Chinese scientists turn largest Earth surveillance network satellite upside down to hunt killer asteroid
A giant asteroid hurtles towards Earth on a path that could potentially end in disaster.

Known as 1994 PC1, it is as big as San Francisco’s Golden Gate Bridge, but as astronomers try to pinpoint its exact position, its distance of two million km – five times as far from Earth as the moon – poses a significant challenge.

But there is a solution: a Chinese Jilin-1 satellite in a near-Earth orbit. Normally it observes our planet. Instead, it executes an unprecedented manoeuvre. It flips over, aims its lens into the depths of space and begins snapping photos each second. These images not only capture 1994 PC1 – they also help scientists reduce the orbit positioning error of the asteroid to just 33km, improving the ground-based telescopes’ accuracy by two orders of magnitude.

Astronomers can now definitively see that 1994 PC1 is not on a collision course with Earth, but will pass safely by.

This was a mission that took place in January 2022, but has only now been revealed after recently being declassified by the Chinese government.

And it sheds new light on the powerful observation capabilities of Chinese satellites. These are capabilities that are causing concern for Western countries, particularly the United States, as they worry that China’s growing space power could be used for military purposes.

But researchers detailing the 2022 mission have said that China will continue to hone these skills to protect humanity.

“Follow-up experiments will be conducted to observe fainter near-Earth asteroids using existing space-based equipment,” the project team, led by Professor Liu Jing with the National Astronomical Observatory of the Chinese Academy of Sciences, wrote in a peer-reviewed paper published in the Chinese Journal of Deep Space Exploration in April.

More than 100 satellites make up the Jilin-1 constellation, currently the largest Earth observation network in operation. These satellites are incredibly powerful, capable of quickly capturing high-resolution images of almost any location on Earth. They have even tracked and filmed an American F-22 fighter jet flying in clouds and a rocket blasting off a launch pad.

But asteroids in deep space are quite different targets from stealth fighter jets, and the Jilin-1 satellites were not initially designed to operate with their telescopes turned the wrong way around.

After a thorough analysis of the satellites’ capabilities, the project team determined that tracking 1994 PC1 was technically feasible but required in-depth adjustments to critical equipment, such as the exposure parameters of the optical sensors.

“The Jilin-1 video satellite needs to continuously adjust its altitude during orbit motion to perform fixed-point gaze imaging on the target observation area,” Liu and her colleagues said in the paper.

“A total of 51 shooting tasks were arranged during the period from January 17 to 21, 2022 ... with each imaging mission lasting 15 seconds,” they added.

The European Space Agency has been studying the use of some dedicated satellites to observe asteroids for more than two decades, and Nasa has conducted similar research. But their ideas are still on paper.

Meanwhile, China’s successful experiment shows humankind can enhance its perception and early warning capabilities for high-risk asteroids by using existing space-based Earth observation systems, according to Liu’s paper.

The experiment also shows China’s space-ground collaborative capabilities from a new perspective. The researchers employed two large ground observation stations located in Beijing and Xinjiang, along with a dedicated satellite for astronomical observation, to coordinate with Jilin-1.

In the next step, they plan to incorporate a large ground-based radar network to further enhance the scope and accuracy of tracking and targeting, Liu said.

Globally, the US has by far the most space assets, with more than 8,000 satellites currently in orbit – 12 times the number of Chinese assets.

However, most US assets are SpaceX’s Starlink satellites, primarily used for communication rather than intelligence gathering.

The US military has recently raised alarms about the rapid growth of China’s space observation system capabilities, including Jilin-1, believing they pose an unprecedented threat to US military forces worldwide.

At the Mitchell Institute for Aerospace Studies’ Spacepower Security Forum held in Washington on March 27, chief of space operations General B. Chance Saltzman said China’s growing fleet of intelligence, surveillance and reconnaissance (ISR) satellites is creating the “kill webs” that the US military dreads most.

“Specifically the PRC has more than 470 ISR satellites that are feeding a robust sensor-shooter kill web,” Saltzman said in his keynote address. “This new sensor shooter kill web creates unacceptable risk to our forward-deployed force. This is something that most of us are just not used to thinking about.”

At the same forum, Kelly D. Hammett, director of the Space Rapid Capabilities Office, also warned that the US could be falling behind in a race against China to build a proliferated warfighter architecture.

“We have a lot of irons in the fire. We’re building new capabilities, trying new things, trying to get to assets on range that the operators can test and train against,” Hammett said.

“(But) it’s not the force structure overall that we’re going to need to be able to compete and deter and potentially fight and win against the vast array of assets the Chinese are putting on orbit. There are 400 ISR birds, they’re launching 100 satellites a year, and most of them are very insidious. Well over half of them are space warfighting satellites. They’re not largely commercial,” he added. – South China Morning Post
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Details have been revealed of a 2022 mission by a satellite so powerful it can see an ultra-dim target in space from 2 million km away. It has shed new light on China’s satellite capabilities, and may give the US more cause for concern over Beijing’s growing space power.