The shot-down Chinese spy balloon may have had synthetic aperture radar, the Washington Post reports.
The technology has the ability to observe objects in the dark or through clouds.
SAR is used around the world by organizations like NASA and the European Space Agency.
In February, a high-altitude balloon with surveillance capabilities connected to China flew over the continental US before being shot down over the Atlantic.
At the time, much about the balloon wasn't known publicly, but a new trove of Pentagon documents leaked on Discord show it — and up to four other previously unknown spy balloons like it — could have had a feature known as "synthetic aperture radar" that can see through certain objects, the Washington Post reported.
Jack Teixeira, a 21-year-old US National Guard airman, was arrested Thursday in connection to the leaks.
US intelligence agencies believed this because the balloon, which officials named Killeen-23 in an apparent reference to 1940s mobster Donald Killeen, was equipped with the ability to generate up to 10,000 watts of solar power — enough to power a typical home — which could support such abilities.
"The amount of solar power generated by the panels on the Chinese stratospheric balloon that NSA named Killeen-23 is excessive for a weather balloon," the document reads.
Synthetic aperture radar is the solution to the problem with real aperture radar, which cannot create high-resolution images without an impractically large antenna. SAR "synthesizes" a large antenna, but the concept is the same — it releases bursts of electromagnetic energy to an object on Earth, and a sensor then records the wavelength of energy it receives back, according to NASA. These sensor readings then allow the radar to create a reconstruction of whatever objects are below the energy beam.
Because SAR isn't taking photos and is instead using electromagnetic data to create a high-resolution image, the technology can "see" in the dark, as well as through clouds, smoke, soil, and rain. It can also help with three-dimensional reconstructions, unlike cameras, which can only capture what is openly visible from above.
The technology, invented in 1951, is used all over the world by science organizations like NASA and the European Space Agency to observe the earth's topography.
It is also used in war to spy on adversaries. Recently, a Canadian satellite operator helped Ukraine by providing SAR imagery to officials. The imagery allowed Ukrainian officials to monitor Russian troop movements during inclement weather and cloudy days.
The documents also reveal that certain functions of the balloons are still unknown to US intelligence, as certain sensors on the device are labeled as "unidentified" in photos.
The Pentagon did not immediately respond to Insider's request for comment.
Read the original article on Business Insider