Rune
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Posts posted by Rune
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19 hours ago, kermand said:
Very nice summary, thank you, but i have a question about this point.
How about RCS blocks ? I just designed an SSTO for 6 kerbals, the ultra basic LKO station crew swapping model, which gives me satisfaction appart for the fact that the RCS blocks on the side and below tend to explode on re-entry. Do you put them in cargo bays ? (It could fit in a small one)
Hi! Well, RCS blocks do have a few things to keep in mind. First, they are physicsless parts, IIRC, which means that, on their own, they generate no drag. Or rather, they don't generate drag on themselves, but they do add to the drag (and weight and so on) of the part they are attached to.
Which means, you could probably exploit that, place them on a shielded part inside a cargo bay, move them outside with gizmos, and unless I'm mistaken you would have drag-less RCS ports. Not that I actually do such things, but it's the way I think that would work.
Now, what I do, that's different. First, I eat the drag as a small inefficiency, just like I sometimes place parts for aesthetic purposes only. Once you design an ultra-efficient prototype, you can tape more stuff on to it, to make it also practical.
And of course, I never use the four-way RCS block on spaceplanes. Temp. rating is a measly 1500°, and it looks very wonky in any case (IMO, YMMV, and all that). Instead, linear RCS ports can be hidden quite flush, and both them and the uber-powerful (and expensive!) Vernors have temp. ratings of about 2000°, which is much more reasonable to handle your typical reentry.
Besides, you can try some weird ways of getting six-degree control authority that way, and some of those can actually tailor your RCS subsystem to you plane's actual moments of inertia on each axis (a long plane has big moment of inertia in the yaw axis, but a small one in roll). A few more parts than the 4x RCS blocks radially spaces 45° that we always use, but a nice change sometimes!
Rune. Experimentation is encouraged.
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1 hour ago, katateochi said:
@Raptor9 you are one of the most active uploaders and I really appreciate your support of KerbalX! So yes, consider me lobbied! I will add a bulk-zipped download feature, probably to craft hangars, rather than a 'download all users craft' option. In the past there have been people (bots?) who've tried to scrape content off the site and set up "mirror" hosts of the craft, and so I've put up methods to make script downloading difficult (without having to have annoying recaptcha checks), so I want to make sure a bulk zip download option doesn't make it easy for those who just want to hoover up all the craft and re-host them (this might involve having a recaptcha).
I'm away for the first half of this week, but should have some time after wed to start adding this, so maybe by next weekend there'll be something. I really appreciate your decision to keep the downloads through KerbalX and not setup an alternative bulk download option, so I hope adding a bulk zip-download for craft hangars will meet your requirements.
His won't be the only requirements met, good idea all around!
Rune. Ain't feedback cool?
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20 hours ago, EpicSpaceTroll139 said:
FINALLY IT WORKS!
IT *bleep*-ING WORKS!
YES! YES! YES!
It's 294 parts tho... without the big A rocket attached... I might have some ideas for how to reduce part count, but not by a significant amount.
If that does what I think it does... dude. That's complicated. How many independent craft while on operation?
Rune. Totally useless, but in a very spectacular way.
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2 hours ago, mystik said:
This is good for local SSTO, but if you want to go build a SSTA you cannot use RAPIERS as they are a lot of weight to carry around. I found that a ship can go to space using a combination of RAPIERS and a single Vector engine. My ship is about 300t and I can fly it with 6 rapiers and 1 Vector. It can successfully land on Tylo. Tested. It can reach Moho. It is part of a two stage ship. The lander (which is a space plane) and a space tug, that it docks to and travels to places.
It could not do the distance with rapiers alone. They are heavy and not that efficient if you want to go far. So, I kept them to a minimum, then burn the Vector until it reaches 400m/s then shut it down and so I get past the 400m/s barrier without needing to use all exclusive rapier setup. The reason why my ship uses no nukes is that you cannot rely on nukes to land on Tylo. It just does not work. The tug uses nukes because it only needs to land on low gravity objects to refuel, but the real workhorse is the lander spaceplane, and the hardest place to land on is Tylo. It is very stressful to not overdo it and get the landing right with only a few hundred m/s left before touchdown.
