Odonian

That first Orion asteroid tug used NPU-500 charges, but I'm now using NPU-2500 charges successfully. Here is one such tug capturing a roughly 3 million ton asteroid. Acceleration with an asteroid grappled is practically nil.

I was having trouble with the most recent versions of Orion, too, but I managed to get it working again by installing the 2016.10.15.1 Constellation pack.

@RoverDude, I think you may have missed my question: what conditions have to be met for the "Vent Rock" option to pop up in an asteroid's right click menu? It doesn't appear when I latch onto asteroids with the Jaw and start the laser. I'm not sure if I'm experiencing a bug or have simply not brought along the correct ART components. I added ART to a clean install of KSP 1.2 and get the same problem.

Today I brought a 257,609 ton asteroid into a 5,000km orbit around Kerbin, using RoverDude's orion nuclear pulse engines and starlifter SAS rings to keep everything stable. The 1.2 autostrutting feature is fantastic, in 1.1.x this setup would have shaken itself apart or wobbled uncontrollably. I hope to build a refueling station into this asteroid, for an alternative to refuelling at Minmus without having to change inclination before the transfer from Kerbin. Also, I guess, I joined the forums (I've been lurking for around a year). Hi!

It's a lot of fun wrangling giant ART asteroids and bringing them into orbit around Kerbin using clusters of Project Orion nuclear pulse engines and starlifter SAS rings to keep everything from wobbling. The 1.2 autostrutting feature makes connections to asteroids a lot more stable, and I'm excited to play with asteroids again. Maybe with weldable Konstruction ports it will be possible to attach asteroids to each other, something which always summoned the kraken for me in 1.1.x, when the klaw or KAS attached docking ports had to be used to do this. I'm having some trouble with ART, though. None of the asteroids I grab with the Jaw have the option to 'Vent Rock'. Is there a specific combination of parts that need to be present in order for this option to pop up in the right-click menu, or is this a bug? Thanks!