rdfox

For the record, I'm in favor of the part diameter convention; it's the same as is used in real life, where rocket parts are described by their diameter, since that's the critical measurement in two major concerns--mating them with other parts, and the roof height required in the building where they're constructed (since *every* rocket stage I've ever heard of was built horizontally, as it's easier and safer than trying to build it vertically, even if you don't consider that you'll have to tip it horizontal eventually to ship it to the launch site). Indeed, that last one is a limiting factor on the size of American space equipment to this day; the Michoud Assembly Facility at the Stennis Space Center is the only factory in the world that can handle building booster components up to 10 meters diameter--and that's ITS hard limit, since it was designed and built to assemble the 10-meter S-IC and S-II stages of the Saturn V. Any booster with a larger diameter than that would require an entirely new facility for stage assembly, which would cost an absolute FORTUNE and probably a decade's worth of regulatory red tape before you could even break ground on it. I'll also note that there was a proposal in the late 60s to build future Saturn V-derived boosters that replaced the existing S-IC stage with a cluster of four "260-inch" solid rockets; those would be 260-inch diameter, roughly 22 feet and resulting in a somewhat thicker first stage. If memory serves, these motors ended up being the basis for the big ones used as SRBs on the later-model Titans, Deltas, and the Shuttle...

For getting Explorer I into orbit, there's a very simple solution that's not *that* far off of what they did in Real Life. First, accept that you're not gonna get a circular orbit. (This is actually BETTER for science, because the elliptical orbit you're going into is one that will net you geiger counter data for both low- and high-altitude Kerbin orbits, assuming your battery holds out.) Then, you launch with a fairly efficient gravity turn (I recommend holding vertical to 7.5 km altitude, then turning 5 degrees every 2.5 km increase in altitude until you're either horizontal or reach 70 km altitude, whichever comes first--if you aren't horizontal by 70 km, since you're now out of the atmosphere, turn horizontal immediately) and thrust until you achieve an apoapsis of at *least* 100 km. You'll probably not hit it that exactly, as there's a good chance you'll need to use the first two solid-fuel stages to get Ap. that high, but that's not critical--you just want to make sure it's comfortably outside Kerbin's atmosphere. At this point, you can, of course, jettison any remaining spent stages, and wait for apoapsis. (This is a good time to get your low-altitude Science data, before the battery is worn down by maneuvering.) Once you're at apoapsis, aim prograde and fire your remaining solid-fuel stages. (For me, this was just the last stage, but if you're better at hand-flying gravity turns, you might also have the Sergeant-3 stage left, too.) Hold your nose prograde until the motor burns out, and congratulations, you should be in an elliptical orbit of roughly 100-200km periapsis and about 1000-2000 km apoapsis! Remember, you're not going for a pinpoint accurate orbit with it--Explorer I wasn't about nailing a precise orbit to get the best data, it was about getting something--ANYthing--into LEO to try and regain face after Sputnik and the Vanguard launch failure. That it had an apogee that had it fly through the Van Allen belt was merely a bonus; getting it into orbit, ANY orbit, and beeping away to prove it was there, was the real goal of the mission. I'm not sure of the exact trajectory flown, whether they launched it on a direct-insertion trajectory (where you just burn all the way to your final orbit in a single burn) or if they used a mechanical timer to delay firing the last stage or two until predicted apogee, but either is possible, and I personally would have chosen to use the latter; with the known (planned) course at cutoff of the last stage before final orbital insertion, a rather simple inertial, sun-seeking, or horizon-seeking guidance system could have been used to conduct a planned turnaround of the spacecraft immediately after separation, which would then solve the issue of making sure the final motor's delayed burn was in the correct direction, and we already had such simple inertial guidance systems... they were what was used to steer the launch vehicle on its preplanned trajectory, after all. (Simple being a relative term, in that they didn't need to be able to detect any form of acceleration, only detect vessel attitude compared to reference axes--THAT part can be done with a couple of gyroscopes; just about every airplane that's flown since the late 1920s has had that sort of IMU in the form of the Artificial Horizon, which just uses a coffee-and-sandwich-fueled voice-activated electrochemical autopilot to maintain the target attitude. Basic three-axis autopilots that could hold a selected pitch, heading, and bank angle--a.k.a. pitch, yaw, and roll--were commonplace on large aircraft by then, so if all else failed, you could purchase and adapt one of those...)

Random suggestion for you, Frizz, and I won't be offended at all if the answer is "aw HELL no!"... One of the more unique features of the Mercury spacecraft was that it would separate the heat shield from the main spacecraft after the parachutes had fully deployed, letting it descend a few feet and inflating an air bag that connected it to the spacecraft and acted as a landing cushion. With there now being inflatable bags available for KSP (with the Kerbin Cup mod) and someone having thus already used those to provide Sojourner/Spirit/Opportunity-style landing bags as a mod part, maybe the time would be right to add a simulation of the Mercury landing bag to FASA?

