Apollo and radiation

[SLF:JAQ SFDJS]

How did they know during Apollo how much radiation shielding was needed for their spacecrafts and their space suits? They are not even sure today how much shielding they will need on the return to the moon. I've read here that the Apollo astronauts were not in the Van Allen belts very long so they did not receive much exposure. But on the moon which is radioactive they were exposed to cosmic rays, solar radiation, x-rays, gamma rays, beta rays, protons, neutrons for days. Why didn't any of the Apollo astranouts get sick from the radiation?

[Moose]

You should read this page and this page for about 95% of the answer. The rest of the answer is that Apollo wasn't the first object to enter the Van Allen belts. I can't remember, offhand, the name of the probe, but I'm pretty sure I remember Jay mentioning it in the Van Allen Belt page somewhere.

[01101001]

The rest of the answer is that Apollo wasn't the first object to enter the Van Allen belts.

Wikipedia: Van Allen radiation belt

The presence of a radiation belt had been proposed by Nicholas Christofilos prior to the Space Age and was confirmed by the Explorer I on January 31, 1958, and Explorer III missions, under Dr.James Van Allen at the University of Iowa. The trapped radiation was first mapped out by Sputnik 3, Explorer IV, Pioneer III and Luna 1.

[JayUtah]

How did they know during Apollo how much radiation shielding was needed for their spacecrafts and their space suits?

Because they had been studying it continuously for nearly a decade beginning with Explorer I.

They are not even sure today how much shielding they will need on the return to the moon.

Of course they are. They just don't know yet how to reconcile it with other mission requirements and constraints. If I know how far it is to Las Vegas, but I don't know how exactly I'm going to get there, I can still tell everyone that "my getting to Las Vegas will be a problem," without intending that to mean I don't know what the goal is.

But on the moon which is radioactive...

That's news to astrophysicists.

...they were exposed to cosmic rays, solar radiation, x-rays, gamma rays, beta rays, protons, neutrons for days.

I hate to alarm you, but you're being exposed to those exact same hazards right now, as well as dozens of known carcinogens.

Why didn't any of the Apollo astranouts get sick from the radiation?

Because there wasn't as much radiation as conspiracy theorists say. A better question is why the world's astrophysicists don't seem surprised at the astronauts' general good health.

[OneHotJupiter]

I'd say better than 'general' good health. Nine out of twelve men that walked on the moon are still living and one of the deceased was in great health when an accident claimed his life , that almost ALL of them still live and breathe is a little surprising to me. Not that I'm complaining (I love those guys)

[Daryl71]

But on the moon which is radioactive

Last time I checked, everything emits radiation, even if it's only an infinitesimally small amount. It's not like the Moon's some sort of cosmic radiation sponge, and glows green during the daytime.

[TheOncomingStorm]

It is the duration of exposure, intensity, and type of radition that matters.
(this the thrid attempt to post this, the last two tries the power was knocked by lighting.)

[Drbuzz0]

It is the duration of exposure, intensity, and type of radition that matters.
(this the thrid attempt to post this, the last two tries the power was knocked by lighting.)

Absolutely correct. The type of radiation was, at least in part, high energy particles, which would be somewhat attenuated or blocked by the spacecraft and space suits. The duration during the pass through the van allen belts especially was very short. The times of the flights were not during sun storms or other hazardous times.

The amount of radiation the astronauts were exposed to was relatively small, all things considered. It might be equivalent to getting a couple of x-rays and then taking a trans-continental flight.

In theory, any radiation exposure will increase the chances of cancer because it can cause genetic damage. In practice that small an amount is unlikely to have enough effect to really notice any increased probability, especially with such a small group. And it would be far too little for any acute symptoms of radiation sickness.

[Van Rijn]

How did they know during Apollo how much radiation shielding was needed for their spacecrafts and their space suits? They are not even sure today how much shielding they will need on the return to the moon.

If they want to go back for a short visit, like the Apollo flights, they can have pretty much the same shielding. If they want to go back and stay there a bit longer, they'll need more shielding. If they want to stay long term, they'll have to have even more shielding, and prepare for the occasional solar storm.

But on the moon which is radioactive

Guess what? So are you. For instance, the potassium 40 in you accounts for a significant portion of your yearly radiation dosage. It's meaningless to say something is radioactive unless you quantify it. Pretty much everything is a little radioactive. The surface of the moon is radioactive in the same sense as you, a chunk of dirt, or ocean water is. That is to say: Not very.

they were exposed to cosmic rays, solar radiation, x-rays, gamma rays, beta rays, protons, neutrons for days. Why didn't any of the Apollo astranouts get sick from the radiation?

Because there wasn't anywhere near enough radiation to cause radiation sickness. There wasn't even enough to significantly increase their chances of developing cancer.

[Jason Thompson]

How did they know during Apollo how much radiation shielding was needed for their spacecrafts and their space suits?

