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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

#31

Post by kortex »

jamincan wrote: post #11
bestouff wrote: post #4

It's funny how the excellent job of the French Ariane launcher is nowhere to be seen in this (and others) article.

Shortly after launch there were quite a few articles talking about how well the launch went on the Ariane and how that allowed the mission to be extended to 20 years or so. I'm not sure who it was anymore (possibly Scott Manley on youtube), but apparently ESA had been setting aside the components for the Ariane 5 that tested best to be used for the launch of JWST to lower the risk of failure and that might explain in…

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

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

#32

Post by gameswithgo »

inamberclad wrote: post #13
PinkMilkshake wrote: post #3

I'm a little embarrassed to say this and I don't know exactly what I pictured in my head, but I had no idea these telescopes were so big[1]. I guess I never saw one pictured next to a human. I've only seen pictures of satellites being worked on so I expected something more human sized? It seems so stupid now, especially since earth telescopes are huge. [1] https://svs.gsfc.nasa.gov/vis/a010000/a013500/a013522/JWST_v.…

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.

original plan was smaller, but military had a mission in mind that required it be bigger, so they went bigger to get military buy in. And of course the imagined mission never happened. I wonder how much money would have been saved!

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

#33

Post by arcticfox »

tunap wrote: post #8
bestouff wrote: post #4

It's funny how the excellent job of the French Ariane launcher is nowhere to be seen in this (and others) article.

That is an interesting observation I never considered. If it were a SpaceX rocket, it would have been mentioned once per paragraph, minimum.

If it was a SpaceX rocket, it would be getting ready to fly again. Expendable rockets have been putting up payloads for 60 years at this point, SpaceX has been flying reusable rockets for less than a decade.

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

#34

Post by sandworm101 »

readthenotes1 wrote: post #23
PinkMilkshake wrote: post #3

I'm a little embarrassed to say this and I don't know exactly what I pictured in my head, but I had no idea these telescopes were so big[1]. I guess I never saw one pictured next to a human. I've only seen pictures of satellites being worked on so I expected something more human sized? It seems so stupid now, especially since earth telescopes are huge. [1] https://svs.gsfc.nasa.gov/vis/a010000/a013500/a013522/JWST_v.…

The human is not to scale if that's the Webb telescope.

I think the height is there, but the human seems otherwise out of proportion. He seems to wide, which gives the illusion that he is shorter. And his head is too big, which again makes him look younger/smaller, more cartoonish. I think this is from a stock cartoon character rather than a real person.

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

#35

Post by thret »

ainiriand wrote: post #16
Denvercoder9 wrote: post #15

Earlier quoted context omitted.

> Also it is a good idea to use metric units for science articles. It's not if you're writing for an American audience that's more familar with imperial units.

Then you can use football fields as measurement unit, following that argument. Or bananas.

'Football fields' seem particularly vague as there are half a dozen different sports called football, and each of these have different sized fields.

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

#38

Post by arcticfox »

ragebol wrote: post #20
slim wrote: post #17

Earlier quoted context omitted.

Ariane 5 was cool in 1995

And now too, since it ~doubled the science/dollar output of the telescope by doubling the lifetime. I think that's cool

"doubled" the lower bound on what was surely an extremely conservative estimate meant to avoid a perception of failure if things didn't go perfectly. The Opportunity rover had a "90-day" expected lifetime and lived until 15 years old. It's great that Ariane performed superbly but this "doubling" calculation is pretty silly.

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

#39

Post by panda-giddiness »

pfdietz wrote: post #28
LeonM wrote: post #25

Earlier quoted context omitted.

The JWT is famous for costing over 10b USD to develop. AFAIK it's the most expensive object ever to be launched into space. I don't think universities should (or could) spend that kind of money on research equipment.

If launch costs are 1% or less per mass of the Ariane 5, mass budgets could be greatly increased, and engineering could become easier. I see no reason ultimately why space telescopes should be much different in cost than terrestrial telescopes. Ultimately I see telescopes being maintained and upgraded in space much as terrestrial telescopes are.

The Webb telescope didn't go several times over budget from growing several times heavier. Novel telescope are expensive because they must address unique engineering challenges with unforeseen costs. You can't just grab a sunshade off the shelf – everything's built bespoke.

Of course, the flip side here is that it would be cheaper to build a second Webb telescope. Maybe we could mass produce a hundred more for a tenth the cost, but it's not clear that would be a hundred times better for astronomy.

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

#40

Post by signatoremo »

bestouff wrote: post #4

It's funny how the excellent job of the French Ariane launcher is nowhere to be seen in this (and others) article.

This is one, among others, right after it was announced. Maybe you don’t follow space news as closely as you think you do?

https://arstechnica.com/science/2022/01/all-hail-the-ariane-...

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