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James Webb telescope reaches its final destination in space, million miles away

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Re: James Webb telescope reaches its final destination in space, million miles away

#321

Post by manquer »

wslack wrote: post #312
dboshardy wrote: post #150

Earlier quoted context omitted.

> the US Navy even let him on a multi-day tour of a nuclear submarine and tape classified information (later redacted) They _paid_ him to tour it. It was a marketing event for the US Navy to drive recruitment.

They neither paid him nor had edit approval on his content besides redacting classified information.

He was covering sciene topics nothing controversial or political if i remember correctly it was about air circulation systems and the fail safes etc.

Beyond classified stuff , there is not much need for edit approval.

Re: James Webb telescope reaches its final destination in space, million miles away

#322

Post by manquer »

PetitPrince wrote: post #126
kortex wrote: post #31

Earlier quoted context omitted.

So they essentially binned the rocket parts much the same way a chip fab would?

They selected the parts that were the most up to spec (not necessarily the strongest, but the most faithful to spec).

Chip binning or most complex systems QC also works that way ?

If it doesn't behave as within parameters defined would the core/chip is binned.

Complex systems can break in unexpected ways if any one parameter is outside range even if it actually better (say more clock speed) , you want to stick to spec.

Re: James Webb telescope reaches its final destination in space, million miles away

#323

Post by TaylorAlexander »

wolverine876 wrote: post #316
TaylorAlexander wrote: post #293

Earlier quoted context omitted.

Mostly I’ve just stopped using gendered terms. In a business letter even if the person is not trans you can’t assume Mr/Mrs/Ms unless you know. If their name is gender neutral or ambiguous I would say “Dear First Last,” though that’s even US/western-centric as not all cultures do it that way. If it’s a really important business letter you should probably find out the persons gender using some other channel. Also if t…

I think we can't avoid these issues and need to come up with solutions. I've never seen Mx, so I think many people would wonder what it meant. Just "M." seems better and matches other usage (though outside contemporary English).

Sure. I would imagine there has been a lot of discussion around this in certain circles. Probably no shortage of good ideas. I think culturally we need to get to the point where most people accept gender as self identified, and the rest will shake out over time.

Re: James Webb telescope reaches its final destination in space, million miles away

#324

Post by manquer »

nexuist wrote: post #109
Dave3of5 wrote: post #98

Earlier quoted context omitted.

Actually Hubble was put into space by a (mostly) reusable system the space shuttle STS-31. That was about 30 years ago.

Calling the Space Shuttle "mostly reusable" is laughable. It cost 1.5 billion dollars per launch [1] whereas a reused Falcon 9 costs 50 million to launch. [1] https://en.wikipedia.org/wiki/Criticism_of_the_Space_Shuttle... [2] https://en.wikipedia.org/wiki/Falcon_9

Reusable does not mean cheap . Usually you want reusable to make it cheaper but not always.

For example your standard AA/AAA batteries are much cheaper if they are one time use than reusable [1]

Reuse may be desirable in a product for environmental impact, turn around time, security or many other concerns.

Shuttle was mostly reusable even the booster components , not cheaply but reusable nonetheless.

[1] it is a crude example, overall cost being more expensive, TCO per cycle will be cheaper for rechargable batteries

Re: James Webb telescope reaches its final destination in space, million miles away

#325

Post by whatshisface »

beerandt wrote: post #311
whatshisface wrote: post #153

Earlier quoted context omitted.

If the military-funded project creates $1M worth of value using $1B of funds, the unfunded project is objectively better.

That's what army mapping service essentially did with early radar distance measuring projects. Huge expensive fleet of 18-wheeler trucks failure. And classical surveying methods beat it in every way at the time. But it was the direct predecessor to microwave communications. It was just portable military distance measuring equipment (like the model-99 dme w/ ~1cm @50km) that used a signal they found easy to piggyback…

It's difficult to say without access to the counterfactual world where GPS was invented based on civilian microwave communication which itself would have evolved from civilian radio communication. We live in a world where the DoD redistributes money away from private industry and towards another sector of private industry, and it is hard to say what would happen if R&D tax laws were changed to move that money back from private military industry R&D to industry-industry R&D.