Promised myself after the STS-107 accident that I'd make it to the Cape to see a Shuttle launch before the end of the program (I was born a year after Apollo-Soyuz, so the Shuttle was *the* manned space program to me, emotionally). Cut it close, but I managed to make a two-day "banzai run" drive down to Florida (550 miles a day is a LONG drive, particularly when you're driving solo!) in time to get there to see STS-135 launch, from the beach in Titusville, along with a million of my closest friends. To this day, I regret choosing not to pay the hundred bucks to get the VIP pass to watch from the Apollo/Saturn V Center (the home of the famous seven-segment display countdown clock) and be just 3.5 miles away instead of ten, but at least I made it down to see one... even if it WAS the very last one. (I have family living relatively nearby, so had it been rescheduled for a relatively short delay, I'd have stuck it out to see the launch; delays of months, however, would have almost certainly killed my chances of seeing it at all.) Hopefully, I'll be in a position to be able to get the VIP pass for the first or second SLS launch; I really want to experience the whole ground-shaking, guts-vibrating, feels like your eyeballs are about to pop out of your head, deafening volume you get at that relatively close range. Where I saw STS-135 from, between it being ten miles away and the breeze blowing from behind me towards the pad, it really wasn't any louder (perceived) than the F-16s circling nearby to make sure nobody wandered into the launch area with his Cessna...

