Non-RO launch vehicles for RSS

[CFYL]

I'm using this post to reply to some of the questions/ problems, and some of my own experience and statements.

1. Downloads: I'm running KSP 1.8.1 with RSS 16.2, which was meant for KSP 1.7x (I thought), but everything is fine except for lagging about 15 secs each scene change, which is fine for me using a mac that dates back to 2013. I'm using ModuleManager 4.1.3 and the corresponding Kopernics (The readme of Kopernics wasn't in the GameData folder). All of my other mods are for 1.8x or 1.9x and ModuleManager did manage everything. I am sorry if I made you delete some up-to-date mods @Pds314

2. Payload: It' okay if you stack a large holding tank with ore so it weighs 17 tons and add some other parts. I'd say 20 tons is feasible because SLS can bring 130 tons into LEO and CZ-9 can get 66 tons to GTO, so a 20 ton GEO is possible, although these rockets would probably not be used for such purposes. As for the "inert mass" question, I would say that, it means the mass which is in GEO but not the engine and fuel tank you use to bring it up. You can use anything for the 20 ton, like something your own mission would use, or just a piece of space junk which does nothing. Sorry for not being clear. @moar ssto

3. Sector: I first posted this thread in the spacecraft exchange, and I asked the staff to help move it here. I think it can be categorized as a challenge, tough both for us and the computer CPU. 

4. Latitude: I prefer to launch my rockets in Wenchang or Xichang, China. The 30N and 30S are just for reference, because high latitude launch site would make it harder to reach a real geostationary orbit, not just an inclined synchronous orbit, and the earth's rotation would give you less help if you launch there, which I think you all know long before I tell you. They're welcomed for a harder try.

BTW, the final orbit is the payload's orbit after decoupling the final engine and its tanks used, which will make a slight but detectable change to the orbit. When I launched the first part of my LEO station, I found out my apogee at 400km and perigee at 399.5km or so. So I faced prograde and decoupled the upper stage at the apogee, turned out just enough to put it in a perfect 400 km orbit with no more than 500m of deviation. Not guaranteed. There is also a design, using only one (or a cluster of) rocket engines and decouple spent tanks on the top, with the payload just above the engine. I'm not sure if it works but it was studied seriously by rocket scientists, in real world, but not so successful as far as I know.

P.S.: I'm a Chinese Junior Middle School student and will start school the day after tomorrow. I love real space missions and real physics more than simulated ones, which is why I try to keep simulated ones simple and not overriding real ones, but with a sense of challenge so I installed RealSolarSystem, FerramAerospaceResearch, PersistentRotation,  and TACLS. Hence I won't visit the forum very often because I should absolutely lay the focus on school. I'll also play KSP a lot less often so maybe I won't post my own craft here until very late if I will post it. KSP is great game and simulator, and it has helped me a lot in my orbital physics learning, through books and KSP as our school doesn't have this course but I love it. Our Physics lesson is still talking about friction and Gravity, in their linear and low-speed forms. Nevertheless, I admire KSP, squad, it's modders, and everyone around here. I would really hope some effects of the theory of relativity can be added as stock or mods features though. I was nearly mad when I found out that I can't launch a SSO satellite.

Still, I will check the forum once a week or so, to keep up with you guys and modify some of my contents. As I mentioned, I'm Chinese so imgur doesn't work here, and I can't see its pictures because our government blocks some overseas links. No need to change a image-sharing website for me though, you can just include some of your data in the text and you can still see it each other, if, you would really like to participate. I can also speak English without translators, so just take it easy, but I may make grammar mistakes and typos.

Yeah it's pretty late here but is it noon in the US or afternoon in Europe? Anyway, good night, I'll sleep tight. 

Edited May 16, 2020 by AllenLi

[Flying dutchman]

well...  i built a 4600 ton lv that has the capabillity to put a whopping 30 tons into orbit...

 

the dry mass of stock tanks is redicilously high

[moar ssto]

1 hour ago, Flying dutchman said:

well...  i built a 4600 ton lv that has the capabillity to put a whopping 30 tons into orbit...

 

the dry mass of stock tanks is redicilously high

Staging should be very frequent, if using frequent asparagus staging and high initial twr, you can get a payload fraction of 2%-2.2%. But if you mean 30t into geo, that's really good.

Edited May 16, 2020 by moar ssto

[Flying dutchman]

2 hours ago, moar ssto said:

Staging should be very frequent, if using frequent asparagus staging and high initial twr, you can get a payload fraction of 2%-2.2%. But if you mean 30t into geo, that's really good.

no, leo sadly..

[Pds314]

Oof. Just realized 1.7.3 means no big SRBs. I'm gonna try to install 1.8 or 1.9.

Edited May 16, 2020 by Pds314

[Pds314]

8 hours ago, AllenLi said:

I'm using this post to reply to some of the questions/ problems, and some of my own experience and statements.

1. Downloads: I'm running KSP 1.8.1 with RSS 16.2, which was meant for KSP 1.7x (I thought), but everything is fine except for lagging about 15 secs each scene change, which is fine for me using a mac that dates back to 2013. I'm using ModuleManager 4.1.3 and the corresponding Kopernics (The readme of Kopernics wasn't in the GameData folder). All of my other mods are for 1.8x or 1.9x and ModuleManager did manage everything. I am sorry if I made you delete some up-to-date mods @Pds314

2. Payload: It' okay if you stack a large holding tank with ore so it weighs 17 tons and add some other parts. I'd say 20 tons is feasible because SLS can bring 130 tons into LEO and CZ-9 can get 66 tons to GTO, so a 20 ton GEO is possible, although these rockets would probably not be used for such purposes. As for the "inert mass" question, I would say that, it means the mass which is in GEO but not the engine and fuel tank you use to bring it up. You can use anything for the 20 ton, like something your own mission would use, or just a piece of space junk which does nothing. Sorry for not being clear. @moar ssto

3. Sector: I first posted this thread in the spacecraft exchange, and I asked the staff to help move it here. I think it can be categorized as a challenge, tough both for us and the computer CPU. 

4. Latitude: I prefer to launch my rockets in Wenchang or Xichang, China. The 30N and 30S are just for reference, because high latitude launch site would make it harder to reach a real geostationary orbit, not just an inclined synchronous orbit, and the earth's rotation would give you less help if you launch there, which I think you all know long before I tell you. They're welcomed for a harder try.

BTW, the final orbit is the payload's orbit after decoupling the final engine and its tanks used, which will make a slight but detectable change to the orbit. When I launched the first part of my LEO station, I found out my apogee at 400km and perigee at 399.5km or so. So I faced prograde and decoupled the upper stage at the apogee, turned out just enough to put it in a perfect 400 km orbit with no more than 500m of deviation. Not guaranteed. There is also a design, using only one (or a cluster of) rocket engines and decouple spent tanks on the top, with the payload just above the engine. I'm not sure if it works but it was studied seriously by rocket scientists, in real world, but not so successful as far as I know.

P.S.: I'm a Chinese Junior Middle School student and will start school the day after tomorrow. I love real space missions and real physics more than simulated ones, which is why I try to keep simulated ones simple and not overriding real ones, but with a sense of challenge so I installed RealSolarSystem, FerramAerospaceResearch, PersistentRotation,  and TACLS. Hence I won't visit the forum very often because I should absolutely lay the focus on school. I'll also play KSP a lot less often so maybe I won't post my own craft here until very late if I will post it. KSP is great game and simulator, and it has helped me a lot in my orbital physics learning, through books and KSP as our school doesn't have this course but I love it. Our Physics lesson is still talking about friction and Gravity, in their linear and low-speed forms. Nevertheless, I admire KSP, squad, it's modders, and everyone around here. I would really hope some effects of the theory of relativity can be added as stock or mods features though. I was nearly mad when I found out that I can't launch a SSO satellite.

Still, I will check the forum once a week or so, to keep up with you guys and modify some of my contents. As I mentioned, I'm Chinese so imgur doesn't work here, and I can't see its pictures because our government blocks some overseas links. No need to change a image-sharing website for me though, you can just include some of your data in the text and you can still see it each other, if, you would really like to participate. I can also speak English without translators, so just take it easy, but I may make grammar mistakes and typos.

Yeah it's pretty late here but is it noon in the US or afternoon in Europe? Anyway, good night, I'll sleep tight. 

Hmmm. Does Google drive work in China? I know American private companies often don't meet Chinese requirements and get blocked. As for physics and gravity in middle school, American middleschool students don't even take Algebra until their final year.

 

Edit: Google drive appears to be blocked. Flickr is blocked. YouTube is blocked. Dropbox is blocked. MS One drive is blocked.

