Space shuttles History 11 Accidents 10 Astronauts 7 Astronautics 4 Exploration 4 Propulsion systems 4 more ... Space flights 4 Technological innovations 4 Maintenance and repair 3 Reusable space vehicles 3 Space flight 3 Space vehicle accidents 3 Appropriations and expenditures 2 Costs 2 Finance 2 Government policy 2 Launch vehicles (Astronautics) 2 Manned space flight 2 Meteoroids 2 Planning 2 Risk assessment 2 Risk management 2 Space debris 2 Space sciences 2 Space stations 2 Space vehicles 2 Technology assessment 2 Aerospace engineers 1 Air 1 less ...