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#1 2019-09-10 13:27:49

Oldfart1939
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Registered: 2016-11-26
Posts: 2,306

An astronaut is urging NASA to form new spacesuit program

Here's an article from Business Insider in this regard:

https://www.businessinsider.co.za/astro … ing-2019-9

That was the crux of a message by former astronaut Sandra "Sandy" Magnus to a NASA gathering in Houston, of safety experts. Mentioned also was the present condition of the now 40+ year old EVA suits onboard the ISS; old and deteriorating.

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#2 2019-09-10 16:22:46

louis
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From: UK
Registered: 2008-03-24
Posts: 7,208

Re: An astronaut is urging NASA to form new spacesuit program

I couldn't find anything about spacesuits in the Space X careers section but there are plenty of interesting open posts.


Oldfart1939 wrote:

Here's an article from Business Insider in this regard:

https://www.businessinsider.co.za/astro … ing-2019-9

That was the crux of a message by former astronaut Sandra "Sandy" Magnus to a NASA gathering in Houston, of safety experts. Mentioned also was the present condition of the now 40+ year old EVA suits onboard the ISS; old and deteriorating.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#3 2019-09-10 17:19:35

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 26,787

Re: An astronaut is urging NASA to form new spacesuit program

This goes back to the balloon suits which were not problem free and still did not pertect the individual wearing it as seen from the toes and fingers from the past apollo lunar missions.

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#4 2020-08-02 10:16:10

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 26,787

Re: An astronaut is urging NASA to form new spacesuit program

How Space Suits Work

The EMU consists of the following parts:

•Maximum Absorption Garment (MAG) - collects urine produced by the astronaut
•Liquid Cooling and Ventilation Garment (LCVG) - removes excess body heat produced by the astronaut during spacewalks
•EMU Electrical Harness (EEH) - provides connections for communications and bio-instruments
•Communications Carrier Assembly (CCA) - contains microphones and earphones for communications
•Lower Torso Assembly (LTA) - lower half of the EMU including pants, knee and ankle joints, boots and lower waist
•Hard Upper Torso (HUT) - hard fiberglass shell that supports several structures including the arms, torso, helmet, life-support backpack and control module
•Arms
•Gloves - outer and inner gloves
•Helmet
•Extravehicular Visor Assembly (EVA) - protects the astronaut from bright sunlight
•In-suit Drink Bag (IDB) - provides drinking water for the astronaut during the spacewalk
•Primary Life Support Subsystem (PLSS) - provides oxygen, power, carbon dioxide removal, cooling water, radio equipment and warning system
•Secondary Oxygen Pack (SOP) - provides emergency oxygen supply
•Display and Control Module (DCM) - displays and controls to run the PLSS

The new space x suits are quite stylish.

EMU Facts



•Weight = 280 lb (127 kg) on Earth
•Thickness = 3/16 in (0.48 cm), 13 layers
•Atmosphere = 4.3 lb/in2 (0.29 atm) of pure oxygen
•Volume = 4.4 to 5.4 ft3 (.125 to .153 m3) without astronaut
•Cost = $12 million each
•Contractors - Hamilton Sundstrand, ILC Dover

yah its no MPC suit for mars.

The Materials Used in Space Suits
The modern space suit is composed of 14 different layers of material which all contribute in their own way to the survival of the astronaut.

ImageForArticle_12007(1).jpg

The MIT BioSuit

lots of images

http://www.madehow.com/Volume-5/Spacesuit.html

spacesuit layering images

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#5 2020-08-13 12:19:18

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,952
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Re: An astronaut is urging NASA to form new spacesuit program

My own opinion is that having one garment do everything you could possibly want is the wrong approach.  The MIT biosuit suffers from that. 

What you want is vacuum-protective underwear coupled with whatever insulating and reflective outerwear suits the job at hand.  If you look at the original "space activity suit" of Dr. Webb,  that is his fundamental approach.  It leads to a simpler,  lighter,  far less restrictive suit,  and one which is launderable in the normal ways. 

Rather than make it expensive with exotic tailored materials the way MIT did,  keep it simple like what Webb did.  Myself,  I'd combine Webb's tight stretchy fabric ideas with the capstan-tensioning of the old partial pressure suits.  That greatly eases the doff-and-don problem of Webb's tight-fitting layers.

