Slide 1
Webb’s own warmth can interfere with faint infrared signals
Warm telescope components emit infrared radiation that can interfere with measurements of faint infrared signals.
More to Read
Warm objects emit infrared radiation, including parts of an observatory. A telescope designed to study faint infrared signals must therefore manage its own heat. Webb's sunshield helps separate a warmer Sun-facing side from the colder side used for observation.
Slide 2
Separated shield layers limit heat reaching the telescope
Webb's separated sunshield layers limit heat transfer toward the telescope while allowing heat to escape into space.
More to Read
The sunshield uses multiple separated layers to reduce heat reaching the telescope side. Its shape and arrangement are functional parts of the observatory. The layers limit the transfer of incoming heat toward the instruments while allowing heat to escape into space, supporting the temperature difference between the two sides.
Slide 3
Its orbit helps keep the heat sources on the shielded side
Webb orbits around the Sun–Earth L2 region, beyond Earth away from the Sun. This helps keep the Sun, Earth and Moon on its shielded side.
More to Read
L2 is a region about 1.5 million kilometres beyond Earth, away from the Sun. Webb orbits around that region, which helps keep the Sun, Earth and Moon toward its shielded side. Webb is neither motionless at L2 nor permanently concealed in Earth's shadow; it carries the shade its thermal design requires.
Slide 4
Less thermal emission makes faint signals easier to detect
Reducing thermal emission helps Webb detect faint infrared signals. The sunshield supports passive cooling across much of the observatory.
More to Read
Controlling thermal emission helps instruments measure faint infrared signals. The sunshield enables passive cooling for much of the observatory, while some instrument cooling also requires active equipment. One dramatic shield is therefore part of a larger thermal system, not the only cooling mechanism.
Slide 5
A detector also needs the right surroundings
A sensitive detector depends on the environment around it as well as its ability to collect light.
More to Read
A sensitive detector cannot do its job independently of its surroundings. Webb's orbit and thermal engineering create conditions in which useful measurements become possible. The design lesson is that controlling an instrument's environment can be as important as the instrument's ability to collect light.
Sources
- Webb's Sunshield
NASA Science
- Webb FAQs
NASA Science