Radiation

[bknight]

timfinch:"I am right, the rest of you are wrong".

[onebigmonkey]

I have fulfilled my quota for entertaining pompous, self-righteous know-it-alls for this quarter.  I'll check back sometime next quarter to see if the light of epiphany has shined on you guys.  Be well and be vigilant.

Diddums.

While you're gone, have a read up about the solar flare monitoring efforts in place during Apollo 11

ftp://ftp.library.noaa.gov/docs.lib/htdocs/rescue/journals/essa_world/QC851U461969oct.pdf

and perhaps consider some of the many points you ignored in favour of "yeah but what if...".

[gillianren]

Hey Gillianren, do you remember that episode of Buffy with the girl who got ignored so much that she literally turned invisible?  I sometimes feel that way with some of these HBs.  At least you got one response.  I didn't even get a nibble for the videos on page 22.  The thing is, you and I were asking a simple question that did not require any technical knowledge - just a little self-examination.  "Aye, there's the rub..."

I didn't even get an acknowledgement that I'm not a gentleman!

[raven]

I didn't even get an acknowledgement that I'm not a gentleman!

Should have pulled an Éowyn on the dastard.

[benparry]

can i just thank everybody here for this thread. i actually feel sorry for starting it all now lol

as you may have guessed my knowledge on this matter is limited and i have learned a lot.

i am correct in breaking it down to the following.

1. the GCR is not all High Energy Particles but consists of a spectrum of radiation. this means that it is quite difficult to calculate what dosage any mission should receive.

2. the Mars missions vehicle and the apollo mission vehicle were different by design (if not by radiation design) and would therefore be impossible to compare due to those differences.


if the above is correct does anybody have a diagram showing that GCR spectrum. that would be interesting.

can i also add a thought for corroboration. i read somewhere that High Energy Particles are very rare with 1 only striking the earth every hundred or so years. i am aware that the VAB would stop most but surely if they were everywhere all at the same (which i assume is Tims argument) more than 1 every hundred years would strike the earth.

is the above correct or have i confirmed my denseness on this matter.

[Jason Thompson]

To quote Mr. Spock, "Captain, his pattern suggests two-dimensional thinking."  And while we can make all kinds of noise about spatial reasoning skills, a more fair assessment points out that nearly every rendition of manned translunar trajectories you find in public-relations materials puts everything roughly in the same plane.  If you do that consistently, you can't find too much fault if people wrongly get the idea that the actual problem is all coplanar.

True, but you can find fault when they repeatedly refuse to consider the third dimension after having it pointed out several times, and even shown to them in other ways...

That said, relying on public-relations material for technical accuracy is a mistake in and of itself.

Indeed. my favourite example being the people who insist the LM must have a visible flame under it because those nice NASA artists painted it with one in the pictures for the papers.

It's not even technically necessary for the transfer orbit to be in a plane that's compatible with the landing site.  Only the final lunar orbit has that constraint.  LOI-1 and LOI-2 can be used to change the lunar orbit inclination and ascending node to access the landing site.  I say "technically" because doing those as part of the insertion maneuver would be propellant-intensive.

Thanks for the clarification, Jay. I fell into the trap of leaving out the understood parts of the argument. I figured that, given the choice between using the absolutely critical, no backup, if-we-screw-this-up-we're-boned SPS to effect a significant plane change right at the point of insertion and the whacking great J2 engine on the S-IVB to effect a TLI burn that puts you on more or less the right plane with an option for some mid-course corrections over the next couple of days to get it just right they'd go for the latter. However, presenting it as a requirement was a flawed argument. Always good to get picked up on these things. I'm out of practice!

All that a transfer orbit must technically achieve is that the spacecraft and destination coincide in the same point in space-time -- zero-order continuity.  That requires only the intersection of the transfer orbit plane with the destination orbit plane.

Indeed, and you could do this with a 90 degree angle between orbital plane and transfer plane, if you had the fuel. Provided you can slow down enough to be captured you'll go into orbit.

Now I'm curious as to the ability to conduct a lunar landing mission from a polar orbit with the Apollo configuration....

[MBDK]

Next time, I am going to run a pool on how many posts people will make before they flounce....

I think it would vary, depend on each individual HB's tolerance for having their arse handed to them. Another factor could be how long it takes before they realise they are totally out of their depth in the sheer level of knowledge and expertise here. This forum is unlike others on the web; you simply cannot bluff your way past the experts, they will spot you a mile off.

