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Comment by Stratoscope | Hacker News Reader

So you're troubleshooting a 47 year old spacecraft that is 15 billion miles away.

The round trip time is 45 hours.

That is some kind of latency!

i wonder if the commands include some kind of conditions in them, so you could account for various things at once without a 90h round trip

https://voyager.gsfc.nasa.gov/Library/DeepCommo_Chapter3--14... (start at pdf page 35) might have context [1].

[1] Sourced via https://voyager.gsfc.nasa.gov/Library/VOY_library.html

And “packet” loss!

Maybe Elon Musk could launch a couple of his Starlink satellites into deep space and reduce that latency.

That or apply xkcd #303: https://xkcd.com/303.

You can increase throughput by adding repeaters around the solar system, but latency has a hard limit due to the speed of light.

Also throughput could be increased by changing or updating the modulation and coding schemes. AFAIK Pioneer and Voyger probes were still using PSK and FSK.

Space lasers?

https://www.jpl.nasa.gov/news/nasas-deep-space-optical-comm-...

A cool idea. But will the additional hops reduce latency or increase it?

It depends on whether they're running at a lower data rate due to the low signal power (which leads to low SNR, reducing channel capacity) or if it's just the speed of light delay.

In the former case, a relay could help quite significantly.

In the latter case, it would just add even more delay.

You can alter throughput. You cannot alter delay. You also can only really broadcast at high power from one side.

Deep space RTT is unavoidable.

Throughput impacts delay when you send non-zero packet sizes.

There isn't enough throughput to achieve a negative delay which offsets the actual flight of light time to reach the object. The ratio of throughput delay to actual light delay is so infinitesimal it might as well be zero.

No, the issue is that the throughput is so low with these very small signal strengths that transferring a meaningful amount of data will result in large delays on that side as well. Speed of light isn't the only thing causing measurable latency.

How can adding more steps, more processing time, possibly longer distances if these hops are not in a straight line, cause a decrease in latency?

More hops = more latency. The fastest way is a straight line between origin and destination.

Congratulations, you are one of today's lucky 10,000 to learn about the speed of light being the ultimate limit for travel and communication!

Sorry to say, this limit applies to Elon Musk and his satellites as well.

how would that even work? On the whole spectrum. From the starlink satellite receiving signal to it being remotely justified in economical terms.

The round trip time is due to the speed of light, no amount of money and hardware thrown at the problem, on earth or in space, will improve that.

Maybe with enough money put into research into quantum entanglement, it might one day yield faster than light communication.

It won't, anymore than research into the speed of a spot of light cast onto a surface by a flashlight will result in faster than light communication.

Elon Musk can improve the speed of light?

Of course, if it were not for the woke and the libs not allowing him to.

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