Post by fm on Nov 8, 2009 11:41:18 GMT -4
So was fm a seagull poster?
Oh no... not at all several things:
Busy life and I was looking deeper into this issue.
Someone asked, have I tried Google, etc. Yes I did, and that's how I came to this site in the first place. But in case I didn't "Google" good enough, I went back and did more research. But my hope was to get answers from this forum, from people who obviously have spent more time on this to get the straight dope. But reading the replies, Im just not seeing it. What I'm reading are a lot of assumptions and circular arguments.
Either space is a sea of deadly fatal radiation that makes it impossible with today's technology, or technology from the 20th century to make it to the moon and back, or its not. Why is it hard to get a straight answer backed up with facts?
Now the claim is that NASA lied about actually landing a men to the moon and returning them safely to Earth. And one of the main stumbling blocks was the radiation issue. The only way to catch a liar in a lie to catch them in a contradiction, compare their story to someone else, or pick out what the liar is not revealing or hiding. So, lets see if NASA is lying about space radiation in terms of the feasibility of Apollo.
First:
radiation and humans:
Ionizing radiation includes beta particles, alpha particles, gamma rays, and x-rays; the term excludes radio, microwave, infra-red, and visible radiations.
The biological damage caused by ionizing radiation, including gamma rays and x-rays, is due to high-speed particles traveling through cells and unloading concentrated amounts of energy in unnatural places at random. Each particle creates a very narrow path of disturbance (called a primary "ionization track") as it unloads energy at irregular intervals.
At high radiation doses, many tracks from high-speed electrons pass through every cell-nucleus. How many tracks? At 100 rads from medical x-rays, about 130 primary tracks cross every cell-nucleus based on 30 KeV x-rays on the average, from 90 kV peak. At 100 rads from gamma rays, about 300 tracks cross every cell-nucleus based on ~630 KeV gamma rays from radium-226 or decay of cesium-137 into stable barium-137.
In the mainstream medical literature are quite a number of epidemiological studies showing that even minimal doses of ionizing radiation induce extra cases of cancer. The references are flagged (#) in the list : www.ratical.org/radiation/CNR/NoSafeThresh.html#refs
One roentgen of gamma radiation exposure results in about one rad of absorbed dose, 1 rad of exposure results in 1 rem of dose. Rem: Or, Roentgen Equivalent Man is a unit that relates the dose of any radiation to the biological effect of that dose
So
1–2 Sv (100–200 rem)
Light radiation poisoning, 10% fatality after 30 days (LD 10/30)
to
6–10 Sv (600–1,000 rem)
Acute radiation poisoning, near 100% fatality after 14 days (LD 100/14).
Also important because it gets confusing for me- electron volt:
1.00E+00 eV = 1.00E+03 keV
= 1.00E+06 meV
= 1.00E+09 geV
Ok, so now I think I understand a little bit what is radiation is about when hoaxer's and believers debate this. And what I'm seeing is that it doesn't take much ionized radiation to harm humans.
NASA Astronaut - BFO 3% excess cancer mortality 25 rem/month
NASA Astronaut - BFO 3% excess cancer mortality 50 rem/year
NASA Astronaut - BFO 3% excess cancer mortality 100 to 400 rem/career
According to NASA: Radiation doses on the Apollo mission ranged from a minimum on Apollo 7 of about 0.40 rem to a maximum on Apollo 14 of about 2.85 rem
There are 3 main sources of radiation in space. There is cosmic radiation, Solar Particle Events, and the Van Allen belts
First The Van Allen Belts
The outer belt consists mainly of high energy (0.1–10 MeV)
MeV = 100 million electron volts
Very low energy particles cannot penetrate the skin of a spacecraft, nor even the skin of an astronaut. Very roughly speaking, electrons below about 1 million electron volts (MeV) are unlikely to be dangerous, and protons below 10 MeV are also not sufficiently penetrating to be a concern...
Is this correct?
The outer belt is larger than the inner belt and its particle population *fluctuates widely*. Energetic (radiation) particle fluxes can increase and decrease dramatically as a consequence of geomagnetic storms, which are themselves triggered by magnetic field and plasma disturbances produced by the Sun. The increases are due to storm-related injections and acceleration of particles from the tail of the magnetosphere.
Some of the outer belt electrons can be accelerated to very high energies, and it is these ‘killer electrons’ that can penetrate thick shielding and damage sensitive satellite electronics. This intense radiation environment is also a threat to astronauts.
The number of ‘killer electrons’ can increase by a factor of a thousand at the peak of a magnetic storm and in the following days. Intense solar activity can also push the outer belt much closer to Earth, therefore subjecting lower altitude satellites to a much harsher environment than they were designed for.
The inner Van Allen Belt extends from an altitude of 100–10,000 km above the Earth's surface, and contains high concentrations of energetic protons with energies exceeding 100 MeV and electrons in the range of hundreds of keV, trapped by the strong (relative to the outer belts) magnetic fields in the region.
And of course
Recently a new belt has been found within the inner belt. It contains heavy nuclei (mainly oxygen, but also nitrogen and helium, and very little carbon) with energies below 50 MeV/nuc. The source of these particles are the so called "anomalous cosmic rays" of interstellar origin.
Lead author, Dr Richard Horne of the British Antarctic Survey (BAS) says "Solar storms can increase radiation in the Van Allen belts to levels that pose a threat to spacecraft.
