It occurred to me that while the Chinese are waiting on the development of Long March 2D, they can still expand on the limits of the Shuguang 10 mission by launching not one but two Tianjia modules. Of course that imposes the logistical overhead of having to dock not once but twice; either the two modules are remote-controlled to dock with each other unmanned, then the Shuguang mission comes up to dock with the pair as usual, or else the Shuguang comes up, docks with one, then the second pilot moves back to a second docking station at the back of the first Tianjia module, and using maneuvering thrusters built into that module along with the forward set on the Shuguang, they maneuver the whole massive stack onto the smaller second module. Or third option, one of them or both spacewalk over to the second module after a routine dock to the first, and operating controls on it, dock it to the assembly. That last one is pretty damn scary for a variety of reasons and probably would never be considered seriously of course!
Any way you look at it, it is not easy. I can see the wisdom of simply waiting for the next iteration of Long March, which after all would allow not only a larger version of Tianjia, but a larger Shuguang C. In the McDonnell Gemini proposals, the Gemini was after all supposed to be space tractor as well as taxi.
On the other hand, while Tianjia-Shuguang based temporary stations do have a worthwhile set of uses of their own, i have to figure that the Chinese mission planners, like the designers at McDonnell, have sold the program as something that extends beyond this capability, to an open-ended program for larger and more permanent space stations. And unlike the American designers, who knew for a fact that launch vehicles much larger than even Titan III were in the works and would presumably become operational, the Chinese may anticipate that something orders of magnitude bigger than current Long Marches might be developed someday, but the only way to make concrete plans is to assume only gradual, incremental evolution of their capability.
For what it is worth, when I was kludging around with various Silverbird Launch simulator models of Long March type rockets, it seemed to me that the first stage was rather hefty and robust compared to the second; that there is considerable room for growth just using bigger second stages and payloads. When they run into hard limits of the first stage's installed thrust capability, adding on some auxiliary strap-on boosters, either solids or something based on additional single YF-20 series engines, would again allow some more incremental progress.
So--while they can hope to add on 20, 30 or 50 percent to their current maximum launch masses, there is no current plan (that you've disclosed anyway
) for a radical new heavier launch vehicle. A few tens of percent more can relieve current over-tight margins a bit, but won't radically change the nature of what the Long March system can do.
So the only way forward, aside from growing Long March a bit, is to get on with learning how to gang together an arbitrarily large number of Tianjia modules. Three units total, counting the Shuguang as one of them of course, is a much bigger challenge than two, for the reasons I sketched above. Either they have to master automated, remote-guided docking procedures that don't require astronauts on hand to do the driving at all, or the separate modules must each have quite a lot of maneuvering overhead in the form of propellant and sets of maneuvering jets that become redundant as soon as dockings are successful. (Presumably, with a little complication, a standard set of plumbing and interconnections can be used to siphon off remaining propellant from modules in the middle of a chain or network of modules and refill the tanks of ones on tips, where the propellant would be useful. And not so incidentally, reduce the hazard the stored hypergolics pose, if the crew can then concentrate activity mostly in the emptied middle modules). And then the crews have to become adept at maneuvering the large constellations of Tinkertoy modules they have managed to jockey together to swoop down on (really, creep up on) small additional modules.
Or I guess in lieu of my alarming spacewalk option, the crew of a Shuguang can undock from the large partially assembled station, fly over to a new module, dock with it, and fly it as usual to the larger object and a suitable docking port on it.
It does make me wonder whether they are going to rethink the docking mechanism, to make it more androgynous, so that any port can dock to any instead of having to think out carefully the gender of each port one designs and launches!
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Something else has been bothering me. Can you elaborate on the Chinese landing recovery plan? OTL when China has finally nowadays gotten around to a manned craft, they based it on Soyuz, so its return capsules are designed to come down on land, which serves Chinese security interests really well--the Shenzhous presumably start aerobraking over Central Asia and are aimed so that their westernmost probable landing site is just east of the western border, in the wastelands of Xinjiang. That way the most probable site is safely in the wilderness they control, and the farthest east is still very far west of very densely populated land.
