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Shining a Light on Interplanetary Communication
An anonymous reader writes "Researchers at the MIT have developed a new device that they claim could one day boost interplanetary communication to broadband speeds. From the article: 'The new light detector improves detection efficiency to 57 percent at a wavelength of 1,550 nanometers--the same wavelength used by optical fibers on Earth to carry broadband signals to homes and offices. Currently, light detectors only absorb about 20 percent of the light they receive. "It can take hours with the existing wireless radio frequency technology to get useful scientific information back from Mars to Earth," said study team member Karl Berggren from the Massachusetts Institute of Technology. "But an optical link can do that thousands of times faster."'"
Latency isn't going to be fixed, as the speed of light is a constant. The problem, really, is the rate of transfer. If it does take 538 seconds for light to get from mars to earth, there is no reason that this should do anything other then add a 1076 second delay from the first request to the start of data flow... after that there is no reason an un-interupted flow of data shouldn't flow. There is no reason that we shouldn't fix it so that after the delay the data coming in is more dense, with more arriving each second. After all, latency is only important in two way communication, and we shouldn't need to send more then a request for data that needs a responce. Sure, we have to send commands on what to do next, but the robot shouldn't need to respond more then a confirmation. Even if we did need a real dialog, there really isn't anything we can concieve doing at this point that would fix the time it takes to send one message, but we can change how many messeges can be sent at once.
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If optical interplanetary communication is not only possible, but actually more efficient than radio wave communication, what does that mean for the SETI project which analyses radio waves? Shouldn't we expect extraterrestrical civilisations to switch to optical as soon as possible? Did we perhaps look at the wrong frequency all the time?
The Tao of math: The numbers you can count are not the real numbers.
This problem could be solved with "interplanetary routers" which just route the signal around the sun (i.e. there's some relay station e.g. at the same orbit around sun as Mars, but at a large enough distance so that if the line of sight to mars is blocked, the line of sight to that station isn't; whenever Mars is behind the sun, the signal is relayed through that station; this gives an additional latency during that time, but probably better than waiting for the end of the block).
The Tao of math: The numbers you can count are not the real numbers.
Most interplanetary vehicles are absolutely tiny. They are also lightweight. Increasing the diameter of the receiver and adding mirrors and lenses would drastically increase the mass of the craft, let alone the size. Doing that when a solution like this is available would be an almost criminal waste of space/weight on the spacecraft.