DoctorEvo

This has been one of my favorite sites on the internet for years. Oh, boy, do NOT get me started on those arrogant windbags. >

Because someone thought it\'d be a good idea to model engine overheating. :

That flywheel would load up with angular momentum like a city tram in downtown Tokyo. I mean, it might be possible to unscrew a single bolt before it got COMPLETELY loaded up, but the power consumption would be insane, and after you get the bolt out, your flywheel would still be spinning until you found somewhere to dump all that momentum (perhaps... by screwing that same bolt back in again?). Yeah, not practical. It\'s way easier to just anchor the tool (or more likely, yourself) to whatever module you\'re working on and transfer all that angular impulse directly back into the hull. Yet another reason why trying to work on something without directly or indirectly grappling to it is purely sci-fi level engineering. Probably not even. I mean, for the inside door, it\'d probably just flop open once pressure equalizes unless you had it latched closed. I\'d say that\'s pretty clearly indicative right there. The outside would be only slightly less pronounced, but you\'re still gonna know if there\'s any pressure still pushing on it if you use any sort of pressure-tightened latch (camlock, pressure-actuated locking pins, or a tapered detent). I think you suggested that. Anyways, the airlock is already going to need a circuit/valve bleeding air in to pressurize it, and I can\'t see it being that difficult to just add a filter to this and keep it running whenever the box was open. Of course, most modern spacesuits have their own filtration systems (usually integrated into the scrubber circuit), and approach clean-room conditions anyways, so I didn\'t really think it\'d be an issue.

And by my reckoning, would\'ve probably cost about half as much per launch as the Shuttle wound up costing, albeit with almost no parallel payload capacity. Sounds like Big-G would\'ve made a better schoolbus, but a worse pickup truck. Heh. Sounds like maybe another artifact of the direct-ascent lineage. Zero torque on the wrist? No, I don\'t think so... Sheesh, that\'d be hard to do. The best method I can think of right now is something that just friggin\' tack-welds itself to the spacecraft hull once you get it positioned, and that seems a little . . . yeah. Otherwise you\'d pretty much need either special fittings on EVERY SINGLE FASTENING PONT to index into, or give the tool its own dedicated RCS system (which is . . . yeah). We\'re talking like 5 PSI here. I think general handling and abuse is going to be a much bigger issue than the air pressure on our box\'s structure. Yeah, I considered that. It is tidy and quick... but I feel like it\'s a no-exceptions two-handed job. A rock-in-and-latch deal could probably be manipulated with one hand. I dunno, tough decision. Too complicated. I\'m thinking just a simple, short (~1/2') plug seal (I picked a plug seal over say, a flat gasket seal to place more resistance load on the camlocks/detent when under pressure relative to when unpressurized), probably with the male end on the airlock. I was thinking I\'d use airlock pressure rather than elastic pressure to engage any detent/camlock/locking pins, so that there\'d be (at the very least) a pronounced resistance to opening it while pressurized, which\'d be practically nonexistent while unpressurized. With as much plug-seal play and area and pressure as I was planning on, my camlock(s) could probably be configured such that their pressurized resistance was greater than could possibly be opened without depressurization. Of course, a dedicated pressure-switch-actuated locking pin would be even safer, but it\'d be more complicated as well (i.e. another thing to break, possibly leaving you with an awkward bulge stuck on your frontside). In any case, having such tangible feedback built in (i.e. letting the user 'feel' the pressure state of the airlock) would eliminate the need for any special instrumentation to monitor airlock operation. Well, I wouldn\'t want the airlock hardware to consume any significant space when not in use, so I think a permanent 'HAZMAT-safe' barrier with some hokey little gloves poking through it would be out of the question. Maybe if there are concerns of possible HAZMAT contamination, you could put the part (and any tools and other associated bits) into a special transparent HAZMAT bag that you could work through before putting it in the airlock. Or you could just, y\'know, not bring it inside...

So basically exactly what Max did?

