Spaceship like "Discovery One" from 2001 Space Odyssey

[Pawelk198604]

I knew that warp capable space craft like this in Star Trek are impossible with make me sad:( But i wonder does we will have someday spacecrafts like this one in 2001 A Space Odyssey.

[sojourner]

NASA designs the Discovery II.

[NeoMorph]

You mean like this?

http://kerbalspaceprogram.com/discovery-2001/

[Karriz]

The centrifuge in it is too small, I've read that in reality you'd need a ring that is hundreds of meters diameter.

Other than that, why not? It uses some sort of plasma rockets which should be possible in a few decades. Ships like this are pretty much necessary if we ever intend to go to other planets.

[Canopus]

The centrifuge in it is too small, I've read that in reality you'd need a ring that is hundreds of meters diameter.

Other than that, why not? It uses some sort of plasma rockets which should be possible in a few decades. Ships like this are pretty much necessary if we ever intend to go to other planets.

not really hundreds of meters

[ecat]

The centrifuge in it is too small, I've read that in reality you'd need a ring that is hundreds of meters diameter.

Other than that, why not? It uses some sort of plasma rockets which should be possible in a few decades. Ships like this are pretty much necessary if we ever intend to go to other planets.

not really hundreds of meters

Well, split the difference, a couple of hundred maybe ?

To reduce Coriolis forces to livable levels, a rate of spin of 2 rpm or less would be needed. To produce 1g, the radius of rotation would have to be 224 m (735 ft) or greater, which would make for a very large spaceship.

http://en.wikipedia.org/wiki/Artificial_gravity

[Canopus]

Well, split the difference, a couple of hundred maybe ?

http://en.wikipedia.org/wiki/Artificial_gravity

read what it says.

"to produce 1g" then it would have to be that big

[Nuke]

no rule says you cant make do with 0.5gs or even less. if your destination was mars, you would probibly want to match mars gravity, so 0.376gs would be what you need. a larger ring on the other hand would be more versatile though, as you could acclimate astronauts to their target gravity during transit, so on the return trip from a mars mission, your astronauts are re-adjusted to earth gravity before they get there.

if i did the math right you need about an 84.1m centrifuge to get mars gravity at 2 rpm.

Edited August 7, 2013 by Nuke

[ecat]

read what it says.

"to produce 1g" then it would have to be that big

no rule says you cant make do with 0.5gs or even less. if your destination was mars, you would probibly want to match mars gravity, so 0.376gs would be what you need. a larger ring on the other hand would be more versatile though, as you could acclimate astronauts to their target gravity during transit, so on the return trip from a mars mission, your astronauts are re-adjusted to earth gravity before they get there.

if i did the math right you need about an 84.1m centrifuge to get mars gravity at 2 rpm.

It does indeed say 1g and there is indeed no rule against a smaller structure. The big questions are:

What is the scientifically proven minimum g required to negate all harmful effects?

At what point do the the Coriolis forces become a problem?

[dharak1]

It does indeed say 1g and there is indeed no rule against a smaller structure. The big questions are:

What is the scientifically proven minimum g required to negate all harmful effects?

At what point do the the Coriolis forces become a problem?

If we send people to other planets on these then it would be logical to save on cost and training to have the size match for the gravity of the destination. If the destination is safe low G then the wheel works. I would think the problem with the Coriolis effect is when you flush the toilet it makes a hurricane . On a more serious note it might have something to do with bodily fluids like blood getting messed with.

[Kerbface]

Well, split the difference, a couple of hundred maybe ?

http://en.wikipedia.org/wiki/Artificial_gravity

Well, there is a lot of disagreement on the exact maximum RPM that could be liveable (though full 1G is certainly not necessary to minimise the effects, might be needed if you wanted permanent habitation with the ability for future generations to get back to Earth without trouble), there haven't been many tests (and all on Earth so the sideways (to the person in the centrifuge) force of gravity is a factor) but usually the figure I've heard for reasonable comfort for most, or at least after a time to get used to it, is between 2 and 4 RPM max. But I have heard of some cases where people were able to cope with higher. But on a pedantic note, how is the split difference between "hundreds of metres" and "not really hundreds of metres" "a couple of hundred metres"?

[ecat]

Well, there is a lot of disagreement on the exact maximum RPM that could be liveable (though full 1G is certainly not necessary to minimise the effects, might be needed if you wanted permanent habitation with the ability for future generations to get back to Earth without trouble), there haven't been many tests (and all on Earth so the sideways (to the person in the centrifuge) force of gravity is a factor) but usually the figure I've heard for reasonable comfort for most, or at least after a time to get used to it, is between 2 and 4 RPM max. But I have heard of some cases where people were able to cope with higher.

This is exactly the point I went on to try and get people to think about. We don't know. 0.1G or 0.5G, we have no idea of the mid to long term effects. Twelve months, twenty four months, again we have no idea. The safe answer is close to 1G, any other answer lies somewhere between possible and public relations nightmare.

But on a pedantic note, how is the split difference between "hundreds of metres" and "not really hundreds of metres" "a couple of hundred metres"?

Feel free to pick any reason from the following:

1) Attempt at diplomacy.

2) The Terry Pratchett principle of counting: One, two, three, many.