Re: James Webb telescope reaches its final destination in space, million miles away

#326

Post by manquer »

avmich wrote: post #305
jedberg wrote: post #182

Earlier quoted context omitted.

The shuttle could cary 29,000kg to orbit, the Falcon 9 can only carry 22,000kg (30% more capacity) plus 8 astronauts (Falcon can only carry 3), and was designed and built in the 70s. So yeah the Falcon is an improvement and I'm sure will be better one day, but the Space Shuttle was a huge achievement for its time, and as of today there is no lift system that can match it for both capacity and reusability.

> the Space Shuttle was a huge achievement for its time Agree. > as of today there is no lift system that can match it for both capacity and reusability Disagree. Falcon Heavy lifts higher payloads - you don't count the orbiter mass itself, do you, just like you don't count the mass of the last stage which actually gets to LEO, right? Reusability was also lacking. SSME was made by Rocketdyne, not Pratt and Whitney, w…

It wasn't rapidly or cheaply reusable, but it was reusable yes ?

Re: James Webb telescope reaches its final destination in space, million miles away

#327

Post by c0npr »

zargon wrote: post #302
Buttons840 wrote: post #297

Earlier quoted context omitted.

> But back to military- it's not a coincidence that Hubble fit so perfectly in the shuttle cargo bay. I assume Hubble was built that size because it would fit? No coincidence indeed. And what does that have to do with the military?

> what does that have to do with the military? Hubble is a military spy satelite design.

Not exactly, I think they just use a specific mirror design (2.4m dia.) because they are already manufacturing them to be used in spy satellites.

Re: James Webb telescope reaches its final destination in space, million miles away

#328

Post by robotresearcher »

_yoqn wrote: post #203
inamberclad wrote: post #13

Earlier quoted context omitted.

The space shuttle blows my mind every time I see one. It's huge - the size of an airliner - and would glide back at Mach 25. It's a humbling level of accomplishment.

You can actually go see Endeavor in real life at the L.A. Science Center. Admission is like $2. Regardless of the size, the spectacle is breathtaking.

https://californiasciencecenter.org/exhibits/endeavour-exper...

You can get really close to it, in the current temporary building. Wonderful. You can almost touch it, and you can smell it, and see the scuff and scorch marks. Go before they raise the money for a bigger building and stand it up.

Both Endeavor and Vasa[0] are super, super cool.

[0] https://i.redd.it/7zzqeyu5zyo71.jpg

Re: James Webb telescope reaches its final destination in space, million miles away

#329

Post by SixDouble5321 »

ctdonath wrote: post #63

Amazing how a few meters of mirror can make out objects billions of light-years distant. Yes it's big - insofar as human-built telescopes have been - yet is so relatively minuscule per what it observes. Having gone from first flight to JWST in such a short time is staggering (Wright Bros 120 years ago - I've been alive nearly half that time); how soon will we achieve orders-of-magnitude bigger telescopes? say, multip…

The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars.

-Carl Sagan

Re: James Webb telescope reaches its final destination in space, million miles away

#330

Post by jacquesm »

ridgeguy wrote: post #283
dimator wrote: post #248

Earlier quoted context omitted.

I can't fathom how they have a servo, a linear actuator, or anything else, that can apply pressure to the mirror and keep it there, for years , in the most extreme environments. Every component of this thing is mind bending.

Here's a good paper on the mirror actuators [1]. Skimming, they look like hexapod rotary stepper architecture that would not need power to hold a position, only to change position. [1] https://www.esmats.eu/amspapers/pastpapers/pdfs/2006/warden....

Steppers make good sense for that application, what a beautiful design. 7 nm step size with a repeat accuracy of 1 nm is insane precision.
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