Ah, here we are... It looks like the initial test articles for MX-774 used the simple gyroscopic guidance system similar to the V-2\'s, but Convair set out to develop the very same Azusa radar-tracking command guidance system that was eventually used on Atlas-D. So yes, it looks like they probably could\'ve had an intercontinental missile with a CEP on the order of five miles by 1950 - but still no warhead small enough to launch with it. Ah, here it is: http://www.thespacereview.com/article/1326/1 Looks like this one\'s where it finally bursts... Apparently there was a video, but it got pulled. In any case, the pictures tell the story pretty clearly. Yes, by Von Braun\'s standards, Bossart was clinically insane in more ways than one. He was, after all, one of the first proponents of LH2 propellants as well... Inertial/command. A interferometric radar ground station would track the rocket during launch and send updates to the rocket to make corrections. The military pushed for an independent fully-inertial system which was implemented in Atlas E and onwards, but the technology developed for the Azusa system saw continued usage in the spaceflight industry, with related ground-based tracking and command systems being the favored system right up to the Shuttle era, and even today to some extent (complimented by GPS and TDRS). They used an RD-180, not a 170. And performance is performance; adding extra weight that doesn\'t otherwise help performance is a performance penalty no matter what engine you have underneath. As for the logistics, I think transportation and assembly are by far the more difficult aspect of handling balloon tanks than fueling is. For fueling, the fuel hoses are pressurized by pumps anyways, and I\'m sure pressure CAN be reduced on an Atlas even during on-pad fueling (maybe not down to the 5 PSI that they were stored at, but somewhere significantly less than the 25-30 PSI they launched with) if need be. Atlas already had all the systems for regulating pressure internally after fueling, so I can\'t see all that much extra external infrastructure being required to maintain pressure during fueling, aside from a pressure fitting on the nozzle-end of the fueling hoses. During transportation or assembly, on the other hand, the rocket\'s own pressure regulation systems are disabled and the rocket must be kept pressurized to 5+ PSI with nitrogen at all times. Now it\'s not terribly difficult to keep a steel balloon from leaking, but care must be taken not to open the wrong valve at the wrong time, and the pressure should probably be monitored during transportation. Oddly enough, the Falcon 1\'s second stage is not considered pressure-supported at all. Of course, being a pressure-fed stage rated for more than 135 PSI, the fuel tank itself is built heavily enough to completely eliminate any need for dedicated structural members at all anyways - pressurized or not. I sometimes wonder if this may be the answer - to simply increase the pressure rating of your fuel tanks so they can handle all assembly and pad loads unpressurized, and then re-assess your engine choice to see if the weight of the turbomachinery is really worth the ISP increase. (I mean, heck, the Kestrel, with a mere 135 PSI chamber pressure, achieves a vacuum ISP even better than Merlin does with its turbopump and 1000 PSI combustion pressure, just due to turbopump and nozzle losses!)

It depends on your standards. A continent is a pretty big target. Obviously, V-2-level inertial guidance was available. With the thermonuclear warheads that WERE eventually developed, they could've caused plenty of devastation even with a poorly-guided missile. I know the incident you're talking about. And I don't believe there is any motion footage of it, but the photo sequences I've seen do the job just fine. They were defuelling, and someone forgot to open a pressure valve. There was no leak. The balloon tanks were actually incredibly durable when pressurized - Bossart invited ABMA (including the very-skeptical Von Braun, who was known to had said of Mercury-Atlas astronauts that they deserve a medal just for having the bravery to SIT on top of one of Bossart's 'flimsy' rockets) to come and hit one of his fuel tanks with a sledgehammer. ABMA obliged, and the sledgehammer simply bounced back with such violence that it nearly maimed the technician who had taken the swing. The tank was completely unharmed. Ahahah. No. Titan I was semi-cryogenic. In fact, the LR-87 developed for the Titan is one of the few engines capable of burning RP-1, hypergolic, or liquid hydrogen propellants interchangeably with just a few modifications. Atlas D and E both only took about fifteen minutes to elevate, fuel and fire from an alert state. Four hours may be the response time when not on-alert, though I have no idea what would take four hours to do. Then again, they say that the R-7 could take as much as twenty hours to prepare to launch... Yeah. I never understood why they gave up on it with Atlas III - the performance is simply astounding. The original Atlas was in fact capable of performing true SSTO with a reduced payload. SpaceX seems to think it's a good idea, as the Falcon I uses a partially pressure-supported structure. And of course, Centaur sees continued usage as one of the best high-energy upper stages out there, and ACES will carry on the balloon-tank structure into the next generation of high-energy transfer stages.

