400 Degrees Below

  • Released Thursday, January 10th, 2013
  • Updated Wednesday, May 3rd, 2023 at 1:52PM

When the James Webb Space Telescope reaches its orbit about 1 million miles from Earth, it will operate at temperatures of almost 400 degrees Fahrenheit below zero. This frigid condition was chosen for a specific purpose: to optimize Webb's infrared sensitivity to see ancient stars and galaxies. Infrared can be thought of like heat radiation; the sun, Earth and stars all give off infrared light. In order to see faint and distant objects, Webb will need to stay very cold and deploy a huge sunshield to prevent stray infrared light from reaching its sensitive mirrors. Precise engineering is required to build multiple instruments that can operate in extreme cold and to construct a large spacecraft capable of unfolding in space. Watch the videos to see how Webb will deploy in space and to see a layer of its protective sunshield being spread out for testing.

The Near Infrared Camera (NIRCam) team bonds the two halves of the NIRCam bench with epoxy.

The Near Infrared Camera (NIRCam) team bonds the two halves of the NIRCam bench with epoxy.

The Mid-Infrared Instrument (MIRI), which will detect light at wavelengths longer than any other Webb instrument, gets a lift in a NASA clean room.

The Mid-Infrared Instrument (MIRI), which will detect light at wavelengths longer than any other Webb instrument, gets a lift in a NASA clean room.

Webb's Fine Guidance Sensor (FGS), which will allow precision pointing to obtain high-quality images, is lifted for inspection.

Webb's Fine Guidance Sensor (FGS), which will allow precision pointing to obtain high-quality images, is lifted for inspection.



Credits

Please give credit for this item to:
NASA's Goddard Space Flight Center
Sunshield photo courtesy of Northrop Grumman
OTE simulator photo courtesy of NASA Goddard/Chris Gunn
NIRCam photo courtesy of Lockheed Martin
MIRI photo courtesy of NASA Goddard
FGS photo courtesy of NASA Goddard
NIRspec photo courtesy of NASA Goddard