Starman4308

I swear I'll only subject you to three of the 54 screenshots I took on this subject. One thing I noticed was how huge Jupiter's SOI was, big enough to see when zoomed out enough to see the Sun as well. Approaching Jupiter, with Io and possibly Saturn visible in the background. Jupiter receding, with the inner solar system as points of light in the background. Pad abort test of the Apollo capsule. Had to write a quick MM config to give it unmanned control capability. The direct-ascent unmanned mission went well, unlike the LOR attempts. I didn't need that fourth Minuteman SRM anyways. I took manual control for part of the descent (well, at least insofar as plugging a pitch into MechJeb's Smart ASS), since I was a little bit over-aggressive configuring the descent profile when landing on high terrain. Landed with just 32 m/sec of delta-V in the tanks: it was kinda scary in between high-gate and low-gate descent. No fancy script for ascent: just plugging in 90 degrees heading and a steadily decreasing pitch into MechJeb. Contract complete, and biological sample returned to Earth for analysis.

Very interesting video! I'll point out that the engineering complexities involved in regenerative cooling are enough that the RS-68, used by the Delta IV rockets, instead uses mechanically simpler ablative cooling, where they basically coat the interior of the rocket nozzle with a heatshield material. I also suspect regenerative cooling is part of what drives RP-1 being so heavily refined; you really don't want fuel passing over your nozzle to start coking and forming tars and deposits: you need those passages clear. Liquid oxygen isn't exactly a great choice either, on account of being liquid oxygen. I believe part of why the A-4 rockets produced by Germany in the 1940s used 70% alcohol in water was because that mixture has a cool flame temperature, which reduces stress on the engine.

No. Each Falcon upper stage is still probably on the order of ~$10 million to build. Compared to that, fueling up a BFR is peanuts.

That's essentially the plan: make BFR so robust it can go for a fair number of flights without significant refurbishment, and reuse the same vehicle for hundreds to thousands of flights. I have my doubts as to whether they'll reach the critical thresholds in terms of ease of reuse and booster loss rate, but if you take Musk's projected values at face value, the economics work out. It's a waste of a BFR launch in much the same way as putting a single passenger onto a 747 is a waste. It is, however, less of a waste than putting that single passenger onto a Cessna that flies only once before getting discarded. The BFR will be overkill, but hopefully reusable overkill, and that's what will drive down the cost of space access even further... assuming SpaceX can get it to work the way they want.

It's Musk's long-term goal. People can have dreams they're working towards, yes? Even ones that don't seem immediately practical?

Voyagers 2, 3, and 4 are all away and off to Jupiter! Arrivals are fairly staggered: Voyager I arrives in 2 years 43 days, with Voyager 4 arriving in 2 years 216 days. A small improvement to my usual execute-node script has them completing nodes on RCS thrusters, instead of the main thrusters. This helps ensure very precise maneuver execution, and with reaction wheels onboard all four Voyager probes, they can even be executed without a drop of propellant used to steer the craft. One possibly mildly-cheaty thing: I reverted to launch on Voyager 2. Late in the trans-Jovian injection burn, I suffered an RL-10 engine out, and the other three engines can't gimbal enough. Initially, I thought to myself "oh well; at least I can circularize on the probe at apogee and keep the RTGs from splashing into the ocean". About thirty seconds later, I realized I could've just shut down the engine opposite the one that had failed and still completed the mission. It was only at that point when I hit revert-to-launch. I also discovered where Jeb, Val, Bill, and Bob went. I also sent out two lunar landers with the intent of an LOR landing mission. A booster engine-out on the first attempt produced very narrow margins, and mis-configuration of the landing script ensured the lander crashed. Specifically, I'd set minThrottle to 0, without taking into account that A, it could throttle, and B, it needed ullage. It never recovered from the first shutdown. The second one suffered an RL-10 engine-out while still circularizing. While I tried to salvage it via shutting down the opposing RL-10, that meant the two remaining RL-10s had to burn far longer than what they were rated for. Unsurprisingly, I had a second flameout, and this time there would be no compensating for the steering. Funny enough, when revisiting the design, I've shaved down an LOR mission launching on my heaviest Gimel-6 booster (33k funds, nearly 800 tons) to a direct-ascent mission launching on the Aleph-Centaur 442, a quick redesign of the Aleph-Centaur 402 that uses a quartet of Minuteman SRBs and a stretched first-stage tank. This booster costs just 18k funds, massing 460 tons on the pad*. I hope this time it works: if these two lunar landers fail, I'm down a 1-year-deadline contract. *Heavier and less capable, but still cheaper than the Gimel-2 with those expensive hydrolox sustainers.

