BUILDING THE BIGGEST EYE IN SPACE
Webb’s range
of vision
Webb is designed to study
the infrared sky, for the
first time at such high
resolution.
Constructing a successor to the Hubble Space Telescope has been an epic undertaking involving more than 1000 people
in 17 countries over 2 decades. As that effort reaches its climax, the telescope components face a complex series of tests
to ensure that the telescope deploys—and works—perfectly.
July
December
April
May
July–Sept.
February
August–Nov.
December
May–Sept. April
Structure to hold Webb’s
instrument module
arrives at Goddard
Space Flight Center.
Main mirror
segments finish
testing at Marshall
Space Flight Center.
Center section of
main mirror's
backplane support
structure finished.
First instrument
arrives at Goddard
from Europe.
Remaining three
instruments
delivered
to Goddard.
Main mirror
backplane wing
structures
complete.
First cryo-vacuum
test of instrument
module.
Main mirror
segments
delivered to
Goddard.
Second cryovacuum test
of instrument
module.
2011
2012
2013
Telescope
deployment
tower
completed.
2014
10-12
Visible
light
10-6
10-9
Gamma rays
X-rays
Ultraviolet
10-3
Infrared
Microwaves
Webb
Hubble
Kepler
Webb’s instruments
were tested three times
inside a pressure vessel
at Goddard to simulate
the cold and vacuum of
space. While inside,
various forms of light
were shone through the
instruments to test
their operating modes.
The combined telescope and
instruments will be tested in
2017 inside the giant
Chamber A at Johnson Space
Center. Suspended from the
ceiling to reduce vibration, the
telescope will look up at an
artificial universe.
Space environment
simulator
October–January
April
Feb.–May
May
Oct.–May
August
October
Third cryo-vacuum test
of instrument module
and mirror segments
fitted to backplane.
Telescope and
instrument
module joined.
Telescope/
instruments in
cryo-vacuum
test in Johnson’s
Chamber A.
Telescope/
instruments
shipped to
California.
Telescope/
instruments
combined with
bus/sunshield
and tested.
Webb
transferred by
ship to French
Guiana.
Launch on
Ariane
5 from ESA
spaceport.
2016
2017
2018
Primary mirror
Instrument module
Telescope simulator
Secondary
mirror
Vibration
isolation
system
Herschel
Vibration and
acoustic testing
of instrument
module.
Light
Telescope test
Spitzer
Radio
June–July
Testing and technology
Instrument module test
Wavelength 1 m
6.5 meters wide and composed of
18 hexagonal segments made of
beryllium and coated with gold to reflect
infrared light. Behind each mirror
segment are actuators to accurately
control its position and curvature.
Deployment
of secondary
mirror
Actuators
Telescope
primary
mirror
Vibration isolation
supports
Mirror
backside
Position
Curvature
Deployment in space
Like a butterfly emerging from its cocoon,
Webb will unfurl its components step by step
on its way to its final orbit.
Sunshield
pallet
Cold side
1
30 min
10,000 km
Webb separates
from launch
vehicle.
Earth
Antenna
3
2
34 min
11,000 km
Solar array
deploys.
4
3 days
480,000 km
Sunshield pallets
deploy.
6 days
680,000 km
Sunshield extended
and tensioned.
Moon 384,800 km
Spacecraft
bus
–233°C
Solar
radiation
5
1.8-m
person
to scale
11–14 days
1,000,000 km
After the secondary mirror swings into place
on its supports, the wings of the main mirror
rotate into position and mirror phasing begins.
Hot side
85°C
Thermal protection
The heat of the sun would
swamp faint infrared
signals from deep space
so Webb’s sunshield
reduces solar heat to less
than one-millionth its
normal value.
Day 29
Final orbit
of telescope.
1,500,000 km
CREDITS: (DATA) NASA; (ILLUSTRATIONS) SOHAIL AL JAMEA;
.
A. CUADRA/SCIENCE
Sunshield