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Cindy: Re. What would have happened after an abort? We wouldn't have reached Moon with Apollo-8, for sure. with all that would have had to be done over, not to mention the Congressional investigations. . . . If it hadn't been for the stirling performance by the (formerly despised) German Team and their Teutonic penchant for step-by-step engineering development emphasizing reliability above all, the old Soviets would have "won the race." The escape mechanisms, in my view, was just there to ease everyone's conscience for putting those brave guys in harm's way.
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Cindy: Re. What would have happened after an abort? We wouldn't have reached Moon with Apollo-8, for sure. with all that would have had to be done over, not to mention the Congressional investigations. . . . The escape mechanisms, in my view, was just there to ease everyone's conscience for putting those brave guys in harm's way.
*Hi dicktice. Yes, I see your point. Actually, I was wondering how the abort procedure worked -- what *actually* would have happened to the CM, etc. It would have involved splashdown or crashdown and those parachutes, I presume (!). And again, at what point was "abort" no longer an option? Ah well, maybe I've got too much curiosity for my own good. :-\
***
If anyone besides me is interested in purchasing the soon-to-be-released (this Spring, last I knew) DVD collection of the Saturn V, enter your e-mail address here and send a notification request:
[http://videoeta.com/reminder.html?id=63597]Notification of "The Mighty Saturns: Saturn V" DVD
I've mentioned this DVD collection (and its companion set, Saturn I and IB) in previous posts in this thread.
--Cindy
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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Cindy: Putting aside this unhealthy fixation with the now-defunct Saturn V for a moment: Doesn't the Soyuz's horizontal assembly and checkout, switchyard-type railcar ride out to the launch pad, just-in-time raising up of the entire rocket stack, followed by the almost always on-schedule launching with the dramatic retraction of the supporting props just before those volumptuous liquid fueled strap-on boosters pass by on the way up--up--up. . . . Doesn't all that live, everyday scene grip you, just a little?
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Personally, I wouldn't call an interest in a launch vehicle that had an spotless operational record, twice the cargo capacity of any existing booster and a lower cost per pound to orbit than any non-Russian booster (and that includes all the Proton and Soyuz hardware which are about twice the launch cost of the Saturn V) unhealthy.
As cool looking as the Soyuz lanches were, they are incapable of doing anything but having us muck around in LEO. The Saturn V had the capability to send us on sustained missions to Mars. Personally, if I want to watch pretty rockets, I'll watch those new Battlestar Galactica shows on the Sci Fi channel. I'm much more interested in the exploration of the solar system which the Saturn V would have given us.
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Cindy: Putting aside this unhealthy fixation with the now-defunct Saturn V for a moment: Doesn't the Soyuz's horizontal assembly and checkout, switchyard-type railcar ride out to the launch pad, just-in-time raising up of the entire rocket stack, followed by the almost always on-schedule launching with the dramatic retraction of the supporting props just before those volumptuous liquid fueled strap-on boosters pass by on the way up--up--up. . . . Doesn't all that live, everyday scene grip you, just a little?
*Hi dicktice. I've seen other rocket launches, including Soyuz, if I recall correctly. They are interesting to watch.
I'm not sure how many women are "into" rockets...generally, I am not. It's similar to trains; I enjoy watching them to a point and like the far-distant wail of them, particularly at night (soothing), but I'm not "into" trains (models, etc.). I should think you'd be more surprised I'm even interested in any rockets based on my gender (but of course I can't and don't speak for other women).
Besides the Apollo nostalgia associated with the Saturn V (as if that's not enough), it WAS a special rocket. Towering and majestic. It took us to the Moon. And as Shaun and SBird point out, basically flawless in its operations. How often in life do all those facets come together?
So many things in life seem to sucuumb to the "too good to be true" prediction, but the Saturn V didn't. It was good, it was true...and it was lovely.
The tremendous power unleashed in it, and on video it just keeps coming and coming -- filling frame after frame after frame of film. Incredible mechanical roaring behemoth.
All other rockets pale by comparison, in my opinion.
Besides the nostalgia and other sentiments expressed above, I am also interested in its construction, its fuel (as in the "Question about rockets & thrust thread"), I hope to see one being stacked on the DVD I intend to purchase, etc. I get "into" the Saturn V -- inside and out -- unlike any other rocket. Everything about the Saturn V intrigues me, from construction to blast-off. So it's not just sentiment.
