“Despite the commonly accepted truth in Hard Science Fiction, spacecraft are able to evade detection in space in many circumstances. The Hydrogen Steamer was a design that used liquid hydrogen evaporative cooling to keep a non-reflective surface practically invisible.
However, it was vulnerable to RADAR and had extremely poor manoeuverability, as it was meant to demonstrate how long it could stay cool. This time, we will design a more advanced, functional and performant stealth spacecraft.
The rest is at toughSF: https://toughsf.blogspot.com/2018/04/permanent-and-perfect-stealth-in-space.html