When NASA launched the Nimbus-4 satellite 50 years ago, nobody knew the ozone layer over Antarctica was thinning. And nobody knew that chlorofluorocarbons (CFCs)—long-lived chemicals that had been used in refrigerators and aerosol sprays since the 1930s—were responsible.
Developed by a team led by NASA’s Donald Heath, BUV was the first space-based instrument to measure the total amount of ozone in the Earth’s atmosphere. “Don was really sweating the Nimbus-4 launch because his MUSE instrument on one of the previous Nimbus satellites ended up in the Pacific Ocean offshore from Vandenberg Air Force Base,” said Arlin Krueger, technical officer for the BUV science team. “That instrument was recovered from the ocean floor and sat on his filing cabinet for years as a reminder that risks are big part of the NASA experimenter’s life.”
Fortunately, the launch went smoothly. The BUV performed well and demonstrated a new way to measure total column ozone. This led to the Total Ozone Mapping Spectrometer (TOMS) on Nimbus-7. The ozone data it collected gave researchers baseline measurements that, in the mid-1980s, helped them recognize that a troubling hole in the ozone layer had opened up.