Zeiss Ikon

Right click on the small picture on the page you linked, then "copy link location" and paste the result in your message. You'll get this: Nice spaceplane, BTW. does it SSTO, or ride up on something else?

Of course, I meant 1.8.x -- it'll be a while before 1.18 appears (if development even continues at the current pace once KSP2 drops).

I haven't played a science save since I started my first career, back in 1.3.1. Haven't gone back to my old stock-plus-Better Burn Time career (which had been upgraded to 1.4.1, then 1.6.1) since I installed Realism Overhaul on 1.3.1. Played through the sounding rocket era at least six times, maybe eight, on "hard" mode, going broke before getting basic satellites into LEO. Installed a new RO in 1.6.1, playing on "normal" with a couple setting changes (that's now recommended for "inexperienced" players) and have gone through the sounding rocket era a couple more times, but it just wasn't the same without Principia -- but now I got the library upgrade and can use Principia again; my sun synchronous orbit will really BE sun-synchronous, so I'm ready to try to get at least to crewed Lunar missions and probes to Mars and Venus.

Electric propellers and ducted fans (both stock in 1.18.x and/or Breaking Ground expansion) work anywhere there's enough air to bother. Eve. Duna. Laythe. And certainly Jool. You'd probably need an RTG to provide power for the electric motors, since Jool is a long way from the sun and bringing LF/O for fuel cells seems less efficient. I agree with @linuxgurugamer that the same EC rate would let you lift more mass with wings than with thrust hover like a drone. You can also build stock helicopters without all the gyrations, BTW, their power efficiency ought to be somewhere between a quadcopter and a fixed wing airplane.

A couple weeks of digging around when I had time to do so, and I found this ppa host that has a backport of llvm-toolchain-8 for Ubuntu 16.04; I installed the needed libraries (libc++-8-dev and libc++abi-8-dev) from that ppa, and (so far) my Ubuntu still works (it should continue, since these are rebuilt under 16.04), and Principia for November at least doesn't crash on starting the RO install (nothing in orbit in the existing save that I opened). I couldn't find a link for the binary for Frechet (also don't have the correct French accents on my keyboard), so I wound up with something with a Greek-looking name, dated November 23. Since Frechet was only a couple hours old on GitHub, I presume the binary and updated Readme to link to it will be along later.

Even if the working CO2 scrubbers (which require power) hadn't been jettisoned with the LEM, there wasn't enough oxygen storage in the CM to last another several days if reentry went too shallow and they wound up back out in orbit. Not to mention insufficient battery power to prevent hypothermia, keep the scrubbers warm enough to operate, etc. If the CM had in fact been too shallow and wound up leaving the atmosphere, even a few hours after dumping both the LEM and SM would have meant a dead crew -- or just possibly (if the apogee was low enough and the period short enough and the crew drew straws or had two volunteers) a single hypothermic survivor who was no longer functional enough to fly the reentry a second time, even if it was possible to do so in a CM with dead batteries (unlikely in the extreme; I recall the attitude system being electrically controlled). No question, if they'd failed to fully deorbit and gone back out, they'd have died, just more slowly than if they'd gone too deep and got cooked (or died from G overload with a prolonged 10G from being too low, too fast).

Once you're beyond the sounding rocket level, hot staging benefits mainly if you have to stage at relatively low altitude, when depending on gimballed engines for attitude control. If you're flying at Mach 1 or faster, there's a lot of dynamic pressure on the nose of your rocket, and if you won't have large (heavy) fins on the second stage (and even larger, heavier ones on the booster to keep the rocket from swapping ends almost immediately after launch), that stage is going to tend to tumble between MECO and second stage start, even if you have ullage rockets powerful enough to overcome air drag and get a reliable start. By hot staging, you avoid having a gap of a few seconds in your vectored thrust. American rockets, historically, handled this by not staging in thick air -- a modern example is the Falcon 9, which stages above 100 km, where there isn't enough air to matter. Early Soviet launchers, by contrast, had shorter burning engines. One of their methods was to ground-start a core with a longer tank and a set of side boosters with shorter tanks, and stage away the side boosters while allowing the core to burn longer, but even then they still used hot staging, likely because ullage rockets added complexity and reduced reliability (or possibly because they simply didn't have suitable small solid propellant engines, though engines from air-to-ground or air-to-air missiles are very suitable for this).

