Hubble telescope has new lease on life after computer swap appears to fix glitch

My same grandpa that worked on the Hubble mirror also worked on anti-ICBM lasers back in the 70s. Apparently these devices had a tendency to melt their own mirrors, and that led to the development on self-deforming mirrors to deflect heat from hotspots.

(He also worked on the TEAL AMBER and TEAL BLUE satellite surveillance systems, and probably others that he never even talked about.)

> It still amazes me that one, the mirrors are sensitive enough to the deformation of Earth's gravity to have an effect and two, that we are now very good at compensating for this now.

I make telescope mirrors.

This problem was well understood since the time of Herschel. We just have better solutions now.

The fact that this is a space scope is irrelevant to the fact that gravity will cause issues. For any telescope, you have to account for differences in the way the mirror is deformed in manufacturing vs in actual usage, and the ways the deformation will change in usage as the scope is leaning at different angles. That is always a thing.

What is particular to the Hubble is that the load in usage is zero (which is unusual), so you have to think about it that way in manufacture. But deformations in manufacture are always an issue you have to account for somehow.

Look at it this way: there is an ideal shape that the mirror needs to have, usually a revolution surface of some conic section (parabola, hyperbola, ellipse, circle). The performance of the mirror will track the difference between the ideal surface and the actual mirror. The error allowance depends on the wavelength λ of the observed radiation.

Telescopes where the error is greater than λ/4 just suck, and are unusable. Good performance begins around λ/8. A great mirror may do better than λ/20.

For visible light, λ/4 is 100 nm, or 0.1 microns. That's 10 thousand times less than 1 mm. On that scale, the mirror is made of jelly. If you put it on a rough surface, it will deform. If you put your thumb on it, hold it for a minute so it heats up from your skin, then pull away, there will be a "mountain" left behind on the mirror, under your thumb, until it cools off again.

In many cases, the support structures for large mirrors are complex mechanisms that ensure the force is uniformly distributed across a large number of points on the back of the mirror. Even amateur telescopes built using the Dobsonian template use passive self-balancing support with 3, 6, 9, 18, or even more points, depending on the size / thickness ratio.

To be fair, Kodak made a sister mirror that wasn't chosen to go up, and when the issue on Hubble was found out, Kodak's mirror was found to be perfect.

That's a really positive way to frame it. Thanks for the perspective.

From what I recall the mirror was built to spec, it was the spec that was wrong not the mirror. Do I have that backwards?

The hardware dudes have it harder than software dudes. It’s easy to fix software. Hardware, not so much.

I guess the worst thing you can fuck up in space fairing software is the boot loader. Mess that up and you can’t update the software.

Note: I have never designed software for space. I have no clue what I’m talking about.

I mean, it really was a hardware problem. However, the software guys were not pointing any fingers.

They all really, really believe in the mission. Many are well into their 60s and are waiting for JWST to launch to finally retire. It was supposed to launch YEARS ago, so they are (as a group) getting antsy.

The project I worked one was migrating data from their in house ticket tracking system to Jira. I was importing tickets from 1985 into Jira which obviously didn't exist at that time.

Government job. Low pay. Much stability.

They're probably at a "local optimum" (maybe even global) in their careers. Peak salary, peak expertise match, etc.

Though probably a "different world". It would be hard to retrain to do react development, for example.

They are all considered to be in academia I think so you can put them in that bucket. My impression they all did OK in the compensation department however I'm sure they all could make much more in the private sector. EVERYONE I worked with on that project was a high performing / expert level.

I'm going to guess, no.

Software vendors like Oracle and SAP do everything in their power to lock you into their services while doing the absolute minimum to fulfill any contract.

It took our IT over 4 years to migrate away from Siebel to Salesforce and it's going on 3 years since. I just learned the other day we still have a Siebel DB lingering around as a dirty little secret.

We move away from Lotus Notes over 10 years ago and we still have some Notes Apps used by our Legal Department.

>You can pick another commercial software vendor.

With what's left of your budget, which is now very, very negative. Better to redefine abject failure as success to minimize the chances of it ending your career if you're involved in firm purchasing in any way. It's not like boards of directors have a clue. The big consulting firms will assist pulling the wool and priming the press so they can move onto the next mark. It's impossible to by cynical enough.

It's getting more common than not that they all remove the same popular features and add the same dark patterns.

The couch example ins't just hypothetical.

My dad was on an Air Force Base when the base commander delegated to his wife picking out all the furniture for the base housing. Naturally, every serviceman's wife hated it.

you'd be surprised. At a former job (in IT in academia)...

me: I think we can build something in-house here better than what the vendor will provide, I think the vendor's solution is likely to be a failure for us.

them: Yeah, but if do it in-house and it fails, it's our fault. If the vendor's solution fails, it's their fault -- plenty of very prestigious universities are using this vendor, nobody's going to blame us for choosing them. [Ie, "nobody got fired for picking IBM" basically].

It's not the first space-based observatory, but it's still a _wholly novel_ device, containing instrumentation designed by scientists and engineers in concert to leverage every piece of bleeding edge technology available at the time, and some throughout the process. Everyone of the flagship observatories is moon shot. It's not a mass-produced helicopter or missile. This project in particular is easily one of the wildest feats of science and engineering _ever_ just like Hubble, Cern, and LIGO.

Regarding the bomb, we were trying to end a global conflict, so the comparison couldn't be further off base.

The first atomic bomb was nowhere near as precisely-built as the James Webb telescope has to be.

It is a completely novel design for a space telescope though. On top of that there's no capability [0] to go patch up a sloppy job like we did with Hubble.

[0] Currently at least. Starship could I guess but it was planned way ahead of Starship even being a glimmer in Musk's eye. Do they have any grapple points on it as insurance? I would at this point, just put one of the posts they use on the ISS for Canada Arm to grapple.

It took 25 years to replace the SF Bay Bridge, a much less complex endeavor.

It’s simply how things are done around here these days.

Not to my knowledge. Actually, it was said that lack of smaller space projects was catalyst for creation of Starlink. They expected tons of launches once launch prices dropped but it never materialized so they decided to become their own biggest client.

Who’s theory?

JWST costs upwards to 9 billion USD. An Ariane 5 launch maybe 200 million.

Just because the launch is cheaper doesn’t make the rest of the project less complicated and costly.

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.

> 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.

<pedantic> adverb </pedantic>

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.

Knowing what will go wrong is hard to predict. Having the capacity to have robots service satellites, etc would be extremely useful.

Also, the vision is that robots can build on Mars, for example.

“Simply” means fund the research. My comment was from 7 years ago.

We also need the robots here on earth for dangerous tasks

We’d make impressive progress over each decade with more effort.

> 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?

What if the system that swaps parts fails?

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.

Yes, it really matters. It might not matter from the perspective of just making cool looking images, because you can do that in any wavelength. But for science, the wavelengths matter a lot, and you can learn different things at different wavelengths.