ApolloHoax.net
Apollo Discussions => The Reality of Apollo => Topic started by: mako88sb on February 12, 2015, 02:11:25 PM
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I finally managed to track down a copy of Virtual LEM a while ago for a reasonable price. One thing mentioned in it is the 400 to 1 ratio for how many lbs of fuel required to land 1 lb on the moon and return it back to Earth. I believe I also read the same in Tom Kelly's book but I can't seem to locate it right now. Anyway, I've been wondering if this ratio has been improved upon over the years seeing as what I can make sense about rocket engines, they have improved in efficiency much like everything else nowadays. I imagine the use of SRB's probably helps as well. I'm sure there's not a clear cut answer as it all depends on the different configurations but which one would improve upon the 400 to 1 ratio the most?
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Any maneuver that one needs to perform on a space mission requires a certain change in velocity, called ΔV ("delta vee"). To complete a mission you need to add up all the ΔV to produce a ΔV budget. For instance, the ΔV budget for Apollo looked something like this (rough numbers):
Ascent to LEO = 9000 m/s
Tranlunar injection = 3200 m/s
Lunar orbit insertion = 900 m/s
Lunar descent = 2100 m/s
Lunar ascent = 1900 m/s
Transearth injection = 1000 m/s
There's not a lot that technology can do to change the ΔV budget, so it's just a matter of how the ΔV can be produced. There's really only two ways that I can see to do this: (1) use more efficient staging, or (2) use more efficient propellants/engines. As far as staging goes, Apollo was pretty efficient - this was the purpose of adopting the lunar orbit rendezvous method. There might be some ways to squeeze a little more efficiency out of it, but I suspect those improvements would be small. That leaves us with propellants/engines.
The Saturn V was pretty efficient as far as propellant went - it used LOX/RP-1 in the first stage and LOX/LH2 in the upper stages. It is, however, possible to use more efficient engines. Both the F-1 and J-2 where open cycle engines and, therefore, had lower specific impulse than is possible with closed cycle engines (i.e. staged combustion). Although closed cycle is more efficient, it is also more complicated and expensive. There was at one time talk of adapting the space shuttle main engines (LOX/LH2 staged combustion) for use in future heavy launch vehicles, but I'm not certain of the current status of that. I think the plan was dropped because of the cost, instead favoring an upgraded version of the J-2. Staged combustion has never been used on anything approaching the size of the F-1, so we'd be getting into uncharted territory. Future heavy launchers are likely to make extensive use of SRBs, which are powerful and relatively cheap, but have lower specific impulse than LOX/RP-1.
The Apollo spacecraft itself used hypergolic propellants, which aren't especially efficient in terms of specific impulse. Back when the Constellation project was being considered, the plan was to use LOX/LH2 in the lunar lander. The Orion service module would use hypergols just as Apollo did, though LOX/methane was considered at one time. The staging was also going to be modified. The lander's descent stage would be used to perform lunar orbit insertion rather than the service module. The only major maneuver that the service module would perform was transearth injection. I don't remember if the lander was to use LOX/LH2 in both the descent and ascent stages or just the descent stage. Regardless, this meant that somewhere between 3 km/s and 5 km/s ΔV would be switched from low-efficiency hypergols to high-efficiency LOX/LH2. This would certainly lower the amount of propellant needed to produce the required ΔV.
I don't know exactly how the 400:1 ratio was derived (see below), but there are certainly some things that can be done with propellants and engines to be more fuel-efficient than Apollo. However, with current technology, I think the improvements would be marginally small.
(ETA 1)
The entire Apollo-Saturn vehicle contained about 2700 metric tons of propellant, thus 1/400th of that is 6.75 t. The total mass recovered at splashdown was no more than 5.5 t, which is closer to a 500:1 ratio. More importantly, the entire 5.5 t did not "land on the moon". The only portion of that to have actually been on the lunar surface was two astronauts, the lunar samples, and some other odds and ends. Probably not more than about 300 kg made its way from the lunar surface back to Earth, which is more like a 9000:1 ratio.
(ETA 2)
OK, I just read the quote from Virtual LM and is says that "the fuel-to-payload ratio was 400 to 1, meaning that for every pound of payload required for the trip to and from the Moon it would require some 400 pounds of fuel to get the job done." The quote doesn't specifically mention landing on the moon and is non-specific at to exactly what payload is. If we're talking about something like an Apollo 8 mission, then 400:1 sounds about right.
