Apollo, Soyuz, Shenzhou and CEV

[gunsandrockets]

Before...<br /><br />"NASA extensively studied the 3 piece capsule design for Apollo and came to the conclusion that it provided a little extra room at the cost of a lot more weight, complications with abort modes, and unneeded redundancy. "<br /><br /><br /><br />And after asking for evidence...<br /><br />"I never said ... that the 3-piece design isn't roomier overall--it is, and that it doesn't result in a lighter DECENT [descent] module--it does."<br /><br /><br />Well which is it then? Is a multi-module design spacecraft lighter than or heavier than a single-module design? But that's a rhetorical question, we both know the answer. <br /><br />And it's why Mark Wade was right to criticise the CEV. Mark made the excellent point that the retro design of the CEV causes it to be overweight, and therefore the CEV requires an oversized shuttle-derived CLV to launch it. Whereas a more efficient and lighter CEV design could be launched with smaller launch vehicles, vehicles already in service such as the Atlas V.<br /><br />You are entitled to think that NASA made the best possible choice for the CEV just as I am entitled to think NASA made a wasteful and mediocre choice. But before you challenge other people's credibility again you may want to consider following your own advice. <br /><br />"I think in general people on this board need to let go of their pet ideas a little bit and stop dismissing out of hand any ideas that challenge their little reality bubbles."<br /><br /> <br /><br />

 

[tomnackid]

Well which is it then? Is a multi-module design spacecraft lighter than or heavier than a single-module design? But that's a rhetorical question, we both know the answer.<br />---------------------------------------------------------------------------------------<br />That's a silly question. Without defining everything from construction techniques to mission architecture there is no way to answer a generic question like that. Will the multi module design need a launch shroud? How big can a multi module design be before lifting the dead weight of the orbital module during an abort becomes dangerous or completely undoable? We can compare "paper spacecraft" from now until the end or time. The CEV is tasked with continuing the exploration of the moon. What spacecraft has ALREADY brought people to the surface of the moon and back? But then that's a rhetorical question, we both know the answer!<br /><br />Sorry I invaded your little bubble of reality. Let me try and make it up to you. Ok the Soyuz is the greatest spacecraft ever built and ever to be built. We shouldn't even bother to try and improve upon it. Every engineer who has ever worked with NASA should be shot or imprisoned. We should scrap the CEV/CLV right now and burn or delete every bit of data from Mercury, Gemini, Apollo and STS. From now on the universe (well LEO anyway) will be won three men at a time the way god and Korolev intended.<br /><br />Sounds stupid? Yes? Then what actually is your point? The Apollo design team had reasons for choosing the design they did--Faget quoted some of those reasons in the link I showed you. But I guess he must be lying or just an idiot or part of some vast conspiracy to build poorly designed spacecraft that yet somehow still accomplish their tasks. The Soviets had reasons for choosing the design they did (and have been stuck on LEO for 50 years). Griffin et al. have reasons for choosing the design they have. Do we have only one kind of aircraft? Do we have one kind of automobi

 

[gunsandrockets]

An Earth returning spacecraft, such as the Apollo capsule, which places the entire living space into the reentry capsule is much less mass efficient than a spacecraft, such as the Soyuz, which minimizes the size of the reentry capsule by placing as much as possible of the living space into a lightweight 'orbital module' or 'mission module'. By minimizing the size of the reentry capsule, the mass of the heatshield is reduced, the mass of parachutes is reduced and the mass of impact equipment is reduced. The overall mass advantage of the multi-module design increases in even greater proportion if a spacecraft must be larger such as the four/six man crewed CEV. <br /><br />Comparisons of the masses of actual flying spacecraft show the truth of this principle. The combined mass of the Soyuz spacecraft's 'descent module' and 'orbital module' is less than the mass of the Apollo 'command module', even though the Apollo only has about 2/3 of the living space of the Soyuz.<br /><br />For some reason you seem to believe a single module design is lighter, has safer aborts and is simpler. And you posted a reference to support this idea. But your reference only supports the notion of simplicity and not your other mistaken ideas. In fact since a single module system is heavier than a two module system, it is the LES of a single module system that must be more massive, not the other way around.<br /><br />The shape used for the reentry module, which you seem so hung up on, is irrelevant to the superiority of the two-module design. There is no reason why a two module design could not use a straight Apollo analog for the reentry module shape. A two module design doesn't have to use a Soyuz-type "headlight" shaped reentry module (even though the headlight shape is superior).<br /><br />In fact now that NASA has shown the final form of it's planned moon flight architecture, NASA's choice of an overgrown Apollo capsule is even more inexplicable. On a moon trip the crew will generall

 

[tomnackid]

