What do you need to play moon base Alpha

Moon Base Alpha is a 100% free game made by NASA. It is available for download through Steam. You need a good, computer, (read the system requirements for more information on that), And you need to download a program called Steam. Steam is a program for gamers that allows them to download and play games, play with friends, make groups, and interact with others, its like a social network for gamers. Thats all you need. It may not work on all computers.
You can
find the system requirements on the bottom of the link:
I hope this helped, and Happy Gaming!