<b>Framework for Safety Critical System Software</b> U R Rao Satellite Centre URSC is the lead centre of the Indian Space Research Organisation in the development and operationalisation of satellites for communication, navigation and remote sensing applications. It also has launched many interplanetary missions. Now execution of “GAGANYAAN” is planned in phase manner. In the initial phase, test vehicles will be used to demonstrate the abort capability during different phases of mission i.e. development and qualification testing of Crew Escape System CES and recovery. Subsequently, two unmanned flights are planned prior to human spaceflight to demonstrate the manned mission capabilities. As humans are involved software safety plays a critical role. Presently ISRO is having ISRO Software Process Document ISPD based on IEEE 12207 2015 framework for software life cycle activities. For Gaganyaan project considering safety in to picture additional software safety standard is brought out based on DO178C. To develop and certify safety critical software ISRO software control board has brought out the ISRO software safety standard for a transition from mission critical software to safety critical software development. This paper discusses how to incorporate safety and security standard in addition to the existing ISPD standard. ISRO Software Safety Standard ISSS , Preliminary Hazard Analysis PHA , SubSystem Hazard Analysis SSHA , ISRO Software Process Document ISPD , Software Fault Tree Analyses SFTA , Software Failure Modes and Effects Analyses SFMEA , Software Certification Process SCP , Software Hazard List SHL , Software Certification Process SCP , Independent Verification and Validation IVandV 1541-1544 Issue-4 Volume-5 Savitha. A | Sudeesh B