 

Weiyun might be an option... pretty sure there's no English version though so people who don't speak Chinese might have to use translator programs. Not sure if it requires downloadable though which some people might not be super comfortable with.

Edited May 17, 2020 by Pds314

[Pds314]

Hmmmmm...

Tested using characters to form an image. Not especially good. You can identify general shapes and colors but not specific parts and there forum adds annoying line breaks I can't seem to remove even replacing a hundred lines of enter with shift-enter.

Edited May 17, 2020 by Pds314

[Pds314]

test

Edited May 17, 2020 by Pds314

[Pds314]

Ooh.  That's not good. Let's uh... pretend this didn't happen. 16 Clydesdales are going to make a hard landing here....

 

Uh... hmmm... Apparently in the same launch, these things are gonna hit Japan.

Edited May 17, 2020 by Pds314

[Pds314]

Well, I've managed to develop a 70-tonne class launcher. It's NOT LIGHT. With a payload it's over 6000 tonnes.

Is it wierd to anyone else that the wolfhound sans baseplate has a 0.625m node? xD

Wait... Was your "67 tonne" single stage transfer stage including or excluding payload? I was thinking it was total vehicle weight, with the payload.

My transfer stage design with 3 levels of drop tanks on a wolfhound has 4005 vac DV for 20 tonnes of payload if the control source is included in the payload. It weighs 80.4 tonnes if payload is included.

Edited May 17, 2020 by Pds314

[Pds314]

Ok. I think my rocket might be more like 100-tonne class. I just didn't know how to fly it properly. Because it got my 80.5-tonne payload into orbit with Delta-V to spare.

[moar ssto]

2 hours ago, Pds314 said:

Well, I've managed to develop a 70-tonne class launcher. It's NOT LIGHT. With a payload it's over 6000 tonnes.

Is it wierd to anyone else that the wolfhound sans baseplate has a 0.625m node? xD

Wait... Was your "67 tonne" single stage transfer stage including or excluding payload? I was thinking it was total vehicle weight, with the payload.

My transfer stage design with 3 levels of drop tanks on a wolfhound has 4005 vac DV for 20 tonnes of payload if the control source is included in the payload. It weighs 80.4 tonnes if payload is included.

I mean just the transfer stage alone, with payload its more than 80t.

2 hours ago, Pds314 said:

Well, I've managed to develop a 70-tonne class launcher. It's NOT LIGHT. With a payload it's over 6000 tonnes.

Is it wierd to anyone else that the wolfhound sans baseplate has a 0.625m node? xD

Wait... Was your "67 tonne" single stage transfer stage including or excluding payload? I was thinking it was total vehicle weight, with the payload.

My transfer stage design with 3 levels of drop tanks on a wolfhound has 4005 vac DV for 20 tonnes of payload if the control source is included in the payload. It weighs 80.4 tonnes if payload is included.

I don't think the low isp os solids will give you any advantage in terms of efficiency, I use LFO for strap on boosters exclusively, which also help you to create asparagus staging.

[Pds314]

TFW you can get to a circular equatorial 900,000 km orbit, or escape, then line up a Kerbin Earth encounter 15 years from now, then another in 35, then another in like 80, but can't get a circular equatorial 36000 km orbit regardless of what you do because dropping the Apogee takes too much fuel.

34 minutes ago, moar ssto said:

I mean just the transfer stage alone, with payload its more than 80t.

I don't think the low isp os solids will give you any advantage in terms of efficiency, I use LFO for strap on boosters exclusively, which also help you to create asparagus staging.

Not mass efficiency, but on the first stage, having a bunch of Clydesdales is good for cost efficiency and getting the TWR up to reasonable.

Edited May 17, 2020 by Pds314

[Pds314]

As for sun-synchronous satellites, yeah it is unfortunate but treating planets as perfect spherical gravity sources unfortunately means that using the Earth's oblate shape to perturb your orbit isn't gonna work. Not even in Principia. I do wanna just mention though that you can very well put a satellite in an orbit meant to only have the Earth cross its orbital path a twice a year, and make sure it will always be in a completely different part of its orbit.

Edited May 17, 2020 by Pds314

[Pds314]

As to the possibility of making objects oblate with oblate gravitational fields, that might be possible in a mod. It's a question of integrating gravity over the whole object's hydrostatic equilibrium shape and finding an equation which describes the gravitational force vector nearby.

