Correction should be sea instead of plain, the plain of tranquility is from a game

Posted in post 472, previous page

Oh and also have you seen how flimsy the little legs on the lander were? yes the gravity on the moon is less but that doesnt change its inertia from its velocity. it would of cratered on the moon. How did they exactly go from 1000miles an hour to a gentle touch down when theres barely any atmosphere on the moon? I dont think they had ion thrusters back then.

And this rover they brought....Why would you even bring that stupid golf cart to the moon? where are you going to go with it?

Did you know that NASA was founded by nazi scientists that came to america after ww2?

Anything passing through this belt not sheilded in 2 inches of lead would get radiated to a crisp. Electronics and equiptment arent damaged by it but living flesh is fried.

The moon is past the van allen belt. You can stay in orbit of the earth without going into this radiation belt like the space station. But to get to the moon you have to go through it.

Oh and also the door on the lander is too small to fit through wearing a space suit.

Oh and also have you seen how flimsy the little legs on the lander were? yes the gravity on the moon is less but that doesnt change its inertia from its velocity. it would of cratered on the moon. How did they exactly go from 1000miles an hour to a gentle touch down when theres barely any atmosphere on the moon? I dont think they had ion thrusters back then.

And this rover they brought....Why would you even bring that stupid golf cart to the moon? where are you going to go with it?

It was a total farce to get funding for NASA's black ops.

Did you know that NASA was founded by nazi scientists that came to america after ww2?

The Van Allen Belt

Dear sir, I wonder if you could tell me exactly what the VAN ALLEN BELT is and how much radiation does it contain, i.e. how many rems of radiation are there out there?

Plus, what protection would organic life need to be protected from this radiation?

Reply

The radiation belts are regions of high-energy particles, mainly protons and electrons, held captive by the magnetic influence of the Earth. They have two main sources. A small but very intense "inner belt" (some call it "The Van Allen Belt" because it was discovered in 1958 by James Van Allen of the University of Iowa) is trapped within 4000 miles or or so of the Earth's surface. It consists mainly a high-energy protons (10-50 MeV) and is a by-product of the cosmic radiation, a thin drizzle of very fast protons and other nuclei which apparently fill all our galaxy.

In addition there exist electrons and protons (and also oxygen particles from the upper atmosphere) given moderate energies (say 1-100 keV; 1 MeV = 1000 keV) by processes inside the domain of the Earth's magnetic field. Some of these electrons produce the polar aurora ("northern lights") when they hit the upper atmosphere, but many get trapped, and among those protons and positive particles have most of the energy .

I looked up a typical satellite passing the radiation belts (elliptic orbit, altitude ranging from 200 miles to 20000 miles) and the radiation dosage per year is about 2500 rem, assuming one is shielded by 1 gr/cm-square of aluminum (about 1/8" thick plate) almost all of it while passing the inner belt. But for ourselves no danger exists. The way these particles move in the magnetic field prevents most of them from hitting the atmosphere, and the few scattered into orbits that intersect the ground, are absorbed by the atmosphere before they get very far. Even the space station would be safe, because the trapped orbits usually stop above it--any particles dipping deeper down are lost much faster than they can be replenished.

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89. Effects of Radiation beyond the Van Allen Belts
I have over 10 years background in nuclear physics, especially dealing with the effects of radiation on the body. You never quite answer the questions about how were the Apollo astronauts protected from radiation beyond the Van Allen Belts. These are my issues:

* The Federal limit for exposure to US workers is 5 REM/year (10CFR835). Did NASA's Apollo astronauts get special permission to exceed this limit for the Apollo missions? 25 Rad = 25 REM. Their travel through the Van Allen Belts and the amount of time they spent outside the Belts would have given them doses far beyond this limit.

* NASA has never directly addressed how the Apollo astronauts were shielded. Lead is the only effective shielding (which was not used during these missions). The radiation levels outside the Van Allen Belt far exceed the 200-300 RADs inside the belts. Again how were they shielded? Regardless, their doses would at least have made them sick from radiation exposure to skin and organs even if it didn't kill them. None of them suffered any ill effects.

* Apollo astronauts were not protected from solar flares which were at their worst during this period. There is no way that the dose reports from the missions are accurate.

Thank you for your response!
Reply
Here are quick answers to your doubts:

1. I suspect that the Apollo astronauts did exceed EPA permissible doses of radiation--not by enough to pose danger to life, but above the level accepted for the population in general. Knowing NASA's concern with bureaucratic protocol, I would not be even surprised if astronauts were made to sign a waiver.

So what? If I were an astronaut candidate, I would sign such a waiver in a heartbeat. If I am about to be launched atop a giant rocket into the vacuum of space, perhaps to the Moon, certainly facing a fiery reentry before returning home--then the risk from a moderate dose of radiation ranks far below other dangers!

2. The actual dosage may be 25 Rad in the inner belt, (though probably less, see below). The radiation rates in the outer belt are smaller, not larger. Lead, by the way, is not an especially good shield: it is wonderfully efficient in excluding x-rays of, say, 100 keV, but radiation in space consists of particles, fast electrons and ions. The inner belt is mostly protons of about 50 MeV and is not very penetrating--the spacecraft heat shield, tanks etc. may shield the occupants somewhat, the interior of their bodies gets less radiation, too and lying close together during the belt passage they also shield each other somewhat.

Electrons of MeV energies in the outer belt are more penetrating, but there are not enough of them. Remember--communications and weather satellites operate in synchronous orbit, in the heart of the outer belt, year after year!

3. Solar flares can emit ions of 0.5 to 5 GeV, and these are bad, if intense enough. Such events however are rare, and when they occur, the dosage is usually not lethal, though the margin is smaller. For the Apollo astronauts, this was another calculated risk, and nothing happened.

Now if you were to fly to Mars--a trip of 8.5 months each way, plus a forced wait on Mars, whose atmosphere is too thin to protect--solar eruptions could be a problem requiring attention (though not insoluble). But we are not at that stage yet.

It was a total farce to get funding for NASA's black ops.

Did you know that NASA was founded by nazi scientists that came to america after ww2?

Did you know that NASA was founded by nazi scientists that came to america after ww2?