wumpus

The "official" launch window for Mars is more like March-May, I'm curious how close NASA is willing to let them get a "dirty" rocket near Mars (although a *tiny* bit of aerobraking would be ideal for making sure Teslas never rain down on Earth).

I suppose sooner or later I need to break down and buy a gamepad for docking. Every time I dock I realize that I need two sets of inputs (rotate and translate) and the keyboard is klunky. Has anybody done that? Can you put the gamepad down when not docking without random crashes (when a gamepad button is accidentally hit)?

You might want to consider a hollow planet (pretty much any idea has to be artificial and has significant issues. Hollow planets would require less "tech levels" than most others. I'm surprised that I haven't seen an analysis of Kerbal's atmosphere in the years I've been on this forum (maybe I just missed it). I have no idea how much oxygen and nitrogen Earth loses each million years or so, but would have thought it was significant. I guess it isn't: while there is plenty of oxygen locked up in the ocean and rocks, I'm less sure where nitrogen could be hiding. I suspect Kerbal has roughly the same oxygen partial pressure (slowly being grabbed from sources) and no significant nitrogen.

Go back and read the directions to find out you need to press the start key. Or possibly include a capsule/probecore to make it work at all (this was well before .25 and I was following campaigns that started unamanned). For whatever reason I couldn't launch the first craft, second was a go. Current career mode starts go into space via explosive staging. According to KE, orbit is nogo thanks to the maximum delta-v of a stack of mass-limited boosters.

There have been a few comments from users who have trouble with the graphics issues (presumably laptops with integrated GPUs). Another issue is building the game on Unity. Squad wasn't willing to ditch the physics calculations of unity (which did all the calculations in single point on CPUs easily capable of doing double precision just as fast [single point floats were the source of the original Kraken and still manifest themselves in wobbly orbits]. I'm assuming that Squad is doubly disinterested in ditching Unity for better graphics. If you want prettier graphics, keep modding till it crashes! The problems I have with KSP tend to be in the VAB-GUI and weird bugs (often not seen in 1.2) that seem to delete things (I'm shocked silly you still need a mod to fix issues with Jeb either stowing away or refusing to fly if you put him in the seat). More intractable issues are that career mode really isn't well integrated (the original vision was obviously a sandbox: career is ok, but obviously tacked on). I'm curious to see what the DLC will look like (it looks like I bought the game a month or two late, still no complaints about cost or paying for the DLC). As far as comparing to a "AAA" game, I'd compare it to a Bethesda "AAA+" Elder Scrolls game (Oblvion, Skyrim, etc). Wide open, more gameplay than you can play in years, desperately needs a ton of mods (nearly all of which are available) and quite buggy. So even "AAA" games are often like KSP (and I'll buy Elder Scroll game with or without a review, although often months after release to avoid gamebreaking bugs).

Seeing how it was a suborbital shot, isn't the main source of lateral velocity drift while parachutes are deployed?

[tl;dr] download the demo. Spend a few hours on it and decide if you think $40 (or sale price) is worth unlocking the limitations. Unfortunately, the early access system that paid for game development paid for features first and bug fixes eightynineth. I had great hopes when harvester announced he was re-doing the GUI, only to find out that he only touched the in-flight GUI (which is wonderfully better) instead of the rocket design GUI (which is the source of my real frustrations). One thing that is ignored about questioning the cost of KSP is that they (unlike virtually all games shipped since 2007 or so) include a demo. While the demo isn't available right now from either Squad or Steam, I think there are links in this forum to at least one of these (Squad's website had one based on 0.18, Steam's was based on 1.0.0). While we have been arguing that KSP might be "worth" vastly more than $40 (although I'd expect it on sale off and on, try putting it on a Steam wish list for notifications), this is likely because all of us have sunk significant amounts of time into the game. If you want to know if it is worth it, download the demo and put in several hours and see if you want to spend $40 worth of time expanding beyond the demo's limitations. I've spend >$300 ( in small chunks ) on at least one MMO without regret, and might be half that on another. The reason I spent this was I had tried the game and was hitting various limits and needed the expansions/upgrades. I doubt I'd pay that site unseen (and started "late" on it when I *could* try before I bought). I'd recommend trying the demo before plunking down *whatever* you think is "extremely expensive" (I'm sure I've seen a $25 sale this year). https://forum.kerbalspaceprogram.com/index.php?/topic/131906-the-earliest-versions-of-kerbal-space-program/ [contains links to KSP version 13.3 and earlier. That might be a little too primitive (I've never tried it)]. Notes in case you try the demos. As mentioned, one is based on .18, that is "classic KSP". The souposphere is in full force and aerodynamic stability isn't much of an issue ("pancake designs" were popular). 1.0.0 is probably harder and more poorly balanced (things weren't really fixed until 1.0.5), but nearly all of your hard earned lessons will go straight to 1.3.x. This isn't quite true with learning on .18, you will have to relearn nearly the entire game (just like the rest of us did between .25->1.0). Supposedly there is a demo based on 1.3 in the works, but it seems to have a terribly low priority (1.3 has been out for months, and I think the demo has been under maintanence for a year).

