MerlinsMaster
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Posts posted by MerlinsMaster
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Hey guys,
Is there a way to display alarms in the "actual time" as opposed to "how much time from the present"? I'm trying to get a transfer window back from Jool to Kerbin, and I don't want to have to add years and days to the current date to figure out what day I am arriving at Jool.
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I just watched Episode 1. Looks pretty good, but I just have two critiques:
One, you may need a small amount of dialogue or subtitles to clarify your narrative. For the first several minutes, I did not have a clear idea of what was happening.
Two, many of the shots are way too dark. There is a mod available that adds a small amount of ambient light to the game. You should check it out.
One additional suggestion: if you're not already using it, KerbCam is an excellent tool for creating professional looking cinematics.
Looking forward to your next episode.
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Dang, the value for Eloo capture in the wiki map is wrong, should be 210 m/s instead of 2100 m/s. I justed tested it with a "spare" rocket in Eloo orbit and getting away is pretty cheap. I think i will use your map in the future :-).
Yeah, it's a great map, the best one I've found so far. It's also nice because it shows you all the places where you can use aerobraking, which is pretty handy.
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Switching between the body buttons should not change your dv, only the TWR. KER shows always vaccum dv unless you activate the "Atmospheric stats" button.
Okay, I just clicked off Atmospheric Stats and now the delta v appears to be what it is when I launch the ship. Thanks, that's exactly what I needed.
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Switching between the body buttons should not change your dv, only the TWR. KER shows always vaccum dv unless you activate the "Atmospheric stats" button. And kfunk is right, you won't make it back with 7000 m/s. You might be able to safe 950 m/s on the return by slamming into Kerbins atmosphere, but you will still be ~500 m/s short. The cold equations win. Also the wiki cheat sheet is highly optimistic, i would add at least 10% margin to the theoretical value.
Here is the delta v map I use most often.
http://forum.kerbalspaceprogram.com/threads/41652-A-more-accurate-delta-v-map
Now reading this, I originally thought I'd need about 10km/s for the round trip and have a little bit of breathing room. But Metaphor and a few others told me that it won't take as much delta to return. Here's a link to that thread if you're interested: http://forum.kerbalspaceprogram.com/threads/88381-How-to-make-a-round-trip-HEAVY-reusable-interplanetary-rocket/page2
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Isp varies with atmospheric pressure. KSP does something a bit silly and alters fuel consumption rather than thrust, but it still means you need to consider the lower values for Kerbin, Eve, etc. The vacuum ÃŽâ€V should remain unchanged (And be the same for all airless bodies for the obvious reason), though TWR will be different for every body.
That was my thought, but there's no button for vacuum, and I'm pretty sure the buttons for different airless bodies have different values.
Also, 7 km/s from where? It might be enough from LKO, but is definitely not from the surface of Kerbin (unless you're doing some very clever flying)Yeah, I build my interplanetary ships in orbit, so it's 7000 from LKO.
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So I'm designing a spaceship to get to Eeloo, and I'm trying to create a design that has the required delta v (I'm figuring about 7000 to get there and back), but on this screen in Kerbal Engineer...
...there are different buttons for each planetary body, each having a different delta v estimate. Can anyone tell me what this means? If the estimate is one value when you press the Kerbin button, and is a different value when you press the Eeloo button, which one is the correct one?
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Does anyone know if the asteroids have any extractable resources on them? And if not, is there any way to edit the asteroids so that they do?
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Modular Kolonization System + Kethane let's you scan for water, but I don't know if the resource it finds is compatible with Interstellar. (I think it should be in theory, but I haven't confirmed personally)
Yeah. But right now I have crash fatigue and I'm trying to go a lightly modded as possible, and MK and Kethane are two pretty big ones.
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You made one slightly flawed assumption - that water was present everywhere on Minmus. It isn't.
If you want the cheat sheet, you can take a look at GameData\WarpPlugin\PlanetResourceData\minmus_water.png and the other pngs in that folder - they're the distribution maps for where you can find given resources, and their relative densities.
I currently have an ISRU on minmus and it is happily extracting water, and turning it into fuel for me, so the mechanics do work, it's just a matter of placement
Is there a way of scanning for water? Like with the ScanSat mod maybe?
