Shevek, if you mean the red cylinders next to the SRBs, then if you look, they aren't on the Heavies or the M02. If you mean why the core stage changed color to orangish, it's because I think they'd switch to foam insulation with the core re-design vs. the legacy Saturn-style TPS. For the record (because I think it's nifty), the N2O4 wsn't used to control a nozzle. rather, when injected through valves in the nozzle, the N2O4 detonated, shaping the plume. this avoided the difficulty of gimbaling an SRM.
I didn't actually notice any red cylinders anywhere, and I assumed, wrongly, the orange stuff was just illustrative highlighting; I didn't realize it was a real feature of the rockets.
Don't have my spreadsheet in front of me, but it's about a 2 ton difference, yeah. A slightly expanded SM or MM is a pretty likely use of the margin, but they won't have it available until about '84/'85. Until then, they're stuck with "just" the basic III+, which is coming online in '80...
Quite. Any more would need a major change to the outer moldline--a scale up, a change in the sidewall angle...basically a new capsule.
I'm getting greedy I guess. Here you've gone and increased the human payload of the 1C by nearly 70 percent and now I want whole busloads of people lifted up at one go! I guess we should just kick back and assume that five people going up at a time is plenty improvement on OTL-sure the Shuttle could carry a few more, but not economically, whereas if we are satisfied with just 5 each batch of them goes on a mass-produced and thus increasingly cheap (and probably, increasingly reliable, if people don't get complacent and sloppy) system, so more launches for the same dollars, even granting that nothing is getting reused.
Another direction to improve things in of course is to start reusing the standard III+ capsules, by careful analysis of what parts get dangerously stressed during reentries, and redesigning the capsule to replace those parts and reuse the rest. Obviously the ablative heat shields have to replaced each time but I don't see a problem with designing them as a bolted-on outer layer that they just unbolt and discard and snap on new ones.
If I start thinking about trying to reuse SMs we'd be getting into dangerous territory so I won't. Economy there is again a matter of a standardized frame with modular specializations for each mission, and since I suspect most missions are just, um, shuttling, to an established space station in standard orbit, the missions will generally be the same, so an absolutely baseline standard can be made in production lots, with the occasional upgrade or downgrade costing somewhat more.
Mission modules on the other hand--there I think when an Apollo III+ departs a space station to return home, it makes no sense to take the MM, even stripped of supplies for the station, and yank it into a disposal orbit--except of course when the MM is now full of trash that needs to be disposed of. But generally they could just shunt it over to some storage zone--an orbiting junkyard essentially--and figure sooner or later they can strip it down for useful parts or melt it down and reuse it that way. The station will be accumulating mass with each MM that comes to it.
I was wondering if it would make sense to waive the MM on missions that are just shuttling astronauts to the station and back, but I guess not. Cutting down the mass means we'd need a bit less propellant, but that won't translate into serious savings--might as well spring for the full fuel load, get full use out of the fixed weight of the rocket stages, and then use the extra lift to deliver supplies to the station if nothing else. Also there is the safety issue--the MM provides much-needed living space. It might not be needed if everything goes smoothly, but if something goes wrong it's there to keep an undesired, unexpected delay from turning into a disaster. So MMs all around, at least on all launches of more than three astronauts.
Free-flying Apollo III+ missions will of course have to either abandon their MMs in orbit, adding to the problem of space junk (in a fairly tame form, it isn't a cloud of debris, it's a single concentrated trackable object--but sooner or later it will either deorbit unpredictably or
become a cloud of debris!) or else use delta-V to decisively deorbit it. So no reusing those. Not unless it makes sense to put a rocket on it and send it by remote/automated control to join some established station where they'll put it in the junkyard.
If and when indeed. Another interesting thing might be to note that the Heavy has a TLI capability slightly more than the M02. In rough terms, anything an M02 can put into a 185x185 28.5 degree orbit (26 tons), a Heavy could put through TLI. For instance, a Block III+ CSM with enough of a SM stretch to be capable of LOI/TEI. But that's a matter for other posts in the future.
I was not thinking of transorbital stuff, not much anyway.
Manrating the Heavy should be easier than a new design or one evolved from a missile or satellite-launcher, but I guess it isn't a slam dunk. There will be a certain, hopefully low, but nonzero unfortunately, probability a standard first stage will fail; the probability the whole three-stage triplet will work OK will be no greater than the cube of the probability one alone will work smoothly. We are cubing a number very near to one, (1-e) where we hope e is a very small number, but the probability the Heavy first stage will go OK is (1-3e) approximately. And then the extra bric-a-brac involved in physically linking together three cylinders side by side, coordinating three rocket engines that aren't in a tight cluster but strung out some distance apart, and so forth lowers the number a bit more. Whatever the margins actually are on the M02, they will be lower on the H0(n). Of course "e" is just an educated guess, one can present rigorous arguments restricting it to a certain range--assuming everyone does what they are supposed to do, no one gets drunk, drops a wrench and forgets they did it let alone logging it, no one violates pre-agreed weather guidelines and launches in a cold snap out of parameters
eek: ahem!) or with winds beyond them, quality controls are maintained and not allowed to lapse, etc. One can even try to factor those into safety factor estimates and then still be blindsided by a genuine act of God. Or deliberate malice.
But since a Heavy launch is guaranteed to be more risky, if only by some wispy fraction of a percent, than a standard single-first stage launch, programs will evolve toward it for manned flight only for a very good reason I guess. Another reason to be very patient.
For now. Thanks for the hint of hope though!