You still haven't shown that he couldn't land an 8-ton Dragon, merely that he's not planning to. Not every technological advance has to be purely incremental. Incremental advances are usually the path of caution, but nothing you've said proves SpaceX couldn't land a BFR on Mars the first time they try. I still think it would be wiser for SpaceX to test some of this technology and equipment with a smaller vehicle, but it's not impossible for the BFR to just work.

That's a misleading argument and you should know it. Both of these things were cancelled not because they were impossible or even really particularly difficult, they were cancelled because they think they can perform those missions more economically in the BFR. For example, I believe Elon Musk has stated that, if BFR takes longer than he hopes to get into service, he'll man-rate the Falcon Heavy anyways for the tourism slingshot. What he's decidedly not doing, however, is continuing to sink time and money into developing a platform that he thinks he might abandon, particularly when the closest thing to a contractual obligation he has is to send tourists around the moon.

Mostly, I agree with that, though I would say most of Elon Musk's publicly announced timelines have... loose relationships with the timelines that will actually happen.

First, I think you missed the point about political shackles. In the case of the Space Shuttle, to satisfy all the overlapping mission requirements, they had to engineer the RS-25 into being one of the most complicated, expensive engines ever built. I think you're also conveniently ignoring the fact that the "crew cabin" also had all of the liquid-fueled engines onboard: 3 RS-25 and 2 AJ-10 engines, plus miscellaneous RCS thrusters. Unlike the Falcon 9, which has a 10% engine loss rate from the expendable upper stage, the Space Shuttle brought them all home: the only piece of equipment totally expended was the external tank.

When it comes to the Gigantors, I'm a bit unsurprised they have very low thermal conductance. When you're taking probes in towards, say, Moho, then, you don't want them to be conducting much heat inwards towards the main vessel... and with that much surface area exposed to the sun, something tells me they're absorbing a fair chunk of solar thermal flux. Unless you're taking your vessel so close into the sun that a solar panel in equilibrium will explode, then, you want those to be thermally insulated from the rest of your vessel, essentially in their own little thermal equilibrium at a potentially higher-than-normal temperature.

Payload capacity: very heavily in favor of the SLS. Fairing size: very heavily in favor of the SLS. Main engine specific impulse: very heavily in favor of the SLS. Per-engine thrust: RS-25 has twice the thrust of a Merlin. Reuseability: in favor of the Falcon, with heavy assistance from NASA. Don't forget, though, that NASA reused rockets 128 times before SpaceX even attempted the feat. Cost: In favor of the Falcon and Falcon Heavy. Personally, despite being a fan of what Elon Musk has done with the Falcon 9/Heavy, I'm getting really tired of people misrepresenting what NASA does and the general disrespect for them. NASA can engineer a pretty good rocket, but, hobbled down by political considerations, they cannot produce it cheaply. NASA is not made of incompetent fools. A lot of America's finest scientists and engineers work there. If let loose to perform their secondary mission of exploring space, they might be a competitive launch provider. Unfortunately, their primary mission of being a glorified jobs program and political tool gets in the way of their secondary mission. Seriously, have some respect for the organization that helped pave the way for SpaceX's success, including a CRS contract that helped keep the company afloat as it just barely started. EDIT: I'm reminded of the situation with Japan circa World War 2. Japan had some excellent engineers; they just had issues mass-producing their best designs because of mediocre industrial practice. America, on the other hand, had management and industrial practice down to an art form, and was actually able to mass-produce a lot of the best designs made by their engineers. The M4 Sherman was a good example of the difference between engineering and industrial practice: while the heavier Panther and Tiger tanks it faced were in many ways superior, the M4 Sherman could be built in large numbers, and more importantly, still transported on regular railcars and ships.

I think SpaceX is around $2700/kg to LEO, $15400/kg to Mars transfer*. *Used mostly as an OOM estimate for the cost of sending mining equipment to an asteroid. My guess is the cost would be worse, because you'd be sending some fairly sophisticated (thus expensive) kilograms to that asteroid, plus needing to rendezvous, etc. Still, platinum is around $54,000/kg. If you can scale up to the point where you can get around 1 kg of platinum out of an asteroid per kilogram sent to that asteroid in the first place, you're approaching the point of at least marginal profitability... at least until you crash the entire platinum market. If we were able to extract platinum in sufficient quantities to crash the market... unfortunately I just don't know enough about its industrial or commercial applications to say much. The one thing I would say is that De Beers would probably start to advertise "natural" platinum extracted from Earth as being the perfect romantic metal to set your natural, mined diamonds in. I do not like De Beers.

