Micro-VCM facility at the DLR Institute of Space Systems in Bremen.
All materials outgas as soon as they are exposed to a vacuum. Outgassing greatly depends on the material and its conditioning, the operating temperature and the time spent in vacuum. For space applications, outgassing can lead to serious problems, particularly when part of the released gas condenses onto an adjacent surface. The qualification of all materials used with regard to outgassing is therefore of utmost importance when developing hardware for use in space. This also applies to materials that are used in vacuum facilities for testing flight hardware, and which could lead to contaminations before the start of the actual mission.
The micro-VCM facility is responsible for the implementation of outgassing tests in accordance with the ESA Standard ECSS-Q-ST-70-02C, 'thermal vacuum outgassing test for the screening of space materials'. The test determines three outgassing parameters, which are often used when selecting materials for space applications:
TML (Total Mass Loss): The percentage of mass loss in a sample after exactly 24 hours in a high vacuum at a temperature of 125 °C. The sample is first stored for 24 hours at 55 % rH (relative humidity) and 22 °C.
RML (Recovered Mass Loss): The percentage of mass loss in a sample material after exactly 24 hours in a high vacuum at a temperature of 125 °C, and a post-conditioning of 24 hours at 55 % rH and 22 °C.
CVCM (Collected Volatile Condensable Material): The percentage mass of a contaminant on the collector plate (temperature of 25 °C) positioned above a sample after exactly 24 hours in a high vacuum.
The ESA Standard establishes the following requirements for the selection of materials for general use in space: RML < 1.00 % and CVCM < 0.01 %. NASA Standards often require: TML < 1.00 % and CVCM < 0.01 %.
The micro-VCM facility has been accredited by the German accreditation body DAkkS for applied testing procedures in accordance with DIN EN ISO/IEC 17025:2005.
The facility meets all the requirements stipulated in ECSS-Q-ST-70-02C. Up to 4 materials can be tested at any one given time.
TML, RML, CVCM
IR transmission measurements of the contaminant are available upon request
In general, 10 g per material. For very light samples, other arrangements are available upon request