[1.2] Real Solar System v12.0 Dec 8

[NathanKell]

Well, it's scaling correctly but messing up lighting. Argh.

[NathanKell]

And another, finally-I-believe-it-works prerelease.

https://www.dropbox.com/s/3gg3jbkqqnhgc86/RealSolarSystem_v6.2pre4.zip

[MAKC]

And another, finally-I-believe-it-works prerelease.

https://www.dropbox.com/s/3gg3jbkqqnhgc86/RealSolarSystem_v6.2pre4.zip

Testing RN.

[SpacedInvader]

Lower twr upper stage. You want your stage to last a good minute or two more than your "time to apogee" at ignition (and burn at zero pitch). That may mean you circularize after apogee of course, but it gives you better control without relights.

Also make sure you ascend such that your apogee is where you want your final perigee to be, since that's what it will become.

How low should I take the TWR? Here is my current mission's launch vehicle:

Javascript is disabled. View full album

Yes, I know its obscenely long and skinny, I have a bad habit of designing top down, and then ending up with long skinny upper stages and then long fat lower stages. But anyway, you can see in the first shot that my circularization stage (#10) has a TWR of 1.14, how much lower would I take this? In the second picture, which is taken a few seconds after staging, you can see that my TTA is about 1.5 mins, while my stage is about double that, is this too short still? In the final two pictures, you can see what I mean when I'm having difficulty controlling the final shape of the orbit... with 15s to go on the stage, I've got the 275km apogee that I want as my perigee, but by the time I've burnt out that stage, my apogee is 2.2Mm, and my perigee isn't even 200km.

EDIT: I should also point out that I just set MJ to hold 90° at 0° pitch for this where normally I would spend some effort burning down or up to exert some control, though that usually ends up with a lower apogee and perigee. Also, I should point out that what I really want is for this stage to burn out with apogee around 275km and perigee around 40km-50km so that I've got very minimal burn left to circularize, but at the same time, the previous stage will burn up instead of becoming orbiting debris.

Edited May 27, 2014 by SpacedInvader

[BananaSplit]

Thank you so much! I'm sorry I haven't answered your post (because the forums were down). BTW thank you Nathan Kell for answering my message

[manni01]

I have a small problem. When I use this mod, the VAB, launchpad, runway, etc. stays at its original location (meaning the Launchpad is underground which results in big explosions when trying to launch rockets). It has nothing to do with the mods I'm using, I've tried a fresh file. I've tried looking at the configs but that doesn't do anything that helps solve my problem(the closest I've gotten is to be able to change coordinates of non-usable Launchpads, basically static objects that don't have anything to do with my problem). I'm using 0.23 ultimately for remote tech compatibility. All I really need is a download for a RSS version which is meant for 0.23, not 0.23.5. Please helps someone

[NathanKell]

SpacedInvader: whoops, forum outage.

1.14 is *very* high. Consider actual rockets from real life: Atlas's SEC has a starting TWR of like 0.3! That's low for LEO but fine for GTO. Most start at about0.5 to 0.7 or so. Even something with an abnormally high upper stage TWR, like Titan II, is only 0.9 or so.

If you want to keep using a stage with that high a TWR, you'll lose a bit of efficiency, but you still can. Just...don't engage it immediately after staging away your boost stage. Wait until time to apogee hits about a minute less than your stage runtime. Basically, ideally you want your stage to burn out precisely at apogee, but recall that burning even horizontal will extend time to apogee, so you want to start burning when there's more stage time remaining than time to apogee remaining.

manni01: Try the FAQ in the wiki, linked in first post.

[Armchair Rocket Scientist]

SpacedInvader: whoops, forum outage.

1.14 is *very* high. Consider actual rockets from real life: Atlas's SEC has a starting TWR of like 0.3! That's low for LEO but fine for GTO. Most start at about0.5 to 0.7 or so. Even something with an abnormally high upper stage TWR, like Titan II, is only 0.9 or so.

