For Loading the Starfield Skydome into your Scene, simply Choose "File --> Append", then choose "World", then choose either "Starfield_Skydome_High_Resolution_16384x8192" or "Starfield_Skydome_Low_Resolution_8192x4096". The high resolution Version may consume about 450MB of VRAM, the low resolution Version about 150MB. Please note that this is a World Shader, not a Material (For More Information of a World Shader please see the Blender Wiki ).

The Settings are as follows: 

I recommend to adjust the Sky Texture first. Therefor you can set the Value "Blend Stars into Sky" to Zero. After Setting the Sky Texture and its Lighting Strength,

Set "Blend Stars into Sky" to 1. Then tweak everything of the appearance of the Stars. Finally, Set "Blend Stars into Sky" to a value higher than 0.8.

This Documentation is also packed into the Product file. It also can be downloaded here:

Documentation

    Credit annoucement of NASA regarding the commercial use of the Starfield:

"In general, our material is not copyrighted.  There are certain exceptions for the use of the NASA logo, the likenesses of people, and maybe the music we sometimes add, but none of those things apply in this case. We request, but do not require, a credit, and the credit can simply be 'Skymap by NASA Scientific Visualization Studio' "