For the record, if you're REALLY looking for detailed nuclear weapons effects calculators/simulators, there are a number of them out there that, while they don't give you pretty pictures, they *do* give you detailed numbers regarding what damage a given device would do. First off is this: http://www.alternatewars.com/BBOW/ABC_Weapons/Nuke_Effects_Calculator.htm It shows quite a bit of generic information for a given weapon yield, but doesn't do much to explain what it means (most people don't know how much overpressure does how much damage, for example). Next up, we have http://www.globalsecurity.org/wmd/intro/nuke-effects-calc.htm . This has some interesting interpretation information on it, but it doesn't give very much calculated data, and focuses almost entirely on fatalities, with little detail on effects on structures. Finally, we have the Big Daddies of the nuke calculator world, from Carey Sublette's Nuclear Weapon Archive (home of the Nuclear Weapon FAQ--highly recommended reading if you want to write about a nuclear war!), we have this: http://nuclearweaponarchive.org/Library/Nukesims.html That actually contains three separate calculators. The first is an Excel spreadsheet of blast and thermal effects; I've never used it, since I don't have Excel, but it's reputedly quite good. However, the ones I really recommend are the other pair of calculators, a couple of closely-related programs used (possibly to this day!) by the US Defense Nuclear Agency, which calculate the effects of nuclear (and, for BLAST.EXE, non-nuclear) explosions. They have a wide range of capabilities and a LOT of options for customization of the simulated burst (read, re-read, and re-re-read the help screens, because they provide huge amounts of useful documentation for this!), including the type of weapon (pure fission, boosted fission, or fission-triggered fusion, and different efficiency categories for each, plus "clean" and "dirty" configurations for the fusion weapons), the burst height, and the type of surface at the burst point (used in calculating cratering effects). However, because they *are* DOS programs from 1984, they aren't the most user-friendly. However, they should run in any version of Windows I know of (not sure about 8, but I know that up through 7, you can run them). Note that the burst height setting is also one of the most important in there; most of the calculators out there "assume optimum burst height," but the definition of "optimum" varies depending on what you're trying to maximize. These calculators generally maximize the 5psi blast radius, to provide maximum casualty numbers. While this may be appropriate for some targets (particularly if the war goes into a countervalue mode where you're attacking cities and industrial sites rather than military targets, and for airfields without Hardened Aircraft Shelters), most nuclear weapons targets are highly hardened and would require a different (lower) burst height, to maximize the radius of the pressure curve that would cause failure of those targets. Some examples would be how most US nuclear missile silos are reputedly hardened to withstand an overpressure of 500 psi, while some Russian silos are hardened to 2000 psi(!); the US silos would require a very low burst height indeed, while the Russian ones would almost require that the silo itself be caught within the fireball, mandating a surface burst to destroy them. Likewise, command and control bunkers would generally require surface bursts to dig them out and collapse them. While all of these (except the Excel spreadsheet and BLAST.EXE) provide some estimates of fallout radius, that isn't entirely accurate, as they don't account for downwind drift of fallout and really only show the short-term fallout zone, not the areas that would be contaminated in the 6-36 hour period. Also, *none* of these (and as far as I can tell, *no* publicly-available tools) provide prediction of the effects of high-altitude bursts intended to generate EMP effects; the best rule of thumb there is to use geometry to find the line-of-sight radius to the burst and then assume that all non-hardened solid-state electronics within that circle are fried. (Radiation/EMP-hardened electronics, like used by military forces, and old-fashioned vacuum tube-based hardware can both survive within that radius, but if they're close enough to the burst point, then the induced currents in the copper wiring itself will still fry it. Again, just a rule of thumb, but I'd say about a 150-mile circle around the burst point would have high enough EMP to do that.) Of course, there are four truly important things to remember when writing your hypothetical war's target list and weapons allocations: 1) What is the target each weapon is being used for? Unless it's either the 1950s (with the doctrine of "Massive Attack" in place), a punitive retaliatory strike by a nation already devastated by an attack, or a madman terrorist out to kill as many people as possible, cities will generally NOT be targets. "Countervalue" strikes (i.e., strikes aimed at industrial infrastructure and the civilian population, meant to devastate the recipient's economy and chances of postwar recovery) are not only distasteful and quite possibly war crimes, but they're also inefficient in the use of weapons, particularly as a first strike option, as they leave your enemy entirely capable of responding in kind. "Counterforce" strikes (i.e., strikes aimed at "blunting, reducing, and degrading" the enemy's warfighting capability in general, and nuclear forces in particular) are seen as vastly preferable, as they not only have the potential for limiting the level of violence employed (ICBM silos, for example, tend to be located in thinly-populated agricultural and undeveloped areas, so hitting them causes relatively few casualties), but every successful strike decreases the enemy's capability to retaliate. (Command, control, and communications centers also fall under "counterforce" targets, though they tend to be located in closer proximity to population centers, as do airbases and submarine bases. However, even those would likely generate less violent retaliation because of the presence of obvious military targets being struck at.) The first step is to determine what targets need to be hit, and ranking them in priority so that you know which wave of attacks they're hit in. (Again, economy of force and controlling the level of violence to try and avoid spiralling out of control into Armageddon are keys to selecting waves of strikes, as the idea is that you launch a strike, then there's a pause as you give the enemy a chance to surrender before launching your next wave.) 2) Once you have your target list completed, you need to know what sort of effects are required to destroy each one. This has a direct effect on how you attack it. 3) You then need to determine the burst height that maximizes the radius of the effects curve matching that. If a given weapon's ideal burst height for a given target results in an effects circle smaller than the Circular Error Probability of the weapon (a measure of accuracy; CEP is defined as the radius around the aimpoint within which there's a 50% chance of the weapon actually hitting), then you almost certainly need to select a larger and/or more accurate weapon. After all, if the odds say that the weapon will land far enough away from its target to *not* destroy it, there's not much point in firing in the first place! (Note that accuracy is likely better than yield; the US no longer stockpiles the 9-megaton "city killer" warheads used on the Titan II ICBMs, or even the 1-megaton warheads used on early Minuteman ICBMs, instead preferring strategic weapons in the 125-550 kiloton range with much greater accuracy, as it's possible to have many more of them. Likewise, for "soft" area targets like cities, simulations have shown that it's more cost-effective, in terms of building the warheads, to blanket them with a pattern of smaller weapons than to try to use a single huge one. We do still have some weapons up to 5 megatons or so, but those are for special purposes like digging out deep command bunkers with a series of surface bursts. Russia still has a limited number of 20-megaton weapons that were specifically designed to collapse Cheyenne Mountain, but those are similarly special-purpose weapons, and efforts since 1970 or so in all nuclear powers have been more towards increasing the weapon accuracy and decreasing the warhead size.) 4) Once you've determined what your target is, how "hard" it is, and what the appropriate weapon and burst height to destroy it are, you have one last major consideration--what is the reliability of the weapon system? Just how likely is it that the whole thing will operate as planned and put the warhead within the CEP circle? Manned bombers, for example, are extremely good at putting the weapon on target--IF they can get past the enemy's air defenses. Ballistic missiles, on the other hand, are more likely to suffer random errors (particularly due to the winds aloft during boost and entry) that throw the weapon off-target, but are very hard to defend against. Cruise missiles combine the worst of BOTH worlds(!), albeit with some amelioration in each (small, hard-to-find targets for air defenses, and their autopilots will correct for wind drift to some degree). All options have a nonzero chance of failure of the delivery system (ICBM/SLBM blows up during boost, cruise missile autopilot has its gyros tumble and dives into the ground, manned bomber's crew is killed by radiation from a nearby burst or just plain gets lost, etc.), and there's also a small, but still nonzero, chance of the weapon itself failing to function at all, or of fizzling and not producing full yield. Once you figure out the odds of everything working right, getting the weapon to its targeted burst point and the weapon firing as designed, you can then use that to work out how many weapons you actually need to use to reduce the target's odds of survival to an acceptably low number (i.e., "guarantee" target destruction). Again, this may end up seriously affecting the choice of weapon, as what would otherwise look like a highly attractive option might not be reliable enough to be viable given the size of your inventory--particularly if you're in a situation where political authorities have authorized a limited number of weapons to be released. Note that you need to run all four of these considerations past EVERY TARGET to decide what gets hit, when it gets hit, what it gets hit with, and how many are aimed at it. Only after you know all these things for EVERY target on the list can you really say what the war will end up looking like. (You may also be surprised to see what you thought were certain targets end up being passed up as being too much trouble and/or too expensive in the number/size of warheads required...) I'd personally recommend that you get a copy of the old game "Bravo Romeo Delta," a US/Russia strategic nuclear war simulator set in the late 80s/early 90s, which may not be the *most* accurate out there, but playing it repeatedly will give you insight into the sort of decisions that go into nuclear war planning and help with defining your target list and weapon assignments...

