Monday, November 15, 2010

2+PSI Blowout

Some weeks ago I entirely removed the pressure suit’s first, totally inadequate helmet-suit interface collar, and cleaned all the surfaces with acetone; a week later I glued on a much-improved interface collar, spending a precious eight hours minutely adjusting and gluing the interface as closely as I could, dealing with each wrinkle with millimetric attention and clamping several areas as the glue dried. After this interface glue had cured for a week I made another minute inspection of the interface and applied a number of patches where I suspected problems might arise. I let those patches dry for another week, some of them under clamp-pressure.

Today (Sunday 14 Nov), about a year after the first pressure test, I sealed off all the suit’s through-holes—breathing gas intake, breathing gas exhaust port, and pressurization gas intake—and pressurized the suit. I was thrilled to watch the wrist-mounted pressure gauge rise minutely from 0psi to .5psi to 1psi and then, unbelievably almost, considering all of the potential problems, to 1.5psi. At that pressure, with the suit inflated like a grotesque mannequin, I pressed on the chest—no leaks. To heck with it: like making another move upwards on a difficult climb, even though it might feel imprudent, I sat fully on the suit’s chest, folding up my legs like a guru and applying my entire 180lb weight to the suit; surely this would expose any weaknesses…No leaks! The suit remained pressurized. Fantastic! I stood the suit up—it’s remarkably lightweight—and it remained so rigid that it would even stand entirely by itself, though I’m not sure how that’s possible as the suit’s feet are slightly rounded at the sole! I’ve been dreading pressure-testing the most recent interface collar for some time, telling myself I should let the glue dry another day or two—but this couldn’t have been going any better!

I laid the suit down, thinking that I might do well to give it a name before long. After all, I live with this thing, laying over there on the table, daily, always in view even under its dust-cover sheet, never more than about 20 or 30 feet from me as I cycle through my daily life of cooking or writing or reading, reminding me of the project every day and every night and every morning.

More pressure; was it possible? I kept pumping. The wrist gauge climbed to a hair over 2psi! I was 2/3rds of the way there!

Humans have evolved under about 15 pounds of pressure per square inch (psi) of atmosphere pressing on every square inch of our bodies for the past four million years; we live, one diver has remarked, under an ocean of air, it presses down upon us just as water pressure presses down on a diver who goes further and further down under water. Climb a mountain or go up in an open-cockpit plane or balloon, and less and less atmosphere presses on your body, leading to a number of symptoms; mountaineers call it altitude sickness, and it can result, at altitudes over 20,000 feet, in death as the body swells up like a balloon as less pressure holds the body together. Pop out of a spacecraft into space, where there is zero atmospheric pressure, and the body’s tissues and fluids will in a few seconds simply fly apart, with none of the pressure it’s evolved under holding the tissues and fluids together. Thus, in the last 60 years, the invention of pressure capsules and pressure suits that contain a bubble of pressure about the body, keeping the tissues and fluids all together. A spacecraft, then, is just an elaborate can that is filled with enough gas pressure to prevent the body from flying apart.

You don’t need 15lb of pressure holding you together to survive, however: at the summit of Mt. Everest, at 29,002 ft (8,840 meters), there are only about 5 lb of pressure, and this has been endured by climbers, again and again, who use a variety of techniques to adjust their bodies to high altitudes and the attendant lower atmospheric pressures.

But at 50,000 feet—my target altitude—there are only about 1.7 lb pressing on each square inch; by no estimation so far is this enough to survive. One survivor of an accident in a low-pressure chamber recounts that, just before blacking out, he could feel the water in his tongue begin to boil.

But you can, wearing a garment that can be pressurized (a pressure suit), survive at about 3 psi if (for a number of reasons) you’re breathing pure oxygen. Fair enough; aviator’s breathing oxygen is easily commercially available, and it’s delivered from tanks and regulators in principle identical to SCBUA breathing-gas tanks and regulators, though aviation systems are built for high altitude rather than underwater. I’ve acquired and built these hardware items into the suit. That has been relatively straightforward.

So; my pressure suit needs to hold about 3psi to be workable for my project. I’ve consistently found that the hardware (other than the breathing gas intake and exhale valves on the oral-nasal mask) is not the problem; the problem is maintaining pressure in the pressure garment. And this problem holds not at the gloves or the various gas intake- or out-ports, but at the helmet-suit interface collar. That interface is the chief goblin of this whole project so far.

