A US-based propulsion company, Venus Aerospace, said Wednesday it had completed a short flight test of its rotating detonation rocket engine at Spaceport America in New Mexico. The company's chief executive and co-founder, Sassie Duggleby, characterized the flight as "historic." It is believed to be the first US-based flight test of an idea that has been discussed academically for decades, a rotating detonation rocket engine. The concept has previously been tested in a handful of other countries...