But Shuguang like Gemini cannot safely plan to come to rest on dry land; it requires a body of water to splash into. If the Chinese had somewhat more mass to play with than the Americans with their Titan IIs, they might add in extra parachute area (if that works--I suppose trying to slow descent speeds with bigger chutes is a mug's game because the more it lowers the terminal velocity, the less effective a given area is, so just doubling up on parachutes might be very cost-ineffective) or develop some sort of auxiliary landing rocket a la Soyuz. Given that there is a plan to develop Shuguang's heat shield into a hatch, I don't think a single solid rocket in the dead center of the heat shield would work well, so they'd have to do something more like TKS, with a retro-rocket attached to the nose, or as with TKS on the chute rigging lines, I'd think.
But anyway the Chinese don't have a positive credit of mass to work with, they have a deficit to work around, so perforce they are going to have to fall back on recovery into bodies of water.
Which raises a lot of questions, that I tried to beat to death in a long draft of another post.
Would you please anticipate them, and tell us the limits and constraints on the precision of a Shuguang landing--especially an emergency return such as Shuguang 11's--that govern which bodies of water they aim for? I'm assuming the uncertainty about the precise splashdown location of even a planned and prepared landing, with extensive sounding of weather conditions along the anticipated entry path and so forth, is so great that they must aim for a point well offshore China, in the Pacific.
Here's a map of the Economic Exclusion Zones the PRC claims today--
--but note that the modern conventions about a 200 mile extension of partial sovereignty off shore date from the 1980s; in the 70s I doubt anyone outside of the PRC would be so generous as even to grant them the limited economic exclusion rights they now enjoy even in the dark purple area that is contiguous with their shore--the wider claims in lighter color or merely outlined are strongly disputed even today. Anyway the Exclusion Zone concept refers to rights to exploit oceanic resources, but does not remove these waters from international high seas. Which means ships of foreign powers conventionally still have the right to intrude on these waters, to transit or loiter as they please.
I would imagine a Shuguang's landing footprint of probable locations is much longer than the 12 mile limit modern law grants as sovereign national waters, so the aim must be for a point that may or may not be within the EEZ but anyway are waters where foreign vessels may freely congregate.
And that means the People's Liberation Army Navy (don't look at me, I'm not the one who comes up with a Navy that is part of an Army and frankly names it so
) or one of their other coastal forces such as
these guys must not only send out some kind of craft to actually come to the aid of the landed astronauts and attempt to salvage their spacecraft as well, but meanwhile also discourage loitering gawkers. With Nixon going to China around the time of the first successful manned missions, the grave threat the USN would have posed should we have taken a frosty line is largely averted and in a situation where the Chinese actually would want help, converted into a valuable backstop asset. With relations correct and thawing between the powers, the Americans might still want to investigate Chinese space operations as closely (and suspiciously) as they can, but they won't interfere and will help if asked to. The danger here is losing the prestige game if they have to ask, and the risk that the Yankees will discredit Chinese ability by being overhelpful.
With the US State Department more or less in the PRC's corner all of a sudden, while the USN might harbor many officers and sailors who remain skeptical of the wisdom of cozening up to the most populous and fanatically Communist nation in the world, since it is Nixon and not some presumptive commie-symp liberal who is cuddling up to Mao and his successors, the Navy will follow orders and be as helpful to the Chinese space program as Beijing allows--though perhaps some of them will be more than thrilled to interpret their orders so as to embarrass the ChiComs!
Without the quasi-protection of the USN though, it is hard to see how the Chinese proposed to keep their astronauts completely safe from the Soviet Navy. They too, despite the extreme tension that had arisen in the Sino-Soviet split, would probably be under orders to do nothing that would be an open act of war--but also understand that any opportunities they could take to embarrass the Chinese would be approved in the Kremlin too. With the Americans cozying up to China, the danger that Soviet vessels might seriously gum things up recedes considerably of course.
