My quarterly odd, hypothetical technical question…in around 1989, would either of the Voyager space probes have been able to detect if a spacecraft flew up close to the probe, using active sensors on it—er, that is, conventional radar or LIDAR—at least halfway carefully pried off the Golden Record, and then flew back off? And what would the ground controllers make
I mean, the Voyager probes obviously weren’t designed to detect and observe spaceships buzzing them, and with the communications delay, it’s not like the people at JPL would be able to watch what was happening in real time and turn the cameras on, or anything.
Hell, I don’t even know if any of the Voyager sensors would have even been turned on, if the probe wasn’t actually making a planetary flyby or examining conditions at the edge of the solar system.
I don’t think they would detect “being scanned” unless they were actively using one of the radar dishes in “recieve” mode. But if it was touched or jostled in any way, NASA sure as heck would notice the change in orientation or speed.
The magnetometer was tri-axial and had a resolution of 0.1nT. There is no chance that any sort of imaginable spacecraft could get close to the probe and not be detected by that thing.
Don’t know. The device was supposed to measure the magnetic field in inter-planetary space as well as near planets, so I am assuming it made at least periodic measurements whilst in cruise. There would be no cost to the probe in leaving it running, but having anything listening is another matter.
Current status of Voyager instruments. The magnetometers on both Voyagers are on. I’m pretty sure all the instruments currently operating have been operating for the whole mission, because they are the ones for measuring the properties of interplanetary space (and now interstellar space).
…although how much of the measurements are transmitted to the Earth is a different matter. They definitely wouldn’t transmit a minute-by-minute measurement. I don’t think the spacecraft is smart enough to notice a sudden increase in measured value and send that data. The instrument may simply be sampled at a sparse frequency (maybe every few days) and recorded, in which case a brief visit by a spacecraft would be missed.
I would actually expect that the spacecraft is programmed to detect and transmit any sudden changes in any of the instruments. But you have a point about the sampling frequency, which is probably pretty low by now to conserve power.
I am just astonished that both spacecraft are still functioning and relaying data after forty years in space. What an accomplishment, the folks at JPL can be proud.