DIY Mars Debrief: The Meaning of a Pressure Test, part 2

Posted: Oct 24, 2013 10:49 am EDT

(Tina Sjogren) Last we left off, Cameron was at a Danish rocket shop strapped in the torturous Kazbek Position, listening to the sounds inside a pressurized space suit he'd built himself.  "I am hyper-aware of my vital functions and the fact that my life is completely dependent on machinery," he recalled. Here goes part 2 of the debrief.

  

Copenhagen Report:

The Meaning of a Pressure Test

Cameron M. Smith 02 October 2014

 

John crackles across the radio again:

"OK Cam let's go over the Emergency Egress procedure. Coming up on 41 minutes in the Kazbek position."

My fingertips and toe-tips are numb.

"Yeah John," I say, keying the radio button in my right hand, "I have some, ah, some numbness in my toes and fingers. You catch that? Some numbness in hands and feet.” 

 

Something is wrong with my posture, or the seat design, or the suit design, because we shouldn’t have such issues. This is why I’ll spend the next couple of years integrating my suit design with the Copenhagen Suborbitals capsule.

 

A long pause, and then John comes on again:

"OK numb in the toes and hands. OK, what do you think about an Emergency Egress procedure?"

"All well," I say. We've been here a while but I'm not giving up without trying an emergency escape test! I fidget in my seat, adjusting my shoulders, noting where some padding will be needed beneath my shoulder blades.

"OK," John says, his voice fragmented by static, "I'm going to give you two taps on the helmet when it's time to get out. We'll skip the checklist."

 

 

"10-4," I radio. Checklists, we’ve learned, change from day to day because we do new tests daily. John and I  try to keep up, but, unlike NASA a generation ago, our well of resources is not endless.

 

We can only work so many hours a day and inevitably sometimes we skip checklist items, or entire sub-checklists, and go by the gut. I know John doesn't like it, and I don't like it and I know that over a beer later we’ll simultaneously mutter "We've gotta stick with the checklists."

 

John through the radio: "Ok, pressure's good, temperature's good, breathing gas is good. All ready to come out?"

 

Now my heart runs fast. The hatch on Copenhagen Suborbital's Tycho II capule is 55cm wide -- just wide enough to get the shoulders, the widest part of the body, out. Earlier tests have taken over a minute for me to wrestle my way out, far too long in the event, say, of a fire, or a capsule No-Parachute Scenario, the nightmare of nightmares.

 

After a pause, John asks,

"How're you doing, Cam? Ready to come out? Remember, two taps and you get out."

 

I go over my systems. Is my temperature OK? Yes, the ice water flowing through fifty feet of tubing, sewn by hand into my liner suit is keeping me cool.

 

The human body runs at nearly 100F and simply pours off heat that, in a pressure suit, has nowhere to go. Only the ice water hurrying through the tubes in my suit and carrying away some of the heat keep me from cooking alive. Before we perfected the coolant system, back in Oregon I once had a combined heat and humidity index of 130F in the suit, which just about knocked me out.

 

But today All is Well, after melting two liters of ice in the first 30 minutes John recently replenished the coolant reservoir and I am feeling just fine. How about my pressure? I crook my arm and spy the big clunky gauge: yes, just where we want it; a pressure sufficient for bailing out at 40,000 feet.

 

Breathing gas flow OK? I take a deep breath, inhaling a glorious lungful of icy-cold compressed gas. All Well. “Com check,” I say and John instantly replies “Good comms,” and I shoot back "OK good comms, good pressure, good temperature, good BG flow."

 

"Waiting for two taps."

 

Tomorrow: Final

 

Previous entry

 

 

#Space

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#Polar 

"My fingertips and toe-tips are numb."
courtesy Photo: Jev Olsen, SOURCE
"I know that over a beer later we’ll simultaneously mutter 'We've gotta stick with the checklists'."
courtesy Photo: Jev Olsen, SOURCE
"I crook my arm and spy the big clunky gauge: yes, just where we want it; a pressure sufficient for bailing out at 40,000 feet."
courtesy Photo: Jev Olsen, SOURCE
Altitude chamber test
SOURCE
Immersion test
SOURCE