DoD gets most of what it wanted OTL from Shuttle from the two ELVRP II rockets--cheaper cost/flight and larger payload capacities. In the end, I suspect that the mission they had that dictated Shuttle's added cross-range requirements--the one-orbit polar launch and landing at Vandenberg--isn't enough here to drive an entire spacecraft dev program by itself here.
In vague generalities, DoD insisted on cross range because launch into polar orbit inherently means that one orbit later, the launch site (which is ideally the landing site--well, certainly for a reusable craft, which you don't want to have to ship to a distant launch site, but it wouldn't be crazy for DoD to argue they had a general need to keep Defense business restricted to Defense sites) would be guaranteed not to be there for a reentry after just one orbit. Depending on the exact nature of the orbit it might be days before Vandenburg came around to being in range again as the craft was approaching the reentry go-point. Well yes, but why exactly could they not plan orbits that had more convenient timing and why not be patient?
The only specific mission I've seen outlined that would require them to do a quick run up to orbit and then return to launch base, and might not allow the convenience of deliberately shaping the orbit so that while Vandenburg might not be in range after one orbit, Hawaii or Anchorage, Alaska would be--was the harebrained scheme of wanting the capability of being able to intercept a foreign satellite, grab it and take it back down to Earth with them!
Well, if some unnamed foreign power--lets make up a silly, improbable anonymous name in no way resembling anyone living or dead and call them the "Lussians"--were to take the position that that was legally speaking an act of war, I wouldn't call them crazy. They'd be on very firm ground indeed calling it piracy. And if they, guessing Americans who talked about wanting to do this had spent money to actually be able to because they might someday actually do it, were to outfit their craft with booby traps like say a motion-sensor detonated high explosive bomb, perhaps one with a 10 minute delay timer--well, it might be a little uncultured of them but within their rights if they want to expend delta-V on that--besides, any satellite the Defense/Intelligence cowboys would rustle like that might rate a self-destruct device just on general principles.
But that's the kind of thing they said they wanted to be able to do. And who knows what more sensible if chilling, but perhaps, once one's blood has been chilled, reasonably security-related real purpose this might be a bit of misdirection to cover? But right or wrong, this was just the kind of thing the Reagan Admin would champion, at least in principle.
So I am not sure the military would not think up some mission that did require military astronauts in space, and perhaps the ability to retrieve objects from space (I hope not stealing someone else's satellite, but whatever). So say they do a double-pad launch from Vandenburg, one rocket carrying a manned III+ variant with a mission module including a grabber arm, and the other being an empty reentry capsule they can stash whatever large object they are retrieving with a transstage. They get the object, whatever it is, remote-control the other capsule (a much modified Aardvark, essentially) over and put it in, then send it on its path down to get retrieved on the ground, then go home.
Or who knows what else they might decide to accomplish with a couple, or up to 5, military astronauts and the equipment one puts in an MM along with essential supplies?
The point here is, the rockets are off the shelf, they just grab a few from stocks. And Apollo III+ are turning into commodities, they don't have to actually design one, just requisition it. All they have to design is the MMs plus of course exotic stuff like retrieval shells, if that scenario ever actually comes up.
And I suppose it might if say a treaty with, oh let's choose someone real since this is less inflammatory and invidious, the Soviet Union for instance, specifies both nations are "trusting but verifying," and have the right to inspect the other's installations, in the case of satellites by choosing one at random and examining it closely, to make sure the other party isn't illegally weaponizing space for instance. Then it wouldn't even be a black budget sort of thing, retrieval capsules might then be specified and contracted openly explicitly for this purpose. (When an inspection amounts to testing to destruction, I suppose the nation that yanked the other guys' satellite would owe them compensation so they can launch another one--assuming no violations are proven of course! OTOH if they put a bomb in it, that would be very nasty indeed--but in this scenario instead of blowing up a reentering Shuttle it blows up an unmanned capsule--destroying whatever evidence the inspectors wanted to present, but also making their case for them.)
One benefit of relying on these sorts of evolved system instead of some grandiose one-size fits all thing like the STS is of course that when some odd specialized need comes along, one can tailor the system to it. The big benefit is, economies of scale cheapen the basic components. So DoD is mainly using standard units, supplemented by specialized stuff. The standard stuff comes cheaper than OTL.
I don't suppose they'd reinvent STS here. DoD might want to get around at this stage to developing DynaSoar though, if it were essential to return the crew to a secure site, or if they wanted to retrieve something small enough to fit in place of an astronaut.
You have convinced me that most of the time, a simple capsule return will be cheaper and work just fine, and maybe this means no one ever develops an actual spaceplane
Then again, that satellite-snatching team--they can reenter in a capsule but might have to go to a splashdown in the middle of the ocean rather than return to base. Why shouldn't they develop cross-range, if they have to cover contingencies that are unpredictable in detail?
The point here is instead of forcing everyone to choose between all having to use capsules or all having to use the same overengineered, oversized spaceplane, now the guys who want the spaceplane occasionally only have to design that, a small spaceplane for a handful of crew only, with no Main Engine rated to take them and a whole lot of fuel to orbit, no cargo bay flying empty most of the time--just finish the job almost done with DynaSoar, and if they want to be retrieving stuff massing tens of tons, then spring for developing say a lenticular shell that can open and close like a clam and doing two launches.
If everyone else is good with planned launches that can use economical standard capsules and has no need for hauling stuff down from orbit, these options are just exotic--and expensive!--variations paid for out of the military budget.