We communicate with the JUNO spacecraft with radio waves and radio frequencies.
But what we do is we send up commands or data to the spacecraft to tell it what to do
it in turn takes data and sends back what we call telemetry
...the way that we find out if there's a problem on the spacecraft in space is by monitoring our telemetry
and our spacecraft talks to us on Earth through the Deep Space network
the Deep Space network is a set of antenna that we use that are around the world in order to return data to us and to send commands up to the spacecraft.
We designed a lot of points on the spacecraft that tell us things like the state of charge of the battery what temperature things are at...
... and we look at that telemetry and monitor if the spacecraft is happy or sad and doing well or not
and we set limits on that so it will give us automatic alerts if something's wrong,
and so on the ground we can look at it and make sure every thing's okay, we can detect a problem that way.