Contamination effects and analysis

Contamination from outgassing, venting, leaks and thruster firing can degrade surfaces on which contaminants deposit. The contaminant cloud can also disrupt payload operations (e.g telescopes). On-orbit contamination may modify surfaces and invalidate ground-based characterisation, e.g. charging properties measurements. High contaminant levels may also contribute to the onset of electrostatic discharge.
ESABASE/Outgassing has been developed to compute deposition on surfaces of a 3-dimensional model of a spacecraft resulting from the outgassing of other surfaces. Account is taken of direct flux, flux reflected by other surfaces, reflections from other contaminant molecules ( using a simplified cloud model), and ambient gas scattering. A temperature -dependent residence-time model is used for the outgassing.

Recently, a new software tool for contamination analysis has been developed: COntamination Modelling Outgassing & Vent Analysis tool (COMOVA).

It was developed by the Space Environment Department (DESP) of ONERA (physics modelling) and HTS (interfacing and pre-processing) and was funded by Space Environments and Effects Analysis Section.

Contamination is a serious problem for International Space Station payloads - both contaminant deposition on experiments and contaminants in fields of view of telescopes. A tool for contaminant cloud predictions leading to a better scattering model and giving column densities and irradiances in fields of view is required.
Last update: 29 March 2007

Related sites:

 •  Space Environment Information System (
 •  Geant4 for space (
 •  SSAT (
 •  GRAS (PDF) ( &arnumber=1589198 &isnumber=33493)
 •  ESABASE2/Debris (
 •  MASTER-2005 (
 •  Martian Climate Database (
 •  COMOVA (
 •  SPIS (
 •  Spacegrid (