Hi. Can anyone tell me the absolute altitude record for an unmanned balloon? I have a reference that the Winzen Research Balloon reached 170,000 feet (51,816 metres) in October 1972:
http://web.bryant.edu/~history/h364proj/summ_99/riel/timeline1900.html , but the FAI say they are unable to confirm it, as they did not ratify records set by unmanned aerial craft at that time.
Thanks in advance