Webb telescope gets 'golden touch'

Jul 30, 2012 By Rob Gutro
NASA engineer Ernie Wright looks on as the first six flight ready James Webb Space Telescope's primary mirror segments are prepped to begin final cryogenic testing at NASA's Marshall Space Flight Center in Huntsville, Ala. Credit: NASA's Marshall Space Flight Center/David Higginbotham

(Phys.org) -- NASA technology does some amazing things. Imagine taking one-tenth of an ounce of gold and spreading it so thin that it completely coats something over four feet in diameter. That's what scientists and engineers did for the primary mirror segments that will fly on NASA's James Webb Space Telescope.

The Webb telescope has 18 hexagonal-shaped mirror segments that make up its . Each of the segments is 1.32 meters (4.3 feet) in diameter, flat to flat. Webb Telescope's scientists and engineers determined that a primary mirror 6.5 meters (21 feet 4 inches) across is what was needed to measure the light from faint astronomical sources.

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To enable the mirrors to most efficiently reflect the from say, distant galaxies, a microscopically-thin was needed. Because the Webb telescope is looking at infrared light, gold was the ideal choice because it reflects infrared light so efficiently, especially compared to the reflectivity of bare beryllium. The amazing thing is that Quantum Coating, Inc.'s mirror coating technology allowed just a tiny amount of gold to cover an entire mirror.

"The thickness of the gold coating on the mirrors is only 100 nanometers thick, or a tenth of a micron, which is 1/10,000th of a millimeter," said Paul Geithner, Deputy Project Manager - Technical for the Webb telescope at NASA's Goddard Space Flight Center in Greenbelt, Md. "A human hair is roughly 1000 times thicker."

A new video investigates the technology that layers a micro-thin gold coating on the Webb mirrors.

The video called "Golden Touch" is part of an on-going video series about the Webb telescope called "Behind the Webb." It was produced at the Space Telescope Science Institute (STScI) in Baltimore, Md. and takes viewers behind the scenes with scientists and engineers who are creating the Webb 's components.

During the three minute and 48 second video, STScI host Mary Estacion interviewed people involved in coating the mirrors at Quantum Coating, Inc. in Moorestown New Jersey.

The gold layer coating, only a few millionths of an inch thick, enables the mirrors to best reflect the infrared light the telescope seeks. Credit: NASA's Goddard Space Flight Center/Chris Gunn

Estacion interviews Ian Stevenson, Director of Coating Services at Quantum Coating, Inc. who explained how incredibly small the coating is on the mirror.

In the video, Tyrone Wilson, a Coating Chamber Technician who operated the chamber, explained that the mirrors were coated in special manner called "vacuum deposition." The mirrors are placed in a special chamber where air is removed, and the miniscule amount of gold is vaporized into a cloud. The cloud condenses on the surface of the mirror to form a film. That way, the mirrors obtain maximum reflection.

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User comments : 17

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Moebius
3.7 / 5 (9) Jul 30, 2012
Amazing. Amazing that is if you don't know that gold the size of a piece of gum can be beat out into leaf about the size of a football field. Never ceases to amaze me how little journalists know and yet their business is writing about things.
GSwift7
4.8 / 5 (8) Jul 30, 2012
Amazing. Amazing that is if you don't know that gold the size of a piece of gum can be beat out into leaf about the size of a football field


Yeah, lol. Craftsmen have been doing it since the middle ages, at the very least.

They missed the main point of the story, which is the uniformity of the coating.
Bewia
1.2 / 5 (18) Jul 30, 2012
The point of this story is to gain public interests about JWST, which is of crippled design and it faces shut-down for its immense cost overruns. JWST is an adventurous remnant of Clinton era and a waste of tax payers money in the time, when whole scientific community ignores the cold fusion finding as a single man.
SoylentGrin
5 / 5 (8) Jul 30, 2012
This isn't a piece of gold being beaten into a sheet, though. It's vaporized then deposited in an ultra flat coating. A bit beyond Middle Age craftsmen...
GSwift7
4.6 / 5 (14) Jul 30, 2012
and a waste of tax payers money in the time, when whole scientific community ignores the cold fusion finding as a single man.


cold fusion blah blah blah. Yep, the entire scientific community is in conspiracy to keep the human race enslaved to carbon based fuels. That's because the aliens need to make the climate more hospitable for Them (with a cap T).

