Good points. The temperature swing is the biggest engineering hurdle between the Artemis infrastructure and a successful Orion in my estimation, so it makes sense to go somewhere where you're guaranteed near-constant solar exposure, which also solves the second hurdle of power.
I wasn't sure how precisely you would have to land every lander so they are in constant sunlight, so I looked up an analysis of SELENE altimetry data, and it turns out that you would have to balance on long stilts to get continuous light, even at the sunniest spot on the moon -- there are no areas of continual sunlight on the lunar surface. Long stilts are almost definitely not in the equation, so a precisely-targeted polar lander would have to last 40-50 days in shade a year (less on the North Pole at the north rim of Peary, more if you miss an optimal spot), which I would wager are consecutive since the sun would be dipping below a generally-flat horizon. That's longer than the 14 anywhere else on the moon, but you get only one deep freeze a year, which could simply see evacuation of personnel until a later administration sends equipment to keep the station from having to go gentle into that good night. You also get ice, for sure, if you choose the Shackleton rim.
So, the question then becomes what type of cold can we design our systems (and consumables, since the base will store food for several trips) against better -- short and frequent, or long and infrequent. Surviving the long polar night may require the soonbase to be able to deactivate and sleep through it (with no personnel on station, of course). Meanwhile, the 14-day lunar nights can already be handled by the hab lander, so continuous operation would only need the extra power to keep the system toasty for human occupants.
A heating system would also work on a polar mission, since fuel cells could be charged over a much longer timeframe, which might be enough to offset the longer time the full heating will need to last. You'll be tripling the fuel cell mass (well, more, depending on fuel leakage), but it might still be the most viable option even considering that, since not all the cells need be sent there on the first mission.
The third option is to space out launches so the soonbase consumables will last less than a year. Then, a polar soonbase never needs to see the darkness at all. This is the simplest option, with minimal engineering needs (just hardening everything to last the whole time, with a shorter target lifetime than multi-year mission profiles), but needing the highest budget (all launches in one year, instead of spaced out), and lowest in terms of returns, so we likely won't see this unless bad things happen on the engineering side and we decide we have to launch at least something.
You could actually use all these approaches in the same design; with a supply lander that can sleep through the long night, and later shipments of extra fuel cells and solar panels to extend the base to continuous operation.
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You have to go where water is if you have limited ability to transport Mass to the surface. With access to water you can not only minimize the need to bring water to the Moon. You can also extract Hydrogen and Oxygen from the water and with the proper equipment get more fuel for the fuel cell. This allows you to then survive the lunar nights. If you can then land a pressurized lunar rover that can cover long distances on the surface you can then explore a wide area around your lunar base. With water, inflatable habitats and the right equipment you could even expand your base site enough to start growing food on the surface.
So, I'm really enjoying this lunar base site discussion. It's very interesting to see everyone wrestle with the problem of where to put it. I've been staying quiet since I was curious to see where people's thoughts would converge without Workable Goblin or me biasing them, but as a consensus seems to be emerging I thought I'd point some information that may be relevant to discussions of power at polar outposts.
Essentially, using laser altimeter data, NASA's been modeling polar region illumination and night length IOTL for much the reasons we're talking about here. This is an example of the results, in this case for Shackleton. Note that "dark period" is spread out over the year in very short nights, which is convenient! For some of the best accessible sites, the night is as short as 3-5 days, which is quite reasonable indeed. These sim results are also rather fun to watch.
Essentially, using laser altimeter data, NASA's been modeling polar region illumination and night length IOTL for much the reasons we're talking about here. This is an example of the results, in this case for Shackleton. Note that "dark period" is spread out over the year in very short nights, which is convenient! For some of the best accessible sites, the night is as short as 3-5 days, which is quite reasonable indeed. These sim results are also rather fun to watch.
