27/6/2011 update
I've added a sort of reverse-collectible. As you explore the asteroid explored areas are marked with a little cross. I feel this encourages exploration and aids localisation in an otherwise featureless environment.
Let me know what you think. As ever, I will continue to ponder the future of this project. I am growing to love its non-game-ness.
The crosses certainly help keep oriented, the only other thing that would be nice would be some co-ordinates in the corner so that players could talk about areas that they found in different asteroids. Noctis did this on a somewhat larger scale, but similar concept.
Also, have you seen this game?
Space Game : Mujakwi It's like you both started with the same concept, then took it completely different directions...