Merged Apollo "hoax" discussion / Lick observatory laser saga

[SUSpilot]

The fundamental point Robrob is that a bicycle is a much more sophisticated , much more complex machine than an airplane or rocket..Once you understand that, you are home free......

Oh, for pity's sake. Notwithstanding Jay's reply, the engine in a Cessna 172 is orders of magnitude more complicated than a bicycle.

Give it up, already.

 

[SUSpilot]

Wait a second.

I'm a flight instructor. I'm pretty good at it. I really want to hear you explain this, because it will help establish for me your claimed expertise in yet another field.

Please do not tell me to go read about the Wright Brothers. I am far more interested in how you relate the turning of a bicycle to how an airfoil causes an aircraft to turn.

Patrick, I think I can empathize with Jay here for being ignored.

Since you brought it up before (and have brought it up again), I asked this very specific question of you, both here and in the unmoderated thread you started regarding bicycles, stilts, and airplanes. Do I get an answer from you or not?

 

[JayUtah]

...and depending on conditions/seeing.

So when grizzled old sailors talk about a varying ability to see stars, it's okay. When Apollo astronauts talk about varying ability to see stars, somehow that's proof of fraud. You don't seem to understand that the rest of the world sees these as roughly equivalent cases. They don't buy into your straw-man oversimplifications because they have personal experience with varying visibility of stars.

You need to sight stars to align your IMU. You stop the PTC, face away from the sun, cover the shades and fully dark adapt.

No, that is not the procedure. The CM is not darkened in preparation for P52. While the CMP is down in the LEB checking the platform alignment, the other crew members are performing other duties and thus require cabin lighting etc.

Charlie Duke was describing casual observation of the sky in the excerpt you discuss. At all other times, when giving primary testimony regarding his navigation duties aboard the LM, he described the visibility of stars very differently. That's because they are two different cases with different circumstances. Looking through the optics for a few seconds produces the needed dark adaptation.

You scan into the pitch black star punctuated sky, looking down sun. What constellations would you see, where, when , how, why?

You don't see constellations through the sextant, nor are your expected to. You're manufacturing new "requirements" again.

More stars than one would see from earth...

Asked and answered. You were asked, for each of the Apollo guide stars, to name the similar-magnitude stars within the sextant FOV. Since you haven't done that after having been repeatedly asked, I think it's safe to say that you know you're bluffing about the "confusing" stars.

How do you know which star is which?

Because it's the one almost in the reticule.

Since you still haven't researched how often platform alignment checks were performed, you don't know the expected drift. It is a very small fraction of a degree under normal operations. Under coarse-align conditions, the SCS coarse alignment procedure puts the guide star in the FOV.

And if there is any uncertainty, you mark three stars instead of just the two required by the degree of freedom. I covered this at length before.

The nominal case is the drift-detection check. Those are on the order of a small fraction of a degree. The stars nearest the center of the field of view are at first assumed to be the appropriate stars. By the way, this is how your highly-praised Apollo-era automated systems worked. They used the existing alignment as the seed for their search. No one starts from scratch.

The next line of defense is the SCS coarse alignment. If, for any reason, the guide stars are not already in the sextant, and a manual search is uncertain, the SCS can be used as an alignment reference to get the stars close. The automatic star trackers you refer to in other systems, and the ones used on the space shuttle, would only work if the spacecraft were already coarsely aligned. They aren't magic star-finders.

Only as a last resort must the navigator scan the skies, identifying stars by constellation and manually plugging them in. None of the other star-tracking systems you mentioned can provide an initial fix. Only with today's third-generation systems from the Ball Brothers can you get an initial fix automatically from the stars, and that only after 60 seconds of computation, and then only to a certain confidence.

The more you try to portray Apollo as an inferior or unworkable system, the more you demonstrate you don't know anything about this science.

You have not trained for this.

Nonsense. The astronauts trained extensively with astronomers, and they were pilots with navigation training prior to NASA. The only one in this discussion who has not trained for this is you.

Your computer likewise is not programed for it.

