PanelSat® DTU

© PanelSat GmbH

Double Thruster Units are integrated propulsion modules consisting of two oppositely directed thruster nozzles and their associated fuel tanks, mounted inside structural support pipes. These pipes carry the satellite body during launch and become active thruster conduits once in orbit. Each DTU is pairwise attached to opposite points on the outer rim of the satellite structure.

Two such DTUs always work as a coordinated pair. This configuration forms a balanced propulsion system.

Unlike conventional spacecraft, which typically need to rotate their entire body in order to perform a counter-thrust maneuver, PanelSat® can instantly apply an opposing force without changing its orientation. This is achieved by simply activating the reverse-facing thruster within the same DTU. The thrust architecture directly supports the ability to reposition or reorient a satellite rapidly — a capability increasingly seen as critical for achieving and maintaining space superiority. The architecture enables:

• immediate reversal or deceleration of thrust-driven movement,
• fuel-efficient braking or counter-rotation without prior reorientation,
• more precise maneuvering and stabilization,
• the ability to perform orbital adjustments or controlled deorbit maneuvers even in the absence of external torque systems.

This concept represents a fundamental departure from the way conventional spacecraft handle thrust vectoring. For example:

• In April 2025, the International Space Station (ISS) performed a full 180° rotation to enable retrograde docking of the Russian Soyuz MS-27 spacecraft. The station had to reorient its docking port because counter-thrust without rotation was not possible.
• During early NASA Mercury missions, the capsule had to rotate completely before firing its retrorockets for re-entry, since the re-entry thrusters were fixed in only one direction.

By contrast, PanelSat® avoids such complex and time-consuming rotations, allowing more responsive and efficient orbital operations.

Patent origin

The underlying DTU concept was originally described in the German patent DE 10234902 A1, filed on 26 July 2002 and published on 12 February 2004 by Frank Ellinghaus. The patent, titled:
"Thruster-Solar-Segler, Segment-Montage-System, Photonen-Segler, Rotations-Schleuder experimentelles Raumfahrzeug",
explicitly introduced the idea of opposite-facing thruster pairs within a single structural unit. Although the patent has since expired, it documents the original invention and establishes early authorship of a propulsion architecture now realized in the PanelSat® platform.