Note that the Senate Launch System is not actually *required* to fly an Orion mission; the Orion can easily be put into LEO by a Delta IV Heavy, and, in fact, a prototype one is going to be flown on just that either late this year or sometime next year in a first unmanned test flight. I suspect that the SLS will end up not being much more than a footnote in history, a "wow, that's one hell of a record capability" thing that never actually gets used for anything but Congressionally-mandated missions. Simply put, even if the engineers knew the lift capability was there, there's just not really any market for putting locomotives into LEO. For missions that require a vehicle of that mass, it's going to be less expensive to launch them as smaller components and mate them in orbit, like the ISS was (albeit with significantly larger components, since expendable boosters have a better payload capacity than the Shuttle did) and like von Braun's original preferred Earth Orbit Rendezvous method of flying the Apollo program. (For those unfamiliar, it would have involved three to four launches of Saturn IB-sized rockets, one carrying the Apollo CSM, one carrying a transfer/lander stage that would dock onto the rear of the Service Module, and one or two as tankers to top off the propellants in the spacecraft before the transfer burn, docking them in Earth orbit.) Honestly, I suspect that Falcon Heavy, Atlas V Heavy, and Delta IV Heavy will end up being the sort of size range that you see the bulk of heavy-lift operations being done with in the foreseeable future; SLS is just too big for most missions, unless you want to send up an ISS replacement in just two to three launches.

As it turns out, I wasn't quite right on the exact sequence of events, as I initially got this from "From the Earth to the Moon," but I've since found details in the Apollo 9 Mission Report, found here: http://www.hq.nasa.gov/alsj/a410/A09_MissionReport.pdf It's briefly mentioned on page 5-8, as rough operation at 27% throttle and "throttle changes were terminated until smooth operation was achieved." It's also mentioned on page 9-60 as one of the anomalies in descent propulsion system performance: "c. The crew experienced a rough engine condition while throttling from the 10- to the 37-percent setting during the second firing", and again a bit later on the page and onto page 9-61: "Engine roughness was reported by the crew when the engine was throttled from the 10 to the 37 percent setting during the second descent engine system firing. The onset of roughness occurred as the throttle setting reached approximately 27 percent, at which time the setting was held constant until the roughness ceased. This roughness is typical of that experienced with helium ingestion into the combustion chamber. The roughness lasted approximately 2.5 seconds (see figure 9.8-2) and the remaining portion of the second firing and all of the third firing appeared nominal." A detailed summary of the anomaly is found in section 17.2.11, starting halfway down page 17-35 and ending about a third of the way down page 17-36. Apparently, testing showed that there was no detrimental effect from suffering helium ingestion, and therefore, no corrective action was taken. I'm sure some discussion of it can also be found in the mission transcripts, but I am *not* gonna go trawling through THOSE right now...

For the record, the Apollo LM *did* demonstrate the need for good ullage in hypergolic engines. It used hypergolic engines throughout (for reliability), and during the first manned test flight (Apollo 9), the initial burn of the throttleable descent engine was started at 20% thrust. The crew reported a very rough ride and shut down the engine, but on a hunch, they tried again at 40% thrust for startup and found that it was very smooth, and they could reduce the throttle to the minimum setting without gaining roughness after starting at the higher thrust setting. Their verdict was that, most likely, the lower thrust setting at startup didn't provide sufficient ullage thrust to prevent the engine from swallowing some helium, resulting in pogo-style oscillations and a rough ride. From then on, the standard procedure was to start the LM DE at 40% thrust or higher, then reduce thrust to the desired level, since this would stratify the propellants from the pressurization helium enough to provide a smooth burn. (The RCS ullage, apparently, was just enough to get the engine started, but not enough to ensure there was no helium swallowed by the engine. This wasn't an issue for the CSM's SPS engine or the LM Ascent Engine, since both were non-throttleable designs that were sure to generate sufficient ullage for stratification, and, in all but the landing abort contingency mode, the LMAE had the benefit of lunar gravity to provide zero-charge ullage...)

When I'm collecting Science, I tend to create a standardized design for my unmanned probes and for my manned landers, and use that over and over to collect points with minimal effort. (This is also quite realistic, at least in the earlier phases of the space program--note the use of nine Rangers to three designs, seven Surveyors of a single design, five Lunar Orbiters of a single design, 11 Pioneers of about five designs, two identical Voyagers, two identical Mariners, and, of course, on the manned side, six Mercuries of essentially one design (only the hatch, a separate piece, changed, to incorporate a proper window), ten Geminis of two designs, eleven Apollo CSMs of two designs, and nine Apollo LMs of four designs flown, not counting unmanned test flights of the manned spacecraft. Also note that on the manned side, the design variants basically were relatively minor internal changes; only the Rangers and Pioneers saw spacecraft of vastly different configurations fly in the same program...) Also, when using FASA, I tend to standardize on real-world boosters as much as possible, and simple extrapolations from them when I need something else. (For example, I've been launching Gemini spacecraft to land on Kerbin's moons using a Saturn IB with SRBs, since I need about 1km/s more delta-V than the standard IB has to offer. Given that NASA seriously considered the use of strap-on SRBs on evolved Saturn V boosters, I consider this a plausible line of development, particularly as an interim booster until the S-V is ready.)

Not counting being the first documented case of getting out and pushing (which resulted in my designing with a 10% delta-V budget safety margin from then on!), my closest would be my old standard large modular interplanetary transfer stage's launch vehicle, which would put the transfer stage module and its orbital maneuvering tug into LKO with 8 m/s left in the top stage, reliably. (I would then dock the transfer stage to the spacecraft, and as many additional stages as necessary to it for a parallel-burn to get as much delta-V as I needed--hence modular, as I ended up with big square blocks of these things...)

Nononono, that's not the right chant, Fels. It should be... Seroslupmi sám!