Straw man. You're still trying to shoehorn the requirements of different systems into the Apollo system. In the Apollo system the human navigator is given the most difficult part of the task, which even with today's computer technology produces an alignment with only about p ~ 0.9 confidence. The rest is handled by the computer. Since I've already discussed this at length previously, I'll assume you're just choosing to ignore it and I won't repeat it.

Sailors navigate, Apollo astronauts play pretend space sailor.

I asked you repeatedly whether you have navigated any INS-guided vehicle. It's clear at this point that you have not. Why should anyone trust your expectations over those of people who have actually navigated?

Don't let 'em jive you tsig. Apollo is one big fat SCAM........

You need to understand that not everyone with whom you're conversing simply regurgigoogles as you do. You need to understand that many of us know these things not because we've been told them by people whom we trust, but because we have done them ourselves. It's very, very difficult to scam someone who has personal, practical knowledge and experience, especially when all you can offer on the other hand is ever-changing supposition and carefully mined quotes.

 

[Tomblvd]

I am a doc

If you are referring to any kind of medical doctor, you most certainly are not.

A person knowledgeable in basic medicine would know that contact with someone suffering from the flu does not automatically guarantee infection. Also, even undergrads know that no vaccine is 100%.

Your backpedaling notwithstanding, you did make both assertions earlier in the thread.

You are not a doctor of any kind of normal medicine.

 

[sts60]

Of course he did not tell me how in that post, that is ridiculous Loss Leader......

WHAT, Did they, in Jay's terrestrial lab, subject to near absolute zero and then heat up a live, tritium containing warhead(replete with fission component) to the same temperature that would be realized when said warhead would actually fly through space and then the atmosphere under battle conditions?...

Says the man who knows nothing about aerospace engineering but still thinks that his opinion should count for more than those who do.

Patrick1000/fattydash/DoctorTea once again demonstrates not only that he Has No Idea What He's Talking About, but also that he simply will not learn from people who actually do. Yes, Jay did indeed explain to him how things are done. But he not only refuses to learn, he also refuses to even recognize when the opportunity to learn is presented to him.

Disregarding his bizarre reference to "absolute zero" - which is irrelevant to ICBMs - and "battle conditions" - the latter is meaningless handwaving by a layman - he simply cannot grasp that ICBM design, like spacecraft design, is based on understanding the properties of the vehicle and the environment in which it will perform, and that this understanding is achieved through a mix of analysis, numerical simulation, and various types of testing.

Ballistic missile design was verified and validated in ways entirely appropriate for the application. Warheads were detonated in a variety of ways - including airdrops and even a complete end-to-end ballistic shot (Frigate Bird) - but there was an enormous amount of work done on the ground, including materials property research and computer simulation. The effect of the reentry environment was studied in wind tunnels which generated various durations, speeds, and temperature ranges of atmospheric flow. This provided the necessary knowledge of the aerodynamic and thermal effects.

The interplay of analysis and numerical modeling with physical testing - component, subsystem, aerothermodynamic, and, yes, flight, all of which were performed - was standard practice then just as it is now. The mix has changed as numerical modeling has become, well, "faster, better, and cheaper", and been extensively validated against test results, but the multidisciplinary practice is part of a continuum that spans many decades of missile, spacecraft, and commercial and military aircraft development.

And, yes, it really is aerospace engineering. A layman like Patrick1000/fattydash/DoctorTea/etc. doesn't even begin to grasp what it is involved and, frankly, has no business offering his ignorant opinions as even a good guess at how it should be done, let alone as fact.

For example

The big question is what happens to the hot stuff. Instruments are not the same thing as tritium, nor the same thing as plutonium nor uranium. No instrument can substitute for the weapon material.

No, they're not. And plutonium and uranium are different from each other, but uranium oxide is routinely used as a simulant for plutonium oxide (²³⁸PuO₂) oxide in isotope heat source testing, because it does not require the same precautions and containment provisions. Such tests validate the heat source design and modeling, including reentry modeling. And heat sources (like those used on Cassini, Mars Science Laboratory, etc.) use materials originally developed for missile nosetips because of their suitable and well-characterized properties.

