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Old August 29th, 2011, 01:27 AM
e of pi e of pi is offline
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Eyes Turned Skywards

"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."

--Commonly attributed to Leonardo da Vinci

Truth is Life and I have been working on this for a while, and we're finally ready to begin posting this. The below is a teaser for our new project, Eyes Turned Skywards. The first real post will follow in the next few days, and after that we're planning on a weekly posting schedule. Hope everyone enjoys this as much as Truth and I have enjoyed making it.
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Last edited by e of pi; August 29th, 2011 at 06:54 AM..
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Old August 29th, 2011, 04:47 AM
Shevek23 Shevek23 is offline
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The teaser is hilarious, considering the conventional wisdom of our OTL space-fans who post here that the Shuttle was in retrospect, evil and dumb and everything would be so much better if we only didn't get caught by that tar-baby!

It's amazing how much greener the grass is in some other timeline!
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Old August 29th, 2011, 04:51 AM
Redem Redem is offline
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That was a nice teaser, hope to see other presensation of that format or any variation of it
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Old August 29th, 2011, 04:53 AM
Ariosto Ariosto is offline
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Don't see enough TL's of this nature, so it is a nice change. Looking forward to what you and Truth put together.
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Old August 29th, 2011, 04:58 AM
Workable Goblin Workable Goblin is offline
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Originally Posted by Shevek23 View Post
The teaser is hilarious, considering the conventional wisdom of our OTL space-fans who post here that the Shuttle was in retrospect, evil and dumb and everything would be so much better if we only didn't get caught by that tar-baby!

It's amazing how much greener the grass is in some other timeline!
Well, think of the '70s attitude towards the thing without ever being dosed by the cold shower of reality to wake up. It's not quite the same, but still fairly close.

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That was a nice teaser, hope to see other presensation of that format or any variation of it
We're planning on doing a couple of posts in this format later on, last time I checked at least. You can thank Jared for the idea--I got it from LORAG, ran it by e of pi, and we both thought it was a great way to introduce the TL.
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Old August 29th, 2011, 06:17 AM
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We're planning on doing a couple of posts in this format later on, last time I checked at least. You can thank Jared for the idea--I got it from LORAG, ran it by e of pi, and we both thought it was a great way to introduce the TL.
Yeah, it was fun to write, and hacking up screenshots to make it was pretty easy once I figured out what I needed. We do have a few more planned, but there aren't any others in the buffer, so it might be a few months before we get to another one. They have some of the same issue as a normal DBWI, in that it sounds forced if you cram too much exposition in, so they're really best as teasers like this, or to give insight into the feelings of those people inside the TL world.
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Old August 31st, 2011, 04:07 PM
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As promised, here's the next installment in Eyes Turned Skyward.



Eyes Turned Skyward, Post #2:

When Nixon won the 1968 Presidential election, the future of the US space program looked grim. Strongly identified with his hated rivals, Kennedy and Johnson, it was practically a symbol of his near-decade in the political wilderness. And yet...and yet...some element of the American psyche has made every president, from Eisenhower down to Clinton, seek not to destroy the program, but put their own stamp on it. Nixon was no different, and after briefly considering the interim Administrator Thomas Paine as the man to lead Nixon's transformation of the program, decided that the manager of the Apollo Spacecraft Program Office, George M. Low--the man, in short, responsible for making sure that the Apollo spacecraft would be a safe and reliable method of transporting men from Earth to the Moon--would be an ideal pick as only the third Administrator of the National Aeronautics and Space Administration. Low would serve into Carter's term, having a large impact impact on NASA, perhaps larger than the legendary James Webb.

Once confirmed as Administrator in mid-1969--just in time to see the fruition of his work at the ASPO in the triumph of Apollo 11--Low quickly proved a perceptive and far-seeing leader. Low realized that the techno-optimism that had driven the '50s and '60s was coming to a close, and the coming decade would be an era not of unbounded growth for the space program, as some at NASA hoped, but instead, as Jerry Brown would later put it, an era of limits. It was not just the war in Vietnam, nor the war on poverty, nor the war in the cities. Indeed, there was a growing opinion that technology was a war against the planet itself, that the high technology symbolized by a man walking on the Moon was fundamentally destructive and immoral, that it should be abandoned. To the extent possible, the mission of the Administrator at the start of the decade would be to convince Congress and the public that spaceflight could play an important role in all these problems, a role symbolized by the partnership with the National Oceanic and Atmospheric Administration that was beginning the public weather satellite system. At the same time, with the success of the civil rights movement, the burgeoning women's rights movement, and the nascent gay rights movement, the all white male (and mostly test pilot) astronaut corps was increasingly out of step with the country. This, too, was damaging the space program, as the image of astronauts as elite heroes exploring a new frontier was slowly changing into a view of them as elitist jocks having fun at public expense. It was clear that the astronaut needed to be remade as a dedicated public servant, and a vital part of that would be including minorities and women in future astronaut groups. All this, too, would have to be done on a far smaller budget than had achieved lunar landings in less than a decade from the beginning of the program.

Post-Apollo planning had of course been in progress for some time, both within NASA itself and amongst all those outside of the Administration who favored spaceflight. Most, naturally enough, concentrated on the reuse of the capabilities developed during the Apollo program, such as the heavy-lift capacity of the Saturn V or the ability to land on the Moon demonstrated by the LM in July 1969. The efforts doing so were gathered under the heading of the Apollo Applications Program, which would see a series of increasingly advanced and long-term lunar missions and the launch of basic orbital stations during the early part of the decade, just following the basic Apollo flights. In the middle of the decade, a reusable logistics "space shuttle" and a corresponding deep-space "nuclear shuttle" would be developed, and then used to establish major stations on and around the Moon and in Earth orbit. This would be followed up in the 1980s by a mission to Mars utilizing the technology developed earlier. Such a project would require billions of dollars but would fully leverage the capabilities developed by Apollo. Many of the ideas were very clever in their reuse of existing technology, such as the "wet workshop" idea for basic space stations. A wet workshop was a Saturn IB upper stage launched into Earth orbit, emptied of its fuel, then pressurized and filled with equipment for a short-term mission by an astronaut crew, an audacious but brilliant plan to get a space station on the cheap. Nevertheless, despite such economies, AAP would be very expensive, and Nixon and Congress were sending out clear indications that such expense could not be sustained. Shortly after Low's appointment, Nixon had asked the National Aeronautics and Space Council, chaired by his Vice-President Spiro Agnew, to develop and present a plan for NASA's future. At first, this seemed like a golden opportunity to produce a plan that would continue America's advance in space indefinitely, especially considering Agnew's dedication to the prospect. However, shortly reality set it. With the Vietnam War still raging in Indochina and Johnson's massive and costly domestic agenda not on the cutting block, neither Nixon nor Congress showed any enthusiasm for an expensive space exploration program, with the latter continuing to cut back on investment in the nuclear rockets assumed at that time to be needed for trans-Mars voyaging even after Armstrong's triumphant first step. The message was clear to Low, and despite Agnew's energy he began to turn towards the plans proposed by the Administration and OMB.
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Old August 31st, 2011, 07:55 PM
RazeByFire RazeByFire is offline
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Could Apollo do a polar orbit? Just thinking that, if NASA needed something spectacular, maybe finding ice on the Moon would be enough to get people thinking that it needed to be given a bit better budget.

Just enough of a jolt in the mind of the public to push Nixon into approving extended Apollo hardware.
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Old August 31st, 2011, 08:31 PM
Workable Goblin Workable Goblin is offline
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Could Apollo do a polar orbit? Just thinking that, if NASA needed something spectacular, maybe finding ice on the Moon would be enough to get people thinking that it needed to be given a bit better budget.

Just enough of a jolt in the mind of the public to push Nixon into approving extended Apollo hardware.
I don't know that finding ice would be possible with '70s era technology, particularly computers, radar, and remote spectrometers. In any case, such a discovery might actually be detrimental to NASA, particularly in Congress, since it would significantly support further exploration and colonization (which would be significant ongoing expenses--something very much opposed by a large part of the "political class" at that time. It's part of the reason we signed the Outer Space Treaty and worked on the Moon Treaty). Also, we're planning on taking this TL in a somewhat different direction--you will see!

