Continuous cosmic coverage

Other missions

The TDRS also facilitates communication and data transfer to and from other low-Earth orbit missions like Hubble, as well as remote bases like the Amundsen-Scott South Pole research station.

2. Relaying the message

The message from the ISS is received by the TDRS and relayed to a ground station on Earth.

4. Two-way link

When mission control need to contact the space station, the process works in reverse. Signals are sent to the ground stations, where they are transmitted to the TDRS for relay to the ISS.

3. Message received

The ground station relays the signal to the mission control centre it is intended for.

Global coverage

The TDRS satellites are positioned above the Atlantic, Pacific and Indian oceans.

1. Calling Earth

If astronauts need to contact mission control, their message is sent as radio waves to the nearest TDRS satellite.

Keeping in touch

Reliable communication between the ISS and Earth is vital for the everyday running of the station and the safety of the astronauts.

How does the TDRS network prevent communication blackouts?