Positioning Mechanisms


MSL Drive Mechanism

The MSL (Material Science Laboratory) drive mechanism is a high precision linear actuator with a very large speed range. This mechanism was designed to work in a high vacuum environment in the International Space Station. Its purpose is to displace an oven with a large speed stability at low speed and to measure the position of the oven. Two different motors, connected together through a clutch mechanism, are used to achieve the very large speed range.

Design had also to take into account safety rules linked to manned flight and operations.

  • Speed: processing: 10-8 to 0.2 ·10-3 m/s
  • quenching: 10-3 to 0.1 m/s
  • Stroke: 204 mm
  • Operating temperature: +10°C to +60°C
  • Pressure: ambient to 10-5 Torr
  • Lifetime: 2 years of operation in orbit

Corner Cube Mechanism

The Corner Cube Mechanism (CCM) is a part of an interferometer. Its purpose is to displace very precisely a corner cube (mirror) in the optical path of the interferometer. The present mechanism was developed for the IASI instrument of the METOP satellite.

  • Speed: 132.5 mm/s
  • Average speed tolerance: < ±0.5 mm/s
  • Instantaneous speed variation: < ±1 mm/s
  • Maximum stroke: ±10.3 mm
  • Measurement accuracy of the position: < 0.01 mm
  • Stability of the origin during life: < 10 μm
  • Tilt of the mirror: < 30 arcmin
  • Lifetime: 7.3 ·108 cycles

Aerosol Collector Pyrolysor

RUAG Space has designed, manufactured, and tested a filter mechanism to collect aerosols particles from Titan (Saturn satellite) and bring them to an oven for “pyrolise”. The main difficulties of this mechanism were to withstand big thermal differences and the level of cleanliness required. So, tightness was an important issue and was solved by laser welding.

A specific choice of material was necessary to ensure the functionality after seven years under vacuum conditions with very few displacements.

Specific equipment (toolings) has been implemented to avoid any organic particles pollution.

Power consumption was also an important parameter.

  • Chemical cleanliness: < 10 ppb for CO2 and CO > 100 ppb for H2O and H2
  • Thermal variation from -200°C to +650°C (around oven)
  • Tightness: better than 10-8 mbl/s

This mechanism can be used for planetary exploration.

Refocusing Mechanism

RUAG space has developed a mechanism for refocusing optical telescopes. The mechanism provides commanded positioning of a mirror along one-axis with high thermal stability and high accuracy of < 0.001 mm. The mechanism mass is 1.85 kg, for a supported mirror mass of 0.55 kg.