Quote: (09-02-2012 01:01 AM)23Billion Wrote:
Going through Van Allen Radiation belt is suicidal for human beings, or any living thing for that matter. Sputnik was a sphere with a radio in it with a few antennas. They didn't care if the radiation fried it.
Bro the only example I can think of is the one my prof gave me. Its like cleaning uranium/plutonium rods inside heavy water tanks in the nuclear plants. He told me that around 8 years ago those dudes used to get paid $200 - $300 an hour to do just that, don't know about now. But the level of danger posed to living tissue is unbelievable. Now multiply that level of danger by one hundred million and stand inside the tank for one minute in the presence of gamma rays. It is so dangerous that it is unbelievable. There is no known material that can stop the gamma rays, they go through everything and anything. Even through concrete/steel and can cause some serious damage to the living tissue. We just did not have the technology to have the astronauts pass through the radiation safely. The amount of time they spent in space going to the moon, landing there, and hanging out like that would have fried them at cellular level!!
Quote: (09-01-2012 05:07 PM)Icarus Wrote:
Quote: (09-01-2012 04:18 PM)23Billion Wrote:
I don't think they had the technology to go through the Van Allen Radiation belts at that time.
The Sputnik 3 went through the Van Allen Radiation Belt and stayed there, while it orbited the Earth some thousands of times. That was in 1958, over 10 years before the Apollo 11.
Staying in the VARB would be hazardous for humans, but if your travel through the VARB lasts only a few hours, what is the problem? You get irradiated heavily, but you also get irradiated heavily (though less heavily, of course) every time you take a transoceanic flight.
Gamma rays are high energy and can be highly devastating when exposed unshielded in proximity , but not too high in penetration but higher than beta and alpha, gamma rays when going through matter, will be absorbed and reemitted by electrons, thus lose energy and have lower frequencies after the electrons become excited , causing them to lose energy every time they interact with matter. Yes satellite with sensitive parts needs to be shielded.
In fact lower frequency/energy EM waves will have higher penetration, that is why radio waves can travel so far. Lead and high density materials can readily stop gamma rays and alpha particles, even high penetration neutrons when sufficiently thick. In fact any materials sufficient thickness will stop gamma rays.
http://en.wikipedia.org/wiki/Radiation_protection
quote:"
This means when added thicknesses are used, the shielding multiplies. For example, a practical shield in a fallout shelter is ten halving-thicknesses of packed dirt, which is 90 cm (3 ft) of dirt. This reduces gamma rays to 1/1,024 of their original intensity (1/2 multiplied by itself ten times). Halving thicknesses of some materials, that reduce gamma ray intensity by 50% (1/2) include[3]:
Material
Halving Thickness, inches , Halv. thick., cm Density, g/cm³ Halving Mass, g/cm²
lead 0.4 1.0 11.3 12
steel 0.99 2.5 7.86 20
concrete 2.4 6.1 3.33 20
packed soil 3.6 9.1 1.99 18
water 7.2 18 1.00 18
lumber or other wood 11 29 0.56 16
air 6000 15000 0.0012 18
Column Halving Mass in the chart above indicates mass of material, required to cut radiation by 50%, in grams per square centimetre of protected area.