Nasa's Small Explorer Program

Abstract

Substantial publicity surrounds NASA's major scientific space missions. The Voyager interplanetary probes enthralled the public as they swept past the outer planets. The Hubble Space Telescope continues to attract great attention because of its ambitious objectives and large cost as well as its technical difficulties. NASA's deep space missions, such as Pioneer, Viking, Magellan, Galileo and Ulysses, and its “moderate” missions such as the Cosmic Background Explorer are further examples of large, longterm projects. Near-Earth spacecraft like the recently launched Gamma Ray Observatory and the many satellites of the planned International Solar Terrestrial Physics program also cost hundreds of millions of dollars. Indeed, with the attention given to programs involving humans in space—Space Station Freedom and the Manned Mission to Mars, for example—it might appear that NASA has only “big ticket” space missions.