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The James Webb Space Telescope has passed the final mission analysis review

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Re: The James Webb Space Telescope has passed the final mission analysis review

#291

Post by deepsun »

NavinF wrote: post #195
deepsun wrote: post #117

Earlier quoted context omitted.

Also, all robotic space repair satellites are very into military tech (even taking pictures of open space is very strictly controlled, because you may inadvertently take a picture of a military satellite). Not event talking about disabling err.. repairing, de-orbiting, spinning etc other satellites. That types of tech is opposed by military, that's actually one of the reason we don't clear dangerous space garbage (es…

> taking pictures of open space is very strictly controlled, because you may inadvertently take a picture of a military satellite Citation needed

I worked in a private space company, that I was told by SatOps folks. I remember they said only US citizens on US territory could process the photos.

Re: The James Webb Space Telescope has passed the final mission analysis review

#292

Post by justshowpost »

Rebelgecko wrote: post #246
justshowpost wrote: post #158

Earlier quoted context omitted.

But that was just like saying what F-35's mission is to fly high in the skies , sorry. This sort of proves my point, no one knows which exactly research JWST will do upon deployment, because original mission goals mainly became obsolete.

>This sort of proves my point, no one knows which exactly research JWST will do upon deployment The research isn't a secret, JWST is already booked solid for like 18 months after it launches. You can see how that time is allocated across various projects here: https://www.stsci.edu/jwst/science-execution/approved-progra...

Yeah, I read that, just not impressed by minor projects with low outcome. It roughly equal to routine PhD-tier experiments done on the accelerator at some provincial lab.

Just look at breakthrough chances from, for example, 5 days trans-neptunian object search or the pointing of instrument at largely unexplored Uranus system for petty 30 hours.

Re: The James Webb Space Telescope has passed the final mission analysis review

#293

Post by Gustomaximus »

thereddaikon wrote: post #281
Gustomaximus wrote: post #275

Earlier quoted context omitted.

Question if anyone knows: ~9.5 years any reason to not push it out of orbit into space and continue to get signals back for years longer as it floats off? Like the voyagers?

JWST isn't a probe like Voyager. It's job isn't to go to other worlds and see what's there. Its a space observatory. It does exactly the same job a telescope on earth would do, just in space. The reason why is to avoid light pollution and the interference from earth's atmosphere. So that fuel isn't used for going places, its for aiming the telescope and keeping it steady. Once the fuel is gone it can no longer contro…

I understand it's not designed for exploration, but my thinking is given the other alternative is burn it up in the atmosphere isn't it better to get a bit longer (few years?) use as it drifts off vs burnt up.

With the you need to aim it, could they sent it to a slow spin/wobble and time image capture as focus would occasionally pass by things of interest? Not sure if it needs to be relatively stable for that long timed exposure.

There is probably good reason for not doing this and trying to understand why.

Re: The James Webb Space Telescope has passed the final mission analysis review

#294

Post by polytely »

eganist wrote: post #148
justshowpost wrote: post #137

Earlier quoted context omitted.

Yes, if you prefer eye candy photos to public safety. By the way will James Webb wield a modern eye candy capable sensor? Not sure about that. There is few worth from remote sensing unreachable (even in theory) objects. Kepler already proved theoretized Goldilocks Zone rocky planets and, in general, provided a lot of data for non-field research (less exciting than Hubble photos indeed). Last, but not least, what's th…

I hate how shortsighted these comments tend to be, but I can understand them. The money for projects like this, largely due to the sensitive nature of it all, still ends up staying local to the governments funding the projects, which means a significant minority of it still gets recouped in taxes two or three degrees down, and the balance that can't be recouped still ends up funding colossal technological advances, e…

Another important point to consider is that by having these big projects you maintain the ability to do them, capabilities need to be maintained by exercising them.

Re: The James Webb Space Telescope has passed the final mission analysis review

#295

Post by seb1204 »

wolverine876 wrote: post #290
vimacs2 wrote: post #282

Earlier quoted context omitted.

Considering that they themselves made the telescope, do you consider all forms of self expression propoganda?

> self expression This isn't art. And yes, I don't trust corporate press releases (though I'm not sure "propaganda" is the right term); do you?

I agree that one needs to be critical or corporate videos. I've watched the video and it is appealing to feelings and has very little technical details.

It impresses by outlining the size and some of the complexity but nothing more. It does not give dates, cost or other numbers. I liked it but would like a much more technical documentation too.