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Switching from hypergols to cryos has some problems too - larger tanks needed since the fuel is less dense - and the need for an ignition system.
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Thanks for the help guys. Much appreciated. Lots of info that I'm not up to speed on but should make for interesting reading when I get home from work tonight. Bob, the last bit you mention in your edit, is quite an eye opener.
Just seen your second edit. I wish I had Kelly's book handy because he explained it better if I recall right. It's been awhile since I read it though so maybe I'm off about that to.
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Bob, the last bit you mention in your edit, is quite an eye opener.
I have to agree. I used to do Educational Outreach visits a long time ago. I was asked to help with a rocket building session so took in my model of the Saturn. I explained to the kids thay only the Command Module came back to Earth (OK, that's not quite the truth in the strictest sense) (http://www.collectspace.com/news/news-032013a.html). It amazed the kids as I took the model apart to demostrate each part of the missions, finally finishing with the CM sat next to all the other parts.
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Switching from hypergols to cryos has some problems too - larger tanks needed since the fuel is less dense - and the need for an ignition system.
Yes, I was going to mention that but it was starting to get to be a bit too much for one post. A pressure-fed hypergolic system is relatively simple, compact, and reliable. Sometimes that is more important than a high specific impulse. I think much of it depends on how much ΔV is needed. For instance, if all one needs is 1000 m/s, then that can be achieved using hypergols with a mass ratio of about 1.4, which isn't all that bad. In that case I would favor using tried and true hypergols. On the other hand, when we need a much higher ΔV and a large mass ratio, it becomes more advantageous to use more efficient propellants.
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Just seen your second edit. I wish I had Kelly's book handy because he explained it better if I recall right. It's been awhile since I read it though so maybe I'm off about that to.
I bought Tom Kelly's book but I still haven't had the chance to read it. I certainly plan to get to it.
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It amazed the kids as I took the model apart to demostrate each part of the missions, finally finishing with the CM sat next to all the other parts.
It can sometimes seem incomprehensible that one F-1 engine could be considerably larger and heavier than the CM.
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It can sometimes seem incomprehensible that one F-1 engine could be considerably larger and heavier than the CM.
That feeling goes away when you take apart the turbopump or try to lift the injector plate.
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There haven't been any major breakthroughs in chemical rockets since Apollo but there certainly have been in avionics. The Saturn's guidance system, the IU, was about 2 tonnes. Since it sat on the S-IVB, those two tonnes came directly out of its lunar payload capacity. Today's guidance systems can be vastly smaller and lighter.
The avionics on the CSM and LM were also 1960s technology, of course, and they could be much smaller, lighter and less power-hungry today. Lower power also means the electrical power system could be lighter and smaller. Solar arrays can replace fuel cells as the primary power source, as they will on Orion. All these weight savings can be applied to more useful things.
A lot of the mass in an Apollo/Saturn stack was structure, and materials have also improved a fair bit since the 1960s. It might also be possible to redesign the stack to reduce the amount of structure needed, or to get rid of it as soon as possible. For example, the SLA that enclosed the LM was another 1200 kg that came directly out of the Saturn's useful lunar payload. The counterpart on modern launchers is the payload shroud typically dropped shortly after staging so its dead weight need not be carried all the way to orbit.
There are also system-level approaches, particularly multiple launches, to reduce the total amount of mass and fuel that need to be launched. Equipment and supplies could be sent ahead of a crew on an unmanned launch vehicle taking a slow but energy-efficient route to the moon via a Lagrange point. It would not need a launch escape system or fly a sub-optimal trajectory to maximize the chances of one working.
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Didn't the SLA carry the CSM? That's 40+ tonnes you need to carry at 4+ G.
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Yes, and that's why it had to be carried through TLI. The Apollo/Saturn stack is probably about as good a design as there is for a single launch using the LOR mission mode.
I gave the SLA as an example of how a different mission mode might eliminate some of the structural overhead. E.g., if the LM and CM were launched separately and joined in earth orbit, the shroud protecting the LM could be dropped earlier in the ascent. It would also allow the use of smaller launch vehicles that already exist instead of developing a new, large one that might have no other uses.
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Conversely, the thin-shelled truncated cone is still the structural basis of about half the available payload adapters for the Delta family. It's stronger than it looks.
