Validation testing continues for ESA's all-new Ariane 6 launch vehicle, with firing of its two upper stage engines to simulate the way they will have to operate together during a flight.
The test of the full upper stage—including the new Vinci engine and a smaller Auxiliary Power Unit (APU)—took place on a purpose-built test bench at German Aerospace Center DLR's engine test center in Lampoldshausen, Germany.
Vinci, the upper stage engine of Ariane 6 fed by liquid hydrogen and oxygen, can be stopped and restarted multiple times—to place satellites into different orbits and then de-orbit the upper stage, so it is not left behind as hazardous debris in space. The APU makes it possible for Vinci to restart in space, by maintaining adequate pressure in the fuel tanks and preventing bubbles in the fuel lines. The APU uses small amounts of liquid hydrogen and oxygen from the main tanks—replacing a system which relied on large quantities of tanked helium.
The test was a success, and the two engines operated as expected. The Vinci engine fired for a total of 10 minutes, and the APU fired for several seconds to demonstrate its ability to restart the main engine.
A last hot-fire test is scheduled before final qualification of the Ariane 6 upper stage, with the aim of testing its operation for different types of missions, as well as in degraded conditions.
"This test is a major milestone for the Ariane 6 program," said Toni Tolker-Nielsen, ESA Director of Space Transportation. "It demonstrates that the upper stage is ready to meet the demanding requirements of our customers. We are making good progress on the Ariane 6 program, and I am confident that it will be a success."
The tests at Lampoldshausen are being run in parallel with tests on the launch pad at Europe's Spaceport in French Guiana. There, Ariane 6's lower core stage engine—Vulcain 2.1, adapted from Ariane 5's Vulcain 2—is being test-fired to simulate an actual launch. Launch pad tests feature a test model of the 60-m tall Ariane 6. This rocket is not intended to fly but is essentially identical to a flight model apart from its solid fuel boosters, which are inert mock-ups. These tests will ensure that the rocket and ground infrastructure work together as a complete system.
The Ariane 6 is scheduled to make its maiden flight in 2023. It is a more affordable and flexible launch vehicle than the Ariane 5, and it is expected to play a major role in Europe's space ambitions for the next decade and beyond.