Yesterday’s complex hot fire test of an engine technology demonstrator, was the first in a series of planned tests guiding Europe’s next-generation upper-stage rocket engine design.

By the end of the year, the Expander-cycle Technology Integrated Demonstrator, or ETID, based at the DLR German Aerospace Center test facility in Lampoldshausen, will be ignited 20 times with each firing lasting up to 120 seconds on a test stand that provides a near-vacuum environment similar to space.

“This first test was important for us to confirm the startup of this innovative expander-cycle engine design,” commented ESA’s lead engineer Kate Underhill, “where the liquid hydrogen propellant is ‘expanded’ through cooling channels in the hardware before combustion. Going from liquid hydrogen temperatures to full combustion in just over a second means timing is everything!”

Engineers will use the results from the test campaign to determine the hardware characteristics, including a precise thrust measurement to determine its “specific impulse” – indicating the exact performance of the engine design.

Following four rounds of tests the configuration will be changed for further tests with different igniters and different hardware designs and materials. The aim is to bring them all to a technology readiness high enough to transfer them at minimum cost and risk to any subsequent development project for flight.