Space debris sensor promises safer future for satellites

A large cloud of tiny fragments revolves around Earth following satellite explosions, rocket stage malfunctions, and anti-satellite missile testing. These fragments—some as small as grains of sand—rotate around the planet at speeds greater than 17,000 miles per hour. Even small fragments may blast through spacecraft walls, cripple necessary systems, and shorten mission lifetimes.

To counteract such a threat, engineers at the Southwest Research Institute (SwRI) have built and tested a new system designed to detect and assess the hyperfast impacts before they can cause real damage. The project, led by Institute Scientist Dr. Sidney Chocron, integrates leading-edge materials, strain-sensing technology, and high-speed testing methods to give spacecraft operators useful data about otherwise unseen peril.

The tool is not simply a guard. It is an ear surface, two plates with a small gap between them. There are sixteen minute strain gauges—eight in front and eight at the rear—along the structure to track the vibrations of the impacts. Upon a micrometeoroid or a piece of orbital debris striking into the surface, the shock propagates through the plates. The waves are measured in real time, converted into data, and returned to Earth.

The result is a system not only notifying a spacecraft that it has been hit, but also when, at what speed, and by what kind of particle it was hit. This can be crucial when making plans for future missions. "Most spacecraft weather minor impacts without systems failing or operators on Earth aware," Chocron said. "By sending information back to Earth with the important insights before any damage is done, it can even influence future design decisions."

To experiment with such a system in orbiting spacecraft would be dangerous and expensive. In reaction to this, SwRI employed its light gas gun—a machine capable of firing minuscule projectiles at astronomical velocities in a vacuum chamber. The configuration mimics the conditions of outer space, where air resistance vanishes and debris travels faster than bullets from rifles.

Panels that were mounted with the detection system were shot at these high-speed particles in a series of eight full-scale tests. Each test was replicated by a 3D CTH simulation, which is a computer program that models impact dynamics in great detail. What they discovered was that the system could detect impact events routinely, including location, velocity, and even composition components. Such observations are well beyond simple impact detection. They help scientists understand the population of small bits of trash that surround Earth but are too tiny to track from the ground.

While it is impossible to reproduce every condition of the space environment, our tests produce realistic particle impacts," Chocron said. "This allows us to ascertain whether or not structures are capable of withstanding such impacts. It also enables us to assess the effectiveness of the MMOD detection and characterization system that can identify when and where impacts happen as well as the velocity and composition of the debris involved."

The possibilities of this system go beyond real-time monitoring of spacecraft health. Data from these sensors can be shared with satellite operators on the same orbital paths, warning others when debris activity is highest. A collaborative safety net, where one satellite's run-in with debris could save another.

Though the device will not stop impacts from happening, it does provide crucial early warning. By providing engineers and mission planners with accurate impact data, the technology helps to create stronger spacecraft and better-informed reaction to the evolving field of orbital space debris.

NASA and the broader space industry can use these findings to enhance shielding methods and design more durable spacecraft in the future. With thousands of satellites expected to be orbiting Earth in the coming decade, such information is increasingly precious.

The far-range vision takes it farther. With an adequate number of sensors placed around spacecraft, scientists would be able to create a dynamic map of the debris field orbiting the Earth. Such a map would reveal regions of perilous particle fields, track changes over time, and guide safer navigation through thick orbital space.

"Ultimately, our main aim is to map and characterize the MMOD debris field around the Earth to better safeguard future missions," said Chocron. "Our MMOD detection and characterization system is a step toward better understanding and mitigating those threats."

The project is currently looking for funding for a flight-capable version of the device. When launched, it could revolutionize the way spacecraft handle the quiet but deadly threat of orbital debris.

Today, more than 30,000 pieces of monitored garbage larger than a softball orbit Earth. Millions of objects smaller than a baseball, while invisible to ground sensors, pose an equal or even greater risk. Even millimeter-sized particles can be able to penetrate thermal protection or destroy solar panels.

The Kessler Syndrome, a hypothesis advanced by NASA engineer Donald Kessler in 1978, warns that runaway debris accumulation could trigger a series of collisions. That chain reaction could make entire orbits useless for years to come. Devices like the one demonstrated at Southwest Research Institute could be employed to slow or avoid that outcome.

Until "now," the work demonstrates detection, "not dumb luck," to be possibly the smarter option. By listening to every little buzz, spacecraft could finally get the sensitivity required to survive the increasing hostility. of the orbital environment.

Research findings are available online in the Hypervelocity Impact Symposium.

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