Solar Power Facility Innovates by Tracking Asteroids at Night
In a groundbreaking initiative, John Sandusky of Sandia National Laboratories is repurposing solar power technology to search for asteroids during nighttime. At the National Solar Thermal Test Facility in Albuquerque, New Mexico, Sandusky is experimenting with heliostat mirrors to enhance their functionality beyond energy generation.
Solar power systems are inherently limited; they cease operation when the sun sets, producing no energy until dawn. Sandusky’s project aims to change this by utilizing the facility’s heliostats for astronomical observations when the stars are visible. The National Solar Thermal Test Facility, the only research plant of its kind in the United States, features a 200-foot-high concrete tower and 218 mirrors that track the sun and concentrate sunlight for power generation, achieving a capacity of 6 MWt.
Transforming Heliostats into Astronomical Tools
To explore the potential of these heliostats, Sandusky initiated a project under the Laboratory Directed Research and Development program. He programmed one heliostat to track celestial objects and redirect reflected energy to optical instruments on the tower. Although this technique generated only a femtowatt of power, it created conditions suitable for detecting asteroids by oscillating the heliostat over a one-minute cycle.
Traditionally, astronomers rely on optical telescopes to identify asteroids through long exposure time-lapse images, where asteroids appear as streaks against the backdrop of stars. This method is constrained by the limited number of telescopes and the vastness of the sky, leading to many discoveries by amateur astronomers. Given the dual nature of asteroids as potential resources and threats to Earth, the need for enhanced detection methods is critical.
Innovative Detection Techniques
Sandusky’s method deviates from conventional imaging techniques. Instead of capturing visible streaks, it analyzes the photocurrent power spectrum of incoming light with sub-milliHertz resolution. When an asteroid or a spacecraft crosses the field of view, it manifests as a frequency shift relative to the surrounding starlight, indicating changes in its trajectory.
While this approach does not provide the dramatic visuals of traditional methods, it suggests a promising avenue for utilizing dormant solar power facilities as cost-effective supplements to NASA’s Asteroid Terrestrial-impact Last Alert System (ATLAS), which is tasked with identifying hazardous asteroids.
Sandusky also noted potential military applications of this technology, such as detecting clandestine spacecraft in cislunar space. However, advancing the technique to practical use remains a challenge. “We’re looking for opportunities to scale up from one heliostat to many and try to demonstrate that we can help find near-Earth objects,” he stated. “We also want to demonstrate we can scale up the technology to detect even smaller asteroids.”
Sandusky presented these findings at a recent conference organized by the International Society for Optics and Photonics, highlighting the innovative intersection of solar energy and astronomical discovery. As research continues, the collaboration between energy and space technology may lead to enhanced asteroid detection capabilities and new insights into our solar system.
