Ah, lighting. There really is no specific method for producing good lighting other than trial-and-error. It sounds like you might just need to check if the lights are too close to the subject. Sometimes it helps to just change the light to a "Distant" type light.Shadows can be modified by simply double-clicking the light in the Object Manager. Maybe you just overlooked it.
Ah, there is one lighting technique I just remembered, though, called the "three point" light setup that might help. It's usually used for indoor environments and I haven't really tried it on a space shot like this. Basically, you have a key light above and to the side of the subject, a slightly dimmer fill light below and to the other side, and a back light behind the subject. I'll try to find a better explanation of this and return momentarily.