|
|
|
filthy
SFN Die Hard
USA
14408 Posts |
 Posted - 09/05/2005 : 05:01:41 [Permalink]
|
FOOL, n. A person who pervades the domain of intellectual speculation and diffuses himself through the channels of moral activity. He is omnific, omniform, omnipercipient, omniscience, omnipotent. He it was who invented letters, printing, the railroad, the steamboat, the telegraph, the platitude and the circle of the sciences. He created patriotism and taught the nations war — founded theology, philosophy, law, medicine and Chicago. He established monarchical and republican government. He is from everlasting to everlasting — such as creation's dawn beheld he fooleth now. In the morning of time he sang upon primitive hills, and in the noonday of existence headed the procession of being. His grandmotherly hand was warmly tucked-in the set sun of civilization, and in the twilight he prepares Man's evening meal of milk-and-morality and turns down the covers of the universal grave. And after the rest of us shall have retired for the night of eternal oblivion he will sit up to write a history of human civilization. -- Ambrose Bierce
|
"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist! 
|
 |
|
|
bigbrain
BANNED
409 Posts |
Posted - 09/05/2005 : 10:21:02 [Permalink]
|
Dear friend sts60, at which velocity did it reenter in our atmosphere? Do please some calculations of the temperature due to impact.
Thank you 
|
"Obsequium amicos, veritas odium parit" (Flattery gets friends, truth hatred)
Publius Terentius Afer, "Terence", Roman dramatist
|
|
|
|
bigbrain
BANNED
409 Posts |
Posted - 09/05/2005 : 12:33:05 [Permalink]
|
Waiting for sts60 answer, look at this
http://seds.lpl.arizona.edu/nineplanets/nineplanets/meteorites.html
"The average meteoroid enters the atmosphere at between 10 and 70 km/sec. But all but the very largest are quickly decelerated to a few hundred km/hour by atmospheric friction and hit the Earth's surface with very little fanfare. However meteoroids larger than a few hundred tons are slowed very little; only these large (and fortunately rare) ones make craters".
Conclusion?
That ridiculous bath-tub would have burnt because of atmospheric friction, Aldrin and Armstrong would have become roast chickens.
Dear Filthy, I'm not a fool as you are not an idiot
|
"Obsequium amicos, veritas odium parit" (Flattery gets friends, truth hatred)
Publius Terentius Afer, "Terence", Roman dramatist
|
|
|
|
Dry_vby
Skeptic Friend
Australia
249 Posts |
Posted - 09/05/2005 : 18:12:11 [Permalink]
|
"The average meteoroid enters the atmosphere at between 10 and 70 km/sec. But all but the very largest are quickly decelerated to a few hundred km/hour by atmospheric friction and hit the Earth's surface with very little fanfare. However meteoroids larger than a few hundred tons are slowed very little; only these large (and fortunately rare) ones make craters".
Did you have yor helper monkey read this out to you?
You are argueing against yourself.
Read it again, goofball
".....all but the very largest are quickly decelerated to a few hundred km/hour by atmospheric friction and hit the Earth's surface with very little fanfare."
bigbozo
|
"I'll go along with the charade
Until I can think my way out.
I know it was all a big joke
Whatever it was about."
Bob Dylan
|
|
|
|
Dr. Mabuse
Septic Fiend
Sweden
9687 Posts |
Posted - 09/05/2005 : 18:59:50 [Permalink]
|
quote:
Originally posted by filthy
A sneer at NASA
Entirely CAPITALIZED
From a padded cell.
Brilliaint!
Please re-post it in the Haiku-thread. |
Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
Dr. Mabuse whisper.mp3
"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse
Support American Troops in Iraq:
Send them unarmed civilians for target practice..
Collateralmurder. |
|
|
|
pfretzschner
Skeptic Friend
USA
67 Posts |
Posted - 09/05/2005 : 21:40:22 [Permalink]
|
quote:
A sneer at NASA
Entirely CAPITALIZED
From a padded cell.
Filthy, you kick ass, man.
|
| Edited by - pfretzschner on 09/05/2005 21:43:03 |
|
|
|
bigbrain
BANNED
409 Posts |
Posted - 09/05/2005 : 23:02:49 [Permalink]
|
sts60 hasn't answered.
Then sts60 with his calculations HAS FOUND THAT THE TEMPERATURE OF THAT BATH-TUB INCREASED UP TO 5000 - 10000 °C
Aldrin and Armstrong would have burned to death.
 |
"Obsequium amicos, veritas odium parit" (Flattery gets friends, truth hatred)
Publius Terentius Afer, "Terence", Roman dramatist
|
|
|
|
furshur
SFN Regular
USA
1536 Posts |
|
|
Valiant Dancer
Forum Goalie
USA
4826 Posts |
Posted - 09/06/2005 : 07:55:00 [Permalink]
|
quote:
Originally posted by zaphod beeblebrox
quote:
Originally posted by bigbrain
---------------------------------------------------------------------
Listen to me carefully: Bush has said Americans will go again to the moon in ten or fifteen years.