Re: The James Webb Space Telescope has passed the final mission analysis review

#296

Post by thereddaikon »

Gustomaximus wrote: post #293
thereddaikon wrote: post #281

Earlier quoted context omitted.

JWST isn't a probe like Voyager. It's job isn't to go to other worlds and see what's there. Its a space observatory. It does exactly the same job a telescope on earth would do, just in space. The reason why is to avoid light pollution and the interference from earth's atmosphere. So that fuel isn't used for going places, its for aiming the telescope and keeping it steady. Once the fuel is gone it can no longer contro…

I understand it's not designed for exploration, but my thinking is given the other alternative is burn it up in the atmosphere isn't it better to get a bit longer (few years?) use as it drifts off vs burnt up. With the you need to aim it, could they sent it to a slow spin/wobble and time image capture as focus would occasionally pass by things of interest? Not sure if it needs to be relatively stable for that long ti…

Don't worry, JWST isn't going to burn up for a few billion years. Until the Sun expands into a red giant at least.

They are sending it to the L2 lagrange point which is further out that the moon. That's also why they are so careful about making sure the origami sun shield works right the first time. If it screws up the whole mission is lost because there's no chance to fly some astronauts out there to fix it like we did with Hubble.

As for exposures while its spinning, I was under the impression these are really long exposures and require it to be precisely aimed for quite awhile.

Re: The James Webb Space Telescope has passed the final mission analysis review

#297

Post by bumby »

spaetzleesser wrote: post #286
bumby wrote: post #280

Earlier quoted context omitted.

> The upside is automation is making it go smoother and be less burdensome, because simulated testing truly is high enough fidelity I agree to an extent, but there's also a risk of simulation breeding a false sense of security even when simulations are conducted well. The investigation of the CST-100 "anomalous" test flight had 21 findings related to software simulations and testing, some related to lack of fidelity.…

The good thing about simulations is that once you have figured out a problem it won’t make the same mistake again. That’s the strength of computing

I agree, but the problem with this case was that simulations led to complacency about not thinking they needed integration tests. That's much rarely in the hardware domain. It's not really meant to be a critique of simulations but rather how we use them.

Re: The James Webb Space Telescope has passed the final mission analysis review

#298

Post by zabzonk »

thereddaikon wrote: post #296
Gustomaximus wrote: post #293

Earlier quoted context omitted.

I understand it's not designed for exploration, but my thinking is given the other alternative is burn it up in the atmosphere isn't it better to get a bit longer (few years?) use as it drifts off vs burnt up. With the you need to aim it, could they sent it to a slow spin/wobble and time image capture as focus would occasionally pass by things of interest? Not sure if it needs to be relatively stable for that long ti…

Don't worry, JWST isn't going to burn up for a few billion years. Until the Sun expands into a red giant at least. They are sending it to the L2 lagrange point which is further out that the moon. That's also why they are so careful about making sure the origami sun shield works right the first time. If it screws up the whole mission is lost because there's no chance to fly some astronauts out there to fix it like we…

> why they are so careful about making sure the origami sun shield works right

They cannot really test it on Earth, as it must work in free-fall. Given the past problems with unfolding these things, I have a horrible suspicion that it won't work, and we won't be able get to L2 to fix it.

Re: The James Webb Space Telescope has passed the final mission analysis review

#299

Post by shawkinaw »

bane wrote: post #191

It's my personal belief that these massive R&D space telescope programs are nearing their end. Computational approaches among multiple sensors, combined with good 'ol factory mass manufacturing powered by low-cost reusable launch technology allows for the money spent on one-shot programs like this to be spent and allocated in radical different ways. Instead of building one huge short life-span spacecraft, why not lau…

From watching the documentary linked in another comment, a big part of the JWST’s potential is its deep-infrared sensitivity, which in turn requires very cold temperatures and exquisite shielding, and why it will be literally 1 million miles from Earth. I don’t think you can fake that with computation.

Re: The James Webb Space Telescope has passed the final mission analysis review

#300

Post by [deleted] »

minitoar wrote: post #284
vimacs2 wrote: post #283

Earlier quoted context omitted.

I think their point was your joke doesn't make much sense when only a small subsection of the entire telescope was ever replaced.

In my opinion that's part of what makes it funny, and is also a core issue in the Ship of Theseus problem -- who's to say how much it can be changed and is still "the same thing"? Maybe the thing that was replaced was very small but was very important to the identity.

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