Small Explorers Program (SMEX)
The Small Explorer program (SMEX) is an effort within NASA to fund space exploration missions. Extending the larger Explorer program, it was started in 1989.
The first set of three SMEX missions were launched between 1992 and 1998. The second set of two missions were launched in 1998 and 1999. These missions were managed by the Small Explorer Project Office at NASA's Goddard Space Flight Center (GSFC).