wumpus

You might want to come to Washington DC and peek in the Apollo 11 capsule. That is not a large area, and except for the brief period when they were in the LM and/or on the Lunar surface, all three were crammed in there. I understand the ISS people get tired of only seeing the same five (or so) people, but there at least is a way to get "somewhere else". In an Apollo spacecraft* you pretty much were next to two other astronauts for two extremely critical weeks. There simply was no time to deal with friction. * Micheal Collins was clear in "Holding the Fire" that only the Mercury program used "capsule", although that was a cockpit you barely fit inside [and only small astronauts were even considered]

I knew a few of the engineers on the Apollo program* (probably junior engineers during the design, although retired by the time I met them) and one of them had driven Armstrong and Aldrin somewhere and would only say that "one was a gentleman and he wasn't impressed with the other". It didn't take a whole lot of digging to learn who was who. I suspect that if Collins (or Armstrong) had a real issue with Aldrin, they wouldn't have had to spend a couple weeks in a small can with him. Astronauts get crabby enough as it is (still reading "Packing for Mars", which discusses this) and it would be dangerous to have real personal problems during flight. * not NASA. They worked for Martin. Which eventually merged with every other aerospace firm to become the Lockheed we know today.

The Apollo 1 fire. The schedule was set to have Pete Conrad as the first man on the moon until Apollo 1 delayed everything by a year and completely upset the schedule. Also after that Gemini flight, nobody was worried about Neil's ability to handle flight decisions (both making the decisions and carrying them out) under extreme pressure. He was never seen as the best "stick man" in the X-15 program, but certainly one of the first choices in something like the first trip to the moon, and that was probably enough to keep them from reworking the schedule to put Pete back in command of the "first" mission.

Being able to handle stimulus and response is enough for a Senate job. They have staffers for any other duties.

One of his main competitors owns the Washington Post. Stories that run there tend to be considered "real news" and run elsewhere. Or he might be using an ancient troll, who knows.

if 700mm is the diameter, then you are dealing with more than 2m of tire with a moment of inertia based on a .35m radius (considerably bigger than most car tires). So weight certainly matters. But wearing out 5 times faster might not justify that. But if there is one thing on the whole bike you want light, it is the tires (of course, it defeats all the benefit of lightness when you have a flat).

Try this: https://en.wikipedia.org/wiki/Freewing_Scorpion (note that specs refer to the larger craft built by Scaled in the Mohave, the smaller one was being built in Maryland). http://stargazer2006.online.fr/unmanned/pages/scorpion.htm (apparently the key was to remove both Scorpion and Scaled and stick with freewing and Rutan for searchterms).

Long, long ago I worked for a company working with scaled composites to build drones [a novel unmanned aircraft, not some helicopter variant, although it could take off and land in a *very* small runway] (sometime between the first and second wars in Iraq. Unfortunately a major partner was a French military company and it didn't go anywhere). Anyway, I was shown one of the early prototypes that was made out of Kevlar. It had survived hitting a tree. Kevlar might not be officially "strong", but it is very, very tough. It also took far too long to cut and fabricate and they went back to fiberglass. Note that the link below appears to be in Russian (or at least other Cyrillic using language), but the picture and untranslated parts appear to match. [snip]

Rockets and People: Boris Chertok’s books on 60 years of the Russian Space program (I bogged down in volume 2, but am glad I've read at least this far). https://www.nasa.gov/connect/ebooks/rockets_people_vol1_detail.html

You probably want to find somebody with a CNC machine (I'm guessing colleges, especially any with a mechanical engineering program would be a good bet). The other idea would be to find a way to use the 3d-printed material as the basis for casting (either as a "lost epoxy" system, or a mold for a "lost wax" positive. I suspect "lost epoxy" doesn't work or it would be a lot more popular).

It is certainly a massive rocket built out of Shuttle parts, but if they started after Buran was canceled I'd expect 6 times the cost of SLS would have been a large part of what bankrupted the USSR. Being six times the trouble would be impressive, but I don't think I've heard of it. I'd also expect the engine parts are somewhat available, aren't they using half-sized [RD-180] (and possibly quarter sized) engines currently? Of course resurrecting the rest of the rocket is probably starting from scratch.

Falcon 9 is doing reuse at least as well as the Shuttle was sold on, and likely doesn't reduce costs by more than 2/3rds, hardly "orders of magnitude". The army it takes to launch any major rocket is still an issue, making re-use merely "one technique of many" needed to reduce costs to your level. It still isn't clear that a "big dumb booster" couldn't be just as inexpensive. It isn't obvious how you would do such a thing, but then again retropropulsive landing didn't seem obvious a decade ago either.

