It's amazing how much redundancy was built into those out-of-touch systems, 30 years ago.
However, the number of backup units is finite, so let's hope the now-operating system can last for several more decades.
The part that caught my eye was redundancy on memory.
>> Hubble’s operators initially thought a memory module was at fault but switching to one of three backup modules produced the same error.
Apparently Hubble has 4 memory modules which are switchable! I'd love to see how that works. Actually, I'd be fascinated to get a walkthrough of the overall architecture. It might give insights for how we keep business continuity by first accepting that hardware and software will fail.
Classic movie scenario. Hubble's down, and we need it now. No-one can solve the errors. Old guy walks in, worked on Hubble 30 years ago.
"There's a backup module, with an override command to activate it, but it won't work with the system down. You'll have to use the manual override switch - on the telescope."
…or as I try to occasionally discuss here… let’s simply develop the unmanned robotic capability to service Hubble, etc
I found one discussion from 7 years ago
“… I think we should start a more extensive national unmanned space program. For example, if the Hubble, or its replacement, needs to be fixed, we should have an unmanned answer, for instance.”
Huble was never meant for this, if you look at all the systems present on ISS for automated docking, none of that is on Hubble. Access to modules inside Hubble was never meant for robots with very limited dexterity either. Being able to do something like that would be a huge feat of engineering in my opinion (and extremely expensive).
I am fairly certain it would be faster and cheaper to just build a new one from scratch.
And even if you managed to make a robot to service Hubble, it then would only be able to service Hubble and nothing else. JWT for example is completely different.
On the long term you are right that this is a capability we need, but this needs to be taken into consideration while building the telescope/satellite/whatever: automated docking mechanism, standard ports and dimension of parts etc. etc.
I'm pretty sure the pitch here is "a robotic being with human perception, dexterity, and manipulation, but who doesn't breathe air and never gets tired."
So the idea is that you don't need to specialize it to the thing it's meant to work on, because it works on whatever a human works on. A similar idea drove a lot of the DARPA Robotics challenge, with its emphasis on being able to drive a normalish vehicle, open a door, climb a ladder, use a regular power tool, etc.
Anyway, I think the state of the art for all this is still pretty far away, which is why the instinct is to assume we're talking about something specialized.
> I think the state of the art for all this is still pretty far away, which is why the instinct is to assume we're talking about something specialized.
Yes, that's exactly what I thought. If we are talking about AGI + human level robotic dexterity, then the use of "simply" becomes even funnier.
> Access to modules inside Hubble was never meant for robots with very limited dexterity either.
It was also never meant for humans with less limited dexterity.
I recall one of the Hubble servicing missions I watched on NASA TV, in which they had to bolt a special adapter plate over a cover, unscrew over a hundred tiny non-captive screws (which the adapter plate was designed to catch, so they wouldn't float away), and only then could they open that cover. That part of the telescope clearly wasn't designed to be serviced in space.
To be fair, they wasn't expecting Hubble to last beyond the end of the service date. I recalled it was ~10~ 15 years? They have no way of knowing this beforehand.
Edit:saw the comment somewhere that it is 15 years.
I think 'simply' is precisely the wrong adjective.
Plus you'd still need spare parts. Why would I build a robot to swap parts, when I can simply put all of the spare parts into the telescope and swap over to them electronically?
The other thing to remember was that Hubble was designed in an era that the Space Shuttle was meant to make manned missions to repair / upgrade commonplace. My understanding is that this was actually done at least once to Hubble (maybe more? I forget); but unfortunately for Reasons, NASA turned out to be incapable of resisting cutting corners which put people's lives at risk (Challenger, Colombia). A system designed today would be designed assuming that it would be robots or nothing.
I was curious myself, and it turns out there were five missions, starting with the one to compensate for the incorrectly ground mirror. IIRC the final one was in doubt, as there was no possibility of a rescue mission in the event of irreparable damage on launch.
The final servicing mission (STS-125) ended up with a contingency plan for damage on launch, STS-400. Another shuttle was prepped and on the pad for a rescue mission if the primary shuttle was damaged.
But in reality, the ideal system is probably a combination of built-in redundancy / spares for parts that can work that way; and then robots for the kinds of things that are too complicated to have a built-in failover.
Or we could build a cheaper telescope that is less redundant more quickly, and launch a new one every 5 years. Launch prices are falling, so this could be more economical than building expensive long-lasting telescopes.
There's several problems with that approach. The first is there's going to be a minimum size for a telescope to be useful as a scientific instrument. For a telescope intending to be in any way a contender for Hubble's mission it would need a primary mirror a meter or more in diameter. Then it needs reaction wheels for precision aiming, RCS, instruments, electronics, and power.
At a minimum you're outside of "smallsat" size range. Even building a lot of them the precision manufacturing of the optics and steering systems require a lot of ground based testing, calibration, and qualification. Between the size and precision even your "cheap" Hubble's aren't all that cheap.
The second problem is terrestrial telescopes have gotten really good and are far cheaper for any given mirror size. Their instrumentation doesn't have nearly the same mass restrictions and can be swapped out routinely.
Space telescopes make sense when their mission requires them to be space based like observing wavelengths that don't reach the surface of Earth.
While we don't have a direct capability to do this now, some of the large programs of record are being built so that robotic servicing may be possible.
JWST has a docking port for a future robotic servicing mission.
Nancy Grace Roman (formerly WFIRST) space telescope has grappling points on the spacecraft for robotic servicing.
starship wouldn't really fit the mission profile of sending 2-3 astronauts to hubble orbit for EVA. The same starship could instead deliver a fleet of replica hubbles to lagrange points autonomously.
I agree in a more general sense: space is a natural domain for robots, not humans, and we should be designing out space flight capability with that in mind. We have some almost 50 year old robots advising us on the heliopause right now.
The general problem of repairing Hubble robotically is unlikely to be solvable within the lifetime of the telescope, but future devices could be designed with that in mind.
NASA doesn't know how to do anything cheaply. They have two space telescopes sitting in a warehouse since 2011 that were donated by the NRO. They're estimating $4 billion to launch and run just one of them, more than a decade after the donation. And you know it'll cost double the estimate and take an extra 5 years.
Why dont they just give others to do their work? Last I remember india sent a probe to Mars for less than amount it took for making the movie Mars featuring Matt Damon ?
agreed but what job creation is a project sitting dead for 5 years? are they giving people salary for not doing anything and then claiming too much costs or something else?
Just to clarify: Hubble was not an NRO donation, although it bears some similarity to the KH-11, an NRO satellite from the 70s. It is not confirmed whether the two actually share parts, as the KH-11 is still classified.
The NRO did donate two unlaunched telescopes to NASA in 2012 (with optics present but sans electronics), which still have not yet been retrofitted and launched.
>> Hubble’s operators initially thought a memory module was at fault but switching to one of three backup modules produced the same error.
Apparently Hubble has 4 memory modules which are switchable! I'd love to see how that works. Actually, I'd be fascinated to get a walkthrough of the overall architecture. It might give insights for how we keep business continuity by first accepting that hardware and software will fail.