Portal’s heat exchanger thruster, known as Flare, fires up during a test in a vacuum chamber. (Portal Space Systems Photo) Bothell, Wash.-based Portal Space Systems says it has successfully tested its ...

Engineers have built a modern Stirling engine that quietly turns the cold of outer space into steady mechanical power, using the night sky as a heat sink instead of a fuel tank. By radiating heat away ...

Jeff Thornburg helped turn a government research project into SpaceX’s most powerful rocket engine. Now, he’s trying to do the same thing at his startup Portal Space Systems, which is taking an idea ...

Space-based solar power represents a transformative shift in renewable energy, capturing sunlight in orbit and transmitting electricity to Earth continuously. Orbiting photovoltaic arrays receive ...