> But that just causes a weird feeling, not nausea. Your eyes may be at
> dissonance with reason, but reason is presumably the highest-level
> function of the brain, whereas nausea is among the most fundamental
> functions, that there is no such thing as nausea from a dissonance
> between perception and reason.

Can't they just train the astronauts to not suffer from this type of 
nausea as much? Or at least have it impact their functionality less. 
Being able to launch with slightly less fuel requried seems quite a 
strong goal to me.

IIRC from a course at University on flight mechanics, there is some 
empirical function that estimates a "comfort" level for a human in a 
flying craft. It was some weighted combination of linear and rotational 
accelerations in the various axes. Presumably the people determining 
these sorts of things have access to such requirements, and it's then an 
optimisation problem to use the minimum amount of fuel for a given level 
of "comfort" for the pilots.

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>> But that just causes a weird feeling, not nausea. Your eyes may be at
>> dissonance with reason, but reason is presumably the highest-level
>> function of the brain, whereas nausea is among the most fundamental
>> functions, that there is no such thing as nausea from a dissonance
>> between perception and reason.
>
> Can't they just train the astronauts to not suffer from this type of
> nausea as much? Or at least have it impact their functionality less.
> Being able to launch with slightly less fuel requried seems quite a
> strong goal to me.

Not really.  It actually comes from the cerebellum and is pretty much a 
reflex.  Your eyes and inner ear disagree, and ever since we were 
dinosaurs, that could only mean one thing "Oh! crap, I've been 
poisoned!" and the reflex is to evacuate the toxin, by sweating and/or 
vomitting.

They teach astronauts to try to compensate for it, but it's not always 
easy, and it used to be easier just to screen them before sending them 
to outer space.  There's one (whose name escapes me at the moment) who 
had to have one of his ear nerves completely severed, making him deaf on 
that side at the same time, to resolve the issue.


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>> Can't they just train the astronauts to not suffer from this type of
>> nausea as much? Or at least have it impact their functionality less.
>> Being able to launch with slightly less fuel requried seems quite a
>> strong goal to me.
>
> Not really.  It actually comes from the cerebellum and is pretty much a
> reflex.  Your eyes and inner ear disagree, and ever since we were
> dinosaurs, that could only mean one thing "Oh! crap, I've been
> poisoned!" and the reflex is to evacuate the toxin, by sweating and/or
> vomitting.

Didn't they try various things like projecting an image onto the inner 
walls that was in sync with the actual movement. Saying that, some 
people still feel ill with the VR kit, and that's only just their head 
moving! The same inputs seem to affect different people by vastly 
different amounts.

> They teach astronauts to try to compensate for it, but it's not always
> easy, and it used to be easier just to screen them before sending them
> to outer space.  There's one (whose name escapes me at the moment) who
> had to have one of his ear nerves completely severed, making him deaf on
> that side at the same time, to resolve the issue.

Now we're talking. Sorry, we need to save 5 kg of fuel, and we can't 
have you puking each time we turn (although if you could just aim your 
puke along this axis and open the window...) so we have to take your 
inner ear out :-)

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Am 19.01.2016 um 08:43 schrieb scott:

>> They teach astronauts to try to compensate for it, but it's not always
>> easy, and it used to be easier just to screen them before sending them
>> to outer space.  There's one (whose name escapes me at the moment) who
>> had to have one of his ear nerves completely severed, making him deaf on
>> that side at the same time, to resolve the issue.
> 
> Now we're talking. Sorry, we need to save 5 kg of fuel, and we can't
> have you puking each time we turn (although if you could just aim your
> puke along this axis and open the window...) so we have to take your
> inner ear out :-)

I suspect it was more like, "Sorry, we need you to /not/ constantly puke
/all/ the time you'll be in /zero-g/, so..."

Also, I somehow suspect that this is an urban legend, where someone got
the following facts wrong:


- Alan Shepard was diagnosed with Meniere's disease during his training
for the Gemini project.

- Meniere's disease does indeed lead to false sensations of rotating,
which in turn is prone to induce nausea.

- In those days, Meniere's disease was indeed typically treated by
neurectomy, i.e. nerve cutting.

BUT:

- Meniere's disease would induce nausea regardless of g forces or
attitude changes involved. I would even reckon that the human brain
might adapt over time.