Has anyone noticed a weird problem with the Apollo LES? Specifically, if I rotate it 45 degrees counterclockwise compared to its initial position, so that the BPC hatch lines up with the CM hatch, when I place it, it sort of "sinks" into the CM and then can't be dealt with in any way, shape, or form except by deleting the entire command module and starting over. Can't even select it with a right-click or in action groups, much less remove it. Also, my tip of the day, for those who both use MechJeb and want to try to have a more realistic/difficult experience with the Saturns. The Saturn Instrument Unit that guided the vehicle during ascent used "closed-loop" guidance during first stage burn (S-I, S-IB, and S-IC), then switched over to "open-loop" guidance after staging and second stage ignition. Basically, this meant that during the first stage burn, the vehicle was flying a completely preplanned guidance program with no regard to outside input except for what the IMU was saying about heading and deck angle (angle relative to the ground); once the second stage was running, it switched to guidance that would actively fly the booster to follow the preplanned optimum trajectory rather than just following preprogrammed guidance commands. This can be simulated by turning OFF MechJeb's "Corrective steering" option in the Ascent Autopilot before launch, and then turning it ON again after second stage ignition. This results in a more realistic flightpath (no hard pitchover to start the turn, then pitching back once it's going), and it also provides a bit more difficulty in that it's slightly less efficient in terms of delta-V. (Something in the 200m/s range for the S-IB with an Apollo CSM, in my experience.) This can also be applied, for realism, to the earlier boosters--I know that Redstone and Atlas used entirely closed-loop guidance, and I'm not sure about the Titan II, but I wouldn't be shocked if all the Titans used closed-loop guidance for at least the first stage...

And from the new Abridged Edition... Kerbin Mostly harmful.

Sleeping and snacking.

Hey, Frizz, I know you don't take requests, but I had an idea for a very simple (probably less than half an hour's work) part that could be useful for certain applications, like rovers and such, and would also fit nicely into the Space Race feel of FASA. It's just a simple little box, probably about the size of the PresMat barometer or the Gravioli detector, that has only one purpose: It's a container that holds Science data. This would be beneficial for simulating Apollo J missions (the ones with the LRV), because it would allow you to hit more than two stations on a single EVA without having to return to the LM to drop off samples and crew reports; instead, you could just store them in the box on the rover and bring them all back in a single trip. (This would also be similarly valuable for a minimalist manned Eve landing, since it would allow the use of MOOSE/LESS-style external seating.) Just a suggestion, not pushing it or anything--only reason I haven't done it is that I can't afford 3D modeling software, much less the time to learn it. For those who were clamoring for Minuteman first stages to use as SRBs on evolved Saturns, the smallest of the three stock SRBs is actually very close to it in size. Going by Encyclopedia Astronautica, the Minuteman-1 (TX-55) stage proposed as such would scale down to about 1.1m diameter, and 4.8m tall, which is quite close to the size of the RT-10 (1.25m diameter and looks to be about four times that in height, so about 5m tall). You'd need to do a configuration edit, however; using the 64% rule three-dimensionally for mass, you end up with the TX-55 scaling down to 6.05 tons full mass, 0.6 tons dry mass, and 207.4 kN thrust. The TX-55 had an Isp. of 237s surface, 262s vacuum, and a total burn time of 60 seconds. So if you hack the .cfg for the RT-10, you could get a very close TX-55 clone to use on your evolved Saturn MLVs. And now, off to KSP, to work on that crewed Eve return. I think I should be able to get a nice minimalist two-man spacecraft to low orbit if I can land a fully-fueled Saturn V-Transtage and keep it upright...

Short version, when you fly a rocket several THOUSAND times (the basic R-7 booster that, with upper stages, is still used as the Soyuz booster has been in continuous use since 1957, and the Proton since about 1965), even after the early "working out the bugs" phase, by the nature of rocketry, you're going to lose a few--no mechanical system can ever be perfect, and while a flaw that slips past quality control in a car, for example, may see the engine die and leave you stranded at the side of the road, in rockets, failures tend to cascade, and cascade RAPIDLY, usually resulting in Rapid Spontaneous Unplanned Disassembly. The R-7 and Proton series are both extremely reliable workhorses (the R-7 in particular, as it's the only booster the Soviets/Russians have ever man-rated), comparable in reliability to the Delta series, the post-1963 Atlases, and the Titans. (Nobody has ever matched the reliability of the Saturn series, which suffered all of *two* major non-catastrophic failures in its entire flight history--Apollo 6 had the two engine failures in the second stage and the pogo-induced failure of the third stage to relight, while Apollo 13 had an early second stage second-engine cutout, but neither of these ended up being mission-killers, as the booster was able to compensate with extended burn times and, on 6, the ground controllers saved the mission by using the Service Module engine to fly a planned alternate mission after the failed second burn ignition. However, there simply WEREN'T very many Saturn launches to begin with--ten Saturn Is, nine Saturn IBs, and 13 Saturn Vs--so with such a small sample size compared to the number of launches that just about every other major launch vehicle family has flown, it's really hard to say that you have a representative view of the vehicle's reliability; even the Shuttle flew four times as many missions as the entire Saturn family.) If I had a payload that really, REALLY needed to get into orbit without worries about a launch failure, I'd certainly put the R-7 and Proton on my shortlist of booster options. (Yes, I'd take out an insurance policy against a launch failure anyway. I'm an engineer; I like to have my contingencies covered!)