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Is there a way to turn life support off when it's not in use? I have this mod called Cryocabin that provides a crew can that allows the Kerbals to go into cryosleep. This will allow me to just need life support for the month that the ship is at the planet, as opposed to needing it for the entire trip.
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Oh my, I really need to get around to updating these designs, but they should still work in the current sandbox version of the game.
You know, it was one of your other threads regarding this subject that made me want to do a reusable interplanetary rocket to begin with. I tried to reverse engineer one of them by examining the pictures, but didn't have a lot of luck. Now that I know that you've posted craft files, I will look at them and see how I can incorporate some of their aspects into my design.
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Looks like you're already well on your way, but in the future consider a Kerbin system ski lift approach. I have a fleet of tugs can be used to boost ships up to Kerbin escape velocity, then detach and swing around for refueling and orbital parking. The tugs can be docked together to increase deltav for the payload... a quick test showed that three tugs could provide 120t with between 2400 dv @ 1.7 TWR and 4700 dv @ .7 TWR.
http://i.imgur.com/Nd8PxYnl.png
Good luck on your mission!
That's a pretty cool idea. I'm definitely going to try to implement that somewhere.
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it was a very fast and simple build and i think i will redo it and create an actual working 120+ t eeloo orbit and return however i dont plan to go 100% reusable on that, thats overkill for me. it was a 100% vanilla build so i wont use these "nuclear generators", the solar panels was just for show and a bit for making it 125~ tons.
As well the thread seems to be [Answered], the OP splitted his ship or went with something like i have displayed. i think i could have increased dV by swapping engines for aerospike, but that would increase burn time.
Hey everybody,
I know it's been a few days, but I just wanted to let you know how it's going. Basically, what I did is I used Sudslv's approach as a starting point and modified it. It's true that connecting the tanks together radially with docking ports is not a good way to go, because if they're docked off angle by even a degree, the engines will be pointing in different directions. So instead, I docked all the engines to a docking assembly that makes up the front of the drive section. It turned out that I could also get ample delta with just five engines instead of nine.
While it didn't take me very long to build the entire thing in the VAB, I've spent all week launching the individual components and docking them together in orbit. Here is a pic just to give you a general idea, and I'll be posting an imgur album later on when I'm finished.
Right now there's a fuel tank where the command section is going to be. I'm in the middle of filling up all of those massive tanks. Once I do that, I will timewarp to the next available launch window for Eeloo, and fly the command section up with the crew. Once it's docked, they will set off for Eeloo.
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so i spent a bit of time calculating and experimenting.
i ended up building a massive interstellar ship which gives me 7.2k dV and probably someone like scott manley could make Eeloo land and return 100% reusable.
to assemble it in LKO it requires 7 launches (can be less). i would never suggest to do single mission for such a massive payload. split it up 3-4x.
Wow! That's impressive! I'm amazed you got the delta v that high with so little fuel. I can't wait to try this out. Thanks!
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What you're looking for is delta-v. The amount of delta-v to Eeloo remains constant for your given Hohmann transfer; you need as much to get a 20 ton payload to Eeloo as you do for a 120 ton one. It's just much harder to get that delta-v with the 120 ton payload, because you're pushing a lot more. But there's actually a way to reduce the overall amount of delta-v needed to get places. You've stated you basically want to do a simple Hohmann transfer with a mid-course correction, but for something that size, you may want to look into gravity assists. That's a big-bad phrase around here, even for some of the more experienced users, but they're honestly not all that difficult. Allmhuran has aexplaining how they work, but getting them to line up in space and time can be tricky. There's a few tools out there to help you get timing right, like this one or this one that's specifically oriented towards finding flyby series. Again, these programs look daunting, but they're relatively easy to read and use once you've looked them over. On the topic of cutting delta-v, as others have mentioned, aerocapture at Kerbin on the return trip is going to save you a lot and won't take hardly any delta-v from Eeloo's altitude.
I'll definitely check those out. Even on the off chance I don't end up needing them for this, they will really come in handy when I try to do a grand tour mission.
You say that 120 tons is set in stone. Is it? You'd likely be able to cut a significant amount of delta-v off the return trip if you ditch those landers and rovers. Why would you want to bring the rovers back anyways? Besides, Eeloo landers need to be little more than Mün landers, which should be cheaply and easily replaceable once you've returned to Kerbin's SOI. You might also consider ditching the command section once you're ready to return, if you know you have enough delta-v (I'll get to how to know that now).Those landers and rovers are going to be left there, but they're not a huge portion of the payload. As for the command section, that would be basically breaking the ship apart. I might as well have stages if I do that.
