NASASpaceFlight.com Forum

General Discussion => Advanced Concepts => Topic started by: JohnFornaro on 10/06/2009 01:26 PM

Title: Benefits of Centrifuge for AG and Radiation
Post by: JohnFornaro on 10/06/2009 01:26 PM
Over on the Symposium discussion on Augustine thread, there's some talk about the centrifuge that was planned for the ISS but not included.  The ISS could only handle a small one structurally, suitable for labrats or hamsters; perhaps some agricultural experiments.

There is also a need to study long term effects of radiation on humans, as well as the expected benefits of AG for a long trip to Mars.  Of course, the big assumption is continuing with HSF, so:

There's a couple of issues that come to my mind.  Should there be a "special satellite or Bigelow spacestation" placed in orbit beyond the Van Allen belts?  Where, Emily-1? What would be the benefits of working at LEO?  Should there be a smaller device attached to the ISS?  Will the data from a smaller centrifuge, with smaller animals, be good enough to extrapolate for humans?  Both biological and medical research need to happen, it seems to me.  Can the radiation hazard be modeled accurately in the lab, reducing the need for human space study?  What about solar flares?  What about the mass required?

From what I've read, it seems that these issues are not well understood enough so that further space research is not necessary.  Rephrased with fewer negatives:  We need to study this more.

Any comments?
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: simon-th on 10/06/2009 01:34 PM
1. AG experiments in LEO make sense. The effects of long-term exposure of low-G aren't sufficiently known and can't be studied anywhere except on a smaller planetory body or with AG.

2. The radiation environment in deep-space is known. Data is available. Safe radiation dosage amounts for humans are known as well. There is no need to use humans as guinea pigs BEFORE we have specific technology (active shielding or passive shielding) that mitigates GCR exposure and potential radiation exposure from SPEs to an acceptable level. And once we have that technology (or the sufficiently shielded deep-space hab) it makes more sense to go for a real deep-space mission instead for a long-term EML-1/2 mission.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: randomly on 10/06/2009 02:32 PM
The problem is that you can't simulate GCR very accurately on the ground. GCR is not like any radioactive decay source. All radiation is not created equal and what accurate safe dosage amounts are for GCR are not really known. You may not want to use humans as early guinea pigs, but you need some live biological systems exposed to real GCR to get better information to enable more accurate models and ground simulation.

I think we'll need a lab with rotating crews that is stationed outside the Van Allen belts.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: JohnFornaro on 10/06/2009 02:35 PM
I forgot to add that I knew, and that we know in general about some of the deep space radiation hazards, but that a passive system is largely dependant on mass, and an active system would have a mass/complexity problem.  We still don't have a suitable solution or a specific strategy for the radiation problem.

But I agree that the Flexible Path option would be more versatile than a stationary station in a number of ways.  OTOH, a station at EML-1 could be the beginning of a fuel depot/Mars vehicle assembly setup.  Some of the inspace assembly problems have been tentatively solved at ISS.  I don't know about cyro fuel transfer, howeve.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: A_M_Swallow on 10/06/2009 06:04 PM
For a radiation experiment I would imagine 5 sets of animals.

Set 1 - the control group on Earth.  Feed the same food and water as the other animals.

Set 2 - in a rotating centrifuge with just the spacestation's hull as protection.

Set 3 - in a similar rotating centrifuge with extra shielding on the rim and sides.  Possibly a repeat of the spacestation's hull, giving double thickness.

Set 4 - in a rotating centrifuge triple thickness shielding or rival method.

Set 5 - same as Set 2 except the centrifuge is still.  This shows the effect of microgravity.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: Robotbeat on 10/06/2009 06:33 PM
You know, water is paramagnetic and a strong magnetic field will shield you from basically all GCRs, so you can kill two birds with one stone by using a very large magnet (100 T?) and mounting it on the ceiling of a spacecraft, providing both artificial gravity and radiation shielding.

Of course, this is at least a few decades out, barring some great leap in superconductors...
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: stockman on 10/06/2009 06:34 PM
You know, water is paramagnetic and a strong magnetic field will shield you from basically all GCRs, so you can kill two birds with one stone by using a very large magnet (100 T?) and mounting it on the ceiling of a spacecraft, providing both artificial gravity and radiation shielding.

Of course, this is at least a few decades out, barring some great leap in superconductors...

what??? I was unaware that magnetism was equivalent to gravity????  I think you are confusing the two forces....
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: Robotbeat on 10/06/2009 06:36 PM
You know, water is paramagnetic and a strong magnetic field will shield you from basically all GCRs, so you can kill two birds with one stone by using a very large magnet (100 T?) and mounting it on the ceiling of a spacecraft, providing both artificial gravity and radiation shielding.

Of course, this is at least a few decades out, barring some great leap in superconductors...

what??? I was unaware that magnetism was equivalent to gravity????  I think you are confusing the two forces....