If you want to keep using a stage with that high a TWR, you'll lose a bit of efficiency, but you still can. Just...don't engage it immediately after staging away your boost stage. Wait until time to apogee hits about a minute less than your stage runtime. Basically, ideally you want your stage to burn out precisely at apogee, but recall that burning even horizontal will extend time to apogee, so you want to start burning when there's more stage time remaining than time to apogee remaining.

manni01: Try the FAQ in the wiki, linked in first post.

The 0.5-0.7 seems to only apply to liquid-fueled upper stages.

Antares appears to start with a TWR of 1.3 on the upper stage.

Scout's final stage has an absolutely ridiculous TWR. Like, at least 5.

[NathanKell]

Well. There is a class of solid meant to be fired *at* apogee, like Juno's cluster of Baby Sergeants. Final TWR about 50 on those.

[SpacedInvader]

SpacedInvader: whoops, forum outage.

1.14 is *very* high. Consider actual rockets from real life: Atlas's SEC has a starting TWR of like 0.3! That's low for LEO but fine for GTO. Most start at about0.5 to 0.7 or so. Even something with an abnormally high upper stage TWR, like Titan II, is only 0.9 or so.

If you want to keep using a stage with that high a TWR, you'll lose a bit of efficiency, but you still can. Just...don't engage it immediately after staging away your boost stage. Wait until time to apogee hits about a minute less than your stage runtime. Basically, ideally you want your stage to burn out precisely at apogee, but recall that burning even horizontal will extend time to apogee, so you want to start burning when there's more stage time remaining than time to apogee remaining.

manni01: Try the FAQ in the wiki, linked in first post.

The 0.5-0.7 seems to only apply to liquid-fueled upper stages.

Antares appears to start with a TWR of 1.3 on the upper stage.

Scout's final stage has an absolutely ridiculous TWR. Like, at least 5.

Well. There is a class of solid meant to be fired *at* apogee, like Juno's cluster of Baby Sergeants. Final TWR about 50 on those.

Looks like I've been *way* overbuilding my rockets all this time. 1.14 is about the lowest upper stage I've used to date and its usually carrying something around 2. I'm currently rebooting that entire mission because I didn't give my descent stage enough delta-v to land, so it became an impactor, so I'll aim for something like 0.5 - 0.7, but I will say that my experience with low upper stage TWR has been extremely low, if at all, ciruclarization. I guess this is where I ask, if I have my apogee at 275km, but then circularize some time after that, wouldn't that lead to me circularizing at a lower altitude than I want? Do I need to shoot for a higher initial apogee in this case?

[pingopete]

Hey nathan, just trying out 6.2r4 (or whatever is the latest one) and am running into a few issues, mainly the oceans are grey where not in direct sun light in map view and in game world, this happens regardless of trying to run EVE or not.

I can't get Overhaul 9 to function at all with this version. I appreciate both are dev versions atm, but just thought I'd say.

Also is the new system of launch site selection from the TC meant to be implemented? I can see the the logo files in RSS folder but there's nothing in the tracking center not even the original launch site menu button?

One other thing I noticed is bump maps aren't working anymore.

Edited May 29, 2014 by pingopete

[NathanKell]

SpacedInvader: Falcon 9 v1.1 has the highest upper stage starting TWR I'm aware of (for LF rockets), at 0.92. Proton comes close at 0.86. Delta II, Delta IV, and Atlas V all have around 0.25 starting TWR, but they're optimized for GTOs. You probably want to start somewhere around 0.5-0.7, as you say, depending on how high your lower stage is lofting you, how much dV your upper stage must make up, and how high a final (or parking) orbit you want. The lower the orbit, the larger the proportion of dV is in the stage, the higher a TWR you'll need (really, that is to say, the shorter the amount of time you'll have).

When you circularize after apogee, i.e. into a lower orbit, you must then burn radial to lower your apogee; that's part of the circularization process (accelerate to orbital velocity + counteract gravity, rather than traditional circularization where you just do the former). And yes, you'll have to make your lower stage loft you higher. However, this can still be more efficient (or at least cheaper! Since tanks and fuel are cheap, and engines are expensive) than investing in a higher-thrust upper stage, even one that would lead to a lesser expenditure of dV.