As ex-military with 20 years experience in the Avionics Trade, I am somewhat disappointed with timfinch. I didn't expect a full blown CT nutcase to come from the ranks of the US Navy, especially a technician working on Nuke subs. Disturbing to say the least.

My experiences with the Navy's nuclear personnel has been pretty positive overall, but they still had their share of "eccentrics", as well as one or two that are rightfully in prison at this time.  But that's the human condition, I suppose.

Now, for a new conspiracy theory regarding Obviousman's pool: I say he is setting us up for a sock-puppet of his to enter the fray, which will guarantee Obviousman a victory and a windfall of swag from his victims.  Prove me wrong! ..................hold on...OH NOOOOOOOOOO.....I seem to be morphing into a version of timfinch......but smarter......and better looking.........and above all, much more humble..............

[Count Zero]

I am not sure NASA ever lied about radiation.  I am sure they lied about sending men to the moon.  If I had been in their place I would have lied too.  Billions of dollars wasted and national pride on the line.  I would have lied my ass off. 

I'll just leave this right here:
Does it take one to know one? Endorsement of conspiracy theories is influenced by personal willingness to conspire

[bknight]

Hey Gillianren, do you remember that episode of Buffy with the girl who got ignored so much that she literally turned invisible?  I sometimes feel that way with some of these HBs.  At least you got one response.  I didn't even get a nibble for the videos on page 22.  The thing is, you and I were asking a simple question that did not require any technical knowledge - just a little self-examination.  "Aye, there's the rub..."

I didn't even get an acknowledgement that I'm not a gentleman!

Uum I thought about that but since we were being bombarded by some rather discourteous one liners, I stopped, sorry.

[Jason Thompson]

can i just thank everybody here for this thread.

You're welcome.

i actually feel sorry for starting it all now lol

No need to feel sorry. It's good to get into a debate. The only thing I'm sorry about is his lack of staying power. Two days of intense activity followed by a flounce. One of the shortest we've had I think.

as you may have guessed my knowledge on this matter is limited and i have learned a lot.

The last five words of that sentence are what sets you apart from Tim....

1. the GCR is not all High Energy Particles but consists of a spectrum of radiation. this means that it is quite difficult to calculate what dosage any mission should receive.

Not only a spectrum but variable over time, influenced by solar activity, and several other variables that Tim seemed unwilling to believe existed or influenced the radiation levels sufficiently to matter.

2. the Mars missions vehicle and the apollo mission vehicle were different by design (if not by radiation design) and would therefore be impossible to compare due to those differences.

Essentially correct as far as I understand it, since radiation exposure is entirely dependent on what is between you and the source. Tim insisted we 'lack the technology' to shield GCRs. That's not strictly true, since sticking anything in between you and the source will shield to some extent. The question is how much and what is acceptable for the mission requirements and crew health.

He also insisted on using averaged data without considering error margins. Another of his oversimplifications. Here's an illustration of why:

Imagine you are in space for 10 days and you measure the radiation exposure every day. In the units of choice anything under 10 is 'safe', anything over 20 increases your likelihood of getting cancer in the next 20 years by 50% and anything over 30 will see you dead within 24 hours of exposure. Let's say on that mission your data set looks like this:

6,6,2,3,3,4,7,6,5,8

Average that out and you have experienced a mean of 5 units per day on the mission. A safe mission.

Now imagine someone else goes up and the data set looks like this:

2,1,2,1,3,2,33,3,2,1

If you look at the average there's a mean of 5 units per day of exposure, so looking at that data set you would conclude it was safe. However, there was a spike over 30 in the middle of that, so the reality is your astronaut was dead before they came home. The average data (safe daily levels for both missions) and the observed reality (one healthy and one dead astronaut) don't match, so you can't use it to compare the two missions directly.

is the above correct or have i confirmed my denseness on this matter.

I can't comment on your HEP query as I am unqualified to do so, however, don't confuse ignorance and 'denseness'. Everyone is ignorant of something, and in the case of complex fields like radiation more people are way more ignorant than others because it takes a lot of study to get a real grasp of it, and it's an evolving science anyway. You may be ignorant, but your willingness to listen and learn counts against any suggestion of 'denseness'.

[benparry]

Great stuff thanks a lot Jason.

[Jason Thompson]

Do you realize Jason is a professional scientist?  His opinion would be considered evidence in a court of law.

Thank you for the vote of confidence. In the interests of transparency however, I should say that I am a biochemist and not a qualified expert on any matters of radiation, so my opinion in a court of law on a subject involving radiation really shouldn't hold too much sway.