Because, believe it or not, they actually did some research on the subject before they sent men there. The Moon was studied in depth, as was the space environment. Explorer satellites, Lunar Orbiter, Surveyor, Ranger, Russian Luna probes, even the Mercury and Gemini flights had radiation dosimeters.

They are not even sure today how much shielding they will need on the return to the moon.

The planned lunar missions are long duration flights. They have totally different radiation shielding requirements from the short Apollo missions. They know how much shielding they will need. They're just not sure the best way to go about it without compromising the rest of the flight too badly.

I've read here that the Apollo astronauts were not in the Van Allen belts very long so they did not receive much exposure. But on the moon which is radioactive they were exposed to cosmic rays, solar radiation, x-rays, gamma rays, beta rays, protons, neutrons for days. Why didn't any of the Apollo astranouts get sick from the radiation?

What is your source for claiming the Moon is radioactive? How radioactive is it? How does the radiaition exposure there differ from the radiation exposure here? Numbers are required, or else you are just handwaving.

[Maksutov]

You know, I'm getting really disappointed by the decline in quality (if such a thing were possible) in the HB claims over the last few years. For example, the OP didn't even mention alpha particles.

Guess they're running out of original material, which is underscored by the constant recycling of useless, worn-out, old HB claims.

[Swift]

You know, I'm getting really disappointed by the decline in quality (if such a thing were possible) in the HB claims over the last few years. For example, the OP didn't even mention alpha particles.

Guess they're running out of original material, which is underscored by the constant recycling of useless, worn-out, old HB claims.

Which is exactly why we have to go back to the moon and on to Mars, to get more material for the HBers!

[Tucson_Tim]

You guys shouldn't waste your time responding. GHGF:TTHG:SFGG (or whatever her ID is) almost never responds to the answers.

[Bob B.]

You guys shouldn't waste your time responding. GHGF:TTHG:SFGG (or whatever her ID is) almost never responds to the answers.

That is soooo rude.

I had the same thing happen to me in this thread. My answers to the OP's questions went ignored because the OP abandoned the thread after about an hour and never returned. If there isn't a forum rule against that, there should be. A person certainly doesn't have to partake in a thread if they don't want to, but if a person starts a thread they ought to be obligated to participate and acknowledge responses. It is just common courtesy.
_

[R.A.F.]

SLF:JAQ SFDJS...other than the OP, will you be participating in this thread??

Just curious...

[sts60]

SLF:JAQ SFDJS wrote: <another seagull post>


GoAT.

[JayUtah]

The general strategy for Apollo shield design was, "Build the ship as if there was no special need for radiation sheilding." Then see how much shielding you got just from the normal structure, skin, etc. If there are any serious problems, solve them at that place in the design, such as adding polymer or fibrous panels or simply using a thicker skin material. In other words, radiation shielding was not a primary design criterion. It did not "drive" the design. The CM was not intended to survive "hard" radiation, nor was any expected during Apollo missions. The more dangerous solar flares are not common enough to worry about. So you get enough shielding incidentally from the ordinary construction.

However for long-duration missions that won't work. Radiation mitigation is a primary design criterion, so we can't just re-use Apollo designs and strategies. That doesn't mean we "still don't know how to do it." I means we have a different problem now than we had. Engineers aren't put off by problems that haven't been solved yet: that's what engineers like.

[andyschlei]

However for long-duration missions that won't work. Radiation mitigation is a primary design criterion, so we can't just re-use Apollo designs and strategies. That doesn't mean we "still don't know how to do it." I means we have a different problem now than we had. Engineers aren't put off by problems that haven't been solved yet: that's what engineers like.

I have always wondered if there would be some way to generate a strong local magnetic field to protect astronauts in much the same way Earth's magnetic field protects us. Many books (Red Mars for example) have the travelers hide in the middle of large water tanks. I have not read a sci fi book that used magnetic fields. Imagine a giant MRI in the sky.

Is this even marginally possible?

[Serenitude]

I think we have done this poster as discourtesy, and would like to apologize on behalf of BAUT. Although seagull posting is quite common here, it has yet to be even 24 hours. We know little of this person and there real-life obligations. I think we're better than that, as frustrating and useless as the all-too-common seagull postings are.

Edit: Forgot response to OP: You are new, but please remember that you are expected to interact with any threads you create in the ATM or CT section. Otherwise, your posting is taken as "seagull" style, (drop a load of crap and fly off...). It's bad form, and actually bannable if repeated. Please try to keep this in mind, and avoid this appearance.

[sts60]

Well, I am generally pretty willing to give the benefit of the doubt. But the OP in this thread has had several threads with no or minimal followup to his/her original breathless "could it be...?" posts. If SLF:JAQ SFDJS eventually returns this thread and actually participates, rather than merely dropping more unsubstantiated claims or insinuations, I will be happy to apologize.

