Communications System

How does DS1's communications system work?

How do the instruments and sensors coordinate sending signals?

It is impossible for all instruments and sensors to transmit their data at the same time because of bandwidth restrictions, so they each send pieces of data in quick succession. If there is a known order in which these messages are sent, ground can then tell what measurement is being represented by where in the order it came.

This predefined order is an older solution to the problem of coordinating signals, and it is called time-division multiplexing. A very simple example might be to send, say, a zero followed by four numbers. The zero tells the scientists that this the start of the order, and then they would know that each following number represented a specific scientific instrument.

Newer spacecraft use what is called packetizing. In the packetizing scheme, a burst (or packet) of data is transmitted from one instrument or sensor followed by a packet from another, and so on, in nonspecific order. Each burst carries an identification of which measurement it represents so that ground can recognize it even if things are sent in no particular order. The Internet also works by using packets.

How is data put on radio waves?
What interferes with communications?
How often is DS1 in communication with Earth?

What kind of data is DS1 sending back?
What are high and low gain?
Why does communication get harder at greater distances?
How much data is DS1 able to transfer?
What components are where on DS1?

How is data processing managed?