[1.2] Real Solar System v12.0 Dec 8

[Lilienthal]

One's orbit is determined by it's mission. GPS sats are set to provide min coverage of x number of sat seen at anyplace/anytime. Sun Sync orbits are used a lot for earth observation, geo sync orbits to put them in a stationary place as observed from earth and provide coverage to a certain area of the earth.

True. Not really what I wanted to know ;-). But maybe I should have been clearer, so 2nd try. --

My understanding is that for interplanetary travel, it makes sense to start from a low Earth orbit that is in the same plane as the ecliptic. However, I found sofar no tool that really helps me to determine when I am in that plane. - With an orbit in a lunar plane, I can just set the moon as a target and then use the standard AN/DN points to adjust my orbit to precisely match the plane of the moon's orbit. I tried to describe that in the RSS wiki, as I thought it might help others to reach the moon with less delta v.

However, and that was the intention of my question, I don't know how to align an low earth orbit plane with the ecliptic and was wondering if someone has a cool idea.

My ideas so far:

+ look for a point where the sun is in zenith, the spacecraft at latitude 0 and the inclination at 23.44 degrees. (very imprecise)

+ look at the save file and calculate the desired plane change. (complicated and not really telling me what to do exactly)

+ hyperedit a craft on an orbit on the ecliptical plane and match to this. (cheating.)

+ just go for an orbit on the lunar plane. (very, very imprecise)

Any better ideas?

Thanks!

[Hattivat]

+ just go for an orbit on the lunar plane. (very, very imprecise)

This is what I do most of the time, works well enough to send a probe on its merry way to Saturn. Wouldn't call it "very, very imprecise".

That being said, doesn't it actually depend on the mission? I mean, my understanding is that having an initial orbit tilted somewhat from the ecliptic is basically a cheap way to achieve plane change when you aim at something that is not on the same plane as Earth.

[Woopert]

Hi, I'm not sure if I did it right, but I edited the Pluto map to give it a more accurate color (from what we know, at least ) and more contrast. I took a SpaceEngine exported map of Pluto, used the Average filter in Photoshop, and used that color to make a new layer over the current map. I set the blend mode to Color to keep the brightness, then I applied a Levels adjustment layer set to "Auto" which ended up doing a nice job with the contrast. Feel free to use it if you like it or if I did it correctly (to NathanKell and SpacedInvader).

Link: https://dl.dropboxusercontent.com/u/86765036/PlutoColor.zip

Preview:

Edited September 21, 2014 by Woopert

[camlost]

I found that it's not possible to land a plane outside the space center. The landing gears would sink into the ground and the plane explodes. Landing is only possible within a few km from the space center. This happens at any space center location. I was using 4096x heightmap. Strangely, this doesn't happen with a rover

[ThorBeorn]

I found that it's not possible to land a plane outside the space center. The landing gears would sink into the ground and the plane explodes. Landing is only possible within a few km from the space center. This happens at any space center location. I was using 4096x heightmap. Strangely, this doesn't happen with a rover

I've seen other people report this. It happens to me too. I think NathanKell knows about this.

I seems to happen no matter how gently (low vertical speed) you put your plane down. Have you tried a VTOL landing?

[metaphor]

I noticed that FAR's values for the atmospheric properties of other planets was based on the stock planets. So I changed the FAR config file to work with the RSS planets (Laythe = Titan, Dres = Saturn, etc) to give more realistic atmospheric properties. Here is the file, just extract into KSP folder if you want to try it.

[beamthegreat]

Hi I have installed the RSS mod for the first time and I found that there is a severe lack of fuel tanks in this mod and the parts do not match with each other.

For example, if I use a 3m capsule I have to connect it with a 4m fuel tank and a 2.5m engine for my upperstage since its the closest component in size. Can someone confirm whether this is normal? I have installed all the required mod.

