This International Standard provides small auxiliary spacecraft (SASC) and launch vehicle (LV) organizations with basic rules for writing an interface control document (ICD), and a general format for the document's presentation, when the SASC has an interface (I/F) only with the LV. It is applicable to the necessary ICD items and restrictions peculiar to SASCs, these spacecraft being as defined in the contract between the launch agency and the contractor. The payload area covered by this International Standard is limited to SASC. NOTE SASCs have minor priorities with respect to the main spacecraft.