1. Explorer program announcement of opportunity : university-class explorer and missions of opportunity Publication/Creation: [Washington, D.C.] : National Aeronautics and Space Administration, [1998] Resource Type: Book Access & Availability: Loading
2. Explorer program, medium-class explorers (MIDEX) and missions of opportunity Publication/Creation: [Washington, D.C.] : National Aeronautics and Space Administration, [2001] Resource Type: Book Access & Availability: Loading
3. Explorer program, medium-class explorers (MIDEX) and missions of opportunity Publication/Creation: [Washington, D.C.] : National Aeronautics and Space Administration, [1998] Resource Type: Book Access & Availability: Loading
4. Explorer program, small explorers (SMEX) and missions of opportunity Publication/Creation: [Washington, D.C.] : National Aeronautics and Space Administration, [2003] Resource Type: Book Access & Availability: Loading