Consider that every isotope generator (and their heat sources) ever launched by the U.S. have performed as designed, including in the case of accidents. None were ever tested according to Patrick1000/fattydash/DoctorTea/etc.'s cartoon views. But they were proven through design, analysis, simulation and appropriate test, and the sources used over the past couple of decades are based on the missile reentry technology - in this case, to survive a reentry and impact "intact" (meaning that the isotope fuel is contained). I've "been involved" - as in witnessing such testing, and actually generating recommendations for use of limited test resources - in this. Unlike the Third Wright Brother, I do know what I'm talking about.

I would suggest at this time that Apollo was a program focusing on other aspects of our ICBM programs(offensively, defensively). Mercury seems to have been a warhead viability program, full contact missile flight program. Of course they need to test wardheads throughout, but by Apollo, one would think they have better things by and large to do with their insanely expensive launches and limited cargo hoisting abilities.

What? Mercury was simply America's first manned space program. Why would you think it was a disguised military program? This was the height of the cold war, so there would be no need to hide a weapons program as most Americans wanted to bigger and better missiles than the Russians. The American public would have approved of another waeapons program, so why ghide it?

Multivac is correct that there was no need to camouflage a weapons program. Not only was the actual ballistic missile development and test program very robust - something Patrick1000/fattydash/DoctorTea/etc. does not grasp - doing it the way he proposed would have been detrimental to the program.

First of all, his handwaving about "full contact" test is meaningless. He can't define it, because he jumps back and forth from insisting that ICBMs had to be tested by actually firing a live nuclear missile toward the Soviet Union - an excellent way to start World War III - to insisting that they had to be tested with manned lunar mission designs. That's not a test plan; it's a collection of random neural firings.

Second, his "plan" ignores the actual and very thorough development and test regime, which I've touched on above. That's because he spends his time frantically Googling sciency-sounding things instead of actually learning anything about how aerospace and weapons tests are actually performed. Worse, as already mentioned, he refuses to even recognize the opportunity when it is served up to him here on this forum; he just keeps leaning on the transmit key and ignoring the fact he's not fooling anyone. At all.

Third, his fantasy approach is the last way anyone wanting to actually qualify such weapons for use would take. It's useless because it does everything except test the actual operational systems. While Atlas and the Titan II were developed as ballistic missiles, the vehicles were modified and the flight profiles were different - only a few were suborbital flights, and the reentry systems were completely different. There was nothing to be gained from trying to disguise ICBM tests this way, and Patrick1000/fattydash/DoctorTea/etc. contradicts himself by suggesting it. And, of course, and as usual, P1k/fd/DT/etc. also has absolutely no evidence whatsoever for such a claim. Throwing in Apollo and Shuttle is just stuffing another clown into the little car.

With Mercury they had quite a few unmanned launches, those must have been with "live nukes". Perhaps nukes without triggers, but aside fram that, they were Atlas contraptions testing the weapon system's overall integrity in the context of an actual firing.

Of course there were unmannned launches, to test the mercury capsule. Also, the launch vehicles used, Redstone and Atlas, were not initally man-rated as they were ICBMs without the warheads. Wouldn't you want some confidence that the launch vehicles were safe enough to launch people into space?

Of course, men were launched into space on these vehicles; they were strapped into the vehicles, monitored during the flights, and tracked during the flights and subsequent reentries.

But what really stands out here is Patrick1000/fattydash/DoctorTea/etc.'s complete inability to construct even a coherent narrative, let alone an even remotely believable one - which is especially funny in light of his claims to be a "writer".

He says you have to test nuclear missiles "live", except that they aren't "live" after all. He says to be sure a functional missile will blow up something in Russia, you have to fire it towards Russia and make sure it's not actually functional [ETA] and doesn't actually hit Russia. He says Apollo was used to place LRRRs on the Moon [ETA] for secret military purposes, that Apollo was used to test ICBM technology, that Apollo couldn't have reached the Moon, that the LM could navigate and land itself, that the LM couldn't navigate and land even with a crew.

