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Comment by bruce511 | Hacker News Reader

Everything about Voyager is just mind-blowing. These are 45 year old electronic devices, using 70's tech, with zero maintenance, operating 22 light hours away.

At that range they can still send messages detectable on earth. 9 out of 10 instruments are still working. People just leaving school when they launched are already retired.

This is one time when the adage "they don't make them like they used to" is well applied.

Hat tip to all involved.

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Btw, you can see the occasional communication with Voyager at https://eyes.nasa.gov/dsn/dsn.html

As I write this, one of the dishes at Madrid just went to "Setup" for communication with VGR1.

(late edit - some of the stats from the 'more info' at the bottom of the spacecraft panel)

    DATA RATE       160.0 b/sec
    POWER RECEIVED  -160 dBm (1.0 x 10-22 kW)

Agreed, but I believe Voyager is 18.5 light hours away, not 22. The article says it is 20 billion km away which is 18.5 light hours.

However the article also states signals take 22 hours to reach the spacecraft. Do radio waves travel slower than the speed of light even in the vacuum of space? I assume the waves do not spend the extra 3.5 hours in Earth's atmosphere!

The article is rounding up, and the parent comment is talking about Voyager 1.

Specifically: Voyager 1 is 23.8 billion km (23.8 Tm), and Voyager 2 is 18.3 Tm.

For those that might not be aware, Voyager 2 launched before Voyager 1, so the distance discrepancy is not due to the further one being launched first

Voyager 2 was launched first but on a less direct trajectory out of the system which allowed it to visit Uranus and Neptune. Voyager 1 is going much faster

https://voyager.jpl.nasa.gov/mission/status/

There is an effect called dispersion, which causes different frequencies of electromagnetic radiation to travel through a medium at different speeds (lower frequencies => slower).

It's strong enough to be noticeable in the case of pulsars (but probably insignificant inside the solar system).

I think it's because space isn't a perfect vacuum. The interstellar medium is a mix of gas and dust that slow down and weaken the signal. That effect is known as dispersion.

With that said, it seems like the article might be inaccurate. That discrepancy seems too large to be explained by dispersion. I'm not an expert though.

edit: I think the author got Voyager 1's distance mixed up with Voyager 2. Voyager 1 is ~22 (21.6) light hours away.

Sounds more like ChatGPT got it mixed up.

Don't confused TTFB with message transport time. With a low bandwidth link, throughput becomes part of latency. Probably not 3.5 hours, but some fraction of that.

Voyager 2 had 11 instruments. 5 are still active. But still, it is a remarkable piece of technology.

I mean, with a few notable exceptions, NASA's scientific missions have an amazing record of lasting much longer than they were designed for, Hubble and the Mars rovers & helicopter being amazing feats of lasting longer then they should.

> Everything about Voyager is just mind-blowing. These are 45 year old electronic devices, using 70's tech, with zero maintenance, operating 22 light hours away.

No, what is mind blowing is that we are not able to do it again.

We did do it again. We got New Horizons out to Pluto a lot faster, without the aid of the remarkable alignment that made Voyager possible.

We keep exploring the solar system. There's no reason to repeat the same experiments. We've explored the planets in a lot more depth, and just launched even more.

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