Pointing and Positioning Mechanisms

RUAG Space is offering Pointing and Positioning Mechanisms as well as Electric Propulsion Pointing....

Pointing Mechanisms

Coarse Pointing Mechanisms

The Coarse Pointing Assembly consists of three main assemblies:

  • Support Assembly
  • Azimuth Scan Unit (ASU)
  • Elevation Scan Unit (ESU)

The Coarse Pointing Assembly is a part of the Optical Head and offers a compact low mass pointing and tracking function in two axes. This is achieved by employing a gimballed mirror configuration. This configuration can be adapted for any further commercial application. The follow-up missions are Alphabus and Meteosat Third Generation (MTG).

Fine Pointing Mechanims

  • 2-axis tip-tilt mirror
  • Angular range: + / - 10 mrads
  • Signal-Bandwith: 1 kHz (~ 3 dB)

Antenna Pointing Mechanism

The Antenna Pointing Mechanism (APM) is a dual drive (azimuth over elevation) unit. The main functions of the Antenna Pointing Mechanism (APM) are to provide accurate and stable pointing of the reflector and elevation axes and to route the RF signals between the antenna and the spacecraft.

  • Rotation range azimuth stage: 237°
  • Rotation range elevation stage: 340°
  • Pointing speed: up to 2.5°/s
  • Pointing accuracy: better than 0.1°
  • Power consumption: < 6 W/stage

Single Axis Articulation

The high precision single axis articulation has been developed for SILEX, an optical data transfer interlink between satellites. The mechanism associates a ball-bearing pair, an optical encoder, a torque motor and a cable wrap for the electrical connections between the rotating and fixed parts.

A special attention on the torque performances (low torque, low noise, reproducibility) has been obtained. The hardware execution is compliant with the very high performance and quality level required by space applications.

  • Angular range: 200°
  • Number of pair connections: 95
  • Number of RF connections: 2
  • Maximum acceleration: > 1°/s2
  • Maximum rotation speed: > 5°/s
  • Life: > 300’000 cycles
  • Torque constant: 0.12 Nm/rad
  • Hysteresis: 0.4 Nm
  • Mass (with full articulation): 9 kg

Electric Propulsion Pointing

RUAG Space delivers qualified Pointing Mechanisms for electric propulsion thrusters, which are increasingly used on commercial satellite platforms and scientific spacecraft due to their advantages in fuel mass efficiency.


The Pointing Mechanism supports the electric propulsion thrusters in their nominal position during launch, by means of a dedicated hold down and release mechanism and reduces the mechanical loads on the thrusters via dedicated damper elements.

Upon its release, the thrusters can be tilted around two axes. This motion is facilitated by two actuators, which drive the platform either via a strut-linkage around a spherical joint or a cross gimbal type arrangement.


RUAG Space Electric Propulsion Mechanisms are used for:

  • North South station keeping
  • Orbit topping
  • Momentum dumping
  • East West station keeping
  • Orbit raising
  • De-orbiting
  • Interplanetary propulsion


RUAG Space can deliver Pointing Mechanisms for any thruster available on the market, for the following thrusters the mechanisms are qualified:

  • Fakel SPT 100 (Plasma)
  • Fakel STP 140 (Plasma)
  • Snecma PPS 1350 (Plasma)
  • Snecma PPS 5000 (Plasma)
  • Airbus ROS 2000 (Plasma)
  • QinetiQ T6 (Ion)
  • MMS/QinetiQ EIT (Ion)
  • Airbus RIT (Ion)

Interested? For more information please contact:
Niklas Boman, Director Marketing & Sales Spacecraft
T: +41 79 77 07 107