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James Webb Space Telescope

Started by Alberon, December 24, 2021, 12:17:20 AM

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Alberon

After about a quarter of a century of development the next generation in space telescopes, the James Webb, is planned to be launched on Christmas Day.



It will view light mainly in the mid-infrared range which are longer wavelengths than the Hubble space telescope can observe. This means that the James Webb should be able to see objects that are more red-shifted than the Hubble, that is objects farther away which emitted light closer to the birth of the universe.

The mirror is made up of hexagons of gold-plated beryllium and is much larger than Hubble's.



Unlike the Hubble it won't be in Earth orbit, but will instead be based at the Lagrange Point 2.



At L2 the Earth will be between the telescope and the sun, but while the orbit is wider than Earth's being at the L2 point means it will orbit the sun in one year. Though that will involve some station keeping and the thrusters will run out of fuel in just ten years. And unlike the Hubble, astronauts will not be able to go to it to refuel it.

The telescope needs to be extremly cold to work properly so moving so far away from the Earth allows a heatshield to block out all sunlight and reflected Earthlight so it can achieve the -223 degrees centigrade operating temperature.

If all goes according to plan the telescope should be able to see back to near the dawn of the universe when the first stars started to shine.

But it's a big if. The launch needs to go perfectly, the weeks long journey to the L2 point has to be achieved, the mirror deployed, and the sunshield fully open.

It is one of the most expensive and most important space projects ever. If it works it will revolutionise our view of the universe just as Hubble did.

So, fingers crossed!

bgmnts

Would love it if whoever looks into this telescope sees some Event Horizon shit and goes insane.

Or god with his willy out helicoptering.

touchingcloth

It's worth pointing out that it's going to be really far from earth. The ISS is at 420km, Hubble at 540km, the moon at 400,000km, but JWST will be at 1,500,000km.

Johnny Foreigner

They'll never make a sufficiently long cable.

idunnosomename

i remember watching NASA public outreach videos literally twenty years ago and they were talking about this fucking thing. also isnt James Webb a nonce or something

Johnny Yesno

Quote from: Johnny Foreigner on December 24, 2021, 01:00:58 AMThey'll never make a sufficiently long cable.

Imagine if you bought one of these so-called 'telescopes' and it turned out you were wrong to assume that 'remote controlled' meant radio controlled. Anyone of a certain vintage knows that pain.

Quote from: idunnosomename on December 24, 2021, 01:04:41 AMalso isnt James Webb a nonce or something

Don't you mean 'boffin'?

Sebastian Cobb

Keep misreading this as 'James Whale telescope'.

mothman

I didn't realise it was going to be at a Lagrange point. Is this the first time anything has ever been sited there?

idunnosomename

Quote from: mothman on December 24, 2021, 01:24:33 AMI didn't realise it was going to be at a Lagrange point. Is this the first time anything has ever been sited there?
a haw haw haw

idunnosomename

sorry no James Webb was not a paedophile (it seems) but he was complicit in the purge of LGBT individuals from government office

https://en.wikipedia.org/wiki/Lavender_scare

Blumf


Fr.Bigley

I'd use it to spy on some high quality alien tits 

Replies From View

Quote from: Fr.Bigley on December 24, 2021, 09:10:25 AMI'd use it to spy on some high quality alien tits 

Would you settle for low quality

Fr.Bigley

Quote from: Replies From View on December 24, 2021, 09:26:44 AMWould you settle for low quality

If there were three of them, like in total recall.

Alberon

Quote from: mothman on December 24, 2021, 01:24:33 AMI didn't realise it was going to be at a Lagrange point. Is this the first time anything has ever been sited there?

Apparently there's been a few bits and pieces.

If it makes it the telescope won't be the first to L2.

https://en.wikipedia.org/wiki/List_of_objects_at_Lagrange_points

Fr.Bigley

They should rename it the ZZ Top point.


Replies From View

Quote from: Fr.Bigley on December 24, 2021, 10:02:08 AMIf there were three of them, like in total recall.

What if it was just one really awful one

WhoMe

The engineers and designers must be absolutely cacking themselves. A lifetime's work, potentially scuppered by a single hinge getting jammed or something. Do hope it goes smoothly, but the Hubble was fucked when they initially launched it and this is a thousand times more complicated. 

Replies From View

Can they try putting it relatively nearby first so that they can still reach it to fix anything?


We've all flung a frisbee into a tree and had to go home without it - the failure of this space telescope scenario would probably be twice or even three times as deflating.

Fr.Bigley

Quote from: Replies From View on December 24, 2021, 10:24:53 AMWhat if it was just one really awful one

Probably still manage it, to be honest.

Alberon

Apparently they have a manoeuvre planned if the sunshield doesn't fully open. They're going to use the thrusters to shimmy the craft which will hopefully dislodge anything that's jammed.

Quote"For most missions, launch contributes the majority of mission risk," explained Thomas Zurbuchen, the associate administrator for science missions at NASA. "If the spacecraft is in space, most risk is behind us."

However, there are exceptions to this rule, Zurbuchen explained in a new blog post for the space agency. For the Mars Perseverance mission launched last summer, for example, only about 10 to 20 percent of the mission's risk was retired once the spacecraft reached orbit. The remainder lay ahead of the vehicle, particularly with its daring landing on Mars, and then performing a technically challenging sample acquisition and analysis.

The $10 billion James Webb Space Telescope, due to launch on a European Ariane 5 rocket late this year, offers an even more extreme example. In his blog post, Zurbuchen offers a frank and revealing analysis of Webb's launch and assessment of the risks.

Once in space, Webb will need to travel about 1.5 million km from Earth to the L2 Lagrange Point beyond the Moon where it will be able to maintain a stable position without using much on-board propulsion. Along the way, and once there, some 50 deployments of the large, folded-up telescope will be necessary to prepare for scientific observations. This process will involve nearly 350 single-point failures, and if something goes wrong, it would scuttle the deployment without hope of repair. The number of single-point failures for Webb, by comparison, is a factor of three greater than the seven-minute landing of Perseverance on Mars.

It will take about three weeks to deploy Webb, and scientists will be on edge the entire time, Zurbuchen said.

"Those who are not worried or even terrified about this are not understanding what we are trying to do," Zurbuchen wrote.

Endicott

Quote from: touchingcloth on December 24, 2021, 12:34:01 AMIt's worth pointing out that it's going to be really far from earth. The ISS is at 420km, Hubble at 540km, the moon at 400,000km, but JWST will be at 1,500,000km.

This is about the same as the radius of a Culture Orbital, scale fans.


TrenterPercenter

It must be said I'm very excited about this telescope and all the new pretty pictures it will bring.  Something to look forward to in the NY!

touchingcloth

Quote from: Endicott on December 24, 2021, 10:48:19 AMThis is about the same as the radius of a Culture Orbital, scale fans.

Is it? I wouldn't banks on it.

bgmnts

Just as non scientist not really familiar with space and stuff, will anything we learn from all this work help solve any of the problems on our planet?

touchingcloth

I just want to say that I am a fan of @Alberon's space posts, long may they continue.

touchingcloth

Quote from: bgmnts on December 24, 2021, 11:06:21 AMJust as non scientist not really familiar with space and stuff, will anything we learn from all this work help solve any of the problems on our planet?

Yes. The problems of finding out what happened in the early universe.

bgmnts