Kerbal Space Program

Kerbal Space Program

Author
Discussion

Flibble

4,940 posts

125 months

Friday 8th March
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Early days for FlibbSpace so far, but I have managed to get my first kOS program going - it's a ground launch controller, which handles engine pre-firing checks for correct ignition and reaching take-off thrust and then launches the rocket. It also checks for a successful ascent and activates range safety if the rocket fails to lift off correctly. It will also separate the first stage automatically (I am using with on sounding rockets which have a very short booster fire time).

My boosted sounding rocket made it to 125 km and gathered some nice data.

Next step is to start on a guidance program so we can get to orbit.

fullbeem

2,025 posts

145 months

Friday 8th March
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I need to start playing this again. Was a easy play of an evening. Haven't touched it this year so far. I've never got any further than Minmus before restarting the career save.

Alias218

876 posts

106 months

Saturday 9th March
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I haven’t touched this game in over a year. Managed a return trip to Duna using an orbital mothership, and landed a science mission on Eve which maxed out my tech tree - never got as far as launching the enormous rocket I built to bring the brave Kerbals back home! Poor chaps are still up there, heaving against the crushing gravity.

They’re going to be built like brick sthouses by now!

BrettMRC

1,020 posts

104 months

Friday 22nd March
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Having read this thread, and been playing Simple Rockets and Simple Planes for ages... I am now downloading biggrin


RizzoTheRat

18,129 posts

136 months

Friday 22nd March
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The DLC is a load of real world parts and a system for doing mission challenges. I don't have it and am still loving the game after playing on and off for several years. Still loads of mods available and being developed.

DIW35

3,957 posts

144 months

Friday 22nd March
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It's changed and evolved a fair bit since 2015, but it's not necessary to acquire the DLC to enjoy the game still.

MartG

14,421 posts

148 months

Wednesday 3rd April
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"I believe this nation should commit itself to achieving the goal, before this decade is out, of landing a Kerbal on the Mun. The return part is optional."


RizzoTheRat

18,129 posts

136 months

Wednesday 3rd April
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biggrin

That's why I don't usually use Labs, but on my current game progress is rather slow due to doing everything with KOS so I stuck one in Mun orbit to earn some more science. Bloody hell they're slow! it's managing nearly 10 science per day having loaded it up with all the data from a couple of landings.
Then I went off to set up a Komms relay round Minmus and failed to spot the "Home" parameter of USI-LS, came back to find none of them working despite still having supplies and habitation rolleyes

Currently trying to figure out how to get my KOS docking script to cope with offset docking ports, trickier than I thought as it seems to use all vectors from the centre of mass not the controlling port, and then you have rotation caused by RCS translation...

BrettMRC

1,020 posts

104 months

Thursday 4th April
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I've done nothing yet other than experiment with space planes.

I have one that actually flies now.

Doesn't get to space, obviously! hehe

Flibble

4,940 posts

125 months

Friday 5th April
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My game is going slowly, still largely firing sounding rockets. The three stage sounding rocket made it almost to Canada.

My kos launch program can handle hot staging and separation motors for ullage now, and I have a single stage version of NASA's powered explicit guidance working.

I also knocked together an offline launch stimulator to test optimal pitch over settings (and validate the guidance). It can simulate 512 launches in about 3 seconds. Rather pleased with it.

RizzoTheRat

18,129 posts

136 months

Thursday 11th April
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Flibble said:
I also knocked together an offline launch stimulator to test optimal pitch over settings (and validate the guidance). It can simulate 512 launches in about 3 seconds. Rather pleased with it.
Interesting, what's the maths behind it? My launch script defines an altitude and pitch setting for the initial turn, and then follows prograde with a bearing correction the rest of the way to its target altitude. I'd fiddled around trying to derive the pitch angle from TWR and drag measurements based on experimental data, but it doesn't really work as different craft will stage at different times, and presumably it should take in to account the centre of mass and centre of pressure? What I generally do is try a "test" launch, and then revert to launch with updated values in the script.

So far in KOS I can do most of what I want to do terms of exploring the Mun and Minmus. The next big challenge will be to see if I can combine my precision landing and docking scripts to allow a skyscrane to assemble base components on Minmus.

Then I want to move from just aerobraking for capture and splashdown, to re-entering Kerbin orbit, docking with a VTOL SSTO, and then landing at the KSC under power (once I have enough science to resurrect my previous games SSTOs). Then I should be ready to try it all on Duna...
It's never ending biggrin

However at the moment I'm trying to tidy up my existing code and have broken quite a few of my code segments as I go through hacking reoccurring bits out and replacing them with functions to simplify the code a bit.