To the broader point, however, it does raise the question of where the line is between accepting the testimony of a professional expert and requiring them to provide corroboration. Someone asked to testify on a matter in their field in which their opinion is based on their accrued knowledge rather than ability to point to a specific reference would quite probably be unable to cite a specific publication or report simply because it would be lost in the pool of knowledge they have acquired. As it was when I brought up the plan to orient the spacecraft to put the bulk of it between the crew and the sun. I know that was the plan, I've read it in many sources over the last few years, but I could not point anyone to the precise document from NASA that describes it, as some HBs would have me do.

It reminds me of an argument at work some years ago when a debate about expiry dates of a component came down on the side of having to expend significant time and resource gathering evidence that the performance did not degrade over time when all of us on the technical side knew it wouldn't because apparently the argument 'we've known how this chemically inert stuff that is used all over the world for many applications including several that are identical in all significant respects to our intended use behaves for literally centuries' was insufficient because we could not provide a specific documented justification that it would work in this instance. Of course, the other side couldn't provide a documented justification to show how anything we were doing differed from these other instances either, but never mind....

[bknight]

can i just thank everybody here for this thread. i actually feel sorry for starting it all now lol

as you may have guessed my knowledge on this matter is limited and i have learned a lot.

i am correct in breaking it down to the following.

1. the GCR is not all High Energy Particles but consists of a spectrum of radiation. this means that it is quite difficult to calculate what dosage any mission should receive.

2. the Mars missions vehicle and the apollo mission vehicle were different by design (if not by radiation design) and would therefore be impossible to compare due to those differences.


if the above is correct does anybody have a diagram showing that GCR spectrum. that would be interesting.

can i also add a thought for corroboration. i read somewhere that High Energy Particles are very rare with 1 only striking the earth every hundred or so years. i am aware that the VAB would stop most but surely if they were everywhere all at the same (which i assume is Tims argument) more than 1 every hundred years would strike the earth.

is the above correct or have i confirmed my denseness on this matter.

tim has tried on two different forums CosmoQuest and here to show his ineptitude and been handed his hat to him.  More than those here attempted to steer him towards a better understanding of radiation and away form the "average" rate he has embraced, without thinking trough the error bars as Jason has indicated in his last post.
If he really wanted an apple to apple comparison, I believe he should obtain the Curiosity radiation set  and look at the values taken from launch to 238000 miles for an average look.  I'm not sure how the flux varies over distance from the source, nor I have I looked into it.  Those "dummies" at NAS have the data and will no doubt make the best optimal use of mission parameters/components to insure a successful mission to Mars in the future.

[bknight]

Do you realize Jason is a professional scientist?  His opinion would be considered evidence in a court of law.

Thank you for the vote of confidence. In the interests of transparency however, I should say that I am a biochemist and not a qualified expert on any matters of radiation, so my opinion in a court of law on a subject involving radiation really shouldn't hold too much sway.

To the broader point, however, it does raise the question of where the line is between accepting the testimony of a professional expert and requiring them to provide corroboration. Someone asked to testify on a matter in their field in which their opinion is based on their accrued knowledge rather than ability to point to a specific reference would quite probably be unable to cite a specific publication or report simply because it would be lost in the pool of knowledge they have acquired. As it was when I brought up the plan to orient the spacecraft to put the bulk of it between the crew and the sun. I know that was the plan, I've read it in many sources over the last few years, but I could not point anyone to the precise document from NASA that describes it, as some HBs would have me do.

It reminds me of an argument at work some years ago when a debate about expiry dates of a component came down on the side of having to expend significant time and resource gathering evidence that the performance did not degrade over time when all of us on the technical side knew it wouldn't because apparently the argument 'we've known how this chemically inert stuff that is used all over the world for many applications including several that are identical in all significant respects to our intended use behaves for literally centuries' was insufficient because we could not provide a specific documented justification that it would work in this instance. Of course, the other side couldn't provide a documented justification to show how anything we were doing differed from these other instances either, but never mind....

That being said, you do possess the professional habits of looking at data, authors, presentation and ask the real world questions that a scientific mind should ask.  tim does not have those abilities as he look at two sets of data and concluded one of them must be faked, instead of asking the question what factors are present in each set that MAY make both correct and still look entirely different, to an unprofessional mind.

[benparry]

yes i introduced him there also lol i believe a gent called grant engaged him there a lot