Chris Hadfield posted a little Soyuz tidbit to his Facebook page the other day. Part of the preflight prep for a Soyuz flight is taking 2 enemas… apparently you really don’t want to have to poop in the Soyuz toilet.
Just a little bit about the Space Shuttle computers:
The original memory medium was iron core (as was the Apollo spacecraft–can’t speak for Gemini or Mercury–I dunno). Supremely robust with respect to radiation resistance. You don’t don’t a want bits flipping in memory during critical flight operations. And should the iron core flip a bit, it doesn’t really matter anymore–the computer will never be able to read it; it died long ago along with the astronauts from Godzilla-level amounts of radiation.
The Space Shuttle eventually upgraded to rad hard semiconductor memories, but required additional hardware in the form of a an Error Detection and Correction (EDAC) device for use on the RAM. This was used to sniff out single-bit and double-bit errors and correct them on-the-fly (in some cases even triple-bit errors could be corrected). If the EDAC’s correcting abilities couldn’t handle the errors, it signaled the flight computer(s)(?); which, in turn, execute a handling routine to deal with said error(s).
The implementation, IIRC, was to have the EDAC iterate through the RAM memory continually (of course, the EDAC would perform a check/correction before loading the instruction/data into the processor). Otherwise, if you only used the EDAC during the instruction/data fetch phase, you had the possibility of accumulating so many bit errors, you wind up swamping the processor with error handling calls. Not a particularly good thing to happen on the re-entry phase.
It’s what the Soyuz does, but the Orion is designed for much longer trips - to the Moon and beyond. So was the Apollo.
Also, the current Soyuz isn’t actually a 60s design. It was originally designed in the 60s but its design has been upgraded over time. The current model, Soyuz TMA-M, first flew in 2010.
The Soyuz is just the capsule though. The more remarkable part is the R-7 rocket used to launch the Soyuz. Its design directly traces back to the R-7 Semyorka, the very first ICBM in the world. A variant of this missile was was used to launch the Sputnik.
I didn’t even know if the Soyuz had an actual ZG head until the later generations (Apollo didn’t – first were in Skylab and Salyut). It has always been a minimalist spacecraft – the reentry module interior is just enough volume for three uncomfortably packed people and an instrument panel, and anything else went in the expendable orbital module. So it’s probably very spartan. As I understand it, the latest versions of the Soyuz TMA have been optimized for the Earth-Station-Earth ferry/lifeboat mission rather than sustained independent flight operations (which is a capability the US seems to prefer for their next-gen vehicle).
It seems to me that NASA is being pushed towards manned exploration. Those missions will require LV which is too large to have any commercial purpose. No private company would develop one without a cast iron cost-plus NASA contract. In which case, it may just be cheaper to do it in-house and out-source smaller parts only. STS may have gone over budget, but it was no worse than many “commercial” military projects.
There is nothing left to reactivate.
The Soyuz IS a 1960s design it actually is the old VOSTOK-with a third cosmonaut. Any changes have been largely upgrades to the same basic design. Now, the ISS is nearing the end of its design life-what is next? maybe the Chinese are into a big prestige product-are they?
Yup, pretty ambitious: Chinese space program - Wikipedia
The second part of that statement is wrong. You’re thinking of the VosKHod (and Vostoks were one-seaters anyway). Those were first-generation LEO-only up-and-down ballistic-reentry vehicles with no orbital flight autonomy beyond manual retros in an emergency. The Soyuz OTOH was designed as a second-generation orbital-maneuverable system with rendezvous-and-docking and (limited) aerodynamic-reentry capabilities and, yes, upgradable.
It is true Soyuzes are mid-1960s designs – but isn’t a 737-NextGen series at heart a mid-1960s design, then? The Russians have been trying to come up with a true “clean sheet” next-generation manned vehicle for a while but it has been as tricky for them as it has been for us and just like us they’ve blown piles of rubles on several concepts that never get beyond the drafting board/CAD screen before the funds run out.
Hey, it IS rocket science.
How is that different from what I said?
Especially in the context of your post that I was responding to. It’s one thing to continue upgrading the same design, keeping the production facilities alive, making sure the part are available (or modifying the design to use available parts). It’s significantly harder to build to 50-year old blueprints that haven’t been updated.
R-7/Soyuz has the advantage that they’ve worked out most of the ways it can kill its crew. 
I wonder what their success rate has been compared to the shuttle.
Looks like two fatal incidents for the Soyuz, total of four fataltiies. Soyuz had 26 umanned flights, plus 66 manned Soviet missions and 52 Russian missions, for a total of 144 missions.
The space shuttles flew 135 missions, with two failures and a total of fourteen fatalities.
So they’re comparable in terms of mission failure rate, but a shuttle loss is more tragic because there are more astronauts aboard when it happens.
It’s worth noting that the two Soyuz accidents happened decades ago; the second one was in 1971. They’ve been fatality-free for over forty years now, whereas the two shuttle incidents happened much more recently; it appears Lumpy is right.
As you point out, a considerable amount of the effort in the error checking. Spacebourne avionics are far more subject to what are termed “single event interrupts” (a failure of a single logic path), primarily due to ionizing solar and cosmic radiation which is shielded on the ground, and because of the criticality of function there has to be code that checks the code, and code that checks the code checking code, and so forth, such that there are actually several layers of error checking which have to be essentially foolproof during all phases of operation (not just reentry, although that is certainly a crucial period for any non-ballistic reentry profile). And unlike something like a website CMS, this cannot be abstracted from the hardware to any significant degree; embedded code is basically running on “bare metal” and the code is very specific to the computing architecture and details of the hardware function, so that even a minor change to the processing hardware requires almost complete revalidation of the flight code up to the system level.