Now he insists he's some sort of super bicycle engineering wizard and international consultant, and that bicycles are more complex than ships that carry hundreds of people across the planet, orbit the Earth, and explore the outer planets and roam Mars. Based on his, er, thoughts, I would guess his plan for testing a bicycle is to tune in a television to an advertisement for tricycles, then to set the TV on fire and use a trebuchet to fling it at the nearest group of sea lions.

Patrick1000/fattydash/DoctorTea/etc. does not have the faintest idea what he's talking about. He fabricates his qualifications, denies his own posting history, and routinely invents "facts" which don't exist. He has no evidence for anything he says. He won't listen to actual experts here on the board, pretends to read books that Google Books excerpts, frequently contradicts himself, and makes use of embarrassingly juvenile language and taunts at qualified people, but runs away from actually confronting them when given the opportunity. I see no point in responding to anything else of his even in quoted form.

 

[nomuse]

The fundamental point Robrob is that a bicycle is a much more sophisticated , much more complex machine than an airplane or rocket..Once you understand that, you are home free......

Free of any taint of logic, that is.

 

[Alferd_Packer]

Vehicle | Part Count
bicycle | 200
automobile | 2,500
Boeing 747 | 6,000,000

By one common measure of engineering complexity (part count) an airliner is thirty thousand times more complex than a bicycle. In fact, it takes 270,000 specialized tools alone to build an airliner.

Your claim is patently absurd.

Yeah, but what's the part count on the Wright Flyer? Hmmmm Mr. Smarty Pants?

Wings
Frame
Stabilzer
Engine
Seat
some baling wire.

a modern racing bike is way more complex.

 

[nomuse]

How do you know which star is which? Well, you know the same way I did, the first time I found myself stargazing in a place without light pollution: The bright stars are the principal stars in the constellations. I learned the constellations when almost all I could see was the major stars. It took a few minutes to get used to having a clutter of lesser stars in between, but it really isn't that hard.

If you're an experienced navigator, for example, you will already be perfectly used to picking out those principal stars from a dense field of lesser ones. And indeed you'll be used to operating in all sorts of seeing conditions, from only being able to see a handful of stars to seeing hundreds or thousands. If you now add more even dimmer stars, the familiar task of picking out patterns of bright stars will remain the same.

Do you have any evidence to support your contention that this will be difficult? My direct experience says it's not.

By the way, can you justify your claim that "you have not trained for this" or expand on exactly what you meant by "your computer is not programmed for it"?

Or you do the usual "arc to Arcturus" routine...

If viewing is bad and/or I have completely lost track of the season, I look for Orion. If nothing else, there is no-where else in the sky where there are two bright stars -- one slightly reddish, one slightly blueish -- of that spacing. And once I've oriented to Orion, I can start working my way towards Pegasus or where-ever the current point of interest might be.

 

[abaddon]

I am a doc

Why are you not a member of the AMA, then?

 

[nomuse]

Also occurs to me that...here we are, worst-chance scenario, capsule was tumbling and INS is off and we have to figure out our orientation from scratch.

First place I'd look? Not for constellations! I'd look to see where the Sun was. And possibly the Moon and Earth. And look for planets, too...that would help me figure out where the ecliptic was. If had as much as one of those cardboard star finders you used to be able to buy from Edmund's Scientific, I'd know where my stars of interest should be found before I'd even dark-adapted enough to see a star!

Seems to me what Patrick is describing in terms of finding a guide star is oddly similar to how he describes testing procedures for aerospace; as an all-up, one-shot, package deal. No iterative methods, no divide and conquer, no top-down; just solve the entire problem at the desired level in one shot.

I am NOT an engineer. I am in a technical field, though, and I'd never get anywhere if I tried to problem-solve like this.

 

[JayUtah]

Yeah, but what's the part count on the Wright Flyer? Hmmmm Mr. Smarty Pants?

A better paragon would be the Wright Model B, which is their production aircraft. It has about 800 parts, including the engine. The one I can inspect whenever I need to is a surviving Burgess-Wright Model F, a license of the Model B design.

Wings
Frame
Stabilzer
Engine
Seat
some baling wire.

a modern racing bike is way more complex.

Seat
Pedals
Chain
Wheels
Frame
Fork
Brakes

Naw, not really.

