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Voyager 1 runs on 69 KB of memory and an 8-track tape recorder

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Re: Voyager 1 runs on 69 KB of memory and an 8-track tape recorder

#141

Post by basilikum »

tombert wrote: post #125
basilikum wrote: post #108

Earlier quoted context omitted.

curl https://news.ycombinator.com/item?id=47564421#47564679 | wc -c 143927 curl https://news.ycombinator.com/item?id=47564421#47564679 | pup -p --charset utf8 'text{}' | wc -c 30954

Huh, fair enough. I was looking at the network console in the browser and it said 89KB. Almost certainly my fault...sorry!

Our comments don't really contradict each other. The page size without any linked documents like an external style sheet grew to 140KB after your comment. But just the text is 30KB.

Re: Voyager 1 runs on 69 KB of memory and an 8-track tape recorder

#142

Post by bragr »

anovikov wrote: post #133
wongarsu wrote: post #81

Earlier quoted context omitted.

Take decades to catch up to the location of either voyager probe. The probes have be traveling for a long time. They have also taken advantage of a rare planetary alignment that allowed them to visit a lot of planets and get gravity assists from them (converting a tiny portion of the planet's angular momentum into orbital speed for the spacecraft)

Won't ion engines power by something like Kilopower reactor let us do better?

Bunch of napkin math: you'd need something like 10 kilowatts and 140 km/s detla-v to catch up to Voyager in a decade, assuming a New Horizons equivalent Earth escape velocity. The amount of xenon is technically possible, however even assuming impressive 8000 Isp thrusters, your fuel mass fraction ends up being 90+% fuel which doesn't leave a lot of mass for that reactor and radiators.

A 20 year intercept would be pretty reasonable though. It needs about 15 km/s delta v after that NH style escape, about a kilowatt of power, and maybe a 25% fuel mass fraction at 6000 Isp. That's all very reasonable by current standards.

Re: Voyager 1 runs on 69 KB of memory and an 8-track tape recorder

#144

Post by zerd »

saadn92 wrote: post #6

The thruster fix is the part that gets me. They sent a command that would either revive thrusters dead since 2004 or cause a catastrophic explosion, then waited 46 hours for the round trip with zero ability to intervene. That's a production deployment with no rollback, no monitoring dashboard, and a 23-hour latency on your logs. They nailed it.

Based on the communication fix, they also didn't have a simulator, or tests, or complete source code, on a custom instruction set that wasn't well documented, so they had to reverse engineer how it worked. https://www.youtube.com/watch?v=YcUycQoz0zg&t=2366s

Re: Voyager 1 runs on 69 KB of memory and an 8-track tape recorder

#146

Post by toomuchtodo »

joe_mamba wrote: post #102
zitterbewegung wrote: post #74

Earlier quoted context omitted.

A large amount of Voyager 1 & 2 's success isn't just technological it is the ability to take advantage of a specific planetary alignment for a gravity assist [1] that can only occur every 175 years [2] . [1] https://en.wikipedia.org/wiki/Gravity_assist [2] https://en.wikipedia.org/wiki/Voyager_1#/media/File:Voyager_...

Fingers crossed, if we manage not to blow each other up until then, we have 126 years to go till we can try again.

You might enjoy "A Canticle for Leibowitz" on this topic.

https://en.wikipedia.org/wiki/A_Canticle_for_Leibowitz | https://openlibrary.org/works/OL2626638W/A_Canticle_for_Leib...

Re: Voyager 1 runs on 69 KB of memory and an 8-track tape recorder

#147

Post by JKCalhoun »

joezydeco wrote: post #105
pkorzeniewski wrote: post #49

Voyager 1 & 2 is one of my favourite human science achievements, not even so much from technology standpoint, as it's relatively simple compared to what we have now (although that's one of the charms), but just the fact that it's so far away, it still more or less works long after the scheduled mission end time, we can communicate with it and despite all the modern technology progress, it would take decades to catch…

Don't forget that the mission planners figured out the "Grand Tour", calculating orbits and trajectories to slingshot around the Solar System. All with 1960s technology. https://en.wikipedia.org/wiki/Grand_Tour_program

And scrambled to get two machines ready for the small window we had to take advantage of it.

Re: Voyager 1 runs on 69 KB of memory and an 8-track tape recorder

#149

Post by gdubs »

mek6800d2 wrote: post #136
gdubs wrote: post #86

One of my favorite stories about the Voyager mission was how they wanted to grab photos of the outer planets but the click of the tape drive was enough to ruin the long exposures. I made a YouTube short about it a while back: https://youtube.com/shorts/fssIy-wQisA?si=_HM1fgZKGFfaxWhc

I enjoyed your video and it is well done. Unfortunately, I don't think it's true. The Voyager tape drives were similar (if not largely identical) to the earlier Viking Orbiters' DTRs. The Voyager engineers were certainly familiar pre-launch with the motions imparted to the spacecraft by the mechanical movements of the tape drive. The Voyager DTRs were specifically mounted to minimize the effects on the roll axis. Pot…

Thanks! My primary source for this was Carl Sagan's book "A Pale Blue Dot" IIRC — don't have the folder in front of me to double check, but fairly certain.

Edit: found it!

Here's the excerpt. According to Sagan they sent these instructions up. Given his details on what had to be done to boost the signal upload, it sounds like this really did happen:

"...while taking a photograph of a street scene from a moving car. This may sound easy, but it's not: You have to neutralize the most innocent of motions. At zero gravity, the mere start and stop of the on-board tape recorder can jiggle the spacecraft enough to smear the picture.

This problem was solved by sending up commands to the spacecraft's little rocket engines (called thrusters), machines of exquisite sensitivity. With a little puff of gas at the start and stop of each data-taking sequence, the thrusters compensated for the tape-recorder jiggle by turning the entire spacecraft just a little.

To deal with the low radio power received at Earth, the engineers devised a new and more efficient way to record and transmit the data, and the radio telescopes on Earth were electronically linked together with others to increase their sensitivity. Overall, the imaging system worked, by many criteria, better at Uranus..."

Re: Voyager 1 runs on 69 KB of memory and an 8-track tape recorder

#150

Post by pja »

jgalt212 wrote: post #140
pkorzeniewski wrote: post #49

Voyager 1 & 2 is one of my favourite human science achievements, not even so much from technology standpoint, as it's relatively simple compared to what we have now (although that's one of the charms), but just the fact that it's so far away, it still more or less works long after the scheduled mission end time, we can communicate with it and despite all the modern technology progress, it would take decades to catch…

Voyager, Apollo, and Hubble. Everything else NASA has done is a distant 4th place. And it's not like 4th place is trash, it's just that the big 3 are just so impressive.

James Webb Telescope is up there with Hubble.
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