the orbital inclination of the plane of the spacecraft's orbit to the Earth's equator was of 89.80°. The spacecraft's axis of rotation at launch was inertially fixed in its orbital plane, directed towards a constant right ascension and declination, and nearly parallel to the Earth's equatorial plane. Results In 1992, Dr. James Van Allen (the Hawkeye Project Scientist) and the other Hawkeye principal investigators provided the National Space Science Data Center (NSSDC) with the high resolution digital data (referred to as Master Science Files) from Explorer 52 (Hawkeye-1). Recognizing the uniqueness of these data, the NSSDC has placed the entire Hawkeye data set in its on-line archive. See also Explorer 20 Explorer 25 Explorer 40 Explorer program References External links NASA's Explorer Missions Satellites formerly orbiting Earth Explorers Program Spacecraft launched in 1974