--Cindy
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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Shame on me for stringing this out but, since I recollect the daily progress reports by NASA, during those wonderful open-skies days of full disclosure (spoiled by the ballistic missile threat of H-bomb anihilation, and the Vietnam obscenity), I can't resist commenting one more time regarding your sainted Saturn V:
SBird, you wrote in reply--to my wondering what things would be like today had we succeeded in carrying out an expedition to Mars, and discovered its sea-world geological history, not to mention possible life, back in the 1980d--that you weren't interested in the possible consequences of the Saturn V not being canceled. Now, it appears (to your credit I might add) that you are "much more interested in the exploration of the solar system which the Saturn V would have given us." [Ahem, welcome to the club.]
Cindy, I'm surprised at your playing the gender card! Besides, rockets and trains, you left out being "into" the new-generation airships. I remember that you were. How about a round-the world cruise circumnavigation of the Poles, touching down here and there, including on the seas and oceans . . . hmm.m?
Now Soyuz, with over a thousand "basically flawless" launches, is beautiful because it is routinely successful--like the Ford Model-T was (which I don't recollect!), perhaps a fair comparison relative to automotive progress, at least up to the 1980's, when development began to stagnate.
Apollo 8 was certainly "too good to be true." Except for the von Braun team, which fought NASA to have their say regarding the Saturn V design philosophy, it couldn't have happened as it did. But don't forget: von Braun was quite wrong regarding Apollo's original concept [no need to go into that] which wouldn't have "put a man on the Moon by the end of the decade" as promised. He, we now realize, had his sights set on Mars all along, and the final Apollo Solution didn't have the legs for that. His original proposal, which seemingly blinded him from the eventual LEM-based mission , did, however, have the legs for Mars in the Eighties. But that was before there were any orbiting space platforms. The Russians, too, had their sights on Mar, right from the beginning, and do so still.
A Saturn V is no longer needed, you must admit, since the long sought Mars Expedition can now be mounted from Low Earth Orbit. Why doesn't this seem to excite others besides (ahem) myself? Can it be that the Not Invented in the USA syndrome is rearing its ugly, shortsighted head?
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Dicktice: Cindy, I'm surprised at your playing the gender card! Besides, rockets and trains, you left out being "into" the new-generation airships.
*Well, I honestly don't see it as my playing the gender card (against my own gender!). How many women do you know who are interested in rockets? The articles, designs, posts (here), etc., related to it is nearly completely dominated by men. By the same token, I've never seen much evidence in my life of men being interested in crocheting and making afghans.
I did allow for the fact (deliberately so) that I certainly don't speak for other women; I just am commenting on what I've noticed.
--Cindy
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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dicktice - I don't mean to slight the impressive nature of the Soyuz program. Although it had a rough start, the operational performance of that program for the last 15 years is spotless. However, I think that it's a fallacy to think that medium lift boosters can get to Mars. I've already hashed this point over with GCNRevenger on the Interplanetary travel forum so I'm not going to eat up space here to repeat my arguments in full. Just suffice it to say, we are much better off using a heavy lift booster to get a spacecraft to Mars In orbit assembly, if the ISS has taught us anything, is a dodgy, slow and expensive process. The MArs mission will be more capable, cheaper and safer if it is assembled on the ground and lofted in one or two pieces. HLVs and cheap smaller launchers can still be used in concert. If we use a Saturn V clone to loft Mars Direct and a Soyuz equivalent to bring refuelling capability to gas it up in LEO, you can basically double the baseline masses Zubrin quotes in Case for Mars.
However, trying to do actual hard component assembly in space is a guarantee for cost overruns and disaster. It's hard enough to build spaceship on the ground - trying to do it in orbit is not a good idea until we have MUCH more experience in space.
For a practical Mars mission, we need a big, dumb launcher. The Saturn V worked, worked well and had the capacity to carry out what we want to do. Yes, it's outdated technology but it's outdated technology with a proven track record and a better cost ration than any of the stuff we've made since then. It's unlikely that we will resurrect the Saturn V. However, it's not a useless launch vehicle. If we still had the tooling to make it, we could be moiunting human missions to Mars right now. That's more than we can say for the Shuttle or any othe rlaunch technology we presently have.