Yes, tongues firmly in cheek, but think about it. If you want to compare a 1912 aircraft to a 1912 bicycle, the 1912 aircraft is still more complex. If you want to compare a 2012 racing bicycle to a 2012 production aircraft, again there's no comparison.

You name assemblies as if they were parts. So did I, with respect to the bike, for the same humorous purpose. When you say "Wing," that means just under a million parts for each of two airliner wings. For the Wright Model B it's about 300 parts for each of the upper and lower wings. And similarly a "Frame" for a bicycle is welded together out of machined and forged metal parts.

High-end bicycles indeed have tight tolerances. But consider the ill-fated Challenger launch stack. The solid rocket motor is 12 feet across. Each segment casing is a single milled steel part weighing several thousand pounds. The tangs and clevises are milled to allow only 0.035 inch clearance when mated. The gap that formed in the field joint, causing the exhaust gases to escape and destroy the vehicle, was on the order of 0.06 inch, meaning that the difference in that system between safe operations and disaster is about six sheets of copier paper -- out of 12 feet. This is what we mean by "aerospace tolerances."

 

[sts60]

...

Vehicle | Part Count
bicycle | 200
automobile | 2,500
Boeing 747 | 6,000,000

By one common measure of engineering complexity (part count) an airliner is thirty thousand times more complex than a bicycle. In fact, it takes 270,000 specialized tools alone to build an airliner...

Not to mention a few million lines of code for the later models like the 777.

 

[JayUtah]

Patrick1000/fattydash/DoctorTea...

Don't forget HighGain, the radar programmer in China.

Disregarding his bizarre reference to "absolute zero" - which is irrelevant to ICBMs...

I had hoped Patrick would address this, but clearly he will not. It shows how little he understands the problem.

First, an object in orbit or on a ballistic ICBM trajectory is not automatically at absolute zero. Sunlight will shine on it at some point during its flight. The lit side of the object will be hot while the shaded side will be cold. The exact temperatures will be dictated by the object's thermodynamic and heat-transfer properties.

Second, heat transfer is not instantaneous. An ICBM warhead bus spends very little time in space. With their missions only 18 minutes long, from launch to detonation, a warhead just doesn't have much time to cool down between boost and entry interface.

Third, aerodynamic heating isn't an issue only on re-entry. It occurs during boost, too. You can reach temperatures of 100-150 C on the nose fairing. So the hot potato arrives in space, pauses long enough to aim, then plunges back down through the atmosphere.

We don't test warheads and entry vehicles for cold because they don't get cold. All the design effort is on managing heat.

The effect of the reentry environment was studied in wind tunnels which generated various durations, speeds, and temperature ranges of atmospheric flow. This provided the necessary knowledge of the aerodynamic and thermal effects.

One of the earliest general models of weapon re-entry vehicle dynamics and thermal response was developed by NACA, the predecessor to NASA. Patrick wants to chastise NASA for being a "peaceful" agency, yet engaging in weapons research. In fact NASA naturally contributes to defense. It is not itself a military agency, as some assert, but that doesn't mean it is barred from doing research that has military (and perhaps even military-only) applications.

The same wind tunnels used to test re-entry vehicle casings in the 1950s were used to test Apollo heat shields. The heat shield design was borrowed from the ablative re-entry vehicle design.

The interplay of analysis and numerical modeling with physical testing - component, subsystem, aerothermodynamic, and, yes, flight, all of which were performed - was standard practice then just as it is now.

Indeed, and you have to practice as an engineer for years to get the hang of it. You can regurgigoogle facts, but you can't Google for understanding.

Seems to me what Patrick is describing in terms of finding a guide star is oddly similar to how he describes testing procedures for aerospace; as an all-up, one-shot, package deal. No iterative methods, no divide and conquer, no top-down; just solve the entire problem at the desired level in one shot.

I am NOT an engineer. I am in a technical field, though, and I'd never get anywhere if I tried to problem-solve like this.

Engineering is not just applied mechanics. It is a way of thinking. The decomposition nomuse talks about and the modeling sts60 talks about are techniques that derive from engineering-type thinking. The reason engineers succeed where handwaving pontification, such as that from Patrick, fails is precisely that we know how to find out what is strictly necessary, versus that which is merely believed to be necessary.