(1.8.1, Breaking Ground, Making History, stock) I am saddened to report that, while attempting Matski's rescue in a fairly inclined orbit beyond the Mun, Jeb managed to strand himself, Bill, and Matski (again), despite leaving LKO with over 2000 m/s of dV in an upgraded Rescue series craft. I blame negligent piloting, using excessive velocity performing the rendezvous with Matski's craft (another Onion without engines or tanks -- how does a craft like that get that far out?), and excessive dependence on a Mun assist that turned out to provide less assistance than expected. I had a quick save with Val on the launch pad before Gradard's rescue launch, so I've reflown that mission (with frequent quick saves) and am in process of adding still more dV to Jeb's craft to ensure he'll have, on LKO, the 900 or so m/s to reach the required orbit, 200+ to circularize, 300+ to change plane, then some to rendezvous -- and still have 400 or so to drop periapse well into the atmosphere for the return. I think 2500 m/s after LKO circularize ought to do -- but then I have to figure how to get that large a vessel into orbit with only 1.25m parts (and no crossfeed available on radial decouplers -- technology not unlocked yet). It's likely to involve Moar Boosters...

Well, not today, but last night and the night before (because of limited play time). (1.8.1, Making History, Breaking Ground, stock) I took my first couple rescue contracts (actually had one offered before Jeb's Mun flyby, but without mission planning there was no chance of getting a rendezvous). Two stranded Kerbals in orbit. Should have gone to Tracking before I clicked; Gradard was in LEO, in an Onion with no engines (and apparently unaware of the "get out and push" method of deorbiting); Val easily rendezvoused, parked her craft a mere 10 m from Gradard's, and Gradard made a trivial EVA. Turns out the other rescuee was in an orbit much like the one Jeb would have had if he'd tried to make his return burn while still in the Mun's SOI without nodes -- that is, pretty inclined, and a bit beyond the Mun's orbit. Val's rescue craft lacked the dV to even make an attempt that far out, so Matski will have to wait another day while the guys in the VAB build something with a bit more oomph. Val, unlike Jeb, had the sense not to even try, and carefully deorbited even with 600+ m/s still in her service stage (she'd have needed close to 1000 to have any chance of getting Matski). I was a little concerned whether the Pea/Mk.1 pod stack would be stable in the correct direction, and decelerate enough, high enough, for parachutes to be effective, but with a full size heat shield, it was rock solid through reentry. And despite having no control at all after entering atmosphere (the Mk. 1 can be flown, just a little, but not the Pea) the returning pair landed less than 35 km from the Space Center. Now someone has to go get Matski. Hopefully without getting them both stranded out there.

Modern American ICBM and SLBM are solid propellant. The Titan family was the last liquid fuel ICBM in the US inventory, and it's been out of that service since the 1980s. There were never liquid fuel SLBM in US service.

And you're pretty much correct. During most of the Apollo 13 flight, one astronaut had to remain in the CM, because there wasn't room for all three in the LM. The LM, however, had working air circulation and (after they adapted the lithium carbonate cartridges from the CM) scrubbers, while the CM did not, while it was powered down. @Robonoise, if you want to make it a little more challenging, you could require that the CSM batteries and/or fuel cells be locked out after the explosion, to be unlocked only during preparation for reentry. For extra credits, the challenge could be done in Realism Overhaul...

