James Webb Telescope Launch (finally)

eg2505 said:
anything can happen during/after launch, what if the rocket blows up?
start from scratch?
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Yes, things can happen. That's why they were shitting bricks on launch.


What exactly is your agenda here - complaining that they didn't build a$10 billion second one that isn't required right now?
 
eg2505 said:
why such a mistrust, because things, can and do happen especially when so many things all have to work in harmony,
your sending a finely crafted spacecraft into the great unknown, sure you've designed X,Y and Z for it to survive, but something can still crop up nobody foresaw.

all I want to know is if something goes wrong, what can they do?
only software fixes from this point forward, and nothing else? so if a Micrometeorite smashes into the mirror, and renders the entire thing worthless?

what then? whats the backup plan?
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There is none, just like there was none with Voyager 1 and 2 and all the probes we sent to the Moon/Mars and beyond. Right now we cannot even fix a satellite in low earth orbit because we retired the shuttle. Once something leaves our atmosphere, it either works OR it is junk.
eg2505 said:
anything can happen during/after launch, what if the rocket blows up?
start from scratch?
Click to expand...
Launch vehicles do blow up sometimes, and yes, you then start over.
 
I think Hollywood has confused as well. The space stations usually have an escape plan, no other space mission has any major back-up plan that I've ever heard of. Hubble was lucky with its location and timing in history, that's all.

That includes any new trips to the moon AFAIK, if it fails they ain't coming back, period.
 
Gordon_R said:
This isn't a GoPro, can't expect instant results... /s

It is a mistake to think of astronomy as taking pictures. That era peaked in the mid 20th century. Recent telescopes show improvements in sharpness and light-gathering, but most research since then has been spectroscopy. Pretty images are a mostly a by-product for PR reasons.
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@RiaX,

If you want to understand this in more detail, a trip and visit to Sutherland, followed by a visit to the SKA project is the way to get a small taste of what is involved and how exciting all this.

Besides, don't worry this is not quasi-science like most of the medical research going on, no double-blind placebo-controlled crap requiring peer-review. And the Twitter Nerd, like most of the rest of us, has no chance in hell of getting to grips with the maths and stats involved.
 
Brian_G said:
Absolutely a danger, sure.
What I've seen them doing so far in their live broadcasts of deployments is pause for every line of code which is actually created here according to a script, examine it by at least one other, approve it, and then the on-board computer asks for it to still be confirmed.
As I said, anal.


No round trip is / was possible as it's too complex and limiting for that distance.
As for a robot, still too far in the future for any kind of such normal service. It would be a separate mission of its own and both expensive and useless if not needed.
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Much easier to simply build a new one.
 
eg2505 said:
so there is a Dummy one down on Earth? or they never built it, they just assumed its gonna work with the amount of cash they paid for it.
even the Mars Rovers have Twins down on Earth, that could conceivably be flight readied and sent out should something catastrophic happen.

Like a Rocket blowing up or a comma in the code somewhere crashes the entire system.
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The sw writers employed on this project are far more capable than the lot that write code we all suffer under from day-to-day. The code was developed using really sound methodologies and tested over and over again.
And they sure as hell were not selected from 30% matric pass groups.
 
Not to take away from all the scientists & everyone else's achievement, but to think ol'e Webb was anti-LGBT+ yet now his telescope is destined to stare at all those ancient black holes for the duration of its life..

The universe certainly has an ironic sense of humour.
 
eg2505 said:
anything can happen during/after launch, what if the rocket blows up?
start from scratch?
Click to expand...
Yes. Many satellite projects (especially the budget ones launched by minor countries) have absolutely no backup plan, no in-orbit spare or no on-the-ground spare. The ONLY satellite organisation that used to have a backup plan was Intelsat.
 
gregmcc said:
This is why it was delayed and took so long to build. Test test test and more testing as once it's launched there is no going back.
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My thought at reading about it's intended lifespan due to limited fuel & not able to service it after its in orbit, was that they should've made it so it can be refueled remotely, I mean we plan to land probes on asteroids 10 years in future with success, and lo & behold I read the following..
Webb may have as many as 20 years of fuel — the physical parameter that defines mission lifetime — available due to the precision of its flight path to L2 expending far less fuel than anticipated. Webb was also built so that it could be refueled robotically. Both of which means Webb could be around for a long while — perhaps as long as 32-year old HST.
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Man, think of the brainpower & effort that went into this thing, clever and dedicated people making stuff work against all odds.
 
Geoff.D said:
Yes. Many satellite projects (especially the budget ones launched by minor countries) have absolutely no backup plan, no in-orbit spare or no on-the-ground spare. The ONLY satellite organisation that used to have a backup plan was Intelsat.
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I would know with what the Israelis launched,
www.spaceil.com

Home | spaceIL

SpaceIL is a non-profit organization that strives to promote science and science education. In April of 2019, SpaceIL became the first private entity in history to reach the moon, whereby positioning Israel as the seventh country to reach the moon.
www.spaceil.com www.spaceil.com

that failed, but they'll be back I'm sure.
 
One "mistake" with Wiki page seen - they speak about the up to 100 times improvement of Webb's imaging over other efforts, but somewhere from NASA I read that as far as the mid-infrared detecting goes, some of it will be up to a 1000 times improvement!
-------------------------------------------------------


This from NASA's blog yesterday (now mostly just weekly updates) ;

Webb Begins Its Months-Long Mirror Alignment​

Webb has begun the detailed process of fine-tuning its individual optics into one huge, precise telescope.

Engineers first commanded actuators – 126 devices that will move and shape the primary mirror segments, and six devices that will position the secondary mirror – to verify that all are working as expected after launch. The team also commanded actuators that guide Webb’s fine steering mirror to make minor movements, confirming they are working as expected. The fine steering mirror is critical to the process of image stabilization.

Ground teams have now begun instructing the primary mirror segments and secondary mirror to move from their stowed-for-launch configuration, off of snubbers that kept them snug and safe from rattling from vibration. These movements will take at least ten days, after which engineers can begin the three-month process of aligning the segments to perform as a single mirror.
 
I wanted to ask something technical,

why isn't this spacecraft powered by a RTG? I mean why go through with the whole complicated unfolding and hot and cold zone insulation and all the rest of it,
when a simpler solution used by the Mars rovers exists already, a Much simpler solution that's proven to work reliably for Centuries.

I mean Voyager 1 and 2 still operating till today near the edge of the Solar system
 
RTG = Radioisotope Thermoelectric Generators

eg2505 said:
I wanted to ask something technical,

why isn't this spacecraft powered by a RTG?
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Maybe it's the way you phrase your questions, but really, why do you continue to critically question the whole collective of scientists and engineers involved??

When it comes to the curiosity factor, I have no idea why and would also be interested to know. Maybe a contamination issue, and I'm sure heat could be a problem.
Have you considered sending them a Tweet? (I don't use Twitter.)

eg2505 said:
I mean why go through with the whole complicated unfolding and hot and cold zone insulation and all the rest of it...
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How do you think a RTG power source is going to end the need for this special and extreme insulation? Maybe read more about it, not something a simple freezer will achieve.
 
Brian_G said:
RTG = Radioisotope Thermoelectric Generators


Maybe it's the way you phrase your questions, but really, why do you continue to critically question the whole collective of scientists and engineers involved??

When it comes to the curiosity factor, I have no idea why and would also be interested to know. Maybe a contamination issue, and I'm sure heat could be a problem.
Have you considered sending them a Tweet? (I don't use Twitter.)


How do you think a RTG power source is going to end the need for this special and extreme insulation? Maybe read more about it, not something a simple freezer will achieve.
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why do I continue to be critical, because the price-Tag seems a bit extreme to me, far better uses for something with that sort of money,
for instance, better Fiber optic manufacturing in Microgravity environments. Moon outposts, human colonization in orbit.

and the RTG is just a question, an interesting one if electricity supply is such a issue in Orbit,
 
eg2505 said:
why do I continue to be critical, because the price-Tag seems a bit extreme to me, far better uses for something with that sort of money,
for instance, better Fiber optic manufacturing in Microgravity environments. Moon outposts, human colonization in orbit.
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That I can understand. But not firm second-guessing their systems choices.

Anyway, hopefully someone can add facts to our reasoning :- )
 
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