You have essentially three "good" options for your orbital stage.

1. Super-high-TWR solids that fire at apogee (Juno I/II, most all-solid launchers, etc.).

2. Medium-thrust liquid stage that circularizes at apogee (or shortly after). TWR as you say.

3. Low-thrust liquid stage that circularizes well after initial apogee (needs to be lofted higher by lower stage(s), and spend time burning at >0 pitch after apogee).

#1 is best when you don't have reliable startable engines or good upper-stage guidance ("point level to earth, light fuse at apogee" is much easier for 1950s tech).

#2 is best for LEO, especially low parking orbits prior to other things occurring.

#3 is best for GTO, but can be used for LEO missions as well (probably not as efficient, although perhaps as above cheaper, than #2). But for GTO, your payload mass is less, you get lofted, if not higher, certainly with a higher initial velocity from your lower stage, so 0.25 TWR makes sense.

#4 is high-thrust liquid upper. It's like a solid impersonating a liquid, IMO. You have to treat it more like a solid: don't fire it until you know it won't finish the burn until after apogee.

pingopete: I will check the ocean-gray thing, which I haven't seen. But EVE Overhaul *does* mess with specularity, and removes normal maps and the blue ramp shading at the world's edge. Also, nothing past Overhaul-8 works right with RSS, and even -8 doesn't work if "wrap" is on in RSS. rbray is aware.

As for launch sites: no icons are being displayed on the planet in tracking center? There are no buttons on the upper right screen edge for it?

[Lord Aurelius]

I found a strange glitch with Dres/Saturn. While trying to send a probe down through the atmosphere, the probe descended normally down to about 400k where the airspeed abruptly passed 0 and the probe began rapidly accelerating backwards until it eventually broke apart due to aerodynamic stresses at around 9km/s (I'm using RO with DeadlyReentry).

Has anyone else experienced this?

[Starwaster]

I found a strange glitch with Dres/Saturn. While trying to send a probe down through the atmosphere, the probe descended normally down to about 400k where the airspeed abruptly passed 0 and the probe began rapidly accelerating backwards until it eventually broke apart due to aerodynamic stresses at around 9km/s (I'm using RO with DeadlyReentry).

Has anyone else experienced this?

I'm not currently up to date on RSS, but this sounds suspiciously like something I ran into when testing very deep gas giant atmospheres. Except it didn't accelerate backwards. But it's reentry FX did point in a direction that was perpendicular to its velocity vector.

If the latest version of RSS is experimenting with realistic gas giant atmospheres then there's going to be problems (probably best not to try to simulate it all the way down to core, just down to the metallic region.... that might be ok)

[White Owl]

I just tried out the latest RC, and my planets look just like PingoPete's. Also, the cloud layers are seriously off; the cloud altitude appears to be about halfway to geostationary orbit.

I uninstalled Environmental Visual Enhancements, so the clouds are gone. But the weird luminescent grey oceans remain.

[SpacedInvader]

SpacedInvader: Falcon 9 v1.1 has the highest upper stage starting TWR I'm aware of (for LF rockets), at 0.92. Proton comes close at 0.86. Delta II, Delta IV, and Atlas V all have around 0.25 starting TWR, but they're optimized for GTOs. You probably want to start somewhere around 0.5-0.7, as you say, depending on how high your lower stage is lofting you, how much dV your upper stage must make up, and how high a final (or parking) orbit you want. The lower the orbit, the larger the proportion of dV is in the stage, the higher a TWR you'll need (really, that is to say, the shorter the amount of time you'll have).

When you circularize after apogee, i.e. into a lower orbit, you must then burn radial to lower your apogee; that's part of the circularization process (accelerate to orbital velocity + counteract gravity, rather than traditional circularization where you just do the former). And yes, you'll have to make your lower stage loft you higher. However, this can still be more efficient (or at least cheaper! Since tanks and fuel are cheap, and engines are expensive) than investing in a higher-thrust upper stage, even one that would lead to a lesser expenditure of dV.

You have essentially three "good" options for your orbital stage.

