After reading my Earth Day 2020 post you might be wondering how on “Earth” NASA keeps track of all the probes way out there in space. We all know that boats, cars, and airplanes all need constant course corrections. So, how is this done? It all happens at Cal Tech’s Jet Propulsion Laboratory in southern California where I had the opportunity to visit in 1986. In fact, I was there just as the very first close-up images of Halley’s Comet taken by the deep space probe, Giotto, were being displayed on the internal monitors. How neat was that! These would later be cleaned up before sending them out to the media.
Later, our guide met us and showed us around the facility’s technical equipment, including the mission control room, as you can see in the link. Looking much like an air traffic control radar room, here the controllers monitor the probes, not with radar but with radio communications. Just as with all the manned spaceflight missions, there are three antenna stations located at Goldstone, Southern California; Madrid Spain; and Canberra, Australia. Together, these enable constant communication with the probes as the Earth rotates.
Communication is a bit tricky since commands have to be issued well ahead of time, depending on how far out the probe is. Commands also have to be timed within micro (or Nano?) seconds so any course corrections don’t send the probe off the adjusted course. This has to be done by computers since they are much better than humans at dealing with microseconds or less. There is, however, a digital atomic clock (based on the radioactive decay rate of Cesium) on the wall for human reference. It has an accuracy of +/- 1 second every 3 billion years, so you don’t have to reset it too often.
During this time of growing distrust of science and more acceptance of superstition and unsubstantiated beliefs, Carl Sagan’s Baloney Detection Kit might help you discern what’s possibly real.
Stephen Fielding Images 