KAROLINSKA INSTITUTET STOCKHOLM 60 November 20, 1964 BAKTERIOLOGISKA INSTITUTIONEN Professor Joshua Lederberg Department of Genetics Stanford University Medical Center Palo Alto, California USA Dear Professor Lederberg: A few days ago I was very happy to receive a letter from the U.S. stating that: "As a sequel to the COSPAR meeting and the establish- ment of a criterion for the probability of not hitting Mars with an unsterilized probe, NASA has reviewed carefully the probabilities of a guidance error for this spacecraft and has concluded that it meets the COSPAR criterion. I do not think that this has been given any great publicity due to the general uncertainty of the engineering estimates involv- ed, but you will be glad to know that the NASA people did indeed take the COSPAR recommendation to heart. This has been discussed in detail with our Space Science Board", Considering your valuable assistance when I prepared the background document on which the ‘specialist panel acted in Florence, I thought that you might be interested to know that the international effort may have been helpful. I mention this as an argument for this sort of activity, hoping that you will consider favourably a suggestion from professor A. Tiselius, to join in a Consultative Group con- cerned with the potentially harmful effects of the develop- ments in the biological sciences, just as the COSPAR Group is concerned with the consequences of space research. Per- sonally I think that the former group will be of infinitely greater importance. Will you be in Stanford in March 65 when I expect to be in California for a few weeks ? Best personal regards. SaAn Urs ,y — oo, Ve C.