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Looking at mass numbers and price per pound, Ares/Saturn V MarsDirect with an orbital rendevouz with a Zenit-2 lifted Mars insertion booster would seem an efficient way to go.
Anyway - since the shuttle derived fabrication infrastructure exists and Saturn V infrastructure does not - - even with plans there is no tooling, Ares is probably the biggest we can hope for in the near term.
Two shuttle B/C/Z might be another option.
= = =
As for Soyuz, NASA intends to pay $6 - 8 billion to design and deploy CEV. What if they just purchased 100 Soyuz flights off the shelf for say $3 billion ($30 million a pop, with a quantity discount) and spend the other $5 billion on a genuine deep space exploration vessel?
Two shuttle B/C lift a Mars craft into LEO for on-orbit assembly and 2 Soyuz delivers the crew and its off to Mars!
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SBird: It's because launches to LEO are essential NOW that I keep harping on current means, which leaves no alternative except Soyuz present, and follow-on versions said to be in the works. I never imagined the Mars ship to be a Soyuz, but an assembled in orbit conglomeration, rather than your "heavy lifter." Construction and checkout in the assembly building, then careful breakdown into bite-size components for multiple launches, and then "smart" reassembly in ISS vicinity with or without inflatable hangering in microgravity. Straightforward engineering, and capable of accumulating experience in space. How better to gain experience than by doing the Mars ship, I ask you? So what, if the work is done in Russia, since NASA won't be involved anyway?
Bill White: You're approach to the current, and urgent, need to access LEO on a routine basis fits my bill precisely. I hope SBird comes around, so the crew return-to-Earth phase can be taken up equally urgently. Then, private financing can begin with a minimum of new-concept hardware development (preferrably by retired space engineers on pensions, who want to see the thing accomplished in their lifetimes.
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Aw, gee, kids . . . it's just that it could have been so much more--same as the airships. Those old hulks (airships or rockets or Titanics) are so sad. .None of the Saturn V hardware is upgradeable, having been essential junked by Nixon & Company, way back when. Waste of time.
*Dicktice, I feel you are missing the point: The Saturn V was beautiful.
[http://astronautix.com/lvs/saturnv.htm]Saturn V- The Facts
Dicktice, I'm afraid you do seem to miss the point. To much lesser extent, you miss some of it too, Cindy. Yes, the Saturn V was a beautiful, awesome rocket in was that modern government-subsidized factory built rockets aren't, but that's only the begining of what makes it great. The Saturn produced 7.5 MILLION pounds of thrust on takeoff, and the end result was 118,000 pounds placed into low Earth orbit. That's simply unbeliveable! At least to my post-Apollo, raised on the Space Shuttle eye.
I'll admit that at first I was skeptical about raising the Saturn V on such a high pedistal. My initial reaction was "Don't we have something better now?" The unfortunate fact is no, the most powerful rocket engines ever developed were designed in 1959. If we put our minds to it, we certainly could come up with something better than this, but for now it's completely unrivaled as far as brute force goes. After reading the above article, I gained new repect for this monster.
What I would give to have been around back when people cared. The idea that you could fill a DVD full of broadcasts from a single mission sounds utterly amazing to me. Earlier some of you were discussing weither you were old enough to remember any of the Saturn launches, I'm not even old enough to remember the Soviet Union being mentioned (Except with the prefix "former-")! If I try to figure out what's going on with a certain mission, it usually involves keeping an eye on CNN for up to an hour just to see ten words about it appear on the ticker. Understandibly (Perhaps?), I really wasn't too interested in space before the age of ten, simply because it was so hard to even find one live broadcast from a single mission. Nobody cared.
Had it not been for IMAX films like Mir and Space Station 3-D I probably still wouldn't care to much about the subject. I suppose the event that really turned my view around was seeing a space shuttle undock from Mir once while watching from my backyard. Just after sunset a bright white dot, obviously not an airplane, zoomed overhead and was gone on the opposite horizon in two minutes. 90 minutes later it came over again, but with a second dot moving subtlly away from it! That was what finally got me hooked. Naturally, I take a lttle offense every time someone lobbies to get rid of the ISS, just a personal thing I guess.