Powered swingby burn (H2/O2). That looks like hydrolox and not peroxide to me. I don't think storing hydrogen for 8 months was possible in 1960s/early 70s tech. Maybe with "space race funding" still in place they could have managed it, but the one project that requires similar tech (James Webb telescope) seems infinitely delayed. I wonder how big the 6-9 month habitat is. Skylab was the size of the TLI fuel tank (I think it *was* a retrofitted tank and definitely fit in its place on a Saturn V) which would be my go-to habitat (presumably most of the engineering was already done for Skylab). That doesn't leave much room on the other 2.

Note that on planets with an atmosphere, you wind up optimizing for a lot of variables. An ideal path should only burn along prograde, any used to turn the rocket are considered "cosine losses" (your loss is proportional to the cosine of the angle between your thrust vector and prograde). I'd call what you are asking for "hypotenuse losses". An ideal burn would calculate the vertical delta-v and horizontal delta-v, add them up in right angles and then burn along the hypotenuse. Of course in worlds with an atmosphere, you want to minimize aero losses so you start by heading straight up. Presumably NASA computers work out the amount of aero loss and "hypotenuse" loss and work out a trajectory that minimizes both (actually I'm sure they do a single burn to minimize the thrust needed from the second stage).

Gravity falls off faster on Kerbin (73% at 100km) than Earth (89% at 400km), but I suspect that Kerbal spacecrafts' lousy mass ratios (compared to real life) makes that a pretty moot point (assuming that nearly all the gravity losses occur in the first stage).

Is the argument against 0.1c in an [H-bomb based] Orion that you would need 100,000+ tons of dueterium (assembled into H-bombs, natch)? Because that's one means of harnessing fusion that is ready to go (assuming are either willing to build and take off from Antarctica or build something carrier-sized in space). If the rocket equation starts to creep up on you, that will be a problem with Orions, as I expect the fuel gets pretty expensive. It will certainly do the "Mars in 39 days" without issue. Just don't try to fight the rocket equation.

I would have to point out that I found the rendezvous part more difficult that pure docking (at least once you get the hang of RCS). In career mode kerbal rescue missions give great practice in rendezvous (you can't really dock, but getting as close as possible helps to find the rescue ship once you've taken control of the "lost" kerbal. - check for an empty seat before takeoff. Jeb loves to grab the seat whether or not he was placed there. If you even touch the capsule after taking him out he might sneak back in (especially after loading a save). There is at least one mod out there to prevent this.

And astronauts had to be under 6' (~180cm?) to even apply for the astronaut program.

"Several passes" works on Duna/Eve, but going much further afield pretty much means you need as much delta-v going beyond Kerbin's SOI as you need to get to the edge. Still, breaking it into 2 cuts the thrust needed in half (or your lack of Obereth gains in half). I'd also look into Juno slingshots (to anywhere past Duna/Eve). Of course, typically what you really need is an alignment change, so in that case it might be better to kick off Duna, Eve, or any you can reach while it intersects with the plane you need.

Getting rid of the math will be a bit of a problem, but if they don't have the background to understand ln(massfull/massdry) you won't have the time to build up to that. Obviously you need to explain orbits, although centripital forces should be easy for anyone (all they need to understand that gravity goes on forever, and is still strong out by the ISS). Obviously conic sections are relatively easy if you have a cone available for slicing (don't most schools have pre-sliced cones?), although the why pretty much requires multi-variable calculus. Since KSP works on Kepler's system (not really Newton's), that makes it easier to go with Kepler's non-calculus orbital mechanics (he has a nifty speed/area law which should be understandable with little math). Getting the rocket equation without math will be a bit of a problem, but it should be clear that to get "more dakka" (delta-v) you need to add more fuel, and more fuel to push the fuel you added, and so on. Who knows, maybe after having the tyranny of the rocket equation shoved into them by KSP, they will get logarithms. I'm not sure KSP EDU sells well enough for people to know specific mission issues. Since this showed up on a non-EDU forum, you might get at least answers from "regular" KSP (like this one).

POTUS: only motivation of POTUS would be to attack the Senate. Might be possible, especially if Roy loses. VP: VP's power is traditionally limited to making speeches unless deliberately handed power by POTUS (i.e. any VP action is a POTUS action). Should Pence have executive powers (for whatever reason), killing SLS could be useful to be seen as "getting something done" (sure, the current POTUS could do that, but it sounds more like a "first 100 days" thing. So maybe POTUS 2020 as well). Bridenstine: SLS is something like 1/3 of NASA's budget and it isn't remotely clear that they can simply move the money (it is essentially is earmarked for SLS). While some Presidential nominations are specifically hired to kill the agency they were hired to "lead", I don't think (and certainly hope not) that Bridenstine was one. You simply don't gut that much of your agencies' funding. Obviously the Senate can kill the Senate Launch System (presumably so could the House, but I can't remember the two houses fighting each other and that might "not be done"). Sorry about the politics (I try to keep any mention of politics neutral as far as "what should be done" and more to stick to "who can do x" and "who certainly won't do y". Since launching rockets into space is primarily done by large governments, completely avoiding politics is impossible for all but Blue Origin launches (Even Bezos builds in Alabama for political reasons)).