Well... But given they managed to get 20 or so flights on average out of SRB segments on average, I think there are some significant savings to be had in that area. Maybe. Ares I and Orion both are far larger and heavier than Soyuz, being more closely-comparable to a Saturn I/Apollo in terms of scale. Thus it is probable that Ares I launches would remain somewhat more expensive than Soyuz launches, though probably with a much lower cost-per-kg on cargo missions, should it ever be used as such. Well development costs for reusable parts are slightly higher, purchase costs are substantially higher, but you get to use them for what would normally consume several expendable counterparts. For instance, let's say a Shuttle SRB costs about three times that of an equivalent expendable booster, but you get to reuse it about 20 times. Worth it, right? Unfortunately, it isn't THAT simple, as the costs of recovery and refurbishment and reloading are actually quite significant, but the potential for massive cost savings is there. Two years? Seems pretty tight for NASA... But yeah, as far as the contractors go, they could easily have everything ready to go by then. How did that happen? Did Orion turn out heavier than they initially planned? Anyways, I can't see it being a terribly difficult thing to fix, since the second stage is all-new anyways and could probably be stretched to make up for it. (After all, it WAS stretched and contracted several times early on in the design process...) Funny you should mention that... ATK isn't one to pass up such an opportunity: http://en.wikipedia.org/wiki/Liberty_(rocket) Unfortunately, they didn't win a CCDev contract, and are a little pressed for funding now... Yep, I mentioned that. Well I, for one, am in FULL support of the development of an inter-maria high-speed-rail network on the Moon. Nah, but really, I do feel that as the industry matures, costs will come down and the market will grow. It will be slow, but it will happen.

Well, we eventually got the Shuttle, for what it's worth... ;D My Google-fu initially suggests 5 degrees. Oh yeah, I forgot the coolest part - an LCD screen with selectable torque and RPM settings. Well, if the airlock is modular, then you might not even NEED a dedicated outer door - perhaps just swing open the entire box to load/unload it. Latch it in place w/ object inside, pressurize it, knock on it some to make sure it's secure, and then open the inner door to grab the object. A safeguard for the outer door/unlatching the airlock makes sense... maybe some simple camlocks would suffice - designed such that their closed resistance becomes significantly greater if they are under pressure.

Right NOW? Well I think the BIGGEST reason is because they've already put in so much into Ares and they don't want all that development to go to waste, and because a single-launch mission is much easier to coordinate. It is fairly unlikely the SLS will be very cost-effective unless they make some major changes to it. However, I'm frankly kind of disappointed they didn't put their big dreams on hold for a while and go forward with the relatively modest Ares I, though. Even if it's just a small space taxi, it'd be enough to lift much of our dependence on the Russians for the ISS program, and it actually has the potential to be very cost effective.

That, and Convair was much better-versed with rocketry than their competitors were, having designed a true ICBM as early as 1946, but not having built it since warheads were not yet small enough to be launched by one. It's still immensely easier to handle than something that needs to be assembled and transported vertically. The same was true of Titan I. Atlas F was, for all intents and purposes, equivalent to Titan I in terms of response and survivability. Earlier, horizontally-stored Atlases were only marginally slower, but their coffins had lower survivability and fuelling had to be done outside of the coffin with no protection whatsoever. Atlas F could be kept on alert in-silo for prolonged periods with the kerosene tank full. From this point, it could be fuelled with LOX (in-silo to enhance survivability), elevated out and fired in the span of ten minutes. That's every bit as good as Titan I. Oddly enough, they concluded that attempting to divide Atlas, with its lightweight balloon tanks, into two separate stages without stretching would actually negatively effect performance due to the added dead weight - it was actually better to carry all that tankage with you than to bother figuring out how to leave some of it behind. In fact, they later went EVEN FURTHER with the stretched Atlas H. You gotta admit, those balloon tanks were LIGHT. When it comes down to it, the Titan's biggest advantage over Atlas was raw muscle - bigger, taller, heavier... Atlas really never stood a chance.

