Eli5: Voyager II


With the Voyager II spacecraft millions of miles from earth and continuing on, how are we able to send/receive data from deep space?

In: 28

There’s a number of factors involved in allowing the Voyager probes to be able to communicate out so far.

**very large antennas** – Voyager uses a antenna 14 feet in size, and the opposite antenna on Earth is 34 feet in size. Which is 10-30 times the size of your usual satellite dish.

**directional** – The antennas are aligned to be pointing directly at each other, which increases the chances of relieving a clear signal

**interference** – The radio channels used by Voyager are very quiet by human standards, this cuts down on interference. If we had used a common band like 2.4ghz for example there would be so much interference that we couldn’t hear Voyager.

**power** – the radios use a lot of transmit power. The radios on Voyager are 23 watts compared to the 3 watts of the average cellphone. But even this is pretty weak Big radio stations on Earth transmit at tens of thousands of watts and still fade out quickly. This is the benefit of transmitting through empty space, the signal is less likely to degrade. The transmit antenna on Earth however is several tens of thousands of watts to make sure Voyager can here us.

As for receiving from Voyager it helps a lot that we know exactly where Voyager is, and what it’s transmitting.

Even though there’s some good answers here, I think people are failing to address something – the messages sent to and fro travel at *almost the speed of light*! So even if Voyager 2 was 300,000 km away, it would still only take 1 second for its messages to reach us, and another second for our messages to reach it. This can reasonably go on for YEARS!