Kerbal Space Program

[hobbsyoyo]

I managed to finally dock my transit stage to the lander. It took multiple attempts, at one point my ships were nose to nose with docking ports touching but they wouldn't engage. I quicksaved, then tried to snap a screengrab and then the game crashed.

 

[warpus]

Is RO hard even if you give yourself unlimited money and/or play in sandbox mode and not career? Does it also simulate all of our planets as they actually exist, plus their moons?

If the answers to these questions are yes, maybe I should give this thing a try to see how hard it actually is to send people to Mars

Hobbs, I am so skeptical of your Eve mission, but I assume you did the math and your ship will be have enough fuel to do it. My approach to this mission is (in my head at least) completely different, with a much more giant approach. But I don't do any math and build in extreme contingency amounts in my designs, if possible

I also wish we had some alternatives to the NERVA engines. They weigh so much! On my interplanetary tugs I usually use 12 of them IIRC. That's a crazy amount I know, but my tugs are big and I have no time to wait around for burns. There needs to be enough thrust for my ships to do all their burns all in one go, in 10 minutes max. I wish there were smaller engines I could use, or more efficient ones even. I remember when the NERVA engines were more efficient in KSP. Unless I'm crazy and just imagining things

 

[cardgame]

It's our real solar system, yes. Alternatively I think there's an option to use RO with a 6.4x or 10x scaled-up Kerbin + Kerbol System? Never tried that one myself.

 

[warpus]

Does it give you any new parts? Or do you end up having to use regular stock parts? (assuming you don't install any other mods)

 

[hobbsyoyo]

Is RO hard even if you give yourself unlimited money and/or play in sandbox mode and not career? Does it also simulate all of our planets as they actually exist, plus their moons?

If the answers to these questions are yes, maybe I should give this thing a try to see how hard it actually is to send people to Mars

Hobbs, I am so skeptical of your Eve mission, but I assume you did the math and your ship will be have enough fuel to do it. My approach to this mission is (in my head at least) completely different, with a much more giant approach. But I don't do any math and build in extreme contingency amounts in my designs, if possible

I also wish we had some alternatives to the NERVA engines. They weigh so much! On my interplanetary tugs I usually use 12 of them IIRC. That's a crazy amount I know, but my tugs are big and I have no time to wait around for burns. There needs to be enough thrust for my ships to do all their burns all in one go, in 10 minutes max. I wish there were smaller engines I could use, or more efficient ones even. I remember when the NERVA engines were more efficient in KSP. Unless I'm crazy and just imagining things

Well it worked with some big hitches. I spent literally the entire day yesterday using the electric system to push the stack to Eve, then get into Eve orbit, then low Eve orbit, and finally dropping the lander off on a suborbital trajectory.

All.freaking.day.

There were some big problems on the descent, however. The landing course I chose landed me on the poles, which makes both launch and re-docking pretty challenging. Then I found out that the parachutes I chose for landing were drogues, not full parachutes. Even still, I landed at 12 m/s but this was enough to break the ship. Also, I realized after launch and all this work that I forgot to add 1000 units of xenon fuel on the lander for it to fully meet the contract stipulations. It does have enough fuel to land and return (it uses basically nothing for the landing) but it was such a beast to launch and assembly in orbit then take to Eve that I'd rather use bigger NERVA-based transfer stages.

So I reloaded to a point where I was still in orbit and I'm just going to use the lander to take the Kerbals directly home. I thought about delivering a rover with the units of fuel to attach to the lander but I decided I'd just rather reset the program and start over.

Now I plan on launching everything in pieces. There will be a base and five separate, 1-man lander/return ships. Then there will be a rover with a grabber to transfer crew between them. Finally, there will be a separate, much smaller transit stage to dock with the five landers and return the crew to Kerbin where they will dock with a small return capsule. The project just went from big to monolithic, though the individual pieces will be smaller.

There will be no way I can conceivably make money off this venture, however.


I have designed the lander and its mammoth launch vehicle and I'm doing launch tests. So far the entire lander stack checks out and it should have enough DV to get back to orbit from Eve. Unfortunately, the kerbal engineer kind of breaks when you do double-asparagus staging so I'm only 75% sure that's true.

It's launch vehicle is enormous and the injection stage uses 16x NERVA engines. It's proving difficult to fly so I'm having to do multiple test launches to get it right.

