In January, 1961, Marshall Space Flight Center (MSFC), now called NASA, established an instrumentation site on the northeast corner of Green Mountain (Recreation Point) for use in developing and testing space vehicles antenna. Source: Marshall Star
More information
https://history.msfc.nasa.gov/vonbraun/documents/VB_WN_196410.pdf
https://history.msfc.nasa.gov/juno/Juno_II_Explorer_Articles.pdf