Thanks for the help. Part of what I was looking for was less planning the initial transfer window (one can just look up the original Voyager launch dates for that), and more help on the very fine fine-tuning involved necessary to set up a quadruple-slingshot. Right now, I'm probably going to wind up substituting the elegance of a quadruple-slingshot for just firing off four probes; Voyager 1 is set for a Jupiter-Neptune-Uranus trajectory, for example, skipping Saturn. Besides, given that I have vastly more delta-V than the real Voyager probes, around 3 km/sec more, I can accomplish more ambitious objectives, such as Voyager 1, which will be orbiting Uranus instead of a mere flyby. I might still manage a quadruple-slingshot on Voyager 2, for that matter, abusing the Oberth effect at perijove to still reach Saturn despite a very close flyby.

I strongly regret the fact that I cannot remember my first exposure. What little I do remember is mostly struggling to figure out how to steer the rocket (I had not yet learned that I should steer by looking at the navball), and initially having no idea what the maneuver nodes were for. I persevered, though, and now I've gotten reasonably good at the game. I do also recall my brother finding KSP, thinking this would be perfect for me, only to find out I already had the game.

Quick question: is that total stage delta-V, or delta-V after reaching LEO parking orbit? One of the major factors I can think of, though, is the question of how necessary these high delta-V values are. We've gotten quite good at creating some excellent multi-slingshot trajectories. Similar back-of-the-napkin (well, more like back-of-the-Excel-spreadsheet) math puts a conventional Atlas 551 with short payload fairing as being capable of putting 1.7 tons onto a Jovian slingshot, and if we assume an EEJ slingshot (5.4 km/sec ejection burn from LEO parking orbit), that goes up to about 2.8 tons. My best guess is that I've lowballed it, since Juno was 3.6 tons at launch, from an Atlas 551. Probes are getting smaller and lighter recently; a recent flagship-class proposal for the ice giants proposed a 150 kg orbiter plus 50 kg probe as its most ambitious proposal. I'll be conservative and put an orbiter dry mass at 500 kg. Even at that level, with a 310 s-1 hypergolic engine and 2.8 tons ejected on an EEJ trajectory, that still gives you 5.2 km/sec to play with once you hit Jupiter, or presumably whatever you're using Jupiter to slingshot to. For unmanned missions, then, I would agree with NASA's trend of keeping it conservative, of keeping development costs low by relying on chemical engines supplemented by slingshots. Where these very high-velocity Earth ejections really come in handy is for manned missions, where you can't spend years mucking around getting your slingshots, because your astronauts are not exactly getting any younger. For that, I'd probably assume a custom-built vehicle assembled over multiple HLV/SHLV launches, because I don't think you're sending astronauts to Mars on top of a single Atlas 551, even if you do replace the RL-10s with nuclear thermal rocket engines.

It is time. The heavens are aligned. The sacrifices are ready. All has been prepared as it has been set out years before. VOYAGER I PRIMARY MISSION OBJECTIVES: Flyby Jupiter and Uranus Orbit Neptune Flyby Triton STATUS: En route to Jupiter. First correction burn in 227 days. Over 3 km/sec of MMH/MON3 in the tanks after both planned correction burns, and over 2 km/sec after entering elliptical Neptune orbit. I may have slightly overengineered these probes... I tried to get the historical quadruple-flyby, but the correction burns weren't cooperating, possibly due to being early in the window. I got the Uranus flyby on pure accident trying to set up the Saturn flyby, so I basically abandoned the Saturn flyby. Funny enough, I noticed I could get the Saturn flyby... on the way back inwards! I'm also very confident now in the Gimel-4 launcher: I had 300 m/sec left in the Centaur upper stage, of which 90 m/sec was burned about an hour after Jovian injection, since with cryogenic hydrolox, it's use-it-or-lose-it. VOYAGER II PRIMARY MISSION OBJECTIVES Flyby Jupiter and Saturn Escape solar orbit, measure the heliopause (I even have the right equipment with a RWPS!) SECONDARY MISSION OBJECTIVES Flyby Uranus, Neptune Boost solar escape velocity to maximum possible at final slingshot. STATUS: 26 minutes to launch. VOYAGER III PRIMARY MISSION OBJECTIVES Flyby Jupiter Orbit Uranus, avoid truly juvenile humor SECONDARY MISSION OBJECTIVES Flyby Saturn VOYAGER IV PRIMARY MISSION OBJECTIVES Flyby Jupiter Orbit Saturn, flyby Titan SECONDARY MISSION OBJECTIVES Flyby all the moons! I've also launched the final Mercury 1B, carrying engineer Craig Lane to orbit. Further manned missions will await design of a more capable vehicle; I still haven't decided on whether to focus on an enhanced Mercury, a Gemini, or even an Apollo-style vehicle. Testing a new sounding rocket design: Successfully docked a pair of unmanned vehicles in LEO, launched on R6-Agena vehicles. Lessons learned include use of spin-stabilization to hold orientation during much of the approach to conserve precious RCS fuel.

