Europe’s RLV C5 Rocket Concept: A More Efficient Rival to SpaceX Starship

The German Aerospace Center (DLR) published a study proposing an alternative heavy-lift aerospace architecture named the RLV C5, designed to achieve higher structural efficiency than SpaceX’s Starship system. According to an independent evaluation by researchers at the German Aerospace Center (DLR) published in May 2025, the new European concept targets a payload mass fraction of up to 74 percent for low Earth orbit operations.

Evaluating SpaceX Starship Performance Through Telemetry Data

To build their performance models, researchers from the German Aerospace Center (DLR) studied publicly available data by extracting telemetry from public video broadcasts of early SpaceX flight tests. According to the German Aerospace Center (DLR), a text recognition algorithm logged second-by-second flight data from the first four integrated flight tests. That research validated that the current fully reusable version of Starship delivers approximately 59 tonnes to low Earth orbit. In addition, projections derived from German Aerospace Center (DLR) simulations indicate that SpaceX’s upcoming iteration of Starship—equipped with Raptor 3 engines and enlarged propellant reservoirs—will reach a reusable lift capacity of roughly 115 tonnes, which increases to 188 tonnes when operating expendably.

Structural Efficiency and Design Trade-Offs of the RLV C5

In contrast to SpaceX’s Starship—which depends on structural strengthening, heavy thermal protection tiles, and reserved landing fuel to achieve total vertical touchdown—the European RLV C5 design follows an alternative architectural path. Research conducted by the German Aerospace Center (DLR) outlines that the RLV C5 integrates an expendable upper portion with a reusable winged booster originating from the long-standing SpaceLiner initiative. Liquid hydrogen and liquid oxygen power the vehicle, offering a higher specific impulse and greater propellant efficiency than the oxygen and methane combination utilized by SpaceX’s Raptor motors. Because the RLV C5 booster glides back into the atmosphere and avoids carrying extra fuel for a powered vertical landing, it devotes about 74 percent of its mass to payload, compared to Starship’s approximately 40 percent.

Propulsion and Recovery Systems Compared

The operational strategies of the two launch systems diverge significantly upon booster return. SpaceX utilizes giant mechanical launch tower arms, known as Mechazilla, to catch returning Super Heavy boosters after they slow down by firing their Raptor engines. Instead of a powered vertical touchdown, the RLV C5 booster relies on an aerial mid-air retrieval by a large subsonic aircraft after gliding through the atmosphere, drawing upon a booster architecture that has been under development within the SpaceLiner project since 2005. While Starship targets full reusability to minimize hardware waste over thousands of flights, the German Aerospace Center (DLR) researchers emphasize that the RLV C5 maximizes immediate structural efficiency through partial reuse, according to the study. Both systems represent fundamentally different engineering philosophies for super-heavy orbital lift capacity.