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James Webb is fully deployed

nasa.gov

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Re: James Webb is fully deployed

#301

Post by WalterBright »

mlyle wrote: post #162
WalterBright wrote: post #119

Earlier quoted context omitted.

Assuming your figures are correct, you'll get double the data for another 30% cost. If you wait a month before launching #2, if problems appear in #1 (like the telescope mirror was ground improperly) it can be fixed in #2. The operational cost will not double. The same ground facility, equipment, and staff can manage both. If you're buying two identical launches, you can get a quantity discount. > the benefits of a s…

> Assuming your figures are correct, you'll get double the data for another 30% cost. I think 30% is probably a reasonable guess, based on past programs where people have flown 2. You get to reuse design and some fixturing. You get to share some operational costs. But you're not at unit counts where you benefit from mass production techniques and a whole lot of verification and qualification work are still effectivel…

Another poster here remarked that spares would be made. That would indicate the cost of doing so isn't that remarkable.

Re: James Webb is fully deployed

#302

Post by luxuryballs »

daveslash wrote: post #204
jl6 wrote: post #192

More great news. Congratulations to all who have worked on the project. I understand the reasons for not putting a camera on or near the JWST, but I’m still a little sad that we’ll probably never get to see the thing in situ in all its operational glory. Maybe one day when it finally expires, we can launch a “sample return” mission to tow it back.

RE>> "I understand the reasons for not putting a camera on or near the JWST" What are the reasons? I'm sorry ~ I'm ignorant on the topic, but I'd love to learn more. Why/what are the reasons?

Looks like there aren’t actually any good reasons. I’m actually kind of surprised that mere curiosity at what could have been seen wasn’t good enough.

Re: James Webb is fully deployed

#303

Post by terramex »

xvector wrote: post #280
weaksauce wrote: post #272

Earlier quoted context omitted.

the plan as i understand it is to have a drone refuel it after about 10 years or so... that might have a camera on it perhaps?

I thought there were no plans for any refuel or repair mission.

There are no plans at the moment because it is not even clear how long will current fuel supply last. NASA engineer today said "maybe 20 years, roughly speaking", my back-of-napkin math says that it could be up to 30 if everything goes great. It will depend on exact schedule of observations, number of unexpected transient observations and solar activity. Computer simulations of its orbit and solar wind pressure have some error bars that will be corrected once we get solid data. It also has funding for only 5 years of ground operations right now. Once the mission get extended and we have solid understanding of how it behaves in space we could think of designing refuelling mission. It has fuel port so it is possible in principle, but I don't expect any concrete plans within 10 years.

Re: James Webb is fully deployed

#304

Post by WalterBright »

bumby wrote: post #215
WalterBright wrote: post #205

Earlier quoted context omitted.

So build a copy out of the spares! If they're there, they're already paid for.

Not every part meets the criteria to be a "critical" spare. You don't have a complete set of spares for every component.

Are you suggesting that spares are only produced for the cheap parts?

Re: James Webb is fully deployed

#305

Post by physicles »

lovecg wrote: post #210
baq wrote: post #197

Earlier quoted context omitted.

About 0. It’s climbing a hill and has just enough energy to get to the top. A small burn then will be all it takes to put it in an orbit around L2.

It also needs to get as close as possible to the top of the hill without going over. L2 is not a stable point: you’re either falling back to Earth or drifting away. If it goes over it can never get back as it can only fire in one direction - away from Earth (to protect the instruments from the Sun). So it’s a continuous balancing act where it falls downhill towards Earth a bit, then jumps up without going over the ed…

This answers a question I’ve had for a long time: how can the telescope station-keep without any thrusters pointing “up”, away from the sun? Answer: very, very carefully.

Re: James Webb is fully deployed

#306

Post by terramex »

jordanpg wrote: post #288

I understand that it will take months to perfect the primary mirror alignment and focus for good science data, but when can we expect the first image?

> Some high priority scientific observations (GTO & GO) with the JWST are likely to be carried out during the commissioning period, since it is clearly desirable to begin to take science data as early as is technically feasible.

> Early Release Observations (EROs) will be taken by JWST during both the commissioning and post-commissioning phases of operation. These observations will be chosen to have wide public appeal and are designed to demonstrate the capabilities of the JWST instruments. Publication or reporting in any form of results of these observations is embargoed until the EROs are released.

https://jwst-docs.stsci.edu/jwst-opportunities-and-policies/...

There is a chance for first images to be released before commissioning is complete, but no dates announced so far.

Re: James Webb is fully deployed

#307

Post by richardwhiuk »

finnh wrote: post #237
ascar wrote: post #199

Earlier quoted context omitted.

I didn't check for sources again earlier, but this NASA article [1] explains it. Yea shadow was the wrong word and doesn't actually apply because of the relative size of the sun and earth. However the L2 point is by definition in a straight line Sun -> Earth -> L2, so if the sun would be a single point light source that would block the sun and place the JWST in the permanent shadow thrown by the earth. The point is a…

It's orbiting L2, not at it. It will have basically constant sunshine, which is good - solar panels provide all its power. (no RTG)

It has constant sunshine on one side, and constant darkness on the other.

Re: James Webb is fully deployed

#308

Post by Ostrogodsky »

terramex wrote: post #303
xvector wrote: post #280

Earlier quoted context omitted.

I thought there were no plans for any refuel or repair mission.

There are no plans at the moment because it is not even clear how long will current fuel supply last. NASA engineer today said "maybe 20 years, roughly speaking", my back-of-napkin math says that it could be up to 30 if everything goes great. It will depend on exact schedule of observations, number of unexpected transient observations and solar activity. Computer simulations of its orbit and solar wind pressure have…

Yeah, I think that will depend on the scientific quality of the observations provided by JWST:

- Hubble/COBE level. Refuel it!

- LHC level: Meh, let it rot.

Tbf it is less about the device (and the people working on it) and more about what kind of fundamental changes to our understanding of the universe is provided by its observations. BTW I am pretty bullish on that front.

Re: James Webb is fully deployed

#309

Post by heavyset_go »

behnamoh wrote: post #285
JohnBooty wrote: post #208

Earlier quoted context omitted.

Great blog post from NASA themselves explaining it: https://blogs.nasa.gov/webb/2022/01/06/why-doesnt-webb-have-... the post is really not very long and I would suggest getting it straight from the horse's mouth, but for those not willing to devote a click here are arguably the most relevant bits! "deployment surveillance cameras would not add significant information of value for engineering teams commanding the spac…

they could have sent a temporary camera along with the craft to take a picture of it at the final position and send back to earth.

Sounds like that would be expensive with little to no return when it comes to the goals of the mission.

Re: James Webb is fully deployed

#310

Post by samstave »

jl6 wrote: post #192

More great news. Congratulations to all who have worked on the project. I understand the reasons for not putting a camera on or near the JWST, but I’m still a little sad that we’ll probably never get to see the thing in situ in all its operational glory. Maybe one day when it finally expires, we can launch a “sample return” mission to tow it back.

Why dont we deploy a smaller sat in the same-ish orbit thats only job is to be the RING Doorbell for the JWST -- all it does is stream a live-stream back of the JWST -- if we can freaking deploy streams of Starlink (SKYNET) devices - we can certainly place tele-photo-capable sats that can then provide streaming video back of the things they are walking -- and they can FN relay off the starlink (SKYNET) devices...
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