I don't accept your non-apology. Your whole point seems to be shouting down anyone who dissents from the NASA holy writ. You certainly aren't convincing me to fall into lockstep. <br />-------------------------------------------------------------------------------------------<br />I make a real effort to be reasonable and not get personal or rude, but it gets very difficult with all of the Space.com amateur, adolescent, rocket boys mouthing off whenever their precious pet ideas get questioned. I have never "shouted down anyone" and I certainly don't consider NASA's plans "holy writ" unless you consider acknowledging reality to "falling into lockstep".<br /><br />As I said over and over there is no one best spacecraft. NASA made decisions based many, many factors. Things you seem either unwilling to accept or are ignorant of. For example:<br /><br />1) Apollo is the ONLY architecture to have taken men to the moon and bring them back. Why throw away mountains of data on the Apollo design just to have something new? So, what if it is heavier than it absolutely has to be. You still save money in R&D by not going off in a completely new direction. Do you want NASA t sit around for another 20 years pushing out paper spaceships? 20 years is probably optimistic. We DON'T have the money for a Apollo-style, "whatever it takes", crash program. More likely if metal isn't cut in the next year or so the program will be cancelled completely. That's the political and economic reality. <br /><br />2) The CEV is the ONLY spacecraft authorized to be built right now. It has to be a multi-role vehicle. Yes, I know the concept that. "A multi-role vehicle is one that isn't particularly good at anything." , but sometimes that is all you can get. It would be nice if we all could have sports cars for tooling around on the highway, trucks for hauling stuff, a nice big van for taking the kids on trips, 4x4s for snow and off road, and an RV for vacations, but most of us have to make do with one or

 

[gunsandrockets]

I had a feeling I was wasting my time replying to you. Your comprehension of what I wrote is about as accurate as what you think the Faget interview contained. I'm not going to spoonfeed you any more and waste more time repeating myself.

 

[tomnackid]

Whoo hoo! thank god! <br /><br />You could cut the arrogance with a knife around here.

 

[gunsandrockets]

"You could cut the arrogance with a knife around here."<br /><br />Now that's a stunningly ironic statement. And also showing a stunning lack of self-awareness. I see someone is bucking for the Dobbins miss congeniality award.

 

[tomnackid]

"I'm not going to spoonfeed you any more and waste more time repeating myself."<br />---------------------------------------------------------------------------------<br /><img src="/images/icons/frown.gif" /> Oh well. I knew it was too good to be true!

 

[CalliArcale]

All right, be nice, guys. If you can't carry on the conversation civilly, you may want to consider stepping away from it for a while. There's no sense in getting yourselves all worked up over this. Yes, it's NASA's future, and in a sense, our future. But it's not the end of the world if it flies or doesn't fly. It's certainly nothing to hurt other people's feelings over, or to take personal offense over. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[mlorrey]

Yeah. Tomnackid does have a good point. I for one value having existing databases of engineering and performance data to build on: if it ain't broke, don't fix it. It is data we all have already paid for, might as well make the most of it. That being said, if the CEV manufacturer were to offer it for sale to anyone, not just NASA, this could reduce the price, potentially. <br /><br />I'd look at the Apollo information as the Baby Boomers looked at, say, the VW Beetle: it was a design made by fascists and tyrants (Hitler), turned to benefit mankind in a phenomenal way. It wasn't the greatest concept, little payload capacity, but it was economical and gets people where the want to go affordably.<br /><br />If factories started pumping out Apollo knockoffs, with updated electronics and composite materials, we'd have a similar explosion in private space travel. It isn't the best design, but it is simple, stupid, and relatively easy compared to a lot of more modern vehicles (STS), which I think have proven to be failures.<br /><br />I'm not too worried about Project Constellation outcompeting private space travel. As usual, NASA is going to make everything too expensive for the proletariat, thus leaving the market wide open for those that can do the same for less. Now that control of space travel regulation is out of the hands of NASA, it is just a matter of time before we see a spacefaring version of UPS to drive the US Postal Service (NASA) to the edge of insolvency.

 

[rocketman5000]

I doubt that it would drive it to the edge of insolvency, but rather help it return to its roots, it could go back to only completing expirements in aeronautics and astronautics and allow crew delivery to NASA space stations to be either completed by private industry or to purchase commercial launch vehicles and operate them as they saw fit

 

[tomnackid]

<img src="/images/icons/frown.gif" /> Consider me properly chastised. After living through the post Skylab, pre Shuttle lull in American manned spaceflight I'm just so happy to have anything!

 

[tomnackid]

"Now that control of space travel regulation is out of the hands of NASA, it is just a matter of time before we see a spacefaring version of UPS to drive the US Postal Service (NASA) to the edge of insolvency. "<br />----------------------------------------------------------------------------------------<br />Actually the US Postal service is on the edge of insolvency because it is required by congress to deliver a first class letter to any address in the US for the same price. It is inherently inefficient because it has a job to do regardless of whether it makes a profit or not--like public schools and national defense. UPS can charge more for some areas than others or refuse to deliver to some addresses completely. This points out the fact that government is not like business. NASA is mandated by congress to explore and develop technologies (whether or not you think they accomplish that is another matter!). A private company has to luxury of only doing what is cost effective and profitable. <br /><br />PS: Thanks for saying I had a good point! Believe it or not I think you make some good points also.