Also, I decided to install KW rocketry and procedural parts because of this but every time I do that, my game crashes upon loading. Without it, the RSS mod works perfectly fine.

Thanks.

[Hattivat]

Hi I have installed the RSS mod for the first time and I found that there is a severe lack of fuel tanks in this mod and the parts do not match with each other.

For example, if I use a 3m capsule I have to connect it with a 4m fuel tank and a 2.5m engine for my upperstage since its the closest component in size. Can someone confirm whether this is normal? I have installed all the required mod.

Also, I decided to install KW rocketry and procedural parts because of this but every time I do that, my game crashes upon loading. Without it, the RSS mod works perfectly fine.

Thanks.

The part sizes are not modified by RSS, they are modified by the Realism Overhaul mod. Thus, you are asking in the wrong thread.

Now, as far as Realism Overhaul is concerned, yes, these sizes are normal. "Severe lack of fuel tanks" is due to the fact that precisely adjusting the dimensions of fuel tanks is one of the most important tools for building successful rockets with all the realism-increasing mods (since most engines don't throttle, you need your tanks to be exactly the right size), so fuel tanks of pre-defined size are not very useful. For this reason, as you already deduced, most people use procedural parts for this purpose.

Overall, parts in Realism Overhaul have realistic sizes, so the 3 man pod is 4 meters wide, because that's how wide the Apollo capsule was. Engines also have roughly real-life dimensions, so they are often narrower than the tanks above them (as they are in real life, look up pictures of Saturn V for reference). Given how stock interstages work, this is a slight problem, but one that is easy to mitigate by using procedural interstages (procedural fairings mod has this option). I never tried using them, but the interstage parts from KW rocketry might work too.

Without logs we can't be sure why your game crashes, but the most likely culprit is that your game is running out of memory. The solution is either to install lower-resolution textures for RSS or to install the Active Texture Management mod.

[Kitspace]

Hello

While mods are getting more and more realistic quite quickly one problem is becoming more and more important to solve.

Also I seem to be one of the few who still do not know how to do this properly.

How do you launch your rockets in a single continuous burn like it is done in real life without coasting and waiting?

What is the trick here? How to keep my apoapsis just go somewhere in front of me neither running half an orbit further away nor letting me pass over it and start falling back? What if I am unable to do so for some reason? What should my pitch attitude in relation to the prograde direction be when out of atmosphere? Should I aim at the prograde at apoapsis instead of the prograde at my current location at some point? How to do an efficient gravity assisted turn while still aiming for a certain altitude at the end or at least knowing from the beginning what it would be? What I am trying to do is to precisely tune mechjeb for that kind of a launch but it seems to hate and resist skipping the coasting part at all costs while loving to flip the rocket in the dense atmosphere spoiling half of the launches and that is really very very very annoying.

That is certainly not a good reliable way of doing things. Also there is pretty much nothing to read. Everything that is availible around always says push throttle hard fly up then fly right then coast and circularize. What can I do with it?

It kind of spoils the experience badly.

Thank you!

[Hattivat]

The guidelines below are obviously only one of many options, but they are pretty foolproof and work perfectly for me.

Design your rocket to have about 1.2 TWR at sea level, this way you should stay close to terminal velocity but never exceed it, without having to throttle.

Fly straight up until your rocket accelerates to 100 m/s, then start turning very gradually. If you do the tiny initial turn just right (comes with experience) you should be able to execute the whole orbital launch by simply keeping your rocket pointed at the prograde vector the whole time. Your turn should reach 1/4 of the way at around 10 km of altitude and half the way (45 degrees) at around 30 km of altitude.

As for Mechjeb, I don't use it for launches, so can't help with that.

[Starwaster]

Kitspace, make sure you have the latest dev version. It has a limit angle of attack feature in the launch autopilot. Set it to 5 degrees.

[Kitspace]

Thank you.

However it is one of the ways to deal with rockets that are flipping over.