Certain aspects of engineering can be taught. Other aspects have to be learned by trial and error. Patrick always tries to make people solve harder problems than necessary, then assert that they're therefore impossible. That's a very layman thing to do.

 

[Loss Leader]

Patrick always tries to make people solve harder problems than necessary, then assert that they're therefore impossible. That's a very layman thing to do.

Well, that's unnecessarily harsh. Patrick is a layperson and Patrick badly misunderstands both engineering and logic. That doesn't mean that misunderstanding engineering and logic are characteristics of all laypeople or even the typical layperson.

If you meant that his manner of thinking is sufficient evidence that he is not an engineer, I certainly agree. If you meant that his manner of thinking is a necessary property of being a layperson then, as such a layperson, I take offense.

 

[JayUtah]

Well, that's unnecessarily harsh. Patrick is a layperson and Patrick badly misunderstands both engineering and logic. That doesn't mean that misunderstanding engineering and logic are characteristics of all laypeople or even the typical layperson.

If you meant that his manner of thinking is sufficient evidence that he is not an engineer, I certainly agree. If you meant that his manner of thinking is a necessary property of being a layperson then, as such a layperson, I take offense.

I've highlighted what I meant. No offense was intended.

One must be reckoned a layman with respect to some body of knowledge. Between a doctor and a clergyman, the former is an expert in medicine but a layman in theology, while the latter is a layman in medicine but an expert in theology. Therefore when I described Patrick as a layman I intended it with respect to engineering.

Patrick also misunderstands logic, but that is not part of my line of reasoning on this point.

Yes, Patrick's manner of thinking reveals that he is not an engineer. That was the point I was trying to make. The lay "common sense" approach to solving problems in engineering almost always makes the mistake of overcomplicating the problem and its candidate solutions.

Certain properties of engineering hypotheses such as coupling, systemic complexity, or criticality are more consciously considered by the engineer because he has been taught them and has often felt the pain of ignoring them. Hence an engineer's hypothesis (i.e., his design) quickly converges to one that maximizes the favorable properties and eliminates or mitigates the unfavorable ones.

Other complications include the assumption of requirements or constraints that are not strictly part of the problem. The engineer is accustomed to thinking carefully why something is part of his design, and to adopt a very literal -- almost austerely robotic -- view of the world. This is a different aspect of the systemic complexity discussion above, but one that Patrick is especially guilty of.

And most insidiously, the engineer understands that everything that's part of his design has intended effects and consequences, and unintended consequences and interactions. An engineer who wants to coat his spacecraft with delicate strips of aluminized Kapton for thermal reasons must accept the need to protect that coating throughout the manufacture, test, integration, and operation of the spacecraft. The understanding that everything is a tradeoff is characteristic of the engineer's approach. The layman, on the other hand, is wont to suggest something without fully considering the consequences in the overall design.

Further, the lay approach constructs a design using only a restrictive subset of knowledge, not the entire design vocabulary. And if that limited knowledge cannot provide a working solution, the impertinent layman will improperly declare the problem intractable. Fortunately not all laymen are impertinent. The conscientious layman will say, "I cannot figure out how this would be done; is there an expert who knows?"

Finally, the lay approach is not illogical per se, in my opinion. Even working from limited knowledge of what is possible, and according only to a common-sense notion of cause and effect, the layman may employ reasonably defensible inference in attempting to solve an engineering problem. It is, in fact, one of the principal theses of noted author Henry Petroski (cf. To Engineer Is Human) that engineering is at its core a deeply universal activity.

So when I said that something was "a very layman thing to do," it was not to cast aspersions on laymen at all. It was simply, and without value judgment, to observe that some certain approach reveals its originator to be a layman. When you see an engineering hypothesis overburdened with complexity, with non-existent requirements, and with certain other idiomatic errors, you know its originator lacks engineering training and expertise. That doesn't mean the hypothesis is itself badly illogical, or that its originator necessary suffers from some deep character flaw. He is simply not an expert in that particular field.

