ArianeGroup Restarts Themis Test Campaign With Cryogenic Rehearsal in Sweden
ArianeGroup has completed a wet dress rehearsal of its Themis reusable booster demonstrator at the Esrange Space Centre in Sweden, the first substantive update on the vehicle's test campaign in more than ten months. The rehearsal, conducted on 23 July, moves the program toward its first low-altitude hop test. The test was carried out by teams from ArianeGroup and SSC Space, the commercial entity that manages the Esrange Space Centre. ArianeGroup announced the milestone on 30 July, a full week a
OST Staff · July 30, 2026
ArianeGroup has completed a wet dress rehearsal of its Themis reusable booster demonstrator at the Esrange Space Centre in Sweden, the first substantive update on the vehicle's test campaign in more than ten months. The rehearsal, conducted on 23 July, moves the program toward its first low-altitude hop test.
The test was carried out by teams from ArianeGroup and SSC Space, the commercial entity that manages the Esrange Space Centre. ArianeGroup announced the milestone on 30 July, a full week after it took place. It marks the most significant publicly announced step in the Themis campaign since September 2025, when the T1H demonstrator was erected on its four landing legs at Esrange, marking the start of combined testing.
The long public silence had followed comments in January 2026, when the then director of ESA's space transportation programme explained that Kiruna, where Esrange is located, was under snow and that teams were waiting for spring.
During the rehearsal, the 28-metre-tall demonstrator underwent a simulated pre-flight sequence under cryogenic conditions. The simulated operations were conducted over one day and included preparations for both the vehicle and the launch pad, the countdown itself, and procedures to make the site safe following a simulated flight and recovery.
The test did not use the liquid oxygen and liquid methane that will be used during powered testing. Instead, liquid nitrogen was circulated through the vehicle's cryogenic tanks and lines. The liquid nitrogen reproduced temperatures and pressures representative of flight operations, with temperatures falling as low as minus 200 degrees Celsius.
ArianeGroup said the rehearsal provided data that will support the next stages of the campaign as Themis moves toward its first low-altitude hop test.
It is not yet clear when the next milestone in the test campaign will take place. ArianeGroup said the teams are now working to define the window for the next test.