Apollo 13

[sts60]

NASA Manned Spacecraft Center, AIAA Paper NO. 69-17, Apollo 4 and 6 Radiation Results, 1969:

A primary objective of the Apollo 4 and 6 missions was to obtain radiation measurements inside an Apollo command module while passing through the most intense portions of the trapped radiation belts...
The analysis of the Apollo 4 and 6 data indicated that dose calculations for manned lunar missions which pass through the more intense portion of the trapped radiation belt are reliable and that the expected doses are well below the planning operational dose limits set by NASA...

...Apollo 4 and 6 trajectories followed roughly the same path through the inner belt, the Apollo 6 trajectory spent more time in the region of highest proton intensity (as shown in Fig. 9) and, therefore, should have encountered more radiation dose... (my note: which it did!)

...Dose calculations for the Apollo 4 and 6 missions are within a factor of 2.5 when compared with the Integrating Radiation Dosimeter measurements. These
errors are well within the state of the art for such complex computations. Although the need for a more accurate model of the trapped radiation environment is indicated, the results of the radiation analysis lend a great deal of confidence to the use of analytical computations for mission planning. These flights show that there will be no biological hazard associated with passage through the trapped radiation belts during the translunar and transearth phase of Apollo lunar missions, providing that there are no further high-altitude nuclear tests and that astronaut activity is confined to the command module during belt passage.

[Zakalwe]

Allancw:
Are you prepared to even acknowledge that the test that you put out there has been answered? You were on the board yesterday, so you are reading this.
Are you able to admit that you have been corrected?


If not, then it's clear that you are wilfully ignorant. I personally can not understand why anyone would be so wedded to their ideas* that they are so willing to close their minds to learning something new.
Wilful ignorance really is the most cowardly of intellectual paths to choose. I'd hate to allow my mind to become so closed that I stop enjoying learning new things. Sad really. And totally ironic that people like this are the ones that use the catcalls of others having closed minds.

<shakes head and walks away>



*Lets face it, they aren't even your own ideas. You've picked these notions up from others.

[ka9q]

...Apollo 4 and 6 trajectories followed roughly the same path through the inner belt, the Apollo 6 trajectory spent more time in the region of highest proton intensity (as shown in Fig. 9) and, therefore, should have encountered more radiation dose... (my note: which it did!)

Very interesting! I didn't know this had been true for Apollos 4 and 6. Looks like 6 in particular passed right through the center of the inner belt. Does that reference give any dosimeter readings? It would be interesting to see what a worst case looks like.

[sts60]

I can't get at the paper right now, but I'll check when I can.

The interesting thing I've learned from answering Allan's question is how thoroughly the VAB transit had been deprecated as a crew hazard relatively early on in the program.   Well before Apollo 8 headed for the Moon, the only really major radiation hazard for the short Apollo missions was known to be solar protons in cislunar and lunar space.  While avoiding the worst parts of the inner belt was desirable to minimize dosage, strictly speaking it wasn't necessary to avoid harm precisely because of the "run like hell" approach Allan scoffed at. 

At least that's my understanding at this point, so thanks to Allan for prompting this learning experience.

[Noldi400]

In either case – a partial shutdown of the cooling system only, or a total shutdown with the LM sitting on the moon – I don't see any contradiction between what Bean said and the case of Apollo 13.

Well, of course not.  A spacecraft in deep space is in a totally different environment from one sitting on a surface that is reflecting solar radiation onto the craft, besides which I would think that at some point the surface absorbs enough energy to begin radiating on its own (bit of a SWAG on my part).

In any case, I took Bean's statement to mean that, left long enough with no provision for cooling, thermal equilibrium would eventually be reached.

The interesting thing I've learned from answering Allan's question is how thoroughly the VAB transit had been deprecated as a crew hazard relatively early on in the program.   Well before Apollo 8 headed for the Moon, the only really major radiation hazard for the short Apollo missions was known to be solar protons in cislunar and lunar space.  While avoiding the worst parts of the inner belt was desirable to minimize dosage, strictly speaking it wasn't necessary to avoid harm precisely because of the "run like hell" approach Allan scoffed at. 

