• Question: How do you collect data from a satellite?

    Asked by cbaxter12 to Adam, Alexander, Aron, Jess, Neil on 7 Mar 2014. This question was also asked by hannahmaereed.
    • Photo: Neil Bowles

      Neil Bowles answered on 7 Mar 2014:

      Generally, it gets radioed back to Earth and collected by ground station, kind of like a large sized satellite television dish you see on people’s houses. For spacecraft further out we use bigger dishes, with three in locations around the world to give 24 hour coverage. When we talk to the Cassini spacecraft in orbit around Saturn for example, commands get sent by radio from a big (~70 m) diameter dish in the California (part of NASA’s Deep Space Network, ESA has something similar) and picked up by the spacecraft in orbit around the planet Saturn. Saturn is so far away it takes 80 minutes or longer for the radio waves to travel from Earth to the spacecraft. And the another 80 for us to hear a response…

    • Photo: Jessica Marshall

      Jessica Marshall answered on 10 Mar 2014:

      We have to be in contact with the satellites for several reasons – we need to know where it is and how it is behaving. We also need to be able to send it commands, such as turning around. So, for those sorts of commands we use a low or medium performance (gain) antenna and communicate via radio waves. For large amounts of data, we have big dishes, or bigger antennas which we point at a region of the Earth whilst transmitting the data. On the ground, these signals are picked up by dishes too, they can be the dishes on the sides of peoples houses (collecting satellite TV), or for very weak signals coming from much further away, such as a satellite around another planet, we use the big ground stations which are positioned around the Earth (see Neil’s answer).

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