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James Webb is fully deployed

nasa.gov

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Re: James Webb is fully deployed

#351

Post by jon_richards »

freeflight wrote: post #346
bichiliad wrote: post #250

Earlier quoted context omitted.

One thing they mentioned that kinda sends it home to me is that the telescope is aimed at the dark and away from the sun, and the other side is especially reflective[0]. In other words, one side is too dark to see, and the other is too bright to see. [0]: https://twitter.com/NASAWebb/status/1479161991252131841

> the telescope is aimed at the dark and away from the sun To be more specific; It's "parked" in an orbit [0] that constantly puts Earth between the sun and James Webb. So it's not only aimed away from the sun, Earth is also acting as a planetary scale sunscreen for it. [0] https://en.wikipedia.org/wiki/Lagrange_point

It’s orbiting around L2. I’m not sure if it’s actually in the shadow of earth. Keep in mind that it’s still powered by a solar array.

Re: James Webb is fully deployed

#352

Post by bsder »

davesque wrote: post #86

This feels perhaps like a silly comment, but I have this intuition that the data collected by JWST could prove to be some of the most important ever collected.

People (including me!) really don't have a feel for just how far some of these instruments push things.

The Hubble Deep Field was a surprise to quite a few established astronomers. LIGO is measuring things way smaller than nucleons. The JWST can see so far back in time hat you can measure deltas from the beginning of the visible universe.

I know that I just don't have an appreciation for just how hard these things are to do.

Re: James Webb is fully deployed

#353

Post by dredmorbius »

weaksauce wrote: post #275
dredmorbius wrote: post #239

Earlier quoted context omitted.

Yes. Those adjustments, as well as unloading of the reaction wheels used to position JWST, and the fuel burns reqiured for them, are the principle determinants of the JWAT's lifespan, estimated at 10 years. Nasa have lowballed such estimates for numerous missions in the past (Hubble and numerous Mars lander and rover missions come to mind), and it's possible JWST will exceed the planned lifetime, potentially by a wid…

I was under the impression that they were planning on making a drone that would refuel it in 10 years or so? Is that not correct?

I've heard that the capavility exist but the mission is not planned.

https://www.space.com/3833-nasa-adds-docking-capability-spac...

https://jwst.nasa.gov/content/about/faqs/faq.html#serviceabl...

Re: James Webb is fully deployed

#354

Post by dmead »

JohnBooty wrote: post #349
dev_tty01 wrote: post #345

Earlier quoted context omitted.

Yes, I get all of that, but they still missed an excellent PR opportunity. NASA really could have built some engagement showing images of the deployment process, even if the images wouldn't have direct scientific benefit. Good PR leads to improved funding which leads to more science.

I just want to make sure I understand. Your position is that they should have added significant complexity to a maneuver that was already the most complex of its kind. A maneuver with $10 billion and two decades of work on the line. In order to make the first 30 days of a 10+ year mission marginally more entertaining. You propose this while fully aware that the "entertainment" in question consists of things unfolding…

Literally every other nasa mission is filmed like this now. 10 billion and we can't even get visual confirmation it's doing well.

And yes. Hubble being deployed was a big deal.

Re: James Webb is fully deployed

#355

Post by sailingparrot »

WalterBright wrote: post #312
WalterBright wrote: post #75

Since 90% of the cost is probably in R+D of the telescope, one could build and deploy another for another 10%. Why isn't this done? Why is every space telescope completely unique?

After reading all these replies, I'm glad Musk never listened to people who said he couldn't make a cheap, reliable rocket that could land on its tail. grump, grump, grump

Your point is completely unfair.

Sure if our goal was to mass manufacture a "cheap and reliable JWST" we could, with a lot of money, create an entire assembly line and benefit from economies of scale. And then what? What are we supposed to do with 100s of JWST? It's cool they only cost 200M$ each now, but we don't need them.

What we need after JWST is a different telescope with different technologies to answer questions that JWST cannot answer and to follow up on the discoveries from JWST.

SpaceX and Boeing are responding to a scale problem: getting as much mass as possible into space, getting as much people as possible from point A to B. You solve a scale problem with scale.