The previous post is a general technique of making a turn. It does not help me with aiming a certain target orbit or controlling where the rocket is going. Neither does it help me avoiding circularization as a separate ignition burn with engines that are only capable of one ignition. What thrust to weight ratio and longitudinal acceleration should a rocket stage have near burnout high up in space? And what about in average through the flight? What attitude should I aim at? What are there real life numbers here? Where can I read something more particular on this? Everything around is either way too simple and basic or it assumes that the reader is already capable of doing this. Where is the reader supposed to learn how to do this properly just without simplifications for the first time? Why is this thing so unpopular to discuss in the scope of the game and its tutorials and stuff? Are there any mods or other programs that can calculate or optimize the rocket launch the way it is supposed to be normally? Maybe give a pitch program as a function of time or speed for example for the rocket to follow?

Edited September 22, 2014 by Kitspace

[Hattivat]

The turn altitudes I've described above are for a 200 km circular orbit. I normally design my rockets in such a way that the first two stages get me into low orbit, and then a third stage lets me transfer to a different orbit if that is my aim. That's how most of real-life rockets are designed as well AFAIK.

"controlling where the rocket is going" - that's what gimbals are for. Aside from the initial "nudge" to start the gravity turn, you basically keep pointing prograde all the time. Once you get above the thick part of the atmosphere, you are free to point further away from the prograde vector (e.g. if you need it to correct your inclination or keep your apoapsis before you).

"Neither does it help me avoiding circularization as a separate ignition burn with engines that are only capable of one ignition" - if you design your rocket with correct TWR and follow the trajectory I described previously, there should be no coasting whatsoever in your launch.

"What thrust to weight ratio and longitudinal acceleration should a rocket stage have near burnout high up in space" - many different designs possible, but my guidelines for stages in a purely vertical (Saturn-style) rocket would be:

Stage I 4500 m/s delta-v, initial TWR 1.2, final TWR less than 5

Stage II 5000 m/s delta-v, initial TWR 0.9, final TWR less than 5

Stage III ...... delta-v (depends on the mission), initial TWR 0.5, final TWR depends

First stage burnout at about 2.5 km/s orbital speed, altitude about 100 km, attitude close to but not completely horizontal

[Kitspace]

Close to but not completely horizontal? Do you mean aiming higher or lower? I generally run over the apoapsis and fall back into the atmosphere or the apoapsis goes further and further away from me until the orbit just starts to become highly elliptic quickly. How to correct these conditions properly? How to prevent the apoapsis from raising higher than it is supposed to be until the rocket gains enough speed for the periapsis to appear for the first time above the ground?

[Hattivat]

I mean aiming slightly higher, that's how I usually end up aiming at this stage. Generally with the second stage you need to look at the "time to apoapsis" reading once in a while, if it gets close to zero (like under 20 s), you need to pitch as far up as it takes to stop it from going further down. When it starts going up again, you can gradually start pitching down (ie. turning horizontal) again, until it starts going down again. The ideal you are aiming for is time to apoapsis constantly, but very slowly, falling, and approaching zero exactly when you run out of fuel.

Preventing the apoapsis from raising too high - that's harder, especially initially, before you develop an instinctual understanding of the whole process. Generally the opposite of the above - watch the "time to apoapsis" (and the apoapsis reading itself), and if it starts rising too fast, turn more horizontal. Towards the very end of the burn you might have to pitch down to sligthly below the prograde vector in order to keep the orbit circular, that's perfectly OK.

It should also be mentioned that generally it is perfectly OK to finish you burn behind the apoapsis. It's just that it requires very good timing to get right, so I generally prefer to keep my apoapsis in front of me and I recommend you do the same, at least initially.

[ZaPPPa]

I have come up with a launch strategy that works quite well for me and is able to turn into a low orbit (120km) if need be. This method requires FAR to be installed. Also, this uses the RftS engine config, which does not have vector thrust for most engines, therefore it is harder to control the rocket without lots of SAS and RCS.

