Why aren't you playing Kerbal Space Program yet? It's free

I have purchased KSP. I'm toying with the lander legs now, which are a sorely needed addition since there are not things to land on.

 

I've downloaded v0.16. It's $18 to purchase now, but still worth the money if you're into these things, especially since that gets you access to future versions. Kerbin now has two satellites (Mun and Minmus) and the game incorporates plugins now. A highly popular one is Mechanical Jeb (Mechjeb) which provides an auto-pilot for most common maneuvers, and a wealth of data about your craft, your trajectory and the body you're orbiting. You'll find data you didn't even know you wanted to know.

Remember kiddies: rockets don't explode. They just undergo rapid unplanned disassembly.

 

Another new feature of 0.16 (or 0.15 actually) is persistent missions. You can now launch a vehicle, put it in orbit, then return to the space center and the vehicle will remain where you left it. This applies to failed missions as well as successful ones, and care must be taken with staging to avoid cluttering the sky with debris.

My current project involves launching a series of satellites (available via plugin) to map the surface of Kerbin and establish a communications network. I have two mapping satellites currently; one is in a 400 km polar orbit to provide a low-res map of the entire surface, while the second is in a low-kearth 30 degree orbit to provide high-res data around the equator. I also have two of a planned six communications SATs in keostationary orbit. After that, I'll send map SATs to Mun and Minmus, followed by manned missions.

Version 0.17 will provide new planets to explore, which promises to be very exciting.