On April 13, 1969, NASA launched a new weather satellite called Nimbus 3.
This was the third in a series of second-generation research and development satellites NASA launched to test new technologies for weather forecasting.
Nimbus 3 had an infrared spectrometer that allowed it to record temperatures throughout the Earth’s atmosphere.
It could also detect electromagnetic radiation in a whole spectrum of wavelengths, which helps scientists determine the structure of the atmosphere.
The satellite also had cameras that provided real time images of cloud coverage.
Nimbus 3 launched on a Thor-Agena rocket from Vandenberg Air Force Station in California and entered a polar orbit.
Source: https://www.space.com/39251-on-this-day-in-space.html