Last October, after seven months of silence due to a major upgrade of the 70m wide radio antenna located in Camberra, NASA sent a set of commands to a 43 year-old spacecraft, Voyager 2. Billions of miles from earth since its launch in 1977, Voyager 2 acknowledged it had received the call and executed the commands without any issue. Interesting for sure - but what is the significance of this to power engineers?
Although often considered as the last cog in the wheel by system designers, in truth the power supply is probably one of the most important parts of their equipment. From the thyratron tubes used in the type REC-30 power rectifier to supply HV power to teletype teleprinters in 1930, through to the latest Wide Band Gap semiconductors. Without curiosity and passion, power designers would not have made a lot of things possible. Voyager 2 is a good example of that, but who remembers what happened in the late seventies and early eighties within the power industry and how leading power engineers changed the face of our industry?
Back in time
Launched on August 20, 1977, Voyager 2 was powered by a Radioisotope Thermoelectric Generator (RTG) that turns heat from the decay of a radioactive material into electricity. The generated voltage is regulated and distributed to the 14 scientific equipments and to the master control board. The overall power system has been designed to accommodate the RTG and despite the schematic being kept secret, a brand new technology was mentioned called ‘switching power supply’.
Known since 1930, switching power supply principles have been explored by power designers for decades with the aerospace industry with NASA being the driving force in research and development. Considering the astronomical cost of a launch, and also the lifetime of space probes and satellites, space power designers sought for lower weight, higher energy efficiency and compactness.