 

More complex would be computing gravitational force torques and hydrostatic equilibrium shape due to dynamic rotation rate and direction and tidal effects for elliptical orbits not in a plane. In all cases it probably isn't analytically solvable. But in that case you might not even be able to get deterministic equations for how objects should distort. If you could do that, you'd also need a solution for objects that have no equilibrium shape. I.E. get overspun or spaghettified, so it doesn't just crash when it gets an oblateness of infinity or something.

 

All in all, I think that would be very hard to do. Even just calculation of gravitation of an oblate spheroid of constant density should be pretty complicated and guaranteed that there's no such thing as "on-rails" warp.

Basically any modification to gravity that doesn't have analytical solutions will break on-rails warp unless you just want a makeshift "precession factor" function that takes in an orbit and says how fast it should swivel in a predictable way.

Edited May 17, 2020 by Pds314

[moar ssto]

2 hours ago, Pds314 said:

As for sun-synchronous satellites, yeah it is unfortunate but treating planets as perfect spherical gravity sources unfortunately means that using the Earth's oblate shape to perturb your orbit isn't gonna work. Not even in Principia. I do wanna just mention though that you can very well put a satellite in an orbit meant to only have the Earth cross its orbital path a twice a year, and make sure it will always be in a completely different part of its orbit.

For rss, principia does consider the oblateness of earth by using higher order spherical harmonics.

[Pds314]

3 minutes ago, moar ssto said:

For rss, principia does consider the oblateness of earth by using higher order spherical harmonics.

wait really???? When did they make that?

 

[moar ssto]

On 5/17/2020 at 11:07 AM, Pds314 said:

Ooh.  That's not good. Let's uh... pretend this didn't happen. 16 Clydesdales are going to make a hard landing here....

 

Uh... hmmm... Apparently in the same launch, these things are gonna hit Japan.

I guess you can improve a lot if you stage using asparagus staging and making the first stage smaller, so that when you reach a reasonable altitude, you can use vacuum engines such as rhino. Also, gravity turn should happen a bit earlier.

[Pds314]

1 hour ago, moar ssto said:

I guess you can improve a lot if you stage using asparagus staging and making the first stage smaller, so that when you reach a reasonable altitude, you can use vacuum engines such as rhino. Also, gravity turn should happen a bit earlier.

The only stage burning there is Rhino. =D

As for asparagus, maybe. But TWR was there reason I was doing such a high turn anyway. I start that stage well before the previous one is completed. The image was before I had a good ascent profile for this vehicle figured out, but now I ignite quad-Rhino core at 12 km altitude. Making the side boosters asparagus to each other, but not the core, might be worth it.

Edited May 18, 2020 by Pds314

[Laie]

Been trying to solve this on paper...

LEO(KSC 23°)-> Geo requires about 4200m/s, with 20t payload and lots of nuke power I end up with 60t gross mass for that part of the mission.

Below that, a Rhino upper stage with 4Min burn time, starting at TWR 0.87 for 3200m/s. Still reasonable.

And then Tsiolkowski beats down hard: wrapping the above in eight Mammoths isn't quite enough, dV-wise, and TWR would be abysmal throughout. I'm used to RO launches where you'd reach 3-5g at the end of each stage, and have no idea how it would work out with an asparagus design that hardly ever reaches 2g. My guess is that it would require more like 12km/s to make orbit, rather than the 9+km/s I'm used to.

In a nutshell, I don't think it's worthwhile to use stock parts in a RSS setting. The good old MOAR approach will eventually get you there, but it's not the kind of challenge I'd enjoy.

[moar ssto]

21 minutes ago, Laie said:

Been trying to solve this on paper...

LEO(KSC 23°)-> Geo requires about 4200m/s, with 20t payload and lots of nuke power I end up with 60t gross mass for that part of the mission.

Below that, a Rhino upper stage with 4Min burn time, starting at TWR 0.87 for 3200m/s. Still reasonable.

And then Tsiolkowski beats down hard: wrapping the above in eight Mammoths isn't quite enough, dV-wise, and TWR would be abysmal throughout. I'm used to RO launches where you'd reach 3-5g at the end of each stage, and have no idea how it would work out with an asparagus design that hardly ever reaches 2g. My guess is that it would require more like 12km/s to make orbit, rather than the 9+km/s I'm used to.