That's not too bad. I can't really translate UK educational levels, but I remember writing down the derivation for *circular* orbits during a second year university physics exam (had to be done in less than 5-10 minutes just for that question). This can be done with polar coordinates and doesn't require calculus (and thus doesn't explain ellipses nor the area law, but handles the degenerate case of ellipse==circle well). [this may have been deriving gravitation from circular motion, it has been a long time]. Unfortunately polar coordinates are unlikely to remain your friends with ellipses, although it appears that again solving for the degenerate case of ellipse==line works well here, and then showing that orbiting in two orthogonal "lines" forms an ellipse is the method used above (maybe not explicitly, but certainly that is what x and y are doing). The spherical coordinates might be a bit of an issue. Working from Keplar we can show that everything stays on a plane, and I can see how you can show that Kepler's orbits are stable, but I'd hate to show that every [large/small] body will follow conic sections (and remain on a single plane).

4865 for grinding Minmus (not sure that is a record [I've done similar in other career modes], but I did it Monday and took a screenshot so I have the exact value). Of course, I also stored the data in triplicate so Minmus science bases can process the data well past the tech tree... I'm pretty annoyed with the science grind ("for science" only helped so much in storing multiple data).

A thermocouple is a pair (or more) of twisted wires of two different metals. Of all the bits of a 100year+ spacecraft, that would have to be the easiest to design (of course, I'd look into peltier devices for better efficiency, but don't expect them to last all that long). The computer electronics I don't have much hope surviving more than a century. I'd assume that any such device (Uranium powered thermal generator) would involve some type of criticality. The obvious choice is for a capture burn decades or centuries after the initial burn, and to send messages back to Earth when you got there. Thus it wouldn't be a RTG but some sort of ultra-simplified reactor (the original "Chicago Pile" had no cooling and produced nearly no heating/power). The reason for going with the reactor is to not require an isotope that lasts the entire journey. A better solution would be to use Americanium241 this is a possible replacement to Pu238 for those (EU and others who simply can't get the stuff, also Pu tends to alarm the general public). It only puts out 1/4 the power per gram, but a 432 year half life makes it almost certain to outlast any other component on the spacecraft (I think we will lose contact with Voyager due to running out of propellant to keep the antenna aligned, it should be a bit over 3/4 power in the RTG).

So instead of being "20 years from now" fusion will be require a steadily increasing size until it exceeds Earth?

Presumably a low power beacon is all that is needed (I'd have more than three around the pad for better accuracy) as it will first head back to just offshore in case of failure and they can make contact for the final correction (I'm guessing there is too much plasma during the burn to offshore).

Is there a heat issue? The only thing I can think of is something using up too much CPU time (mining virus, try running "top" in a terminal) or a clogged fan. A clogged fan is a more likely bet as it wouldn't show up until the CPU is working hard enough to get hot, then the CPU throttles itself down to less powerful than your old CPU. You could try blasting the fan ports with compressed air to clear out the dust. And of course, try checking your other processes while running KSP to make sure nothing is using significant amounts of CPU time. An i7 should be able to handle things (I don't think it is a GPU issue, but that is possible. But even an intel i7 GPU shouldn't be that bad).

My understanding was that the steam demo *was* the 1.0.0.xxx edition (you could still get the 0.18.3 from Squad while it was up). It is gone now (or at least I couldn't find it). I'd expect it there first when the demo is re-released. Each have their strengths and weaknesses, but only expect basic rocket design that works for 1.0.0 to work with 1.3 (and higher) full versions. The stability requirements are vastly different.

My name is wumpus and I overbuild. Last night I needed to scoop up two scientists (the training run was the big project of the night), so I grabbed an off the shelf "rescue rocket". Since I needed to rescue two I added a landercan. I, uh, had enough delta-v to rescue both of them (was running a little low on monopropellant just from the mk1 capsule) without adding any more fuel or boosters. Yes, my stock "rescue rocket" has enough fuel to handle twice the mass to LKO and rendezvous. [my "record" for overbuilding was probably a [sandbox] Duna mission where I didn't need *half* my delta-v. The thing had a NERV and tons of fuel. I may have needed the NERV for capture (but not Kerbin-Duna transfer) but KSP deleted it while orbiting Duna (possibly because it was between Duna's atmosphere level and Kerbin's?). I still managed to get home on the fuel in the lander. In my defense, I think I was running stock at the time thanks to an upgrade and my mod stack crashing the "new improved KSP".]

) deltav=Isp*ln(mfull/mdry) Fuel usage is *always* exponential for any amount of delta-v. It might be reasonable to cut it down, but you are adding it on top of 15km/s delta-v. Those extra few delta-v aren't cheap.