They did add mass to the NERVA engine and when they switched it to liquid fuel only, it limited the amount of optimal tanks for it. I don't mind the high mass (that's realistic) but I do wish they had larger engines available.

 

[cardgame]

Does it give you any new parts? Or do you end up having to use regular stock parts? (assuming you don't install any other mods)

Procedural Parts is a must for RAM consideration, then delete all fuel tanks. there's sooooo many, what a waste. It will prompt you with recommended part packs like one with real soviet engines.

 

[hobbsyoyo]

I deleted and re-installed CKAN and it still doesn't work.

 

[warpus]

I'm trying to build my version of the BFR. I've built the BFR spaceship and am now working on the BFR 1st stage. Took me a while to figure out how to add a docking port to the rocket exhaust part of the spaceship.. but I finally got it

One thing I'm a bit confused about.. Why would the BFR rocket ever need to refuel in Earth orbit? Isn't it possible to get the whole thing in orbit using the 1st stage, without using any fuel at all in the spaceship stage? If not, how will the BFR tanker get in orbit with full tanks of fuel? If it's possible to get the tanker in orbit all in one go, why can't you get the BFR spaceship all in one go? Shouldn't the tanker weigh more than a fully loaded BFR spaceship even?

 

[hobbsyoyo]

I'm trying to build my version of the BFR. I've built the BFR spaceship and am now working on the BFR 1st stage. Took me a while to figure out how to add a docking port to the rocket exhaust part of the spaceship.. but I finally got it

One thing I'm a bit confused about.. Why would the BFR rocket ever need to refuel in Earth orbit? Isn't it possible to get the whole thing in orbit using the 1st stage, without using any fuel at all in the spaceship stage? If not, how will the BFR tanker get in orbit with full tanks of fuel? If it's possible to get the tanker in orbit all in one go, why can't you get the BFR spaceship all in one go? Shouldn't the tanker weigh more than a fully loaded BFR spaceship even?

Answered here.

 

[warpus]

What's the stock KSP equivalent of the engines they use on the BFR spaceship stage?

 

[hobbsyoyo]

There isn't one. I haven't seen the TWR of the Raptor engine but if it's anything like the Merlin (used for F9) then it will be insanely high. And KSP engines have pretty terrible TWR so they miss out on that. And the Raptor will have a higher Isp than just about all the stock engines as well (and it doesn't even burn hydrogen) which again shows how awful KSP engines are.

So yeah, there is no equivalent or even a close analogue.

 

[warpus]

That sucks. That's probably why I'm having problems building an efficient BFR spaceship. I can get one from orbit to Duna orbit, but it won't have enough fuel to land I don't think. Plus refuelling takes 12 years, which is a problem.

 

[hobbsyoyo]

Landing shouldn't take a ton of fuel but fully utilizing that thin atmosphere will take some very careful planning.

 

[warpus]

Landing shouldn't take a ton of fuel but fully utilizing that thin atmosphere will take some very careful planning.

Hmm maybe I should give it a try. It's just that those engines don't seem great in terms of the efficiency you get.

 

[hobbsyoyo]

I think ideally you want a flyby trajectory that crosses in front of the planet with a low periapsis.
Crossing in front will slow your ship down due to gravity and a low periapsis means you'll dive through the thicker atmosphere enough to just burp the engines, throw out the chutes and land.

Barring that you should get into a very elliptical orbit (again, coming in in front of the planet to set it up) and then just barely skim the atmosphere on a bunch of passes to circularize. When you're roughly circular with a low periapsis, burp your engines and go in for a landing.

 

[warpus]

I think ideally you want a flyby trajectory that crosses in front of the planet with a low periapsis.
Crossing in front will slow your ship down due to gravity and a low periapsis means you'll dive through the thicker atmosphere enough to just burp the engines, throw out the chutes and land.

Hmmm I have never thought to consider the "in front of a planet" part.. but now I am able to fine-tune an entry vector to almost anything I want so I'll pay more attention to that

I also never do direct entries to a planet's atmosphere anymore. I always get in a low orbit first, and then drop down. I've had bad experiences with things exploding, so that's my new protocol and has been for a while. It does use up more fuel, but my usual ZEUS class interplanetary tugs have enough power to have pretty extensive mission profiles so for most missions for me it would probably not make a difference. But now with this BFR design I'm trying I might have to rethink that.. assuming these entries right into Duna's atmosphere are possible without a heat shield?