EDIT: Also, I do not believe the CSM had the necessary delta-V to capture into and escape from a lunar polar orbit. Maybe if you had a throwaway LM to soak up part of the delta-V, but that would be getting ridiculously jury-rigged for something that there isn't any great historically plausible reason to undertake.
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Old August 31st, 2011, 10:20 PM
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Yeah, I don't believe the CSM had the delta-V with the LM attached to perform that kind of plane change. However, without the LM, there's a lot more delta-v available (same fuel mass, smaller payload), but now you're talking about sacrificing a landing (and a Saturn V) for a stunt they can't be sure at the time will generate results. Like Truth already said, it's a nifty thought, but there's insufficient reasons to make that decision at that time.
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Old September 1st, 2011, 10:23 AM
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Old September 1st, 2011, 02:47 PM
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Old September 5th, 2011, 01:34 AM
Shevek23 Shevek23 is offline
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And a technical question--sorry if I work out the answer before I finish writing this sentence, that's the way my mind works, have to engage the mouth before the brain operates...

Anyway, why is a Lunar polar orbit significantly more costly of delta-V than an Lunar equatorial one? From the Moon's point of view, Earth is sending projectiles on a path that, by the time it's close to Luna, is almost coming straight in to the Lunar center of mass, right? It's actually off to the side a bit, so if there were no braking impulses fired, it comes in on a nearly parabolic path, skewed a bit by Coriolis force (from the point of view of a frame rotating with the Moon's rotation). That is, a minimum energy trajectory from Earth would have coasted nearly to a stop somewhere near the vague "border" between space dominated by Earth's influence and that where the Moon's dominates. I suspect the energy is such that actually if the Moon didn't exist it would be a very eccentric ellipse with the apogee a bit closer in than Luna's center of mass; the name of the game is to just barely coast past the "ridge" beyond which we have a gravitational dimple formed by the Moon's mass. Actually in a rotating frame we have to throw in the centrifugal force component too, centered on whatever mass we choose as the center and of magnitude based on whichever angular speed we arbitrarily deem is inherent in the frame--if for a Luna-centered system we choose some speed other than Luna's actual rotation then there is a left-over positive or negative rotation of the Moon itself in that frame. So the "natural" choice is to match Luna's rotational speed and it holds still in that frame, but the math works out the same no matter which speed (including zero, for a proper inertial frame) we choose. But the description of the static potential field, and hence the location of the "ridge," depends on that arbitrary choice. The potential field only matches the actual gravitational field if we choose zero and an inertial frame.

Ok, anyway it's lobbed from Earth to just barely skate past that, and then from a slow crawl start infalling, with a slight skew of residual velocity to send it into some parabola or hyperbola--correct me if I'm wrong but without some course changing impulse at some point there is no way it can be a near-ellipse relative to the Moon, in any frame it must work out that without a braking impulse it must escape Luna again (unless it hits!) and then it's back in orbit around Earth until its orbit and Luna's potential well happen to match up again for another go-around.

Now I understand that if initial injection from Earth works with its initial parking orbit, there is some savings of delta-V to reach that minimal "pass" region into Lunar space. Giving it a bit of push north or south requires extra thrust, without which it crosses the "pass" in the plane of Luna's orbit--for a polar orbit we want it to arrive there a bit north or south of that plane and for that we need to spend some extra thrust in initial injection.

But I don't imagine we need anything like the sort of change of momentum we'd need to shift from a Terran equatorial orbit to a Terran polar orbit! Just a bit of a nudge, and the ship's path is taking it "up" or "down" above the plane, at a rate that is getting braked by both Earth's pull--but only a slight fraction of it, and that declining both as the ship gets distant from Earth and as the angle between the path and the direct line from Earth to Moon (where the Moon will be when the ship gets close, that is) declines. And by the Moon, which is also pulling back to the plane, and that gets stronger with both influences, but the Moon is small and it's not a major factor until you get close.

So, I don't think it has to be very high above or below the plane when it gets to the edge of Lunar space, and once it gets past the transition region it just needs to be sidestepped a bit for its path to pass over the Lunar pole rather than the equator. (It will pass over the equator at perilune no matter what of course, you know what I mean--when it's passing the plane at right angles to the Earth-Moon radius line, that's what I'm talking about, not 90 degrees later at perilune).

In short, what I'm thinking is that to orbit over the Moon's pole, all that is required is a somewhat longer, or higher-acceleration (hence lower payload-mass for a given injection stage) injection boost from Earth parking orbit. To make it pass exactly over the pole we'd also have to kill the angular momentum that's gifted to the ship because it starts from Earth parking orbit, or for a direct launch from the rotation of the launch point, as well as supply the whole polar drift. That's why it's more costly.