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It seems there is no such thing as a "quick question about rocket engines" !!
Just looking through some of the information in this thread, such as the massive size of the F1 engines, and the complexity of spacecraft design and engineering, brings home something I feel is really important to keep in mind about the Apollo hoax theories and those who believe them. No matter what particular angle or aspect they are coming from, whether it is shadows on photos, van Allen belts, no stars in the lunar sky, etc, their whole expostulation boils down to one, gigantic Argument from Incredulity. They are, simply put, completely unable to understand, conceive of or imagine how it was possible to send people to walk on the Moon and return them to the Earth. Therefore they conclude that it cannot have happened. All evidence to the contrary is either handwaved away or dismissed as shillspeak. They would rather invent or believe in a massive, extremely complex, ongoing and ever expanding conspiracy to explain what they are either incapable of understanding or unwilling to try understanding.
To some extent, this makes me feel somewhat sorry for them.
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Exactly my observation too.
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My thoughts too. One of the reasons I like this forum is that I get to read about real engineering from real engineers. I often have questions but never ask as I feel slightly dumb, so just pick up snippets here and there. The utter scale of Apollo, not just the Saturn V, is mind blowing.
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Just seen your second edit. I wish I had Kelly's book handy because he explained it better if I recall right. It's been awhile since I read it though so maybe I'm off about that to.
I bought Tom Kelly's book but I still haven't had the chance to read it. I certainly plan to get to it.
I was only familiar with how the design of the LEM evolved from watching the Spider episode of FTETTM which I found fascinating. Some of the problems that came up are of course shown in that episode but reading the "Problems, Problems" chapter of Tom Kelly's book really showed the caliber of the people involved with the project. For example, one of the titanium tanks failed during testing and trying to determine why it happened proved to be very difficult and concerning. They were able to figure out eventually that the pads used to prep the titanium surface prior to welding were pretty costly so they decided to re-use them after a thorough washing. However, there was enough residual detergent left from washing that it actually had an adverse affect on the surface being prepped which led to the failure. Just one example of the challenges they had to overcome.
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They were able to figure out eventually that the pads used to prep the titanium surface prior to welding were pretty costly so they decided to re-use them after a thorough washing. However, there was enough residual detergent left from washing that it actually had an adverse affect on the surface being prepped which led to the failure. Just one example of the challenges they had to overcome.
These are the snippets of information that make Apollo so enjoyable to read about, and they make me think how can anyone believe there was a hoax? You can't make this stuff up.
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Just seen your second edit. I wish I had Kelly's book handy because he explained it better if I recall right. It's been awhile since I read it though so maybe I'm off about that to.
I bought Tom Kelly's book but I still haven't had the chance to read it. I certainly plan to get to it.
I was only familiar with how the design of the LEM evolved from watching the Spider episode of FTETTM which I found fascinating. Some of the problems that came up are of course shown in that episode but reading the "Problems, Problems" chapter of Tom Kelly's book really showed the caliber of the people involved with the project. For example, one of the titanium tanks failed during testing and trying to determine why it happened proved to be very difficult and concerning. They were able to figure out eventually that the pads used to prep the titanium surface prior to welding were pretty costly so they decided to re-use them after a thorough washing. However, there was enough residual detergent left from washing that it actually had an adverse affect on the surface being prepped which led to the failure. Just one example of the challenges they had to overcome.
And that brings up an interesting issue.
Titanium manufacture in the 1960's was nowhere near as good as it is today. There was potential for defects in titanium that could, and in fact did lead to structural failure in high stress components. In the famous "Sioux City Fireball", a DC10 crashed after it lost all three hydraulic systems when the No 2 (tail) engine exploded. This was caused when the titanium fan-disk in the No 2 (tail) engine flew apart, severing all three hydraulic lines at a point where they came close together near the horizontal stabiliser.
The root cause of the fan-disk failure was almost undetectable micro-fractures caused by microscopic oxygen and nitrogen bubbles which were left in the titanium when it was manufactured. Admittedly, the DC10 scenario was also caused by many years of fatigue, but I image the stresses and strains on the components in a Saturn V are far greater then those normally encountered on a passenger aircraft.
AIUI this accident led to a change in the titanium manufacturing process for aerospace applications. It is now remelted several times in a vacuum to draw out any gasses within.
