OT: Successful launch for the James Webb telescope

Submitted by k1400 on December 25th, 2021 at 6:24 PM

After 25 years the James Webb telescope is on its way to the L2 Lagrange point.  Nice Christmas present for a lot of NASA people.  Lot of work to go yet before it's fully functional.  

Here's a cool video about the engineering that went into it:

https://www.youtube.com/watch?v=aICaAEXDJQQ

Sopwith

December 25th, 2021 at 7:01 PM ^

The terrifying part is going to be the unfolding of the solar shield (the size of a tennis court). Any of that goes wrong, and it's just a hunk of unrepairable space junk.

dragonchild

December 25th, 2021 at 8:46 PM ^

All five layers of the shield (if any are damaged the telescope will be blinded by thermal noise), plus the solar panels, and the mirrors. To get it to fit inside a rocket, it’s basically a transformer.  And if anything fails to deploy perfectly, there ain’t no repair mission going out to L2.

k1400

December 26th, 2021 at 12:00 AM ^

And that shield is going to be unfurled for the majority of the trip out to L2.  Guess they need the benefit of the heat shield well before parking in orbit to justify exposing it to possible damage en route.  Each of the 5 layers is hundredths of a millimeter thick.  Fingers crossed for a clear path!

1VaBlue1

December 26th, 2021 at 9:05 AM ^

The sun shield is needed to cool down the cameras and various science instruments so they can start calibration once safely inserted into the L2 orbit.  To avoid seeing their own IR shadow, the cameras need to be below 40° Kelvin (~ -380° F), while the Mid-IR Instrument (MIRI) cameras have to be below 4° K (-488° F).  So yeah, the sun shield is pretty important!

Interesting tidbit - the vehicle only has thrusters that push it away from the sun.  The L2 point is quasi-stable, where the sun and Earth have ~equal gravitational pull.  And the cameras will always be pointed away from the sun as it rotates the sun with the Earth in between.  As the sun pulls it back some, the thrusters will have to occasionally fire to push it back out - but not too far.  If it goes too far, it'll keep sailing out into space and be lost forever.  Fail to fire, and it'll be inexorably pulled into the sun.  So the A5 rocket intentionally sent it out to L2 at too slow a speed to actually reach the point, which is why it'll require three burns to get there.  Don't want to overrun the insertion into L2 orbit!

Source: an old Navy friend that is a mission controller for some of the camera color guns.

Grampy

December 25th, 2021 at 8:38 PM ^

It’s gonna hurt to keep my fingers crossed for the next two months.  Lots of things have to work right before we’re home, but what a spectacular home!

Wally Llama

December 25th, 2021 at 9:31 PM ^

I get that it will be a while before its fully operational, but I'm having a hard time containing my inner toddler jumping up and down and pouting, "But I want it to work NOOOOOOWWWWWW!!!

ShadowStorm33

December 25th, 2021 at 10:30 PM ^

Anyone else think it's kind of strange that they launched it on Christmas? Seems like it kind of sucks for all the NASA employees that otherwise could have been spending time with their families...

IYAOYAS

December 26th, 2021 at 1:11 AM ^

I’ve been in similar situations and missing whatever holiday doesn’t hold a candle to  executing the mission. Some things are bigger than our enjoyment or convenience. 

Oddly enough, the holiday can still serve as a quirky backdrop for the mission. And after the shot you can always find camaraderie and usually an open bar. 

1VaBlue1

December 26th, 2021 at 9:12 AM ^

I know one of the mission controllers that was at the mission control center in Baltimore yesterday morning, and I can assure you that nobody was upset to finally be launching this thing.  They had a big huge good time when they finally got control after separation from the rocket.  Its what they worked for, for so many years.  The pictures he sent were nothing but ear to ear smiles and laughter...

ShadowStorm33

December 25th, 2021 at 10:30 PM ^

Anyone else think it's kind of strange that they launched it on Christmas? Seems like it kind of sucks for all the NASA employees that otherwise could have been spending time with their families...

BlueDragon

December 26th, 2021 at 1:31 AM ^

I have fond memories of Hubble going into low Earth orbit and telling us so much about the universe around us. Even when it needed 'glasses' and a repair mission. Onward, Webb.