Hubble's Successor, The James Webb
Space Telescope: Mission Trailer
• http://www.youtube.com/watch?v=QMRam
EFAQU4
Hubble and Webb:
A tale of two telescopes
Both telescopes share similar goals:
to explore the Universe and improve our understanding of
processes such as the assembly and evolution of galaxies,
star birth, and the formation of planets orbiting other stars
as well as objects in our own Solar System.
This shared purpose is reflected in their common features:
mirrors to collect light from distant stars and galaxies, and
sensors that convert that light into digital images and
spectra.
They both work in the vacuum of outer space, and use radio
signals to transmit their images to Earth.
Both also have solar panels that collect energy to power the
telescope, and pointing control systems that keep the
telescope extremely stable while taking data.
Despite their similarities, these two
telescopes are very different.
• Webb will be optimized for infrared light, unlike
Hubble, which observes in ultraviolet and visible
light and has only limited near-infrared capabilities.
• Webb will also have a much larger primary mirror
that will enable it to collect more light than Hubble.
• Seeing in the infrared is essential for viewing
objects at the edge of the Universe, since the light
from these far-away objects is red-shifted from the
visible into the infrared wavelengths by the
expansion of our Universe.
• Observing far into the infrared also allows Webb to
see deep into the dusty cocoons where stars and
planets form.
• The area of Webb’s mirror is 6 and a quarter
times larger than Hubble’s, which will enable it to
see objects that are fainter and farther away.
• Webb’s size will allow scientists to peer back to
a time when galaxies were just forming!
Webb's sunshield will
keep unwanted infrared
light from the Sun, Moon
and Earth from interfering
with the telescope's
observations, and
prevent radiation from
the telescope's own heatproducing equipment,
such as the solar panels
and computer, from
reaching the science
instruments and optics.
Webb's "bus" is home to the systems that keep
the telescope running: the electronics, attitude
and thermal control, communications, and
propulsion. Webb's bus is one of the
telescope's more standard technologies - a bus
is part of all space
telescopes and
satellites - and
thus requires less
innovation than
many of Webb's
other pieces.
• Webb's primary mirror is made up of 18 individual segments
that fold up inside the rocket that carries it into space.
• Once deployed, they function as a single giant mirror. The
mirror segments are made of beryllium, a metal that is both
extremely strong and light.
• The segments are coated in a layer of gold - approximately 10
wedding rings'
worth to coat the
entire primary
mirror, but spread
ultra-thin - in order
to best reflect
infrared light.
A series of
smaller mirrors
direct the light
from the primary
mirror to the
instruments.
• The Webb Telescope team decided to make the mirror
segments from beryllium, which is both strong and
light. Each segment weighs approximately 20
kilograms (46 pounds).
• The Webb Telescope team also decided to build the
mirror in segments on
a structure which will fold
up, like the leaves of a
drop-leaf table, so that it
can fit into a rocket. The
mirror would then unfold
after launch. Each of the
18 hexagonal-shaped
mirror segments is 1.32
meters (4.3 feet) in
diameter, flat to flat.
Why Beryllium?
• Beryllium is a light metal (atomic symbol:
Be) that has many features that make it
desirable for Webb's primary mirror.
• In particular, beryllium is very strong for its
weight and is good at holding its shape
across a range of temperatures.
• Beryllium is a good conductor
of electricity and heat, and is
not magnetic.
Behind the Webb
http://www.youtube.com/watch?feature=play
er_embedded&v=4gvPl3qWZIM
NIRSpec delivery expected early 2013
FGS is on schedule for delivery during
2012
The cavernous
Thermal Vacuum
Chamber A at
Johnson Space
Center, once
used for the
Apollo program,
is being modified
to test the Webb
Telescope.
Blasting off on top of a rocket, Webb
will take three months to reach its orbit
at the L2 region of space , about 1.5
million kilometers (around 1 million
miles) from the Earth.
The $8.8bn NASA telescope that is 100
times more powerful than Hubble and will
let us look back into the dawn of time
It’s one of the most technologically advanced devices ever built and will give
cosmologists incredible insights into the origins of the universe.
Nasa's James Webb Telescope, if it’s a success, will herald a new era in the
understanding of the
universe, because it will
be able to look further back
in time, and with more clarity,
than any telescope that exists
today.
Nasa boasts that the
telescope is 100 times more
powerful that the Hubble, a
device that has already given
star-gazers thousands of
stunning images of the
cosmos.
21 February 2012
• But the project has a dark side - it is costing the U.S.
space agency so much money that it is acting like a
financial black hole, sucking funds away from other
projects and threatening their future.
• The telescope began as a $500million project in the late
1990s, but that cost has now ballooned to over
$8.8billion.
• Last year Congress tried to permanently halt the project.
It’s all systems go at the moment, but it’s such a drain on
Nasa’s budget that the agency may only be able to afford
one big science mission per decade from now on, with
some key projects killed off.
• For example, House Science Committee staff warn that
a mission to bring Martian soil back to Earth may now be
too expensive to carry out
• It will launch in 2018 and operate nearly a million miles
from Earth
EDUCATION
http://www.jwst.nasa.gov/teachers.html
http://zeus.as.arizona.edu/~dmccarthy/GSU
SA/Activities.htm