Artificial gravity?

Hi all, just popped in to this group, as I've heard its a good place
for space questions answers.

My question is this:

You have a rotor 200 meters in diameter, that's rotating at 3 rpm, and
as a result you in a pod or the edge of a ring get to feel 0.5 g
artificial gravity.

In order to feel 1 g or Earth gravity, would the rotor or rin need to
rotate at 6 rpm, or would that cause problems?

Christopher ) writes:
Hi all, just popped in to this group, as I've heard its a good place
for space questions answers.

My question is this:

You have a rotor 200 meters in diameter, that's rotating at 3 rpm, and
as a result you in a pod or the edge of a ring get to feel 0.5 g
artificial gravity.

In order to feel 1 g or Earth gravity, would the rotor or rin need to
rotate at 6 rpm, or would that cause problems?


The apparent gee force varies as the square of the rotation rate (for fixed
radius); so the rotor would have to rotate at about 4.2 rpm. Not sure what
problems you have in mind.

--John Park

Christopher wrote:

Hi all, just popped in to this group, as I've heard its a good place
for space questions answers.

My question is this:

You have a rotor 200 meters in diameter, that's rotating at 3 rpm,
and
as a result you in a pod or the edge of a ring get to feel 0.5 g
artificial gravity.

In order to feel 1 g or Earth gravity, would the rotor or rin need to
rotate at 6 rpm, or would that cause problems?

Hi Chris,
it's basic physics: the centripetal acceleration formula is
acceleration = (omega**2)/r
where omega is the angular velocity in radians per second, and r is the
radius.
Do your own math and speed/radius trade-offs!

If I remember well, when I was young (circa 1955:1960) this idea was
called the von Braun (yes the man behind the Redstone and Saturn and
other such achievements) space station, and was a (big - apparently
much more than the International Space Station) pressurized ring
connected to its hub by a diametral spoke. The hub carried contra-
rotating antennas for communication and connectors for space vehicles
carry man and supplies.
I do not know if it were Sci-Fi or true science, but as far as I know
such an idea was never resurrected after that. I do not ever know if
this is a viable idea or not.

Hoping this helps
Gigi

Christopher:

My question is this:

You have a rotor 200 meters in diameter, that's rotating at 3 rpm, and
as a result you in a pod or the edge of a ring get to feel 0.5 g
artificial gravity.

In order to feel 1 g or Earth gravity, would the rotor or rin need to
rotate at 6 rpm, or would that cause problems?
----
Acceleration = (rotation rate)^2 x r

3 rpm = 3 x (2 x pi) / 60 = 0.314 radians / sec

r = 100 m

Acceleration = 9.869 m/s/s == just over 1 gee (so no need to
increase rotational speed)
----

6 rpm == just over 4 gee (double the rotational speed squared)

----

Agreed, a good place to ask questions.
Also, a number of people here will check my math, just to be sure.

On 28/09/2010 1:15 PM, Christopher wrote:
Hi all, just popped in to this group, as I've heard its a good place
for space questions answers.

My question is this:

You have a rotor 200 meters in diameter, that's rotating at 3 rpm, and
as a result you in a pod or the edge of a ring get to feel 0.5 g
artificial gravity.

In order to feel 1 g or Earth gravity, would the rotor or rin need to
rotate at 6 rpm, or would that cause problems?


It would produce 2g - it's proportional to the square of the rate of
rotation. 4.24 rpm would give 1g.

It's not an exact simulation of gravity because of the coriolis effect,
which can lead to difficulties.

See

http://en.wikipedia.org/wiki/Artific...avity#Rotation

Sylvia.

GianLuigi Piacentini wrote:
it's basic physics: the centripetal acceleration formula is
acceleration = (omega**2)/r
where omega is the angular velocity in radians per second, and r is the
radius.

That equation isn't even dimensionally consistent. What you meant was:

a = omega^2 r

--
Erik Max Francis && && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
Money talks / But love is for real / And you know that
-- Neneh Cherry

Thank you for all the answers.

So you just increase the 200 meter rotor/ring to 4.24 rpm for 1 g
Earth like artificial gravity, never guessed it'd be that simple.

FWIW the basis of the question was I finally got round to watching the
DVD of the BBC sci-fi drama documentary "'Space Odyssey:Yoyage to the
planets', and the 'Pegasus' had a crew habitat that was a 200 meter
rotor rotating at 3 rpm the generate .5 g.

Which apart from the facts only 5 people were in the crew-you need a
lot more ppl, and it was a very very limited Odyssey, with 4 surface
EVA destinations, and one crew member got killed seemed rather
pointless, as if you are on a long interplanetary voyage, you would
want to live in a 1 g Earth environment when you were in the crew
habitat, so your bones don't become weaker under half gravity.

An additional question the 'Pegusus' had was the 'fusion reactor' come
main rocket engine, was located at the far end of the main truss.

Given that like in 2001: A Space Odyssey -in the novel, as well as in
the movie- the 'Discovery, had a fission nuclear power plant, for
power locvated at the fare end of the main truss, how far from the
crew habitat would you have the nuclear reactor? 300 meters, 500
meters, 700 meters?

As you wouldn't want to be right next to the reactor getting you cells
all warm and toasty now would you.

Christopher ) writes:
Thank you for all the answers.

So you just increase the 200 meter rotor/ring to 4.24 rpm for 1 g
Earth like artificial gravity, never guessed it'd be that simple.

Check the arithmetic. I think Anvil* got it right, if the rotor is turning
about its mid-point.

--John Park

On Sep 28, 8:16 pm, Sylvia Else wrote:
On 28/09/2010 1:15 PM, Christopher wrote:

Hi all, just popped in to this group, as I've heard its a good place
for space questions answers.

My question is this:

You have a rotor 200 meters in diameter, that's rotating at 3 rpm, and
as a result you in a pod or the edge of a ring get to feel 0.5 g
artificial gravity.

In order to feel 1 g or Earth gravity, would the rotor or rin need to
rotate at 6 rpm, or would that cause problems?

It would produce 2g - it's proportional to the square of the rate of
rotation. 4.24 rpm would give 1g.

It's not an exact simulation of gravity because of the coriolis effect,
which can lead to difficulties.

See

http://en.wikipedia.org/wiki/Artific...avity#Rotation

Sylvia.

Increasing the radii and reducing the rpm takes care of whatever
coriolis effect.

~ BG

On Sep 27, 11:15 pm, Christopher wrote:
Hi all, just popped in to this group, as I've heard its a good place
for space questions answers.

My question is this:

You have a rotor 200 meters in diameter, that's rotating at 3 rpm, and
as a result you in a pod or the edge of a ring get to feel 0.5 g
artificial gravity.

In order to feel 1 g or Earth gravity, would the rotor or rin need to
rotate at 6 rpm, or would that cause problems?

http://www.artificial-gravity.com/sw...c/SpinCalc.htm