I've seen some more "checkbox engineering" that claims to add reuse to next generation rockets (doesn't Boeing and/or ULA have a plan involving snatching parachuting engines?), but I still don't expect government and/or military rockets to be cheaper than expendable Spacex rockets with or without reuse. Reuse is simply one technique to reducing costs. It is a blindingly obvious one, but it isn't some sort of magic trick that makes space travel suddenly cheap: the Shuttle proved that.

BFR (and/or New Glen or maybe New Armstrong) just might. You certainly need a lot more mass than the Shuttle, you have to take advantage of technologies simply not available in the 1970s when it was designed (they weren't going to hoverslam F1 engines, for example), and do so in ways that don't involve making Congressional budgets happy (I've seen the US Navy happy with a 10x markup on ordinary computer products, mostly because of all the other requirements it takes to fit them on board ship). Time passes and technology improves. To do all of the Shuttle jobs, you'll need either a lot more mass or a Shuttle. But I won't say SLS is doing that job (they are making each flight *more* expensive).

Anybody know what the Einstein wing looked like? https://wrightstories.com/einsteins-wing-flops/ Back when I believed the "classic" "wings work because aerofoils produce lift" I assumed that something like a Concorde or Delta-wing would be ideal, with long thin wings to maximize the area pushed on and minimize cross-sectional area causing drag. But for whatever reason, long thin wings produce more lift to drag than anything else.

It's been three days and nobody has mentioned Dr. Kenneth H. Cooper? Seriously, google him for more than you ever want to know about "fat guys as [military] pilots". Sometime in the 1960s, the US Air Force was having issues with pilots dying thanks to heart attacks in flight. Colonel (he retired at that rank, but may have been promoted by then) was trying to find the answer and eventually determined the link between exersize (and lack thereof) and cardiovascular fitness. The pilot's presumably qualified in physical strength qualifications (especially needed at high-G maneuvers, and presumably fitting the "strong and manly mentality" of the 1960s Air Force), but were lacking in endurance conditioning. Cooper eventually could measure a pilot's danger of an inflight heart attack by having him run for 12 solid minutes (I thought the old test was longer, but currently it appears to be 12). In 1968 Cooper published a book named "Aerobics" which explained the need for continuous exercise that raised the heart rate for 20+ minutes straight. In 1970 he retired from the Air Force to push his new theory on exersize. Last I heard he was also (as a doctor) trying to keep Jim Fixx's offspring alive (not so sure, usually the story goes "his son", but wiki shows four children. This might be one for Snopes).

Classes are wide open? I had a whole long reply how it should have been possible (within *strong* boundaries, and extremely expensive), but that assumed some sort of API between KSP and mods. If the modders can meddle with the classes directly that is clearly impossible. And of course trying to change this would fundamentally break *every* mod in a way that would require a near-total re-write. Linux has a specific API and most of Linus's famous salty responses were from those who dared break the existing [external] API. Change an internal hook, or expected binary interface? No problem. The catch is that what the KSP modders are doing is essentially the "internal API" and worse. And of course, even if you wrote your Linux program to the unchanging API, you still have to check regularly to see if KDE/Gnome or (gods help you) SystemD didn't break your program. You might as well ask them to not have bugs. The only way that appear possible is to have limited features, *NEVER ADD FEATURES*, and spend years (after deployment) fixing those bugs. I've heard that Knuth thinks he's fixed his last TeX bug, but that may be the only program sufficiently well written (and long lived) to become "bug free". Don't hold your breath for another one to come along (although things like jet-engine control software might also qualify. Don't ask how picky the FAA is in how software is written). For something that organically grew (and lives on top of Unity), that type of thing is strictly impossible.

The other issue is the accelerometer (or whatever you are using to determine landing). You probably also need some sort of laser/radar distance measurement to the ground. Depending on the TWR of the rocket, these will likely have some hefty speed/latency issues: try to make sure that I2C and/or SPI is good enough for both of these before making your final selection (it might be worth it to get a ardino or raspberry pi that includes an accelerometer on some sort of fast internal bus). Looking at the ATTiny 8 pin chip, it looks like pins 2&3 are tied to the crystal/ceramic resonator. That leaves one set of x-directional fins, one set of y directional fins, and one input pin (which might be an I2C bus to both the accelerometer and rangefinder, that just sounds too slow for a hoverslam). I'd recommend at least stretching it out to a 16 bit package to use the included extra two ports for something. Once the physics simulation is done in python (remember the point of the thread?), you should know just how much latency you can eat on your accelerometer and range finder. That will likely drive the selection of those parts, an in turn find a microcontroller than can interface with them (to a sufficiently low latency). I'd expect that a ATTiny can react faster than an actuator can move, but it needs the input signals fast enough as well.