That was also my impression. From the transcripts, no one even thought it worth mentioning when the cleared the VAB.  The crew was quite busy with T&D, getting stowage squared away, and so forth.  There's no hint that anyone was anxiously eyeing their dosimeters.

^{Edited due to a *&$%^* sticky 'a' key.}

[Tanalia]

A short excerpt from the Apollo 4 report:

5.20.3 Radiation Monitoring
There were three radiation monitoring instruments, an integrating radiation dosimeter (IRD) and two nuclear emulsion spectrometers (NES), onboard the Apollo 4 spacecraft.  All three instruments were recovered successfully and returned to MSC in good condition.  The IRD measureda skin dose of 0.59 rads and a depth dose of 0.38 rads.

[ka9q]

That was also my impression. From the transcripts, no one even thought it worth mentioning when the cleared the VAB.  The crew was quite busy with T&D, getting stowage squared away, and so forth.  There's no hint that anyone was anxiously eyeing their dosimeters.

And of course they stayed inside the CM the whole time.

During the VAB crossing they probably also had the bulk of the S-IVB either behind or in front of them, which would have increased their shielding somewhat.

[ka9q]

A spacecraft in deep space is in a totally different environment from one sitting on a surface that is reflecting solar radiation onto the craft, besides which I would think that at some point the surface absorbs enough energy to begin radiating on its own (bit of a SWAG on my part).

It's not a SWAG, it's exactly what happens.

Any object in thermal equilibrium will radiate exactly as much power as it receives. If the object is light-colored, most of this power is simply reflected incident light, which from the sun peaks in the visible and near infrared. If the object is dark, the incident light that would otherwise be reflected is absorbed, turned into heat and re-radiated in the long infrared.

Note that an object that appears "light" in visible light may be dark in the far IR, and vice versa. Human skin, for example, appears jet black in the far IR no matter how much or little melanin it contains. Gold appears relatively dark in visible light but extremely reflective in the far IR.

Either way, the total emitted radiation (long + short wave) is exactly equal to the total incident radiation (long + short wave), plus any heat generated internally by the object of course.

[ChrLz]

C'mon, Allan C Weisbecker, man up!  Are you big enough to admit you blew it.. BADLY?

There is no shame in not being an expert on a topic - the shame is when you barge into a haven of folks who know their stuff, pretend to be an expert, and then, when faced with undeniable facts and logic, you can do nothing but run for it and hide.  A non-Dunning-Kruger human being would acknowledge that their guarantee was completely fulfilled and admit they were out of their depth.

Just out of interest, have you considered the facts that:
- you were able to join up freely
- anyone else is similarly able to join freely
- you did not have your posts edited or deleted and had every opportunity to put your 'case'
- you were/are not banned, and are free to post
and yet despite all of that, and despite the sad (for you) fact that no-one bothered to join up and support you even though your visit was public and 'advertised'..  you protest that this is some sort of paid/closed club?  You're a very funny guy!

Have you not also noticed that at every forum of any note (excluding the ones that obviously encourage utter stupidity), that Apollo deniers have virtually died out, overwhelmed by the truckloads of conclusive and completely consistent and verifiable evidence, and starved of any support from anyone with a clue?

FTR, I come here to learn, and see others learn.  Oh, alright, I also quite enjoy watching people who refuse to learn, implode when faced by facts and proper analysis/methodology.

When I stop learning and admitting errors (which is one of the very best ways to do that learning), then I will be of no further use to this planet.


BTW, was radiation your BEST shot? 

[sts60]

...Apollo 4 and 6 trajectories followed roughly the same path through the inner belt, the Apollo 6 trajectory spent more time in the region of highest proton intensity (as shown in Fig. 9) and, therefore, should have encountered more radiation dose... (my note: which it did!)

Very interesting! I didn't know this had been true for Apollos 4 and 6. Looks like 6 in particular passed right through the center of the inner belt. Does that reference give any dosimeter readings? It would be interesting to see what a worst case looks like.