[Obviousman]

re: the radioactive Moon claim...

I'm guessing that it comes from this:

Out in deep space, radiation comes from all directions. On the Moon, you might expect the ground, at least, to provide some relief, with the solid body of the Moon blocking radiation from below. Not so.

When galactic cosmic rays collide with particles in the lunar surface, they trigger little nuclear reactions that release yet more radiation in the form of neutrons. The lunar surface itself is radioactive!

http://science.nasa.gov/headlines/y2...activemoon.htm

(my bolding)

[JayUtah]

Active shielding was considered as early as the 1960s and is still on the plate, but it requires far more power than our current spacecraft designs can generate. Plus it doesn't work for x-rays or gamma rays. But it remains a valid physical idea whose engineering time hasn't yet come.

Water makes a very good passive shield substance.

[SLF:JAQ SFDJS]

Yes, the Nasa article did state the moon was radioactive. I agree with some of the statements above.

[Van Rijn]

Yes, the Nasa article did state the moon was radioactive.

But do you now understand the context of that statement (which is, at best, an oversimplification)?

I agree with some of the statements above.

What do you disagree with, and why?

[JayUtah]

Yes, the Nasa article did state the moon was radioactive.

About as radioactive as a baked potato. The secondary radiation the article refers to is barely detectable.

[SLF:JAQ SFDJS]

I agree that we are exposed to radiation on Earth but not to the extent the Nasa astronauts would have been on the moon. The moon has been bombarded by solar radiation and cosmic radiation for billions of year. The moons atmosphere offers no protection.

[Van Rijn]

I agree that we are exposed to radiation on Earth but not to the extent the Nasa astronauts would have been on the moon.

Where on the Earth? Exposed for how long on the Earth versus how long on the Moon? For the same amount of time, astronauts on the moon received slightly more radiation than they would from natural sources most places on Earth. But compared to their total dose, on Earth, it was inconsequential. Here's an article on the subject. From there:

Radiation doses measured during Apollo were significantly lower than the yearly average of 5 rem set by the U.S. Atomic Energy Commission for workers who use radioactive materials in factories and institutions across the United States.

The moon has been bombarded by solar radiation and cosmic radiation for billions of year.

But that does not make the surface of the moon significantly radioactive. The quotation Obviousman referred to was discussing secondaries - immediate effects of high energy strikes upon the surface.

The moons atmosphere offers no protection.

The moon has no atmosphere, true. But there has to be radiation first for that to be an issue. And, yes, there was some, but not so much as to cause problems for their short stay.

[Count Zero]

How did they know during Apollo how much radiation shielding was needed for their spacecrafts and their space suits?

Because the US launched more than 40 probes to measure the radiation environment from low Earth orbit to interplanetary space. Here is a partial list:

1958 February 1 - Explorer 1: Perigee: 347 km Apogee: 1,859 km. Discovered radiation belt around Earth.
1958 March 26 - Explorer 3: Perigee: 186 km Apogee: 2,799 km. Radiation & micrometeoroid data.
1958 July 26 - Explorer 4: Perigee: 257 km Apogee: 1,352 km. Mapped project Argus radiation.
1958 October 11 - Pioneer 1: Apogee 113854 km
1958 December 6 - Pioneer 3: Apogee 102,332 km. Discovered 2nd radiation belt
1959 February 17 - Vanguard 2: Perigee: 557 km Apogee: 3,049 km. Studied magnetosphere.
1959 March 3 - Pioneer 4: Lunar fly-by, Solar orbit. Measured radiation near the Moon.
1959 August 7 - Explorer 6: Perigee: 245 km Apogee: 42,400 km. First Earth photo; radiation data.
1959 September 18 - Vanguard 3: Perigee: 512 km Apogee: 3,413 km. Radiation & micrometeoroid data.
1959 October 13 - Explorer 7: Perigee: 523 km Apogee: 857 km. Magnetic field and solar flare data.
1960 November 3 - Explorer 8: Perigee: 394 km Apogee: 1,331 km. Ionospheric research.
1960 March 11 - Pioneer 5: Solar orbit. Mapped magnetic fields in interplanetary space.
1961 March 25 - Explorer 10: Perigee: 221 km Apogee: 181,100 km. Magnetic field data.
1961 April 27 - Explorer 11: Perigee: 480 km Apogee: 1,458 km. Gamma ray data.
1961 June 29 - Injun 1: Perigee: 869 km Apogee: 992 km. Radiation data.
1961 August 16 - Explorer 12: Perigee: 790 km Apogee: 76,620 km. Radiation and solar wind data.
1962 August 27 - Mariner 2: Solar orbit, Venus fly-by. Returned radiation and solar wind data.
1962 October 2 - Explorer 14: Perigee: 2,558 km Apogee: 96,229 km. Magnetosphere studies.
1962 October 27 - Explorer 15: Perigee: 306 km Apogee: 17,610 km. Radiation decay data.
1962 December 13 - Injun 3: Perigee: 240 km Apogee: 2,406 km. Radiation decay data.
1963 November 27 - Explorer 18: Perigee: 192 km Apogee: 197,616 km. Interplanetary radiation data.
1964 August 25 - Explorer 20: Perigee: 857 km Apogee: 999 km. Ionospheric research.
1964 October 4 - Explorer 21: Perigee: 191 km Apogee: 95,590 km. Magnetic field, radiation data.
1964 October 10 - Explorer 22: Perigee: 872 km Apogee: 1,053 km. Ionospheric and geodetic data.
1964 November 21 - Explorer 25: Perigee: 526 km Apogee: 2,319 km. Radiation data.
1964 November 28 - Mariner 4: Solar orbit, Mars fly-by. Returned radiation and solar wind data.
1964 December 21 - Explorer 26: Perigee: 284 km Apogee: 10,043 km. Radiation and solar wind data.
1965 April 29 - Explorer 27: Perigee: 932 km Apogee: 1,309 km. Ionospheric and geodetic data.
1965 May 29 - Explorer 28: Perigee: 229 km Apogee: 261,206 km. Magnetic field, radiation data.
1965 November 19 - Explorer 30: Perigee: 671 km Apogee: 856 km. Solar radiation data.
1965 November 29 - Explorer 31: Perigee: 505 km Apogee: 2,833 km. Ionospheric research.
1965 December 16 - Pioneer 6: Solar orbit. Studied Solar wind and Sun’s magnetic field.
1966 July 1 - Explorer 33: Perigee: 265,679 km Apogee: 480,762 km. Magnetic field, radiation data.
1966 August 17 - Pioneer 7: Solar orbit. Monitored Solar wind and cosmic rays.
1967 May 24 - Explorer 34: Perigee: 242 km Apogee: 214,379 km. Radiation, magnetic field data.
1967 June 14 - Mariner 5: Solar orbit, Venus fly-by. Returned radiation and solar wind data.
1967 July 19 - Explorer 35: Lunar orbit, Perigee: 484 km Apogee: 675 km. Earth magnetic tail measurements.
1967 December 13 - Pioneer 8: Solar orbit. Returned Solar radiation data.
1968 March 5 - Explorer 37: Perigee: 353 km Apogee: 433 km. Solar radiation data.
1968 August 8 - Explorer 40: Perigee: 679 km Apogee: 2,489 km. Radiation data.
1968 November 8 - Pioneer 9: Solar orbit. Returned Solar radiation data.
1969 June 21 - Explorer 41: Perigee: 80,374 km Apogee: 98,159 km. Cislunar radiation data.
1971 March 13 - Explorer 43: Perigee: 1,845 km Apogee: 203,130 km. Earth magnetosphere research.
1971 July 8 - Explorer 44: Perigee: 433 km (269 mi). Apogee: 632 km. Solar radiation data.
1971 November 15 - Explorer 45: Perigee: 272 km Apogee: 18,149 km. Studied magnetosphere, energetic particles.
1972 September 23 - Explorer 47: Perigee: 201,100 km Apogee: 235,600 km. Investigated cislunar radiation, Earth's magnetosphere, interplanetary magnetic field.

[ranb]

.....Radiation doses measured during Apollo were significantly lower than the yearly average of 5 rem set by the U.S. Atomic Energy Commission for workers who use radioactive materials in factories and institutions across the United States......

Actually your link has at least one mistake. 5 rem per year is one of the limits for ionizing radiation exposure to the whole body. The average for nuclear workers is lower. For instance, Sailors and Naval shipyard workers rarely exceed 0.5 rem per year. After 23 years of receiving occupational exposure, I was extended to 0.75 rem per year allowed.

I agree the astronauts received less than 5 rem on their missions though.

Ranb

[JayUtah]

I agree that we are exposed to radiation on Earth but not to the extent the Nasa astronauts would have been on the moon.

Do you know the extent? If I asked you for a number representing mean ambient radiation on the lunar surface, could you give me one?

If you agree that radiation occurs in different amounts, and that not all amounts are immediately harmful, then you should realize that you can't just wave your hands about "radiation" without knowing how much is there.

The moon has been bombarded by solar radiation and cosmic radiation for billions of year.

That doesn't make it radioactive. Secondary radiation doesn't build up. It works like a white shirt fluorescing under ultraviolet light. You get the purple glow as long as the light is on. When you turn off the light, the shirt doesn't keep glowing. Contrary to what you see on television, exposing something to radiation doesn't generally make it radioactive itself.

The moons atmosphere offers no protection.

No one said it did. What kind of protection do you think was needed, and how do you know that?