I have been lazy recently but I am looking to post my ship and thus enable full exploration of the KSP solar system. Rapiers are great for local travel. Long distance they kinda add weight and reduce the DV you can store without ending up with a gigantic ship. I have made a SSTO that weighs very little with one rapier and it works. But as you can tell, it is for one crew transfer to the space station and back, or for returning astronauts from rescue missions.
A lot of people bring this up when I talk about the RAPIER being the only sensible solution for SSTO... and it's completely irrelevant. We are talking about Single Stage To Orbit. Not Tylo, not Layhte, not Minmus, and not Duna. Obviously the RAPIER is not the best engine for in-space travel. The nukes are. So count your nuke as part of the payload fraction of your mostly-rapier-powered plane-thing, and you have yourself the longest-range single stages in the game (I am intentionally ignoring ions, because that is not the point I'm making).
And if we are talking about SSTAnywhere and Vectors... well, I have this. No intakes.
Rune. And I have an even better one without wings. But that's untested.
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1 hour ago, Parkaboy said:
Good news, everybody! After Cydonian Monk's advice, I realized what the issue with the save probably was: the game crashed the last time I played it, so it probably generated a messed up file. So I just replaced the persistence with the last quicksave and everything is back to normal (except for the long loading times, I can't figure out those). I'm beating myself up for not realising that sooner. Thank you all very much and we'll be back with a new chapter soon!
Backup the backups. In triplicate.
Rune. Close calls are IT's way of saying "when was the last time you saved everything to a backup disk?".
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On 21/4/2017 at 11:23 PM, sevenperforce said:
If SpaceX's plans for the Mars come to fruition, SpaceX would eventually want to transition Falcon 9 and Falcon Heavy payloads to a Raptor-based architecture, to enable access to space for payloads smaller than the full ITS/BFR/BFS capacity. On the flip side, if the Mars colonization plans never quite pan out, SpaceX will still need a use for their methalox engines. So either way, we need a Raptor-derived fully-reusable TSTO with payloads roughly equivalent to the Falcon family. It will need to be man-rated, too, since there will surely be a need for sending passengers to orbit in numbers lower than the 100+ capacity of the ITS/BFR/BFS system.
One problem with this is that a single-engine upper stage has a TWR too high to use for propulsive landing, even if it wasn't overexpanded at sea level. Thus, it needs auxiliary landing thrusters. Another problem is re-entry; an unmanned stage can come back using a heat shield on its nose, but that's not much fun for passengers, and I have a strong preference for a "true" TSTO where the crew cabin is integrated. You need biconic re-entry a la ITS. But if you're already using auxiliary thrusters and biconic re-entry, you don't necessarily have to align the aux thrusters with the main engine vector. That's where things get...interesting.
Here is a line drawing and a very very rough sketch of my concept:
Looks a bit like the ITS, doesn't it? Same basic principle (composite monocoque tanks, etc), except the diameter is only four meters, making it roughly the same size as the Falcon 9 but slightly wider.
The first stage has two full-size SL Raptor engines for launch and boostback and six methalox hot gas SL thrusters for landing, along with four landing legs:
The first stage has a dry mass of 17 tonnes and a propellant capacity of 421 tonnes; it delivers the upper stage at a notional staging velocity between 1.5 and 2.5 km/s and executes a boostback RTLS landing. Minimum initial TWR for the boostback burn is 2.7:1 with both Raptors at minimum throttle; maximum landing TWR on thrusters alone is 3:1 but it can easily hover. I've factored in the masses of the thrusters and everything else.
The upper stage is where it gets really interesting. Rather than using Raptor engines, which would be way oversized, it uses a pair of the Raptor Development engines (1,000 kN SL thrust) with vacuum nozzle extensions. I'm estimating their mass at 638 kg each. Total stage vacuum thrust is 2,292 kN. Dry mass is 6.6 tonnes and propellant capacity is 141 tonnes.