I create my rocket out of balance on purpose, shifting weight and drag ever so slightly towards the turn I want to make. I normally do this by attaching a radial chute to the main stage. Then I attach some small steerable fins and tweak them to 5 degrees max. Finally I install enough RCS up top and at the bottom to combat the tip-over.

At launch I enable RCS and SAS to keep the rocket straight. It does not have enough vertical speed yet for the tail fins to keep it stable with the off-balance weight and drag, so RCS takes care of it. Once I reach 100m/s I disable RCS and let the rocket slowly make its turn by itself. After hitting 400m/s the SAS will start to wobble the rocket, so I turn it off and launch completely unguided. Every now and then, when the speed vector shifts a couple of degrees, I nudge the the rocket towards it so the attitude and speed vector are identical.

At around 30-40km I enable RCS. At around 50km it gets tricky. I try to match the attitude angle to the altitude (50 degrees at 50km), but have to be careful not to tip the rocket. I tend to overdo it on RCS now, because I have learned that a smooth launch is worth the extra weight. Also, lots of RCS on the first stage has little effect on total DeltaV.

I generally lose the main stage between 70km and 100km and am generally at between 70 and 80 degrees attitude. I then work with the second stage to tweak the final launch angle and target altitude. I like to stay between 60 and 30 seconds in front of Apoapsis for the duration of the launch.

Edited September 23, 2014 by ZaPPPa
Added RftS requirement

[Hattivat]

After a bit of searching through my folders I've found an uncut recording of a full launch sequence and uploaded it to youtube. I don't claim it to be perfect, but it should be pretty instructional for players new to the whole RSS/RO thing. It's my fully hydrolox super-heavy launch vehicle Veles II launching a 350 t surface habitat + transfer stage for a mission to Mars. Be warned: this is uncut and unabridged for maximum demonstrational value, and therefore boring to watch.

[MaxP]

Nope, it's rbray's ground-up rewrite of EVE. I.e. an overhaul of it.

It just happens to work a lot better with RSS than 7.x did.

I've found that EVE 7.4 looks much better than 9.2 Overhaul. With the last one, the earth texture is very dark, ant it's much more contrast sky.

And both of versions works fine without BoulderCo folder.

[Motokid600]

Other then installing EVE what can one do to pretty up RSS to the best possible quality?

Astonomer

Proot

TheSonicGalaxy

What is the status of these packs and RSS compatibility?

And besides texture quality, is there a way to make the now scaled up planets have more terrain features so to speak?

[MaxP]

is there a way to make the now scaled up planets have more terrain features so to speak?

Dreaming all the time...

[Starwaster]

Other then installing EVE what can one do to pretty up RSS to the best possible quality?

Astonomer

Proot

TheSonicGalaxy

What is the status of these packs and RSS compatibility?

And besides texture quality, is there a way to make the now scaled up planets have more terrain features so to speak?

Yes, it's been talked about quite a bit both in this forum thread and there's some information in the wiki. The wiki link is on the front page, first post.

Various posts in this thread discuss editing actual parameters for the various planets to increase their terrain resolution and/or detail. (and including the use of increased resolution height field maps for RL planets such as Mars and Earth). I don't have links to those discussions handy so you'll have to search for them yourself. Try terms heightfield and PQS

[NathanKell]

metaphor: dang, thought we fixed that. I know ferram wrote an atmosphere patch for RSS, but it must only change the (forthcoming) DRE atmosphere data, not the FAR data. Thanks!

camlost, ThorBeorn: thanks for the report. I will check when I get home. It *used* to work, so I'm unsure what's broken.

MaxP: If you remove the BoulderCo folder, you have removed all the cloud textures. So I would not recommend doing that.

Motokid600: This is an EVE config designed for RSS.

I also plan to look into what was done to improve the terrain in 6.4x Kerbol, and do it for RSS.