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Reading about the injector for the F1-engine - it was apparently made from copper. Was that to utilize the heat conductive properties in order to avoid uneven heating and possibly warping of the injector? A higher-melting metal would be the layman's choice, but then there's the liquid oxygen cooling it . . .
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I often have questions but never ask as I feel slightly dumb
I don't believe anyone here would make the mistake of thinking you dumb, Luke.
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I don't believe anyone here would make the mistake of thinking you dumb, Luke.
Thanks, although I was not fishing for compliments. There are people here who are far more versed in Apollo and their understanding leaves me in awe (no connection to that awe :))).
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I don't believe anyone here would make the mistake of thinking you dumb, Luke.
Thanks, although I was not fishing for compliments. There are people here who are far more versed in Apollo and their understanding leaves me in awe (no connection to that awe :))).
The difference is that most people here know what they DON'T know - meaning they understand the limitations of their own specialty.
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One of the great things about this forum is that we've got people knowledgeable in so many disciplines. If I encountered an HB away from this forum, I'm confident that I could hold my own in a debate on almost any topic. But when I'm here I know when to shut up and let the real experts handle things. When it comes to things like photography, optics, video, and communications, I know that I'm way outclassed by people like Jay, Dwight and ka9q. Over the years I've learned to be more patient and to wait for my opportunities to contribute something of value to the discussion.
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The root cause of the fan-disk failure was almost undetectable micro-fractures caused by microscopic oxygen and nitrogen bubbles which were left in the titanium when it was manufactured. Admittedly, the DC10 scenario was also caused by many years of fatigue, but I image the stresses and strains on the components in a Saturn V are far greater then those normally encountered on a passenger aircraft.
AIUI this accident led to a change in the titanium manufacturing process for aerospace applications. It is now remelted several times in a vacuum to draw out any gasses within.
This brings back memories.
For turbine discs the critical size of HID (High Interstitial Dislocation) was undetectable during the manufacturing process, so only metal that passed through the procedures faultlessly wound up in them. Any deviations in melting or handling meant it was downgraded to less demanding final uses.
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When it comes to things like photography, optics, video, and communications, I know that I'm way outclassed by people like Jay, Dwight and ka9q.
That's how I feel. When I first joined the hoax debate I made a conscious decision not to try and become a jack of all trades, but chose areas where I knew I could develop my understanding based on my experience and own credentials. That decision was largely based on reading these boards and seeing the writing of others. I would never try to emulate Jay, sts60, ka9q, Dwight and many others. They've been there, done it and worn the T-shirt and have years of experience that I could never gain.
Over the years I've learned to be more patient and to wait for my opportunities to contribute something of value to the discussion.
With fattydash and the lost Eagle I knew I could only play an extra, but with Adrian and Romulus I piped in more as (a) I spotted contradictions in their argument (b)I knew what I was talking about.
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(b) I knew what I was talking about.
That much is obvious, Luke.
I've always had to struggle with the confidence thing. It's true that I have an engineering degree, but that was in civil engineering. There is nothing in my formal education or work experience that qualifies me as a expert astronautics or rocket dynamics. Everything I've learned about those subjects has been self taught. I've got no one testing or grading me to provide the confirmation that I know what I'm doing. As such, I've always looked for ways to test myself. The best way I've found to do this is to take a real life example and see if my computations replicate the result. I've tested my techniques using a wide range of data, both American and Soviet, and have gotten excellent results. As my confidence grew, I started to test different aspects of Apollo. I've since computed the trajectories, simulated the launches/landings, and verified just about everything I could. All of my computations and simulations are spot on with the Apollo data. This leaves me with no reason to doubt my methods or Apollo's authenticity.
It is the self-test part that the conspiracists leave out. When they apply their rudimentary understanding of physics to Apollo and come up with contradictory results, they immediately claim that there's something wrong with Apollo. They never seem to consider that it's their computations and, more likely, their understanding that are wrong. When I get different results, the first thing I think is "what did I do wrong" and I set out to find my mistake. Real learning occurs when a person can recognize their mistakes, correct them, and not repeat them. Most conspiracists refuse to acknowledge their mistakes and refuse to accept correction. That is willful ignorance, and is the thing I find most frustrating when dealing with them.
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That is willful ignorance, and is the thing I find most frustrating when dealing with them.