But it seems to me the cost is all in the initial launch from Earth or Earth parking orbit, not at all a matter of the capabilities of the CSM's braking engine to achieve lunar orbit. It would be insanely costly to approach on a standard orbital-plane orbit and then do an orbit change to put it into Lunar polar orbit, obviously. But would it really cost a lot compared to that standard orbit, to aim for a polar instead of equatorial approach from injection? It all depends on how crucial that momentum from the initial orbit is. And even then, if that makes a huge difference, I'd think going for Lunar polar would be a matter of launching into a high-latitude Earth parking orbit instead of an ecliptical one. (Not an Earth polar orbit; our planet's axis is tilted relative to the ecliptic while the Moon orbits close to it, so actually the parking orbit would be inclined to 67 degrees relative to our equator.)

I know high-latitude orbits are more costly than equatorial ones, but not dramatically so; an Apollo mission to a Lunar polar orbit would require a lesser payload mass (or more powerful rocket stages) but I'm guessing just by 10-20 percent, not a mission-killing order of magnitude!

Sorry I'm rambling but the mechanics are still not clear to me--am I not right that it all stems from the initial path from Earth and the braking job the Service Module has to do is essentially the same? And if that initial lobbing into a polar path does significantly restrict the payload, so the modules sent moonward are significantly lighter, doesn't that mean that with the same engine the SM just has a shorter burn to manage to put the craft into orbit? Hence less fuel for it and we can make up some of the shortfall for the payload that way?

The cost is all in the lower stages, I'm thinking. True or false?
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Old September 5th, 2011, 08:40 PM
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Thank you as well!

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And a technical question--sorry if I work out the answer before I finish writing this sentence, that's the way my mind works, have to engage the mouth before the brain operates...
No problem. Sorry for the delay in my response, but I've been away from solid wifi, and while my phone is suitable for browsing, it's not suitable for doing the kind of research I wanted to before answering this question.

Quote:
Anyway, why is a Lunar polar orbit significantly more costly of delta-V than an Lunar equatorial one?

*middle snipped*

And even then, if that makes a huge difference, I'd think going for Lunar polar would be a matter of launching into a high-latitude Earth parking orbit instead of an ecliptical one. (Not an Earth polar orbit; our planet's axis is tilted relative to the ecliptic while the Moon orbits close to it, so actually the parking orbit would be inclined to 67 degrees relative to our equator.)

I know high-latitude orbits are more costly than equatorial ones, but not dramatically so; an Apollo mission to a Lunar polar orbit would require a lesser payload mass (or more powerful rocket stages) but I'm guessing just by 10-20 percent, not a mission-killing order of magnitude!

Sorry I'm rambling but the mechanics are still not clear to me--am I not right that it all stems from the initial path from Earth and the braking job the Service Module has to do is essentially the same? And if that initial lobbing into a polar path does significantly restrict the payload, so the modules sent moonward are significantly lighter, doesn't that mean that with the same engine the SM just has a shorter burn to manage to put the craft into orbit? Hence less fuel for it and we can make up some of the shortfall for the payload that way?

The cost is all in the lower stages, I'm thinking. True or false?
Unfortunately, I've yet to take any orbital mechanics classes (those aren't available for me for another few semsters), so I don't have the knowledge to answer your question directly based on my own analysis. I can only fall back on published data and historical plans. No plan such as yours has been considered to my knowledge, so I can't say if you'd actually save anything in TLI or LOI if you tried to go into a lunar polar from a 67 degree inclined Earth parking orbit. What I can say, however, is that you couldn't get an Apollo lunar mission to that parking orbit with a Saturn V launched from the Cape.

The Saturn V could inject about 127 metric tons to a 170x170 km orbit at 30 degrees according to published figures, which I checked by entering data on each individual stage of the vehicle into this launch vehicle performance calculator. Changing the orbit to a 63 degree inclination results in an estimated payload of a whopping 449 kg, a performance drop of not 10-20%, but rather 99.6%. Inclination changes on that order are indeed "mission-killing" due to the need to fly a so-called "dogleg" trajectory to achieve them.

