Chinese scientists turn the largest satellite in an Earth monitoring network upside down to hunt the killer asteroid

Astronomers can now say with certainty that 1994 PC1 is not on a collision course with Earth, but will fly past it safely.

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

And it sheds new light on the powerful observation capabilities of Chinese satellitesThese capabilities are a concern for Western countries, especially the United States, who fear that China's growing space power could be used for military purposes.

However, researchers announcing details of the 2022 mission have said China will continue to refine these capabilities 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 of the National Astronomical Observatory of the Chinese Academy of Sciences, wrote in a peer-reviewed article published in April in the Chinese Journal of Deep Space Exploration.

More than 100 satellites form the Constellation Jilin-1the largest active Earth observation network currently in operation. These satellites are incredibly powerful and can capture high-resolution images of almost any location on Earth in a short period of time. They have even tracked and filmed an American F-22 fighter jet flying in the clouds and a rocket taking off from a launch pad.
The Chinese satellites were used to track an American F-22 fighter jet. Photo: Getty Images/TNS
But Asteroids in space are very different targets than stealth fighter jets, and the Jilin-1 satellites were not originally designed to operate with telescopes turned upside down.

After a careful analysis of the satellites' capabilities, the project team concluded that tracking 1994 PC1 was technically feasible but required major 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 to perform fixed-point imaging of the target observation area,” Liu and her colleagues explained in the article.

“During the period January 17-21, 2022, a total of 51 imaging tasks were performed… with each imaging mission lasting 15 seconds,” they added.

The European Space Agency has been studying the use of special 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 that humanity can improve its perception and early warning capabilities against high-risk asteroids by using existing space-based Earth observation systems, Liu's article says.

The experiment also shows China's space-ground cooperation capabilities from a new perspective. The researchers used two large ground observation stations in Beijing and Xinjiang, as well as their own satellite for astronomical observations, to coordinate the cooperation with Jilin-1.

The next step is to integrate a large ground-based radar network to further improve the scope and accuracy of tracking and target acquisition, Liu said.

The United States has by far the largest space resources in the world; there are currently more than 8,000 satellites in orbit – twelve times more than the Chinese.

However, most US assets are SpaceX Starlink Satellites that are used primarily for communication rather than for information gathering.


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The US military recently raised the alarm about the rapid growth the capabilities of Chinese space observation systems, including Jilin-1, and believes that they have a unprecedented threat to US forces worldwide.

Speaking at the Mitchell Institute for Aerospace Studies' Spacepower Security Forum in Washington on March 27, Chief of Space Operations Gen. B. Chance Saltzman said China's growing fleet of reconnaissance, surveillance and information (ISR) satellites is creating the “killer networks” the U.S. military fears most.

“In particular, the PRC has more than 470 ISR satellites supporting a robust sensor-shooter-kill network,” Saltzman said in his keynote speech. “This new sensor-shooter-kill network poses an unacceptable risk to our forward-deployed forces. This is something most of us are simply not used to thinking about.”

At the same forum, Kelly D. Hammett, director of the Space Rapid Capabilities Office, warned that the United States could fall behind in the race with China to build a proliferated ordnance disposal architecture.

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

“(But) it's not the total force size that we need to be able to compete with, deter and potentially fight and win against the huge range of assets that the Chinese are putting into orbit. There are 400 ISR satellites, they launch 100 satellites a year and most of them are very insidious. Well over half of them are space warfare satellites. They're not predominantly commercial,” he added.