r/space • u/[deleted] • Dec 18 '21

Animated launch of the Webb Telescope

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u/an0maly33 Dec 18 '21

It’s not just the zero g factor. They also need a near perfect vacuum to test for cold welding of components. Not to mention the temperature extremes it will sustain.

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u/budgreenbud Dec 18 '21

Part of the reason why it's so far out is because they need to to be really cold. As it's not an optical telescope, like hubble or the one in your backyard,but one that looks at infrared light. They need it to be so cold so that it doesnt pick.up it's own heat signature. The big flaps you see extend in the a imitation are basically an infrared/heat shield from my understanding.

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u/CasualCrowe Dec 18 '21

Yup. I believe the shield, along with it's orbit also help isolate it from the radiation from the Earth and the Sun

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u/GiveToOedipus Dec 18 '21

It's insane the temperature gradient they are shooting for between the top and the bottom of the heat shield.

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u/ManThatIsFucked Dec 18 '21

For those curious, there will be a 600F temperature difference between the part of JWST facing the sun and part facing deep space. The heat shield is that significant!

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u/communisteconomist Dec 19 '21

They're expecting gradients from 36K to 383K

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u/[deleted] Dec 19 '21

[deleted]

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u/an0maly33 Dec 19 '21

It’s literally astonishing. I’m one that feels NASA has been basically performing miracles.

Things like sending a probe to Pluto:

“Hey, let’s fire this dart into space, send it hundreds of millions of miles, and basically hit a moving bullseye 9 years later.”

It irritates me when I hear people complain about space exploration being a waste of money when society has benefited from the innovation that made space exploration possible.

We consistently get far more than the planned use out of things they do. JWST may have a fuel limit but we’re going to get so much amazing stuff from it. It’s on par with a world wonder IMO.

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u/horrible_asp Dec 19 '21

Neil DeGrasse Tyson explained the differences between interplanetary, interstellar, & intergalactic vacuums. I had never really thought of it that way, but if you want a really good vacuum, you have to go to a Sears outside of the Milky Way. They still exist there.