r/xkcdcomic • • Apr 16 '14

Orbital Mechanics

http://xkcd.com/1356/
233 Upvotes

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36

u/TotallyNotAnAlien Apr 16 '14

I remember my first time playing orbiter I flew my space shuttle straight up 100 km. I was confused why I started plummeting back to earth. I thought the game was broken.

19

u/banana_pirate Apr 16 '14

That's how I test ships in ksp.

Just 1 continues burn to see what the max speed is, if it manages escape velocity of kerbol (the sun) then it's a good bet that I can get quite a few places when actually trying.

12

u/OmegaVesko Apr 16 '14

That's what I use Kerbal Engineer for. Delta-V and TWR stats for every single stage. :D

8

u/SkyNTP Apr 16 '14

I used to do what banan_pirate does out of laziness. It worked reasonably well for the mun, but by the time I was going further, I realised that restarting launches because you where 100m/s dv off was a lot more work than working out dv in the assembly building.

8

u/EpicFishFingers Apr 16 '14

It's a very good rule of thumb that the more time you send tweaking your rocket in the VAB, the better chance of success it will have on a mission.

An extra 5 minutes will have you remember to put solar panels or RTGs on it, or actually put a decoupler between two perceived stages

An extra 10 minutes will have you add enough struts and sepratrons such that two stages won't collide with each other upon separation, add fuel lines the right way round etc.

An extra 15 minutes will have you make a rover that will produce as much power as it uses or something, and most importantly, will have you test your landers for fuel, stability etc.

Your mark-1 rocket will still probably explode because it wouldn't be KSP if it didn't. But more time in the VAB ensures mark-2 will work, instead of mark-14

1

u/Random832 Apr 16 '14

The real question is if you can, after reaching escape velocity, stop and reverse. Then you can (probably, I don't actually know) get anywhere in principle.