I still cannot believe NASA managed to re-establish a connection with Voyager 1.
That scene from The Martian where JPL had a hardware copy of Pathfinder on Earth? That’s not apocryphal. NASA keeps a lot of engineering models around for a variety of purposes including this sort of hardware troubleshooting.
It’s a practice they started after Voyager. They shot that patch off into space based off of old documentation, blueprints, and internal memos.
I wont even upgrade the BIOS on my motherboard because im afraid of bricking it.
I think the term “metal” is overused, but this is probably the most metal thing a programmer could possibly do besides join a metal band.
Keep in mind too these guys are writing and reading in like assembly or some precursor to it.
I can only imagine the number of checks and rechecks they probably go through before they press the “send” button. Especially now.
This is nothing like my loosey goosey programming where I just hit compile or download and just wait to see if my change works the way I expect…
Great documentary on the Voyager team: It’s quieter in the twilight
Man I can’t even get my stupid Azure deployment to work and that’s only in Germany.
Interviewer: Tell me an interesting debugging story
Interviewee: …
To me, the physics of the situation makes this all the more impressive.
Voyager has a 23 watt radio. That’s about 10x as much power as a cell phone’s radio, but it’s still small. Voyager is so far away it takes 22.5 hours for the signal to get to earth traveling at light speed. This is a radio beam, not a laser, but it’s extraordinarily tight beam for a radio, with the focus only 0.5 degrees wide, but that means it’s still 1000x wider than the earth when it arrives. It’s being received by some of the biggest antennas ever made, but they’re still only 70m wide, so each one only receives a tiny fraction of the power the power transmitted. So, they’re decoding a signal that’s 10^-18 watts.
So, not only are you debugging a system created half a century ago without being able to see or touch it, you’re doing it with a 2-day delay to see what your changes do, and using the most absurdly powerful radios just to send signals.
The computer side of things is also even more impressive than this makes it sound. A memory chip failed. On Earth, you’d probably try to figure that out by physically looking at the hardware, and then probing it with a multimeter or an oscilloscope or something. They couldn’t do that. They had to debug it by watching the program as it ran and as it tried to use this faulty memory chip and failed in interesting ways. They could interact with it, but only on a 2 day delay. They also had to know that any wrong move and the little control they had over it could fail and it would be fully dead.
So, a malfunctioning computer that you can only interact with at 40 bits per second, that takes 2 full days between every send and receive, that has flaky hardware and was designed more than 50 years ago.
Still faster than the average Windows update.
When I hear what they did, I was blown away. A 50 year old computer (that was probably designed a decade before launching) and the geniuses that built that put in the facility to completely reprogram it a light-day away.