You are correct that NASA is being given the mandate to maintain some kind of crewed program–whether it makes sense in terms of scientific and exploratory research or not–but even given that, the SLS is suboptimal. For one, it makes the same mistake as the STS in trying to combine heavy lift and crewed capability, which combines high performance (in terms of absolutely payload) with a high degree of redundancy, which are often competing objectives. A better configuration would be a lower propulsive performance heavy lift vehicle with a somewhat reduced expected reliability with a compact crew-only launch and return vehicle intended for deliverying crew to a space station or transfer space craft. The cost/benefit of this is clearly demonstrable, but it would require the development of two parallel systems which NASA cannot afford, and the safety culture of NASA will not accepted reduced reliability even in a cargo-only vehicle despite that it could potentially reduce both development and launch costs by an order of magnitude.
I will point out that SpaceX is, in fact, developing a heavy launch vehicle (the Falcon Heavy, using three Falcon 9v1.1 core first stages) which they at least claim will meet human-rating standards. Whether this is true and it will demonstrate suitable reliability is still in question, as is the market for human spaceflight at this point given that there is really nowhere to go to and that space tourism is an industry with a definite limit at any reasonable price point. Blue Origin is also claimed to be developing a partially reusable crewed orbital launch system, albeit more quietly than SpaceX. So, whether it is ultimately financially viable or not, there are organizations making the effort to develop crew-capable launch vehicles and systems, and from a cost standpoint it likely makes more sense for NASA to contract those capabilities as services with in-house mission assurance rather than the expensive internal oversight from multiple groups that they levy on their own programs.
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It should also be pointed out that the capability of the STS/Shuttle to recover from any catastrophic flight failure was extremely limited; basically, it could survive an engine out failure by either Abort-To-Orbit (one occurrance) or Abort-To-Launch-Site/Abort-To-Alternate-Site (never) during ascent a small part of the ascent phase, and could only abort on reentry during the last couple of minutes of subsonic flight. During the initial liftoff phase, the only survivable abort profile was after it was well-clear of the tower and before transonic regime; and there is no abort mode for any propulsive failure of the SRBs. (Technically Challenger wasn’t propulsive failure of the SRBs, but structural failure of the External Tank which resulted in aerodynamic shear that caused the system to tear itself apart, which caused failure even before combustion of the LOX and LH2 leaking out of the tank.) In contrast, Soyuz (and Apollo, and the SLS) should be able to abort during the entire ascent phase from liftoff to Stage 1 MECO up to catastrophic loss of engine/booster, and could likely survive partial failure on Stage 2 (loss of performance/loss of engine) all the way to orbit.
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BTW Soyuz has survived two ascent phase abort to Earth incidents – 1975’d Soyuz 18a a staging malfunction at S3 separation, and 1983’s Soyuz T10/1 booster failure on the pad which required firing the escape tower rocket,
Thanks for crunching the numbers. Interesting comparison.
NASA expects to be contracting commercial crew launch providers in the near future, sooner than SLS will be completed. SLS is not really intended to serve as an ISS crew provider, but rather to serve as the launch platform for more distance exploration.
Why didn’t the ESA complete their own mini-shuttle craft 9the “Hermes”)-that would have cost less than the shuttle, while having some of its advantages (reusable, pilot landed).?
Sure, but even on that basis the SLS isn’t very competitive. Even if the Falcon Heavy ends up costing three times as much as the advertised cost per launch, it would still be cheaper to launch two F-H launchers as one SLS, and given the advertised production rates per core and launch rates, the availability of the F-H or a similar vehicle will likely be far greater than an SLS. Whether SpaceX proves out the system to come close to the advertised performance and cost is another question, but nonetheless they are at least aiming for launch rates that make the support of some kind of space infrastructure viable versus the one to two flights per annum that the SLS can support, and given the commonality with the Falcon 9v1.1 (which hopefully has some genuine commercial demand) it can provide enough continuing production to achieve a suitable economy of scale.
Fundamentally, the SLS fills the niche left by the Saturn V. The thing that astute observers will note is that without a continuing series of lunar or libration point missions, there just wasn’t a lot of demand for the Saturn V, and the system was inadequate to support transplanetary exploration. Despite Congressional pressure, there is really little scientific or commercial need for a regular crewed lunar exploration program, and the need for a crewed libration or asteroid recovery program beyond the single proposed mission is unclear. Indeed, the need for crewed transport beyond the planned service lifetime of the ISS is unclear, at least as far as NASA perogatives are concerned.
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NASA’s path forward is murky. The eventual goal has been stated and approved - we’re going to Mars… eventually. The problem is no one has a clear idea of what that means, when and how to do it.
Sure, we will need a launch vehicle, and a heavy launcher allows quicker/easier assembly of whatever vehicle we devise. Sure, we will want to do some sort of near-space exploration prior to that trip to verify the vehicle and whatnot.
We can’t get commitment to return to the Moon. We can’t get commitment to go to a near earth asteroid. The current plan seems to be to bag an asteroid and drag it to lunar orbit, and go visit that. I don’t wish to derail this thread discussing the merits of that plan. Suffice it to say that scientifically that isn’t particularly valuable, and as far as long term space development goals, it isn’t very helpful. But it does allow us to device some nifty robotic mission, do something ridiculously challenging, and pretend to accomplish something meaningful.
Honestly, a heavy-lift launcher is probably not the best direction for NASA to be going. Commercial space has promise to provide what is needed in that realm before we have anything that needs to use it.
I’m really torn on all this, because my job is in the mix and I’d sure like to keep something for me to do. But with the budget the way it is and politics as nasty as it is, the muddled non-plan we have is the foreseeable future.