Because the vacuum engines cannot be used at sea level, I gave the upper stage eight SL-expanded methalox thrusters in addition to its vacuum-optimized RCS thrusters, with a combined SL thrust of 688 kN. But I didn't want to cluster them around the devRaptors in the tail, both for space considerations and because of damage to the engine bells.
See the wing extensions shown in the above line drawing? The landing thrusters are placed underneath the wing extensions, pointing down. For re-entry, the upper stage enters biconically, on its belly. It then glides/falls to the landing site before hydraulically-actuated panels open up underneath the wing extensions, both exposing the landing thrusters and providing rear "legs" for the vehicle to land on, so it lands vertically but in a horizontal attitude, eliminating the risk of tip-over. The landing would look like something out of Star Wars, because it drops, winglets open, and it lands on the wingtips with rocket propulsion.
Based on my simulations using this calculator, the launch system could deliver up to 6.8 tonnes to GTO with full reuse or up to 24 tonnes to LEO with full reuse. For LEO launches, the upper stage can also recover up to 30 tonnes of downmass. This is obviously plenty of margin to have a crewed version, which would use the same tank and body as the rest of the orbiter but have a crew cabin in place of the cargo bay. Payload capacity is high enough that the crew cabin could carry at least a dozen crew members plus unpressurized cargo and still have independent LES and re-entry capability (lifeboat).
Know what else is great? Due to the vertically-oriented thrusters, the upper stage could both land on and take off from the Moon or from the surface of Mars without needing a launch pad. On Mars, it would need to be refueled on the Martian surface; the lower gravity means that the thrusters have enough thrust to lift it off the ground so the main engines could be fired up. For lunar missions, simply being refueled once in LEO would give it ample dV to fly to the moon, land, SSTO, and return to LEO.
I like the idea, but stability. It's the one thing that also irks me about ITS, how the heck do they control the attitude during reentry. The CG/CP positions must be very tightly controlled for such a thing (forget forcing things propulsively if you are trying to brake aerodynamically), and you have, at the very least, a cargo bay that might or might not be full. You need something ballast-y on the nose to balance the engines, but you need that to stay put and maintain its weight. Oh, and you need to account for varying fuel levels, or a tank at the CoM. And last but not least, it would be nice if the thing more or less stays rigid during reentry, which means it is capable of maintaining shape when empty and decelerating laterally at some 3Gs or more. Or with a full payload bay and doing the same, which would be more impressive, if you want downmass.
I mean, if you can work it out without too many structural efficiency sacrifices, yeah, great concept. But I would like a full structural/thermal/aerodynamic load analysis before assigning a mass fraction to that stage, unless I use a "fudge factor" of about 2. So you'll excuse me if I take your numbers with a grain of salt the size of some metaphorical houses.
Oh, and the thing about single-staging to the Moon and back from LEO... you are aware that is 6km/s each way, right? At least nine for the roundtrip, and that's with a high-velocity reentry directly from the Moon, several times harder than any LEO reentry. How much dV do you want to pack in this stage, again?
On 22/4/2017 at 0:50 AM, Frozen_Heart said:Don't actually agree with landing it on its side as it would need a much larger heat shield, and so more weight. With the ITS it is probably needed due to the way mass scales faster than surface area, but for somthing smaller a nose or tail first approach and landing would be more efficient.
Actually, as has been said already, high surface area is nice, because it lowers peak heating. A big ballistic coefficient is always nice on reentry. And if you can use "only" ceramics and high-temperature metallic alloys, you might have a reusable non-ablative heatshield like the shuttle. Which will be much safer because it sits on top of its first stage, not at the side and facing it.
Rune. That being said, I believe reusable TSTO is doable, even in an economical way, at least for launches to LEO.