Just one final thing, why did you bring up the subject of women and rockets, Cindy? I don't think it was really necessary. Obviously, you love the Saturn V regardless of your gender, so it's a non-issue. Come to think of it I'd rather talk about the Saturn V, so I'll just leave that there.
A mind is like a parachute- it works best when open.
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But launches into LEO are not essential now... when ISS is done using Shuttle, then PlanBush will pull the plug, beyond possible light cargo rockets, and then its off to the Moon.
Using present-day EELV technology it is possible to mount a small (no Lunar construction) to medium (minimal construction) Lunar expedition by cutting the whole thing down into small chunks and sending them over with Solar/Ion tugs, but Mars is a whole different ballgame.
The size of the ship needed, the much larger requirements for surface payload mass for a minimal mission, the distances and reliability involved are simply much greater then cis-Lunar travel. The efficency hit of making a small ship from medium launchers isn't that bad, but making a very large vehicle out of space-legos gets unacceptable fast. The extra weight of smaller tanks, the extra bulkheads, the attach point hardware, the docking clamp sensors, the lack of a space tug, etc etc... The excess time and complexity of making a large (and reliable) craft from small pieces makes an EELV Mars ship an extremely expensive and terribly difficult proposition; and would almost certainly make HLLV launch cheaper, faster, and safer.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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To much lesser extent, you miss some of it too, Cindy. Yes, the Saturn V was a beautiful, awesome rocket in was that modern government-subsidized factory built rockets aren't, but that's only the begining of what makes it great. The Saturn produced 7.5 MILLION pounds of thrust on takeoff, and the end result was 118,000 pounds placed into low Earth orbit. That's simply unbeliveable!
*Hi, Mad Grad Student. Perhaps you missed a post or two of mine (?). I've -not- simply been referring to the Saturn V's physical appearance (as referenced in yesterday's two posts by me, I'm interested as well in its construction, its design, how it was fueled, etc., etc.).
I wrote yesterday -
"The tremendous power unleashed in it, and on video it just keeps coming and coming -- filling frame after frame after frame of film. Incredible mechanical roaring behemoth...
Besides the nostalgia and other sentiments expressed above, I am also interested in its construction, its fuel (as in my "Question about rockets & thrust" thread, also in the Science & Technology folder), I hope to see one being stacked on the DVD I intend to purchase, etc. I get "into" the Saturn V -- inside and out -- unlike any other rocket. Everything about the Saturn V intrigues me, from construction to blast-off. So it's not just sentiment. "
More than "just aesthetics."
--Cindy
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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Hey...I just found this link...it's the orginal press kit for the Saturn V, with all kinds of facts and figures, with illustrations, etc.
[http://history.msfc.nasa.gov/saturnV/]Original Saturn V press kit from the '60's
There's no denying the fact that the Saturn V was one awesome rocket...I think NASA should build a Saturn VI to take us to Mars....it'd certainly solve a lot of problems in regards to lift capacity...lol
B
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I'll agree with GCNRevenger - going to the moon with your approach is feasible. Getting to Mars is just too chancy. Another important point is that Mars requires an atmospheric reentry which the space-lego ™ approach is rather poorly suited to. The moon is just a retro rocket approach which doesn't mind big, lumpy structurues.
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Looks like those British folks failed in saving the old launch towers for the Saturn.
From NYTimes, reg required:
[http://www.nytimes.com/2004/03/30/scien … 0TOWE.html]http://www.nytimes.com/2004/03/30/scien … 0TOWE.html
But just in case:
APE CANAVERAL, Fla., March 29 — Destruction of the tower used to launch the two most important Apollo missions to the Moon has begun after a British organization failed to gain enough support to save it.
"They've started cutting, and we haven't got the $40 million that we need, or even a commitment toward that," said Ross B. Tierney, a wealthy space buff who founded the Space Restoration Society to save the tower from the blowtorches.
Mr. Tierney said he had hoped to find enough investors and money to return the red 440-foot-tall gantry to its original might as a "monument to the achievements of Apollo."
Called the launch umbilical tower, the structure was used to keep electrical, data and fuel lines connected to Saturn rockets right up to liftoff.
Demolition began last week. On Monday, steel beams and other dismantled parts of the tower were piling up at the demolition site at the Kennedy Space Center here.
