The default skybox in Unity is a bit dull. The scene has a blue sky, brown terrain, and a horizon. This is not what space looks like! Let's start with creating a starfield skybox.

Wait, skybox? What is a skybox??? A skybox is a cube with a different texture on each face. Unity places your scene inside this cube, so no matter the game camera's direction, you'll see one or more textures rendered in the background.

In the Unity Editor Project tool window, create a new folder named "Materials", and then use the Create | Material context menu to create a new material. For Shader, select Skybox | 6 Sided. You'll see you now have 6 textures you must set, one for every face of the skybox cube.

You can drag and drop some of the textures in the Assets > StarfieldMaterials > Textures > Plain Starfields folder, and add a nebula from the Assets > StarfieldMaterials > Textures > SingleNeb folder.

Give your newly created material a name (you can do this in the Project tool window) so it's easier to find in your project.

This skybox material can now be used in the game scene. Use the Window | Rendering | Lighting menu to bring up the lighting settings, switch to the Environment tab, and set the Skybox Material to the starfield skybox you created. This should take effect immediately, already making the game scene look more interesting!

Now is also a good time to make two more changes to the scene. First, select the Main Camera in the Hierarchy tool window and set the Z value to "-20". This moves the camera to the back, showing more of the scene.

Next, select the Directional Light and set its Intensity to "2." This will give the scene a little more light and, later, nicer shadows on the asteroids.

With a space starfield in your game, you can add game elements such as the spaceship and asteroids. We'll cover that next.