'Ghost photography' satellite helps China hunt US stealth aircraft

Chinese spy satellites using ghost imaging technology are said to be able to detect US B-2 stealth bombers.

B-2s always fly at night to avoid detection. Photo: USAF.

China is developing a spy satellite that uses ghost imaging technology to detect advanced US stealth bombers. If successful, the project could be a game changer in East Asia over the next 10 years, SCMP reported on November 26.

Chinese physicists say current camouflage techniques, from smoke screens to hide forces on the battlefield to radar-absorbing materials on stealth aircraft and warships, will be useless against ghost photography technology.

Quantum ghost imaging technology can achieve unprecedented sensitivity, based on the principle of detecting the tiny amount of light emitted by objects with extremely low reflectivity, as well as how the target interacts with light in the surrounding environment. This allows ghost imaging technology to collect more target information than traditional methods.

Satellites equipped with new quantum optical sensors are capable of identifying and tracking targets that are almost invisible to radar and infrared optical sensors, like stealth bombers flying at night.

The B-2 Spirit is currently the world's only stealth bomber capable of carrying out strategic strikes against the enemy. It mainly flies at night to avoid high-definition optical cameras on spy satellites. The bomber is coated with special paint to scatter or absorb radar waves in certain bands, as well as equipped with a variety of heat diffusion technologies to avoid infrared sensors. The B-21 model under development also retains the above technologies, but is significantly improved and is expected to be put into service with the US Air Force in 2025.

Gong Wenlin, director of the Quantum Optics Laboratory at the Shanghai Academy of Sciences, which built the prototype satellite ghost imaging device, said the technology is designed to force stealth aircraft like the B-2 to reveal themselves. The first prototype is expected to be launched in 2020, with the goal of space testing by 2025 and mass deployment five years later.

The technology has already been tested on ground systems. Mr. Wenlin’s team is racing against foreign rivals, including the US military’s research lab, to launch the world’s first ghost imaging satellite.

China tested the feasibility of this technology on a ground system in 2011, three years ahead of the US. "We beat them on the ground and are very confident of winning the space race," Mr. Wenlin declared.

The ghost imaging satellite will carry two cameras and two laser emitters. Illustration: Breaking Defense.

Ghost imaging satellites will be equipped with two cameras. The first will aim a large single image sensor at the suspected area, while the second will measure changes in the ambient light around the area. The target may reflect small amounts of light from sources such as the Sun, Moon, or even fluorescent lights. The satellite will also be equipped with two laser emitters to illuminate the target and its surroundings.

By analyzing and combining signals captured from two cameras using quantum physics algorithms, scientists can capture images of objects with extremely high definition, never achieved with previous methods.

Wenlin said the technology is not affected by darkness, clouds, fog, and other factors that hinder visibility. Photonic imaging technology can capture data from multiple light bands, making the images appear more natural to the human eye than black-and-white radar images, which rely on reflected electromagnetic waves.

Ghost cameras can also determine the physical and chemical properties of targets. This helps operators distinguish between dummies or well-concealed equipment. Chinese experts say ghost imaging technology will be most effective when combined with traditional methods such as optical cameras and synthetic aperture radar.

Professor Xiong Jun of Peking University said ghost imaging technology could be a game changer in military operations. However, to successfully build a ghost imaging satellite, China still needs to overcome many technical challenges.

If a satellite uses natural light sources like the Sun and Moon, it will need ultra-sensitive sensors to detect tiny changes in light that can last a billionth of a second. If it uses artificial light sources like lasers, it will need very powerful emitters to shine on targets close to the ground.

According to VNE