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21 hours ago, Shadowmage said:
One of the best transfers and maneuvers I ever managed to wrangle, was this Jool insertion and multi-moon encounter setup. Capturing at Jool and getting flybys of 4 out of 5 moons for <100dV, no dedicated insertion/braking burn (and the fifth moon likely doable for very little extra dV, once I get closer and can get more accurate trajectory predictions). This was all plotted from Kerbin orbit, and the maneuver shown on the dV widget is the ejection burn. Haven't gotten back to the game in a few weeks, but when I finally do, it is going to be one busy little probe returning scads of science from all the flybys and still having a few k of dV left in the tanks.
Apparently I misplaced the rest of the screenshots showing the rest of the flyby encounters. Sad. I'll have to load the game up and see if it is all still in place
Pretty cool! The Jool system really is the paradise of a good navigator, and the reason many of us end up learning how to grav-assist. And four moons without mid-corrections sounds sick!
13 hours ago, Cpt Kerbalkrunch said:This is my favorite orbital achievement thus far, and one of my biggest "aha" moments in KSP. Everybody probably does this, but the first time was a complete surprise (it was a lucky accident), and now it's something that I take for granted.
You can see that I'm about 2 years away from a Jool encounter. This is right after I made a slight correction at the node to set up a Tylo encounter.
I have the standard number of conics set (3 I believe), so in this next pic, I added an empty maneuver node (because it will add the extra conic to show your orbital path). Now you can see, even though my Tylo encounter is 2 years away, I already have an orbit around Jool.
If I want to, I can adjust the orbit anywhere along the way, depending on what I wanna do when I get there. But no matter what, I'll capture at Jool without needed a single drop of fuel. No dangerous aerobraking or lugging shields along. Just a nice, easy gravity brake that was set up 2 years earlier. And it works every single time. It's probably an ordinary accomplishment, but I'm extremely proud that I discovered it on my own.
Well, braking into a Joolian orbit using Tylo may be much more common than it once was, but it's still a pretty big accomplishment! Think about it, in the real world, it took NASA until the seventies to use the trick, with Mariner 10, to get it to Mercury. And you learned how to do it with a videogame! So yeah, welcome to the club of people that think planning complicated maneuvers is fun.
Rune. Any other navigators out there?
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3 hours ago, Majorjim! said:
@hazard-ish you are a proven poster of fake videos. Not only this one but the Tylo landing one too, goodness knows what other videos you cheated on. This is not stock, it is modded, and a lie. For shame. You changed the engine power and weight. On the rapier and the nerv.. What the hell are you playing at? You are making a mockery of those youtubers who work had to make great stock craft. This crap should be deleted from YT.
Dudes, watch it a little, please! There is a person at the other side of all those notifications. Yes, he lied to people, and he got caught. Bad on him, but he must be feeling pretty excrementsty already. And it's not like he lied while running for an election or something! This is a game, and whatever benefits he can get from his youtube account, a pittance at most. I'm just saying, put things in perspective, even if you like your daily dose of drama.
Rune. Be slow to anger, so that when you do get angry, it's for the right cause.
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34 minutes ago, regex said:
Orbital slingshots? Every. Damn. Day.
Cool one! That's, what, RSS? Care to explain the particulars of the situation, so we can be properly awed?
Rune. And perhaps learn something while we are at it!
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2 hours ago, Angel-125 said:
This really helps, thanks!
I will definitely bookmark your post and see what I come up with. I also didn't realize that open nodes slows down your craft! Gives me an idea for Wild Blue Tools... Thanks again for your help!
You are welcome! I had a feeling it was something like the node thing that was thwarting your efforts. One of those non-intuitive KSP things where it's not how you see it, it's how the aerodynamics model sees it.
Rune. Always glad to be of help.
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Ever felt like Kepler and Newton where sitting on your shoulders, whispering as you plotted a maneuver? Maybe you managed to plot a course that seemed impossible, and got your kerbals back home with the last drop of fuel. Perhaps plotted three gravity assists with a single node? Circularized around Jool with RCS and Tylo to await rescue, because you had horribly misjudged your dV, but are a heck of a navigator? Well this is the place to show off those navigational skillz! It's amazing what this game teaches us to do, so let's show off our intuitive understanding of orbital mechanics, and those feats of orbital maneuvering that made us feel like we were the guys at JPL.
