Low Energy Response on Major Space Missions Was very good at 1/4-keV on HEAO-I Einstein ROSAT Since then much poorer due to Front side CCD electrode structure UV/Optical/IR blocking filters Mirror thermal shields Much science lost: 10 6 K gas is ubiquitous — cooling minimum.

38 mm clear diameter 350 µm pitch mesh 5 mm pitch backing mesh 95% open Ion-implanted deicing heater All Si — light and stiff

20 nm Al/50 nm polyimide ~1 p.s.i. breaking

New XQC Sounding Rocket Flight 6 x 6 4mm 2 pixels

Still not as good as you’d like — Microcalorimeters viewing 300 K over large solid angle need 10 –9 attenuation from ~2 µm to 2 cm. Requires 100 nm of Al if divided into 5 separate tilted filters. Microcalorimeters would be badly-needed improvement in detectors for vacuum UV through EUV. Best solution is waveguide-below-cutoff filter. Need someone who understands E&M and surface plasmons!