The Briefing Room
General Category => Science, Technology and Knowledge => Space => Topic started by: Scutter on February 01, 2017, 11:44:23 pm
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Need more sources than this...
Space Ping!
@Oceander
@Sanguine
@Cripplecreek
@Freya
@EC
@Joe Wooten
@r9etb
@Just_Victor
@montanajoe
@Ghost Bear
@Free Vulcan
@Idaho_Cowboy
@geronl
@Scutter
@Elderberry
@InHeavenThereIsNoBeer
@Rikki Tikki Tavi
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Well, Darn. I'll be old by then.
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Radiation is relatively easy to deal with.
Water is a great shielding material.
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Radiation is relatively easy to deal with.
Water is a great shielding material.
That is why this story kinda smells...
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NASA has known about for at least 10 years—radiation— is more serious than the space agency thought, even though they were warned about it at the time by Frank Cucinotta, the radiation health officer at the Johnson Space Center.
We've known radiation was going to be a problem for far more than ten years.
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Well, Darn. I'll be old by then.
Exactly my thought! Too old to go.
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That is why this story kinda smells...
I think the Bigelow habitats are worth looking at because shielding material can be mixed with the foam inside the walls for a lightweight shielding option.
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(https://img.clipartfest.com/7c05bac5505771a694ef08f1484ad3a9_red-flag-marshal-small-red-flag-clipart_377-546.gif)
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I think the Bigelow habitats are worth looking at because shielding material can be mixed with the foam inside the walls for a lightweight shielding option.
I think so as well..
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Need more sources than this...
Shielding Space Explorers From Cosmic Rays
Expert opinions are split on the most promising strategies for protecting astronauts from the
dangers of cancer-inducing radiation in space.
Eugene N. Parker
18 August 2005
http://engineering.dartmouth.edu/~d76205x/research/Shielding/docs/Parker_05.pdf (http://engineering.dartmouth.edu/~d76205x/research/Shielding/docs/Parker_05.pdf)
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Shielding Space Explorers From Cosmic Rays
Expert opinions are split on the most promising strategies for protecting astronauts from the
dangers of cancer-inducing radiation in space.
Eugene N. Parker
18 August 2005
http://engineering.dartmouth.edu/~d76205x/research/Shielding/docs/Parker_05.pdf (http://engineering.dartmouth.edu/~d76205x/research/Shielding/docs/Parker_05.pdf)
I suggest you watch this:
http://www.youtube.com/watch?v=tcTZvNLL0-w
Listen to Robert Zubrin..
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Earth protects itself with a magnetic field - why cant we do the same to a space vehicle?
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Earth protects itself with a magnetic field - why cant we do the same to a space vehicle?
Cause we are wasting our time on some useless study (I'm talking about the Year in Space study)..
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Earth protects itself with a magnetic field - why cant we do the same to a space vehicle?
Magnetic Shielding
Consider, then, the possibility of generating a magnetic field analogous to Earth’s to protect a spacecraft and its
inhabitants. Because of the small dimensions of a spacecraft compared to a planet, a magnetic field around a
spacecraft must be very intense, of the order of 20 T—400,000 times more intense than the static magnetic field
of Earth.
Recent engineering studies indicate that adequately shielding a modest cabin for the astronauts can be achieved
in this manner, but only if the system is constructed with superconducting wires to carry the electric current
without loss. That scenario requires a system with a total weight of about 9 t—still too heavy to land on Mars
and take off again—with most of that weight in the cryogenic system that maintains the cold, superconducting
wires and in the rigid structure necessary to hold the current-carrying wires in place.
The nature of magnetic fields poses an additional complication. A certain number of particles will leak through
even the most efficient magnetic shield. Once inside, the particles will be confined for a time for the same
reason that they had difficulty getting in. Basic laws of physics tell us that without absorption, the magnetized
space will eventually become filled with particles up to the same intensity as the cosmic rays in the surrounding
space. That means a magnetically shielded spacecraft must also serve as a particle absorber to scavenge the
accumulation of leakage. That is to say, even the best of ships must pump the bilges occasionally.