In a nutshell, I don't think it's worthwhile to use stock parts in a RSS setting. The good old MOAR approach will eventually get you there, but it's not the kind of challenge I'd enjoy.

Just exchange dv for twr, most of my rockets have initial twr of not less than 1.5, the heavy stock tanks and low isp of lower stages means its usually better to give the vehicle less fuel and more engines. This way, you can still reach close to 3g when the core burns out and overll dv to reach orbit is usually between 8.8 to 9.4km/s. And while for stock part rss, moar approach is only true for launching, anything starting from leo will require up to orders of magnitude less mass than in RO depedning on the mission. (with stock part rss, I do every interplanetary mission with single launch and rocket not bigger than 5400t(enough for landing on and returning from venus and moon), while in ro I barely see people doing single lauch interplanetary manned missions.

Edited May 18, 2020 by moar ssto

[moar ssto]

46 minutes ago, Pds314 said:

The only stage burning there is Rhino. =D

As for asparagus, maybe. But TWR was there reason I was doing such a high turn anyway. I start that stage well before the previous one is completed. The image was before I had a good ascent profile for this vehicle figured out, but now I ignite quad-Rhino core at 12 km altitude. Making the side boosters asparagus to each other, but not the core, might be worth it.

I got that, since you are factoring in cost, moar twr isn't an option.

[bayesian_acolyte]

10 hours ago, Laie said:

And then Tsiolkowski beats down hard: wrapping the above in eight Mammoths isn't quite enough, dV-wise, and TWR would be abysmal throughout. I'm used to RO launches where you'd reach 3-5g at the end of each stage, and have no idea how it would work out with an asparagus design that hardly ever reaches 2g. My guess is that it would require more like 12km/s to make orbit, rather than the 9+km/s I'm used to.

In a nutshell, I don't think it's worthwhile to use stock parts in a RSS setting. The good old MOAR approach will eventually get you there, but it's not the kind of challenge I'd enjoy.

It's not that bad. In that link I posted earlier I launched ~25 tons to LEO with 5 twin boars, 6 kickbacks, 2 poodles, and a NERV, at less than 200k cost and ~900 tons. Using drop tanks/asparagus helps, especially for TWR in later early stages. Like @moar ssto was saying about TWR, I was starting around 1.6 and going up to ~3.5 before I started dropping boars. I haven't tried to scale it up to deliver 20t to GEO but I'd guess it's possible to do under 1500 tons and 300k cost (not easily). Not sure how FAR or that parts mod mandated by the OP might affect things though.

10 hours ago, moar ssto said:

I got that, since you are factoring in cost, moar twr isn't an option.

In my experience using higher average TWR designs lowered the cost (to a point at least). 

[moar ssto]

4 hours ago, bayesian_acolyte said:

It's not that bad. In that link I posted earlier I launched ~25 tons to LEO with 5 twin boars, 6 kickbacks, 2 poodles, and a NERV, at less than 200k cost and ~900 tons. Using drop tanks/asparagus helps, especially for TWR in later early stages. Like @moar ssto was saying about TWR, I was starting around 1.6 and going up to ~3.5 before I started dropping boars. I haven't tried to scale it up to deliver 20t to GEO but I'd guess it's possible to do under 1500 tons and 300k cost (not easily). Not sure how FAR or that parts mod mandated by the OP might affect things though.

In my experience using higher average TWR designs lowered the cost (to a point at least). 

That's a whole lot efficient than my rockets,I only get payload fractions close to 2.2%, if not counting those practically useless creations. I think FAR will flavour a steeper ascend since staying in the low atmo at high speed is dangerous.

How much dv did you put in the LVN stage?

Edited May 19, 2020 by moar ssto

[bayesian_acolyte]

 

Just now, moar ssto said:

How much dv did you put in the LVN stage?

It used a bit over 1km/s worth of fuel, but the efficiency was only something like 60% converting that into orbital speed because of the low TWR (<0.25). The whole LVN stage was like 11.5 km/s dV so it was only using the start of it. I was maximizing for cost and post-LEO dV, so I only wanted to use one LVN, and that was about as much as I could pull off using it on the ascent with the TWR so low. If I was maximizing for launch weight instead of cost, I might try to add more engines and use them for more of the ascent, but not sure it would make much positive difference because of the low TWR.

Spoiler