The making of NASA’s most powerful space telescope
The making of NASA’s most powerful space telescope
2016-12-05
say hello to NASA's James Webb Space
Telescope well part of it anyway but
this is perhaps the most important part
a huge gold-coated mirror that spans
over 21 feet the actual telescope
portion of this Space Telescope the
optics or eyes if you will
it's what the telescope will use to
gather light from the early universe
allowing us to see deeper into space and
further back in time than we've ever
seen before so far in fact we'll be able
to see the stars and galaxies that form
just after the Big Bang that's because
when it launches the James Webb will be
the most powerful Space Telescope ever
created compare that to the Hubble Space
Telescope which has been taking
spectacular images from orbit for the
past 20 plus years well this new
telescope is a whole lot bigger its
mirror has seven times the collecting
area of Hubble's mirror and James Webb
is going to live much farther out in
space 1 million miles from Earth in fact
it's from this deep outpost that James
Webb will see the universe when it was
just a newborn light from the oldest
most distant objects takes a while to
reach us and the universe is thought to
be 13.7 billion years old so the light
from the first forming galaxies and
stars has crossed over 13 billion light
years of space to get here so the
farther out we look the further back in
time we can see but James Webb won't be
looking for visible light from these
objects instead it'll be looking in the
infrared it's a type of light we can't
see but can feel as he it all has to do
with our ever expanding universe the
earliest objects are moving away from us
relatively quickly and this movement
extends the wavelengths of their light
toward the red end of the spectrum it's
a concept known as redshift and the
farthest galaxies have been red shifted
into the infrared and this light is
super hard to pick up you see everything
that's warm emits infrared light so you
can't have a telescope like this one on
earth you'll just pick up the infrared
light in our atmosphere and from our
planet even the telescope itself emits
too much heat that's why James Webb is
going to
super far out in space where it can be
kept at a frigid temperature of less
than 50 degrees above absolute zero
that's minus 370 degrees Fahrenheit in
order to pick up this infrared light
that's where James Webb's Mirror comes
in it's made up of 18 hexagons of
beryllium all of which are coated in a
thin layer of gold that's just one
thousandth the thickness of a human hair
the gold is what makes it easier to see
in the infrared those mirrors will then
reflect light onto a secondary mirror
extended out in front of the telescope
that mirror will funnel light into the
telescopes instruments on the backside
of the mirror and it's these instruments
that will give us the juicy details
about the early days of the universe as
well as see things sharper than any
telescope has before if you were a
bumblebee I'll bring out at the distance
of the moon we would be able to see you
both by your reflected sunlight and by
the thermal radiation the heat that you
admit but there's still a long journey
ahead before that can happen
and NASA's already been working on the
James Webb for two decades now its
development has been hampered by delays
and budget problems the telescope was
expected to cost somewhere between 1 and
3.5 billion dollars with a launch
somewhere between 2007 and 2011 but its
budget continued to grow by billions and
it's launch date kept getting delayed
that caused NASA to do a replan of the
entire project in 2011
now the James Webb mission is expected
to cost 8.8 billion dollars with a
projected launch in October 2018 nASA
says the telescope is finally on budget
and on schedule for that launch but
there's still a lot of testing that
needs to be done the telescope portion
of James Webb has to go through
vibrational and acoustic testing at
NASA's Goddard Space Flight Center to
see if it can handle its launch into
space it'll then head to Johnson Space
Center in Houston to go through
cryogenic testing to see if it can
handle those super freezing cold
temperatures and after that it's off to
California where the telescope will meet
up with its Sun shield five layers of a
material called Kapton that are roughly
the size of a tennis court
Cheil will help protect James Webb from
too much heating by the Sun after some
more testing there the telescope will be
ready to fly it will be loaded on a ship
bound for French Guiana in South America
where the telescope is set to launch on
top of an Ariane 5 rocket but once James
Webb launches the anxiety is far from
over the telescope is so big that has to
be folded up during launch and when it
gets to space it has perhaps the most
complicated deployment process a
satellite has ever had to pull off
here's what that process looks like
we've sped it up for you a little bit if
one of these things goes wrong it could
spell bad news for the rest of the
mission and once James Webb is out there
that's it we can't really visit the
spacecraft when Hubble needed upgrading
astronauts could just get into low Earth
orbit to fix it but James Webb will be
so far out into space that taking a trip
to the telescope is basically out of the
question if this actually works though
we're going to see a part of our
universe we've never seen before and
it's not just the earliest stars we're
going to see we'll also be able to see
even more planets that orbit around
distant stars so not only will we find
out more about how our universe evolved
but maybe even get closer to answering
if we're alone out here - yeah I don't
know
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