Some engineers think that advances in technology might eventually make it possible to generate a magnetic
shield with a lighter system, and the spacecraft itself may well provide enough absorbing material to keep the
leaking particles from accumulating in the shield field and exposing the astronauts. But even without these
limiting factors, residing inside such a strong magnetic field may pose a serious health risk.
The biological consequences of long-term exposure to strong, static magnetic fields are inconclusive, but one
reason for concern arises from a single data point that John Marshall mentioned to me many years ago. Marshall
was referring to an informal experiment in which a magnetic field of 0.5 T—only about one fortieth of the
required shielding field—caused electrolysis in the saliva (a lemony taste in the mouth) and scintillations in the
retinas, indicating that any motion in such fields interferes with the normal chemistry of the human body.
Those findings alone suggest that any magnetic shielding system must cancel out most of the magnetic field
over the living space of the astronauts. This field reversal could be accomplished by inducing two electrical
currents around the living quarters to generate a magnetic field with the opposite polarity as the main shielding
dipole (see Figure 1). The downside is that the spacecraft would be weighed down further by the additional steel
it would take to hold those reverse currents in place.
To exactly what degree the shielding field must be weakened, however, is still unknown. Perhaps the human
body can tolerate fields of 0.5 T or more. If so, the engineering challenges would be reduced in other words,
the main shielding field would not have to be cancelled with great precision. More research is vital to determine
what level of effort is truly necessary.
http://engineering.dartmouth.edu/~d76205x/research/Shielding/docs/Parker_05.pdf (http://engineering.dartmouth.edu/~d76205x/research/Shielding/docs/Parker_05.pdf)
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Radiation is relatively easy to deal with.
Water is a great shielding material.
Except that you have to carry a lot of it with you, and you can't really use it for anything else so long as you need the shielding.
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Radiation is relatively easy to deal with.
Water is a great shielding material.
Aside from being ridiculously heavy, you mean....
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Aside from being ridiculously heavy, you mean....
But something you must take anyway.
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But something you must take anyway.
True enough, but the amount needed for shielding is orders of magnitude greater than that needed for drinking, etc, and if you need it for shielding, you can't use it for something else, so water for shielding would be in addition to whatever other water resources you needed for drinking, etc.
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Radiation is relatively easy to deal with.
Water is a great shielding material.
@Cripplecreek
Water is pretty heavy though,and weight is a prime concern.
What about dust? There has to me some forms of dust that are more effective at blocking radiation than others.
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The best way to deal with this is to make sure the trip doesn't last anything close to 4 years.
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The best way to deal with this is to make sure the trip doesn't last anything close to 4 years.
Yup. That's why I always support propulsion and artificial G research as being priorities.
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The article is the reported opinion of one NASA specialist.
Then the article, not the NASA specialist, makes the statement that things will be delayed 20 years and proceeds to fearmonger cosmic rays.
1. No you could not launch enough shielding water in one launch. But the technology exists now to make multiple launches, using simple tankers, to feed a single Mars ship.
2. The biggest concern is high energy gamma radiation, essentially powerful x-rays. Gamma shielding is proportional to the mass of the shielding. A large mass of water, several feet, will do it. Yes, the water used for shielding could be used for other on-board uses, as long as it is recycled back to maintain a sufficient thickness of shielding. Think of it as a reservoir.
3. Alpha radiation is stopped completely by a single sheet of paper, because it is a large particle. An even larger particle, like an iron nucleus, even at near relativistic speeds, is stopped by the metal exterior of the space vehicle.
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The article is the reported opinion of one NASA specialist.
Then the article, not the NASA specialist, makes the statement that things will be delayed 20 years and proceeds to fearmonger cosmic rays.
1. No you could not launch enough shielding water in one launch. But the technology exists now to make multiple launches, using simple tankers, to feed a single Mars ship.
