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Observatory: The Optical Telescope Element (OTE)

The Optical Telescope Element (OTE) is the eye of the James Webb Space Telescope Observatory. The OTE gathers the light coming from space and provides it to the science instruments.

NASA's James Webb Space Telescope Primary Mirror Fully Assembled
The OTIS out of cryovac chamber at NASA Johnson. The OTIS is an acronym that includes the OTE plus the Integrated Science Instrument (ISIM) package - essentially the optics and science instruments. Credit: NASA/Chris Gunn

The OTE consists of the mirrors as well as structures and subsystems that support the optics.

The OTE is made up of:

1) 6.5 meter diameter primary mirror made of 18 hexagonal segments

2) Round 0.74 meter Secondary mirror

3) Tertiary mirror and Fine Steering Mirror, both of which are contained in the Aft Optics Subsystem.

4) Telescope structure (which includes the primary mirror backplane assembly, the main backplane support fixture (BSF), the secondary mirror support structure, and the deployable tower array) The BSF will house the instrument module.

5) Thermal Management Subsystem

7) Aft Deployable ISIM Radiator (ADIR)

9) Wavefront sensing and control

OTE diagram