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It's interesting to note that although the Voyager probes are sometimes depicted as small (compared to satellites like the Hubble, where images of it next to sh
by westbywest 16y ago
It's interesting to note that although the Voyager probes are sometimes depicted as small (compared to satellites like the Hubble, where images of it next to shuttle astronauts are common place), they're not. The diameter of the main dish, 3.7m, is nearly twice the height of an average adult, and height of the magnometer boom is comparable to that of a 3-storey house.
Even despite this size, the article mentions the current transmission rate, a measly 1.2kbs, despite what is probably the most ideal antenna size & placement feasible, both on Earth and on the probe. Doesn't this suggest there are pragmatic limits to the operational range of 2-way radio transmission throughout the solar system?
I am curious if future such deep-space science missions would be more effective if they instead launched swarms of micro-probes, where the probes arranged themselves radially around a center-point to effect a very large antenna, possibly up to 1km in diameter.
Also, having so many micro-satellite could allow for a substantial degree of redundancy to tolerate more rad damage, and ideally have less of the mission control acrobatics described in this article. (Which is not to discount the scientists' effort in any way, for it is amazing.)
- InclinedPlane 16y agoVoyager 2 uses X-band radio for communications, more modern systems use Ka-band radio, so with the same size antenna that would increase received power by about a factor of 10. Also, more modern communications technologies such as turbo-codes, which are significantly more efficient than the Reed-Solomon codes used by Voyager 2, further increase throughput for modern systems. Overall though, yes, there are some pretty harsh limits to radio communication across the outer solar system (Voyager 2 is nearly 3 times as far away as Neptune, and well over twice as far away as Pluto's maximum distance from us). But this is fairly easily remedied by switching to yet higher frequencies or using optical communication.
- eru 16y ago> But this is fairly easily remedied by switching to yet higher frequencies or using optical communication. Isn't this the same?
- InclinedPlane 16y agoYes and now. Switching to higher radio frequencies uses a lot of the same systems, switching to optical communication would use entirely different systems (some of which have not even been built yet).
- mturmon 16y agoAntenna size is not the problem with reception. It's white gaussian noise over the deep space channel progressively overcoming signal power as the spacecraft recedes. The channel capacity never drops to zero, but as power drops, data rates get lower and lower.