I suspect that the actuators (or whatever actually moves the fins) and the interface it needs will determine what computer it needs. Hobbyist computers may seem low-volume, but nothing compared to computer-controlled model rocket fins. Presumably the thing will be based on RC-aircraft parts, and check there before solidifying the rest of the electronics.

It might have 15 times the Isp, but nowhere near 1/15th the thrust. Pulsing the coolant through an open loop system appears to work well enough. Expect any good sized spacecraft to already have a closed loop coolant system (like the ISS's that I used as the example for closed loop cooling), adding something like a nuclear plant on board will likely require increasing the power of such a thing if only thanks to heat migrating from the engine.

Note this is only true for LEO (which was most of the launches OP asked about). geosynchronous orbits definitely require a "coast" then re-burn, and a lot of the appeal (to customers) of the falcon heavy was the ability to re-light the engines for geosynchronous circularization. Geostationary orbits are even more complicated, as they typically do an inclination change beyond GTI and then require at least one more burn to get into position (ESA can launch from the Equator and ignore this).

My understanding is that the EPR paradox has been consistently shown "transmit information" no faster than light speed. While some bit of the wavefront of a "signal" can creep past c, not enough to actually use as information does. The other bit is that if you look at what is needed for "multiworlds", you have the same difficulty in that the 'tears' where worlds divide move faster than c (this is mostly contemplating it on my own, while others insisted it satisfied both relativity and quantum issues. Not something I heard by people who've studied both more than an engineer).

Note: if you are doing something covered by Orbiter, Orbiter will be a better simulation. I'd also recommend that KSP (with RSS/RO) would be a great quick and dirty means of doing a sanity check after coming up with "correct" thrust, mass, and delta-v values on a spreadsheet. This is especially good if you are limited to using existing engines (which would exist in RSS/RO). Things don't always work in KSP straight off the spreadsheet. Real rocket science will be even worse straight off the spreadsheet (regardless how accurate you might have made the spreadsheet). And it is absolutely ideal for visualization in your presentation. Just include all the calculations and don't rely on KSP (especially KSP's 32 bit float's done in Unity's physics simulations). [the rest is on the rocket] I'd think that a Stratolaunch should exist. You might simply cheat and hack the thrust/lift of a B-52/L1011 (both have launched Pegasus, so at least one should have a file around somewhere), at least until everything is finished. I'd avoid tying a launch to Stratolaunch (mostly IRL, an academic project is fine). The biggest issue used to be that your rocket is essentially at a dead end because your mass is defined by the plane itself and there is no where to grow. Well that *was* the biggest issue, the new biggest issue is that without Paul Allen, who's going to keep paying to make it fly? Even Orbital (who was founded on such an approach) hasn't been all that interested in supplying a rocket for Stratolaunch.

Edited rest mass to relativistic mass.

I'm confused. KSP uses fairly basic calculations to determine each of these burns. Unfortunately, to keep things simple they are based on some "delta* function thrust" which has infinite thrust for an infinitely short period of time (that integrates to some unit delta-v/kg) and you have to burn some factor of these delta-thrusts. I'd hate to try to calculate the error involved thanks to realistic thrust. Note that if you can use a Mangalyaan manuever (typically called "pe kicking" in KSP) you can get arbitrarily close to minimally wasted delta-v, assuming you can keep your pulses arbitrarily short. Unfortunately this doesn't help at all for kicks above escape velocity (and obviously the original Mangalyaan plan had to make the last kick hard enough to go from a high Earth orbit to Mars Transfer). Note that any additional mass required for the last delta-v burn will propagate back through all earlier burns requiring more delta-v and more mass. Expect some really ugly equations (if they are even linear). This is the type of thing that really gets done on a computer simulation. * sorry, but the "delta function" has nothing to do with "delta-v" but was created by Paul Dirac to simply some things. It is also critical in transformations such as Fourier and Laplace transformations. It is a function that is zero everywhere but 0, infinite at 1, and integrates to 1 for any integral containing 0.