Atlas is very comparable to R-7 (the rocket that Soyuz is launched by) in many ways. The Mercury spacecraft was obviously quite a bit smaller and more primitive than Soyuz, but the rockets are similar in terms of performance, cost, growth, etc. Dude, have you NEVER heard of Progress or Fregat?

Yes, that was pretty much the idea. However, MTBF is usually not used to define replacement intervals, but rather inspection intervals, with parts being replaced as needed - that is, whenever they fail, or whenever they pass certain margins, depending on how critical they are. After Challenger, though, they refused to take ANY chances - even though the vast majority of their measures were completely unrelated to the cause of the disaster.

Well, bluntly put, yes, that can be the case. 100t+? There are all of TWO rockets with that kind of payload, and of them, Energia was the closest - and it was only ever launched twice, before political turmoil caused its cancellation. The N1 was close, and it WAS actually a fairly inexpensive rocket given its size. But if you choose a more reasonable and diverse criterion - say, 25 or 50 tons - you start to see some very successful rockets with excellent costs-per-kg. If you can use reasonable building practices and avoid building above your means, you CAN achieve fairly good economics by simply up-scaling. Well, we've been over the reasons Saturn was expensive before. Currently, the 'happy medium' you're talking about seems to lie in the neighborhood of 50 tons (with Proton and soon the Falcon Heavy leading the pack), but it WILL grow as the industry grows. Yes, well, there is the factor of how a one-piece spacecraft will probably weigh much less than a modular design assembled from 50 components, but I'm ignoring that for now because it's a little hard to estimate HOW much heavier modular designs would be. I do like the EOR/LOR scheme you proposed before, though - where the ultimate plan is to reuse already-launched hardware several times without recovery. That would most likely have a major impact on the average costs-per-mission, especially for low-mass-fraction components.

Yes, but I'm not talking about 'sustained turnaround rates.' I'm talking about maybe checking some of the more reliable or less-critical parts maybe, every third or fifth launch. Of course, certain parts will need to be swapped or inspected every flight, but many components can be trusted to survive multiple launches, especially if they aren't critical. And if you DO find parts that are wearing well past tolerance during the inspection intervals, you can shorten those respective inspection intervals, and lengthen intervals for components which are not wearing as fast as expected. If you stay rational about such issues instead of completely flipping out when something goes wrong (or, on the other hand, being complacent and ignoring problems outright), you can actually maintain a healthy balance between safety and utility. Why every flight? You don't trust an APU or a hydraulic pump to work for more than a single flight in a row? If you distrust your hardware THAT much, then you have no place in such a high-stakes endeavor in the first place. It's worth noting that many catastrophic mechanical failures in the aerospace industry are human error, caused by careless or hurried maintenance. Sometimes there are actual SAFETY-ORIENTED reasons for choosing the less-frequent, more-deliberate inspection and maintenance schedules, lest someone slip up and leave a rag in your turbopump after their hundredth time disassembling and inspecting it. I don't think so. Replacing stuff takes time. I'm pretty sure the 2-week turnaround consisted of just replacing the components that were actually broken, assembling the stack, rolling it out, and launching. Like I said, there was no illusion of being able to sustain such ludicrous launch rates. Extensive inspections WOULD be required at some point, resulting in a sustained launch rate MUCH lower than this shortest-possible turnaround time.

That'd be just fine, except the opposite is almost universally true - larger rockets achieve a much lower cost-per-kg to orbit. Well between launching a rocket that's 5 times larger once or launching five smaller rockets into the same orbit, the bigger rocket is almost always cheaper. The only reason to use multiple smaller rockets over one bigger one is if the payloads need to be placed into their own orbits.