Given that the hab landers already use regenerative fuel cells (though I can't recall if they're water cells), and given that "dirty" ceramic fuel cells exist which can process impure Hydrogen and Oxygen, I wouldn't call it too much of a stretch to have dirty regenerative water cells which can take lunar ice that's been melted (using solar reflectors should make that cheap) then run through a particle filter. You could even optimize the dirty cell for electrolysis, and use a clean, possibly-more-efficient design for the power generation and regeneration.
Great find! It looks like I miscalculated the day-night cycle, and my previous assertion of contiguous 50-earth-day lunar night only holds at the lunar poles, where the ecliptic never moves in the sky. Thus dies my last real worry with a polar base.
Looking at the maps here, it seems the section of rim around (-3, -10) on the maps is the ideal location for both sunlight (being the highest part of the rim) and access to the floor, with the shallowest and smoothest slopes. I'm not too familiar with selenography so I can't say whether this is also where Artemis 9 went, but I think it probably was. If so, then the soonbase could, among other things, take a look at how LIFT is doing.
Speaking of which, was LIFT actually deployed on the crater floor? Given that the perma-night begins about 2 km down (or 4 downslope) from the target I'm assuming above, then they wouldn't have needed to go all the way down unless they had a good reason to. Same goes for the ice discoveries -- OTL studies indicate that the crater walls are much more reflective than the floor, meaning it's likely that there's some exposed ice in these more-accessible areas, which in turn means that the ice is generally much closer to the surface, which fits the results from Artemis 9.
4km direct distance is short enough that you could string a power cable all the way from permadark to near-perma-light. You can keep your solar panels at the top, and set up all your fuel cells, cryogenic storage, and regolith processing right where the water source is. I was scratching my head a lot last night trying to figure out a good way to ship the ice upslope for processing (in large quantities, anyway -- samples, drinking water, and breathing oxygen can be carried up on rovers), but that isn't really necessary at all.
Of course, you can also string a cable down the whole 9km slope to bottom, but you'd need more cable and pylons, and a 4km cable, with some smart design, could be light enough to fit in the downmass of a later mission with enough to spare for a full regolith ice processor pilot plant -- dirty electrolytic cell, storage tanks, ice melter/filter, fuel-cell-powered dig rover and all. One thing you lose, of course, by putting the plant in permadark, is the free solar heating to melt the ice, since a big system of reflectors would probably be too much infrastructure for anything beyond a massive processing plant far in the future.
A note about the dig rover -- that's probably the riskiest part of the whole system, so it's conceivable that it would be replaced, initially, by a digging module that gets mounted onto one of the manned rovers already on the surface.
And this is just one possible engineering mission -- there's also the possibility of a movable infrared telescope as a successor to LIFT (since the risk due to moving parts in deep cold is decreased by the prospect of return missions), mooncrete experimentation, testing moon dust (with various degrees of processing) as a hydroponic inert medium, etc. On the lunar-science side I'm a little more blank, but I'm sure there's a wealth of things that repeat visits can do. As is, I'm more interested in the engineering of making the base more self-sustainable, since every gram of consumable (drinking water, breathing oxygen, return fuel, etc) that doesn't need to be shipped down is one which can instead be scientific payload (or further engineering infrastructure, of course).
Edit: The angle of repose of lunar regolith is 31°, which is also the rest angle of most of the crater wall, so it seems likely that roving around recklessly on the slopes will lead to avalanches. How did Artemis 9 deal with that? Was the switchbacking meant to keep them from moving down with the drifts of moon dust that they kick loose? IF so, it seems like rovers won't make an efficient long-term solution for shipping materials up and downslope. Power-line-pylons as above can be used to test designs for stringing up a ski-lift of sorts, so that seems like a likely solution. What's more troubling is the fact that this might make a robotic strip-mining operation impossible until a mooncrete-berm-avalanche-prevention system is proven out. That might not be such a bad thing, as the digging operation and water ISRU would leave a large amount of dry leftover dust, meaning mooncrete production and mooncrete requirements could scale together. Industrial use is definitely far away though, but I can see test mooncrete being used for this.
