[MUSIC PLAYING]
The mirrors on the James Webb Space Telescope
have components attached to the back of each of them.
What exactly are these?
And what do they do?
Well, we're here at Ball Aerospace in Boulder,
Colorado to find out.
So, Brad, what's going on over here now?
Well, we are bonding items to the back of the mirror.
And that is to distribute the loads during launch
as well as to distribute the loads during the mission.
And this is a precursor to more items being
attached to the mirror, right?
Yeah, that's correct.
The next step is when we attach the hexapod assembly
and the radius of curvature subsystem
onto the back of the mirror.
Sounds like a mouthful.
I think it'd be better understood
if we actually see one.
Sure.
The hexapod assembly has the six rigid-body actuators.
Its job is to manipulate the mirror
in six degrees of motion.
The radius of curvature subsystem
is one of the six struts.
And there is an actuator that goes
to the center of the mirror.
It can, very precisely, change the radius of curvature
of the primary mirror.
Because the mirror consists of 18 primary mirror segment
assemblies, those 18 primary mirror segment assemblies
must be adjusted while on orbit to mimic
a perfect primary mirror.
So, Brad, can we take a closer look at these actuators?
Talk to Jake Lewis.
And he will bring you up to speed with the actuators.
Jake?
Yes?
Yeah.
Brad told me that you are the man with the actuators.
Absolutely.
Can we take a closer look at them?
Sure.
So here, we have the hexapod.
And we're aligning the actuators onto it.
And our precision alignment fixture
allows us to build each hexapod identically.
Now that they've positioned the actuators on here,
they've got to verify that it's in intolerance.
So they're measuring it to make sure
that it's in the exact position that it needs to be do.
You have different actuators for the different mirrors?
Or are they all the same?
No.
One of the things that we've done is that all of the mirrors
have exactly the same actuators on them.
Secondary?
Tertiary?
All those?
Just the secondary and primary mirrors have actuators.
The tertiary doesn't have any actuators on it.
It stays fixed.
But the only difference between the primary and secondary
mirror hexapods is the size of the frame.
The actuator assembly all remains identical.
And that's a cost savings and a great simplification for us.
Well, thanks for giving us a sense of what actuators
are on the James Webb Space Telescope
and the hexapod assembly.
You're welcome.
As you can see, these actuators with the hexapod assembly
make these mirrors on the James Webb Space Telescope
much more complex than the ones that, say,
you might have in your bathroom.
But these mirrors have a job to do
to look at a universe billions of light years away.
Thanks for joining us for another edition
of Behind the Web.