DoD specified two weeks. The fastest they actually performed was eight weeks. The fastest achieved post-Challenger was thirteen weeks, and the idea of deferring any inspections for one turnaround was considered unacceptable - they just flipped and decided that all the sudden they had to check absolutely everything, absolutely every time. Note that turnaround time is not a sustained launch rate (well, at least not in the initial pre-Challenger case). The sustained launch rate was somewhat slower, initially limited by external tank production to 24 per year for the entire fleet. Of course, even with a four-orbiter fleet, the slow turnaround rate caused by the expanded post-Challenger safety measures easily drowned this limitation. IF they somehow sustained that thirteen-week turnaround for the entire four-orbiter fleet (not possible given that the Orbiter Processing Facility isn't capable of handling four orbiters at once), they'd still only manage 16 launches per year.

Heh, school, and I decided to go active again with Incredibots too... but yeah, I'm probably not going to be posting as frequently for a while. This discussion is too interesting to disengage from altogether, though. Sheesh... that's like, 7 meters I think? Yeah, no wonder they figured could squeeze more crew than the shuttle! Well, naturally. The RCS WAS rated to steer the whole stack, so there's no reason it shouldn't be able to steer it under thrust unless the CG is just WAAAY out. Heck, if it was in-trim enough that you only needed 50% of maximum RCS authority, you could get away with firing aft-RCS only and suffer virtually no propellant waste over a gimbaled burn. I ran the numbers earlier and I think I figured about half a degree of SPS gimbal equates to a 100% RCS-couple duty cycle. So yes, I guess gimbaling would present considerably more control authority than the 100-lb thrusters alone. Yeah, it would be the best way to purge everything. Even the fire retardants themselves have the potential to be irritant. That can wait, though. Well, from what I can find, it looks like the driver they use has a chuck for interchangeable heads, so I can only assume they actually use it. Apparently it uses NiMH batteries and has a special skinny handle and trigger for gloved usage, too. Naturally. Internal-opening, about 75-150 in2 in area... should be enough to keep it from being opened prematurely. And if the airlock comes unsecured during pressurization, at least the inside door will still be closed.

Well if you can't pull it together enough to start building the proper hardware, you can bet you aren't going to pull off an interplanetary exploration program. Boosters? I'm sold.

PROS Shuttle: Semi-reusable, fast-turnaround, EXTREMELY large crew capacity, heavy-lift capability, potential to be very cost-effective for frequent launches. Gentle reentry with wide crossrange capability. Saturn V: Super-heavy lift capacity, solid safety record. Minimal primary development costs. Soyuz: Proven R-7 rocket, simple and cheap horizontal assembly, well-evolved spacecraft with extremely low-weight construction, very low per-launch costs. Shenzou: Similar to Soyuz spacecraft in many respects. Low cost. N1: Heavy-lift capability. Horizontal assembly. CONS Shuttle: High initial development and production costs. Lack of comprehensive launch-abort modes; labor-intensive post-Challenger safety measures crippled the program in nearly every respect. Requires considerable (but mostly pre-existing from Apollo) infrastructure to launch. Difficult to fill its payload capacity given its restricted launch inclinations. Saturn V: Very high production costs for an expendable vehicle. Difficult vertical assembly required. Considerable new infrastructure (VAB, cryogenic fuel production) required. Difficult to make use of its superheavy payload capacity. Soyuz: Fairly low lift capacity. (Can be seen as a good thing in some ways, given the extremely-low per-launch costs). Shenzou: Long March rocket uses slow vertical-assembly and has a questionable safety record. Low payload. N1: Abysmal launch record. Complex design. Is this for manned rockets only?