But key here is just building the vacuum protective underwear.  Insulated coveralls,  gloves,  and hiking boots you can buy at places like Walmart. They work just as well in vacuum as they do in air.  Why build all that into your pressure garment,  when you absolutely do NOT have to?

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#6 2020-08-13 19:37:53

kbd512
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Re: An astronaut is urging NASA to form new spacesuit program

GW,

How many gloves from Wally World function acceptably well from -250F to +250F?  Has anybody ever tested that?

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#7 2020-08-14 12:08:05

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,952
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Re: An astronaut is urging NASA to form new spacesuit program

I doubt anybody has ever tested it.  But it would some really easy testing to do. 

Welding gloves are very protective against hot stuff.  Even just thin plain leather gloves do a good job,  if the heat is not too extreme.  Been there and done that myself. 

I dunno,  but if they are that good going hot,  they ought to do some sort of a decent job in the cold. What you have to watch out for going cold is skin moisture freezing,  bonding the glove to your hand.  It's why the gloves for cryogens are not to be used when handling non-boiling cold liquids (or solids like dry ice).  The freezing together of hand and glove is a very serious frostbite risk.  It's why you pick up dry ice blocks with newspaper,  not gloves.

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#8 2020-08-14 17:19:51

SeaDragon
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From: Merry Old England
Registered: 2020-07-25
Posts: 32

Re: An astronaut is urging NASA to form new spacesuit program

I've been thinking about equipping clothes only for basic vacuum safety but designing them primarily for full pressure comfortable use. In "shirt sleeve" situations a baggy garment designed to slightly inflate upon exposure to vacuum might provide good standard wear. It's not so hard to design flexible and comfortable suits that stretch out and become rigid in vacuum - your mobility is greatly limited and it's no substitute for a proper space suit but you can still move to some degree and, most critically, you don't immediately die or get limb damage if your habitat suddenly depressurises (providing a quick deployment of helmet is also possible).

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#9 2020-08-14 17:52:24

SpaceNut
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Re: An astronaut is urging NASA to form new spacesuit program

The reason for the counter pressure is to reduce the person bloating.

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#10 2020-08-15 10:14:30

GW Johnson
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From: McGregor, Texas USA
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Posts: 4,952
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Re: An astronaut is urging NASA to form new spacesuit program

The real reason for pressure on the body is to counterbalance the pressure in the lungs that is required to successfully diffuse oxygen from the lung spaces into the blood,  which is at pressure,  as long as the heart beats.  The lungs are very easily damaged by too much inflation pressure (2 psi differential is enough to rip them fatally).  It takes at least 2 psi pure oxygen feed to the lungs to keep a person functional.

You put the counterpressure on the body to match that inside the lungs rather closely.  Doesn't matter whether it is applied as gas pressure on the skin inside a full pressure suit,  or as mechanical pressure on the skin,  as in the the old partial pressure suits.  That is because the body is much like a water balloon.  Squeezing it mechanically raises the pressure inside it.

If you choose mechanical squeeze,  you need to do it relatively uniformly.  Otherwise after a period of time body fluids and blood migrate internally from the parts under more compression to the parts under less compression.  This causes swelling,  which is the "bloat" Spacenut spoke of.  The technical term is "edema".  It takes about 30 minutes exposure for an uncompressed hand to start visibly swelling.  The pain of this renders the hand unusable once the hand swells up.

The old partial pressure suits left hands and feet uncompressed,  and lacked sufficient compression on legs and arms relative to that applied to the torso.  Blood pooling into the legs would cause fainting after about 10 minutes,  but that time was adequate to bail out and free fall from altitudes exceeding 70,000 ft,  with pressure breathing in the helmet.  The Armstrong limit is commonly used as the "vacuum deathpoint":  63,000 feet.  A plain oxygen mask won't work above about 40,000-to-45,000 feet,  you must do pressure breathing up there.  Which means you have to counterbalance the breathing pressure with compression upon the body.