The National Aeronautics and Space Administration used the tower to launch Apollo 8, which first sent astronauts around the Moon in December 1968, and Apollo 11, which took Neil A. Armstrong and Col. Edwin E. Aldrin Jr. to its surface in July 1969.
The Environmental Protection Agency had ordered NASA to get rid of the tower segments and decontaminate the soil, if necessary. The major concern was that the original lead-based antirust coating and other toxic substances might seep into the soil and reach the water table.
After the tower was dismantled in 1984, the pieces were stored in a grassy, fenced area of the space center, where they have been rusting. In its proposal, Mr. Tierney's organization failed to address a major E.P.A. requirement, said Burton R. Summerfield, chief of the environmental division at the center.
Since the tower's segments are considered toxic waste, federal regulations prohibit their sale, Mr. Summerfield said.
Mr. Tierney says he is still determined to obtain some of the parts.
"Perhaps one of the service arms, or maybe two, if they can give them to me at a reasonable price," he said.
Short of that, the tower, which survived the red glare of the rockets, will melt in a white-hot blast furnace.
I suppose a return to Saturn is now completely out of the question.
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Hmmm, that's a shame. However, I think that the biggest barrier to rebuilding the Satrun V is rebuilding the Saturn V. Most of the original contractors don't exist anymore and the toolings are gone. It would take billions to redevelop it at this point. At that rate, we're better off just redesigning it from scratch for higher performance. Building a new launch gantry is annoying but probably not a large cost by comparison.
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Take a few minutes to browse the collection of late-term Saturn or medium-term Nova rockets as Astronautix.com... And say we did want to build a new HLLV in the Saturn-V class region for as little headache as possible.
One of the schemes used to cheapen or augment Saturn's capacity was the use of large solid rocket engines. We already have some, the 5-segment Shuttle SRB engines.
Next on the list is first stage liquid propellant. Since we have the SRBs already, and mass target is not that high, LH2/LOX engines hold the edge over the old LOX/RP1 engines like F-1 & F-1A. Hey, we've got those already too, Boeing's RS-68 cryogenic first stage engine.
We'll need a big fuel tank to feed the 68's and to put the next stage on that can handle the stress from the giant SRBs... say we've got that too even, the Shuttle main tank, in production this very day by Lockheed.
Upper stage engines, also cryogenic, dig up the old J-2? Nope, got the RL-10 and soon to have the RL-60, off the shelf and available when construction time comes around.
...Shuttle, and even moreso SDV, is not so far removed from Saturn's decendants as you might think.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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Take a few minutes to browse the collection of late-term Saturn or medium-term Nova rockets as Astronautix.com... And say we did want to build a new HLLV in the Saturn-V class region for as little headache as possible.
One of the schemes used to cheapen or augment Saturn's capacity was the use of large solid rocket engines. We already have some, the 5-segment Shuttle SRB engines.
Next on the list is first stage liquid propellant. Since we have the SRBs already, and mass target is not that high, LH2/LOX engines hold the edge over the old LOX/RP1 engines like F-1 & F-1A. Hey, we've got those already too, Boeing's RS-68 cryogenic first stage engine.
We'll need a big fuel tank to feed the 68's and to put the next stage on that can handle the stress from the giant SRBs... say we've got that too even, the Shuttle main tank, in production this very day by Lockheed.
Upper stage engines, also cryogenic, dig up the old J-2? Nope, got the RL-10 and soon to have the RL-60, off the shelf and available when construction time comes around.
...Shuttle, and even moreso SDV, is not so far removed from Saturn's decendants as you might think.
As a friggin history major, it is posts like this that cause me to believe that the technicalities of how to get to Mars are relatively easily solved compared with the politics and finding a WHY that will persuade those who control the funding.
Lets just say Zubrin has me hyp-no-tized.
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Okay, sorry I accused you of not seeing the Saturn's true beauty, Cindy, there were so many comments made since the start I probably skipped over a few. That's a real shame that they're tearing down that tower, we're losing a piece of actual space history here. It makes you wonder why more people didn't lobby for it's protection.
Unfortunately, my admiration for the Satrun V was significantly diminished when I found out that the shuttle stack actually can put about 70% of the payload into orbit. Why doesn't the new Bush plan just use that? Doesn't seem like such a bad idea to me.