But it would be enough to dust that old crock of Lunar Module if you want to go again to the moon.
Or it could just be that there aren't any left and it be far to dangerous to use a forty year old spacecraft.
I saw one in the Smithsonian Air and space Museum. But since it's 40, I'd think they'd prefer a newer design. |
Cthulhu/Asmodeus when you're tired of voting for the lesser of two evils
Brother Cutlass of Reasoned Discussion |
|
|
|
sts60
Skeptic Friend
141 Posts |
Posted - 09/06/2005 : 09:47:07 [Permalink]
|
I saw one in the Smithsonian Air and space Museum. But since it's 40, I'd think they'd prefer a newer design.
You're right.
People with no experience in technical projects often assume that you can just pick up and dust off old designs and crank out a new one. Of course, it doesn't work that way; no set of drawings can replace the live know-how of smart and dedicated people who were working on the project. As an engineer, I see and deal with this sort of thing frequently. Technology ages. Suppliers get bought by other companies or go out of business; documentation is lost, forgotten, or warehoused; tooling is scrapped; computer equipment used for design, processing and data storage becomes rapidly obsolete.
Most of all, the team that solved the problems and built the system is disbanded, and you cannot just put together a new one and expect that they can pick up where the original team left off. In many cases, even if they had a step-by-step recipe, the original ingredients would all need to be replaced by modern equivalents, or need to be requalified; but the know-how and judgment which cannot be translated easily to paper is dispersed, and certainly no longer fresh in people's minds.
The solution is not to attempt to refly a decades-old system, but to build on the knowldege and techniques developed for it to build a new and appropriate system. I emphasize "appropriate" because the current plans for returning to the Moon (at least for the U.S.) don't involve a brief stay for two people, but long-term development and habitation. There is, therefore, no future use for an Apollo LM, even if there was a showroom full of 1972 models in mint condition.
What there is a use for, again, is the experience and techniques developed during the past half-century of spaceflight. There is a reason, for instance, that every nation (U.S., USSR/Russia, and China) to have launched humans into space has used the classic blunt-body "space capsule" design. It goes back to the 1950s, when everyone was trying to figure out how to get a streamlined, pointed vehicle through the heat of reentry. Originally conceived at Ames Research Center, the blunt lifting body was developed by NASA's Max Faget into the classic rounded cone shape familiar from Mercury, Gemini, Apollo, Soyuz, and recently the Chinese Shenzhou.
I have a lithograph on my wall of the original Mercury capsule concept drawing signed by C.C. Johnson, the design engineer who drafted it in 1958. Why do the capsules flown today by the Russians and Chinese look like it? Why do designs for future manned systems look like it? Because it works.
Everybody used to think that spaceships had to be needle-nosed to go through the atmosphere. It turned out that what was great for minimizing drag on the way up was terrible for minimizing heat transfer into the vehicle on the way down. The blunt shape of a space capsule pushes the shock wave out in front of the vehicle, keeping ultra-high speed air away from direct contact. A layer of hot but slow-moving plasma actually acts as a sort of bearing or insulator, and what you get is heat transferred to the vehicle by radiation rather than by friction. But the vehicle can radiate heat back out, too - the efficiency of this goes up as the fourth power of the temperature. The ablative heat shields on capsules are designed to remove heat this way as well as by sacrificing themselves a little bit at a time. (It's an easier problem than the non-ablative system used by the Shuttle.) Again, it's why everybody uses the same basic design. It's also why relatively small meteors, many moving much faster than the Apollo CM, can survive the trip; they are their own blunt-body, ablative "reentry system". |
|
|
|
ktesibios
SFN Regular
USA
505 Posts |
Posted - 09/06/2005 : 11:24:31 [Permalink]
|
sts60, I recall reading somewhere or another that at the speed of a re-entering spacecraft the most important cause of heating isn't atmospheric friction (as in the case of high-speed aircraft) but the compression of the air in front of it. Is that correct?
Also, I'm tempted to guess that in designing an ablative heat shield you would want the ablative material to have as high a specific heat as possible, to maximize the amount of thermal energy carried away by each little bit of shield as it ablates, and to make the thermal resistance between the shield and the capsule as high as possible to minimize heat transfer from the hot part of the shield to the capsule. Am I close or cockeyed there?  |
"The Republican agenda is to turn the United States into a third-world shithole." -P.Z.Myers |
| Edited by - ktesibios on 09/06/2005 11:25:36 |
|
|
|
sts60
Skeptic Friend
141 Posts |
Posted - 09/06/2005 : 12:51:21 [Permalink]
|
Spot on. The shock wave in front of a blunt reentry body keeps the fast-moving gases of the surface of the vehicle, preventing friction. The very hot gas inside the shock boundary heats the vehicle through radiation and convection, but the vehicle also radiates back.