- Besides inducing nausea, false sensations of rotating would really
mess up your ability to safely pilot an aircraft (and, by extension, at
least from the reasoning of that time, a spacecraft), which would have
been much more of a concern for the Gemini 3 mission. So Alan Shepard
did not undergo treatment to prevent constant puking (because hey, that
was expected to be part of the deal for /anyone/) but to restore his
ability to properly judge changes (or absence thereof) in his
spacecraft's attitude.

- The nerve-cutting procedure to manage Meniere's disease would
apparently only involve the portion of the ear nerve responsible for
relaying orientation and acceleration information, while leaving hearing
intact.

- Meniere's disease does involve impaired hearing anyway.

- Ultimately, Alan Shepard did /not/ have any of his ear nerves cut, and
instead underwent a brand new and entirely different procedure, to be
fitted with a so-called endolymphatic shunt to drain excess fluid from
his inner ear.

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>>> Can't they just train the astronauts to not suffer from this type of
>>> nausea as much? Or at least have it impact their functionality less.
>>> Being able to launch with slightly less fuel requried seems quite a
>>> strong goal to me.
>>
>> Not really.  It actually comes from the cerebellum and is pretty much a
>> reflex.  Your eyes and inner ear disagree, and ever since we were
>> dinosaurs, that could only mean one thing "Oh! crap, I've been
>> poisoned!" and the reflex is to evacuate the toxin, by sweating and/or
>> vomitting.
>
> Didn't they try various things like projecting an image onto the inner
> walls that was in sync with the actual movement. Saying that, some
> people still feel ill with the VR kit, and that's only just their head
> moving! The same inputs seem to affect different people by vastly
> different amounts.
>

Possible.  however, our inner ear has been used to gravity for millions 
of years.  it's not always obvious what it feels in micro-gravity,  and 
sometimes, both ears apparently feel different, as my ex-girlfriend told 
me after flying on the "vomit-comet" once.  so you can't really project 
something diffferent for each astronaut, even less for each eye of the 
same astronaut.

>> They teach astronauts to try to compensate for it, but it's not always
>> easy, and it used to be easier just to screen them before sending them
>> to outer space.  There's one (whose name escapes me at the moment) who
>> had to have one of his ear nerves completely severed, making him deaf on
>> that side at the same time, to resolve the issue.
>
> Now we're talking. Sorry, we need to save 5 kg of fuel, and we can't
> have you puking each time we turn (although if you could just aim your
> puke along this axis and open the window...) so we have to take your
> inner ear out :-)
>
We'd also save space and weight if we simply cut your legs off.  You 
don't need them any way, while you're up there.

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> Am 19.01.2016 um 08:43 schrieb scott:
>
>>> They teach astronauts to try to compensate for it, but it's not always
>>> easy, and it used to be easier just to screen them before sending them
>>> to outer space.  There's one (whose name escapes me at the moment) who
>>> had to have one of his ear nerves completely severed, making him deaf on
>>> that side at the same time, to resolve the issue.
>>
>> Now we're talking. Sorry, we need to save 5 kg of fuel, and we can't
>> have you puking each time we turn (although if you could just aim your
>> puke along this axis and open the window...) so we have to take your
>> inner ear out :-)
>
> I suspect it was more like, "Sorry, we need you to /not/ constantly puke
> /all/ the time you'll be in /zero-g/, so..."
>
> Also, I somehow suspect that this is an urban legend, where someone got
> the following facts wrong:
>
>
> - Alan Shepard was diagnosed with Meniere's disease during his training
> for the Gemini project.
>
> - Meniere's disease does indeed lead to false sensations of rotating,
> which in turn is prone to induce nausea.
>
> - In those days, Meniere's disease was indeed typically treated by
> neurectomy, i.e. nerve cutting.
>

IT's still part of the protocol, but not the first step.


> BUT:
>
> - Meniere's disease would induce nausea regardless of g forces or
> attitude changes involved. I would even reckon that the human brain
> might adapt over time.
>
> - Besides inducing nausea, false sensations of rotating would really
> mess up your ability to safely pilot an aircraft (and, by extension, at
> least from the reasoning of that time, a spacecraft), which would have
> been much more of a concern for the Gemini 3 mission.

When my wife gets her vertigo attacks, she had difficulty piloting her 
bed!  She definitely wouldn't be able to pilot a spaceship.

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