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The Great Unknowns of Space Radiation

Posted by: Chamberland - Tue Jun 13, 2006 1:39 pm
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The Great Unknowns of Space Radiation 
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Post    Posted on: Wed Jun 21, 2006 7:33 pm
WannabeSpaceCadet wrote:
So we ended up with a winged missile that can be refurbished & reused at great expense.
The main refurbishment expense is the tiles and engines. In a one use vehicle both those expenses are avoided.

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Nobody is trying to build a spaceSHIP, because weight is seen as the key design factor. Low weight means low margins, low reliability, high complexity & high cost. Not condusive to re-useability
Well there is nothing light weight about the Shuttle. It weighs almost as much as a Saturn V but has a fraction of the payload. And IMO most of the weight and cost penalty is due to trying TO make it like a ship, with wings to land on a runway instead of a parachute to drop it in the ocean and those fragile tiles instead of an ablative heat shield that gets used up on reentry.


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Post    Posted on: Thu Jun 22, 2006 2:36 am
Hi Ekke,
All this discussion regarding sending living creatures into space to test the effects or otherwise of radiation is all just a lot of space flot. We have all the instrumentation necessary to tell us what's out there that might or might not affect our sort of life, we don't need to go to the effort of providing life support habitats in addition.
As I said before, just send the instruments out there and then send the humans, stop procrastinating.
And by the way, just because something hasn't yet been born into a living creature does not condone or excuse the act of sending into a potentially harmful environment the eggs from which the creature will develop.

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Post    Posted on: Thu Jun 22, 2006 4:04 am
Beancounter, humans are omnivores, it's our natural state.

You're not anti-nature, are you? :twisted:


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Post    Posted on: Thu Jun 22, 2006 4:09 am
There's no such thing as a natural state for humans anymore. The human species decides what state it wishes to inhabit. It operates from choice far more so than other species often to it's own detriment and some would say future survival.

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Post    Posted on: Thu Jun 22, 2006 4:26 am
campbelp2002 wrote:
Quote:
Nobody is trying to build a spaceSHIP, because weight is seen as the key design factor. Low weight means low margins, low reliability, high complexity & high cost. Not condusive to re-useability
Well there is nothing light weight about the Shuttle. It weighs almost as much as a Saturn V but has a fraction of the payload. And IMO most of the weight and cost penalty is due to trying TO make it like a ship, with wings to land on a runway instead of a parachute to drop it in the ocean and those fragile tiles instead of an ablative heat shield that gets used up on reentry.

The shuttle in total is heavy, but the individual parts are all light weight, complex & expensive.

The wings and tiles are part of an attempt to make it like an airplane, not a ship, when it should be neither. It should be a 'landing craft', just enough to get from the ground to a real ship in orbit, and back again.

A real ship is not fragile. A real ship is robust, reliable, and designed for years of operation in its designated environment, with minimal maintenance by the crew. It also provides that crew with comfortable protection from the hazards of that environment.

You can cross the Atlantic in a row-boat or a balsa raft, but I'd rather take the Queen Mary. On the other hand, I wouldn't expect her to be run aground so I can get on or off.


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Post    Posted on: Thu Jun 22, 2006 7:00 am
Hi there. With respect to the Shuttle, aren't you guys basically arguing for the same cause? From what I've seen, the shuttle is comprised of light and heavy complex, new and old equipment, and trys to be all things to all parties ie. a compromise.

I used to think that the shuttle idea of a rocket assisted plane into orbit and return to land was a great idea but not now as I am more aware of the shortcomings. Until we develop better technology then the specialised route would appear to be the most efficient and effective.

The other comment I'd like to make is that I now believe that we need to be able to get larger payloads into space and not just LEO. 20mT seemed like a lot at one stage but if we're really serious about doing exploration and settlements, etc, then we need much larger capacity - I'd shoot for nothing less than 100mT minimum. We need to be able to send things up mainly assembled unless we can significantly improve the flexibility and effectiveness of our spacesuits. The current ones don't seem to allow very much in the way of maneuvrability and the 6hr space walks don't seem to achieve very much when you get down to it.

