How can NASA build communication systems capable of sending and receiving information through distances of space that dwarf the size of the Earth many times over?

287 views

How can NASA build communication systems capable of sending and receiving information through distances of space that dwarf the size of the Earth many times over?

In: Technology

They use giant dishes and a lot of signal filtering. The farther the system they are communicating with, the slower the bit rate they can communicate at. Your home internet connection is probably in the tens or hundreds of millions of bits per second. Extremely distant probes have much slower rates. The New Horizons probe had a connection speed of approx. 38 thousand bits per second when it went near Jupiter. By the time it was at Pluto that rate had dropped to 1 thousand bits/second.

They use some of the worlds biggest parabolic antennas. That means that they can send out very powerful signals from the Earth in a very tight beam so that almost all of the energy hits the target spacecraft. Similarly when they are receiving signals they will collect all the energy over the huge area of the antenna and only collect the energy coming directly from the spacecraft. It also helps that they have dedicated frequencies that nobody else is allowed to use so that they do not accidentally receive a domestic radio station or someones wifi. But even this may not be enough. They usually have to slow down the transfer rate to reduce errors, the longer you spend sending out each bit the more likely you are of receiving the correct value. There are also a lot of error correcting codes used such as sending all the data in double or even triple to make sure it is received properly.

The trouble with communication on earth is that the earth gets in the way. Out in space, there is little to nothing to block or alter your signals.

Distance becomes a problem in its own way but that can be dealt with by aiming your signals better and with sending signal codes that are easier to receive and remove errors from.