I'll start with the one that prompted me to write this post, so you see what kind of thing I'm talking about. See, I was wrangling this asteroid, with not a lot of time (or engines), and I just managed to stop it at close approach, in a very weird 50º inclination (in my defense, I didn't see it until it came into kerbin's SOI, else I would have corrected the trajectory in solar orbit with plenty of time). Trouble is, the rock is about 1,700mT, and I only have four puny nukes on the ship tugging it. Even with a lot of fuel tank space for them, I can only get ~150m/s out of the tanks before I dry them and have to process more fuel, so I am limited in what I can do in a single burn. Changing that inclination and altitude by brute force, in any case, would take ages. So, what to do? Easy, just catch a ride on the Mun!
I highlighted the important bits so you can admire the thing, plotted in all its glory. Just two maneuvers totaling 67m/s! And you can't see it from there, but take my word for it, the resulting orbit is not only a lot lower (16,400x78kms vs 39,300x9,800kms), it also has pretty much zero inclination (the game won't tell me, but I did the trick of moving the camera to make it coincide with the Mun's orbital plane). Yay me! I totally felt like like a pro when I plotted that. The key is that Munar encounter, where I fiddled with the node more or less by gut feeling until I got closer and closer to what I wanted (use a gravity assist to kill my vertical motion and thus make my inclination 0º). It came out to around 51kms altitude, so I could actually gone a bit lower if I needed more change in velocity. Turns out I also go out on a very useful orbit, where I can move into an aerobrake to go lower down, or use another Mun encounter afterwards to circularize at around the Mun's altitude, with further small corrections. Isn't it awesome what you learn to do in KSP? And it's all done by Mk1 eyeball, not even precise node!
For completeness' sake, here's the "vehicle" I plotted this for, just before the very long capture burn that got me the initial "wherever it falls" Mun encounter.
Tip: to make good maneuver screenshots, you can make highlights persistent in map mode by right-clicking on stuff (manuver nodes, Ap/Pe nodes and all that stuff), and move the PoV around without clicking with Tab.
Rune. Now show me how you did it!
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12 minutes ago, Laughing Man said:
Why are they crappy? Do you mean in terms of the amount of fuel they hold relative to size? They do provide a bit of body lift too if I'm not mistaken.
As I said in the post @Angel-125 quoted, not only do they have one of the worst tankage ratios in the game (full weight/empty weight), they have horrible drag values. The short Mk1-Mk2 adapter, in particular, is murder. It has around... ¿four times? ¿more? Can't remember off the top of my head, but something horrendous... anyhow, several times the amount of drag of a similarly-sized Mk1 tank. And their lift values are nothing to write home about.
Rune. Check the thing I said about aerodynamic data in context menus, it's very informative.
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6 hours ago, Angel-125 said:
This might explain a few things. I've always been lousy at spaceplane design, and gave up on it entirely until this evening. The Mk2 designs I come up with just don't have the oomph to reach orbit, and I'm about ready to go back to flying rockets. I'll have to give this a try though. Also, if you know of a good SSTO tutorial for KSP 1.2, I'm all ears.
Actually, SSTOing in 1.2 is so easy once you know a couple of rules, I'm pretty sure I can cover anything important in a single post:
The key is to hit the right TWR and drag. Once you do that, the ascent profile is as easy as going in a straight line and switching the RAPIERs to closed cycle when appropriate! Basically, you go flat-ish at sea level until the RAPIERs hit the magic 400m/s (the point when their thrust curve gets to its sweet spot, and the RAPIERs continue increasing thrust as you climb), then just watch as your vertical speed increases as the planet curves down under you and you keep going in your straight line, until the air is thin enough that the RAPIERs start giving out. Can't be any simpler! You just have to make sure that your ship is able to hit those magic 400m/s at level flight at sea level, and the rest will take care of itself. And I seriously mean that, I need many more manual control inputs when grav-turning a rocket, than flying a SSTO to orbit, where I just have to take off and set the initial "climb".
