The UNSC Silver Star is an award given to UNSC soldiers. The Silver Star is awarded for gallantry and bravery in action against an enemy of the UNSC not justifying a higher award. It may be awarded to any person who, while serving in any capacity with the UNSC military, distinguishes him or herself by extraordinary heroism. It is one of the highest citations, below only a handful of others, such as the Medal of Honor and the Colonial Cross.
NOTE: It has not yet been seen on the uniform of a soldier in a Halo game, but in much likelihood, if it is seen, it will be a duplicate of its modern day counterpart.