You're also there on ablative shielding, not that I am any sort of expert. Not just density is important, though; in addition to the insulative qualities, which rely on more than just heat capacity, there is also the property of what the material turns into when heated. The charring of a heat shield not only generates stuff which carries away heat, but reduces heat transfer by convection of the hot gases.
Light materials, such as cork and wood - that's right - have even been used in heat shields. So have heavy, highly advanced materials such as graphitized carbon, such as that used in the heat source aeroshells for Cassini, Galileo, and the upcoming Pluto flyby mission. The choice of a heat shield, of course, all depends on your application. |
|
|
|
Dr. Mabuse
Septic Fiend
Sweden
9687 Posts |
Posted - 09/06/2005 : 13:00:49 [Permalink]
|
quote:
Originally posted by sts60
The blunt shape of a space capsule pushes the shock wave out in front of the vehicle, keeping ultra-high speed air away from direct contact. A layer of hot but slow-moving plasma actually acts as a sort of bearing or insulator, and what you get is heat transferred to the vehicle by radiation rather than by friction.
A home-in-the-kitchen experiment:
1) heat the stove plate to near reddish glow or an (preferably iron) frying-pan.
2) drop some water on the plate and see how very hot plate keeps the droplet suspended on a cushion of steam, not consuming the drop as quickly as if the plate had been cool enough to allow the water to boil away instantly without the insulating steam. |
Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
Dr. Mabuse whisper.mp3
"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse
Support American Troops in Iraq:
Send them unarmed civilians for target practice..
Collateralmurder. |
|
|
|
bigbrain
BANNED
409 Posts |
Posted - 09/06/2005 : 13:03:36 [Permalink]
|
---------------------------------------------------------------------
Originally posted by furshur
http://www.bookrags.com/sciences/astronomy/heat-shields-spsc-03.html
---------------------------------------------------------------------
"... while the later Apollo capsules had shields made of phenolic epoxy resin, a form of plastic. Apollo heat shields were nearly 7 centimeters (2.7 inches) thick and weighed 1,360 kilograms (3,000 pounds)...
HA,HA,HA
NASA's buffoons used PLASTIC to protect Apollo capsules...
7 CENTIMETERS THICK
Cripes, slowly I'm knowing a mountain of craps AND YOU SAY: YES, PLASTIC IS VERY HEAT RESISTING, ALL PEOPLE KNOW THIS.
AMONG THE OTHERS, THIS IS THE VERY MUCH MORE BIGGEST IMBECILLAGGINE I HAVE NEVER HEARD.
IF YOU THINK THAT PLASTIC CAN PROTECT A CAPSULE THAT RUNS AT 40,000 KILOMETERS PER HOUR IN ITS IMPACT WITH ATMOSPHERE, THEN YOU ARE IDIOTS WITHOUT ANY HOPE
|
"Obsequium amicos, veritas odium parit" (Flattery gets friends, truth hatred)
Publius Terentius Afer, "Terence", Roman dramatist
|
|
|
|
Valiant Dancer
Forum Goalie
USA
4826 Posts |
Posted - 09/06/2005 : 14:37:39 [Permalink]
|
quote:
Originally posted by bigbrain
---------------------------------------------------------------------
Originally posted by furshur
http://www.bookrags.com/sciences/astronomy/heat-shields-spsc-03.html
---------------------------------------------------------------------
"... while the later Apollo capsules had shields made of phenolic epoxy resin, a form of plastic. Apollo heat shields were nearly 7 centimeters (2.7 inches) thick and weighed 1,360 kilograms (3,000 pounds)...
HA,HA,HA
NASA's buffoons used PLASTIC to protect Apollo capsules...
7 CENTIMETERS THICK
Cripes, slowly I'm knowing a mountain of craps AND YOU SAY: YES, PLASTIC IS VERY HEAT RESISTING, ALL PEOPLE KNOW THIS.
AMONG THE OTHERS, THIS IS THE VERY MUCH MORE BIGGEST IMBECILLAGGINE I HAVE NEVER HEARD.
IF YOU THINK THAT PLASTIC CAN PROTECT A CAPSULE THAT RUNS AT 40,000 KILOMETERS PER HOUR IN ITS IMPACT WITH ATMOSPHERE, THEN YOU ARE IDIOTS WITHOUT ANY HOPE
Evidentially you are ignorant of the capabilities of plastics.
http://www.sdplastics.com/plastics.html
It's what's mixed in with plastics which can change the particular characteristics of the finished product. |
Cthulhu/Asmodeus when you're tired of voting for the lesser of two evils
Brother Cutlass of Reasoned Discussion |
|
|
 |
|
|
|
Topic Locked
