Music
The most prominent and beautiful part of NASA’s ...
James Webb Space Telescope is its gold primary mirror with ...
its smaller, secondary mirror suspended out in front.
The Webb Telescope is a reflecting telescope.
Technically, it’s an anastigmat telescope.
This means that its concave primary mirror captures ...
the light and reflects it to this secondary, ...
, convex mirror, which reflects the light back to the ...
concave rectangular shaped tertiary mirror, ...
then finally to the flat fine steering mirror which sends ...
sends the light through a hole in the center of the ...
the primary mirror to focus at the science instruments ...
behind the primary mirror.
This type of telescope enables a wider field of view ...
and minimizes optical distortions.
The primary and secondary mirror form what is called ...
a Cassegrain telescope similar to the ...
Hubble Space Telescope.
It’s this third powered mirror that makes Webb ...
an anastigmatic telescope.
Music
Webb has the largest primary mirror ever to fly in space.
At 21 feet 3 inches across, or 6 and a half meters, ...
it’s built to see the faintest light coming from ...
from the most distant, luminous objects in the universe.
Its size presents one of the biggest ...
mission’s challenges: the primary mirror is larger ...
than the fairing of the rocket lifting it into space.
So, Webb’s mirror has to be segmented and folded ...
for launch – and that means it has to be unfolded, ...
and focused, in space.
Music
Webb’s mirrors are made of a rare metal called beryllium, ...
because this chemical element is very strong, lightweight ...
and virtually ceases changing shape when it gets really cold.
Music
Starting from beryllium mines in Utah, the mirrors ...
crisscrossed the country.
The beryllium was made into a powder of ...
microscopic spheres, then fused by intense pressure ...
into solid discs that were machined and polished.
Music
Lastly, the mirror segments were coated with a thin layer
of pure gold less than 100 atoms thick to best ...
reflect infrared light.
All of the mirror machining and polishing was done at ...
room temperature, because beryllium changes ...
its shape with temperature and only becomes stable at ...
at very cold temperatures, the mirrors were manufactured ...
to precisely the ‘wrong’ prescription at ...
room temperature so that they have precisely the ...
right shape at operating temperatures.
Thats negative 388 degrees Fahrenheit, or ...
negative 233 degrees Celsius.
That’s colder than the surface of Pluto.
Music
A robot-like system perfectly mounted each mirror ...
onto Webb’s composite backplane structure.
Music
Behind each mirror is an actuator system that can ...
move each mirror segment precisely in ...
every direction, as well as modify each segment’s shape ...
ever so slightly, so that all 18 segments can be aligned ...
to form a single, perfect mirror.
Music
After Webb is deployed, it takes several months for the ...
instruments to cool to their operating temperature.
During this time engineers on the ground will use Webb’s ...
Near Infrared Camera and a process called ...
Wave Front Sensing and Control, to align Webb’s mirrors.
The mirrors will be retuned as needed during the mission ...
to maintain Webb’s perfect vision.
Music
Once Webb launches, and the science team aligns those ...
extraordinary mirrors, a new scientific era will begin.