Hattivat: those are truly excellent helpful posts! Thanks!

Kitspace: You might want to look at the RSS wiki, linked in the OP. It has two tutorials from Ferram, one for building a rocket and one for flying it, and one from me regarding using MechJeb to fly ascents.

Many modern rockets *do* finish their burn after their original apogee; it's not uncommon or bad. Likely your upper stage(s) has too much thrust. A TWR that starts at 0.9 (vacuum TWR) is a *high* thrust upper stage. Centaur on Atlas V has more like a 0.4 TWR (maybe even 0.3). I don't recommend that for LEO--Atlas V is optimized for GTO missions--but it gives you an idea.

If you're launching a traditional 2-stage LV, then you want to use the first stage to establish the correct apogee--200km for a parking orbit, higher for longterm LEO orbiting--and burn the second stage to establish orbital velocity at or after that apogee. The best way to do that is to make your second stage's burn time around a minute longer than what "time to apoapsis" is when you start firing it, and burn it more or less completely horizontal, only burning +pitch when time-to-apoapsis goes below 20 seconds or so as Hattivat says.

[Kitspace]

Thank you everybody for your very patient support!

So as far as I got it it is normal to run over apoapsis while still running the engines and to keep flying you need to pitch higher than prograde. Right? But that is all about the mild modern rockets and what about the old classic ones that could give some very good gees even on the upper stages? How to keep the apoapsis from running away from me? The Titan had a place in the pitch program where it had to pitch down until the ascent vertical speed came to zero and only then thrust horizontally again as far as I know. Do I need to keep my apoapsis steady where it is supposed to be and let me come up to it or at least keep it somewhere? And should it still start to run away and rise quickly how to stop it? What if it rises way too quickly too complete the gravity turn and go below horizon and catch it before it reaches the required altitude maybe it even happens in atmosphere?

[Kitspace]

Also I have read the tutorials in the wiki more than once but they do not answer some of my questions that are quite essential for me understand what is wrong.

It is like when a real life rocket is doing this again and again in Orbiter it looks nice and it works but when I am doing the same thing it looks much the same but it does not work at all.

I have successfully tuned my mechjeb to make it look very much a like a real life launch and minimie the remaining required speed but never managed to eliminate the coasting part it loves so much and then of course it is all completely screwed up with a tiny little change in payload or something.

[Hattivat]

Thanks Nathan, your praise means a lot.

@Kitspace: Ah, so you want to pilot a historical rocket, that's a different story. In this case you cannot adjust the rocket to fit the most comfortable ascent path, you have to adjust the ascent path to fit the rocket (truism, I know, but it has to be said for clarity). It's probably also worth pointing out that launching to space on repurposed ICBMs is hard, and was hard in real life - it's one of the reasons why early satellites had such pronouncedly elliptical orbits and abysmal success rates.

For me most of the fun comes from designing my hardware, so I'm not too much into piloting replicas, but I think I can help you with some suggestions:

1. Generally the higher the TWR (initial and/or final) of the first stage (and the more delta-v it has) the flatter your trajectory should be.

2. If your flight plan includes a transition between a stage with high final TWR and a stage with low initial TWR, you probably need to pitch down (even as far as fully horizontal in some cases) some time before staging (so that your high final TWR doesn't rise your apoapsis too far), and pitch up after it (so that your time to apoapsis doesn't fall too fast with the low TWR of the other stage).

3. There is also the option of using your first stage to establish an apoapsis quickly (like Nathan described above) and coasting for some time between MECO and second stage ignition. In this case, you should probably include solid rocket ullage motors in your second stage design.

"What if it rises way too quickly too complete the gravity turn and go below horizon and catch it before it reaches the required altitude maybe it even happens in atmosphere?"

Well, I'm afraid that is a "you will not go to space today" moment. In this case you hit "revert to launch" and fly a flatter trajectory next time.