Absolutely, and that is why I prefer to be patient when dealing with them. It would be hypocritical of me to take a position from which I know little about in an attempt to boost my own standing.
I did comment on a photo thread the other day, but I was shown to be wrong. I accepted my 'wrong' graciously. That's an important aspect of this small community, being prepared to be wrong and moving on, unlike them who will never back down.
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I accepted my 'wrong' graciously. That's an important aspect of this small community, being prepared to be wrong and moving on, unlike them who will never back down.
We're all fallible. Although making a mistake may sometimes make us feel dumb, it's just part of the learning process. When I struggle through a problem and have to resolve mistakes, I often feel I learned more than when I do everything right the first time. For instance, I can pull an equation out of a book, apply it to a problem, get the right answer, and I move on. However, if the equation doesn't give the answer I expected, then I have to start digging deeper. I might have to re-derive the equation to figure out how I misapplied it. I emerge with greater understanding than had the mistake not occurred.
A conspiracist's refusal to acknowledge and correct mistakes is one of the most telling signs of just how insincere they are. They portray themselves as truth seekers, but their actions show that they seek only one outcome.
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They were able to figure out eventually that the pads used to prep the titanium surface prior to welding were pretty costly so they decided to re-use them after a thorough washing. However, there was enough residual detergent left from washing that it actually had an adverse affect on the surface being prepped which led to the failure. Just one example of the challenges they had to overcome.
These are the snippets of information that make Apollo so enjoyable to read about, and they make me think how can anyone believe there was a hoax? You can't make this stuff up.
Yeah, I know what you mean. Every book I've read by/about the astronauts involved has some fascinating details that as you say, can't be made up. I've tried to encourage hoax believers to read some of these accounts but always get the "if I want to read science fiction I'll....yada yada yada". Oh well, their loss.
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Yeah, I know what you mean. Every book I've read by/about the astronauts involved has some fascinating details that as you say, can't be made up. I've tried to encourage hoax believers to read some of these accounts but always get the "if I want to read science fiction I'll....yada yada yada". Oh well, their loss.
I've recently read Moondust, and it it was a hoax Andrew Smith would have latched on to it immediately. I have never understood the CTs from three main perspectives
- Do you really think that the USA could have fooled the USSR, China, France, UK and a list of others during the height of the cold war?
- Do you really think that the USA could have fooled the world's scientific community?
- Do you really think that the USA could have fooled journalists for 46 years?
These woo-hoo warriors with their YouTube channels and websites claiming that they are going to blow the gaff on NASA make me smile. If there was any truth in the hoax they would have been beaten to the punch by a gaggle of journalists by now. Does this ever cross their mind?
I'd like to see them take the stance that the press are in on the secret too. So who exactly owns Fox then? Only the biggest media magnate on the planet, and his corporation had no issues producing the Moon Hoax Special.
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And that brings up an interesting issue.
Titanium manufacture in the 1960's was nowhere near as good as it is today. There was potential for defects in titanium that could, and in fact did lead to structural failure in high stress components. In the famous "Sioux City Fireball", a DC10 crashed after it lost all three hydraulic systems when the No 2 (tail) engine exploded. This was caused when the titanium fan-disk in the No 2 (tail) engine flew apart, severing all three hydraulic lines at a point where they came close together near the horizontal stabiliser.
The root cause of the fan-disk failure was almost undetectable micro-fractures caused by microscopic oxygen and nitrogen bubbles which were left in the titanium when it was manufactured. Admittedly, the DC10 scenario was also caused by many years of fatigue, but I image the stresses and strains on the components in a Saturn V are far greater then those normally encountered on a passenger aircraft.
AIUI this accident led to a change in the titanium manufacturing process for aerospace applications. It is now remelted several times in a vacuum to draw out any gasses within.
The Sioux City crash also raises another interesting comparison: crew co-ordination. The landing involved four people in the cockpit, all working together to *almost* pull off a safe landing.
After the event, safety investigators ran through the scenario in a DC-10 simulator with similar crews. In every case, they crashed well before getting to the runway threshold. No-one, it seemed, could reproduce the CRM that went on.
Perhaps the Sioux City crash was "faked"?
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Claims that various accidental and deliberate man-made disasters were faked "false flag" operations really cheese me off, and not just because they're even more utterly ludicrous than the Apollo hoax claims. They also insult and torment the friends, families and colleagues of the victims.
