Does 3.5 G is big?

[Pawelk198604]

I find interesting video on youtube about soyuz capsule

Watch on 7:45, it says that during launch phase consonants experience 3.5 G, does is high, i wonder does i will pass-out on 3,5 G. I know that some rollercoaster in America and Europe, and yet kids as young as 13 years old ride on them:D

[Spica]

I've experienced 3.2 G for over 30 seconds in a centrifuge, and I didn't have any trouble remaining conscious, and neither did anyone else there have any problems with blacking out. However, those cosmonauts are experiencing 3+ G for much longer, so that might make a difference.

[lajoswinkler]

Pawelk198604, how about "Is 3.5 G a lot"? You're using the Internet which is mostly in English language. Have you ever seen a phrase "does x is big"? Come on, it's not so hard.

No, 3.5 is not a lot, that's a standard peak acceleration in common rollercoasters, drop towers and other gravity rides. Some go a bit over 4 G, but those are shortlasting peaks.

It's scary if it's your first time, but when you learn how to control your guts and breathing, it's great fun.

[xenomorph555]

3.5 g's is NOTHING, vostok pilots went up against 8 g's on reentry. Every spacecraft launch is about 3 g's.

[Godot]

Isn´t the shock during landing (when the retroboosters fire a few meters above the ground) even higher than 3.5 G? (like ~5G)?

[Javster]

I've never experienced it, but for spaceflight, or even for normal flight, I don't think it's that much.

[Skyler4856]

Ive endured up to 5g, albeit for a few seconds, and Ive experienced 3g for something like 20 seconds, from my experience I would say the force isn't absurd.

[cantab]

Yeah, 3.5 g isn't a problem for a healthy person. Though you'd probably need training to be able to reliably operate a spacecraft under it. It takes 5 g or so for there to be a serious risk of blacking out. Orientation matters too; lying on your back you can handle more.

[AngelLestat]

The G force resistence depends on the exposure time.

Maybe you find that between 9g-10sec, 6g-25sec, 3g-2min, 1.5g-15min, 1.2g-2days are all similar in resilience.

For example people may think that mars gravity of 0,3g may not present any risk to our health, but depends on time, maybe that G in 10 years ends being mortal. Or with serious consecuences in a young person development.

[Seret]

Isn´t the shock during landing (when the retroboosters fire a few meters above the ground) even higher than 3.5 G? (like ~5G)?

For that kind of thing what's most relevant isn't the peak g force, but the rate of change in g. This is known as jolt force. 5g applied in 0.01s is a lot more severe than 5g over 1s, for example.

Things like ejection seats and parachutes are limited more by jolt force considerations than peak g. You can pile on a lot of g for a short period as long as you don't pile it on too quickly.

Edited August 25, 2014 by Seret

[linkxsc]

The G force resistance depends on the exposure time.

Maybe you find that between 9g-10sec, 6g-25sec, 3g-2min, 1.5g-15min, 1.2g-2days are all similar in resilience.

Resilience to what? Blacking out? Fairly sure that if you shifted to a 1.2g environment, a healthy person would feel much heavier, but it likely wouldn't just be like "2 days gone by, time up time to pass out". Anything below 2Gs would probably be manageable to live in, and even perhaps might be beneficial in some applications. Someone for example who lived on a station simulating 1.5Gs for a couple years, moving around and going about their business, then going down to earth and only seeing 1G, might almost feel superhuman in strength. While a person coming from earth might have a lot of trouble adapting to life in a 1.5g. But you know, given a year to build up the strength, then they'd be just like the person coming down.

Although, it'd be much more effective if the gravity were adjusted over time rather than a sudden jolt change.

On the note of mars. Well any majorly different gravity would have major changes on development. Someone raised on mars wouldn't need to be as strong, or have anywhere near the bone density or heart strength. Likely if someone lived there for 10 years and adapted to that environment, they might find that they're unable to return to earth simply because to them, earth would be ~ "3gs". But hey there hasn't been much experimentation on that yet. Id say forget messing with Mars and instead go for a moon base to get the first major test data of people living extended lives in a different gravity (besides, on the moon, they're literally a couple days flight away encase anything happens, and they might have some actual work to do while they're there). Rotating space station might also be a good way (but much better for testing the higher G situations).

I honestly do wonder though. The Human body is amazingly adaptable, and even in my own state, between summer and winter I get vast differences in my own physical fitness level (start of spring, I can probably do a 20 minute mile, and then flop on the ground and be done for the day. Winter bear fat and all that. End of summer, I'll have often gotten down to a 8min mile, while carrying ~50lbs total of airsoft gear, my shield, and occasionally a forest stormtrooper costume for the lulz, and I'll have run 3-4 marathons or half marathons. Sometimes I wonder what I could be like if I kept the same activity level through winter, but I tried the gym thing and it really wasn't for me.) Trained soldiers also baffle me in their endurance and conditioning. Hell people do ultra-marathons. They just run, 50 damn miles... for FUN. Put 1 of them on mars, and watch them go. Don't even need rovers, they could just run, jump, maybe fire a little compressed gas thruster for a little vertical boost to slow their decent. Cover a football field in 2-3 jumps.