Getting 120 tons to Eeloo, and back, would be a significant challenge even for some of the best players. Take a look at the staging article on the KSP wiki if you're not sure how serial/parallel/asparagus staging works. Cut your ship design down as much as you can. Something that might be very helpful for you would be Kerbal Engineering Redux, a mod that tells you exactly how much delta-v you have to start out with in the VAB, and gives you a bunch more information in flight, including your sea-level and ground-reference altitude to a body, remaining delta-v in your rocket, remaining burn time, and much more. Mechjeb does something similar, but also has some nice autopilot features for your rovers and the transfer burns to and from Eeloo. If you decide to go with a basic Hohmann transfer, Olexander Savchuk has a wonderful site that gives you a graphical representation of burn positions, http://ksp.olex.biz/. Alternatively, Alex Moon has a more number-y site that'll tell you an exact time and date that you should leave on to get the best possible transfer, as well as letting you pick earlier or later launch dates and slower or faster transfers.Oh, trust me, I don't go anywhere without KER and Mechjeb. I don't know what I'd do without them. As for olex.biz, I've had it bookmarked for a while now, but haven't had a chance to really get into it yet.
I wish you the best of luck in this very Kerbal venture. Consider posting your progress in a thread Mission Reports in an Imgur album, or make some videos and post them in the Live From Mission Control subforum. I'm sure there's many users, including myself, that would like to see this pulled off.Welcome to the forums.
Thanks! The pointers and advice that everyone here has given me has got me pretty energized. I can't wait to start implementing them and posting the results afterwards.
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I'd definitely consider at least a few drop tanks if you're having that much trouble ... toss a controller on, a few solar panels, and a couple of separatrons, drop the first few tanks before you hit Kerbin SoI and just deorbit them. Enjoy the "free" fuel, that should get you around 800 extra delta-v (more if you're willing to clutter things up)
That's not a bad idea. I'll keep that in mind.
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It's probably not what you want to hear, but I think the best advice is to reconsider your design strategy. It doesn't need to be totally reusable (rockets and be staged, and parts can be left on Eeloo), it doesn't need to be all sent together, and there are engines you're choosing not to use.
Well, total reuseability is my primary goal with this particular mission. I chose Eeloo because it's one of the harder places to get to. And if it's true that I can do it with 6000 delta v, then I think I can do it.
But I'm not ruling out any types of engines. Which ones were you thinking of?
Breaking up the payload could help, instead of sending 120t all at once. I usually send mission payloads for interplanetary missions in parts, e.g. for my last Duna mission, I sent the surface base & rover on one rocket, a station, return fuel, and lander on a second rocket, and then crew and science on a third, modular vessel (parts went up on separate rockets). Breaking the payload up into sections makes design and flying the mission much easier than a monolithic payload.Actually, and I see how this will seem ridiculous, but I'm already sending stuff (larger rovers and hab modules) like that ahead of the manned ship. The landers and rovers on the ship are primarily in case that other stuff didn't make it. It's a big mission, but I 'm finding it to be a fun challenge. If it turns out I can't do it, that's fine. But I'm going to give it the old college try first.
Staging and drop tanks can also increase your dV for a similar payload fraction.This is going to sound like a dumb question, but what are drop tanks?
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Remember that you need far less energy to leave Eeloo SoI than to leave Kerbin SoI and that , given that Eeloo is much further away from Sol than Kerbin, you have far less velocity change to slow down enough to get to Kerbin orbit than the oposite way ( in the same way you need 900 ish dV to get to Minmus from LKO, but only need 200-300 dV to get back ). More, remember that it is assumed that you will aerobrake in Kerbin return
I did not know that. Live and learn.
I know it well. But so far I've been more likely to just check out one of the delta v maps instead, because I'm still having trouble wrapping my head around porkchop plots. But I'll keep at it anyway.
If you plan well and are willing to wait for the ultimate best windows to get there and to get back you can do the whole trip for less than 5000 dV, but as a rough sketch, the numbers metaphor gives are correct ... You definitely don't need 10k dV, 6k should be enough.Well, that should make it a bit easier.