2. The biggest concern is high energy gamma radiation, essentially powerful x-rays. Gamma shielding is proportional to the mass of the shielding. A large mass of water, several feet, will do it. Yes, the water used for shielding could be used for other on-board uses, as long as it is recycled back to maintain a sufficient thickness of shielding. Think of it as a reservoir.
3. Alpha radiation is stopped completely by a single sheet of paper, because it is a large particle. An even larger particle, like an iron nucleus, even at near relativistic speeds, is stopped by the metal exterior of the space vehicle.
As I understand it the hydrogen in the water absorbs radiation and re-emits a much lower energy form.
Its why these guys can stand around extremely radioactive fuel rods in lab coats.
(http://i.imgur.com/D24fqlJ.png)
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Did anyone really expect NASA to perform the first manned trip to Mars? I know I didn't. It's more likely that SpaceX will land private astronauts there long before NASA does.
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Did anyone really expect NASA to perform the first manned trip to Mars? I know I didn't. It's more likely that SpaceX will land private astronauts there long before NASA does.
And why would they go? I mean, Elon loves the publicity of saying so, but ... why would they go there?
And just to be clear: radiation does not distinguish between NASA and private astronauts.
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And why would they go? I mean, Elon loves the publicity of saying so, but ... why would they go there?
And just to be clear: radiation does not distinguish between NASA and private astronauts.
No, radiation doesn't. But willpower seems to.
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No, radiation doesn't. But willpower seems to.
The only thing NASA is lacking is the executive commitment. Perhaps that is going to change.
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The only thing NASA is lacking is the executive commitment. Perhaps that is going to change.
The nature of any political organization is that the commitment only lasts as long as the administration that makes it. And for a big-ticket item like a manned Mars mission, that's not long enough.
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The nature of any political organization is that the commitment only lasts as long as the administration that makes it. And for a big-ticket item like a manned Mars mission, that's not long enough.
Probably true. Maybe if NASA could just get the mission underway before the next administration so that backing out isn't an option.
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The nature of any political organization is that the commitment only lasts as long as the administration that makes it. And for a big-ticket item like a manned Mars mission, that's not long enough.
Whereas a private venture would have to rely on either a reasonable return on investment within a reasonable time; or the undivided attention of uber-rich hobbyists with money to burn.
There are a couple of things to keep in mind.
First, we're really just talking about the word manned. Unmanned Mars missions are quite common these days. So any discussion has to focus on the rationale for sending people, rather than robots.
Second, if we decide to do a manned mission, we have to consider the best "business case" for getting it done.
And to be honest, a large-scale government program is perhaps the better business plan, if only because big money is easier to come by, and ROI is not an issue.
The downside of a government program is that it typically has to address some long-term threat, rather than some nebulous feel-good pabulum about mankind's need to explore. Which is why, for example, the early Space Program was undertaken to address the threat of Russian dominance in space.
The downside of a private program is that the ROI just doesn't seem to be there, and hobbyists generally don't have billions to toss down the rathole.
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Well, Darn. I'll be old by then.
I was thinking the same thing.
Those of us who remember Yuri Gagarin, Sputnik, Alan Shepard, and John Glenn might not be too alert by the time this happens. ^-^
@Idaho_Cowboy
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We've known radiation was going to be a problem for far more than ten years.
Yeah. You and I have discussed this before on other boards. That is one reason we did not go to Mars with manned missions 30 years ago, though the cost trumped everything else.
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Radiation is relatively easy to deal with.
Water is a great shielding material.
Yes it is, BUT, the cost of boosting that water into LEO is huge. You will need a lot of it.
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Yes it is, BUT, the cost of boosting that water into LEO is huge. You will need a lot of it.
Use the water they said they found on the moon. (I know that'd be even more expensive)
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Use the water they said they found on the moon. (I know that'd be even more expensive)
That's why we go back to the moon first. Get the infrastructure built and learn how to survive and thrive on a world a lot closer to home in case the fecal matter hits the rotary air moving device.....