I would hope to see in my lifetime, a large enough station with a rotating gravity block large enough for people to live for years. Start it off at 1G, and gradually speed it up by .5Gs a year, while studying the people living on it. Could a person survive sustained 1.5-2Gs? Probably, but you'd probably have major back problems. Andre the giant was literally too heavy for his bones and heart to support towards the end of his life. And a 200lb person at 2Gs would basically feel like him.

[Jesrad]

Sailplane flying will subject you to 4Gs quite routinely. Those spiral paths into thermal ascensions can be tight. Anyone can do it.

[Godot]

Actually even the 5G that I mentioned for the cushioned landing of a soyuz isn´t the worst thing.

There have been cases of 8G descents (due to misplanning/problems during rentry).

Like described here (in which the Kosmonauts and Astronaut experienced the 8G for the duration of a minute):

http://www.chron.com/news/nation-world/article/U-S-astronaut-recalls-terrifying-Soyuz-descent-1759455.php

[mrfox]

Actually even the 5G that I mentioned for the cushioned landing of a soyuz isn´t the worst thing.

There have been cases of 8G descents (due to misplanning/problems during rentry).

Like described here (in which the Kosmonauts and Astronaut experienced the 8G for the duration of a minute):

http://www.chron.com/news/nation-world/article/U-S-astronaut-recalls-terrifying-Soyuz-descent-1759455.php

One upping that one would be the launch/abort of soyuz 18a, which did 21.3Gs during the abort maneuver!

[KerikBalm]

It depends on the position that the occupants are in...

3.5 G is a lot worse if you are standing up instead of laying down (assuming the 3.5 G is in the "down" direction).

Having personally experienced 6.3 G, and started to have vision problems then (upright seated position, the G's forcing blood from my head to my feet), I'd say, no, 3.5 G is not so bad. I wouldn't want to live in it though, but a few minutes... no problem

[cpast]

One upping that one would be the launch/abort of soyuz 18a, which did 21.3Gs during the abort maneuver!

Older ejection seats had similar levels of acceleration. When the alternative is essentially certain death, the risk of severe injury becomes much more acceptable.

[NERVAfan]

airly sure that if you shifted to a 1.2g environment, a healthy person would feel much heavier, but it likely wouldn't just be like "2 days gone by, time up time to pass out". Anything below 2Gs would probably be manageable to live in

People have put rats in centrifuges for two weeks. There were some effects (bone changes, newborn rats grew slower), but they didn't keel over dead or anything

http://www.ncbi.nlm.nih.gov/pubmed/10776448

http://www.ncbi.nlm.nih.gov/pubmed/10776449

http://www.ncbi.nlm.nih.gov/pubmed/12124181

However, major caveat there -- small animals can get away with things big ones can't. So it might be worse for humans.

Drop a mouse off the Empire State Building and it should land safely (unless a hawk grabs it on the way down) -- it's small enough that its surface-area-to-mass ratio is is high, giving it a low terminal velocity. (Cats are borderline -- they are well known to sometimes survive very long falls, but they break bones, and some do die.)

On the note of mars. Well any majorly different gravity would have major changes on development. Someone raised on mars wouldn't need to be as strong, or have anywhere near the bone density or heart strength.

Well, if you were walking around on Mars with a spacesuit, the total weight wouldn't be that much less than a person on Earth - current spacesuits are very heavy.

There is work on much lighter ones though so by the time we get there, who knows?

Also, you could just wear weights (some kind of harness distributing weight around your body) to keep up your strength (have earthlike weight) while in the pressurized habitats etc.

[Rickenbacker]

Would have to be a hell of a thermal to let you sustain 4G, though . But yeah, you routinely pull anywhere from 2 to 4G when first entering a thermal. Depending on how small it is, you might end up in a 1,5-2G sustained turn to stay centered, but I can't say I've ever had to pull more than that. In a normal-ish size thermal I'd usually just coast around in fairly lazy turns, with no real G load unless changing direction.

3,5G isn't too bad if seated in a reclining position, you can probably stay conscious indefinitely, though you'd get tired pretty quickly from just breathing. The only time I've ever experienced greyout (loss of color vision and peripheral focus) was when my aerobatics instructor pulled a 5G loop entry and I wasn't prepared.

[Jesrad]

It has nothing to do with the strength of the thermal, and all to do with how tight a spiral you wound. Of course a mere +2 m/s ascending rate won't let you gain altitude at that tight a turn...

<= ascended from a cement factory thermal