It's not at all equivalent, but since mammals are mostly water, it works out that way:
http://www.livescience.com/animals/090909-mouse-levitation.html

Quote
Scientists have now levitated mice using magnetic fields.

Other researchers have made live frogs and grasshoppers float in mid-air before, but such research with mice, being closer biologically to humans, could help in studies to counteract bone loss due to reduced gravity over long spans of time, as might be expected in deep space missions or on the surfaces of other planets.
...

(just put it on the other side, and you have artificial gravity when you're in space, right?)
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: A_M_Swallow on 10/06/2009 07:20 PM
You know, water is paramagnetic and a strong magnetic field will shield you from basically all GCRs, so you can kill two birds with one stone by using a very large magnet (100 T?) and mounting it on the ceiling of a spacecraft, providing both artificial gravity and radiation shielding.

Of course, this is at least a few decades out, barring some great leap in superconductors...

Just make sure that strong magnetic fields do not some weird effect on the human body.  Possibly by messing up a chemical reaction.  This can be tested on Earth.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: AlexInOklahoma on 10/06/2009 08:51 PM
Plus, many, many folks have tiny specks of iron/semi-ferrous matter somewhere in their body from some point in life (I've been MRI-tech, so done plenty of 'screening')  Its the rare person that has had zero exposure to anything that might be torqued/pulled in such a huge field.  Forget about any type of medically-advanced 'implants' if you want to go anywhere near such a thing (workers included) 

I'm really curious how such fields would affect ferrous-based processes in an organism long-term (like hemoglobin maybe?)

Alex
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: Robotbeat on 10/06/2009 08:58 PM
Plus, many, many folks have tiny specks of iron/semi-ferrous matter somewhere in their body from some point in life (I've been MRI-tech, so done plenty of 'screening')  Its the rare person that has had zero exposure to anything that might be torqued/pulled in such a huge field.  Forget about any type of medically-advanced 'implants' if you want to go anywhere near such a thing (workers included) 

I'm really curious how such fields would affect ferrous-based processes in an organism long-term (like hemoglobin maybe?)

Alex

Yeah, obviously it'd be a pretty dangerous field to work with, but, as you say, we already have experience in such fields, like in MRIs. Apparently, no ill effects have been found when exposing rats to very large magnetic fields for a long time (it's mentioned in the article I linked to).
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: AlexInOklahoma on 10/06/2009 10:14 PM
"strong non-levitating fields" does not really equate to what you were talking about (strong *levitating* fields, right?)   Fields that strong (~100T give or take ??) should make things VERY interesting when of any size to exist within (dewar is how big?!), and it will be a tough 'field' to work in, but I do think it bears looking at, of course.  And 'adverse effects' were not defined...speaking of just vertigo or being scared?  Or down to the cellular/molecular level?   I did not see that mentioned in that article...  the word 'ill' not used.  And I am not trying to be trite, I promise  :)

Alex
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: Robotbeat on 10/06/2009 10:27 PM
"strong non-levitating fields" does not really equate to what you were talking about (strong *levitating* fields, right?)   Fields that strong (~100T give or take ??) should make things VERY interesting when of any size to exist within (dewar is how big?!), and it will be a tough 'field' to work in, but I do think it bears looking at, of course.  And 'adverse effects' were not defined...speaking of just vertigo or being scared?  Or down to the cellular/molecular level?   I did not see that mentioned in that article...  the word 'ill' not used.  And I am not trying to be trite, I promise  :)

Alex

You are absolutely correct. We'd need to test this out before we use this as the basis of any sort of artificial gravity for the crew!

However, it was an interesting article and a very different approach to solving this problem (something akin to science fiction, which has gravity on virtually all spaceships because it's cheaper to film that way ;) ).
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: JohnFornaro on 10/07/2009 01:15 PM
Levitating mice.  Wow.  It's gotta feel wierd.  And what about your hemoglobin?  Iron reacts well to magnetic fields.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: 8900 on 10/07/2009 01:50 PM
if you want a centrifuge for human, it will be something like the 2001: A Space Odyssey type...whole space station rotates
but that's nearly impossible...even if you can build such a large structure in space, imagine how can you dock your Soyuz/Shuttle at a rotating space station with a rotating PMA[assuming your docking port is at the axis of rotation]?
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: Nomadd on 10/07/2009 02:05 PM
if you want a centrifuge for human, it will be something like the 2001: A Space Odyssey type...whole space station rotates
but that's nearly impossible...even if you can build such a large structure in space, imagine how can you dock your Soyuz/Shuttle at a rotating space station with a rotating PMA[assuming your docking port is at the axis of rotation]?

 Why is it nearly impossible to rotate the docking spacecraft to match the station?
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: AlexInOklahoma on 10/07/2009 02:38 PM
Levitating mice.  Wow.  It's gotta feel wierd.  And what about your hemoglobin?  Iron reacts well to magnetic fields.