Parts with a high maximum temperature, such as spaceplane parts. A lot of those can survive gentle reentries without a heatshield.

Went after a contract to get a high-resolution SAR altimetry map of the Moon. The SAR unit from ScanSAT masses a mere 50 kilograms, which is good, and consumes 1.5 kW, which as I understand is the limit for how much a wall power outlet can safely provide. To get that power output using roughly 1960s/1970s photovoltaic cells requires about 8.4 m^2 of solar panelage massing 17.5 kg assuming it's pointed straight at the Sun. To make sure I could power this on a spin-stabilized craft, I went with a total of 8 ST4 static solar panels for 84 kg. While the mass of these is a bit of a pain, the bigger issue is just that they are huge. Now that its primary mission of mapping the Moon is complete, I may repurpose it a tad; it has both the standard 4 Mm Communotron 16 omni and a 75 Mm high-gain dish. For most of the Moon's orbit, the 4 Mm antenna is just barely enough to talk to the immensely powerful dishes of the Deep Space Network, so I can repoint the HGA to the active vessel. That means that, in some circumstances, it could help provide communication coverage on the far side of the Moon, or to vessels with omni antennae too weak to reach the Earth. The Pioneer probes I'm now constructing are intended to get radar and SAR maps of Venus and Mars. They carry no other scientific instruments, just mapping equipment, a quartet of ST4 panels, and a pair of rotating OX-4M 2x3 panels (410 watts, 17.8 kg). This will be more than enough for Venus, but I'm going to have to pulse the SAR unit at Mars. They'll be going up on Gimel-2 boosters; while the science/control/communications payload is relatively light at 451 kg, they'll need well over 4 km/sec once there to get into the 500x500 km orbit required by the radar unit. Coming off the stack soon will be a pair of lunar landers... and service modules capable of returning their science sections to Earth. I think I have them going up on Gimel-4 boosters, which provided enough margin to give both the service module and lander a bit of extra propellant.

There's an atmosphereCurve entry in the part .cfg file. IIRC, they're used to define a cubic Hermite spline. Unfortunately I don't know of anything in the stock VAB/SPH GUI that provides arbitrary-pressure specific impulse measurements, and it's not like you can just open your favorite text editor and have a looksee at the game files on console.

You see the window that pops up beneath the main kOS terminal? That is the kOS file editor, where you need to be editing the file "hello". The kOS file editor isn't the greatest in the world; particularly if you dual-screen, you may want to look into other text editors like Sublime or Notepad++. Do note that "text editor" tends to exclude office software like Microsoft Word. A .docx file is not a raw, UTF-8 encoded text file: there's a whole lot of other stuff in there.

SpaceY has 3.75m and 5m docking ports as well. Not to my knowledge. I know it has some Real Fuels configs for either stockalike RF or RO, but it should also work in stock running LF/O.

So, correct me if I'm wrong, but I'm under the impression it's at least semi-okay to ask for RO advice here? The Voyager window is coming up for my RP-0 campaign, and I'm wondering if there is any advice, tutorials, or historical data on exactly how to plan the ejection from Earth so as to get cheap flybys of all of the four outer planets. Even just detailed information on the Voyager orbits and flybys would give me information on how to plan ejection and any correction maneuvers.

My immediate suspicion is that your heatshield is too small, and not fully shielding everything behind it. Behind your heatshield, your reentry vehicle should taper inwards like this: (> Heatshields are not magic deflector shields, and reentry plasma likes to curl in a bit from the edge of your heatshield. The cone of your reentry vehicle has to come to a point inside the cone of the reentry plasma. Your other parts are probably also frying, but the Able avionics package has the lowest heat tolerance out of all the parts on your reentry vehicle (573K internal, 773K skin), so that's what explodes first.

Wait for it to go on sale? Steam frequently discounts KSP. In any event, the framerate thing is dependent on the PC used to run it. A weak CPU on a PC isn't going to be any faster than a weak CPU on an Xbox. Anyways, mods let you totally change the experience. There are mods for: scripting your vehicles (such as my automated lunar lander script), upscaling the solar system, adding to, altering, or wholesale replacing the solar system, adding additional bits of realism to worry about (life support, powering your communications, ullage and cryogenic fuels), improving the aerodynamics model, building larger rockets, adding new science experiments and mechanics... there's a lot that's been done by KSP modders. The controls are probably also somewhat more natural, and editing in the VAB/SPH is probably easier with a mouse for precision adjustments.