Yesterday, I started a new career in 1.8.1, Making History, Breaking Ground. Also yesterday, I made my first Mun flyby (took about six launches to get the science). I've been playing nothing but Realism Overhaul for more than a year, and I'd been meaning to pop the funds for Breaking Ground, so I downloaded 1.8.1, a compatible copy of Making History (which I bought when it came out), bought and downloaded Breaking Ground, and set it all up. Started with the common first launches, Mk. 1 pod, Flea booster, Mk. 16 parachute, and three Basic Fins, launch pad EVA reports, etc. Worked a couple hardware test contracts. Finally, I was pretty sure I had the technology to go for orbit (well, actually, I launched Val, and reverted the launch to accept the contract after verifying I had the dV and then some). I'd forgotten how little rocket it takes to get to orbit on Kerbin (this thing wouldn't get to half of orbital velocity on Earth). In fact, this Vector A Terrier was able to make a 77x93 km orbit with a whisper of fuel left in the second stage, without even igniting the Terrier. After a little testing and some science, Val stayed up for two orbits, then returned to Kerbin (something about a tickertape parade date). Of course, we all play KSP, and we know what this means: stretch the third stage tank and go for the Mun! Getting to the Mun without manuever planning is a little, um, uncertain, but we can trust Jeb to get it done. The extra fuel weight meant the Terrier had to burn a bit to make LKO, then there's the 800 m/s or so to get from LKO to the Mun -- that left Jeb with 139 m/s at his Munar periapsis of 718 km. He couldn't confidently make his return burn in the Mun's SOI (no nodes, no orbit projections), so he waited another orbit, past his perikerb of 1350+ km and back to apokerb of 12000+, where orbital velocity was just over 300 m/s and just over 120 m/s was required to lower his perikerb down to about 42 km. Sorry, no shots of the aerobrake pass, but nothing burned off the pod, and just for flying by the Mun, Jeb brought back 89 science, unlocking the rest of the 45 point tier, as well as bringing in enough in contract payouts and "World's First" donations to upgrade the Tracking Center, making Jeb's the last mission in this save to be undertaken without maneuver nodes.

@kerbiloid Pretty sure Walter Cronkite wasn't a time traveler. If he were, he might have managed to convince von Braun to quit smoking, or done so himself. And that guy in the photo doesn't actually have a cell phone, even though it might look that way. What he has is probably a tiny one-tube radio receiver. Miniature tubes were available before WWII, if you had some money, and were built with two or occasionally even three "tubes" inside a single envelope -- that would give you enough electronics to build a superheterodyne AM receiver that would fit in a shirt pocket (pack of cigarettes, pack or cards size, running on an external miniature 22 V B battery; a couple D cells for the filament would give several hours of operation with weeks of life on the B battery).

Still, I, too, remember Cronkite talking about the too-shallow reentry as if it was a one-way trip to Earth escape. Fifty years later, it occurs to me that Walter was a reporter, and probably knew next to nothing about physics and orbital mechanics...

Did I mention Linux and Ubuntu aren't themselves a hobby for me, never mind a job? I have no idea what llvm and debootstrap are or are good for. I use Linux mainly because it isn't Microsoft or Apple...

Seems as if even upgrading to 18.04 wouldn't help me; I searched for libc++-8-dev and found it only in Ubuntu 19.04. I am NOT going to jump on the "upgrade every six months" train. Sad that the need for "useful features" pushes the entire mod out of the "Linux is just an OS, not a hobby in itself" world. Maybe, instead of upgrading Ubuntu, I need to look at Debian based rolling distros...

Thanks. I was afraid of that. Clearly there's a strong bias in the Linux community in favor of those who upgrade everything at the earliest opportunity, vs. those who ride the old as long as possible to avoid having to spend their work/play time fighting bugs and learning a new system only to have it change again (figuratively) the next week. If you jumped off 16.04 in mid-2017, it had to be to 16.10, 17.04, or pre-release builds of 17.10, and as you say, it's anyone's guess whether stuff made to run on that would work on 16.04. I'll grab the binary you pointed to and see if it'll work. Thanks for the help! EDIT: Followup, not surprisingly, Principia Euclid (seemingly built under Ubuntu 16.10 or 17.04) caused my 1.6.1 RSS/RO/RP-1 game install to fail to start on Ubuntu 16.04. The library versions cited above are those for 19.04. I'd suggest that at the least, it might be more user friendly to keep support for LTS versions, at least until the next LTS comes out. At present, it appears that one must keep up to the latest non-LTS releases of Ubuntu in order to keep the most current Principia as recommended by the devs. Worth noting that the game itself seems to work in all supported versions of Ubuntu -- evidenced by the fact it works fine in 16.04, which is the oldest currently supported version. FURTHER EDIT: If I had the faintest idea how to build a complex program like this, I'd try building it myself to see if that fixes the version dependency -- but I don't know in detail how to do that.