JWST is science instrument, looking for answer to specific questions, once those answer are found we will want a different instrument to answer different questions. Scale does not help. Multiple JWSTs cannot see what a single one can't.

Re: James Webb is fully deployed

#356

Post by phire »

weaksauce wrote: post #275
dredmorbius wrote: post #239

Earlier quoted context omitted.

Yes. Those adjustments, as well as unloading of the reaction wheels used to position JWST, and the fuel burns reqiured for them, are the principle determinants of the JWAT's lifespan, estimated at 10 years. Nasa have lowballed such estimates for numerous missions in the past (Hubble and numerous Mars lander and rover missions come to mind), and it's possible JWST will exceed the planned lifetime, potentially by a wid…

I was under the impression that they were planning on making a drone that would refuel it in 10 years or so? Is that not correct?

They have given it a 10 year lifespan. They have said that fuel is a major limiting factor and talked about a refuelling drone to extend life.

But I don't think that means it only has 10 years of fuel, and I don't think they have ever said explicitly said that. I suspect it's more like 15 years in the best case.

The fact that they aren't already planning a refuelling mission implies that it's not a critical limiting factor.

Re: James Webb is fully deployed

#357

Post by galacticaactual »

JohnBooty wrote: post #349
dev_tty01 wrote: post #345

Earlier quoted context omitted.

Yes, I get all of that, but they still missed an excellent PR opportunity. NASA really could have built some engagement showing images of the deployment process, even if the images wouldn't have direct scientific benefit. Good PR leads to improved funding which leads to more science.

I just want to make sure I understand. Your position is that they should have added significant complexity to a maneuver that was already the most complex of its kind. A maneuver with $10 billion and two decades of work on the line. In order to make the first 30 days of a 10+ year mission marginally more entertaining. You propose this while fully aware that the "entertainment" in question consists of things unfolding…

What a condescending reply.

That 10 billion was funded by taxpayers, and the assertion that at the very least there should have been a possibility of those taxpayers seeing the fruits of their money through pictures instead of some intractable telemetry is a fair one.

Re: James Webb is fully deployed

#358

Post by mturmon »

freeflight wrote: post #346
bichiliad wrote: post #250

Earlier quoted context omitted.

One thing they mentioned that kinda sends it home to me is that the telescope is aimed at the dark and away from the sun, and the other side is especially reflective[0]. In other words, one side is too dark to see, and the other is too bright to see. [0]: https://twitter.com/NASAWebb/status/1479161991252131841

> the telescope is aimed at the dark and away from the sun To be more specific; It's "parked" in an orbit [0] that constantly puts Earth between the sun and James Webb. So it's not only aimed away from the sun, Earth is also acting as a planetary scale sunscreen for it. [0] https://en.wikipedia.org/wiki/Lagrange_point

JW does indeed circle that Lagrange point, but it is definitely not in Earth’s shadow.

The JW orbit semi major axis (about the L2 point) is order of 500,000 km. The radius of Earth is about 6500 km. Thus, the shadow of the Earth is extremely small compared with the excursions of JW.

Re: James Webb is fully deployed

#359

Post by geraldyo »

ThalesX wrote: post #216
brink wrote: post #58

I've never been one for being hyped about telescopes, but I am particularly excited about the images that this one will come up with.

What kind of images can we expect? I understood it's an infrared telescope. Will we get visually ... interesting images? Or just data?

Public perception is always part of big budget projects like this. They are most likely releasing some outstanding "enhanced" visually interesting images

Re: James Webb is fully deployed

#360

Post by JshWright »

samstave wrote: post #327
JshWright wrote: post #313

Earlier quoted context omitted.

All you would be able to see is the sunny side of the sun shield, none of the cool (both literally and figuratively) bits, which are all in darkness.

I have a few questions about extending a tethered "selfie bot" If you have a tethered camera which uses the tether as its power source which is out in front of the scope, wouldn't it be able to "stare" back at the Business Side of the mullet and stream the Party back to earth? Or does a teathered bot risk messing with the orbit of the scope? How much actual pull strength is requireed per kilo to re-orient something i…

But what would the point be? All the interesting bits are in effectively total darkness.
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