The 6-7 layers of tight pantyhose material,  that Dr. Webb experimented with in the 1960's,  provided much more even compression than the partial pressure suits with inflated capstan tensioning.  Not perfect,  but good enough to avoid edema problems.  His final demo test in 1968 had a man wearing the garment (and nothing else),  with oxygen helmet and a simple oxygen backpack,  peddling a bicycle ergonometer,  for 30 minutes in a vacuum chamber,  at a simulated 87,000 feet (way above deathpoint).  No cooling was required,  other than sweating right through the porous material into vacuum.  I think he was using 190 mm HG (3.67 psi) as the breathing oxygen pressure in the helmet. 

In the test,  the subject breathed though a hookah line,  the backpack was there as dead weight to be carried.  Garment,  helmet,  and backpack weighed an astonishing 85 pounds.  The subject could easily climb ladders,  wedge into tight spaces,  and crawl under and through tight spaces.  A set of white reflective insulated coveralls would add about 5 pounds to that at most.  Add 2 more pounds for some leather hiking boots,  and maybe a pound for some leather gloves,  welding gloves at worst.

You're talking about a spacesuit under 100 pounds in toto (!!!!),  which does NOT restrict freedom of movement,  and which can be easily taken apart and laundered.  Webb did this as a candidate for the Apollo moon EVA suit,  but could not get the development done in time to go.  Its biggest disadvantage was its fundamentally-required tightness that made donning and doffing the suit difficult.

My idea was to combine his elastic fabrics with the capstan tensioners of the old partial pressure suits.  Relax the tension to doff and don,  inflate the capstans to draw tension. Let the elastic nature of the fabric distribute the compression evenly,  just like it did in Webb's design. Now you have all the advantages,  and got rid of the disadvantage,  of MCP.

You won't always be doing the same work in the same places under the same conditions.  Your needs for insulative protection will vary.  So choose the unpressurized outerwear that suits what you are doing,  and treat the MCP garment as vacuum-protective underwear.

The design-everything-into-the-one-spacesuit idea is just plain wrong.  It's the wrong box constraining thinking for about 60 years now.

GW

Last edited by GW Johnson (2020-08-15 10:22:36)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#11 2020-08-15 11:03:17

kbd512
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Re: An astronaut is urging NASA to form new spacesuit program

GW,

The designs tend to look like variations on the same theme because they're after a specific result- a "single person spacecraft".  I've heard and read that phrase from numerous people inside of NASA.  We need this space suit design to do something it can't, so let's run the experiment again and hope for a different result.  It'll be different "this time", because we spent more money, had newer materials to work with, had smarter engineers, etc.  The US military does the same thing.  We need this new weapon system to do "X", but it can't do "X" by design, so let's squander some more tax payer money to see if that changes anything.

They're not actually trying to solve the problem.  They're waiting for some new miracle technology to come along, that they will "invent"- thus proving how "smart they are", rather than "how practical they are", to solve an otherwise simple problem that doesn't require a multi-decadal science experiment to fascinate engineers who are more fascinated with conducting science experiments than developing practical solutions.

All of life doesn't need to be a giant science experiment intended to stroke egos and spend money.  Sometimes you just need to get things done as simply and expeditiously as is feasible.  The space pen is a poster child for this type of thinking.  Sure, we had a million bucks to spend on the design and it's great that it actually works, but the Russians used grease pencils and spent the million dollars not spent on space pens to solve more pressing engineering problems.

Being wrapped in 10 pounds of Playtex pantyhose fabric isn't nearly as whiz-bang as "single person spacecraft".  That's the basic problem.  However, 10 pounds of pantyhose actually worked, it worked shockingly well, and the minor problems were discovered and ironed out.  We have shoehorns to help riders put on very tight-fitting boots, so we need "suithorns" to put on body hugging space suits.

If it were up to me, we'd do exactly what you proposed doing and dump all the remaining money into making the batteries and life support equipment as durable and reliable as we feasibly can.  Great strides have been made in life support equipment on a comparative shoe string budget, whereas space suit design is still stuck in the Apollo era.

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#12 2020-11-02 21:40:21

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 26,787

Re: An astronaut is urging NASA to form new spacesuit program

Happened upon this post...

karov wrote:

this

31TG0kshxxL._SY300_.jpg

made of something like this

http://www.sciencemag.org/content/343/6173/868

(with powersource)

will be enough to conquer and thrive into much more then 1.7 gees environment.

it won't be a exosceleton precisely, but rather octopus-like external kinetically self-supporting musculature.

this covers the options of living there whole lives without 1. genetic modifications and/or 2. cyborgization or 3. "technological metempsychosis" ( body to body "soul" uploads).

