"We're trying to encounter an astronomical object that streaks through our solar system just once and we don’t want to miss ...

Portal Space Systems has raised $17.5 million to accelerate the development of a space vehicle with a solar thermal ...

Bothell, Wash.-based Portal Space Systems shows off the lab where its solar thermal propulsion system will be developed.

The same dirt that clings to astronauts' boots may one day keep their lights on. In a study published in Device, researchers ...