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Sloshsat-FLEVO [Arianespace]

The Sloshsat-FLEVO (Sloshsat Facility for Liquid Experimentation and Verification in Orbit) is a satellite to investigate the behavior of liquids in weightlessness. The payload of the satellite consists of an experiment tank with elaborate instrumentation. The tank shape is a circular cylinder with hemispherical ends and no internal structures. The volume of the tank is 87 liters. The tank will be partially filled with 33.5 liters of water. With a sensor system, the liquid height at the tank wall will be measured at 270 locations. Additional sensors are provided at a few locations to measure liquid height with a better resolution, liquid velocity at the wall, pressures and temperatures. The mass of the dry satellite is approximately 70 kg. The fluid/rigid mass ratio is about 0.5.

The objectives of the Sloshsat-FLEVO experiment are to:

  • Obtain flight data to verify the adequacy of existing analytical fluid dynamics models, and indicate where improvement is needed
  • Obtain flight data to verify adequacy of existing computational fluid dynamics software numerical models, and indicate where improvement is needed.
  • Characterize the dynamic interaction between liquid motions and spacecraft
  • Provide understanding of the motions of liquid with a free surface in a low gravity environment
  • Generate phenomenological information on less well organized flow patterns as a basis for further mathematical modeling
  • Provide relevant information for the design of liquid management techniques in micro-gravity
  • Obtain data on diagnostic instruments performances.
  • and to develop and qualify a low-cost small spacecraft (S/C)-Bus

Sloshsat-FLEVO was to be launched on a Shuttle, as it was to use the Shuttle as a data relay. Only a non ISS flight was acceptable due to security reasons. But as no Shuttle flight opportunities were available due to the Columbia disaster, it has been modified for direct data transmission to enable launch on an Ariane-5ECA qualification flight. It will be released from top of the MaqSat B2 dummy payload.

Nation: Netherlands
Type / Application: Technology fluids in weightlessness
Operator: NLR, ESA
Contractors: NLR
Equipment: 87 liter Water tank with 33.5 kg water
Propulsion: 12 × cold gas thrusters
Lifetime: 10 days ?
Mass: 127 kg
Satellite COSPAR Date LS Launch Vehicle Remarks
Sloshsat-FLEVO 2005-005C 12.02.2005 Ko ELA-3 Ariane-5ECA with XTAR-EUR, MaqSat B2


  • NLR Website