All: 1, 2, 3 are reversible and temporary, not more "supramundane" or speciating then using other exosomatic tools - like garments, glasses, etc.

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#13 2020-11-03 17:49:58

Oldfart1939
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Registered: 2016-11-26
Posts: 2,306

Re: An astronaut is urging NASA to form new spacesuit program

kbd512 is absolutely correct when he states suit design is still stuck in the 1960-1970 era of Apollo program--as is the other white elephant in the room--SLS.

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#14 2020-11-03 22:45:54

kbd512
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Posts: 6,238

Re: An astronaut is urging NASA to form new spacesuit program

Oldfart1939,

Unless NASA's engineers pursue a hard divorce with NIH thinking, we're not going back to the moon because they keep trying to fit round pegs in square holes.

We have a rocket that works - SpaceX's Falcon Heavy.  SpaceX has reduced booster reusability to engineering practice.

If on-orbit refueling and long duration cryogen storage works, then we have upper stages for that - ULA's ACES.  Any LOX/LH2 engine can be refueled using water ices locked up in lunar regolith.  The O2/H2 combustion engine or fuel cell can provide electrical power and drinking water.  Apart from on-orbit refueling, we have everything else so thoroughly tested that it's reduced to engineering practice.

The Dragon II / Dragon Rider space capsule is purported to be exploration-rated, has been extensively tested, and is about to see it's first fully operational mission.

If on-orbit refueling or long duration cryogen storage doesn't work, then we still have an upper stage - Merlin Vac Upper Stage or Raptor Vac Upper Stage.  Irrespective, we have three perfectly viable TLI options for lunar exploration and long duration space flight away from Earth's protective magnetosphere.

We have a spacesuit design that works in the lab - MCP.  This is the only practical space suit for strenuous physical activity over hours of EVA duration.  Beyond that, it can't suffer from a fatal decompression event by being ripped or punctured.  So long as duct tape still works in space, then that's an immediate quick-fix for a ripped suit.

We have multiple feasible lander designs that could work, but the most practical near-term lunar lander design comes from Dynetics because it has the correct geometry to prevent it from tipping over during an off-nominal descent.

So...  We need to focus on practical solutions that could actually work in the near term, rather than proving how clever we are when money is no object.

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#15 2022-09-24 10:48:19

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 4,782

Re: An astronaut is urging NASA to form new spacesuit program

How to put on a Feitian EVA spacesuit

https://twitter.com/CNSpaceflight/statu … 8561383424

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#16 2022-09-24 12:34:01

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,306

Re: An astronaut is urging NASA to form new spacesuit program

We will soon see how effective the new extravehicular activity space suit that SpaceX has constructed will work on Jared Isaacman in the next Polaris mission. HIs spacewalk should leave NASA engineers with their heads hung in shame. SpaceX has an "outside the box" mental attitude, and one that focuses clearly on problem solving. The latest NASA suit is a hideous nightmare, and is clearly not as good as the Apollo Era suits for mobility and ease of getting around.

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#17 2022-09-24 14:54:08

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,952
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Re: An astronaut is urging NASA to form new spacesuit program

A part of the problem is that NASA and its favored contractors insist on using the "alveolar gas equation",  to model blood oxygenation.  There are typically 2 terms,  one the water vapor displacement effect that requires NO assumptions,  and the other modeling the combined effects of CO2 displacement and dead-end gas displacement,  in the alveoli.  That second term requires two assumptions,  one of which we have long known is bad.  But THAT is what has led to the proposed 8 psi space suit designs on pure oxygen!

You do NOT have to do that!  We have known since the Project Mercury days all the way through Skylab that a 3.7 psi pure oxygen space suit is quite adequate. 

You do not even have to have that much suit pressure!  The vented oxygen mask data for pilots,  cognitive enough to fly jet aircraft in combat (!!!) at altitudes up to 45,000 feet,  say that pure oxygen at about 2.6 psia in the mask is more than enough,  for flight times up to several hours!