Modular systems are a major aspect of this, as NASA plans to offer to rent LC39 to any launch service provider that cares to shell out the required money. Indeed, it was recently announced (14 April 2014) that NASA had signed a contract for a 20-year lease of pad 39A to SpaceX for Falcon 9 v1.1 and Falcon Heavy launches, including the use of a horizontal assembly facility adjacent to the pad itself similar to that used CCAFS SLC-40 and VAFB SLC-4E. Plans are to use a new launch pedestal that they'll build atop the existing pad, rather than a mobile platform, and to use the existing Shuttle-era Fixed Service Structure, extended to accommodate the longer boosters' requirements. Presumably, they'll be either installing a new hammerhead crane atop the FSS, or building an equivalent to the old Apollo Mobile Service Structure, since SpaceX's contracts with the Defense Department specify vertical integration of payloads rather than horizontal. The anticipated first SpaceX flight from 39A is the first Falcon Heavy launch, currently scheduled for sometime in 2015. 39A will also be the sole planned site for Dragon Rider launches, as it's easier to man-rate its modified configuration than man-rate SLC-40. 39B will be, for the foreseeable future, the pad for all launches that use the VAB, including all SLS launches and launches by any commercial provider that cares to rent it during the (currently very long) slack periods when it's not needed for SLS operations.

For the record, lower-stage explosions *do* occur with hot staging at times; one example is the launch of Gemini 10, where the first stage oxidizer tank ruptured just after staging, because thrust impingement on it from the second stage caused it to overpressurize and burst. However, it's not really that much of a worry. After all, even with the violence of a tank bursting, the debris wouldn't reach the upper stage--it's already overpressurizing due to thrust impingement from the upper stage, and any of the debris that IS driven upward by the tank failure would be getting blown straight into the exhaust of the upper stage engine, which would pretty much instantly stop it and send it back down away from the upper stage. Any that has enough horizontal velocity to not get blown back away with the exhaust would be flying at an angle that doesn't pose a threat to the upper stage.

Yeah, just about every one of those slow-motion cameras that were (and still are!) used to pick out details of rocket launches and flights aren't there for PR value; they're there to record important processes for engineering analysis after the flight. The engineers can pick a *lot* of valuable information on how the systems performed from those films, which is why, for example, the Mobile Launchers and LC39 launch pads themselves were just *covered* in high-speed 16mm and 35mm motion picture cameras that started at about T-9 seconds, when the ignition command was sent to the booster, and filming the entire ignition and launch sequence, including a rarely-seen but truly awe-inspiring shot *up the throat of the Saturn V's engines* from *inside* the flame trench. (Shuttle didn't have that angle because the SSMEs were above the top level of the Mobile Launch Platform and thus could have their startup behavior recorded from the sides, but with the Saturn V's engines sticking down below the platform top, the only place to film their startup behavior was from below.) The S-II didn't just carry staging cameras for the S-IC jettison on SA-501 and SA-502 (Apollo 4 and 6), it also carried staging cameras for S-II jettison on those flights, looking *up* to show how well it separated from the S-IVB. Since the S-IVB did the "heavy lifting" in terms of getting the spacecraft up to orbital velocity (the S-IC was basically for initial loft, to get out of the atmosphere, and the S-II was more for the gravity turn and starting to push apogee around the planet), the S-II Jettison staging cameras didn't need any sort of retrofire engine to deorbit, though their thermal protection system had to be much more robust than that on the S-IC Jettison cameras due to the higher speed and altitude when they were ejected. (For the record, the pad- and Mobile Launcher-mounted cameras were, to survive the environment they were going to be in, mounted in heavily shock-, blast-, and vibration-insulated boxes, with the pad- and deck-mounted cameras buried inside the structure for further protection, while the tower-mounted ones were well back, ideally on the tower itself rather than a swingarm, and used the then-brand new technology of fiber optics to transmit light from the half-inch thick quartz lenses to the actual camera.)

My comment about the workaround isn't for docking with the half-meter docking port, it's for docking with the Agena docking port. THAT'S the one where the funky collider mesh gives MechJeb fits.

Side note, anyone using FASA *and* MechJeb should know that the docking autopilot only reliably works in one way for the Gemini and Apollo docking ports. With the Gemini/Agena docking arrangement, attempting an automatic docking to the Agena docking port will see the Gemini try to dock at right angles to it, if you use the Gemini as the "hunter" in the arrangement. Having the Gemini stay put and the Agena attempt to automatically dock with it will resolve the issue just fine; it docks correctly. With the Apollo docking gear, it's the same--attempting to automatically dock the probe-equipped vehicle to the drogue (cone)-equipped one will end with an attempt to dock at 90 degrees to the docking axis; however, having the drogue-equipped vehicle automatically dock with the probe-equipped one will work just fine. This is not a bug report (it's long been known that the funky collision models needed screw up MechJeb when it comes to auto-docking), just informing people. There's also another workaround using MechJeb, so long as both spacecraft can be controlled at the time (meaning that you need a probe core in the unmanned craft). First, switch to the drogue-equipped vehicle, control from the drogue, set the docking probe as your target, and activate Smart A.S.S. in the "+TGT" mode, so it aims the docking port directly at the other one. Switch back to your probe-equipped vehicle, control from the probe, target the drogue, activate +TGT, roll to whatever roll attitude you want relative to the target, and then manually close in and dock with the RCS; this makes the alignment automatic and only requires the manual approach.

