Forward-looking: Traffic in low Earth orbit has surged in recent years. The growing number of satellites is now pushing scientists to develop new management and tracking solutions, as GPS and ground-based stations can sometimes be unreliable or unavailable. The Los Alamos National Laboratory has introduced the "Spacecraft Speedometer," a novel technology for tracking satellites in low Earth orbit. This compact, resource-efficient device can precisely measure a satellite's speed as it orbits the planet. Researchers believe it could also serve as a tracking solution for deep-space missions.Designed to provide onboard, real-time velocity measurements, the Spacecraft Speedometer enables space agencies and commercial operators to predict satellite positions and execute orbital maneuvers to avoid collisions with other satellites or space debris.Los Alamos developed the system in response to increasing congestion in LEO, where the number of active satellites surged from 2,287 in 2019 to over 10,000 in 2024. With the rise of mega-constellations, traffic management challenges are expected to grow even more severe.Current methods for tracking satellite speed and position rely on GPS or ground-based radars. While GPS works when a satellite has a functioning receiver, it can become unreliable during solar storms. Ground stations, meanwhile, can only track orbiting objects intermittently sometimes just once every few hours or days.The newly introduced Spacecraft Speedometer offers a more reliable alternative to both systems, providing continuous velocity data even during extreme space weather. Researchers also suggest it could track orbital insertions in other planetary atmospheres, monitor local space environments, and measure dangerous particle charging levels. // Related StoriesThe device achieves these capabilities through its twin laminated plasma spectrometers, which measure charged particles (ions and electrons) striking the front and rear of a spacecraft. Los Alamos researchers compare this process to a car driving through heavy rain: more raindrops hit the front windshield than the rear. By analyzing this difference, the Spacecraft Speedometer can determine a satellite's speed and position in real time.