This piece of hardware is called Core-2 and is a test model of the “observatory core” — the part of the James Webb Space Telescope where telescope meets spacecraft. Most of the heat flow through the observatory happens in this core region — and so this region must undergo extensive thermal testing.
Here, technician Andrew Peterson installs thermal blankets to the underside of the James Webb Space Telescope test model.
The Webb telescope is being assembled in a Class 10,000 cleanroom at NASA’s Goddard Space Flight Center in Greenbelt, Md.
Source: NASA