Earth's low orbit is filled with satellites — some new, some decades old. This has become an issue as orbit fills with space debris from broken or failed satellites, making removing them a challenge.

If you tried to start a car that’s been sitting in a garage for decades, you might not expect the engine to respond. But a set of thrusters aboard the Voyager 1 spacecraft successfully fired up ...

It sounds like a NASA pipe dream: a new spacecraft thruster that’s up to 40 percent more power efficient than today’s. Even better, its fuel costs less than a thousandth as much and weighs an eighth ...