9/11 is of course the great grand-daddy of the modern alleged "false flag" operations, and more recently we have Newtown and Boston. But I wouldn't be surprised if someone really were to claim this about an airline accident. As I recall, at least one passenger who died in the Sioux City crash was a fellow employee at the time, though I did not know him personally.
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They also insult and torment the friends, families and colleagues of the victims.
My thoughts exactly, and those expressed by Astrobrant. I find Truthers deplorable, given that 2000 people died that day and many more in the follow on wars that ensued. While 9/11 was an event on US soil, and I felt utter heartbreak for the American people that day, it has brought nothing but misery to thousands of people across the globe.
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My thoughts exactly, and those expressed by Astrobrant. I find Truthers deplorable, given that 2000 people died that day and many more in the follow on wars that ensued. While 9/11 was an event on US soil, and I felt utter heartbreak for the American people that day, it has brought nothing but misery to thousands of people across the globe.
And that's what gets me especially about 9/11 "truthers". There is plenty to criticize in the Bush administration's response to 9/11. Many, myself included, believe much of it qualifies as a war crime to say nothing of an impeachable offense. You don't have to invent wild fantasies about drone airliners and built-in demolition explosives to feel this way; the actual, uncontested facts are enough.
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But I wouldn't be surprised if someone really were to claim this about an airline accident.
Not an accident, but the USSR shooting down Korean Air Lines Flight 902 was widely attributed to a conspiracy by the US. Making it a false flag type operation to the CTist by using the Korean flagged airliner for a US military operation. The day or so after the incident, some jackass I met in the Munich youth hostel had already determined this and went to great lengths to let me, and any other Americans in his considerable vocal reach, know all about how it was our personal fault the Soviet military was forced to kill these innocent people.
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Yeah, I know what you mean. Every book I've read by/about the astronauts involved has some fascinating details that as you say, can't be made up. I've tried to encourage hoax believers to read some of these accounts but always get the "if I want to read science fiction I'll....yada yada yada". Oh well, their loss.
I've recently read Moondust, and it it was a hoax Andrew Smith would have latched on to it immediately. I have never understood the CTs from three main perspectives
- Do you really think that the USA could have fooled the USSR, China, France, UK and a list of others during the height of the cold war?
- Do you really think that the USA could have fooled the world's scientific community?
- Do you really think that the USA could have fooled journalists for 46 years?
These woo-hoo warriors with their YouTube channels and websites claiming that they are going to blow the gaff on NASA make me smile. If there was any truth in the hoax they would have been beaten to the punch by a gaggle of journalists by now. Does this ever cross their mind?
I'd like to see them take the stance that the press are in on the secret too. So who exactly owns Fox then? Only the biggest media magnate on the planet, and his corporation had no issues producing the Moon Hoax Special.
It would presumably be explained as Part Of The Bigger Picture - something done to distract the masses while The Powers That Be Cement Their Position In Control. In other words, just another part of the NWO-Illuminati Grand Unified Conspiracy Theory.
The idea that a party appears to be on one side of a conflict but hidden or obscured evidence suggests it's on the other side would seem to be a staple for conspiracy theorists. If in doubt, just add another layer to the conspiracy (just think about Turbonium and his willingness to reinterpret the Cold War).
I wonder if these people think TV series like "La Femme Nikita", "Lost" and "Mad Dogs" are accurate representations of what life is really like - that nobody is who they really seem to be, and that some people have more masks beneath the one that others see (like Maria in "Mad Dogs", who is initially portrayed as a police detective, but revealed to be a corrupt drug-running cop, only to be finally revealed to be a CIA agent).
In other words, when a story doesn't make sense, many people would be tempted to say it isn't true, but these people are tempted to believe this lack of sense is evidence of infernally clever machinations behind a cover story.
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And that's what gets me especially about 9/11 "truthers". There is plenty to criticize in the Bush administration's response to 9/11. Many, myself included, believe much of it qualifies as a war crime to say nothing of an impeachable offense. You don't have to invent wild fantasies about drone airliners and built-in demolition explosives to feel this way; the actual, uncontested facts are enough.
Exactly, and Blair is culpable too. The man took my vote in 1997, but I didn't cast a vote for him after Iraq. 9/11 happened as reported. Without turning this thread into a 9/11 conspiracy/political discussion, what followed was an excuse for the neo-con hawks to sharpen their claws. I don't get the fantasy when all one needs to do is attack the ensuing policy. In any case, this has very little to do with rocket engines.