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The delta-V for a trip is symmetric, the same outbound as return, but it's how you provide that delta-V that introduces the asymmetry. On the return trip you can capture into LKO using drag from Kerbin's atmosphere, meaning you don't need to use your engines for that.
Yeah, I plan on aerobraking wherever possible, but I don't want to have to depend on that. I'd rather have more than I need, that way I'm not screwed if the aerobraking goes badly.
And if you'd rather not use the LV-N, try the KR-2L. One should be more than enough thrust, and the superlative TWR may reduce your dry mass compared to a bunch of LV-909's or aerospikes.Hmm...I never thought of using one of those in space, figured it be way too heavy. But if I just need one, that could work.
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In real life the NERVA engine was to have had scrubbers to remove fission products (see http://www.osti.gov/scitech/servlets/purl/4510638) but Kerbals being Kerbals would probably never bother with such nonsense. Besides, given the daily radiation doses experienced by Kerbals in their jobs, they're probably not overly sensitive to radiation anyway.
Interesting. On the other hand, I've spent some time on the
Atomic Rockets website reading about how a nuclear spaceship has to be designed in a shape that tapers inward toward the engine so it doesn't fall outside of the engine radiation shield's shadow.
As I understood it, it was basically talking about nuclear thermal rockets in general, not specifically the NERVA, although the NERVA does fall under that catagory.
I wonder how effective those scrubbers would be. I don't know if I'd trust that they were.
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My first manned return mission to Duna, which used a rocket that I designed through trial and error, had 700+ parts, weighed roughly 1.5 kilotons and needed to be refuelled twice. I used the TRE and managed to do it with a 210t rocket with 89 parts and I didn't need to refuel it at all. What's everyone's problem with Tsiolkovsky?
Any chance you could post those? I'm trying to build a large interplanetary ship and it would be really educational to see what you did to get that improvement.
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if you don't have my LV-N aversion (I'm not actually anti-nuke; I used to work at a reactor. I just think they're a bit unbalanced in-game; they make long trips too easy), then the nukes are certainly the way to go. Again, a single engine is most efficient, but would be painfully slow.
The limitation isn't anything in-game; the limiting factor is how long you're willing to sit there watching a burn happen.
For story purposes, I'm restricting myself from using nukes in LKO, as they are extremely radioactive (although there are no ingame effects), and always planned on having couple conventional engines to get me out of that area before engaging the LV-Ns.
As far as running on a single engine, I would prefer not to have to do numerous phased burns, as that would be needlessly complicated and there are only so many hours in the day. I really want to just make a burn at the beginning, a mid course correction half way there, and then a burn at the end.
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You shouldn't need 10,000 m/s of delta-v to get from Kerbin orbit to Eeloo orbit and back. It should only take about 2000 to leave + 500 for plane change + 1500 for capture, and another 1500 to get back, or 5500 total (6000 with contingency). If you use LV-Ns, a 120-ton payload can be pushed by a 240-ton stage (something like 6 orange tanks and 12 LV-Ns, to keep burn times reasonable). If you leave most of your payload at Eeloo, you can get by with less.
Are you saying that I need 4000 to get out there, but only 1500 to get back? If so, how does that work?
What's the best way to determine interplanetary launch windows?
in KSP1 Gameplay Questions and Tutorials
Posted · Edited by MerlinsMaster
Yeah, yeah, yeah, I know...ksp.olex.biz. But here's the problem. Olex tells me one thing. MechJeb tells me another. Kerbal Alarm Clock tells me something else. Alex Moon tells me...I think you all know where I'm going with this. Does anyone know if one is better than another, or is it just a matter of preference?
Also, a question for all of you that use Kerbal Alarm Clock. Let's say I've just set an alarm for a Kerbin to Jool launch window. Now I want to set an alarm for a return launch window. At the risk of stating the obvious, the departure date for the return needs to be AFTER I get to Jool. The problem is, the alarms tell you how much time UNTIL the alarm goes off, as opposed to the actual time. This makes it very difficult to figure out when I will arrive at Jool, because I'm forced to add the time left on the alarm to the current time to get this figure, which involves finding out how many days in a Kerbin year there are and that is a huge pain in the asteroid. Is there ANY way to change this so that it tells you the ACTUAL TIME?