So--now that Nixon has gone to China, and the USA appears to be on the course that in fact it has kept to for over a generation now of rapprochement and normalization of relations with the PRC, the Shuguang program can presumably rely on the waters east of China being available for their landings without interference. But how confident could the early mission planners in the early 1970s have been than their capsules would not be pirated by hostile capitalist or Communist powers routinely?
They had to risk it of course, but it would be helpful if you could describe the space and time scale of a Shuguang landing so that we can judge how much of a risk they were running when the Americans were presumed to be hostile, and perhaps liable to acts of piracy against the People's Republic.
Also, a description of the logistics of Shuguang recovery is in order because the PRC has very different kinds of resources than the Americans did. The USA had the US Navy, deployed with bases all around the world, and dozens of aircraft carrier groups, each a many-ship task force that routinely deployed large helicopters as well as many specialized auxiliary ships, and carrier decks that could launch and land squadrons of fighter planes.
The PLAN has one single aircraft carrier
today. It had zero in the 1970s, and my reading at wikipedia on the particular classes of ship they did have (the heaviest being destroyers, not even any cruisers) suggests that very few of those could deploy even a single helicopter in that decade.
I suspect that recovery of a Shuguang would begin with intensive planning and tracking of the actual entry, to try to land it as close to Chinese shores as possible without risking it actually coming down inland somewhere, with probably fatal results for the crew and a fair likelihood of killing or otherwise hurting a fair number of bystanders on the ground too. Supersonic fighter planes would be dispatched from shore bases to attempt to spot and locate the capsule and pinpoint its landing, while keeping an eye out for foreign intruders. The fighters that find it would loiter in the region, in line of sight of the floating capsule, to deter intruders and keep an eye on the capsule until other resources can arrive. The Chinese had, in the 1970s, some old
Beriev Be-6 flying boats--around this time, their Soviet-made radial engines were starting to give out and some were re-engined with Chinese made turboprops instead. I suppose one or two of these would be dispatched next, perhaps sitting already near the predicted middle of the landing footprint. They could get there faster than helicopters, even assuming the Chinese had choppers and the ability to land them on nearby ships. The flying boats would put down and one would sidle up to the capsule to recover the crew, in the style of WWII USN "Dumbo" PBY's in the Pacific. They might send two so that one can keep watch over the capsule while the other speeds the crew back to shore. Then a seaborne vessel of some kind, possibly a destroyer, maybe something smaller, comes up and simply lifts the empty capsule out of the sea with a crane, and protected either simply by its PRC flag or perhaps by other armed vessels of the PLAN, heads for port while any other PLAN vessels assembled to secure the landing zone disperse to their normal patrol regions. The fighter planes probably had to return to base some time before, as soon as the first flying boat landed and took custody of the situation, though in a tense situation they'd be relieved by other fighters circling around to intimidate any possible evildoers lurking about--anyway now they can go home, or rather remain perhaps as air cover for the returning vessels.
This is somewhat different from how the Americans did it of course. And if some rival power such as the Soviets were bound and determined to interfere, the Chinese would be risking a nuclear war to oppose them. American support makes it unlikely the Soviets would dare, but also would make the Americans queasy. In the modern geopolitical context, I do not doubt the Chinese would be able to deploy enough force of the right kind to discourage any shenanigans, but in the 1970s they would be much less credible a few dozens of miles offshore from their massive land power.
So it is no accident I suppose that the modern Chinese, despite their much better position on the high seas today, have instead chosen a system that allows for land recovery, which relieves them of these kinds of headaches.
I would think then that Shuguang designers are under some pressure to reserve part of any mass they can add to their system for alternative landing technology of some kind that would allow Shuguang-C or later versions to be recovered inland, in the steppes and deserts of the far west, rather than in the foreigner-infested waters to the east.