Since rocketry is all about ratios, here are a few for you: the optimum TWR at takeoff should be around 0.5-0.7. About 33% of your takeoff mass must be fuel (at least), and I usually budget about 400-500 LF units for the airbreathing climb, per RAPIER, with the rest being LFO mix. I only use RAPIERs, of course (they are the best by far, so why use anything else). And always remember that your upper limit of payload to LKO is up to ~50%, but 25% is much more doable with some aesthetics flair, or inefficiencies, or just plain margin. Small or big your design might be, those ratios will hold, so make sure to check the final numbers in your design, make a few divisions and multiplications if need be, and change things accordingly. You can't cheat physics! (I mean, you can, but it is cheating, and it's done with the cheat menu
)
And the other half of the equation are aerodynamics. This is more of a "how the game engine likes things" kind of thing, in order to be able to hit those 400m/s, with a TWR as low as 0.4 (but normally a bit more), to have that nice >25% payload ratio. But some simple rules will help a lot:
-Leave no open nodes. Front or back, that's important: no matter how it looks, if you have an open node somewhere, the game thinks that is a flat surface against the wind. The drag will be horrible.
-Also avoid unshielded surface-mounted stuff. These days, it pays to put everything inside cargo bays and/or fairings. You can check if a part is being shielded or not (and how much drag it gives) with the debug menu, by enabling the aerodynamic values to be displayed int he right-click menu. The arrow visualization tool is crappy, and will mislead you. This will teach you a lot, if you use it.
-Use just the intakes you need. Frontal surface is the main thing that will limit your drag, having more intakes than absolutely necessary will increase your drag without giving anything in return. One shock cone per two RAPIERs, or a single precooler per RAPIER, is more than enough. Yeah, the ideal designs usually turn out very, very long and skinny that way. That is why we end up going to Mk3, for the added diameter with the same frontal surface (after a few adapters).
-Mk2 fuselages are crappy. If you want to build Mk2, make sure your TWR is above 0.6, and that will hit your maximum payload, since you still have to be >25% fuel at takeoff, and you need proportionately more engine weight. The best drag/tankage ratios are the rocket parts, with Mk3 a close second. But Mk2 is still perfectly doable, of course, just with a lower payload fraction.
-Wings are necessary for flight, but dead weight in the climb to orbit. Less is more, but you have to have enough to take off when full and get to that level speed run at sea level. BigS wings are cool, because they double as LF reservoirs, and thus their mass hit is smaller (even though as fuel tank only, they are rather crappy).
Rune. Yup, that's pretty much it, the rest is just making it stable and capable of taking off, but that's airplane-building.
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My phone does weird things. Disregard! (And delete if appropiate).
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1 hour ago, tater said:
It single handedly made me stop watching the show. I tried last year, and saw something that annoyed me, and stopped. A friend likes the show, and I gave it another chance, only to see that utter nonsense. It wasn't dramatic license, it was awful. It's nice to see that the creator didn't like it, but they should have reshot it, frankly. Maybe next year I'll watch again. Probably not.
Well, sometimes you have to kind of switch off your rational brain a bit, else you would watch no shows. It's only once or twice per season...
Rune. At least The Expanse tries.
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On 8/4/2017 at 6:44 AM, tater said:
Just saw a couple minutes of the current (?) episode that involves some spacecraft maneuvering around Jupiter. Beyond absurd, had to change the channel. Adding RCS puffs to what are in effect X-wing type flying doesn't cut it. Note that I'm totally fine with space opera---but the closer to "now" it is, the less I can deal with that sort of stuff.
It also bothered me, because the same thing could have been presented just slightly differently, and work a million times better. Turns out, even the show's creators feel the same on this one. Check out how it should have been done.
Just like interstellar's suppossedly difficult axial docking. Just make it non-axial, stupid!
Rune. That one really stung.
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2 hours ago, Foxster said:
No, they aren't - or not stock anyway.
Even spaceplanes are marginal. You really need a rocket to punch up out of the soupy atmosphere quickly to lift even small payloads to orbit.
