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Last time, I explored how difficult it is for computer hardware to operate in the noisy - from an electromagnetic radiation perspective - environment of outer space. Today’s topic is people. Don’t worry, I won’t be boring you with life support systems. That’s the least of a spacer’s worries. Before you need to worry about …

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Ru
Headmaster

"G-forces are simply acceleration induced by the Earth’s gravity"

Tsk.

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Re: "G-forces are simply acceleration induced by the Earth’s gravity"

that's not pedantic, that's a massive error!

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(Written by Reg staff)

Re: Re: "G-forces are simply acceleration induced by the Earth’s gravity"

True, but the result of a slip of the editor's cursor, not ignorance. The necessary reference to freefall has been put back.

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Re: "G-forces are simply acceleration induced by the Earth’s gravity"

What has Earth's gravity got to do with it other than giving a name to a unit of acceleration that's biologically relevant ?

A rocket far from any gravity source will still generate a force on it's occupants when the engine is running that can be measured in Gs indeed that's an Einstein thought experiment that's used in GR discussions

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Re: "G-forces are simply acceleration induced by the Earth’s gravity"

Still broken.

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Of course... if the body were immersed in water..

The G forces would be mostly canceled except for the lungs.

And if you used fluorinert to fill the lungs (for launch/return) you should be able to go to nearly as high an acceleration as you want.

Might not be that pleasant though.

It isn't the G force that is the problem - it is the difference in support for various densities in the body. Air is really bad at supporting the human body.

Water ? -- proven to work really well for 9 months...

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Unhappy

Re: Of course... if the body were immersed in water..

"Fluorinert" You would of course die from lung trauma.

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Re: Of course... if the body were immersed in water..

Suspect he meant the RL example of perflubron rather than the Hollywood life of Flourinert as used in the Abyss. As noted all the Rat's used in those scenes died of lung trauma and Ed's breahing of Flourinert was SFX.

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Re: Of course... if the body were immersed in water..

Although it works well with rats it's trickier in higher primates because they choke when fluid enters their lungs

So we would need astronauts who can block their gag reflex - LOHAN ?

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Ru
Headmaster

Re: Of course... if the body were immersed in water..

The rats in The Abyss did not drown or die of lung trauma. One died of unrelated causes some weeks after filming. Ed Harris had to hold his breath in a helmet full of water for the liquid breathing shots; nothing special about those effects!

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Re: Of course... if the body were immersed in water..

The problem with using liquids for atmosphere is weight, under the Apollo missions they would reduce the air pressure inside the capsule to 5psi, but increase the oxygen content, to save weight.

I am uncertain if they still do the same thing.

I cannot find the mass for fluorinert, but I would guess it's heavier than air for a given temperature and pressure.

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Coat

Re: Of course... if the body were immersed in water..

I don't think it's that simple. There's an issue with the mass of the body compressing blood vessels and cutting off the flow of blood to various organs (especially the brain inside the skull). There are some mechanisms for counteracting blood pooling in various parts of the body (e.g., legs), such as pressure pants, but I don't know that there is anything that can be done for the brain.

I remember some "science" videos from the 1960s involving rats and fluorinert (or, whatever that Oxygen carrying liquid was). Sheeze, that's been a LONG time ago.

Dave

P.S. Mines the one with the bottle of Oxygen in the pocket.

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Coat

Re: Of course... if the body were immersed in water..

Will astronauts breathing flourinert be chased by the forces of SHADO ?

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Anonymous Coward

Without a shado of a doubt

Interceptors won't work on vashta nerada, you need a tardis.

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Complements Dara nicely

"Dara's Science Club" were looking at space this week (yes, it's considerably less technical than this article, but it's better than nothing!).

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4g Z?

Some roller coasters (e.g. the 1989 version of Scorpion at Busch Gardens in Florida) can get up to 4gs at the bottom of the big drop. And it's Gz because you are sitting up rather than lying down.

At that level you cannot lift your chin off your chest. <---- Voice of experience.

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Silver badge

Re: 4g Z?

There's a ride at Epcot Florida which simulates a launch - I think its gets to 3G for quite a few seconds. It's a centrifuge. Fun, but made me a bit queasy!

http://en.wikipedia.org/wiki/Mission:_Space

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Pint

NASA Centrifuge

I got a ride in a NASA centrifuge decades ago. It took me up to a sustained 3G. The effect was weird, but not too unpleasant, at least until I turned my head sideways. Then, I was hit with a violent wave of nausea (No, I didn't toss my cookies, but it took all my self control to prevent from doing it!). The nausea had something to do with the fluid in my inner ears swirling in an unaccustomed manner. And, I'm not sure how that could be counteracted, at least without a rather substantial dose of Dramamine or something like it.

One of the weirdest feelings was trying to lift my arm, which weighed three times the normal

amount.

I suspect I could have handed a considerably higher G, but I wasn't out to set a record that day.

Oh, the couch was reclined back at a rather comfortable angle.

Dave

P.S. Mine's the one with the beer in the pocket. Doesn't beer counteract space-sickness?

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Stop

Human Pilots?

When I look at these figures, I realize that the legendary Top Guns are going to be looking for other work very soon. It would be much preferable to being shot down by UAV or worse, an Autonomous Aerial Vehicle, such as an advanced type of Globalhawk.

Not only is it now possible to build aircraft that can fly themselves better than humans can operate them, they can hold up better to the forces encountered during aerial combat for longer. All the UAV/AAV needs to do is to stay in a performance envelope that causes its human opponent to succumb. You cannot do anything useful while you are unconscious, but the ruthless machine goes right on flying--and shooting.

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don't forget vibration

excessive vibration is also something that must be managed for human spaceflight. It's one of the biggest issues with the Orion/Shuttle SRB concept.

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why 12 degrees?

Why is 12 degrees from horizontal even better than zero degrees? At zero there would be even less Gz at the cost of a bit more Gx, and we are told that "Gx is a much more pleasant sensation than Gz". Enquiring minds etc.

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Trollface

Gruesome

Anyone else want to know more about the "rather more gruesome tests"?

(Troll face because I've seen what people look like in one of those centrifuges.)

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Thank <deity of choice> for the British

Having now proved the engine technology for Skylon we can all travel to space with no more G force than you'd get on an aeroplane flight.

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FAIL

Re: Thank <deity of choice> for the British

Still needs to accelerate at 3.2G to orbital velocity, there used to be info on their website showing the launch profile.

Longer burn @ reduced G = more fuel = more weight = less payload.

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Thumb Up

Could the Naughts not travel up to the European Space Station at a leisurely pace using the proposed sky lift [Sky hook?] thus the inter stellar craft could leave Earths orbit at a faster pace than if manned and dock at the ESS to pick up the crew?

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TLI

"To end up on a lunar bound coasting trajectory, Apollo astronauts were subjected to three different levels of acceleration, one for each stage of the Saturn V. " Err, no. In Apollo, Trans Lunar Injection required a fourth burn: the third stage was restarted: http://en.wikipedia.org/wiki/Trans-lunar_injection#History

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