheeled suit or even a four wheeled suit. An electric ATV with a pressure tent. You get the idea.<br /><br />For up close and personal type inspections the astronaut could done a lightweight body glove connect to the docking port via a few meters of tunnel material. Something along the lines of the medical issolation suits in Andromeda Strain, but made of light weight materials like Kevlar weave. The astronaut would only be fighting the air
 
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mental_avenger

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The deep sea “hard suit”, more formally known as the Atmospheric Diving Suit (pictured below) was developed for very deep diving (1200 feet) with some degree of mobility. Shallower dives rely on much simpler and less restrictive suits for a very good reason, mobility and dexterity. <br /><br />Anyone who has done much work outdoors knows how inconvenient it is to work in heavy clothing. In cold weather, with heavy parkas and thick gloves, some tasks become extremely difficult if not impossible. Therefore, the trend is always towards the lightest, most flexible attire available. On Mars, work will be difficult at best. “Wearing” a suit as you describe would make simple jobs difficult, and mediocre jobs impossible. Since the enviroment on Mars will be fairly similar to Earth, lightweight, MCP suits will no doubt be the uniform of the day for most topside work.<br /> <div class="Discussion_UserSignature"> <p style="margin-top:0in;margin-left:0in;margin-right:0in" class="MsoNormal"><font face="Times New Roman" size="2" color="#ff0000"><strong>Our Solar System must be passing through a Non Sequitur area of space.</strong></font></p> </div>
 
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JonClarke

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Hi Mental<br /><br />Thanks for the nice comments <img src="/images/icons/smile.gif" /><br /><br />I was under the impression that Gemini astronauts removed their suits after launch, wearing them only for launch, landing, and EVA. But I can't find anything specific, apart from a passing reference to lightweight removable suits with G-7. Maybe some crews stayed suited, others removed them.<br /><br />My friend who did his PhD on MCP gloves is manager of the MarSkin project, so it is good to see it mentioned. <br /><br />I like the idea of a two stage airlock.<br /><br />One additional factor is cabin pressurisation. Daily or even twice weekly EVAs will be incompatible with 1 atmosphere nitrox pressurisation. High EVA frequency would make something like the 0.3 atmosphere nitrox mix used in Skylab mandatory.<br /><br />Cheers<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>
 
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JonClarke

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Hi buck_rogers<br /><br />The suit port idea has been considred quite extensively. The rear of the suit docks with the spacecraft and only the hatch has to be cleaned. the astronauts ingresses and egresses through a hatch, much as in the Russian orlan or Krecht suits. The main advantage of this is the almost complete exclusion of the martian environment.<br /><br />The disadvanatge is that it is incompatible with pure MCP suits. But if isolation from the martian environment is the main concern then it is an option.<br /><br />Hard suits have numerous bearings for each joint. They leak badly and are very vulnerable to wear from dust. They tend to be heavy as well.<br /><br />Power suits have been considered to get round the problems of weight in hard suits. Also powered actuators instead of hands because of the problems with pressurised glove dexterity. the problem is of course they are even heavier, require more power and can fail. What does an astronaut to if the power fails and he is stranded in a suit 100 m from the hab? Do a Dave Bowman? What is the power fails while holding something immovable - does she cut her hand off? <br /><br />i would not worry about mars smelling though. It think it is unlikely, and even if it does, you wouldn't notice it after a day or so <img src="/images/icons/laugh.gif" /><br /><br />Cheers<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>
 
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CalliArcale

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<blockquote><font class="small">In reply to:</font><hr /><p>I like the idea of a two stage airlock. <p><hr /></p></p></blockquote><br /><br />Isn't the Quest airlock basically a two-stage airlock, because like the other modules it can be isolated from the others by closing the hatch between it and Unity? I know they haven't had much chance to use it that way of late, with most spacewalks being done from Pirs (which I think can only work as a single-stage airlock, but I'm not entirely sure about that). But I believe they can seal themselves into Quest, reduce its pressure to help them prepare for the EVA, pre-breathe pure oxygen in shirtsleeve comfort, and *then* suit up before moving to the actual airlock. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>
 
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silylene old

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<i>i would not worry about mars smelling though. It think it is unlikely, and even if it does, you wouldn't notice it after a day or so </i><br /><br />Given the soil compositions, I would expect a noticable odor with components of sulfur, astringency, ozone and bleach. I base this upon sulfur and peroxide compounds I have handled as they interact with humid air. I agree, the nose would adapt to the odor, and it would be unnoticed except for perhaps a minor irritation of the mucous membranes and eyes.<br /><br />I also think the astronauts would taste the odor and dust as particles and odors are inhaled. Your tongue doesn't adapt to taste very well, so I expect this taste sensation to persist a lot longer. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>
 
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astrophoto

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Pressure tents. I dont know, just thinking out loud. Would it be feasible to build a tent-like structure that can be moved from place to place, set up in an hour or two, and have an 'open floor' where scientists/astronauts can dig and work without wearing heavy duty suits?
 
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bobw

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That could probably work if it had a glove box type thing in the floor. Otherwise I don't think you could seal the walls to the ground in an hour or so. <div class="Discussion_UserSignature"> </div>
 
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astrophoto

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My thoughts are that if there was a mobile lab of sorts, that could be set up on flat terrain, then we could design two suits. One a heavy duty pure-exposure suit that has restricted mobility (and thus doesnt need to be totally re-engineered from current technology) and a second suit that is a more flight-suit which the workers could use in a not-so-hostile mobile tent environment.<br /><br />I wonder what operating pressure a thin suit could work with on Mars and keep the health effects off of the human workers, then we could figure out what sort of pressure the tent would need to provide, then we could figure out how to design the pressure creation and seal creation requirements of such a tent. Might be simpler than some alternatives, and supply a comfortable working environment for scientists.
 
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bobw

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I think you would need some pressurization anyway for convective and conductive heat. Radiant heat, like those panels they put up in warehouses, is hot on one side and cold on the other and uncomfortable. Without some atmosphere the suit would need coolant loops, like spacesuits, making it heavy and power hungry. It seems like making the tent good enough for a really light suit, like a skindiving wet suit and oxygen mask or helmet, would make it so you don't need the suit anyway.<br /><br />Maybe if you had dual skirts, like on a hovercraft, heaters, etc. you could set your building down and use water to make the seal. Let it soak into the ground or contain it on rock, freeze it up and it might be able to hold some air for a shirtsleeve environment.<br /> <div class="Discussion_UserSignature"> </div>
 
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JonClarke

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Hi silylene<br /><br />Sulphates like epsomite and gypsum don't smell. The composition of the oxidising element in the regolith hasn't been identified, but is probably not peroxide. Also the hab will have an efficient air filtration sysem to clean out the dust anyway, simply to keep dust out of lungs and electronics.<br /><br />Cheers<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>
 
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bobvanx

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I got the sudden visual of a big, soft, pressurized ball. It'd have a docking port that would be blown free of dust from Martian CO2 to help isolate the Martian environment. The Martian would get inside and walk around. At an interesting location, he or she would use glove-box type gloves to manipulate objects outside the ball. Gloves could be less insulated, since the hands would be in them for limited periods, so tactile sensation might be higher. A rover would tag along, as a mobile toolbox.
 
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astrophoto

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Whats the invention called that was supposed to change our lives ... the thing with two wheels that moves people around and up stairs, etc. It would be interesting to adapt something like that for the Moon and Mars. I know part of our issues exploring there is being able to move around easily without falling over.
 
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