Flibble

4,940 posts

125 months

Thursday 11th April
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RizzoTheRat said:
Interesting, what's the maths behind it? My launch script defines an altitude and pitch setting for the initial turn, and then follows prograde with a bearing correction the rest of the way to its target altitude. I'd fiddled around trying to derive the pitch angle from TWR and drag measurements based on experimental data, but it doesn't really work as different craft will stage at different times, and presumably it should take in to account the centre of mass and centre of pressure? What I generally do is try a "test" launch, and then revert to launch with updated values in the script.
It runs a basic physics simulation of rocket flight, with some assumptions.
Gravity is based on an assumed spherical planet (which I think KSP uses anyway).
Drag is based on having a drag lookup table for the craft. I use FAR to generate me the table using it's Mach Sweep feature (I have a modded version which saves it to CSV). AoA is fixed at 0 degrees (it's assumed that the rocket is flying at zero AoA where it counts).

It's configured to run a simulation with varying pitch angle and pitch over speed. I then get a nice bunch of graphs and can poke through the data and pick a suitable pitch profile for the mission.

I'll generally try a test run using KRASH before launching as well.

Here's a screenshot, with my current orbital test vehicle (still needs a bit of tweaking):


Lots of data, the heatmaps at the side are usually the most interesting, along with the pitch profile in the main graphs.
The graph background also shows staging and flight phases.

RizzoTheRat said:
So far in KOS I can do most of what I want to do terms of exploring the Mun and Minmus. The next big challenge will be to see if I can combine my precision landing and docking scripts to allow a skyscrane to assemble base components on Minmus.

Then I want to move from just aerobraking for capture and splashdown, to re-entering Kerbin orbit, docking with a VTOL SSTO, and then landing at the KSC under power (once I have enough science to resurrect my previous games SSTOs). Then I should be ready to try it all on Duna...
It's never ending biggrin

However at the moment I'm trying to tidy up my existing code and have broken quite a few of my code segments as I go through hacking reoccurring bits out and replacing them with functions to simplify the code a bit.
There's loads to do. I've mainly been refining the staging and guidance loop. Staging is pretty reliable now, I can also cut engines short automatically and it somewhat handles engine failure mid flight. Guidance can somewhat recover from a partial engine failure, depending on remaining fuel.

RizzoTheRat

18,129 posts

136 months

Thursday 11th April
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Ah, I'm using stock aerodynamics so don't get that data, I've done on the fly drag calculations to try and predict impact point in atmosphere, which I then use to control the airbrakes when trying to land close to KSC, but never tried taking it quite that far.

I've never tried Realism Overhaul, so with a stock-ish game staging is simple (with the exception of drop tanks which I use on my current Mun lander, but I just have the quantity of fuel in the final stage as an input parameter) and I don't have to worry about engine failures. If I ever get all the orbital mechanics bits sorted out I guess that should be my next challenge.

Flibble

4,940 posts

125 months

Thursday 11th April
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The main issue for getting to orbit in RO is that you can't throttle your engines (for the most part) so you pretty much have to fly a correct ascent profile (or waste a tonne of fuel).

In the screenshot sim the rocket actually ends up flying down a little (horizontal pitch is middle of the graph) to get the orbit corrected. That said the orbit is hit to within 50 metres accuracy, so it seems to work!

I went with RO as I found stock was just a bit too straightforward in terms of flight dynamics - you just point in the right direction and it'll more or less work it out.

MartG

14,421 posts

148 months

Monday 15th April
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BrettMRC

1,020 posts

104 months

Monday 15th April
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...and heres me just about able to make the parts line up in the assembly building....

RizzoTheRat

18,129 posts

136 months

Monday 15th April
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BrettMRC said:
...and heres me just about able to make the parts line up in the assembly building....
Everyones first few craft result in large explosions. In fact most us of continue have occasional... well ok, regular.... explosions years later biggrin

Flibble

4,940 posts

125 months

Monday 15th April
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RizzoTheRat said:
Everyones first few craft result in large explosions. In fact most us of continue have occasional... well ok, regular.... explosions years later biggrin
While getting used to procedural fairings I managed to design a craft where the second stage literally fell off on the launchpad. Not my finest hour. hehe

BrettMRC

1,020 posts

104 months

Monday 15th April
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Had fun not taking enough oxidizer.

That crew is still up there somewhere....

RizzoTheRat

18,129 posts

136 months

Monday 15th April
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Flibble said:
While getting used to procedural fairings I managed to design a craft where the second stage literally fell off on the launchpad. Not my finest hour. hehe
I've had so many where I haven't got the staging order correct and blown up when engines start in the wrong order...
Or not enough struts (auto or otherwise) that it's fallen apart on the launch pad...
Or bad drag/mass layout that flip and explode before max Q...


So many ways to kill Kerbals...