1. Super-high-TWR solids that fire at apogee (Juno I/II, most all-solid launchers, etc.).

2. Medium-thrust liquid stage that circularizes at apogee (or shortly after). TWR as you say.

3. Low-thrust liquid stage that circularizes well after initial apogee (needs to be lofted higher by lower stage(s), and spend time burning at >0 pitch after apogee).

#1 is best when you don't have reliable startable engines or good upper-stage guidance ("point level to earth, light fuse at apogee" is much easier for 1950s tech).

#2 is best for LEO, especially low parking orbits prior to other things occurring.

#3 is best for GTO, but can be used for LEO missions as well (probably not as efficient, although perhaps as above cheaper, than #2). But for GTO, your payload mass is less, you get lofted, if not higher, certainly with a higher initial velocity from your lower stage, so 0.25 TWR makes sense.

#4 is high-thrust liquid upper. It's like a solid impersonating a liquid, IMO. You have to treat it more like a solid: don't fire it until you know it won't finish the burn until after apogee.

pingopete: I will check the ocean-gray thing, which I haven't seen. But EVE Overhaul *does* mess with specularity, and removes normal maps and the blue ramp shading at the world's edge. Also, nothing past Overhaul-8 works right with RSS, and even -8 doesn't work if "wrap" is on in RSS. rbray is aware.

As for launch sites: no icons are being displayed on the planet in tracking center? There are no buttons on the upper right screen edge for it?

So this sort of returns me to the question of how to distribute DV between stages. While I know I don't need to worry about surface vs. vacuum, now I'm curious how much my first stage should have compared to my second. Experience tells me it only takes about 4000m/s to get a good distance out of the atmosphere, so is that enough for my first stage? I normally go for about a 50/50 split, with around 4500m/s on this first / first+booster stage and then about 4500m/s on the second stage. I'm guessing that there are lots of different ways to do this, but am I doing it generally right? Or should I be putting more DV in the second stage and less on the first?

Another question I've got now is aside from cost, is there any reason to go with one over another? One wonderful benefit of working in the game world, at least for right now, is that you don't have to worry about budgetary constraints telling you to go for the cheaper option, at least for now, so engines are as cheap as fuel (free).

[pingopete]

Thanks for reply, Yeah I'll give it a try with O8. The TC issue I'll look into further, it may be that O9 was messing that up too. And yeah it was as if the plugin for any RSS related GUI wasn't working :/ I'll report back when I've figured it out.

[griffin247]

i was wondering if some clever type chap has thought of doing a chart telling the DV requied to get a 1 Tonne sat into orbit for both high and low space. only asking as am struggleing to get my vanquard to high space .

[AndreyATGB]

You need around 9-10 km/s delta-v for LEO. You're gonna need to define what high means, if it's GEO then that'll be about 4km/s extra. It doesn't matter what payload you have, it's the same delta-v.

[griffin247]

You need around 9-10 km/s delta-v for LEO. You're gonna need to define what high means, if it's GEO then that'll be about 4km/s extra. It doesn't matter what payload you have, it's the same delta-v.

ok i see thankies

[NathanKell]

SpacedInvader: a good rule of thumb is to divide dV evenly between stages. However, that holds only when the Isp is similar across stages. If your upper is hydrolox, it makes sense to make it proportionally larger (like 3:2 or even 2:1, although the latter implies a long burntime). As with all these things, if you want a good starting point, try replicating real launchers. Make each stage as heavy as it should be (adding ballast if necessary), give it the appropriate fuel and thrust, and see how it works.

There's little reason other than flavor to go with any approach except the one that seems easiest / preferable to you. I like variety, so I generally try all sorts of approaches (apogee kick solids, low-TWR long-burn hydrolox, high-thrust hydrocarbon, etc).

pingopete: cool. I'll also check on the gray stuff.

griffin247: recall that RSS is the real solar system. You don't have to ask KSPers when you need information; you can google information about real rocket science. For instance, Wikipedia's DeltaV tables.

[SpacedInvader]

i was wondering if some clever type chap has thought of doing a chart telling the DV requied to get a 1 Tonne sat into orbit for both high and low space. only asking as am struggleing to get my vanquard to high space .

