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The James Webb Space Telescope is primarily
an infrared telescope, which means it has
to be kept as cold as possible.
The shape of the sun shield helps it achieve and maintain
those low temperatures.
To find out just how engineers on the ground
are making sure that each layer of the sun shield
is built correctly, we are here at ManTech
in Huntsville, Alabama.
So Jason, this is the sun shield.
What's so unique about its shape?
This 1/10 scale model--
the sun shield from afar looks like a flat piece of material,
but it actually has a doubly curved shape,
which means it's almost a funnel towards the center
of the telescope.
What we're about to see is a full scale layer,
and show you how we measure that shape.
There are five layers.
Is each layer the same?
No, actually each layer is different.
The layers are designed so that we get maximum heat
rejection between each layer, all the way up
to layer five on top.
So that way, layer one will always
be the hottest facing the sun, and layer five
will be the coldest, allowing the telescope
to achieve operating temperature.
So you mean the shape of each layer is different?
Yes, actually it is.
Great.
So we can go check it out now?
Yes, we can.
All right, great.
Over here, we actually have one layer deployed
in a flight-like simulator, and it's tensioned to the loads
that it'll see on orbit.
So like you said, it is not flat.
No, it's not.
You see, it makes a funnel-type shape
towards the center of the telescope.
Where Darryl is standing, the telescope
would be sitting right there in the center, facing us.
So what is he about to do?
He's about to set up a laser scanner.
We use the scanning system to measure the overall shape
of the membrane.
We actually do seven different scans in seven locations.
Each scan, one 360-degree scan, creates about 407 million
points.
We combine those seven scans together
to get enough points to build a solid 3D shape of the membrane
to compare it to our analytical model.
Thanks, Jason, for showing us just what
you guys do to make sure the sun shield is built correctly.
Thanks, Mary, for coming to see it.
After testing here is completed, the layer
will be prepared for integration with the rest of the sun
shield.
Thanks for joining us for this edition of Behind the Webb.