Interplanetary Grabbed By Steam Greenlight’s Gravity

Literally the dark side of the moon.

I daydream almost daily of turning myself into a projectile and rocketing myself across the sky. With a Half-Life gauss cannon in my hand, I think I could fire myself from my window to any destination within town.

Interplanetary does one better. It’s a strategy game in which you use the gravitational pull of planets in order to slingshot projectiles across the solar system, so that they smash against the fragile planets and moons of your opponent. It looks a little like DEFCON by way of Universe Sandbox. Since I wrote about it last month, the game has found its way on to Steam Greenlight, and there’s a new trailer below.

This is what space combat will really look like. Not photon torpedoes or space lasers, but heaps of rock and metal fired at supersonic speeds across the cosmos or between spaceships. Maybe there’s one such missile floating towards us right now, fired by some unseen civilization.

Probably not though. Probably you’ll have to play this game instead. Go vote for it on Steam Greenlight.


  1. Retro says:

    what does ‘supersonic speed’ in the context of an interplanetary game mean anyway..

    • Tyrmot says:

      Technically correct, though a bit of an understatement… ‘relativistic’ would be closer to the mark…

    • Gap Gen says:

      The web* says “The temperature of interplanetary medium is about 99,727°C.”** – this gives you a sound speed of around 30 km/s (you do sqrt (k_B.T/m_p), where k_B is the Boltzmann constant and m_p is the mean particle mass, which I took to be hydrogen’s mass because I’m lazy). This is about 3 times Earth’s escape velocity.

      ** Ha, they literally did just take 10^5K and convert it into Celcius. Reminds me of the joke where an archaeologist tells a reporter that a pot they found is five thousands years and three days old. When the reporter asks how they can be so precise, they answer that the lab told them it was five thousand years old three days ago.

  2. bills6693 says:

    The concept looks interesting and promising. I hope there’d be enough depth there to keep players around for a fair while.

    Looking at some of the shots you can see you have to manage resources, energy, and can build different types of weapon and defenses. They say on the greenlight page the weapons will have different variations too, so hopefully enough will be in there to make for a good amount of strategy. And if you could have 4 or more players in one game, it could really get hectic :)

    • SpinalJack says:

      (I don’t see it linked here so just to make sure)

      you can play the alpha right now by going to their steam page and downloading the game

      link to

      I hope they speed the game up a bit cos it takes a while to finish a game if you’re a bad shot like me

  3. Dozer says:

    Sigh. Must I do all your work for you.

  4. RuySan says:

    This brings me memories of Robert Heinlein’s The Moon Is A Harsh Mistress. Looks promising

  5. tyen says:

    I read this short story years ago and was just reminded of it by this.
    Had to dig around to find it. I swore it was written by Isaac Asimov, but I guess not.
    “The Gift of Mercy” by Anonymous link to

  6. KirbyEvan says:

    To be honest this is all I wanted to do in Planetary Annihilation and at least this game isn’t ridiculously expensive, so count me on the hype train.

    I mean hell, is there anything cooler than using gravity slingshots to murder enemies?

    I think not.