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Comment by jonmrodriguez | Hacker News Reader

I set up some really crazy orbits :-D

One of those birds is in a circular orbit one bird-height above the ground!

Another is in a very eccentric orbit that skims the ground when it comes to the bottom-right of the screen, then almost grazes the asteroids in the top-left.

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The one thing I don't like is that this game's physics don't seem to behave properly. In real life (and in Kerbal Space Program) you burn at apogee to increase the height of your perigee, or burn at perigee to increase the height of your apogee. But that rule doesn't seem to apply to Flappy Space Program, making this game anti-educational. :-(

Hi, dev here. I certify you that the physics are OKish. You should burn at apoapsis to circularize, etc. What prevent you to realize this is that it's hard to know when you're at apo/periapsis, so you're burning with some vertical velocity and that changes how your orbit change. Anyway, this game was really a joke, if you want an educational game, I've also made this: http://deltav.corpsmoderne.net/

+1 for the delta-v game!

Here's a reddit thread about the game with a "high score list": http://www.reddit.com/r/gravity_games/comments/1fks9v/oc_del...

If anyone wants to test out their orbital mechanics skillz, you can try to beat my unofficial world record, a grand tour of the Jovian moons:

http://deltav.corpsmoderne.net/game.html?s=Jupiter&prg=QlVST...

I took on your challenge, determined to do it from scratch with no copying, and I have this:

http://deltav.corpsmoderne.net/game.html?s=Jupiter&prg=QlVST...

More points, due to orbits of and impact with Jupiter, but slightly less efficient and elegant overall I dare say - some burns not really at peri-/apo-apsis, and my orbits are generally higher and less circular. Kudos also for motivating me.

This game is super fun even though it's a joke. Might I suggest that once your bird has left the cloud layer, all subsequent burns are purely prograde? (To deal with the edge case where the bird reenters the atmosphere, the rule could be that all burns are purely prograde if the bird has ever left the atmosphere). I think a lot of people will play this game and the Hohmann Transfer concept would be a cool thing for them to be able to take away.

You might want to switch from Eulerian integration to Verlet for more stable orbits. http://gamedev.stackexchange.com/questions/15708/how-can-i-i...

> I certify you that the physics are OKish

A++++ would physics again

it is damn hard to for me to escape the close orbit bird. I have managed that feat a few times but I like getting four out there and seeing how long before they intersect.

I get a serious "solar system" vibe instead of satellite vibe when playing this game, as in how would comets move through a system and such but on a simplified scale

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