Speaking of which, was LIFT actually deployed on the crater floor? Given that the perma-night begins about 2 km down (or 4 downslope) from the target I'm assuming above, then they wouldn't have needed to go all the way down unless they had a good reason to. Same goes for the ice discoveries -- OTL studies indicate that the crater walls are much more reflective than the floor, meaning it's likely that there's some exposed ice in these more-accessible areas, which in turn means that the ice is generally much closer to the surface, which fits the results from Artemis 9.
4km direct distance is short enough that you could string a power cable all the way from permadark to near-perma-light. You can keep your solar panels at the top, and set up all your fuel cells, cryogenic storage, and regolith processing right where the water source is. I was scratching my head a lot last night trying to figure out a good way to ship the ice upslope for processing (in large quantities, anyway -- samples, drinking water, and breathing oxygen can be carried up on rovers), but that isn't really necessary at all.
Of course, you can also string a cable down the whole 9km slope to bottom, but you'd need more cable and pylons, and a 4km cable, with some smart design, could be light enough to fit in the downmass of a later mission with enough to spare for a full regolith ice processor pilot plant -- dirty electrolytic cell, storage tanks, ice melter/filter, fuel-cell-powered dig rover and all. One thing you lose, of course, by putting the plant in permadark, is the free solar heating to melt the ice, since a big system of reflectors would probably be too much infrastructure for anything beyond a massive processing plant far in the future.
A note about the dig rover -- that's probably the riskiest part of the whole system, so it's conceivable that it would be replaced, initially, by a digging module that gets mounted onto one of the manned rovers already on the surface.
And this is just one possible engineering mission -- there's also the possibility of a movable infrared telescope as a successor to LIFT (since the risk due to moving parts in deep cold is decreased by the prospect of return missions), mooncrete experimentation, testing moon dust (with various degrees of processing) as a hydroponic inert medium, etc. On the lunar-science side I'm a little more blank, but I'm sure there's a wealth of things that repeat visits can do. As is, I'm more interested in the engineering of making the base more self-sustainable, since every gram of consumable (drinking water, breathing oxygen, return fuel, etc) that doesn't need to be shipped down is one which can instead be scientific payload (or further engineering infrastructure, of course).
Edit: The angle of repose of lunar regolith is 31°, which is also the rest angle of most of the crater wall, so it seems likely that roving around recklessly on the slopes will lead to avalanches. How did Artemis 9 deal with that? Was the switchbacking meant to keep them from moving down with the drifts of moon dust that they kick loose? IF so, it seems like rovers won't make an efficient long-term solution for shipping materials up and downslope. Power-line-pylons as above can be used to test designs for stringing up a ski-lift of sorts, so that seems like a likely solution. What's more troubling is the fact that this might make a robotic strip-mining operation impossible until a mooncrete-berm-avalanche-prevention system is proven out. That might not be such a bad thing, as the digging operation and water ISRU would leave a large amount of dry leftover dust, meaning mooncrete production and mooncrete requirements could scale together. Industrial use is definitely far away though, but I can see test mooncrete being used for this.
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, polar seems most likely. There you'll have the maximum scientific return, while showing the advantages of a continued lunar presence, pulling water to the Lunar Society mill.
On the other hand, by setting near a lava tube, what advantages will you have, apart from showing that they are habitable?
On the other hand, by setting near a lava tube, what advantages will you have, apart from showing that they are habitable?
No worries, boris. I'm not advocating lava tubes any more. I had mistakenly thought that a polar settlement would have a longer night, which would make a lava tube a safer bet, but e of pi linked a good study above and I realized I'd made a calculation error. So I guess since I wasn't clear enough, I'll go ahead and say outright that my vote is with Shackleton, in particular, the location proposed in my previous post.
OTL's HOPE-X. I am satisfied.
Also, did you say H-I when you meant H-II again?
I also liked the "soonbase" method, all it takes is an extra lunar logistics lander.