Thus, while I can't say whether or not launching to polar orbit from a highly inclined Earth parking orbit would be advantageous if you could get there, the point is academic because the Apollo hardware could not reach that parking orbit to begin with. Perhaps if you could launch from Vandenberg, which at 51 degrees is far better suited to such high-inclination orbits, but not from the Cape, and that's simply not on the table for our TL, not during the Apollo years. (As for the future...I plead innocent on the grounds that I don't want to comment on portions of the TL that have yet to be written.)
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Old September 5th, 2011, 09:27 PM
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In addition to what e of pi said, returning from the Moon to Earth using a high-inclination low lunar orbit for parking imposes a significant delta-V penalty if you want to be able to get back to Earth at any time (I haven't done celestial mechanics either, so this is what I understand from my reading). It's not insurmountable--IOTL, the Orion was supposed to both support missions to the poles (for obvious reasons!) and was supposed to use LLO for its staging ground, something which meant that it had to fly into high-inclination LLOs--but it is certainly problematic. Again, IOTL, the need to supply enough delta-V was a major driver of Orion requirements, despite the Orion SM actually having fewer burns than the Apollo SM (due to use of the new lunar module). The Apollo/Saturn combo just wasn't designed to do those sorts of things, and while it could probably be modified with enough work, that wouldn't really be on the cards for maybe one mission as the program is winding down. If there was an expanding program--but I think the last post has made it clear that the next period for NASA is going to be one of shrinking budgets and more limited goals, much like IOTL, and there won't be the money or will for an indefinite commitment to Moon landings.
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Old September 7th, 2011, 06:44 PM
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Well, folks, it's Wednesday, and you know what that means: New Eyes Turned Skyward! When we last left off, the new NASA Administrator George Low was facing a future of shrinking budgets, and having to make hard choices on what to cut and what to save.

Eyes Turned Skyward, Post #3:

The plans Low was considering envisioned a space-station centered strategy for NASA, where logistics and crew would be dealt with not by an advanced (and expensive) shuttle craft but rather modified variants of existing spacecraft, particularly the Apollo CSM and Saturn IB (though the Gemini and Titan III were advanced as options by their respective manufacturers). As NASA thought prior to Kennedy's famous speech generally held that the main goal of the space agency should be to construct a permanent space station, vaguely followed by a flight or two around the Moon (but no landings, at least until later), this was in many ways a return to form. As eventually adopted in the FY 1971 budget, the Skylab program would consist of two main parts. After the launch of Apollo 18, a "dry workshop"--essentially the wet workshop constructed on the ground and therefore much more capable--named "Skylab" would be launched into LEO. This would carry as its main piece of scientific equipment a solar telescope, the Apollo Telescope Mount, originally intended for AAP projects. In addition, it would carry a wide variety of remote sensing equipment, intended for tests of both the equipment for future remote sensing missions and of the ability of astronauts to contribute to or detract from Earth observation, a number of biological experiments probing the effects of space on living organisms for the benefit of future astronauts, and a number of materials experiments investigating whether the unique environments of space could be used in manufacturing processes impossible on Earth. In all this it was quite similar to the contemporaneous Soviet Salyut program, right down to the provision of several non-Skylab "free-flyer" missions to test experiments and capabilities before using them on the station itself. Once this preliminary program was wrapped up, the second part would begin. A heavily modified variant of the backup built for the first Skylab--Skylab B--would be launched by the last Saturn V into a similar orbit. This advanced Skylab would delete the solar telescope, but otherwise be far more capable, designed for continuous resupply, on-orbit repair, and even perhaps a degree of expandability. This would be occupied by a series of crews operating many different experiments, including (perhaps) some Japanese or European ones, for 5-6 years after launch. After Nixon and Brezhnev agreed to start the Apollo-Soyuz Test Project, that too was included in the plan. After the initial test flight, Skylab B would play host to several Soyuz and Apollo crews at the same time, for stays of up to as much as 90 days together, becoming the "International Skylab". Afterwards, additional modules (suitably equipped for automatic or semi-automatic rendezvous and dock operations) might be launched, further extending the station's capabilities, or a whole new station, designed from the ground up using "lessons learned" by the Skylab missions, might be developed. While this promised a new era of international cooperation, at NASA the technical challenges of the plan were wearing, for NASA's equipment (designed to achieve the Moon landing ASAP) was ill-suited for the missions at hand, in particular the Block II CSM and the Saturn IB rocket.