Here's my BFR spaceship part design so far. I don't really like calling it that because it only seats 4, but that's just the best way to describe what I'm trying to design. Here it is on its test flight to the Mun

Everything works great, and it's got enough reaction wheels to make landings easy enough, from what I've tested out. but I'm going to have to upgrade that ISRU and always bring an Engineer.. and even then the refuelling might be too slow. I was also considering adding more fuel, but..

Would this craft be good for direct entry into Duna's atmosphere? I guess since it did so well in Kerbin's atmosphere I might as well try?

Here it is getting into orbit. But I've since made this rocket even longer because I wanted to try out having more fuel. Have so far managed to get up to 1,600m/s before I have to detach the 1st stage. After that though it seems a real challenge to make the delivery system even more efficient (I really don't want to have to refuel right after getting in orbit)

The 1st stage is supposed to have enough parachutes for it to land back down smoothly so I can get that money back, but I don't know if that's going to work

 

[Thorgalaeg]

Are you using the stage recovery mod? I used it for a time but didnt like it. In the end it was all about adding lots of parachutes, which was tedious, unrealistic and added extra parts gratuitously.

 

[hobbsyoyo]

So I regularly dive into Duna's atmosphere without heatshields but I can't remember if I've done it from a flyby trajectory or not. I would tend to think you would need a heatshield to survive but I'm really not sure.

Also I would add a second stage to that stack by splitting the first stage about 2/3 of the way up and adding engines and a decoupler to the tank with fins on it midway up. Your stack is very inefficient if you are trying to get into orbit without burning fuel from your lander. Why is your first stage covered in solar panels?

I have tried to put a bunch of chutes on my first stages to save them but it never works, they always dissapear. I think if I put a probe control on it then they might survive because the game will think it's an active satellite and won't just automagically dissappear it.

 

[warpus]

Are you using the stage recovery mod? I used it for a time but didnt like it. In the end it was all about adding lots of parachutes, which was tedious, unrealistic and added extra parts gratuitously.

I was trying to do the recovery without mods. My parachute solutions didn't seem to work very well, but I probably just needed more parachutes.

Also I would add a second stage to that stack by splitting the first stage about 2/3 of the way up and adding engines and a decoupler to the tank with fins on it midway up. Your stack is very inefficient if you are trying to get into orbit without burning fuel from your lander.

I thought of adding a stage, but the BFR doesn't seem to have one. And it seems I can almost do it so I kept trying

At one point I was going to add a launch booster stage for the whole thing, which is not exactly what you're suggesting, but it would probably work. But I was sort of determined to keep everything reusable

Why is your first stage covered in solar panels?

Great question. It has three answers

1. One of my KSP "rules of building stuff" is that I always put certain things on each spaceship I'm building. Non-retractable solar panels, battery, backup battery, comm. dish, backup dish, a thermometer, and a probe control. And obviously a whole bunch of other stuff, but the stuff on the list always goes on so it's sort of automatic. As a result my space program never makes stupid engineering mistakes where something vital is missing, which used to actually happen quite a bit somehow.

But a 1st stage is not a spaceship (or is it?) but anyway I used to never follow this rule for the 1st stage because the 1st stage is garbage and just disappears in the atmosphere or the sea or whatever. Which brings us to point 2

2. I actually thought I would get the whole damn rocket in orbit in one go, and that I could then undock them and have 2 spaceship I'd be able to control. With that in mind my engineering rules of building stuff apply, and so I started adding some non-retractable solar panels. Which brings us to point 3

3. I was drinking

I have tried to put a bunch of chutes on my first stages to save them but it never works, they always dissapear. I think if I put a probe control on it then they might survive because the game will think it's an active satellite and won't just automagically dissappear it.

Yeah, you need to have a probe core on the 1st stage, so you can switch to it and control it. But the thing is you need to do that once you're already outside of the atmosphere. So if it's not possible to get in orbit with the whole rocket, what you essentially need to do is exit the atmosphere, undock, switch over to the 1st stage, land it, and then switch back to your payload and circularize.

Actually I guess you would circularize your payload before you land your 1st stage. Once you're done circularization your 1st stage should already be descending through the atmosphere, so you just switch to it and open its parachutes or whatever.

 

[hobbsyoyo]

Has anyone tried the expansion pack? I'm tempted to buy it but it will break a lot of the mods I have and the reviews are mixed at best.