NASA's international satellite projects and the significance of Helios

An overview is presented concerning the basic NASA ground rules, guidelines, and practices associated with the establishment and conduct of a NASA international cooperative project. The Helios project is the most expensive and scientifically most significant of all of the NASA unmanned cooperative satellites considered. An agreement signed in June 1969 provided for Germany to develop a flight spacecraft with both American and German scientific instruments aboard that would be launched by the U.S. on two separate missions toward the sun. Details of the Helios mission are discussed along with aspects of spacecraft design, subsystem characteristics, and the scientific experiments.