On Crawford Hill in Holmdel, New Jersey there’s a collection of old scientific radio antennae which were built decades ago but are now abandoned. One of these is a Hogg Horn Antenna built for project Echo, the first proper demonstration of realtime satellite communication. It needed to be large and exceptionally sensitive because the satellite was a passive reflector rather than an active relay.
This sensitivity later lead to it being used as a scientific instrument to study the skies in radio waves, but the scientists using it, Arno Penzias and Robert Wilson struggled to eliminate radio noise which was creeping in. They worked hard to get rid of this until they eventually discovered a scientific explanation for this and ultimately were credited for their work in discovering the cosmic microwave background radiation.
The site is currently abandoned, but the horn antenna is registered as a historic place, hopefully this will result in the preservation of the antenna for future generations.
You can read a lot more about NASA’s balloon satellites in this book about NASA’s history: