Earlier quoted context omitted.
This sort of comment is why I still read HN.
And the people downvoting this comment is why I will stop reading HN.
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NASA can't figure out what's causing computer issues on the Hubble telescope
211–220 of 333 posts
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#212pushes 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.
This would be cool for earth satellites. On the other hand watching a stream involving something on Mars, let alone voyager, would be pretty boring! Send: ls Ok let's take a 20 minute break.
I've worked on something like this, just a lot more mundane. We had Linux PCs strapped to the ceiling of various locations, mostly malls, together with a camera and projector to produce an interactive display on the floor. I had a couple of times where somebody would be onsite and the projector would be off or the display would be mangled. And it takes quite a while to get a lift to get up to the box (if it would even be allowed at that time of day), there was no network at that time, and all they had was a wireless IR keyboard that occasionally dropped keypresses.
Imagine dictating shell commands, over the phone, to a salesperson who has no idea what half the characters are that you're asking him to type, and the only output signal I could come up with was ejecting the CD tray, which was just visible from the ground...
(Note that the goal wasn't usually to fix things on the spot, it was more to triage things like whether we needed to have a replacement projector on hand, which was a big deal.)
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#213I 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…
Forth yes, lisp not. Lisp was only used on ground to simulate the rover.
Also a repl in space only makes sense in earth orbit, but not farther away, with 8-20min waiting time for a packet roundtrip to Mars. Those machines really need proper and faster decision making (AI, think lots of `if` statements and proper modeling) on board, eg to perform landing or docking maneuvers. Or to detect and workaround radiation damage in its own circuits.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#214I am no space expert but maybe they forgot to disable Android system updates, that's what seems to have caused my Samsung Tab S2 to slow to a crawl ;-)
Google pushing unwanted apps
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#215I 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. My guess would be that they want to try that method only if this debugging doesn't work. Imagine that there's an electrical issue in item 1 that fries item 2. If you switch over to item 2b, then you fry item 2b too! This is exactly what happened with the Soviet Salyut 7 station. They tripped an over-curre…
> Mission controllers, very tired now that the end of their 24-hour shift was approaching
Are shifts this long still common practice in US or RU space programs?
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#216Earlier quoted context omitted.
Interesting thought. I would say something like the hubble transcends politcal/governmental boundaries... although I do wonder how much if its software is used in other secretive satellites.
Hubble is basically a repurposed spy satellite so it may still be sensitive. Although I doubt any of its sisters are still flying.
On the contrary I doubt that the US military would give up advanced imaging technology, like reading car plates from space, for nothing. That's the Hubble. Nothing else comes close.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#217Earlier quoted context omitted.
Conversation.
It's arguably even worse than just commenting "This." At least that is small enough you can scan over it and barely even register its existence. But this fedora-tipping "Thank you kind sir this is the type of Internet Content I enjoy!" doesn't even afford you that luxury.
How could it have been reworded to avoid the "fedora-tipping" connotation?
I'm being sincere here since I also appreciate book recommendations and I get probably half my book recommendations from HN.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#218Programmer/analyst here and ready to help you NASA, just ask me and I'll clear a few hours of my agenda for you. I know people say this a lot, but in this case I really think a (at least partial) rewrite in Rust of the Hubble software would be very beneficial. We could gather some of the most distinguished coders here in hacker-news and create a task force to show them the benefits of rust's memory safety.
Then maybe lookup "stack overflow" in rust, and you will be delighted. https://github.com/rust-lang/rust/issues?q=is%3Aissue+is%3Ao...
583 closed, 156 open. That much to "memory safety" in rust.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#219I 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…
> 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 effort), I wonder if they have some equivalently interactive system on-board the while your "average" Lisp might be unsuitable for hard real-time applications (due to the presence of a garbage…
As long as there aren't cycles of course you can do deterministic GC, it's just reference counting. It also helps if the program is single-threaded since otherwise any memory allocation/freeing can be unpredictable (since it probably locks.)
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#220Earlier quoted context omitted.
If you want to see debugging a computer in space, check out Apollo 13's sequel, Apollo 14. The moon landing is being held up by shorted-out switch that's causing the LM to abort the landing, and it's up to the programmers back home to figure out how to work around it in time to allow the landing. Apollo 13 was the story of a 'successful failure', while Apollo 14 shows how hard work and creative thinking can turn fail…
Is there actually an Apollo 14 movie? I can find Apollo 18 but not a Apollo 14 feature movie. I saw this but it's a short documentary and may not be what you meant: https://www.amazon.com/Apollo-14-Complete-Downlink-Edition/d...
No, or at least not that I know of. I was having a bit of fun by declaring Apollo 14 (the mission) the sequel to Apollo 13 (the mission).