The Throttleable Liquid Propulsion Demonstrator (TLPD) is a Łukasiewicz Research Network – Institute of Aviation rocket engine demonstrator that will be ideal for use as part of upper stages on small rockets and could be used on spacecraft, kick-stages or exploration missions. The engine can vary its thrust down to 10% and up to 110% of its ideal operating conditions, making it a good candidate for use on landing on other planets. It is restartable and runs on non-toxic easily-storable propellants.

The first test-firing phase last year proved the engine’s operations at different thrust levels in steady states, but kept the engine running at set power levels from startup to the end of each firing. These tests validated the high-tech valves that regulate the flow of the propellants to the engine.

The team used a passively-cooled combustion chamber during the first phase of testing since the short test duration didn’t require active cooling. As the tests proceeded the team saw that the engine heated up less than the hottest temperatures predicted, so they decided to conduct a first batch of throttling tests ahead of schedule. These tests saw the engineers change the thrust – or power of the engine – while still firing. The results continued to be very promising.