Can someone explain me what this is/do?

[Delta_scientist]

Sorry if this has been posted before, but I couldn't find it anywhere.

Under the science tab when you build your rocket there are 2 things I can't find a reason for to have.

1: Kerbal engineering system and;

2: ER-7500 Computer flight unit

Are they good for anything?

[J.Random]

That's KER parts. To have KER in flight in career, by default you have to either have engineer on board or one of these parts. I believe it's configurable.

[LitaAlto]

If you have installed Kerbal Engineering Redux, you can attach those parts to your rocket in order to get detailed information about your rocket, in both the editor and during flight. This includes delta-V budgets, which makes it very worthwhile, but also details like aerodynamic conditions and orbital data.

Of course, if you also installed a script to place KER on every command pod and probe core, you won't need those parts to use KER.

[Delta_scientist]

Ah, make sense! Thanks for the answers.

[mrclucks]

In past versions I'll have a mod add KER to every pod, but I since there isn't one that I know of, I stick it between the layers of my command pod and whatever else I'm bring back to kerbin. I also use the same trick when I play with remote tech with the always on 300km omni antenna.

Both tricks haven't caused any problems with my crafts btw

[Chaos_Klaus]

In past versions I'll have a mod add KER to every pod, but I since there isn't one that I know of, I stick it between the layers of my command pod and whatever else I'm bring back to kerbin.

Well, that mod is obsolete, because KER actually has a partless mode that can be activated in its settings.