That is kinda what I was getting at as well.  In an extreme example (non-realistic, of course), reminds me of one of those X-men movies (iirr) where one of the bad guys pulls the 'iron out of a good-guy's body to use for some nefarious reason.  And many other metals, if not most of 'em, are affected, though the levels of torque/pull vary widely.  I remember once letting a 'student' carry an aluminum step-ladder into the MRI scan room once and the kiddo was shocked when she felt the ladder trying to align itself - "But its only aluminum!"  :-)  Sure could be fun some days playing around with those less familiar, and fear is healthy.  I am SO glad I never had to kill the field (vent the coolant) - would've been a bad day ;)

I do hope that research with super-strong fields -v- physiology effects continues.  I am not getting my hopes up though with  metals being so prevalent in construction and usage of 'habitations' to get off this planet long-term...

Alex
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: randomly on 10/07/2009 04:01 PM
if you want a centrifuge for human, it will be something like the 2001: A Space Odyssey type...whole space station rotates
You don't rotate the whole station. You only need a centrifuge section for humans rotating inside a pressure hull. There are no rotating pressure joints and the rest of the station is stationary. Not all of the habitable portions of the station need to rotate.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: Jorge on 10/07/2009 05:09 PM
if you want a centrifuge for human, it will be something like the 2001: A Space Odyssey type...whole space station rotates
but that's nearly impossible...even if you can build such a large structure in space, imagine how can you dock your Soyuz/Shuttle at a rotating space station with a rotating PMA[assuming your docking port is at the axis of rotation]?

 Why is it nearly impossible to rotate the docking spacecraft to match the station?

Can't say that it would be impossible for vehicles in general but it would be for the shuttle.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: mmeijeri on 10/07/2009 05:12 PM
Why is it nearly impossible to rotate the docking spacecraft to match the station?

Heheh, anyone here play Elite in the eighties? It was very difficult to dock without a docking computer. And the accompanying music was great. :)
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: A_M_Swallow on 10/07/2009 07:51 PM
if you want a centrifuge for human, it will be something like the 2001: A Space Odyssey type...whole space station rotates
but that's nearly impossible...even if you can build such a large structure in space, imagine how can you dock your Soyuz/Shuttle at a rotating space station with a rotating PMA[assuming your docking port is at the axis of rotation]?

Basically put the docking bay on a separate module at the centre of the circle.  Rotate in the opposite direction from the rest of the spacestation so it appears still.  After docking and fastening the space ship to the station use an ordinary electric motor to rotate the core until everything is rotating in the same direction at the same revolutions per minute.  Reverse on departure.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: A_M_Swallow on 10/07/2009 07:59 PM
"strong non-levitating fields" does not really equate to what you were talking about (strong *levitating* fields, right?)   Fields that strong (~100T give or take ??) should make things VERY interesting when of any size to exist within (dewar is how big?!), and it will be a tough 'field' to work in, but I do think it bears looking at, of course.  And 'adverse effects' were not defined...speaking of just vertigo or being scared?  Or down to the cellular/molecular level?   I did not see that mentioned in that article...  the word 'ill' not used.  And I am not trying to be trite, I promise  :)

Alex

This equipment could also be used to test the effects of low gravity.  Mars gravity is 3.69 m/s2 and lunar gravity is 1.62 m/s2.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: Hop_David on 10/07/2009 10:25 PM
if you want a centrifuge for human, it will be something like the 2001: A Space Odyssey type...whole space station rotates

I believe the old Stanford Tori were based on the assumptions that 1 rpm was max angular velocity humans could be comfortable with and that we needed 1 G to stay healthy.

Both those assumptions are questionable.

I believe the first rotating habs for humans will be much smaller than the 2001 space station.
Title: Re: Benefits of Centrifuge for AG and Radiation
Post by: joema on 10/28/2009 09:34 PM
...Why is it nearly impossible to rotate the docking spacecraft to match the station?

It's not impossible, in fact this was planned as a possible experiment for Apollo on Skylab B (which unfortunately never flew).

The idea was to rotate the entire Skylab/Apollo assembly at 4 rpm to produce roughly lunar gravity, about 0.18 g. Skylab wasn't designed to spin, but structural and control analysis indicated it might sustain 4 rpm for a limited period for experimental purposes.

http://en.wikipedia.org/wiki/Skylab_B
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790072679_1979072679.pdf

You obviously can only rotate a vehicle with characteristics suitable for this, but considering the cost and development time of a large space station, the launch vehicle would be designed for compatibility.

The current shuttle was designed to service a modular zero-G space station. If a future larger rotating space station was designed, the commensurate future service vehicle would be designed to service that.

The movie 2001 showed the concept, with a large wheel-type space station rotating in sync with a shuttle. Note the entire station rotated -- there was no counter-spun stationary hub.

Re human sensitivity to Coriolis dizziness, this varies widely. Some studies indicate selected humans could adapt to 7.5 or even 10 rpm:

http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=11020210&dopt=AbstractPlus