The NASA Exceptional Service Medal is an award granted to U.S. government employees for significant sustained performance characterized by unusual initiative or creative ability that clearly demonstrates substantial improvement in engineering, aeronautics, space flight, administration, support, or space-related endeavors which contribute to NASA programs.

The NASA Exceptional Scientific Achievement Medal was established by NASA on September 15, 1961, when the original ESM was divided into three separate awards. Under its guidelines, the ESAM is awarded for unusually significant scientific contribution toward achievement of aeronautical or space exploration goals. This award may be given for individual efforts that have resulted in a contribution of fundamental importance in this field, or have significantly enhanced understanding of this field.