I'd say that there's more than enough disparity here to say that this rocket is NOT a member of the Saturn family whatsoever. It's pretty solidly Shuttle-derived. The resemblance is purely aesthetic. You know that's just an adapter, right? The S-IVB itself was entirely cylindrical and 20 feet around at both ends. With a different adapter, an S-IVB would mate just fine to Orion without scaling. Besides, the EDS is shuttle-ET based anyways, so I think it's safe to assume it'll be considerably wider and more squat than S-IVB. Exactly. Well that's kinda fallacious... the same is true of pretty much all expendable engines as well. Viking is the only liquid engine I'm aware of that is regularly flown without being test-fired first. Otherwise, you're gonna have to turn to solid-fuelled engines if you wanna have that sort of launch flexibility. The cost issue is clearly by far the most significant. It does seem rather silly to use SSMEs in an expendable manner. Probably. Performance. RS-68s use a wasteful gas-generator cycle, similar to that of the Apollo-era J-2s. They also have a lower thrust:weight ratio than both the SSMEs and the J-2, which in my opinion is inexcusable for a simple gas-generator engine, especially considering how recently the RS-68 was designed. All this amounts to a sizable performance hit in terms of payload-to-orbit. Omitting the boosters would be out of the question. The fact that you could get away with using only three of them is peanuts when you consider that three of them would still weigh almost double that of five SSMEs. All said, though, it might be worth taking the performance hit just for the sake of cost savings. First stages are big and expensive, and looking for cheaper, heavier, less-efficient solutions (for instance, SRBs) is a very reasonable thing to do (unlike on upper stages, where the costs of excess weight trickles down to lower stages as well). Beauracracy. That's all I have to say. They're both Shuttle-derived, but there are a few significant differences. For one thing, unlike SLS, Ares V was not man-rated. It was expected to be used in tandem with the man-rated Ares I, a much smaller and very distinct (SRB-derived) rocket. Ares V was two stages (plus boosters) only, whereas SLS is planned to be single-stage plus boosters for most low-orbit missions, and two-stage only for higher or heavier missions. But yes, in the two-stage configuration, SLS is very similar to Ares V, and the whole thing is rife with politics. Huh? I don't think so. Constellation had a faint inkling of possible interplanetary missions in the distant future that *might* be possible but probably won't happen, while SLS doesn't seem to have any notion of leaving Earth orbit at all. The problem with that is that robotic space exploration can already do everything manned exploration can and more. If your goal is only science, then manned exploration is obsolete. Why? The LES doesn't care what's behind it. It'll pull you away from boosters or liquids or a silo of irradiated nitroglycerin all the same. SRBs are not the problem. A missing exit-strategy is the problem. Because Earth-Orbit Rendezvous is just a crutch for when you don't have a rocket big enough to do the job in one shot. Oh jeez. I don't think even the ISS has enough consumables for the whole trip there and back. Maybe with a single crewman. Anyways, I think there's one thing above all that needs to be said about this rocket: [shadow=red,left]IT NEEDS MORE BOOSTERS.[/shadow]

Hmm. Well in that case, a shorter SM would have LESS lateral forces on it, thus causing an INCREASE in aerodynamic stability... Of course, the reduced mass would shift the CG aft as well (destabilizing things), but this shouldn't be significant for either S-IC or S-II flight phases, and S-IVB flight is wholly exoatmospheric, and the LES has dropped by then anyways. There is the issue of moments of inertia, but I don't know what to make of that. Again, I think it'd be insignificant until S-IVB flight. A WHOLE S-IVB, or a tapered adapter like Apollo had? There's a reason Glushko had a hardon for hypergols... Hmm. I always figured gimbaled engines as a replacement for dedicated aft-facing vernier thrusters, not as a supplement. But I guess chuffing away with your RCS to keep your wonky-loaded CSM lined up isn't quite as efficient as gimbaling... (still, I wonder how much weight they could've saved from it... eh, I guess up-rating the thrusters for abort probably would largely defeat that purpose) But Soyuz's engine doesn't gimbal, I know that much. I don't see how that could help at all with solar observation... unless they were listening for radio noise and were trying to maximize their time over radio-quiet extreme Southern latitudes... Yes, but I wonder if the extra exertion from the extra pressure might defeat the purpose... Meh, probably not. Also, I worked it out, and alveolar ppO2 at sea level is 2.7 PSI delivered when waste-gas dilution is taken into account. Thus, the ACTUAL pure-oxygen pressure needed to match this would be 4.4 PSI absolute. Not necessarily. Some stuff burns just fine in a vacuum. And odds are, if displacing the oxygen away from it doesn't do it (ESPECIALLY in the presence of a fire suppressant), evacuating the chamber won't either. I thought they pretty much already carried a regular socket set... one hand drill, and a bunch of heads for it. I think a hand drill is more simple and modular than a fixed 'R2-D2' deal. I dunno, I'm still leaning towards the front. It just seems like it'd be too difficult trying to move tiny fiddly parts too far away from that cozy space right in front of you with unwieldy pressure gloves. Hmm. I think some sketches are in order. There we go. Do they really have forklifts that big? No... I don't think it'd fit through the doors of an LST. Probably not a RORO either. There might be a FEW ROROs with wide-enough doors, but your average RORO won't cut it. I'm thinking maybe land it near a river and then just load it onto a barge.

