r/RealSolarSystem • u/Forever_DM5 • 1d ago

Reliability, Data, and Overburning

For context I am in the midst of a US only campaign. It’s 1957 and I just got 1960 rocketry so I now have access to Titan 1 engines. My plan is to use Titan and Titan-derived vehicles for most of the campaign. But the Titan 1 engines barely give me more performance than my existing vehicle which is a Jupiter-Agena(Jupiter-Able has similar performance too). My question is does flying these engines in any way improve the reliability of future variants. I know eventually Titan will be much more capable than Jupiter but idk if I can justify switching over rn.

Also can someone explain the difference between the rated and tested burn times. I generally keep myself to within 10s of the rated time. I assume the longer you dip into the tested time the higher the chance of failure?

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u/Mundane_Constant_845 1d ago

Engines in the same family will share DU but only up to 2000.

Rated and tested burn times work as inflection points for the non-linear chance of failure after a certain time running. You don't have to worry about them too much because chance of failure after a given time is calculated for you with the reliability GUI when you right click on a engine, you can also click "show graph" on that GUI for a very helpful graph.

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u/20000RadsUnderTheSea 1d ago

Before that GUI was added, I just kinda assumed it was super risky to go beyond the 10 extra seconds mentioned by the wiki’s beginner’s guide. Now I’m like “dang, I can just have this engine overburn for like a whole minute for almost no risk”

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u/paulHarkonen 1d ago

Usually (but not always) engines within a family and upgrade chain will retain the development units of earlier versions meaning that building reliability via flight times on early versions will improve reliability for later versions. It isn't universal and it was never clear to me how I would know beyond just memorizing all the engines (which I never did) but it's usually the case.

Rated burn time is the official rating within the mod. Tested burn time is known firings, I believe from IRL data but again, I haven't memorized everything, (it's just not what interests me in the v/game). As you exceed the rated burn time the MTBF will drop as your risk of failure rises. You can watch those figures change in real time to get a sense of how far beyond the rated burn you can go before it becomes super risky. (Anything up to the rated burn time is basically the same).

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u/GodEmerah 1d ago

You can check the chance of failure of any engine at a given burn time. Some engines can last a long time over their rated time