Discovered by Van Allen who said in 1959:
"All manned space flight attempts must steer clear of these two belts of radiation until adequate means of safeguarding the astronauts has been developed"
1. What did he mean by adequate safeguarding?
Does aluminum count?
NASA on Aluminum:
The advantage of plastic-like materials is that they produce far less "secondary radiation" than heavier materials like aluminum or lead. Secondary radiation comes from the shielding material itself. When particles of space radiation smash into atoms within the shield, they trigger tiny nuclear reactions. Those reactions produce a shower of nuclear byproducts -- neutrons and other particles -- that enter the spacecraft. It's a bit like trying to protect yourself from a flying bowling ball by erecting a wall of pins. You avoid the ball but get pelted by pins. "Secondaries" can be worse for astronauts' health than the original space radiation!
2. Did the Apollo missions stay clear of the belts?
What I found: Apollo missions left LEO heading for the moon when radiation belts were 11 degrees South and they were about 28.5 degrees North, thus missing most of the radiation [N. H. Langton, 1969, The Space Environment. page 134]
Is this true?
So by bypassing the VABs does this then confirm the danger of the VABs? Furthermore, NASA States:
The radiation belts are of importance primarily because of the harmful effects of high energy particle radiation for man and electronics:
it degrades satellite components, particularly semiconductor and optical devices
it induces background noise in detectors
it induces errors in digital circuits
it induces electrostatic charge-up in insulators
it is also threat to the astronauts
Who would want to risk equipment and lives going through that?
We also have this curious statement back in 1994:
NASA Chief Dan Goldin interviewed by UK TV journalist Sheena McDonald. He said that mankind cannot venture beyond Earth orbit, 250 miles into space, until they can find a way to overcome the dangers of cosmic radiation.
So who here wants to state that the missions went through the VABs?
If so... what is the dose one might get going though the VABs?
James Van Allen's calculation 10-100rem/hr for a lead-shielded dose from March 1959 Scientific American article.
The 312.5-11,666rem/hr for an unshielded dose comes from E.E. Kovalev's article in the Dec 1983 Aviation Space & Environmental Medicine.
The SAA's 2.5rem/hr figure comes from the same article by Kovalev.
Sorry, but if these figure are correct, the Astronauts could not have gone through the belts in one piece. A dose of minimum 300 rem in an hour?
Does anyone have other figures for the dosages?
NASA:
Astronaut doses incurred from the Van Allen belts
highly depend on the time spent in the high-flux regions of the belt and the state of the fields at the time of exposure. Large temporal variations are observed in the outer zone of the belts in which a dose incurred over a short time period may increase by an order of magnitude or more. The nature of the energy spectrum is such that crew members in a thinly shielded spacecraft can incur very large doses.
For a moderately shielded spacecraft (aprox 5g/cm2 (water or aluminum? Im assuming water because this has to do with traveling to Mars. And nobody I've seen now supports aluminum shielding for that)), such as those contemplated for advanced missions, doses incurred during transit through the trapped belts are not significant compared with the anticipated free-space contributions. However, substantial cumulative exposures in the belts will result for sustained operation in low Earth orbit (LEO) at altitudes greater than approx. 400km. In addition, conceptual multiple-pass trajectories spiraling through the trapped regions may also result in significant doses.
The hull of an Apollo command module rated 7 to 8 g/cm2.
A modern space shuttle has 10 to 11 g/cm2.
The hull of the ISS, in its most heavily shielded areas, has 15 g/cm2.
Future moonbases will have storm shelters made of polyethelene and aluminum possibly exceeding 20 g/cm2.
A typical space suit, meanwhile, has only 0.25 g/cm2, offering little protection.
Skipping the VABs
An inclination of exactly 90 degrees is a polar orbit, in which the spacecraft passes over the north and south poles of the planet...
At 90° inclination, solar flare protons of 7 GeV with a majority at <0.5 GeV are prevalent. Electrons are reported to be present at a higher density compared to an orbital
What I couldnt find:
Missions through the belt, to the moon using animals, or other biological life.
This I find very strange. Would they just send men to the moon without first sending a chimp? Or even a rabbit? The Soviets did it.
I couldn't find actual radiation readings to make comparisons. Or that were compared. What I found were circular arguments... such as:
February 17, 2004: NASA has a mystery to solve: Can people go to Mars, or not?
"It's a question of radiation," says Frank Cucinotta of NASA's Space Radiation Health Project at the Johnson Space Center. "We know how much radiation is out there, waiting for us between Earth and Mars, but we're not sure how the human body is going to react to it."
Apollo astronauts traveling to the moon absorbed higher doses--about 3 times the ISS level--but only for a few days during the Earth-moon cruise. GCRs may have damaged their eyes, notes Cucinotta. On the way to the moon, Apollo crews reported seeing cosmic ray flashes in their retinas, and now, many years later, some of them have developed cataracts. Otherwise they don't seem to have suffered much. "A few days 'out there' is probably safe," concludes Cucinotta.
Huh? Probably? Would you bet someone's life on that?
Some sources:
www.stevequayle.com/ARAN/rad.conversion.html
www.oulu.fi/~spaceweb/textbook/radbelts.html
home.bway.net/rjnoonan/humans_in_space/humans.html
www.sciencedaily.com/releases/2005/12/051224093605.htm
science.nasa.gov/headlines/y2004/17feb_radiation.htm