What type of onboard recorder stores high-rate Voyager plasma wave data?

A digital tape recorder stores Voyager’s high-rate Plasma Wave Subsystem data.

Each Voyager spacecraft carries a single eight-track digital tape recorder, or DTR, as part of its data-handling system. The recorder was needed because some instruments could generate data faster than the spacecraft could transmit continuously across the enormous distance to Earth.

The Plasma Wave Subsystem records measurements of electric-field fluctuations and plasma waves. Voyager’s Flight Data Subsystem organizes instrument and engineering information, while the DTR temporarily stores the highest-rate plasma-wave observations for later playback. Historically, the stored data were transmitted during scheduled communication sessions, sometimes at intervals of about six months.

“Digital” distinguishes the device from an obsolete punched-tape recorder or magnetic drum. “Solid-state recorder” is also a tempting modern answer, but it was not the storage technology installed on the original Voyager spacecraft. Their computing and recording hardware reflects 1970s engineering, yet it has continued operating across billions of kilometers and decades of radiation exposure.