Still working after all these years

There's a ticker on the NASA site which tells you how far away from the Earth the satellite is: when I looked just now, it was 18billion km and counting. At that distance, communications with the probe take 34hours to reach their destination. The spacecraft – Voyager 2 was launched on a similar mission in September 1977 – are three axis stabilised systems that use celestial or gyro referenced attitude control to the high gain antennas pointing towards the Earth. Perhaps the most stunning thing about Voyagers is they feature an eight track digital tape recorder. The Flight Data Subsystem (FDS) configured each instrument – many have now been shut down – and controlled their operations. It also collected engineering and science data and formatted the data for transmission. The tape deck, meanwhile, continues to record data from the plasma wave subsystem. Data is played back every six months. Uplink communications is via S-band (16bit/s command rate) while an X-band transmitter provides downlink telemetry at 160bit/s normally and 1.4kbit/s for playback of high rate plasma wave data. All data is transmitted from and received via Voyager's 3.7m high gain antenna. That 1970s technology continues to work is a something of a miracle, bearing in mind many people's experience with devices built much later.