DDE

What I'm pondering is why there aren't that many solutions that push for mass flows sufficient for launch, by using lOx afterburners and hotter core designs (up to an including gas cores). Cooling isn't that of a problem; reaction mass is the coolant.

I've been toying with vertical SSTO rocketships over the last few days. In particular, I had quite high hopes for @Nertea's pebble bed lOx-augmented modded NTRs, however, they still turned out to be more mass than wallop at take-off. So I have this non-KSP question: why do vacuum-oriented chemical and nuclear rockets lose this much thrust ASL, and why then are nuclear lightbulbs frequently touted as the SSTO engine of choice in hard sci-fi?

Hm. Not nuclear. I suppose Heinlein would be slightly disapproving. I've been toying around with Nertea's hydrogen and nuclear motors for some extra Isp and hence better mass ratio; admittedly, the pebble beds I had high hopes for have thus far proven disappointingly weak. What's with the use of Mk 3 fuselages? Shouldn't you try to escalate to the 3.75 m tanks to cram more fuel into less craft length and less drag?

Jumping onto the xenon bandwagon, why doesn't the ISS use the hydrogen from electrolytic oxygen generators for some sort of electric propulsion?

Thanks to having completely lost sense of the days of the week, I'm going to try to turn your Sunday into a Monday with these. They're proof Jeb deserves that second qualification ribbon. Before the next major op, I may have to populate the KSC Mission Control rosters with mostly-generic Kerbals (Bobak, get out from under the table!). All four of them.

It's revenge for all the 'faux Cyrrilic' that gets thrown around.

So here I am taking a new ship for a spin. I try a targeted launch with MechJeb, it takes me within 2.7 km of an old 1.1.2 station that hasn't been given me crap yet; map says closest approach at 1.4 km. I timewarp to the sunlit side, and halfway through to the closest approach, I spot the station at 870 m. I dump the rest of the launcher, and fire up the Rendezvous Autopilot. The approach burn is executed flawlessly, but the final relative velocity kill burn doesn't happen; I try again, same thing. As I find out after turning the autopilot off, the controls, including throttle, RCS and orientation, freeze up within about 300 m of the station, and then upon reaching a certain distance. I took a look at the debug console, and there's a ton of errors. Possibly related to Log: https://1drv.ms/t/s!AmlSZuL0ax7C0BW8DlfPVp5D2WuB Mod list courtesy of AVC:

Chapter 13: Cueston, We’re About to Have Problems Gene straightened out his white waistcoat. Jeb looked back at the two dozen koffee pots; a strategic supply of near-lethal brew was absolutely necessary for a night launch. Suddenly something occurred to him. “We’re sending a fully female crew, aren't we?” Pilot Kathula Kerman, scientist Eilphie Kerman and engineer Zelmy Kerman were to take another Hermes-B for a trip to Minmus orbit. There was only one major difference beside the ejection burn length: the launch was timed and aimed for Minmus’s slightly inclined orbit. The blast-off went as usual. “FIDO, confirm trajectory,” Jeb asked, tensing up. Gene furrowed his brow. “Flight, orbit is inclined 7.5° relative to Min’s orbital plane. Requesting permission to schedule correction burn.” Somebody on the ship-to-ground circuit began screaming. Jeb sighed. “We have more than enough fuel in the Δv budget to cover this.” “Hermes, initiate TDE.” “CAPCOM, we have hard dock. Separating stage… Negative.” “Hermes, repeat trigger.” “CAPCOM, negative on the extraction.” “Bill, can you try and bypass the system?” “I can fire the guillotine from here, but they won’t be getting the separation motors.” “Collision hazard?” “It’s abysmal.” Jeb only slightly relaxed after injection and TDE. “Neither’s not the rookies’ fault,” Gene tried to reach him. “I still want Jenrick or whathisname in a Vector ASAP. Gus, how much time?” “Three hours, boss.” ---------- “Vector, stand by for blast-off in five, four, three, two, one, ignition!” “CAPCOM, this is a kick-cheeks ride!” ‘I’m beginning to like this guy already,’ Jeb mused. “Alright, Vector, you’re in a 250 km orbit two hundred klicks ahead of your rendezvous target. Your move.” There was only a brief pause. “That would require a boost to a seven-hundred-something apogee for an intercept in one orbit, right?” Jeb and Val exchanged a raised eyebrow look. “Booster, I need you to sequence an SM engine firing immediately after exhausting the Chelyabinsk. FIDO, please confirm burn direction.” “Vector, FIDO here, you’re bound for intercept in 63 minutes, closest approach to TARDIS at 1.4 km.” “I am definitely liking this rookie,” Jeb said out loud as Jenrick dropped into station and spun around for an approach burn. “Thanks, sir.” “CAPCOM, permission to bring her in?” “Dock that bird, Vector.” “Aye-aye.” “Vector to CAPCOM, hard dock achieved.” “Nice one, Vector, bring her home.” “Roger that.” “Flight, I’m plotting a precision entry burn in 4-30.” “Copy that, advising SAR teams,” Gene responded. “Don’t get cocky, kid!” Jeb added. “I’m afraid this hotshot’s overshooting,” Gene said, watching the meteor scream across the sky. “It’s still better than the North Pole,” Val muttered. ---------- “Alright, Hermes, I’ll be your EVA officer for today, Zelmy, please proceed with checklist 162. Kathula, man the LS controls…” “Alright, now close the hatch behind you,” Jeb said, grimacing from the engineer’s screeching. “Now, I want you to drift ahead of the bow, ‘bout fifty meters.” “Perfect, now could you move to a slightly trailing position?” “Excellent, I guess that concludes the qualification EVA.” “You’re now to get inside and continue drift to Minmus SOI.” ---------- The injection into Minmus orbit occurred with no incident. “Flight, proceeding with mission program, I’ve got Eilphie manning the electronics and Zelmy on the camera. That means I’m up for EVA, right?” “Affirmative, Hermes, I only need you to drift clear of the craft for a minute or so.” Kath carefully neutralized her relative speed and peered back at the ship. “Eil, anything?” she finally asked. “Nothing, this iceball isn’t registering on any of my gear. Not particularly surprized.” “Flight, can we take it into lower orbit?” Kath mused. “Negative, get back in the craft,” Gene responded. There was radio silence for a few minutes. “Hermes, this is CAPCOM, we’ve confirmed that a drop to 20 km involves no short-term hazard, please proceed.” “Eil, anything yet?” “Had some bizarre reading way to the south, must have been a glitch. Otherwise, iceball all along. Might get occasional cover from the planet’s magnetotail...” “We’re passing just above Pathfinder,” Kath interrupted. Eilphie sighed. “Flight, CAPCOM, FIDO, whoever, this is a bughunt, request permission to begin departure procedures…” Zelmy piped up. ---------- “Alright, anyone, any final thoughts, words, anything?” “C’mon, I want to get away from the whiff of plastic and burnt snacks already.” Roszie locked the station’s hatch. “Alright, CAPCOM, this is… still Athens, proceeding with checklist 412, were currently 20 seconds ahead of schedule.” After that, they finally uncoupled from the ship, and headed back to the planet. The next crew launched right away, with Jenrick hauling the eggheads Jesla and Stelemma to the station with