tokens: The user shall define the modelling requirements and where quantitative levels are required use a physical outgassing and contamination transport model . NOTE 1 No specific outgassing and contamination transport model is defined as requirement . The physical model , given in Annex K can be used for the analyses in all cases . NOTE 2 When the spacecraft is not sensitive , outgassing modelling can be based on VCM­test results [ RD.23 ] , [ RD.24 ] , differentiating between CVCM ( low vapour pressure , condensable material ) for room temperature range and TML ( sum of condensable and non­condensable material ) for cryogenic applications . NOTE 3 For information , tools with different level of complexity , which treat outgassing and contamination are given in Annex K.