You know We (with a cap W) figured out how to see through your foil hats years ago. We are watching you. When you aren't looking, We drive around in invisible flying cars and laugh at you when you are stuck in traffic. Muahhahahaha.
GSwift7
5 / 5 (6) Jul 30, 2012
This isn't a piece of gold being beaten into a sheet, though. It's vaporized then deposited in an ultra flat coating. A bit beyond Middle Age craftsmen


True, but the ancient craft is capable of achieving unbelievable results. Check out the process on the following wiki page:

http://en.wikiped...dbeating

"The finished leaf forms an unbroken sheet of gold with a thickness of 1/250,000 of an inch"

1/250,000 of an inch is 101.6 namometers (according to google unit conversion), and the above process claims 100 nanometers, so basically equivelant except for uniformity, and the fact that it is one continuous piece. The ancient method produces much smaller pieces.

P.S. no jokes about beating allowed
Bewia
2.1 / 5 (8) Jul 30, 2012
the entire scientific community is in conspiracy to keep the human race enslaved to carbon based fuels
I would say, they're in willing ignorance - it would compete the research of alternative methods of energy production/conversion/transport or storage (including the lithium cell research business). The opponents of Galieo were in opposition - but no conspiracy.
There is absolutely no need of some organized conspiracy for it. Or do you feel yourself like some conspirator? You're just an ignorant, one of many and you're not forced to hide your negativist opinion - yet....
El_Nose
5 / 5 (1) Jul 30, 2012
DID SHE TOUCH THE MIRROR IN THE VIDEO ??

talk about scripted
Ms Bitters
not rated yet Jul 30, 2012
About how many atoms thick of gold would the coating be?
El_Nose
5 / 5 (6) Jul 30, 2012
About how many atoms thick of gold would the coating be?


gold's atomic radius is 144pm.

1 pm = 1*10^-12 meter

gold's atomic radius is 144pm = 0.144 nm

100 / 0.144 = 694.444

the layer is 694 atoms thick
Parsec
4.4 / 5 (7) Jul 30, 2012
The point of this story is to gain public interests about JWST, which is of http://www.newsci...pe.html. JWST is an adventurous remnant of Clinton era and a waste of tax payers money in the time, when whole scientific community ignores the cold fusion finding as a single man.


Wrongo buzzard breath. I am ignoring it as a married man. Just celebrated my 25th today. YES!
jsdarkdestruction
3.7 / 5 (6) Jul 31, 2012
interesting. its good to see things seem to be going well. hopefully the launch date wont get pushed back any further. its been far too long of a wait already for me. its so exciting to think of what jwst is going to do and all the things we will learn.
Shinichi D_
4 / 5 (5) Jul 31, 2012
DID SHE TOUCH THE MIRROR IN THE VIDEO ??

talk about scripted


Yeah. I truly hope it was just a mockup for visitors. Or we are about to discover the most distant molecular cloud. :)
Pattern_chaser
not rated yet Jul 31, 2012
Vacuum deposition is well established, yes?
Satene
2 / 5 (4) Jul 31, 2012
Vacuum deposition is well established, yes?... Never ceases to amaze me how little journalists know and yet their business is writing about things.
It's not journalists, but physicists itself, who are pretending higher achievement, than the reality is. These news are generated at NASA - the PhysOrg just copies them. It's organized PR, the main purpose of which is to shock the laymans.
antialias_physorg
3.7 / 5 (3) Jul 31, 2012
About how many atoms thick of gold would the coating be?

Gold arranges itself in a cubic (face centric) structure with 407 picometers on a side. So about 25 units of such a cubes
(since it's cubic centric that means about 50 2D layers of gold atoms)
stargeezer
4 / 5 (1) Jul 31, 2012
DID SHE TOUCH THE MIRROR IN THE VIDEO ??

talk about scripted


Mrs Goldfinger...