two-way non-coherent mode

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A means of sending data from a spacecraft using an on-board oscillator to generate a downlink frequency. Normally, a coherent (consistent) mode is used for communications, whereby a spacecraft generates a downlink coherent to a strong uplink generated from a ground station. In contrast, in the event that a spacecraft receives a corrupted uplink, the TWNC (pronounced ‘twink’) creates its downlink signal using the on-board oscillator. For example, TWNC is used when a spacecraft is ‘hidden’ behind a planet in relation to the position of the ground station.

Subjects: Astronomy and Astrophysics.

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