A short excerpt from the Apollo 4 report:

5.20.3 Radiation Monitoring
There were three radiation monitoring instruments, an integrating radiation dosimeter (IRD) and two nuclear emulsion spectrometers (NES), onboard the Apollo 4 spacecraft.  All three instruments were recovered successfully and returned to MSC in good condition.  The IRD measureda skin dose of 0.59 rads and a depth dose of 0.38 rads.

Thanks, Tanalia.  Here is another excerpt showing that, yes, VAB trapped particle radiation was a hazard - just not the impossible one claimed by hoax believers (nor the straw man of "you say it's no problem at all" used by so many HBs).

The measured and calculated VABD dose rates encountered in the inner radiation belt during the ascending portion of the Apollo 6 high-altitude orbit are shown in Figure 11. Peak dose rates of 3.6 and 2.6 rad/hr for the unshielded and shielded sensors, respectively, were encountered at altitudes of 1400 and 1500 n.mi as the spacecraft passed through the most intense portion of the inner radiation belt.  The Apollo 6 dose-rate measurements indicate that extended operation of a manned Apollo CM at altitudes between 800 and 2400 n.mi. would be severely limited because of dose rates in excess of 1 rad/hr.  Astronaut activity in more thinly shielded vehicles than the CM, such as the lunar module, or space suits would most likely be prohibited at these altitudes.

Again, the primary mitigations were "go fast" and "stay in the CM", as well as "go through the less intense regions".

[ineluki]

See, the thing is, we cheat. You have to go through all the hard work of making up stuff, but we cheat by looking up independently verifiable historical and scientific facts. Having a reality-based approach to the subject matter gives us an unfair advantage.

Not to mention the fact, that while every Hoaxer seems to think he is the first genius to discover and bring up their relevations, most of the stuff has been around since the time Battlestar Galactica was a series with robotic dogs.  "All this has been claimed before, and all of it will be claimed again."

[Andromeda]

See, the thing is, we cheat. You have to go through all the hard work of making up stuff, but we cheat by looking up independently verifiable historical and scientific facts. Having a reality-based approach to the subject matter gives us an unfair advantage.

Not to mention the fact, that while every Hoaxer seems to think he is the first genius to discover and bring up their relevations, most of the stuff has been around since the time Battlestar Galactica was a series with robotic dogs.  "All this has been claimed before, and all of it will be claimed again."

Ecclesiastes 1:9?

[jetlagg]

Ecclesiastes 1:9?

BSG

Though the shows Mormon roots really do make it sound like scripture at times. :p

[JayUtah]

Ecclesiastes 1:9?

BSG

Though the shows Mormon roots really do make it sound like scripture at times. :p

Indeed, Glen Larson based a lot of the original BSG on Mormon doctrine and mysticism.  I had the opportunity to talk about this with Richard Hatch, and he said most of the cast was largely unaware of it, nor (when they found out about it later) had any problem with it.  His opinion is that religion and fantasy fiction have always based themselves on the same archetypes.

[Noldi400]

A spacecraft in deep space is in a totally different environment from one sitting on a surface that is reflecting solar radiation onto the craft, besides which I would think that at some point the surface absorbs enough energy to begin radiating on its own (bit of a SWAG on my part).

It's not a SWAG, it's exactly what happens.

Any object in thermal equilibrium will radiate exactly as much power as it receives. If the object is light-colored, most of this power is simply reflected incident light, which from the sun peaks in the visible and near infrared. If the object is dark, the incident light that would otherwise be reflected is absorbed, turned into heat and re-radiated in the long infrared.

Note that an object that appears "light" in visible light may be dark in the far IR, and vice versa. Human skin, for example, appears jet black in the far IR no matter how much or little melanin it contains. Gold appears relatively dark in visible light but extremely reflective in the far IR.

Either way, the total emitted radiation (long + short wave) is exactly equal to the total incident radiation (long + short wave), plus any heat generated internally by the object of course.

It may have turned out to be accurate, but for me it was still a little guesswork.  From what you said, am I correct in thinking that (if we assume that the max temp of the lunar surface is 250^o C), once the surface reaches that temperature, it's radiating all the energy that strikes it?  With some probably fairly small loss to conduction to the lower layers?