Small Explorer (SMEX) Program
- Includes information about the small explorer class of missions in the explorers program, including SAMPEX, FAST, SWAS, TRACE, and WIRE.
- http://sunland.gsfc.nasa.gov/smex/index.html

NASA's Explorer Missions
- The National Space Science Data Center (NSSDC) provides a summary list of all Explorer missions with links to mission overviews and data.
- http://nssdc.gsfc.nasa.gov/multi/explorer.html

Explorers Program
- Goddard Space Flight Center provides frequent flight opportunities for world-class scientific investigations from space. Includes program history, current missions, and upcoming opportunity schedule.
- http://explorers.gsfc.nasa.gov/