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Not an accident, but the USSR shooting down Korean Air Lines Flight 902 was widely attributed to a conspiracy by the US. Making it a false flag type operation to the CTist by using the Korean flagged airliner for a US military operation.
That would still not be a false flag operation as I understand the term. If KAL007 were shot down by a MiG bearing a hammer-and-sickle flag but flown by an American pilot, now that would be a false-flag operation.
I see the KAL007 shootdown just as I see the IranAir 655 shootdown by the US Navy: tragic accidents by hot-headed, trigger-happy and arguably incompetent commanders pushed on by irresponsible political leaders bent on waving their you-know-whats at the world.
Only pure luck kept this from happening during the Cuban Missile Crisis when the missiles and torpedoes were nuclear.
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It was "false flag" in the sense that the fault could be attributed to America for falsely using KAL's flag and civilian status as a cover for its own operations. Rather than in the sense you mention of an operation done under the cover of another's flag to directly to pin the blame on the other party, which is probably the more common use. Covert is another term for describing CTist's attribution for the hypothesized KAL "operation," but that can also mean doing it secretly without invoking another's flag as cover.
The key in the conspiracy world is the technique of developing a rationale through some "tale," whatever that may be, that allows blame to be pinned on the desired donkey. ;)
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There are also system-level approaches, particularly multiple launches, to reduce the total amount of mass and fuel that need to be launched. Equipment and supplies could be sent ahead of a crew on an unmanned launch vehicle taking a slow but energy-efficient route to the moon via a Lagrange point. It would not need a launch escape system or fly a sub-optimal trajectory to maximize the chances of one working.
Multiple launches don't save mass, the actually increase it overall. They do make the mass of each individual launch less.
Flying to the Moon via a liberation point also saves little, if any propellant.
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But I wouldn't be surprised if someone really were to claim this about an airline accident.
Not an accident, but the USSR shooting down Korean Air Lines Flight 902 was widely attributed to a conspiracy by the US. Making it a false flag type operation to the CTist by using the Korean flagged airliner for a US military operation. The day or so after the incident, some jackass I met in the Munich youth hostel had already determined this and went to great lengths to let me, and any other Americans in his considerable vocal reach, know all about how it was our personal fault the Soviet military was forced to kill these innocent people.
I heard one ex-USN person claim it was a set up by Iran - a plane loaded with dead people on a suicide mission.
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Wouldn't that have been Iran Air 655, shot down by USS Vincennes?
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Wouldn't that have been Iran Air 655, shot down by USS Vincennes?
Correct, I was a guest in his house, so I did not tell him he was an idiot. I just rolled my eyes.
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I heard one ex-USN person claim it was a set up by Iran - a plane loaded with dead people on a suicide mission.
They used that idea in an episode of Sherlock.
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I heard one ex-USN person claim it was a set up by Iran - a plane loaded with dead people on a suicide mission.
They used that idea in an episode of Sherlock.
And Star Trek DS9.
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What episode?
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Rules of Engagement (http://en.memory-alpha.org/wiki/Rules_of_Engagement_(episode))
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Multiple launches don't save mass, the actually increase it overall. They do make the mass of each individual launch less.
I'd like to see an analysis.
Flying to the Moon via a liberation point also saves little, if any propellant.
I can cite several spacecraft that did this specifically to save propellant. E.g., the two GRAIL spacecraft went into lunar orbit via the earth-sun L1 point. The cost was >3 months of transit time vs 3 days for Apollo. This kind of trajectory could be used to transfer bulk cargo to a lunar base while crews would use the more costly direct transfer. This is what I meant by reducing total launch mass.
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Rules of Engagement (http://en.memory-alpha.org/wiki/Rules_of_Engagement_(episode))
Tnx. Didn't remember that one.
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Wouldn't that have been Iran Air 655, shot down by USS Vincennes?
Correct, I was a guest in his house, so I did not tell him he was an idiot. I just rolled my eyes.
Well if it had happened more recently, he could just stand up and be proud, and declare that the United States has the right to kill anyone it deems a threat to national security, any time, under any circumstances.
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Multiple launches don't save mass, the actually increase it overall. They do make the mass of each individual launch less.
