ArianeGroup Completes Themis Cryogenic Rehearsal at -200C, Advancing 28-Meter Booster Toward Hop Test
Updated
Updated · European Spaceflight · Jul 30
ArianeGroup Completes Themis Cryogenic Rehearsal at -200C, Advancing 28-Meter Booster Toward Hop Test
3 articles · Updated · European Spaceflight · Jul 30
Summary
ArianeGroup said the 28-meter Themis demonstrator completed a wet dress rehearsal at Sweden’s Esrange Space Centre on July 23, the first substantive public test-campaign update in more than 10 months.
The one-day exercise simulated pre-flight operations under cryogenic conditions, covering vehicle and pad preparations, countdown procedures, and post-flight site safing.
Liquid nitrogen—not the liquid oxygen and methane planned for powered tests—was run through tanks and lines to reproduce flight-like pressures and temperatures down to -200C.
The rehearsal is the biggest announced milestone since September 2025, when the T1H demonstrator was erected on its four landing legs at Esrange for combined testing.
ArianeGroup said data from the test will support the next campaign stages, but it has not set a date for the first low-altitude hop test and is still defining the next test window.