barely a snag for another 50-day stay. ---------- The KSC seemed to be developing an affinity for night launches. Hermes-C was one. Ultimately, Val took the pilot seat. The launch went normally; each individual part of the booster, including the six Reliant motors, was already considered tried and true. Hermes-C used a slightly modified version of the TDE manoeuvre. Much of the two mission vehicles was still hidden under a fairing. After the ejection burn, the ship would separate, and reattach with its forward docking port. However, the second ship was no mere airlock, and the stage was not to be jettisoned. Instead, it had an extendable active radiator array to stave off hydrogen loss during the five-hour trip to Mun orbit. The Tunguska engine was to be used for the orbital insertion burn. It was to reignite for a third time, and it worked flawlessly, putting the whole circus into a parking orbit. ---------- Two hours of later, as the crew run through another battery of checklists, Val was coming to the realization that she was wishing harm on a fellow crewmember. Bob was still the primary to take the single-seat lander to the surface. Finally, Bob had strapped himself into the craft, and they closed the hatches. “Propulsion, check, guidance, check, LS, check, comms, please confirm?” “Check,” Val answered. “Flight, permission to undock and initiate descent?” “Granted.” “Hermes, undocking.” There were clicks and growls. “Negative on undock. Bill!” “Looks like mechanical, we’ve still got electric linked. Relatching.” The sound of the grippers reengaging reverbated through both ships. “Val, give me forward RCS thrust.” The latches clicked again. “Retro!” And the Hermes drifted free of the Gadfly and the transfer stage. Val flipped it end-over and into stationkeeping position. “Hm. I guess that solves it,” came Bob’s voice as he reoriented his own craft. They drifted for a few minutes until the point where Bob was to initiate the suicide burn. The engine reignited one last time. “See you on the other side, Hermes,” he remarked, as the acceleration of the mostly-empty and lightly loaded stage pressed on him. The Gadfly was a very compact design, and it made plenty of sacrifices. Good radio was one of them. The primary antenna could only reach 500 km, with a secondary whip deployable for up to 2000 km; the Hermes had to act as a relay to Kerbin. And because of the descent trajectory, it was rapidly slipping out of sight; the landing used Pathfinder’s automation. The stage finished killing his downrange velocity, and was jettisoned, leaving him with the lander’s own motor. The Spark ignited early, bearing a pretty heavy load. Nevertheless, it did its job, and the ship hovered precociously above the bright regolith before touching down. A rookie might have gotten taken away, but for Bob, this was a bit mundane. Nor did he have anyone within radio range for the next thirty minutes. He was going to run the flight plan all by his lonesome. After setting the radio beacon, he opened the science payload panel, and flipped the switches. On the side of the propulsion system, a small drill head dropped into the ground, and began to spin, its whirr only barely audible inside the cabin. Next, Bob clamped on his helmet, and engaged the pumps. The Master Alarm barked at him. Life support readings were flat; no way this was real, but he had to sit through a computer restart before the system came to. The ladder on the Gadfly was rather short, and the whole lander was a lot stouter than the monstrosity assembled for Sarnus V. He had no problem getting down. The landscape was not novel to him, so first he attended to the science packages that festooned the lander. The exposure canister had locked open as needed, and the drill was hard at work, powered by the fixed solar panels dotting the hull. He had some minor electrical worries. It was midday, so the panels were barely getting any power. But the lander specifications stated that the drill could cycle fully without draining the battery bank anyway, so he went onwards. The landing site was almost at the rim of the so-called Farside Crater, visible edge-on from Kerbin had it not been for a mountain range. The flight plan called for two major EVAs; Bob had appropriately been supplied with a high-energy hydrogen peroxide flight pack. The first jump was to the crater’s rim, 5 km away. So Bob took flight. It was a delicate balancing act, having to keep vertical velocity under control, while not overexpending fuel and not crashing to death – Mun’s low gravity was quite deceptive. He hovered to a halt about fifty meters from the target, and then glided to a neat, soft landing. He trotted to the actual rim, and performed a quick panorama shoot. In front of him spanned the crater itself, with steep edges at his feet. The regolith in it was