I'd like to see an analysis.
All other things being equal dry mass tends to go up linearly whereas wet mass geometrically. For the same final payload the overall mission mass will be greater.
Flying to the Moon via a liberation point also saves little, if any propellant.
I can cite several spacecraft that did this specifically to save propellant. E.g., the two GRAIL spacecraft went into lunar orbit via the earth-sun L1 point. The cost was >3 months of transit time vs 3 days for Apollo. This kind of trajectory could be used to transfer bulk cargo to a lunar base while crews would use the more costly direct transfer. This is what I meant by reducing total launch mass.
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Good luck with sending crews on trajectories to the Moon that take months rather than days. The only advantage of lagrange points in crewed missions is they offer the possibility of leaving communications relays for the lunar far side.
As you say, unmanned missions are different.
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All other things being equal dry mass tends to go up linearly whereas wet mass geometrically. For the same final payload the overall mission mass will be greater.
I don't understand. The Tsiolkovsky equation only deals with mass ratios, not absolute masses. I can see how some overhead mass might not scale linearly with size, e.g., electrical power, guidance and command systems, but these are now so light compared to structure and even rocket engines that I doubt they make much difference unless the launch vehicle is very small.
I'd think a bigger factor would be the Isp of the rocket engines themselves, with larger ones traditionally having better performance. But I don't know the scaling laws for the current state of the art.
Good luck with sending crews on trajectories to the Moon that take months rather than days. The only advantage of lagrange points in crewed missions is they offer the possibility of leaving communications relays for the lunar far side.
My whole point was that not all of the mass to support a crewed mission has to be sent with the crew. If you send the support equipment and fuel in advance, it can take its sweet time getting there by an energy-efficient trajectory and be waiting when you launch the crew on a fast, higher-energy path.
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All other things being equal dry mass tends to go up linearly whereas wet mass geometrically. For the same final payload the overall mission mass will be greater.
I don't understand. The Tsiolkovsky equation only deals with mass ratios, not absolute masses. I can see how some overhead mass might not scale linearly with size, e.g., electrical power, guidance and command systems, but these are now so light compared to structure and even rocket engines that I doubt they make much difference unless the launch vehicle is very small.
Simplifying somewhat you can consider mass budgets consist of three categories, fixed mass, linear mass, and geometrical mass items. Fixed mass items - comms, guidance, etc. are basically the same regardless of overall mass. As you say, these are very small in this day and age. However it is still more efficient (all things being equal) to provide just one set of these rather than two or more. Linear mass items are things like engines and tankage, the bigger they are more massive. Lastly geometric mass items are propellant. Double the dimensions of the tanks and you cube the volume. However the mass of the engines and tankage has not cubed, because larger volumes store more efficiently with fewer losses (even allowing for the need for stronger tanks.
I'd think a bigger factor would be the Isp of the rocket engines themselves, with larger ones traditionally having better performance. But I don't know the scaling laws for the current state of the art.
Indeed, which is why I said all things being equal.
Good luck with sending crews on trajectories to the Moon that take months rather than days. The only advantage of lagrange points in crewed missions is they offer the possibility of leaving communications relays for the lunar far side.
My whole point was that not all of the mass to support a crewed mission has to be sent with the crew. If you send the support equipment and fuel in advance, it can take its sweet time getting there by an energy-efficient trajectory and be waiting when you launch the crew on a fast, higher-energy path.
You can do that if you want, but if you do, it is better to send them direct to the lunar surface to wait for the crew to land. No station keeping propellant needed, no rendezvous or docking in orbit, even if contact is lost, they won'r be going anywhere.
IMHO of course!
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You can do that if you want, but if you do, it is better to send them direct to the lunar surface to wait for the crew to land. No station keeping propellant needed, no rendezvous or docking in orbit, even if contact is lost, they won'r be going anywhere.
Well yeah, you sent the bulk supplies and equipment to wherever you intend to send the crew.
I don't know if a direct ascent would be more efficient for landing on the moon. That would require overcoming lunar escape velocity (in reverse) as well as whatever orbital velocity you have left after leaving earth and climbing to the moon's orbit. If you take a slow, low energy route to lunar orbit via a libration point, then to land you only need get rid of lunar orbital velocity, which is roughly sqrt(2) that of lunar escape. The question is which route has the lower total delta V requirement; I don't know.