Also, DV is a value based on the masses of the rocket, so the amount of DV it takes to lift a 1T payload should be the same as it takes to lift a 100T payload. The difference will arise when you start trying to figure out how much fuel it will take for each...

SpacedInvader: a good rule of thumb is to divide dV evenly between stages. However, that holds only when the Isp is similar across stages. If your upper is hydrolox, it makes sense to make it proportionally larger (like 3:2 or even 2:1, although the latter implies a long burntime). As with all these things, if you want a good starting point, try replicating real launchers. Make each stage as heavy as it should be (adding ballast if necessary), give it the appropriate fuel and thrust, and see how it works.

There's little reason other than flavor to go with any approach except the one that seems easiest / preferable to you. I like variety, so I generally try all sorts of approaches (apogee kick solids, low-TWR long-burn hydrolox, high-thrust hydrocarbon, etc).

pingopete: cool. I'll also check on the gray stuff.

griffin247: recall that RSS is the real solar system. You don't have to ask KSPers when you need information; you can google information about real rocket science. For instance, Wikipedia's DeltaV tables.

I occasionally try to replicate RL rockets, but as I said a long time ago (months at this point), a big chunk of the fun of KSP for me is in designing and building my own to see how they stack up. That said, I may try a couple more to refine my skills.

EDIT: Here's a new question that has cropped up... How much delta-v should be needed to land from orbit on the Moon? The Apollo DV budget for both descent and ascent from the Moon was ~6000f/s or ~1800m/s, but when I tried that, I ended up using just that much to de-orbit, leaving me with almost nothing to actually land. I've since upped my descent stage to 3000m/s, but it's *huge* (3m diameter by 1.5m height) and this is just a probe lander, I can imagine what its going to look like when I try to land a two man pod.

EDIT2: 300! THIS IS SPARTA!!!!

Edited May 30, 2014 by SpacedInvader

[ThorBeorn]

Maybe this belongs to the EVE thread but I wonder, has anyone come up with a satisfying setup for the clouds in Enviromental Visual Enhancements for RSS? Is there anything more to do besides slowing clouds down and rasing altitude a few thousand meters?

The cloud layer in my game is not perfectly spherical but rather looks like a bunch of hexagons, sometimes with very pronounced angles between them - not pretty at all, is it fixable? From orbit it looks great though.

Also, can the white in the atmosphere at the horizon be changed?

[AndreyATGB]

The EVE Overhaul looks much better and you don't have to change the altitude yourself. However it seems to conflict with RSS at the moment. So as far as I know, there's nothing you can do for the official version of EVE.

I tried to get rid of the white and it is possible by using atmosphere from ground in the RSS config but that produces some weird multicolored bands visible from orbit. I think overhaul is also going to fix this issue when it is released, rbray mentioned he wants to get rid of the white horizon.

To expand on atmosphere from ground, you can use the wavelengths from better atmospheres and write them in your RSS install. Remove the foo from AtmosphereFromGround and it'll work.

Edited May 31, 2014 by AndreyATGB

[NathanKell]

SpacedInvader: I'm not suggesting *using* replica rockets; I'm just saying use the VAB as a calculator to figure out what the dV apportionment (and TWR range is on real rockets. It's more fun than doing natural logs on paper or in Excel!

2000m/s should be plenty, even including DOI burn. What kind of descent orbit insertion burn are you doing!? You should only lower your periselene from LLO of ~100km to about 3km (so you now have a 100x3km orbit) and then do a "reverse gravity turn" burning mostly retrograde the whole way in. That kind of DOI should *not* be very expensive at all.

ThorBeorn: as AndreyATGB mentions, tweaking AFG (you can do it ingame with ALT-G in flight) will deal with the horizon. EVE Overhaul does work better, although Overhaul v8 is the last version that works with RSS, and even that has some issues (1. Clouds seem to disappear after revert; 2. requires wrap=false for Kerbin; 3. no normal mapping on the scaled space shader; 4. limited specularity.

rbray is working on all of it...