Future human space exploration depends on essential progress in space transportation. The international INPPS (International Nuclear Power and Propulsion System) flagship project has the goal to bring together international partners in a hybrid approach of solar energy, chemical and nuclear electric powered space transportation. It will serve a human to Mars mission and in a second step the exploration of the Jupiter moon EUROPA. Since 2009 detailed technological, scientific, commercial and legal (Nuclear Power in Space (NPS) requirements) preparations related to INPPS are in progress, inter alia an EU-Commission collaboration consortia and a number of bilateral initiatives with Brazil, Costa Rica, Israel, Japan and USA. After 2022, the INPPS flagship extended international strategy includes more European entities (Czech Republic, Netherlands and Poland) as well as potentially India plus Pacific nations. In 2023, the Indo-Pacific Space Conclave White Paper stated a coherent plan for international collaboration in space activities with a focus and benefit of humankind applied to human Mars flight with the INPPS flagship. Insofar still realistic: the 2028-2032 INPPS subsystems autonomous robotic plus astronautic assembly in Earth orbit with space qualifications towards Mars and by Earth return. Up to 18 t - in form of scientific, commercial and communication payload - also means the heaviest space tug, usable to gain profits by space manufacturing (the next space commercialization step). Due to laser communication between INPPS and Earth ground, virtual real-time human participation is already an international highlight for long-term, continuous promotion and acceptance.