By the way, if this timeline went on past 2015, when do you think the first Mars mission would be? Late 2020s?
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Apologies for the delay, but I sort of forgot that with Nixonshead still away, posting this week's image falls to me. So, without further ado, I hope you enjoy...
Yes, edited.
That's speculation that'd depend a lot on what happens later in Part IV, so for the moment I'm going to leave that unaddressed.
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I think that's possible if NASA plays its cards right, and is lucky (with a good economy, thriving private space industry, and a friendly administration). I think NASA has a real shot at getting a private-enterprise-hydrolox-refinery going on the Moon, and once that source of cheap fuel is up, everybody at NASA will be thinking the same thing: the solar system is their oyster. If one of their first soonbase missions sets up some ISRU test infrastructure, and the soonbase missions are stretched out over a few years, then by the end of the soonbase's life, they might be able to go home using fuel refined on the Moon. That major propaganda coup would warm Congress to the prospect of a NASA-run commercial competition for exploiting now-proven lunar hydrolox production. Even better would be the possibility of scoring this victory before the final mission, in which case the final missions could get the additional remit of smoothing the way to a commercial moonjuice solution. That could very well be a lifesaver, as the fuel transfer between base and lander will probably be a very tricky thing, and without astronauts on site it could be an abject failure. We have Northrop TransOrbital projected to come online likely in the early 2010s, we've had the Thunderbolt proving out RLV tech for a few years, we have and if the soonbase has moonjuice as a priority, we could have the whole regolith->hydrolox-storage part of the pipeline proven out by 2010. Assuming the the last few crew landers use moonjuice for return (well, almost certainly keeping extra margin just in case), they'd have the opportunity to test out various automatic fuelling systems, which, on top of testing in LEO and on Earth, might de-risk that part of the pipeline enough that it is no longer a tossup whether or not it will work. The rest of the pipeline is more or less TransOrbital but on the Moon, using lunar polar orbit, L2, or whatever works, I'm no rocket scientist.
There's gotta be a dozen whitepapers on this sort of stuff, it's time I stop yapping and get down to research. Thoughts?
Excellent job, Nixonshead. So TTL's HOPE has a single vertical stabilizer instead of two.
As always!
Which makes it look even more like OTL's STS and hence Buran than I guess OTL's HOPE would have?
That's what struck me most about the picture--since the angle obscures the fact that there is no crew section with windows and doors in the front, and there is nothing to give a particular sense of scale, it looks almost exactly like an OTL Space Shuttle.
I haven't been following the Japanese programs very closely but I was under the impression they have considered a very wide range of aerodynamic forms for their proposed reusable craft, including lifting bodies more like HL-20 (and hence Dreamchaser) which was the form a NASA campus actually chose the last time they reconsidered a reusable crewed orbiter in-house; other forms that are much more rectangular, looking a bit like a photon torpedo casing from the earlier Star Trek movies (like the one they bury Spock in at the end of WoKh say), not to mention yet other programs like Fuji that wind up with a conical capsule so flattened it is almost lenticular.
So I don't know if all of these were rival proposals to HOPE and the latter has always stuck close to a Shuttle-lite layout. I do notice that nowadays OTL when the Department of Defense shells out for unmanned reusable orbiters the thing they fly also looks more like a scaled-down Shuttle than any radical rethinking of the concept.
So--should I take from this that actually when all is said and done, the Shuttle Orbiter, however launched, was an excellent job of optimizing the layout of a horizontal landing reusable orbiter--a relatively thin compound delta wing housing a box with a tail on its back is pretty much the way to go?
Or if there are known drawbacks to this basic layout, what were the compelling advantages that made the Japanese settle on it? OTL, it's a tried and true form and that helps explain why people might choose it despite known flaws--it also has well-benchmarked characteristics people can design around with confidence from a generation of experience. (Including one unintended test to destruction
). Vice versa OTL some of our alternative forms might not be due to compelling aerodynamic advantages so much as the mere desire to break the Shuttle mold; here neither the useful nor constraining aspects of the STS legacy have any bearing.
