Once we were mounted on the gondola, we started filling the cryostat with lots of liquid Helium (LHe). The first few LHe fills are exciting; the relatively warm (precooled to liquid nitrogen temperatures of 77 degrees above absolute zero) guts of the cryostat cause a lot of the LHe to rapidly boil off, so there’s lots of cold He gas, freezing piping, and other excitement that requires a watchful eye.