Actually...
No, seriously, Eve SSTO is a no-go. It is theoretically possible to do it, form the tallest mountain, with the efficientest spaceship, for some definitions of "SSTO" and "recoverable". Now, doing it in a practical way by the average kerbal? That is the impossible thing (without mods).
Rune. But it's a horse people like to beat down repeatedly.
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8 minutes ago, eloquentJane said:
I've encountered the Von Braun mission plan for Mars before, though not in detail. I chose this one mainly because it's the one that I've found the most detailed technical reports about, and because the versatility of the spacecraft design is interesting.
You can find it on astronautix, too, and I'm sure some google-fu will take you further: http://www.astronautix.com/v/vonbraunmarpedition-1969.html
Basically it's pretty much the same, minus the conical Earth return capsule, and with only three propulsion modules. I think that would scale much better for KSP. Everything is reused, too, which is a very nice touch. The lateral PPM's detach just short of Earth ejection, and the rest of the ship is light enough to do the Martian roundtrip, taking advantage of a Venus gravity assist, and capturing into a cheaper highly elliptical orbit at Mars.
Rune. I think the individual elements are actually the same design, just with a more sensible mission plan.
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You didn't ask for much, did you? The problem is, Laythe has a gravity well almost the size of Kerbin's, and Duna has no oxygen.And of course, forget about single-staging Eve. So, basically, what you need for this is a Kerbin-class chemical SSTO. And good luck squeezing that into a cargo bay! Here is one example of what you are looking at:
The first one is my Heinlein, and the second one the Lackluster. They have the particularity of needing no heatshield, since the can reenter either nose-first stably (and that shielded docking port is unbelievably tough), or switch to a tail first attitude with RCS on the high atmosphere, or airbrakes and chutes lower down. Took quite a lot of finagling to get cose-to-stable enough to do that, tough.
Edit: what do you know, I already had one that fits the bill. Pretty simple to reverse-engineer, no clipped parts at all, and the docking port is balanced on the other side with a fuel cell. 18 Parts, single seater, single spike. Thoroughly untested, but it has the numbers to have me pretty sure it'll do the job. Maybe with an additional parachute.
Rune. I've never needed a heatshield to return form low orbit.
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Pretty cool concept to try and recreate. I was myself very close to doing a full "Mars '69" mission at several points in the past. Have you checked that one out? It was a concept by Von Braun, similar to this one, but some orbital mechanics wizardry made all the nuclear stages come back to Earth to be reused. I also think IMLEO was considerably lower.
Rune. Very few things are new under the sun.
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3 hours ago, EpicSpaceTroll139 said:
Interesting, I've never had problems with autostruts on wings. What kind of phantom forces did you get?
Someone told me once that it was the tiny pulls to the right I was getting on my spaceplanes. Dunno if it was that 100%, but it stopped happening so much, so, you know, just in case. I also add a prayer to the FSM every now and then. can't hurt, right?
3 hours ago, Thor Wotansen said:So it seems the problem was with rigid attachment and not autostrut. I think the wings were trying to flex under extreme aerodynamic loads at 500m/s and with rigid attachment turned on, they couldn't flex and just broke off. I've used rigid attachment on a lot of wings but I haven't tried it on Big S wings before, I guess they don't like it so much, having a bit more drag and all.
Yeah, that is a bad idea. In general, if your structure is too rigid, KSP will usually blow it up. Glad you got things sorted out, tough!
1 hour ago, Azimech said:Autostrutting wings does not always invoke the kraken, I use it often but only on wing tips. That's fine until you damage your craft and somehow the rest goes into RUD.
Autostrutting to heaviest part has another risk because the code is too immature and will easily choose a fuel tank based on resource mass instead of empty mass. I've had a kraken attack when I used fuel beyond a certain level and the struts started switching during flight. This also means that if you dock with a space station with a heavier part it could summon the kraken anyway. I should write a bug report on this.