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I then had this to add; over 12 hours later I saw I had not posted it, but unless my browser is being very weird, apparently it's still the next post anyway:
Now I'm looking at the image in Pipcard's signature link; from the perspective shown there the OTL HOPE differs from the STS Orbiter in other ways than number of vertical stabilizers. Its wing is relatively elongated and unlike the Orbiter its strakes enclose relatively more of the body, almost to the very front; the nose assembly seems somewhat different, more like a rocket nose cone and less like the airplane-like nose of the Orbiter; the body seems more cylindrical and less boxy.
All of these divergences from STS design might be present in nixonshead's picture, obscured by the perspective; certainly the semicircular cross section of the main fuselage seems apparent despite that; the angle may be fooling me into seeing the wing as relatively broader than it really is. On closer look pipcard's picture does show the nose region of the fuselage is pinched down toward a nose centered distinctly below the main hull centerline; STS then differs there mainly in needing to raise the windows above that slope to give the pilots some sort of forward view.
So OTL JAXA has not followed the STS template slavishly (certainly less so than the Kremlin ordered Buran to be, an exact copy of the Orbiter's detailed form by decree and purpose).
Still I wonder, in a TL where NASA was not almost completely preoccupied with optimizing such a spaceplane for the whole decade of the 1970s and therefore produced a form that certainly did have a whole lot of detailed research finalizing it, what are the odds the Japanese with nothing more to go on but their own clean-sheet work plus perhaps reflections on various abandoned European projects and old American military and NASA research from the early 60s would converge so closely to the STS look? Again does that merely indicate whatever else they may have failed to do, NASA did a good job in shaping the Orbiter OTL, and anyone else starting with a clean sheet and wanting to fit the same mission will come up with this same solution?
Now I'm looking at the image in Pipcard's signature link; from the perspective shown there the OTL HOPE differs from the STS Orbiter in other ways than number of vertical stabilizers. Its wing is relatively elongated and unlike the Orbiter its strakes enclose relatively more of the body, almost to the very front; the nose assembly seems somewhat different, more like a rocket nose cone and less like the airplane-like nose of the Orbiter; the body seems more cylindrical and less boxy.
All of these divergences from STS design might be present in nixonshead's picture, obscured by the perspective; certainly the semicircular cross section of the main fuselage seems apparent despite that; the angle may be fooling me into seeing the wing as relatively broader than it really is. On closer look pipcard's picture does show the nose region of the fuselage is pinched down toward a nose centered distinctly below the main hull centerline; STS then differs there mainly in needing to raise the windows above that slope to give the pilots some sort of forward view.
So OTL JAXA has not followed the STS template slavishly (certainly less so than the Kremlin ordered Buran to be, an exact copy of the Orbiter's detailed form by decree and purpose).
Still I wonder, in a TL where NASA was not almost completely preoccupied with optimizing such a spaceplane for the whole decade of the 1970s and therefore produced a form that certainly did have a whole lot of detailed research finalizing it, what are the odds the Japanese with nothing more to go on but their own clean-sheet work plus perhaps reflections on various abandoned European projects and old American military and NASA research from the early 60s would converge so closely to the STS look? Again does that merely indicate whatever else they may have failed to do, NASA did a good job in shaping the Orbiter OTL, and anyone else starting with a clean sheet and wanting to fit the same mission will come up with this same solution?
I think that thinking in "did they copy STS?" terms is a wrong way to go. I'd instead focus on the requirements for the vehicles.
Following a Marxist engineering philosophy, we might say that similar requirements drive to similar shapes. Among all the STS' ones, I'd say that the most significant is the Air Force's get-back-home-after-a-single-polar-orbit, since to fulfill it the Orbiter needed a ridiculous crossrange capability that wasn't considered in initial designs (Max Faget's STS idea was of an Orbiter with short stubby wings, more of a lifting body than a proper plane). It's not necessary for other designs to have the same delta wing layout, for example the Kliper was a simple lifting body, with little winglets and little more.