The Block II was, especially after the modifications following the Apollo 13 accident, a reliable and capable spacecraft. Still, it had its shortcomings for the new type of space station missions planned for the 1970s and beyond. In particular, at its full wet mass--the mass of the entire spacecraft while fully fueled and carrying its maximum payload--it weighed over 65,000 lbs (30,000 kg), far more than the comparable Soviet spacecraft, the Soyuz, which had a mass of just 14,500 lbs (6,500 kg) while providing only 50% more habitable volume for the crew. While it was far more capable than its Soviet equivalent--the Soyuz itself was not capable of being used on circumlunar flights, and the two variants that were were far less commodious than either Soyuz or Apollo--those capabilities were entirely superfluous, and prevented it from being launched by either the Saturn IB or the planned Saturn IC without carrying a smaller-than-capacity fuel load. As such, it was of no surprise to anyone that in FY 71 NASA requested funding for the development of the "Block III" variant, which was immediately contracted out to North American Rockwell. It would feature enhanced on-orbit life while in 'sleep' mode, reduced fuel space, a combination of parachutes and airbags that would allow NASA to dispense with the expensive naval recovery fleet, and many other improvements that would make it lighter but more capable of achieving the missions placed upon it.

Due to the need for continuous resupply and crew cycling, low cost reliable launch vehicles were a must for NASA's forthcoming projects. However, though the Saturn IB was reliable, it was certainly not low cost in comparison to the other launchers available at the time. While it cost five times more to launch than the Titan IIIC, it was only capable of lofting two-fifths again as much payload, a poor bargain in anyone's book. Various proposals to replace or improve it had been floated for some time, ranging from simply upgrading its engines and decreasing its structural mass to outright disposing of it for a new rocket, perhaps one based on a huge solid first stage or the S-II stage from the Saturn V. Under the circumstances the agency found itself in in 1970, though, merely recapitulating the basic design would get them nowhere--it was clearly far too expensive for sustained use--but an all-new design would require much of the NASA budget and might not be ready by the time the existing stocks of Saturn IBs were depleted. The concept of the Saturn IC, a significant modification which yet used mostly existing Saturn hardware, broke into this logjam in late 1970. It had been noted that the F-1A, a relatively modest upgrade of the existing and highly successful F-1, had a greater thrust than the cluster of 8 H-1s used on the first stage of the Saturn IB, and a considerably larger specific impulse. Combined with a modest upgrade to the S-IVB second stage, this would allow a rocket using a single F-1A as the first-stage engine to lift a greater payload than the Saturn IB, especially if the cluster design of the first stage was replaced with a lighter monolithic design, while being considerably simpler in design and cheaper to fly. The idea of the Saturn IC quickly gained acceptance by the agency, and by 1971 development on the new first stage was beginning at Michoud, with first flight expected by the middle of the decade.

Finally, there was the issue of logistics and station resupply. It was quickly realized that, while Skylab A itself would probably not need much resupply, Skylab B and any future stations would. The sheer mass and volume of supplies needed--everything from film for cameras and telescopes to mail for the astronauts--made Apollo flights a poor way to provide this service. They were burdened by having to carry a crew, the limited available volume within the CSM itself, and the unwillingness of the still mostly-pilot astronauts to "deliver milk". Thus, thought turned towards developing some type of autonomous vehicle that could be launched by the Saturn IC carrying a substantial amount of cargo and supplies to orbit, then rendezvous and dock with Skylab without needing a crew on board. As analysis slowly proceeded, it gained the name "AARDV," for Autonomous Automated Rendezvous and Docking Vehicle, but was quickly paraphrased to "Aardvark," and began to take shape. A suitably modified Block III SM would be used as the "brains and brawn" of the vessel, responsible for on-orbit maneuvering, while a large pressurized container would replace the CM to store cargo. While this pressurized container would not be able to reenter, it was soon recognized that this would allow the easy disposal of trash, allowing the use of the oxygen tank of the S-IVB as additional pressurized volume on Skylab B.
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  #17  
Old September 10th, 2011, 03:34 AM
Shevek23 Shevek23 is offline
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What can people say about the economics of space launches in terms of--how much of the cost is the rocket structure, versus the cost of the fuel itself?

Both costs would tend to be brought down by more frequent launches of a given type of rocket (though fuel costs would rise along with energy costs in general). So the question is, in say a Saturn V, or 1B, or the ATL 1C, would the dollar cost of the one-shot rocket structure itself (tanks, engines, electronics etc) be a large or small price of a launch compared with the fuel cost that must be burned up whether the craft is disposable or reusable?

