Letter from Thomas Gold to Dr John Naugle, Associate Administrator, Space Science and Applications, Code S, NASA Headquarters, Washington DC States that a large part of the genuine scientific utility of space instruments results from devoted investigators studying results long after the vehicles have made their first impact. Whether or not any vehicle should be turned off should therefore depend very much on the interest and competence of investigators analyzing the results. Gold thinks the case made by Ken McCracken in his letter to Naugle of 14 january 1971 is a strong one. He hopes it will indeed be possible to maintain these vehicles in service. 8 June 1971