The ITTL HOPE might be delta winged because of its primary function: the JAXA wants it to be a significant adding to the world's space vehicles fleet, and what TTL lacks is a significant downmass capability. So (and this is some of a wild guess on my side) they designed it that way to maximize that capability, over what the Minotaur offers. Now, maybe they have some military purpose in mind that needs crossrange, but I frankly doubt it. The other reason you'll need crossrange is if you want it to land at Tanegashima, and you want to avoid the vehicle to drop in the drink if your reentry is somehow messed up.
Also, I think that even ITTL delta wings are pretty much well studied. They have been a mainstay in fighter design for years, and let's not forget that we have the notable Mach 3+ example of the SR-71, which dates back to 1964, and by this time is pretty well publicly known. So, I think they don't lack study material.
Following a Marxist engineering philosophy, we might say that similar requirements drive to similar shapes. Among all the STS' ones, I'd say that the most significant is the Air Force's get-back-home-after-a-single-polar-orbit, since to fulfill it the Orbiter needed a ridiculous crossrange capability that wasn't considered in initial designs (Max Faget's STS idea was of an Orbiter with short stubby wings, more of a lifting body than a proper plane). It's not necessary for other designs to have the same delta wing layout, for example the Kliper was a simple lifting body, with little winglets and little more.
The ITTL HOPE might be delta winged because of its primary function: the JAXA wants it to be a significant adding to the world's space vehicles fleet, and what TTL lacks is a significant downmass capability. So (and this is some of a wild guess on my side) they designed it that way to maximize that capability, over what the Minotaur offers. Now, maybe they have some military purpose in mind that needs crossrange, but I frankly doubt it. The other reason you'll need crossrange is if you want it to land at Tanegashima, and you want to avoid the vehicle to drop in the drink if your reentry is somehow messed up.
Also, I think that even ITTL delta wings are pretty much well studied. They have been a mainstay in fighter design for years, and let's not forget that we have the notable Mach 3+ example of the SR-71, which dates back to 1964, and by this time is pretty well publicly known. So, I think they don't lack study material.
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OTL HOPE-X wasn't going to land at Tanegashima.
It was going to land at Kiritimati (Christmas Island*) in Kiribati.
Why? "The candidates in Japan - including Magejima Island in Kagoshima Prefecture as well as Tono and Kamaishi in Iwate Prefecture, were ruled out due to overcrowded airspace and the necessity for space shuttles to fly over China and the Korean Peninsula to land"
*recently I realized that there are in fact two Christmas Islands. One is west of Australia while Kiritimati is in the middle of the Pacific Ocean south of Hawaii.
It was going to land at Kiritimati (Christmas Island*) in Kiribati.
Why? "The candidates in Japan - including Magejima Island in Kagoshima Prefecture as well as Tono and Kamaishi in Iwate Prefecture, were ruled out due to overcrowded airspace and the necessity for space shuttles to fly over China and the Korean Peninsula to land"
*recently I realized that there are in fact two Christmas Islands. One is west of Australia while Kiritimati is in the middle of the Pacific Ocean south of Hawaii.
I apologize for any wrong impressions I might have given. Normally I'd be among the first to defend the Soviets from the charge of "copying" American or other Western designs. Usually it is as you say; vehicles made for similar purposes will often make similar design choices, but a close look shows that actually the Soviet/Russian design is no copy at all.
Usually. Sometimes though the Russians have been known to copy, and this is on orders from the Kremlin. There was the case of their reverse-engineering American B-29 bombers as exactly as they could, for instance.
