noiselaunch2026-09-29

ArianeGroup completes second Themis wet dress rehearsal

ArianeGroup and SSC Space ran a second cryogenic countdown rehearsal of Europe's Themis reusable-rocket demonstrator at Esrange.

// sources · 2 attached

what happened

ArianeGroup and SSC Space completed a second wet dress rehearsal of ESA's Themis reusable-stage demonstrator at Esrange in Sweden on Sept. 29, filling the vehicle with liquid nitrogen cooled to about -200°C in place of propellant, per SSC Space and European Spaceflight. The teams achieved new milestones repeating the "synchronized sequence," the countdown's final automated phase, and tested the post-flight sequence using a fleet of robots designed to secure, connect to and safely drain the vehicle after landing, per SSC Space. ESA said teams are now defining a window for the next test: at least one more full wet dress rehearsal using liquid oxygen and liquid methane is planned before a hot-fire test of the demonstrator's Prometheus engine, itself a precursor to Themis's first hop to roughly 100 meters altitude, per European Spaceflight.

why it matters

Themis is Europe's first full-scale reusable-stage demonstrator, ArianeGroup's answer to SpaceX's and Rocket Lab's reusable boosters; each successive rehearsal milestone narrows the gap to a hop test that would give European launch services their first real reusability data point, relevant to Ariane's successor and to any European operator weighing reusable versus expendable vehicles for the next decade.