pronouncedly darker. However, unlike conventional craters, or because it was quite old, it had a considerable central uplift taking the shape of a colossal dome, almost at the same level as he was standing on. He scooped up a few rocks, but he didn’t expect to find much impact material, and he hardly fancied an unprepared trip down the slopes. He blasted off in a ballistic arc. The edge of Kerbin appeared as he was passing through the apoapsis. He maneuvered to a landing near his ship, and got in. Jeb’s early work had led to a mandated 3-hour period between EVAs. The interior of the pod was even comfier than that of the Hermes. Bob watched the snack wrappers glide down in the low gravity. “Away Team, this is Hermes, how copy, over,” Val’s voice came through. Bob almost choke up on his snack. “Gadfly, we’re seeing your beacon, please respond, over.” “Hermes, I copy, situation nominal here… had to eliminate minor suffocation hazard, completed EVA 1. How’s it on your end?” “Boring. Anything to share?” “I’m sinking a drill into this here mountain, so I’ll have major news in about one-two orbits. Think I’m gonna go for a nap, don’t be surprized if I fail to report.” ---------- “Hermes to Gadfly, wake up, buttercup!” “Whoa… oh dear, it’s three hours already!” “So, how’s the drilling?” In addition to a core sample drill, the payload included its own on-board x-ray spectrograph. Bob finally managed to fully open his eyes. “Feldspar. Aluminium and calcium, no iron or titanium. Largely same as Kerbin. Means it’s not impact ejecta. We’ll know more at the lab, gotta run the second jump,” he babbled, pulling the fuel canister from the storage rack. He got out of the ship, and sighted down his target. The jump was a wee bit longer and uphill: the aim was near the top of the mountain ridge. He checked if the flag package was still with him, and went to business. The landing was a bit rougher, but he was still sharp and in business. A mere 7 km had allowed him to come back into sight of Kerbin. He scooped up a few more Munar mountain rocks, found a spot with relatively soft soil, and thrust the flagstaff into it before deploying the flag itself. “Away Team, how copy, over,” Jeb’s tired voice came over the comms. “Good copy, go ahead.” He wouldn’t be able to stay connected for long. “That range you’re standing on is now officially Montes Triumphi.” “I take it you haven’t arranged it with the KAS, have you?” “If they want to change it, they’ll have to get there themselves. Meanwhile I’ll be making money selling ‘revised’ atlases.” During the jump back, Bob got brazen enough to pull off a panorama in mid-flight. After pulling out all the samples from the exposure unit and drill, and clambering back into his lander, Bob paused. Why was that getting so routine for him? Was it because the LZ was typical and hence there was little immediate gratification. He’d been where no geologist had – twice – and has thus far felt none of the expected elation. A lot of what he was seeing had been predicted in advance. He had to get to Minmus – or, at least, get a drill to Minmus. “Gadfly, how copy?” “I copy. Bill, mind running a diagnostic? I’m planning to attempt a Mode 2 blast-off right away, put a staging orbit at 50 and then fire up an automated rendezvous. Val, are you good with this?” There was silence on the other end. Mode 1 required the Hermes to guide the lander into a direct rendezvous; Mode 2 locked Val out of the loop, and required more manoeuvring from the lander. “Proceed,” Val finally called out. “Technical, clear,” Bill added. “Copy that, all systems in ascent mode, launching in five, four, three…” The small engine still strained to put the lander into orbit, but it managed, even though it was going on fumes. But manoeuvres in Munar orbit were a tenth of what they were around Kerbin, so the autopilot used those fumes to stage an intercept. Although Bob had had stable radio contact by then, he found himself considerably spooked – the rendezvous was occurring on the night side. However, the issue proved nil as Hermes’s windows lit up nearby, and the docking radar achieved a stable lock. Bob didn’t pretend to be an ace pilot and simply allowed the autopilot to dock the craft. The hatches clicked open one by one. Val’s grinning face appeared above him. There wasn’t much need for words; Bob averted any niceties by shoving a sample bag into her arms. The two began unloading the lander as Bill, stoic as ever, stood watch at the controls. An hour later, the finished, and sealed off the lander. The scuttling procedure was to take place next. The lander undocked – this time, curiously, without incident – and began to float clear of the ship. Then both its main motor and its prograde RCS fired, sending the Gadfly down its second and final descent. After that, the return was uneventful.

