Sandia Lab Scientist Finds Heliostats May Detect Near-Earth Objects

Sandia National Laboratories scientist John Sandusky conducted nighttime experiments at the National Solar Thermal Test Facility utilising a heliostat – typically employed for concentrating solar energy – to explore the potential for detecting near-Earth objects such as asteroids. The research, part of a Laboratory Directed Research and Development project, aimed to measure the speed of asteroids relative to the stars, seeking to detect a femtowatt – one millionth of a billionth of a watt – of scattered sunlight. This approach, utilising existing software to oscillate the heliostat’s direction, offers a potential alternative to conventional asteroid detection methods reliant on imaging and computational analysis of observatory data.

The research, conducted as a Laboratory Directed Research and Development project, investigated the potential of repurposing existing heliostat infrastructure for asteroid detection. Heliostats, typically employed to concentrate sunlight onto a central receiver to generate energy, were tested for their ability to detect faint reflected light from near-Earth objects at night. The experiment leveraged the National Solar Thermal Test Facility, utilising one of its 212 heliostats without requiring any hardware modifications to the system.
The core principle involved measuring the velocity of asteroids relative to the background stars, differing from conventional planetary defence methods which rely on identifying asteroid streaks within images produced by observatory-grade telescopes. The sensitivity requirement necessitated detecting a signal of approximately one femtowatt – a millionth of a billionth of a watt – representing the intensity of sunlight scattered from asteroids. Existing software was employed to oscillate the heliostat’s direction, effectively scanning the sky and searching for objects moving at a different velocity than stationary stars. The research aimed to demonstrate the feasibility of utilising this existing infrastructure – currently unused at night – as a relatively low-cost system for detecting asteroids, potentially enhancing planetary defence capabilities. The approach, utilising asteroid detection heliostats, offers a different method to conventional imaging, focusing on velocity measurement rather than direct visual identification.