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NASA can't figure out what's causing computer issues on the Hubble telescope

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Re: NASA can't figure out what's causing computer issues on the Hubble telescope

#201

Post by macksd »

qzw wrote: post #7

pushes up glasses I would watch the heck out of a Twitch stream of their debugging/brainstorming sessions. I always loved the movie Apollo 13 , especially the technical troubleshooting parts.

Honestly that movie is a lot of why I got into math and engineering.

Jim Lovell was undeniably a badass but I watched that movie and thought the heroes were the ones reading telemetry off a computer screen and using their slide rule to figure out what to do. I hope Hidden Figures does that for another generation.

Re: NASA can't figure out what's causing computer issues on the Hubble telescope

#202

Post by gentleman11 »

NeutronStar wrote: post #176
barkingcat wrote: post #166

Earlier quoted context omitted.

And the people downvoting this comment is why I will stop reading HN.

What did that comment actually bring to the conversation?

Occasionally, very occasionally, it’s nice to read somebody just expressing enthusiasm instead of just posting a clever counter argument. It’s like a spice that you only want a little of but that’s still nice

Re: NASA can't figure out what's causing computer issues on the Hubble telescope

#203

Post by unnouinceput »

Quote: "Most of Hubble's components have redundant back-ups, so once scientists figure out the specific component that's causing the computer problem, they can remotely switch over to its back-up part."

So it's time to do what every gamer does when the rig fails. Switch parts and see who's the culprit. And yes, I do understand the next quote:

But between having nothing anymore, since Hubble had its last maintenance in 2009 (per quote: "The last time astronauts visited Hubble was in 2009 for its fifth and final servicing mission.") and have something now that definitely would fail later, I'd choose the latter.

Re: NASA can't figure out what's causing computer issues on the Hubble telescope

#204

Post by nucleardog »

edgeform wrote: post #142
fouric wrote: post #17

I know that, at different times, NASA has used Forth[1] and Lisp[2] in some of their space applications. Both of these languages offer REPLs that generally accelerate the debugging process, and while your "average" Lisp might be unsuitable for hard real-time applications (due to the presence of a garbage collector, usually without the hard real-time constraints that you can get out of garbage collectors with extreme…

> Wait, then why don't they just switch over each component in turn? The "divide and conquer" debugging strategy. Let's say the CPU is the actual issue, but the problem manifests itself in the memory module. You swap over to the backup memory module, and suddenly the problem vanishes! Two months later, the problem manifests again. Identical presentation. This time, there is no backup to switch over to test. You fly a…

Let's say the memory is the actual issue, but it's manifested itself by data being corrupted and triggering undesired behaviour. Unfortunately, the corrupted state has already been written back to persistent storage.

So you swap in the backup storage module and all your problems go away. Until it happens again and corrupts _that_ too.

Re: NASA can't figure out what's causing computer issues on the Hubble telescope

#205

Post by Izkata »

idreyn wrote: post #104
qzw wrote: post #7

pushes up glasses I would watch the heck out of a Twitch stream of their debugging/brainstorming sessions. I always loved the movie Apollo 13 , especially the technical troubleshooting parts.

In case you haven't seen it: https://apolloinrealtime.org/13/

Fun weirdness of even limited multilingualness: For some reason my brain first parsed this as "a pollo in real time" - or, from Spanish, "a chicken in real time".

Re: NASA can't figure out what's causing computer issues on the Hubble telescope

#206

Post by macintux »

quenix wrote: post #200
macintux wrote: post #192

Earlier quoted context omitted.

Humor that doesn’t contribute to the conversation is generally discouraged.

I'm not sure I understand this. Humor generally doesn't "contribute to a discussion"—it's purely that, humorous. I'm not sure how OP's comment contributes any less than any other joke one could have made.

Really clever humor can entertain and educate, although admittedly it’s rare.

The most common sentiment I see when people attempt cheap jokes is that Reddit is a more appropriate forum.

Re: NASA can't figure out what's causing computer issues on the Hubble telescope

#207

Post by Izkata »

eschneider wrote: post #174
qzw wrote: post #7

pushes up glasses I would watch the heck out of a Twitch stream of their debugging/brainstorming sessions. I always loved the movie Apollo 13 , especially the technical troubleshooting parts.

I dunno. That sort of thing is exactly my job, except the remote devices are still on earth somewheres. What you'd see is me sitting in a library drinking coffee and looking at source code and schematics until I had an answer that matched the evidence. Satisfying, but not exactly must watch tv.

> Satisfying, but not exactly must watch tv.

What's in your head could be though. That's my pet theory on the movie Hackers, what we're seeing on the computer screens isn't what's actually there, it's the characters' mental constructs visualized.

Re: NASA can't figure out what's causing computer issues on the Hubble telescope

#209

Post by wongarsu »

mikeytown2 wrote: post #40
nashashmi wrote: post #5

> Most of Hubble's components have redundant back-ups, so once scientists figure out the specific component that's causing the computer problem, they can remotely switch over to its back-up part. Of course they do! I wonder if they ever had to put another part out of service. I also wonder whether the twin of the part could also suffer the same failure at the same time without being used.

Gyroscopes are in short supply on Hubble currently

And that despite regular servicing back when we still had the Space Shuttle.

Hubble started out with 6 gyroscopes, in 1996 they replaced four of them, by 1999 four had failed so they replaced all six, by 2009 three had failed again, so they replaced all six. Now they are again down to three, and one of the remaining ones has a defect that required some workarounds. The last three gyros are at least a new design that should last a bit longer.

Re: NASA can't figure out what's causing computer issues on the Hubble telescope

#210

Post by CGamesPlay »

londons_explore wrote: post #129
35fbe7d3d5b9 wrote: post #107

Earlier quoted context omitted.

One of the best senior engineers I worked with taught me how to run an outage. The most important thing? Stop what you are doing, take charge, and get everyone else to stop what they are doing. The best case scenario of a bunch of engineers flailing about on a bridge turning knobs is that you luck into a fix but don't know how you got there. But you're more likely to make things worse.

In my experience, the best strategy depends a lot on the severity of the outage. If all the alarms are going off because of a loss of redundancy, then currently there is no outage. The correct move should be carefully considered, and maybe tested in the sandbox environment. If there is currently a 100% outage, it's best to go all out on trying every possible fix, because typically you'll restore service quicker that…

> If there is currently a 100% outage, it's best to go all out on trying every possible fix, because typically you'll restore service quicker that way. Sure, occasionally you dig yourself a deeper hole, but usually it's the best strategy.

Almost assuredly not. If a system hits a 100% outage, there are about to be a series of cascading failures by dependent systems. If you don't even understand which system is the root cause, all you're doing is testing a bunch of never-before-tried combinations in production and hoping something works.

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