As it happens Buran was another such instance. Due to what I regard as some combination of wishful thinking and/or trash talk by US Air Force people about some of the things they hoped to use the STS Orbiter to accomplish, the Kremlin became very alarmed that the Americans were going to use it as some kind of superweapon--basically, if it could have been so used I suppose it would have been (not as a weapon of destruction but one capable of feats of hypersonic aerodynamic maneuvering in aid of intelligence gathering--and posing plausible threats the Kremlin was not sure they had appropriate means to counter). So the American talk was not, I suppose, realistic at all. Soviet engineering could hardly disclose the secret of capabilities that don't actually exist!
But it wasn't enough to settle their minds with their engineers' assurances that the US Air Force guys were talking nonsense and moonshine; the top Soviet brass feared we knew something they didn't. They therefore ordered that all alternate Soviet efforts at developing their own approach to reusable spacecraft and/or hypersonic orbital speed aerodynamic maneuvering craft be dropped so their resources, along with others, could be channeled into a crash program to replicate the Orbiter's aerodynamics. The Soviet engineers were indeed in this case ordered to copy the American design very closely, to cover the bet that maybe it could do things they didn't expect, and to have something on hand to exactly match American capabilities.Now they obviously did not copy every detail; some of the alternative choices they made, which include locating the launch engines elsewhere (on the Energia booster), replacing them with turbojet engines to make it more than a glider, and installing a built-in full autopilot capability so that a Buran could be launched and flown unmanned (and indeed the only flight was unmanned, and omitted the cruise/landing jets too IIRC) strike me as improvements on the STS design. But they were mandated to replicate its aerodynamics quite exactly and they did so.
Obviously my offhand, and shorthand, reference to the identity of Buran with the Orbiter has no bearing in the ATL here; in the ETS world, the HOPE-C design is the first craft to have this appearance ever. OTL there is nothing wrong with sticking with a tried and true design if it fits the envelope of operations you are planning. But I was wondering if the apparent similarity of HOPE-C to the Orbiter is an homage by the authors to what NASA's designers of the 1970s of OTL did get right. For the Japanese to independently come up with the same form, in a different technical era using different materials for a different mission would be quite a tribute to NASA's OTL vision.
However--my next post reflected on the probability that the impression of near-exact likeness I got from nixonhead's picture was in fact an error, a trick of perspective. pipcard's picture, if it does correspond to TTL's version of HOPE-C, shows some distinguishing differences.
The most important to this discussion may be the matter of proportions, the very thing nixonshead's picture, with its nearly tail-on perspective, may have obscured. While the compound double delta layout of the wings still looks STS-like to me, the ratio of length to wingspan is greater on the Japanese craft. This might address your own questions as to what the Japanese want in cross-range; if the delta is elongated I suspect that means they may have traded off some of Orbiter's OTL extreme cross-range for something else--lower low-supersonic speed drag for instance?
Well, that's pretty much my point. Why does HOPE-C resemble the Orbiter (if a distorted version of one) since the mission profile the Japanese plan for is so much different than the one Orbiter was designed for OTL? I'm aware of the many approaches to a spaceplane of some kind, and wish there were more OTL experimentation to hit on the best one for these kinds of peaceful missions. I was asking the authors to explain the paradox, and putting forth the suggestion that despite Orbiter's bastard ancestry OTL, perhaps the designers hit on a really good solution for a broad range of purposes--if so, it makes sense TTL designers would eventually hit on a version of it.
If not, the coincidence is striking.
OTL, if we come up with designs based on modified Orbiter planforms, we aren't necessarily being lazy or blinded by a fashion; we have lots of hard data on exactly what happens to that shape during launches and reentries; without that lore to influence the choice toward some transformation of the known planform I would have guessed the authors would have gone with some different shape.
Indeed, I greatly delayed this post looking up the various test vehicles the HOPE program of OTL used--and they are all over the map!
Look at the shape of HYFLEX for instance! I'd describe it as a "flying bathtub" or in a grim mood--as a coffin. It's nothing at all like the STS. To be sure, it is a test article, designed to parachute and splash down--and it was lost OTL, sinking after landing.