3) Standard English: One, a couple, a few (more than two but less than a lot), a lot.

[satcharna]

Discovery One is beautiful for what it is, a rather realistic spacecraft. While it is true that the rings would be too small by far (one of them is actually not there at all), and the pod bay would by necessity not have a centrifuge, they're rather small problems compared to what most spacecraft in films are like. Discovery One doesn't run its engines on full thrust for the duration of the trip, when it meets an asteroid there is no surprise, the two just drift by each other, and it has radiators to both support life and cool the power supply. Few other spacecraft have had so much thought and scientific influence during the design process.

There's also the fact that it was equipped with tablet computers decades before they became anywhere near commonplace. If only we could have had had joint Soviet-US commercial moon bases as well, life would be good.

[Tommygun]

Here is a calculator for spinning artificial gravity and it might be of some interest, but the values may be subject to some opinion.

It seems to like a radius of 224 meters for a spinning torus.

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

[Nuke]

this is a really good calculator, i get 75m radius @ 2 rpm with green lights all the way down and 1/3g. perfect for a mars hopper.

[sojourner]

Discovery One is beautiful for what it is, a rather realistic spacecraft. While it is true that the rings would be too small by far (one of them is actually not there at all),

Wait, what rings are you talking about?? Discovery in the movie only had one centrifuge for artificial gravity, as seen.

and the pod bay would by necessity not have a centrifuge,

Which is exactly as it was portrayed. If you watch 2001 closely, the podbay is in zero G and there is velcro on the floor to provide traction.(sadly, the Velcro was omitted when the set was recreated for the movie 2010)

[Kerbface]

This is exactly the point I went on to try and get people to think about. We don't know. 0.1G or 0.5G, we have no idea of the mid to long term effects. Twelve months, twenty four months, again we have no idea. The safe answer is close to 1G, any other answer lies somewhere between possible and public relations nightmare.

Less than 1G is just closer to zero G. There is no way partial G could NOT be helpful to astronauts, and it certainly can't have any worse or different effects than zero G (having a too small radius or too high a rotation speed is a different issue). It WOULD minimise the negative effects of zero G, the question is simply how much. But people's bone mass, for example, would surely not degrade below the level required for comfortable standing on the level of gravity they have in the ship.

[satcharna]

Wait, what rings are you talking about?? Discovery in the movie only had one centrifuge for artificial gravity, as seen.Which is exactly as it was portrayed. If you watch 2001 closely, the podbay is in zero G and there is velcro on the floor to provide traction.(sadly, the Velcro was omitted when the set was recreated for the movie 2010)

I was referring to the centrifuge. You would need another centrifuge or reaction wheel spinning in reverse in order to cancel out the rotation, otherwise the whole spacecraft would begin spinning. I was not aware that the pod bay was supposed to have velcro, they did not share the peculiar gait of the stewardess when they used it.

[magnemoe]

This is exactly the point I went on to try and get people to think about. We don't know. 0.1G or 0.5G, we have no idea of the mid to long term effects. Twelve months, twenty four months, again we have no idea. The safe answer is close to 1G, any other answer lies somewhere between possible and public relations nightmare.

We have plenty of experience with weightlessness over time. None with low gravity over long time.

If you use the centrifuge only as an exercise room and not as a living quarter it could be smaller as you would just be in it some hours every day. But it would probably be simpler to do exercise other ways, straps to push you against the floor and an suit who restricted movement should work.

[drakesdoom]

I was referring to the centrifuge. You would need another centrifuge or reaction wheel spinning in reverse in order to cancel out the rotation, otherwise the whole spacecraft would begin spinning. I was not aware that the pod bay was supposed to have velcro, they did not share the peculiar gait of the stewardess when they used it.

That is only if you want a reaction less spin up of the wheel. There could have been reaction wheels built into it around the entrance locks to counter the momentum or they could have used thrusters to counter the spin. If it wont be spun up or down often that could be feasible.

[Nuke]

you only have to match angular momentum, not mass, radius, rpm, etc. so a smaller, less massive disc doing 20000rpm might be able to counteract the 2 rpm of the centrifuge. so a dual centrifuge is not really neccisary, though it certainly is an option.

Edited August 8, 2013 by Nuke

[satcharna]

That is only if you want a reaction less spin up of the wheel. There could have been reaction wheels built into it around the entrance locks to counter the momentum or they could have used thrusters to counter the spin. If it wont be spun up or down often that could be feasible.

You're forgetting the inevitable friction. You'd pretty much be forced to constantly apply force in order to keep the centrifuge spinning, which renders rockets impractical. Secondary reaction wheels were what I had in mind, actually.

I'm just happy they have a centrifuge in the first place, instead of magical gravity generators like most other sci-fi.

[DerekL1963]

You're forgetting the inevitable friction.

With magnetic or gas bearings, there'll be damm little friction - and the mass of Discovery is very large compared to the mass of the centrifuge.

[satcharna]

With magnetic or gas bearings, there'll be damm little friction - and the mass of Discovery is very large compared to the mass of the centrifuge.

The mass of the centrifuge wouldn't be uniform, especially considering that it has people moving around inside of it.

[DerekL1963]

Total mass satcharna.