 

[nomuse]

Hrm. I suspect it is only true in a subset of engineering problems, but I have this experience of good solutions looking like obvious solutions. And from my end of it, the "obvious" solution that addresses the core problem so accurately is the end-result of an awful lot of work on my part trying to parameterize...actually, trying to find the correct parameters of the problem (solving the box the problem is in instead of getting fixated on the box). And of course stating and rejecting lots of less-optimal solutions until I arrive at the one that, in the end, looks like anyone could have walked up and said, "But that's the obvious thing to do!"

 

[sts60]

Don't forget HighGain, the radar programmer in China.

Yes, and a host of other sock-puppets on apollohoax and BAUT.

I had hoped Patrick would address this, but clearly he will not. It shows how little he understands the problem.

First, an object in orbit or on a ballistic ICBM trajectory is not automatically at absolute zero. Sunlight will shine on it at some point during its flight. The lit side of the object will be hot while the shaded side will be cold. The exact temperatures will be dictated by the object's thermodynamic and heat-transfer properties

Second, heat transfer is not instantaneous. An ICBM warhead bus spends very little time in space. With their missions only 18 minutes long, from launch to detonation, a warhead just doesn't have much time to cool down between boost and entry interface..

I wrestled a little with this before posting. I agree that "Absolute zero" was presumably a fumbling reference to the radiative heat sink of deep space, which is part of the thermal considerations for spacecraft, as are IR and albedo heating from the Earth and direct Sun heating. But, given the extremely short exoatmospheric life of an ICBM, these considerations are very minor in this case.

I had originally included explanatory text noting this, then just chucked it as too clunky for the post. It's a sufficiently good approximation to say that "absolute zero has nothing to do with ICBMs". That's an engineering perspective.

We do include that on the spacecraft projects on which I work because (ideally) they don't spend such a short time in space. (The last time one did, the PM gave us the tracking news from NORAD, and then we all adjourned to a nearby bar. There was already a boisterous group there that had all just been laid off from a nearby high-tech business. Misery loves company, but hey, at least we still had jobs.)

As Jay notes, timing is an issue. A deep-space probe has a few thermal environments to consider. First, there's the near-Earth environment mentioned above, which may last only hours but needs to be addressed. Once away from Earth, you have the simple early-mission environment, in which there is essentially no more heating from the Earth but you're still getting about 1400 W/m² form the Sun; the simple deep-space environment, where this heating decreases drastically. These phases can be considered steady-state conditions as things don't change over time the way they do in orbit around the Earth. If you go into orbit or land on a planet, things get complicated and time-dependent again.

But all these analyses depend on the mission profile, including what the vehicle is supposed to do. An ICBM is supposed to go somewhere fast and explode; it doesn't need to maintain delicate external instruments at a certain temperature range, and it doesn't need to preserve its innards for days or even hours. The temperature control demands due to the space environment are insignificant compared to those imposed by atmospheric flight.

Third, aerodynamic heating isn't an issue only on re-entry. It occurs during boost, too. You can reach temperatures of 100-150 C on the nose fairing. So the hot potato arrives in space, pauses long enough to aim, then plunges back down through the atmosphere.

The heating rates are very high on reentry because the vehicle starts reentry with all that speed, unlike launch. But nosetip materials are designed to manage the heating rates and aerodynamic stress long enough to preserve the payload.

We don't test warheads and entry vehicles for cold because they don't get cold. All the design effort is on managing heat.

Indeed. And when nosetip materials are applied to isotope heat sources, the heat management problem becomes even more interesting because there's a lot of heat constantly generated inside the material, and the fuel cladding needs to be kept within a "Goldilocks" range. A great deal of analysis, simulation, and aerothermodynamic testing has been done to ensure this occurs over a wide range of contingencies, from ascent-phase failure all the way to EGA flyby reentry. What has not been done is to take fueled heat sources and intentionally reenter them, because the risk/cost/benefits do not support doing so. (Note that each launch using these heat sources requires Presidential approval after two independent, mission-unique safety analyses; this was most recently done for MSL.)