The higher the proportion of the fuel cost to structural, and the more the latter cost is subject to coming down with large production batches and incremental improvements conserving as much as possible the utility of the existing infrastructure, the less attractive developing a reusable system is versus simply continuing with disposable systems.

Of course the teaser OP of this thread already established the "Grass is Greener" theme! No matter if the total tonnage the USA sends into orbit and beyond after 1970 is 5 or 10 or 100 times more than OTL, people there will still be sighing over how much better it would have been in a timeline with a Shuttle!

And the other side of the "fuel is the big cost" guess is, economies of scale will only take one so far--to have 20 times the orbiting tonnage, you might not need 20 times the expenditure, but it might still have to be 10 or even 15 times the total budget layout of OTL.

As always, the big problem with any "more operations in space" timeline is to answer the question, "Why go there?"

The coolness is not in doubt! I find the Skylab II very exciting--I guess the thrill of reading about it, and the Saturn 1C (with the implication of an open-ended series of incrementally improved blocks, and clusters, the gradual evolution of more and more capability as long as Congress keeps cutting checks...) was what inspired me to write something.

But having come up with this excuse to bump the thread and encourage it, I still want to know--what percentage of the total cost of the world's space programs has in fact been the cost of the fuel? ("fuel" cost obviously including the cost of synthesizing some sort of storable oxidant or liquefying oxygen of course!)
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Old September 10th, 2011, 01:26 PM
Workable Goblin Workable Goblin is offline
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To answer your question, Shevek, fuel is a pretty minor component of launch costs. Most launch vehicles (IOTL) use kerosene and liquid oxygen for their first stages, which as you can imagine are both pretty cheap (kerosene being basically pretty similar to jet fuel, and industrial atmospheric distillation being practiced on a large scale for various purposes). Nitrogen tetroxide and the various species of hydrazine that are used are a bit more expensive, if only because they require more specialized handling (being very, very toxic), but not enormously so. They do need to be extra-pure for launch vehicles, but this doesn't involve a huge change in price.

Or, to put it another way, the Space Shuttle costs something like half a billion dollars in marginal costs per flight, and has ~800,000 gallons of propellant. For propellant to dominate its launch costs (meaning that over half of the marginal costs result from propellant), each gallon of propellant would need to cost on average $312/gallon, which is something like the cost of fine alcohol. It's not very reasonable for an industrially-produced product with no "status" benefit.

EDIT: Oh, and I should say on the "more operations in space" thing...at this point, at least, there really aren't. Yes, we're picking up space station operations, but we're totally dropping Space Shuttle at the same time; so we'll see some more activity in the 1970s, but a bit less in the 1980s, maybe. It's less "more operations" and more "shifting around how much was done OTL". We do have, I think, a fairly plausible setup for why in the '80s (and perhaps beyond?) there might be some more activity, which you'll see when we get there.
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Old September 15th, 2011, 04:26 AM
Workable Goblin Workable Goblin is offline
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Okay, it's Wednesday again, and since e of pi hasn't put up the next post yet, I'll take care of it. In this post, we take a bit of a detour into robots--I promise that you'll love it, though.

Eyes Turned Skyward, Post #4:

"Life on Mars? The possibility might seem outlandish. As we have seen, Mars is many times colder and drier than the Earth, and it has only a thin atmosphere to protect it from the harsh environment of space. Certainly nothing like Barsoom or Lowell's vision can be found there. But there is a way. Microorganisms, living under the surface, protected from radiation and cold, only coming to life when conditions are right, much like certain plants found in deserts around the world, could yet survive on Mars, remnants of a wetter and warmer past... Wolf Vishniac has worked on the problem of finding such life, if it exists, for over a decade. For the Viking missions to Mars, he devised a simple test--the "Wolf Trap". Simply place a sample of soil in a habitable environment--warm, accommodating, and full of nutrients--and see what happens. The Viking missions to Mars each carried one of his "Wolf Traps" along with other experiments...Unfortunately, while the biological experiments all indicated that there might be some form of life, the chemical experiment indicated that there were no organic materials at all in the soil...One hypothesis is that there are only a very few thinly spread organisms encapsulated in thick protective spores. Such a population would be almost impossible to detect chemically..."

