A Brief History of the United States Astronomy Spacecraft and Crewed Space Flights

The early successes of Sputnik and the Explorer series spurred the United States to develop long-range programs for exploring space. Read a history of some of the spacecraft that NASA has used to study the universe.
A Brief History of the United States Astronomy Spacecraft and Crewed Space Flights [328KB PDF file]
This history of U.S. astronomy spacecraft is part of the Space-Based Astronomy Educator Guide.