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Comment by dnautics | Hacker News Reader

have you ever done course corrections in KSP? A tiny nudge early on is enough to make a huge difference farther out!

Yup. And if you've ever done maneuvers manually in KSP, you know that a tiny error in your nudge early on - e.g. hamfisting the throttle, or being a little too late in mid-maneuver staging - leads to a huge difference farther out, which you then have to correct, wasting precious ∆v :).

I'm very much impressed by the control precision of real-life space probes.

Check out the crazy journey Rosetta took on the way to 67P/Churyumov–Gerasimenko:

https://commons.wikimedia.org/wiki/File:Animation_of_Rosetta...

Wow, I actually had no idea; how is this all pre-planned, does somebody at NASA just put "67-P/Churyumov" into a "Orbital Maneuver Planner" and let some computers crunch the possible paths out? Or does someone actually sit down and come up with the possible sequence of orbital assits (to later verify with a computer) with a pencil and paper?

Just a correction, but it's a project of the European Space Agency, not NASA.

It's a combination of both. They have tools that help worth the trajectory calculations, but they have to manually decide on the basic layout of the path to take.

There is a very interesting interview with Pablo Munoz from the Bepi Colombo team about flight dynamics on the Omega Tau podcast that explains this: http://omegataupodcast.net/295-bepicolombo/

The other interviews on the same episode are also worth listening to. In fact, the entire podcast is great.

Common orbits are solutions to the two body problem, but Shane Ross has a few videos on youtube about chaotic solutions to the three body problem, allowing objects to move in very complex orbits with very little fuel. This has been used for a few missions as I understand it, the math is WAY above my head, but the video is still quite watchable with lots of cool orbit animations:

https://www.youtube.com/watch?v=FwHDEB1VS_0

Also the path BepiColombo is taking to Mercury:

https://en.wikipedia.org/wiki/BepiColombo#/media/File:Animat...

> a tiny error in your nudge early on - e.g. hamfisting the throttle

And this is one of the many reasons why these machines are horrendously expensive - they are incredibly precise.

ah yes, you are commenting on the precision not on the magnitude of the displacement!

I think everyone with an interest in spaceflight should play Kerbal Space Program. It gives you a sense of scale, both of space and time (luckily you can fast-forward to 100.000x), and also teaches you the basics of making orbital trajectories and correcting them, landing on planets/moons with different gravity... I'm really glad to have played it!

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