I'm a KSP Linux player, currently using Ubuntu 16.04. I recently installed RSS/RO for KSP 1.6.1 (previously I'd been playing RSS/RO 1.3.1 for several months without ever updating my Principia, then didn't play KSP for most of a year). I found I couldn't use Principia because it needs library versions that are only available in Ubuntu 18.04 and newer. Because I'm trying to hold out for Ubuntu 20.04 before I "upgrade" (because, with the amount of "tainted" software I run, it's "install clean, taking a whole weekend for each machine" instead of just running an upgrader), I seem to have two options. One, I can try to find a way to upgrade just those libraries, but that's likely to break major things in my Ubuntu and render my install non-functional (requiring me, at a minimum, to restore the old versions via command line, potentially via a Live thumb drive). Two, I can try to install an older version of Principia -- but I don't see that older binaries are available. I'm looking for the oldest version that supports 1.6.1, in the hope that it won't require libraries newer than my 16.04 Ubuntu. Three, if I can install the necessary libraries for only Principia, I'll be good to go for another several months, at least. The libraries in question are libc++ and libc++abi. I can download just the binaries for those libraries -- would Principia find them successfully if I place them inside the Principia folder?

I present, I'm using 1.6.1 -- but that's with 74 mods installed for Realism Overhaul. As @VoidSquid noted, you'll probably want to check the supported versions for the mods you need/want. I don't have all the mods you want installed (i don't recognize the ASET one), but parts packs and procedural parts that support (some) sounding rockets are part of a 1.6.1 RO install, as are Deadly Reentry and RSSVE (the Real Solar System version of EVE). There may be other parts packs that would support more modern solid fuel sounding rockets. The Black Brant family are all solids, for instance, and there are/were a bunch of other sounding rockets with solid fuel motors -- RP-1 starts you with the WAC Corporal specifically because it was liquid fueled, one of the first high-flying liquid fueled rockets, and direct ancestor to engines still in use today (AJ10 series were developed from the WAC Corporal engine).

Milestones. "First" anything pays better than any of those routine contracts. "First probe flyby of the Mun" or "First crewed flyby of Duna" etc. These "first" events, if you load your craft right, also tend to generate big bunches of science, which advances your careeer into improved tech that gives you access to even further milestones. More generally, with the skills and experience you have now, you ought to be able to estimate fairly well what a vessel will cost to accomplish a given contract, so don't take contracts that won't produce significant profit -- or set things up to complete multiple contracts on a single launch. Got four tourist on one contract who want to fly by the Mun, one of them wants to land, and three on another who want to land on the Mun and fly by Minmus? Launch one vessel that can both fly by Minmus and land on the Mun, and carry seven passengers plus crew, plus (assuming there are still biomes you haven't tapped out for science) science instruments. Considering that a gravity assist from Minmus to the Mun is almost free compared to just going to Minmus, the only upgrade you need compared to a minimum craft to do the Minmus flyby is enough dV to land on the Mun and get back to Munar orbit, around 1100+ m/s, plus the pittance (a couple hundred?) you'll need to capture into Mun orbit after the transfer from Minmus.

Kind of an ambiguous question. I spend more total time on rockets, but I don't build or fly many aircraft. I can build a rocket, pod to clamps, in a half hour, unless I'm having to scrape for that last m/s, but I usually need several hours to get an airplane that will fly stably. Of course, this is with FAR in RO...

The kerfluffle over the EM drive was based on claims that it had more thrust than could be accounted for by its radiation, i.e. It was violating conservation laws. That now appears not to be the case; instead, the inventors fooled themselves by failing to eliminate confounding factors in their tests. It's emission, BTW, is heat/IR, not microwaves, which are efficiently trapped by the truncated come enclosure.

I think you forgot to divide by the square of the speed of light, a factor of about 9e16...

Yes. Damned little, though. You can calculate the thrust due to light by using the mass equivalent of the emitted energy and lightspeed as your exhaust velocity. End result is you get a non-zero thrust from any light source (if it's directional), but it's very, very small.

That would explain most of what you're seeing -- no orbit ellipse for Crisdon, inability to get a target lock. "Debris" might be because the game decided (s)he was below the surface and crashed, but won't actually show the craft as destroyed until you're within physics range. The "last seen on" and size class, however, are typical of an asteroid. I supposed the game getting confused with Crisdon being inside the Moon might do something weird like that, but I think it's very unlikely you'll be able to make this rescue. Mine all you like, you can't dig actual holes in the Moon (or the Mun).