In this timelapse, the SPHEREx telescope and focal plane arrays, mounted on top of three V-groove coolers, are installed in a thermal vacuum chamber provided by KASI that cools the hardware to its operating temperature in space. The process requires a series of lifts and a translation cart built by KASI, employing a team of over 20 people over 2 weeks.  Once the installation is finished, pumping out the chamber and cooling down takes a couple more weeks.  The team uses the chamber to check the optical focus by illuminating the telescope with laboratory sources through a custom-made sapphire vacuum window. Courtesy NASA/JPL-Caltech