News: 1638838125

  ARM Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life (Terry Pratchett, Jingo)

It's primed and full of fuel, the James Webb Space Telescope is ready to be packed up prior to launch

(2021/12/07)


Engineers have finished pumping the James Webb Space Telescope with fuel, and are now preparing to carefully place the folded instrument inside the top of a rocket, expected to blast off later this month.

“Propellant tanks were filled separately with 79.5 [liters] of dinitrogen tetroxide oxidiser and 159 [liters of] hydrazine,” the European Space Agency [1]confirmed on Monday. “Oxidiser improves the burn efficiency of the hydrazine fuel.” The fuelling process took ten days and finished on 3 December.

All eyes are on the JWST as it enters the last leg of its journey to space; astronomers have been waiting for this moment since development for the world’s largest space telescope began in 1996.

[2]

The $10bn project is the most complex and ambitious attempt to launch an observatory beyond Earth yet. Measuring about the size of a tennis court, its 6.5-meter-long panel of 18 hexagonal gold-coated beryllium mirrors sits on top of a large sunshield. It’s bigger than NASA’s Hubble Space Telescope, and wider than the Ariane 5 rocket taking it to space. The whole thing will have to be neatly folded and packed away during launch.

[3]

Over the next few weeks, the teams behind the telescope and the rocket will work together to place the giant observatory inside its launch vehicle. It’ll then be carted away for final testing before it launches from the spaceport in French Guiana [4]as soon as Wednesday, Dec 22, at 0720 EST.

[5]James Webb Space Telescope may actually truly launch this century, says NASA

[6]31-year-old piece of hardware not working very well: Hubble telescope back in safe mode over 'synchronization issues'

[7]James Webb Space Telescope completes its voyage to French Guiana

[8]James Webb Space Telescope penciled in for launch this century. Yes, Dec 18, 2021

Once it leaves terra firma to get to its final destination 1.5 million kilometres (930,000 miles) away, a region known as the Earth-Sun L2 Lagrange point, mission control will kickstart a series of steps to slowly unfurl the telescope bit by bit. Everything has to work perfectly, humans will not be able to service the JWST at that distance. It won’t be fully deployed until 30 days after launch, as the video below demonstrates.

[9]Youtube Video

Unlike Hubble, the new telescope will observe light sources at wavelengths of 60 to 500 microns in the infrared spectrum. It’s large mirror means it'll be able to focus light at further distances and peer at the universe over 13.5-billion years ago, during a time when the first stars began to form, allowing astronomers to see wider and deeper into space than ever before. ®

Get our [10]Tech Resources



[1] https://www.esa.int/ESA_Multimedia/Images/2021/12/Webb_fuelled_for_launch

[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2Ya7qjBiO6S3SITT7onZgjgAAAE8&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0

[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44Ya7qjBiO6S3SITT7onZgjgAAAE8&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[4] https://www.theregister.com/2021/11/29/jwst_launch_date/

[5] https://www.theregister.com/2021/11/29/jwst_launch_date/

[6] https://www.theregister.com/2021/10/26/hubble_safe_mode_again/

[7] https://www.theregister.com/2021/10/13/jwst_french_guiana/

[8] https://www.theregister.com/2021/09/09/james_webb_telescope/

[9] https://www.youtube.com/watch?v=RzGLKQ7_KZQ&t=2s

[10] https://whitepapers.theregister.com/



Mark 85

That certainly doesn't sound like much fuel. Anyone know how long they expect it to last since re-fueling isn't an option?

eldakka

Design lifetime is at least 5.5 years.

Hopeful of 10 years.

Assuming there are no actual failures that reduce its life (non-redundant systems breaking for example), it'll depend on how much fuel it will need for stationkeeping. The L2 is not 100% stable, it requires regular adjustments to maintain orbit around it. So there's a lot of educated guesswork in how much fuel they'll need. So they've put enough fuel for a worst case station-keeping fuel usage for 5.5 years, which will of course last longer if their worst-case estimates were too pessimistic, so they are hoping for ~10 years, maybe more, but only 'guarantee' 5.5.

Bon voyage

HildyJ

Now that the Ariane upper stage has been mounted, telescope has been mounted to the upper stage adapter (the kerfuffle when the clamp slipped), and the telescope has been fueled, the major sphincter tightening points before launch are securing the fairing around the telescope, mounting the telescope assembly on the Ariane upper stage, moving the Ariane to the launch pad, fueling it, static testing it, refueling it, and blastoff.

We're not out of the equatorial rain forest yet but I have faith in the boffins.

What a long strange trip it's been.

Why so long to fill?

Sleep deprived

Why does it take 10 days to fill 238 liters of fuel and oxidizer? This is a genuine question.

Re: Why so long to fill?

msobkow

Well, among other things, unlike in a car, a bubble in a rocket's fuel tanks can have explosive consequences...

I am feeling two conflicting emotions

eldakka

I'm so excited I could pee my pants.

I'm so terrified that something goes wrong I could puke.

"I went to the museum where they had all the heads and arms from the
statues that are in all the other museums."
-- Steven Wright