NASA investigated a one-man lunar lander in connection with a "quick and dirty" landing program that would have used a Gemini spacecraft in the "CSM" role, and a one-man *open-cockpit*(!) lander in the LM role. The only real advantage of this was that it would have been able to use a much smaller booster (probably a Saturn IB with Centaur or Transtage upper stage for the trans-lunar and trans-earth transfer burns), since it would have required an EVA to board the lander, an EVA to reboard the command module, and had very limited sample-return capability, plus it would have required re-engineering the long-duration Gemini spacecraft to allow for EVAs and docking to carry the lander to the Moon. Given that Apollo and Saturn V were both well-advanced in design at the time this was proposed, it never really had much of a chance except as a possible backup option in case it became clear that Apollo wouldn't be ready in time. As for why a two-man lander, it was partly to maximize the amount of science that could be done on the surface, but there was a much bigger reason for it. Simply put, the LMP *was* basically a flight engineer on the lunar missions. Yes, he could take control of the vehicle if necessary, and, in fact, Pete Conrad let Al Bean have control over Apollo 12's LM for a few minutes while on the far side of the Moon, but the LMP's primary role during the landing was to monitor the computer and annunciator panel to keep track of, diagnose, and fix any problems (with the help of mission control) while the CDR handled the actual flying of the landing. Remember, test pilots *are* engineers; they usually have engineering degrees, and are expected to do a lot of engineering analysis of anomalies during flight to be able to work around them and bring the aircraft back in one piece. The whole thing about the "pilot" designation was that the majority of them came from single-pilot flight test environments (fighters, trainers, pure experimental aircraft, etc., where you don't work as part of a crew) and their egos didn't want to admit to being the "lesser" light in the spacecraft on a mission; the "commander" and "pilot" designation got around this by having the implication that both were equal in flying ability, but the commander was the senior officer and thus the one in charge should there be a disagreement. (Yes, this was influenced by their military backgrounds--there's always a commander, a senior officer present at whose feet the buck stops.) Indeed, on the Skylab missions, the Pilot was usually a scientist, too, with the Commander being the only "stick and rudder man" who primarily was a pilot/engineer amongst the three, but the designations were retained because NASA did require even their scientist-astronauts to become pilots who were rated in high-performance jet aircraft (in the form of the T-38). It wasn't until the Shuttle program opened the door to non-pilot astronauts that the more accurate "Mission Specialist" and "Payload Specialist" designations came into being. As a side note, the single most ridiculous position designation that NASA ever had was on the Apollo-Soyuz mission. For that, the three Apollo crew positions were designated as Commander, Command Module Pilot, and Docking Module Pilot. The Docking Module was not at all a spacecraft requiring a pilot; it was essentially just a docking adapter to mount the androgynous docking system that NASA and the Soviets had developed on an Apollo with minimal work, plus act as an airlock between the Soyuz's 14.7 psi natural air on-orbit atmosphere and the Apollo's 5 psi pure oxygen atmosphere. Really, the designation as DMP was probably a sop to keep "Original Seven" alumnus Deke Slayton (finally making his first spaceflight after it was proven that his atrial fibrillation wasn't a flight-disqualifying issue) happy as to his official role in the mission, as opposed to being designated "third pilot" or "additional crewmember" or something like that...

The X-24 was one of a series of "lifting body" prototypes of the late 60s and early 70s, which were expected to be the basis for a future reusable spaceplane, being able to fly on lift generated entirely by the body shape rather than by wings. While frequently credited as the basis for the Space Shuttle, in reality, pretty much the only thing they contributed to it was demonstration of the ultra-steep gliding approach and landing used by the Shuttle could be done with more than just the stubby-winged X-15/F-104 configuration, which allowed NASA to eliminate the planned pop-out jet engines for approach and landing, saving much weight and interior volume for cargo. That said, lifting body designs *are* the basis for most small reusable spaceplanes that are intended for carrying only people instead of cargo. As for the F-104, Mike Collins had comments on it, specifically regarding its glide ratio, actually: "The plane was designed ('optimized') for all-out speed, and it did go like hell, preferably in a straight line. When slowed down, it was simply too heavy for the amount of wing area (too high a 'wing loading'), and if the engine quit, you'd better be over the Edwards dry lake, because it dropped like a stone."

