Orbital mechanics and risk

Finn Shewell
2 min readMar 4, 2021


When I think about risk, I think about gravity assists.

A gravity assist is the act of using a planetary body to either speed up, slow down, and/or change the direction of a space craft. If you’re not careful though, you’re going to do all three — with the end result being a pretty speedy impact with whatever planet you’re trying to slingshot around.

Why do I visualise risk as gravity assists? Because it’s a useful heuristic — and it could be useful for you, too. I’m not the most quantitative guy — I love seeing the effect that changing one thing can have on another, and I love making small numbers big, but show me an algorithm or a risk model and my eyes glaze over. As such, I find it useful to visualise my thinking around the risk any given action has.

To figure this out for yourself, you need to ask 2 things:

  1. How likely are we to turn into a splat on the planet?
    In other words — how likely is it that this thing we’re trying to do breaks everything and results in whatever we determine failure to be?
  2. How quickly will we be going if we do escape orbit?
    What’s the likely net result of whatever it is we’re trying to do? Is it going to be enough to accomplish goal X?

From there, it’s about figuring out if what you stand to gain is worth leveraging what you stand to lose.

For example — would you accept a 10% chance that you’ll get ‘pancaked’ in order to speed yourself up by 12%? What about those same odds to triple your speed?

How close are you willing to get to the surface of your planet in order to get to where you’re going?

That’s always the question you need to be asking — and then you need to be comfortable with nearly burning up in the atmosphere — if that’s what you’ve committed to do.



Finn Shewell

👨‍👩‍👦‍👦 I help people work together