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Post    Posted on: Thu Jun 22, 2006 7:10 am
Hello, beancounter,

you are right regarding to find out what's out there regarding radiation and particles - but their long-term impacts on beings, living organisms and humans isn't and can't be explored by that.

The reactions of organisms to their environments aren't known sufficiently and satisfyingly even here on Earth. Please think about the extremophiles which have been detected only a few years ago while before their detection scientists were majorly if not in general were convinced that there can't be no life where the extremophiles live.

Rgearding reusability one comment is to be made to this here off-topic discussion: The refurbishment expenses for the Shuttle are no valid argument against reuse or pro one use vehicle - they only are an argument aginst the Shuttle as reusable vehicle. Another reusable vehicle might not require that refurbishment expenses.



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Post    Posted on: Thu Jun 22, 2006 2:08 pm
WannabeSpaceCadet wrote:
The wings and tiles are part of an attempt to make it like an airplane, not a ship, when it should be neither. It should be a 'landing craft', just enough to get from the ground to a real ship in orbit, and back again.
OK, your meaning if ship is a vehicle that never lands, like the starship Enterprise (although the starship Voyager did land in at least one episode I saw).
Anyway, this whole discussion is off topic for this thread.


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Post    Posted on: Fri Jun 23, 2006 12:52 am
Hi Ekke,
Yeah my argument is about sending humans who are aware that the space exploration business is risky (just like climbing Mt Everest) but not sending other species who don't have the ability to choose. I don't believe the human race should be experimenting on ANY living creatures simply for our gain. My view is that the Earth and all it contains was not created simply for the human race to use how we want to. I believe that's the height of arrogance. With our ability to think and choose I believe we should be taking the position of gardians not despots.
Anyway BOT. We still aren't going to really know until we (humans) go there and try it out and take the risk.

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Post    Posted on: Fri Jun 23, 2006 4:32 am
campbelp2002 wrote:
WannabeSpaceCadet wrote:
The wings and tiles are part of an attempt to make it like an airplane, not a ship, when it should be neither. It should be a 'landing craft', just enough to get from the ground to a real ship in orbit, and back again.
OK, your meaning if ship is a vehicle that never lands, like the starship Enterprise (although the starship Voyager did land in at least one episode I saw).
Anyway, this whole discussion is off topic for this thread.


That is what I have in mind, and it relates to this topic because a large ship, designed to stay in space, can have more than adequate radiation protection for its crew. A small vehicle like the CEV will not, so the exact nature of the radiation environment becomes critical.


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Post    Posted on: Fri Jun 23, 2006 7:36 pm
WannabeSpaceCadet wrote:
... a large ship, designed to stay in space, can have more than adequate radiation protection for its crew.
How good is adequate? To be as good as the surface of the Earth would require a magnetic field plus 33 feet of water surrounding the crew. The magnetic field deflects charged particles and the 33 feet of water absorbs neutrons and high energy photons like gamma rays.


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Post    Posted on: Fri Jun 23, 2006 10:43 pm
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Last edited by whonos on Thu Jun 07, 2007 7:12 pm, edited 1 time in total.



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Post    Posted on: Sat Jun 24, 2006 1:14 am
These are exactly the same arguments the so called experts have. You and I are both quoting from different experts. This is why we need a shakedown flight of the actual vehicle with the actual shielding with an actual crew for the actual time outside the Earth's magnetosphere that a round trip to Mars would require, so we can all stop arguing and just know.


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Post    Posted on: Sat Jun 24, 2006 1:22 am
I might point out that just the radiation shielding on this sucker is way past the launch capacity of the CaLV, much less any existing vehicle. Superconductors require prodigious amounts of power and cryogenics (which adds even more to the power draw). Tungsten is ridiculously expensive, and lead is also heavy as all hell. LH2 is a better shielding material per unit mass, anyway, AFAIK. We're getting a bit ahead of ourselves, here: let's find a way to get all this stuff up there before we go laying keels.

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Post    Posted on: Sat Jun 24, 2006 6:27 am
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Last edited by whonos on Thu Jun 07, 2007 7:12 pm, edited 1 time in total.



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