As many of you are aware, Mars Explorer is powered by Unity 3D.
Unity Technologies released Unity 2.6 today - and with it, an incredibly exciting new pricing structure for the independent dev version of their development system: Free.
I have petitioned for this move for some time, and nothing could have pleased me more than it's adoption.
You can now all join me on the path to becoming a successful 3D developer - and you don't need to invest anything but yourself. Serving in the contexts both of a serious tool and a delightful educational system, I can highly recommend Unity!
P.S. Over the coming weeks, I will be fine-tuning my freely available Mars Explorer Unity package
as a gift to beginning developers. I will also be providing a turn key system for converting detailed worlds designed directly inside the super powerful Unity editor into Mars Explorer compatible Whirld files. Stay tuned :)