--Carl Sagan, Cosmos: Voyaging the Universe

"When Pioneer 11 entered the Saturn system, many wonders awaited. None, however, were more peculiar than the moon called Titan. The only moon in the Solar System with an atmosphere, it is eternally shrouded in thick haze, much like Venus except far colder...In fact, Titan seemed so odd that the committee in charge of the trajectory for the Voyager probes had to make a decision. We had two probes that could be redirected to fly by Titan, Voyagers 1 and 2. However, those were already supposed to use the boost provided by Saturn to fly on to mysterious and distant Pluto. If they were redirected to Titan, that would be impossible. Eventually, it was decided to fly Voyager 1 by Titan but let Voyager 2 fly on to Pluto..."

--Carl Sagan, Cosmos: Voyaging the Universe

While the shock of falling budgets was partially mitigated by the relief of falling costs as the Apollo program wound down, even the development of the Saturn IC and the Block III Apollo still consumed large amounts of money, and so tremendous pressure was placed on the less prominent unmanned programs to cut costs and fit in with existing budget allocations. Several programs, most notably the OSO series of solar telescopes, were canceled outright, with the OSOs being the victim of the solar-physics orientation of Skylab A. However, many programs survived (if damaged in the process), and went on to become legendary examples of unmanned exploration.

While the Mars Voyager program was already effectively dead, having had its budget axed in 1968 and in any event relying on unavailable Saturn Vs for launch, planetary scientists were still fascinated by the Red Planet, especially after Mariners 6 and 7 flew by in early 1969. Though these two probes combined still missed almost all of the most interesting features of the planet, the data returned was still curious enough that scientists pushed for a more ambitious project in the years ahead, something more like Voyager's orbiter-lander combination to directly investigate Mars' surface conditions. Even under the straitened circumstances of NASA at the time, they were able to easily get support, and a scaled down version of Voyager was planned for the 1975 launch opportunity. Instead of Saturn Vs, there would be Titan IIIs, and instead of Surveyor-derived landers there would be specialized (and lighter) vehicles, but two probes would still be ready by that launch date, with a special focus on biological experiments. Finally breaking the plague of Mars probe failures, Vikings 1 and 2 were both highly successful, with the former touching down at Tritonis Lacus on July 4th 1976, a perfect celebration of the nation's 200th birthday. Both survived for years on the surface, with the orbiters producing the first detailed global maps of Mars on their own multi-year missions. Even today, new analyses of the reams of data returned by the probes produce new research papers, making them one of the most scientifically productive unmanned missions ever launched, surpassed only by the second major unmanned program of the 1970s: the Voyagers.

Scientists at JPL, meanwhile, had realized that the forthcoming decade presented a golden opportunity for studies of the outer solar system. An exceedingly rare planetary alignment, termed the 'Grand Tour', would allow relatively modest rockets and a relatively small number of probes to perform flybys of all of the outer planets. They therefore proposed to do just that, using four large, expensive probes to study all five worlds, perhaps allowing more detailed orbiter missions at some future date. This, however, was a bridge too far for NASA. Each probe would massively dwarf Mariners 8 or 9 in cost, and the strain of winding down the Apollo program to its new Earth orbit mission while undertaking even the limited development of the Saturn IC and Block III CSM were too much for such an ambitious planetary program. Eventually, their mission was scaled back to the more limited two-part Voyager program, consisting of two Mariner Jupiter-Saturn probes (launched in 1977) and two Mariner Jupiter-Uranus probes (launched in 1979). In total, this would be a far less ambitious mission than the original Grand Tour or TOPS proposals. However, JPL had not entirely given up on the possibility of expanding the mission back towards its initial configuration, even if Headquarters didn't approve, and had designed the missions to hit the launch windows planned for the original Grand Tour configuration. Coupled with a certain degree of over-engineering, extended missions which would allow flybys of Neptune and Pluto would be relatively easy and inexpensive to conduct, and program scientists were confident the money would be found when the time came. As the 1980s progressed and NASA's budget expanded, this confidence was fulfilled, and the Voyagers went on to survey all of the outer planets.
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  #20  
Old September 15th, 2011, 12:27 PM
Workable Goblin Workable Goblin is offline
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Bump--it hardly seems fair to put up a post and then have it sink to the second page before anyone can actually see it.
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