>"They're very primitive computers compared to what's in your cell phone,"
I do not understand why they can't just swap out the computer for a better and more modern one. Am I missing something here?
NASA can't figure out what's causing computer issues on the Hubble telescope
141–150 of 333 posts
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#142I 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 Very Expensive Mission to the telescope only to find out the CPU was the issue, and if you had figured that out originally you wouldn't be up here with four memory modules.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#143Earlier quoted context omitted.
The Space Shuttle is the only vehicle ever built that can do in-orbit service. It's not that the Hubble is special in that regard, it is that the Shuttle was special.
So does this also mean that the ISS is no longer able to get serviced, or are there projects to work on in-orbit service vehicles?
> So does this also mean that the ISS is no longer able to get serviced, or are there projects to work on in-orbit service vehicles?
AIUI, The ISS can be serviced from the ISS if the appropriate supplies and personnel are sent up, but it doesn't have the delta-V to zip around other orbits servicing other satellites, so it is okay without the the shuttle for itself, but doesn't substitute for it for other things needing orbital service.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#144Maybe the James Webb will go up some day...
When we power our quantum computers with room temperature superconductors and sustainable fusion.
(all 20 years away ofcourse)
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#145>"They're very primitive computers compared to what's in your cell phone," I do not understand why they can't just swap out the computer for a better and more modern one. Am I missing something here?
How do you propose they perform the physical swap?
The space vehicles we used for this purpose have been retired and we have no replacements.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#146"If this computer were in the lab, we'd be hooking up monitors and testing the inputs and outputs all over the place, and would be really quick to diagnose it," he said. "All we can do is send a command from our limited set of commands and then see what data comes out of the computer and then send that data down and try to analyze it."
They've just mostly described my career.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#147Earlier quoted context omitted.
Job Posting: NASA programmer, needs at least 1 wpm typing speed and experience with compiling large projects.
The amount of preparation is much, much more than every other "accessible" installation. Typos are the worst to recover from, backspace usually doesnt exist. As I've sent commands to our Linux-running satellites, its usually prepending your commands with ctrl-c characters and a couple newlines at the end, just to make sure it runs and nothing is left in the buffer. There is also a possibility that commands get execut…
Very fascinating! You haven't happened to written a blog post or something on this, have you? I am sure HN would love reading about it.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#148"If this computer were in the lab, we'd be hooking up monitors and testing the inputs and outputs all over the place, and would be really quick to diagnose it," he said. "All we can do is send a command from our limited set of commands and then see what data comes out of the computer and then send that data down and try to analyze it." They've just mostly described my career.
Still probably faster than deploying to AWS.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#149>"They're very primitive computers compared to what's in your cell phone," I do not understand why they can't just swap out the computer for a better and more modern one. Am I missing something here?
> Am I missing something here?
When dealing with high-latency, high-radiation environments, more modern isn't necessarily better: denser ICs mean greater susceptibility to radiation (and consequently more expensive hardening). They also can't exactly fly up there and swap out random bits on short notice -- I'm not sure if the US even has a the current capability to perform physical maintenance on the Hubble.
Re: NASA can't figure out what's causing computer issues on the Hubble telescope
#150>"They're very primitive computers compared to what's in your cell phone," I do not understand why they can't just swap out the computer for a better and more modern one. Am I missing something here?
It’s in outer space