I almost did that, but with a SINGLE tank below, because that would let me mount the winglets even lower so that they overlapped the engines some. But this is what I went with, and it worked, so eh.

Yup, and structural. This way I could use less winglets and I didn't have to worry about three long stacks wobbling around and crashing into each other. Though there were some odd lengthwise wobbles in response to having control inputs way out on the ends of such a skinny stack...

[cont'd] Well that's convenient... Do you know how long it takes to put on a space suit? Don't bother depressurizing; if you simply displace the oxygen with halon or CO2, all you need is a simple O2 respirator to go back in and start your cleanup. Much faster response, much better damage control. Frantically decompressing chambers to stop a fire is just asking for a Soyuz-11 repeat - not to mention your couple of suit-clad space-firefighters are just BEGGING for an embolism. That'd be pretty handy if you could get it to work right. Have full hardsuits ever been tested in a vacuum before? I kinda wonder if the pressure might cause unwanted breakout friction that might make fine movements difficult. The bearings are a tough point too, since the fact that they must be completely circular necessitates a bulky design (and the biggest reason why hard gloves are simply impossible), though that's not nearly as big an issue with our pod concept here. What about one of each? A clampable hardsuit arm on the right, and a soft arm on the left for when you need to reach through a tight spot or whatever. I guess. I can't see how they could do anything a simple tether couldn't, though. But I guess you'd need to be able to REACH your feet in order to connect a tether to them, huh? Heh, nah. It's like my dad always tells me when I try to hold more than one tool at once instead of walking back to the toolchest: don't cripple yourself with tools you don't need. Is it THAT inconvenient to carry a driver in a pouch near your belt? I thought so. What I'm not sure about is where to put such an airlock. The front would be the most accessible place of course, but then you'd have to compromise between size and obstructiveness (unless you made it a modular, external chamber you could just clamp on when you need it...) Heh. Somehow I doubt they're too eager to buy something that won't fit in their airlocks. Not yet, anyways. Well, they SHOULD be able to recover the first stage, no problem. They have no delusions of reusing EVERYTHING - it sounds like their plan is to recover what they can, look at what got destroyed, decide if its worth protecting next time or just replacing, and making the appropriate changes. Given that 10-40% of the mass of an uncontrolled satellite reentry typically reaches the surface, they should be able to get at least SOMETHING back - even if it's just a few bits of hardware here and there. Everything's marinized already, so reentry's the only concern they're currently exploring - first the lower stage, THEN looking at adding the systems to recover the upper stage. And cork actually might make a decent TPS; it should ablate well (for its weight, anyways), it WILL insulate well, and as long as it doesn't disintegrate too quickly from the pressure and heat (the insulation should help with that somewhat), it could theoretically be up to the task if you used enough of it. An F-350 weighs around three or four tons. A typical commercial aircraft tug weighs around fifty tons, with a towbar capacity of thirty tons (keep in mind tugs have to deal with not only rolling friction, but inclined slopes as well). An empty S-II weighs about fifteen tons. The maximum gross weight of a typical twenty-foot shipping container is thirty tons. Equipment capable of moving an empty S-II is far from uncommon. Does that look like a dry lakebed to you!? Here, have a closer look: Well, there's something to be said for that... How about landing it next to a railway?