4 ms·
How does Voyager know where Earth is, such that it can position the dish correctly? Does it use inertia to keep track? Also, at such an enormous distance, I’d
by manmal 9y ago
How does Voyager know where Earth is, such that it can position the dish correctly? Does it use inertia to keep track?
Also, at such an enormous distance, I’d expect very minor dish positioning errors to result in the loss of the line. It’s awesome that they had the skills to build something like that in the 80s.
- UseStrict 9y agoEven more impressive, Voyageur 1 was launched in September of 1977 [1]. It was originally built on early 1970's technology. An incredible amount of foresight and luck. [1] https://voyager.jpl.nasa.gov/ https://voyager.jpl.nasa.gov/
- cr0sh 9y agoVoyager 1 was launched on September 5, 1977 (notably after Voyager 2 was launched!). The idea for it (a "grand tour" of the planets due to a particular orbital alignment that made such a thing ideal) was hatched in the 1960s...
- jacquesm 9y agoIt doesn't need to point its dish at Earth, it can simply aim for the Sun. It is so far away they are as good as in the same position relative to itself. And the Sun conveniently lights up making aiming a lot easier.
- manmal 9y agoDid they have digital light detectors in the 70s? I mean, it’s trivial now to aim something at the sun now, but they didn’t have image recognition then. A primitive heat sensor perhaps?
- jacquesm 9y agoYes, CDS cells are much older than that, and Ge diodes are light sensitive too.
- Dylan16807 9y agoLooking up the math on that, the high gain antenna is within 3dB of max at up to .3 degrees off-target. It's 132 AU out, so Earth is within .41 degrees of the sun. Good enough!