That's just one of the big points. You also have GPS, which is irreplaceable outside major cities where "AGPS" cannot be relied upon. And then there are all the other forms of mapping and imaging. Doesn't really justify manned spaceflight, but that's a whole other kan of worms.

Say I'm taking a ship from a 1.1.2-era .craft file to Munar orbit. Intermittently I get the issue of the craft not responding to thrust when the time for Mun orbit injection comes; fuel is spent, thrust is generated, but no acceleration occurs. Reading into the debug console, I've spotted OrbitDriver kicking out errors. I therefore presume that the craft remains on rails even outside of warp. So, I baked this log for you: https://1drv.ms/t/s!AmlSZuL0ax7C0Aepa6i_yUhKW3PT Mod list courtesy of AVC:

I'm about to generate a report myself. It doesn't seem to be version or mod-related. It's the updated physics keeping you on-rails and thus your orbit fixed.

Nice. Now I have an app for easy fixing, and a visage of Yuri Gagarin guarding my saves against future bugs. Off to the next bug!

Not necessarily. Humans can evolve their technology much faster than biological evolution in organism of their size and complexity can evolve itself.

The lack of actual gravity will still be an issue. It can't be fully compensated through muscular exercise. At that point we might as well break out Wolverine-style regeneration...

I'm taking a ship from a 1.1.2-era .craft file to Munar orbit. In addition to experiencing intermittent OrbitDriver issues consisting of the ship staying on the rails outside of time warp after crossing Mun's SOI - which I will be reproducing once I rescue this ship - I have the issue of the Undock command doing nothing and disappearing. I've also observed buggy staging compared to 1.1.2. The same issues seem to fail to show up when not crossing SOIs. Have attempted to remove KJR and Docking Sound mods; no effect. Have tried editing the save file to render the command Active; no effect. Mod list courtesy of AVC: Log file at https://1drv.ms/t/s!AmlSZuL0ax7C0Ac5y3Zem-13Vq1w

Interlude: The Wraps Come Off “Athens, you hearing us?” Jeb asked, adjusting the radio and microphone in the conference room. “Yeah, we copy,” Slava Kerbalov responded hundreds of miles above, with the rest of the upper-level staff sitting back. Then the lights went out. “Third time this week,” Gene sighed. “What’s with the municipal repair team? Do they keep slipping on banana peels or something?” Val wondered idly. “We’re installing a Prometheus reactor in one of our basement sublevels right now,” Bill smiled thinly, “For ’endurance testing of nuclear energetic apparata’.” Jeb did his best impression of an evil laugh as the lights kicked back in. “Right, back to business. Short-term flight agenda. Hermes-B to Minmus, conclusion of Athens Expedition-1, and the first Hermes-C mission. Any objections?” Hermes-C, in plastic miniature form, stood before them. Half of the fairing had been removed, revealing the Gadfly lander tucked between the ship and the upper stage. The lower stage had six Reliant boosters as originally envisioned, along with a slightly cut-down Mainsail sustainer. “Who are we sending up on the two missions?” Val asked wearily. “It’s a pretty good question. I say we send a rookie crew to Minmus for shakedown and field training. We’ll also need another, scientist-heavy crew for Expedition 2, plus I’d like to get with the program and have the station-rated pilots do trial runs with a Vector first,” Jeb mused. “And the Munar landing?” “Here’s where it gets very interesting. The Gadfly is supposed to be light on manned input, so I was thinking of sending Bob down with the rest of the Gold gang flying the orbiter. The single-seat lander means we can reasonably have a back-up pilot with remote vehicle control certification as well.” He traced Val’s look, and added, “I’m not that terribly anxious to go.” There was another moment of awkward silence. “Bill, the R&D section,” Jeb finally mouthed. “Currently we’re working on no less than five design concepts, most of them early-stage. We’ve got Linus and Gene’s interplanetary probes, mostly in subsystem endurance tests; they’ll be ready by the next Duna launch window. “But, of course, none of the rest of you really care about that,” he smiled thinly again, “So here are the interesting bits: Piraeus, Vulkan, Hermes Mk 2 and Hermes-Cargo. “Wait, we’re barely into the fourth flight and you’re already planning to replace the Hermes?” Val piped up as usual. “Only in orbital missions. We’re going to compromise on engine performance and modularity by introducing a unified fuel system, but we’re planning to double life support duration while developing re-use of the return vehicle and a new booster to almost halve the cost per flight.” Jeb furrowed his eyebrows. “There are certain fundamental disagreements left,” Bill added, “And in the same vein we’re designing Piraeus as the next station.” “Athens won’t be accepting Hermeses after Expedition 2; we’ve already geared it for bio-med research and it has a docking collar for Vulkan cruisers. Piraeus will have a lot more varied capability, we’re working on a new aft section,” Jeb explained. “Cruisers!?” Walt exclaimed. “That’s still deeply classified” Jeb hissed, “We’re working on a heavy ship habitable for a full year, with closed-cycle life support, and a significantly refitted RV. For initial trials it will be using Athens for power and the science gear we’ve carted up there; once we’ve confirmed that its gear works as advertised, we’ll slap an interplanetary nuclear tug to it. That’s why it has an oversized docking ring, it’s a thrust frame.” ---------- The meeting had degenerated into a fierce interrogation of Jeb, rudely interrupted by Mortimer, who fainted when Jeb began to at length about a reusable Munar ship with a pebble bed reactor rocket. “So, your solution to cost issues is building better boosters?” Val asked as the staff began to scatter about. “You’ve got a hunch on the ramjet toss idea, don’t you?” Jeb responded, “It’s not a terribly bad one…” “…especially with that afterburning pebble-bed you’re touting…” “…and I also must admit I’m intrigued by what winged descent vehicles would be like, but once we go into full swing in a month or two, the Mun program will really stretch us thin. I can’t commit fully to principally different launchers like that; best I can do now is scratch together a tiny experimental budget, which will be nowhere enough for your program to have much traction.” “My program?” “Yes, Val, if you’re that enthusiastic about the issue, I say we could spin it off along with our other reusability studies. But that may keep you out of orbit as a result.”

