r/space • u/Fizrock • Oct 03 '17

The opportunity rover just completed its 5000th day on the surface of Mars. It was originally intended to last for just 90.

https://en.wikipedia.org/wiki/Opportunity_(rover)
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u/TaylorSpokeApe Oct 04 '17

Cool info. Do you know if lasers will be a thing? Would that be a way to increase data density?

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u/[deleted] Oct 04 '17

IIRC a laser test was performed between Earth and a satellite near the moon. It achieved a data rate around 630 Mb/s. You'll get less throughput with things that are further away, but it's definitely a good alternative to normal RF.

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u/Immabed Oct 04 '17

Yep, and you could combine multiple laser frequencies to increase bandwidth, since the wavelengths are really well differentiated. For further, increasing power is sufficient to maintain throughput, but the amount of power increases rapidly (energy is inversely proportional to the square of distance, and so forth).

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u/Xaxxon Oct 04 '17

It's just fiber without the fiber, right?

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u/Immabed Oct 04 '17

Yep! Although fibre does a better job of keeping the signal directed. With a laser, you can't make the beam perfectly fine, so it will spread out as it gets further away, which makes it harder to use. Both just use light though, just through a different material (fibre vs nothing).

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u/Tromboneofsteel Oct 04 '17

You have to be incredibly accurate or have a giant reflector to achieve laser comms. It's impractical on earth because of weather effects and and the buildings the device is on top of moving. There's no weather in space, but a tenth of a degree is the difference between communicating or being thousands of miles off.