We know that there are three major Deep Space Network (DSN) sites on Earth, roughly $120^{\circ}$ apart, to communicate with space probes in deep space continuously. All the data from the three DSN sites must somehow be transferred to NASA. If a signal is transmitted to the spacecraft then data must flow from JPL, NASA to the corresponding station which can be used to relay. How is the data from the three DSN sites transmitted to JPL, NASA or vice-versa? Is that through a guided medium like optic fibres or is that through a un-guided medium like satellite communication, or is that something else?


1 Answer 1


NASA facilities including the DSN are connected to each other via the NASA Ground Communications System (NASCOM). The network uses cables, microwave links and satellites. Each facility is connected to the network both by cable and via satellite.

(Source: Haynes manual for Voyager 1-2, page 106)

NASCOM is now part of the NASA Integrated Services Network (NISN). NISN still maintains two networks: a standard TCP/IP network for office networking, and a separate network for mission communications that primarily uses dedicated circuits.

  • $\begingroup$ Thanks for your answer. How did they manage to connect three DSNs that far using a cable? It's surprising for me. $\endgroup$
    – Vishnu
    Oct 23, 2019 at 7:10
  • $\begingroup$ "...it's possible the organization has been renamed and/or restructured" and that fiber has replaced microwave links? $\endgroup$
    – uhoh
    Oct 23, 2019 at 7:12
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    $\begingroup$ @Intellex Cables are routinely used to connect continents (i.e. they span the width of the Atlantic and Pacific). Long cables are a solved problem. $\endgroup$
    – Hobbes
    Oct 23, 2019 at 7:14
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    $\begingroup$ I haven't found details yet, but it'll be mostly cables, with satellite backup. Satellite transmission has lower bandwidth and longer delays (because the sat is in geostationary orbit, you get a path length of 72,000 km, instead of the ~5000 km for a Transatlantic link). $\endgroup$
    – Hobbes
    Oct 23, 2019 at 7:44
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    $\begingroup$ for more info on long cable technology: en.wikipedia.org/wiki/Submarine_communications_cable $\endgroup$
    – Hobbes
    Oct 23, 2019 at 7:45

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