The ISS has a fairly healthy supply of recreational materials on board that the crew can--and, indeed, is *expected* to use during their designated "rest" periods (as opposed to "sleep" periods, when they're expected to actually be, y'know, SLEEPING). This includes the infamous guitar (which, IIRC, also had flown on Mir, was brought back down on one of the last flights home from Mir, and then sent up to the ISS on one of the early resupply missions), an electronic keyboard, some recreational software on the laptops (plus any personal laptops/tablets that the crews bring with them), and a DVD player with a fairly healthy library of movies, TV shows, and some sports events, with a TV display in the designated dining area (which is also the common "rec room" area) so that the crew can watch DVDs as a group. (No Blu-Ray player yet, and not likely to be one, since IIRC, the TV is a standard NTSC set instead of high-def.) Additionally, there have been some special TV broadcasts to the ISS, specifically for the benefit of the crew. I believe the Super Bowl is sent up live every year (with the US television feed, so that those who aren't football fans can enjoy the commercials), and I know that Marvel/Disney made special arrangements with NASA after Avengers debuted so amazingly hot to transmit it up to the ISS on a Sunday afternoon or evening (Sunday is a "rest day" where the only duties for the crew are routine housekeeping stuff and they're allowed to decompress after a six-day workweek) about a week after its US theatrical release, so that the crew that had been up for only about 30 days at that point wouldn't have to wait another two months to get to see such a hotly anticipated movie. (It was NASA that made the initial request!) This is, of course, in addition to the Cupola module, which, while officially justified as a post for commanding EVAs and RMS operations, was also specifically and officially identified as a place for the crew to be able to get away from each other and do recreational Earthgazing. This heavy emphasis on recreational facilities is, at least on the NASA side (not sure on the RSA side, though their experience with the Salyut series and Mir would almost certainly have parallels), due to experience with Skylab, where, as was typical, NASA planned the missions to pack as much work into the available flight time as possible--working 16 hours a day, seven days a week, no days off, minimal breaks, running a million miles an hour the whole time you're on the clock, and expected to just drop off instantly when your sleep period starts, and then instantly snap completely awake at the end of the sleep period and get straight to work. While people can live that sort of schedule for a short period of time and be productive, once you get beyond about two weeks of that, you start getting severe burnout, productivity falls off, people start making mistakes, and stress levels start to make people very unhappy indeed. (The US Navy may have seven-day workweeks at sea, but even there, they do, at worst, "port and starboard" watches, twelve hours on and twelve hours off, where you at least have SOME time to rest and decompress after your shift, and to wake up and get functional before the next one.) The net result of that schedule was that the third (last) Skylab crew actually revolted against mission control during their 93-day flight; about halfway through it, the stress got to the point that they simply decided amongst themselves that they would take a day off, and simply sent a flat transmission to that effect down to the flight controllers, then shut off their voice radios for 24 hours. (They left the telemetry radios and biomedical monitor radios on, so that the ground would know that they were still alive and not in trouble, though.) They then proceeded to spend the day doing nothing of value beyond the mandatory housekeeping chores (like, for example, changing lithium hydroxide canisters). The ground did realize why this happened and reshuffled the flight plan to give them a bit more time to decompress for the remainder of the mission, but it still resulted in all three men being "blackballed" from the flight roster for the insubordination. However, it also sharply pointed out to NASA that they needed to re-examine their concept of crew management for long-duration spaceflights. What does this all add up to? Well, my suspicion is that any manned Mars mission will have a similar sort of recreational facilities. The physically-present purely recreational items will probably be things like a guitar and a keyboard, and maybe something akin to a Wii or Kinect or other game console with motion-capture capability, though the last is questionable. There will certainly be some sort of video media player (whether it's disc-based or based on computer video files is open to debate, though a computer-based one could certainly be updated with new videos during sleep periods, which would be valuable on a two-year mission) with a relatively large display for communal viewing; I suspect that there would also be a wi-fi link that would allow the crew to watch videos from that player on personal tablets or laptops so that they could watch videos privately, too. (Be they video messages from their family, or just a case of something they like watching that the rest of the crew can't stand.) Any game console would also likely use the same large display, but I suspect that personal gaming devices (think a 3DS or other handheld) that can network with each other would be more likely, simply because they would allow for use of the video player while people are gaming; these might well be integrated into the tablet/laptops to save mass and volume. If it was felt that a "tabletop" game experience was necessary (i.e., for board games) instead of using virtual ones on screens, it would likely either be in the form of magnetized "travel" games as mentioned above, or in the form of "virtual" versions using a holographic display, which would have the advantage of allowing a much larger game collection and no loose pieces to get sucked into the ventilation system filters or otherwise lost. This could even be combined with a motion-capture system to allow the crew to move pieces and even roll dice without resorting to control buttons; if it was felt necessary, it could probably be built into the "dining room table" that the crew would gather around for meals, saving on volume by making the table as dual-purpose as real ones are for tabletop gamers. That said, I don't expect there to be any place for the crew to engage in large-scale physical recreation, unless you count running on the treadmill or riding the exercise bike as "recreational." The volume required is just excessive, and even in zero-G, the risk of serious injury is too great. (Besides, much of the attraction of ball-type sports is judging the arc needed to throw the ball where you want it to go; during the coast phase of flight, that'd be horribly boring for the crew, since there's no actual arc, you just push the ball in the direction you want it to go. That said, I could totally see someone smuggling a Nerf mini-football on board to toss around for the cameras during an EVA on the surface of Mars...)

It wouldn't. I was suggesting it might end up being the alternative solution for the US's high-level nuclear waste disposal problem, since Yucca Mountain isn't going to happen. (Also, we *have* done that before; the US government shipped a whole BUNCH of fissile material from decommisioned Russian nuclear weapons to the US to be reprocessed into fuel elements for civilian power reactors, specifically to make sure it didn't end up in the hands of rogue states and/or terrorists...)