Being a parent has its memorable moments. For me, one of these is just where innocent curiosity can lead a six year old. Being asked, while out walking in the bush, what the magpie just said (because Dad must be able to understand birds even if I can’t, right?) will stick with me for a long time.

Communicating with young kids is something I find an enjoyable challenge. They don’t have the same set of primers an adult would have if we discussed a particular topic, so it forces me to break things down into first principles, use simple language, and often accept that the explanation that best gives the sense of the answer is what they’re likely to be able to digest and use, even if it’s not entirely accurate.

One of the topics that still prompts curious questions is how the moon, sun and so on stays in the sky. Explaining orbital mechanics to a six year old with notions of swinging things around themselves sounds obvious, but they’re not going to easily make the connection between a bucket of water and the moon. Try to explain transfer orbits and, well, despite many evenings watching space programme documentaries with the old man, their eyes glaze over and ‘Yes, Dad’ and they’re off to draw on the walls or something.

Heck, until recently I don’t even think I really had that good of an understanding of transfer orbits.

Enter Kerbal Space Programme, a space simulation / sandbox I stumbled across recently. Essentially a rocket science lab, in its free demo form you can build various simple rockets, launch them into orbit and perform numerous orbital manoeuvres using a handy orbital planning system. Suddenly, burning at periapsis to raise your apoapsis can be demonstrated practically, rather than just with formulae and diagrams on the whiteboard; conserving fuel, understanding ISP and delta-V or even managing space junk becomes something you can experience interactively.

And accidentally stranding your cute Kerbals in space leads to some interesting reflections on just how risky – and what an engineering triumph – the early era of manned space flight was.

Mind you, these days, while manned space flight is still far from routine, at least it’s progressed to the stage where it can serve as a venue for a music video. You can’t do this in Kerbal Space Programme…

In other news, hopefully things are returning to normal around here. Maybe I’m reaching my own apoapsis – and pretty soon I can start back down and get back into it.