Stellar Alpina reports completing 150 rocket-engine hotfires across 23 configurations, exceeding its target of 100 tests over the summer. The Duebendorf propulsion company is developing rotating detonation rocket engines; the campaign follows the eight initial hotfires covered in its earlier funding announcement.
The team deliberately pushed combustion chambers to failure to investigate design limits and collected measurements to guide subsequent iterations. It reports turnaround times as short as 30 minutes between some tests and shared footage of the campaign. These are ground-development tests, not flight qualification or an orbital demonstration.