Prometheus tests add methane-engine capability to Europe’s P5 test bench

A manufacturing change reaches the hot-fire stage

ESA says the tested engine incorporated a combustion chamber produced using cold gas spray, an additive manufacturing technique. The announcement presents the tests as validation of both the upgraded bench and the new production approach. It gives no measured unit-price saving or series-production rate for the chamber.

Our assessment is that the useful manufacturing milestone is the connection between a new way of producing a component and an operating test. A lower-cost production objective becomes more assessable when hardware made by that process can be tested repeatedly. Cost and production claims would still need their own manufacturing evidence.

The new capability belongs to a sequence of tests

The earlier Prometheus campaign in Vernon, France, already demonstrated four consecutive ignitions on 20 June 2025, according to ESA’s July 2025 account. The October 2026 campaign should therefore be read for its specific additions: the P5 methane upgrade, repeated operation there and the newly manufactured chamber.

ESA also reports repeated re-ignition without a high-pressure starter system in the new campaign. DLR emphasises stable operating points and the ability to investigate changes in thrust. These are defined ground-test results and capabilities; the reports do not supply a completed flight-reuse record.

Facilities are part of the route to reusable launch systems

DLR describes P5’s measurement systems recording thrust, propellant flow, pressure ratios and temperatures. Its expanded capability allows researchers to study the interaction between operating phases. ESA says the bench can also be adapted back to oxygen-and-hydrogen operation, preserving a role in testing hydrogen engines.

For European equipment and manufacturing teams, this illustrates why test infrastructure belongs in the industrial plan alongside components and final launch vehicles. A facility that can investigate repeated sequences provides a place to compare design changes under controlled conditions. Neither agency announces a new supplier competition in these reports.

The next campaign described by ESA concerns an improved Prometheus Mark 2, with initial testing planned at ArianeGroup’s Vernon centre. Following the results of that campaign will help show how the production and operating changes progress through successive engine versions. The published next step is further testing, with no new launch date specified.