Friznit

This is a common question because it's a weird mechanic but it's working as intended. The "overheat" is used to limit drill output. Basically, each drill will only put out 100% stuff. 1 bay online = 100% stuff, heat looks normal. 3 bays online = 33% stuff each, with "overheat" used to artificially limit efficiency. You only need sufficient cooling for one bay's worth of heat and can ignore the rest of the numbers.

Use fuel lines set to docked mode.

Yes you can do both. I've done it in every version since 1.4 and it's been working fine though typically I'll complete the first contract before taking the second chap on his tour.

Really getting into using Solids. They're cheap and very effective for routine launches.

If in doubt, it was probably Zorg (it was Zorg) Though like me he favours the Near Future Stubber in LOX Augmented mode. It needs to be clipped up into the S-IVB engine mount to fit the interstage but it looks just fine.

CobaltWolf made me do it! Probes Plus and BDB are a match made in heaven. More payloads! https://github.com/friznit/Unofficial-BDB-Wiki/wiki/Satellites. I've knocked up a few historical launch vehicles as well for a bit of fun. I'm sure there are plenty more probes that can be built with Probes Plus, but I've mostly focused on the US stuff to complement BDB. I have all the craft files so I can bundle them up and stick them in a github ticket if you would like?

It's fixed in the dev version of BDB. If the popup bothers you enough you can try using Dev BUT...it's at your own risk. Dev is for dev and testing, so you won't get any support if it breaks stuff!

I believe there is some work in progress in B9PS which should hopefully unlock the ability to support multiple fuel types on an engine, which will be neater than the current workaround (i.e. hacking around the multimode engine feature). In the meantime, the easiest approach is to knock up a quick MM config to replicate the engine with +PART and add your fuel of choice.

They way I've always reconciled it is that your kerbs need a home base at either end of the journey but are reasonably content to be cooped up during transit. This encourages building orbital transit stations, gateways and planetary bases at the destination if you intend to stay long term. Also on very long trips, supplies are prohibitive enough that cryogenic freezing is often a requirement anyway.

During extensive research for the BDB Atlas revamp, the team stumbled across some archive footage showing that things don't always go according to plan Images courtesy of @Zorg

Barring the usual caveats, yes absolutely use the Dev branch. Fire up a Titan and glory in its magnificence. It'd be pretty cool to see a mix of KSPIE and BDB comes to think of it. Hmmm, alt history thonk...

Sounds like an idea for the State Funding mod! BDB solids are hella fun. I never really used them before other than for Moar Boosters™ but there are some truly bonkers design concepts around. Just when you think you've come up with something utterly crazy, you'll stumble across an old NASA doc with something even better. @ZorgUSAF sending up a completely peaceful meteorological observation platform using a Russian probe core? Delicious irony.

Sorry, I meant Explainer...

Also grab MKS explorer if you want to see the underlying calcs