 

[Robrob]

The fundamental point Robrob is that a bicycle is a much more sophisticated , much more complex machine than an airplane or rocket..Once you understand that, you are home free......

OK, are you having one on us?

 

[JayUtah]

I am a doc

Now that you seem to have rescinded this claim by saying that your doctor persona was merely an assumed identity to mislead and confound your critics, will you soon be conceding your claim regarding Borman's illness on Apollo 8.

If you will not concede it, do you have a new argument in favor of it?

 

[Patrick1000]

Here's a Neil Armstrong gaffe that proves Apollo inauthenticity.

On page 125 of David Whitehouse's book, ONE SMALL STEP(Quercus Publishing, London, 2009), Armstrong is quoted as saying that his concern about running out of fuel during his "lunar module landing" on 07/20/1969 was somewhat mitigated by his knowing that if he could get his speed and attitude stabilized, he could fall from a fairly good height "PERHAPS MAYBE 40 FEET OR MORE IN THE LOW LUNAR GRAVITY". Armstrong claimed the gear would absorb that much fall. As such, Armstrong claimed he wasn't as concerned as those back on earth, not as concerned about the gas running out problem.

Does Armstrong's claim make any sense? Well of course not. I'll show you why and then I will put the gaffe in a broader perspective.

The lunar lander's mass was 15,200 kg without the propellant. So it's earth weight was 33,440 lbs. From 40 feet up at 1/6 of the earth's gravity it would take 3.87 seconds for the Eagle to hit the surface of the moon were it to free fall. The kinetic energy the Eagle would possess were it to fall from 40 feet is given by the simple equation mass x gravity x height and in this case that would be 15,200kg X 9.81 m/s per s/6 x 12.192 meters = 302,996 joules.

So if we take Armstrong at his word, a 40 foot Eagle fall under lunar conditions would mean the 15,200 kg bird would strike the lunar surface after a 3.87 second fall at a velocity of 6.33 meters per second or equivalently 20.6 feet per second or equivalently 13.6 miles and hour. The Eagle's kinetic energy on impact would be 302,996 joules.

I'll translate that into more familiar terms. The average compact car weighs roughly 3000-4,500 lbs. I'll use the halfway point, 3,750 lbs(1704 kg) The Eagle weighs 33,440 lbs without "gas" so that's 8.92 times as much as the compact car. I'll show an equivalent earth based situation using the compact car as the falling object, equivalent in that at the time the compact hits the earth it will be carrying 302,996 joules of energy.

Here on earth the kinetic energy of a falling object will of course also be given by mass x gravity x height. One wants here the height of a compact car fall that will give a solution providing 302,996 joules of energy. 302,996 divided by 1704 divided by 9.8 = 18.14 meters or 59 feet. So if a compact car were to be dropped from 59 feet, it would take 3.48 seconds to hit the earth with the same kinetic energy as Neil Armstrong's Eagle falling from 40 feet on the moon. My compact car would be moving at 34 meters per second at the time of impact. That translates to 112 feet per second or 76 miles an hour.

So let's think about Armstrong's claim. He says that if he were to be able to control the Eagle's speed and attitude so that it simply dropped straight down, the thing could land on its legs and everything would be hunky dory.

Doesn't make any sense at all does it now? Put those lunar module legs on a compact car. Secure them any way you like. Run the car into a wall at 76 miles per hour. And, given Armstrong's scenario, what's the likelihood under those circumstances that the thing will hit with one and not 4 legs. A 3750 lb car moving at 76 miles an hour running an Apollo lunar module leg into a solid piece of rock.

So Armstrong is way wrong here, either that or the dude is stranded on the moon with Aldrin.

What's going on? Well it is just like when Collins says at the Apollo 11 post flight press conference that he couldn't recall seeing any stars when they traveled to the moon as the moon was eclipsing the sun. Same thing here. It is a ridiculous statement by Armstrong. He rarely messed up, but this here indeed was one of those rare screw ups. This of course is why Armstrong did not give interviews as a rule, did not write books, did not answer questions. The more of that stuff you do, the more this kind of stuff happens.

40 foot drop of a lunar module could easily break the leg on a lunar module and strand you with Aldrin.