At somewhere just over 2psi the suit was still holding well. Unbelievable! I’m 2/3rds of the way to a survivable pressure! I pumped a few more times, then; HSSS and the suit deflated, collapsing down rather sickeningly. The suit was face-down at this point, for a number of boring technical reasons, and as pressurization gas leaked from a sudden breach in the interface collar, the suit took on a pretty depressing aspect. Ugh. Watching it deflate brought the reality home: if that happens at altitude, I’ll have little time at all—if any—to crash dive my airship or simply bail out to get down to survivable pressures (say, 20,000 feet, where pressure is normally around 7 psi) before rapid decompression kills me. Damn!

I disconnected the pressurization hose, laid the suit face-up on the table and, as though conducting an autopsy, opened the helmet to examine the interface collar from inside the suit to find the breach. It was immediately apparent; the glue had simply given way at one conspicuous point inside the suit.

So: it’s either re-glue, or take the system apart and rethink and rebuild the entire helmet-pressure garment interface collar. At this moment I think I’ll do the latter. That will take months. Lots of sketching and brainstorming to do; but of course that’s part of the exercise, simply learning how to build my own pressure suit.

The other week I discovered that you can simply buy a pressure suit from the SOKOL company in Russia for about $20,000; and don’t let that low figure (about 1/50th of the cost of a US-built pressure suit) fool you into thinking the SOKOL pressure suit is sub-par. SOKOL suits are in fact, due to a simpler and more robust design, better in my estimation than NASA pressure suits, and they have been delivering and returning cosmonauts to space for over 40 years with not a single lethal failure. The SOKOL pressure suit’s main pressure seal is a simplicity-of-design masterpiece that lightens my soul—the fact that it exists allows me to breathe. I’ll describe it sometime, but for the moment, I can just say that there are human inventions that achieve a great deal but, mind-bogglingly, achieve this not by virtue of their complexity but by virtue of their simplicity. This morning I read an article about Russian gulags of the 1930’s; it reminded me of things I’d read years ago in Babi Yar, an account of a Ukranian boy who survived the German invasion of Kiev during World War II. I’m not sure how to describe it, yet, but I’m convinced there is a connection between the brutal simplicity of Russian gulag thought, Russian materiality and and the SOKOL space-suit’s almost laughable—and entirely adequate—simplicity.

The whole idea that space—which gives us access to nothing less than the whole universe—is cut off from the common person because ‘only NASA can do that’, the whole elaborate and Hollywood-engrained world of ‘The Right Stuff’ is, in my opinion, a sham. Everyone can get into space. The universe does not belong to the military-industrial complex, it belongs to everyone. And building the tools to get there isn’t necessarily a soul-less, flag-waving, militaristic, mechanistic endeavor; it can be done by everyday people, at home, while they listen to Garrison Kiellor describing the sweetness of a different kind of life entirely as they tinker with a valve or a hose-clamp.

Like Russian SOKOL pressure suits, US Navy Mark V suits—entirely adequate for my plans—appear on ebay every once in a while, going for about $10,000, and I have good reasons to believe they’d probably still hold life-supporting pressure. I guess I could come up with that money, but my point is precisely to show that I don’t need to do that: I can do it by myself: such a project isn’t the domain only of the US’s military-industrial complex or the Russian space program, but attainable by me in my apartment on a very modest budget (I have all my receipts, a good many of them from Ace Hardware, but I haven’t bothered to sum them up yet) on Sunday afternoons, while listening to the radio. I don’t want sponsors for this expedition; I don’t want help from the world’s best engineers, who could certainly solve all my problems in a matter of minutes. I want to do it myself.

Learning by trial and error here in the ‘workshop’ is exactly what I’m supposed to be doing. It’s energizing, in an interesting way, to encounter this problem necessitating a rethink of the whole helmet-suit interface design. I’ve found that every time a system has failed, the redesign has been both simpler and better than the first design. This is particularly so with the enormously-problematic oral-nasal mask, which I finally have perfected (after nine rebuilds) by building in two special valves and then, importantly, completely reconsidering and rebuilding the intake and outflow hose routing with an enormously-improved system that ‘came to me’ (a phrase that’s worth serious contemplation) one morning when I was waiting for the tram to work, ‘just’ sitting there on a bench, ‘just’ thinking.

Below, aviation pioneer Wiley Post in his mid-1930's pressure suit, which sustained him to an altitude of 49,000 feet:

So far it’s been about nine months from concept drawings to having the assembled suit ready for that first test; after that it was about a year from that test until today’s test; will it be another year before I achieve and hold the suitable pressure? Maybe, although the problem this time is very limited to just one new interface design. I’m getting there.

Anyway—many months more, then, of brainstorming and endlessly fascinating reading about the principles of bioastronautics and the history of pressure suit design.

Before that can even begin, though, I have to force myself to put this project away and prepare for Alaska. Tonight; restock my medical and repair kits, sew a riser sheath for more easily stowing my paraglider risers while wearing mittens, and, if I can get to it, work on the helmet laser mount.

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