I didn't mean to diminsh the Saturn's raw mystique, I just wanted to look at the numbers. They're both pretty nice rockets.
A mind is like a parachute- it works best when open.
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Have you noticed that "mystique" rhymes with "antique"? I know, I'm bad . . . but what is it (aside from nostalgia perhaps) that drives you to insist on going the Saturn V way, which inherently requires capsule re-entry? (Been there/done that!)
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You mean besides the fact that capsule reentry is cheap and reliable? Winged vehicles, while having an advantage of eing able to control reentry landings sites, present far more significant engineering challenges. There's a reason for why NASA has all but abandoned winged reentry.
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YIPPEE!!!!!! "Mighty Saturns: Saturn V" on DVD is NOW AVAILABLE!!!!
I didn't get e-mail notification from that one web site which offered it. I've been on the look-out for its availability, and saw it in a link to Rik's post about the Mars "sample return mission" in Unmanned Probes.
Rik, you made my day without even intending to! ::hug::
[http://www.spaceflightnow.com/store/vid … urnsv.html]Click!
--Cindy
::EDIT:: A slight "snag" -- the link above will allow you to "PRE-order." I checked amazon.com; DVD is officially released on the 13th and can pre-order with them too. Well...what's another week?
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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"Above the CM was the emergency escape system..."
[http://www.nasm.si.edu/collections/imag … aturnV.htm]Click
A really good resource for each stage, how long it burned, altitude, speed, etc.
What I want to know about is that "emergency escape system." How did it work? If one of the Apollo missions had had to abort the mission, at what point did they no longer have that option (I presume before Stage 3)? And what exactly would have happened after an abort? What was the emergency escape system plan?
--Cindy
::EDIT:: I Googled for answers to my questions, but all the hits I get only refer back to the emergency escape system by name (no explanations).
*Awright...I'm not sure -this- really answers the "emergency escape system" question I had, but I found the following in _Lost Moon_ (Apollo 13) -- I'll summarize the paragraph (because of copyright issues).
Okay, the authors (Lovell and Kluger) say that there were a few ways to bring home a ship in distress during an aborted lunar mission. The direct abort was the most straightforward. The crew could turn the command-service module around in order to fly tail-forward. Then they'd fire the 22,500 pound hypergolic engine (oooooo...never heard of "hypergolic" before) at full throttle for more than five minutes (exact duration not mentioned). This manuever was designed to bring the craft (which might be traveling along at 25,000 mph) to a complete standstill, then get it moving just as fast in the opposite direction.
Hmmmmm. Sounds like a deep-space "bootlegger's turn."
I really am in awe of the minds which can devise such things. ::sigh::
--Cindy
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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Hi Cindy!
From memory, I believe hypergolic means that no ignition system is required for the fuel and oxidant. When you pump them simultaneously into the combustion chamber, they spontaneously react. This not only simplifies things, it makes things safer too because ignition is guaranteed - a very handy thing when your life depends on it!
There would have been a certain 'window' of opportunity on the 3-day coast to the Moon when a direct abort was possible. The combined Command/Service/Lunar Module (CSLM) left Low Earth Orbit (LEO) with a velocity of some 24,000 mph, too fast for the Service Module engine to be able to reverse the CSLM's trajectory. But Earth's gravity gradually slowed the craft until, at the point where the Moon's gravity balanced that of Earth, the velocity began to increase again. At its slowest, the CSLM was moving at just a few thousand miles per hour and, either side of that point, was the 'window' during which the Service Module engine had enough Delta-V (Oomph, that is!) to bring about the reversal of course needed to abort the mission.
Otherwise, they could loop around the Moon as part of the abort, which had the disadvantage of taking longer. And I guess, when things have gone badly wrong, the sooner you can get home the better.
Sorry I don't remember details of the escape tower which sat atop the Command Module. I do remember it was supposed to accelerate the astronauts away from the launch site in the event that the Saturn V decided to expend all its energy at once ... KABOOM!
I don't recall how far into the launch sequence that tower would still be safe or effective to use. I imagine it would depend on the speed through the atmosphere; there being some point beyond which shock wave ahead of the capsule would make an abort impracticable(?)
The word 'aerobics' came about when the gym instructors got together and said: If we're going to charge $10 an hour, we can't call it Jumping Up and Down. - Rita Rudner
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