But it's true, often struts work better than autostruts. Too many struts creates problems as well, a structure that bends will break less easily (and keep your FPS higher).
Not a matter of blowing up, just weird forces applied. And yeah, I think we concur on the basics: use autostrutting as least as possible, only when it's necessary. I've saved so many space station at this point with a quick autostrut.
1 hour ago, Majorjim! said:Except it does when anything you dock to has a heavier part.
;-)
I've found it a bit less kraken-inducing than root part, but yeah, it still has some issues.
Rune. Protip: In case of "the shakes", freeze things by warping time, then start fiddling with autostruts until the shakes stop. Greatest trick ever.
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4 hours ago, Thor Wotansen said:
and everything is autostrutted to the root part, which is the cargo bay.
There's your problem. Autostrutting is far from a magic bullet, and if fact it can be counter-productive if you abuse it. Limit it to a few key parts several joints away, and never wings (don't ask me why, but that creates phantom forces). I'd just autostrut the engines and the adaptors on each end of the ship, and it would probably work like that.
Rune. Also, I always autrostrut to "heaviest part", because that doesn't suddenly change when you dock, often summoning the kraken.
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2 hours ago, Nibb31 said:
Yeah, well, we get new Mars DRMs every couple of years, I doubt that such a plan will stick.
That's 10 launches to construct two vehicles, plus at least half a dozen crewed launches to go with it. It's not realistic.
So we agree. The thing Gerstenmaier presented to the advisory council is, at most, a waste of good paper.
15 minutes ago, DerekL1963 said:ISS maintenance to date has been limited to routine preventative maintenance and occasional corrective maintenance (in the form of replacing LRU's). It's never had even a minor refit let alone serious systems level work of the nature that a Mars craft (which must operate for the better part of a decade without abort or escape capability) will require. (Especially after it's second of third trip when much of the machinery will be ageing.) In fact, the plan is that when it requires such a level of maintenance it will simply be disposed of. (Presuming it already hasn't been disposed of.)
And the Gateway at a minimum adds something a Mars craft will almost certainly not have - the ability to dock (or berth) the multiple spacecraft required to support all of that work. (ISS currently has a Soyuz and two Progress docked, not too long ago it had those plus a Dragon.)ISS has been operating for way more than a decade, without using its abort capability. Yes it had resupply, but so can this thing. Docking multiple ships is as simple as giving it more than one docking fixture (it should have at least two, but geometry says three probably makes the most sense). The gateway station, again, adds zero capability to this thing. Remember, we are talking a SEP tug+Habitat of around 40mT, with a ~10mT logistics module attached. More like a bigger Salyut with legs than anything else. So if it needs anything done to it that requires more than a docking, you might as well launch a new one.
That is what we are supposed to get at the end of all this, BTW. A ~50mT semi-used solar-electric Salyut, and a manned Mars flyby. Oh, and a ~40mT lunar station that mirrors its capabilities, but can't move. Now somebody get me a budget projection so I can work out how many 20~50mT dumb chemical stages we could lift for the same money.
Rune. And if I sound salty... well, it's not your fault, guys, so sorry.
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9 minutes ago, Nibb31 said:
The DSH *is* the Mars Transport Vehicle. It's the smallest possible habitation for 4 crew members that can sustain long duration manned flights in deep space. All it needs is the SEP tug and it becomes your ride to Mars.
So the plan is to build the DSH, send crews back and forth on Orion, and then attach a SEP tug module.
Not according to the slides I've seen. The plan is to assemble a ~40mT station out of 10mT modules co-manifested with Orion, and then launch a ~40mT separate DST with much bigger solar panels, attach a logistic module to it (also co-manifested with Orion flights, but far into the murky future, we are talking ~2027 here), and use that for anything interesting.
Rune. Unless you can point me to a more recent source than this?
Is this an SSTO to everywhere or not?
in KSP1 Discussion
Posted · Edited by Rune
Dude, you tamed Eve. And you did it using Rhinos! Mad math skillz there, many kudos deserved!
Rune. Not seeing nukes in there was the most disconcerting thing of it all.