Well, we can pretty much exclude another Homo sapiens civilization unless we assume a stupendous degree of cover-up. Conspirologists are prone to imbuing The Man with incredible skill of erasing memories and picking up all the cigarette butts. As to dinosaurs, it's just doubtful that they in fact could. They seem to have lacked the sheer bio-energetics needed to run the requisite neural machinery. No, we wouldn't find their society, but we aren't seeing any significant evolutionary tendency that could lead to a sentient species; at our current level of insight, we'd expect to see clearer evidence of "sauroprimates".

Issue resolved. Turns out CKAN is really crippled. [Log]: [Kopernicus]: StarLightSwitcher: Set active star => Sun [Log]: [ModularFlightIntegrator] CalculateSunBodyFlux already has an override [Error]: [SurfaceObject]: Cannot return to original parent, it no longer exists This has led me to dig around the Kopernicus page; CKAN failed to load the new version with a separate Modular Flight Integrator. Once I properly updated, I got power. Props to Steam user Toasty Buns for suggesting to dig in the debug, and a heads-up to @Thomas P. and @pjf; I've had a similar screw-up with Module Manager today, and a few other mods promptly kicked out updates via AVC.

I was migrating to 1.1.3 along with my ton of mods, and I noticed a nasty issue: even in Direct Sunlight, solar panels have flux and energy generation of 0.000; this is confirmed for both reskinned stock parts, Ven's small panels, and Nertea's large ones. I have no idea where this can even originate. Mod list courtesy of AVC: Log file at https://1drv.ms/t/s!AmlSZuL0ax7C0Ac5y3Zem-13Vq1w

This is going to sound absolutely moronic, but, @Ven et al, I'm still using a pruned and customized 1.8.3. I've carried over the install from 1.1.2, thinking that the general lack of plug-ins should lead to few issues. However, as of, there seems to be a blanket issue of some - but not all - new parts failing to load: I'm seeing the Breeze and the large cryo tanks, but the solars and small radial tanks are gone. EDIT: Sorry, I discovered that CKAN has left me with a Module Manager version that wasn't working at all.

Damn, I could swear the OP said "Apollo" and not "Spacerace" (sic). I remember my own entry exam. A sixty-second (no more, no less) verbal presentation on the issue. I botched it because I was afraid of saying too much.

Doubtful. Weather reports predate spaceflights, SatTV via Telstar dates back to 1962 and GPS-NAVSTAR... How does your teacher feel about precision-targeted nuclear-tipped intercontinental ballistic missiles?

Something something forcefield. Ultimately it's quite possible to angle the explosive ordnance so that the parasitic frag ends up in a short-lived orbit.

* sigh *

* cough * Shaped charge warheads are hypervelocity kinetic weapons, not plasma ones. They drive a stream of superplastic solid metal, not plasma.