But here's the Google images page my search brought up--I find a lot of alternative approaches to the final vehicle suggested just in the first dozen or so.
Indeed, when I asked the authors the biggest downside to the way astronautics has developed ITTL, they said it was lack of downmass capability, and I spent a long time after that trying to come up with a solution to that problem based on a capsule design. I gave up, and it seems that the authors have concluded that downmass is what spaceplanes are good for.
This seems plain enough.
Japan of course is not supposed to have any military purposes in mind, period!
So I doubt it too.I don't think you need such a close resemblance to OTL Orbiter merely to have the downmass capability as such; Faget's straight-wing concept or any of dozens of other variations all offer that.
If Tanegashima is the launch site, I'd think there would be little need for crossrange just to return to it; eventually the orbit should be projected to pass right over it, so crossrange would only be relevant if they were forced to seek a landing earlier than the orbit crosses the launch site.
Or as I think you also suggest, should some sort of launch abort be necessary, the Japanese are launching over the Pacific, which is great as long as nothing goes wrong. But if something does--OTL shuttles only launched over the Atlantic, so landing bases on Eastern hemisphere landmasses cover a fair fraction of the possible suborbital velocities achieved. But by the time one has enough velocity to reach the west coasts of the Americas, orbital velocity is nearly achieved anyway. Therefore the only abort alternative to a splashdown is a very small number of very scattered islands; it is to reach those islands that are likely to be pretty far off any chosen primary course that one would want a lot of crossrange.
But frankly--how many of those islands can have airstrips on them the HOPE can use for an emergency landing? To be sure, HOPE is a lot smaller than STS Orbiter, meant to be in the 15-20 ton range at full scale--about the same mass as an Apollo mission in fact--so it can probably use shorter, rougher landing strips than the Orbiter could--but that's a relative thing; absolutely it is still a pretty stringent requirement.
Realistically, launching from the Japanese coast, one had best plan on the vehicle being able to survive ditching in the water, and rely on the friendship of the United States to have ships from its Navy on hand to fish it out, should something go wrong. in that case though cross-range requirements go right out the window; for that matter so might landing on airstrips. One designs the vehicle to splash down routinely--and we are back toward capsules again. The Hyflex shape, the "flying coffin," is looking pretty good now! (Of course splashdown is exactly what it didn't survive OTL
)Again--this is my point. STS does not have a bog-standard delta wing; it has a double delta. If designers had freedom unconstrained by the example and data base associated with the OTL STS program, what are the odds they'd pick something so similar?
One thing I think the timeline overlooked unreasonably is the Soviet Spiral program. The Russians were developing, in the 1970s OTL, a small, fighter-plane sized, spaceplane based on a lifting body planform. Data from its flight tests, observed by American spy sats, influenced a choice by NASA-Langley to develop the HL-20 design, which was proposed as the backup design for space station operations in the late 1980s; this led eventually to Dream Chaser.
The thing is, I don't think the Soviets OTL were pursuing Spiral and other variations on the reusable/hypersonic maneuverable spectrum in response to the US choice to concentrate on STS. They were doing it because it was an interesting problem with promising solutions in its own right. Therefore it was not reasonable for the authors to butterfly Spiral away, and what did terminate Spiral OTL was as I said above "Shuttle panic" on the part of the Kremlin. Had the USA not developed STS in the 1970s, I think the Soviets would have gone ahead and developed Spiral rather more. The upshot of that would be that the Soviets would have something quite comparable to HOPE, but two decades earlier.
I submit that since downmass does emerge as a deficiency of capsule-based programs, that a Soviet-based spaceplane alternative would have been more attractive on the international market than TKS. I wouldn't suggest that TKS would have been eclipsed, but having something like Spiral handy would have been an asset to the Soviet program and inspired rivals to develop their own spaceplane approaches.
And my guess is, none of them would look remotely like a Shuttle, except for the broad similarity that delta planforms would tend to prevail.