Military pilots have been even higher than that (50-55,000 feet),  on nothing but a vented oxygen mask,  but only for several seconds in a zoom climb transient. That's not enough exposure time to suffer noticeable hypoxia.

There is an issue with drying out lung tissues in pure oxygen at too low a pressure,  if the exposure becomes many hours (like a whole day).  That limit is fuzzy,  but is already known to be somewhere in the vicinity of 3 psia.  In other words,  a 3 psia pure oxygen suit (of any kind) is more than adequate for all-day EVA activities! 

Webb did his work closer to 3.7 psia than 3 psia.  Dava Newman did the same.  These lower pressures make MCP feasible.  The higher pressures (4+ psia) render it infeasible with known technologies.

The other issue is getting the bends going from near-sea level pressure and composition to low pressure in a pure oxygen suit.  If you meet the no pre-breathe criterion,  this is not a problem.  That is partial pressure of nitrogen in habitat air,  divided by 1.2,  equals the minimum pure oxygen suit pressure.  That's the min value.  Anything higher for your suit pressure is OK with no pre-breathe time.  That criterion was adapted by NASA from US Navy dive experiences over many decades,  to the far lower pressure environments that we have with space travel. 

We had experience with Skylab lowering total pressure to only 5.0 psia,  at 74% oxygen by volume,  in a 2-gas mix with 26% nitrogen.  That worked just fine for astronaut crews up to 84 days continuous exposure.  There were no problems with getting the bends decompressing into a 3.7 psia pure oxygen suit for EVA's.  It does fail an Arrhenius reaction rate model for fire danger,  but only by 20-something percent predicted burn rate.  The min suit pressure for no pre-breathe was 1.08 psia,  which we already know is too low.

We already know the alveolar gas equation predicts bad values for mountain climbers above 2500 meter elevations in Earthly air.  That is because there is a fundamental shift in human metabolism at that critical altitude in Earthly air.  Below it,  the body holds blood CO2 concentrations constant,  and lets O2 concentrations float to whatever prevails.  Above it,  the body tries to maximize O2 blood concentration by hyperventilation,  and no longer controls blood CO2. 

Assuming that the lower altitude blood CO2 concentrations is what also happens at higher altitudes,  is the fundamental mistake people make applying this equation.  The hyperventilation drives one into very low blood CO2 concentrations,  which is the definition of "respiratory alkalosis".  This has been known for decades.  The problem is that no two people respond to high altitude exactly the same way.  Thus there is no agreed-on model for the blood CO2 concentrations at the higher altitudes. 

This same problem extends to other breathing mixtures:  nobody knows what the "right" numbers are for blood CO2 to put into the alveolar gas equation.  Which leads directly to the 8 psi suit recommendation if you use sea-level values.  That is a mistake. 

Now,  Earthly air at 2500 meters is good enough to avoid long-term hypoxia effects like chronic mountain sickness in a measurable percentage of the population.  According to the historical records,  such also is the critical altitude above which there is a measurable increase in childbirth problems.  And it is the altitude where the body shifts from constant CO2 to maximize O2 metabolic behavior.  I find that quite telling. 

Accordingly,  using a 2-gas mix of oxygen and nitrogen,  I have worked out a habitat atmosphere at about 6-to-6.5 psia,  which is 40-45% oxygen by volume,  that gives the same or higher wet in-lung as-inhaled oxygen partial pressure as in Earthly air at 2500 meter elevation.  Using the factor 1.2 pre-breathe criterion on this hab atmosphere yields pure oxygen suit pressures below the 3 psia recommended minimum.  And the oxygen concentration measured in kg/cu.m is below that of 77 F sea level air (0.275 kg/cu.m),  implying that any fires proceed no faster than they would in warm sea level air.

How could we lose?  Long term safe hab "air" to breathe,  fire danger no worse than on Earth,  and a min suit pressure for no pre-breathe time,  that is at or below the min recommended suit designs for full cognition in jet aircraft combat.  Which also happen to make MCP suit designs even more feasible than Webb found. 

THAT is what my convention paper on this topic is all about!

GW

Last edited by GW Johnson (2022-09-24 15:24:07)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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