On 25 April, the "Times of India" published an article saying: The Norfolk Naval Base of the US Navy has been unveiled by China's "spy satellites"! The article described the Norfolk Naval Base, the largest naval base in the US Navy mainland, has been photographed by China's "commercial synthetic aperture satellites." Not only did they photograph a large number of U.S. Navy warships moored at the pier at that time, but they could also clearly distinguish 3 Nimitz-class aircraft carriers, 2 Burke-class destroyers and 1 amphibious assault ship. It also highlights the Chinese commercial satellites that took the images, pointing out their enormous military potential, such as the ability to track and monitor U.S. aircraft carriers or warships.
In fact, the "Times of India" named China's "spy satellite" is the Taijing-4 03 satellite developed by the mainland's Beijing Micro-Nano Star Technology Co., Ltd. On January 23 this year, the Lijian-1 Yao-3 carrier rocket developed by Zhongke Aerospace was successfully launched at the Jiuquan Satellite Launch Center in the form of "one arrow and five satellites", and successfully sent five satellites of the Micro-Nano Star Company, including the Taijing-4-03 satellite, into the scheduled orbit. It has been learned that these satellites will be mainly used in scientific research, space exploration, environmental surveys, and other fields.
In fact, after the release of this batch of satellite pictures taken by the Taijing-4 03 satellite in March 2024, many people commented that the quality of China's satellites is too poor, not to mention the color, and the shooting is so blurry, and the aircraft carrier and warship can only see an outline, and the details are not clear at all.
What they don't know is that in fact, the Taijing-4 03 satellite photography mode is not the familiar "optical mode", but a special satellite that uses high-resolution SAR (synthetic aperture radar) for imaging, and it is also the first commercial Ku-band phased array radar imaging satellite in China. Therefore, the satellite pictures taken by it are not as colorful and clear as the photos, but they can ignore the influence of objective factors such as the night sky, clouds, rain and fog, and use the Ku-band with high frequency and strong penetration to take delicate target radar images.
In fact, if you want to talk about "details", although the radar pictures taken by synthetic aperture radar are not as clear as those of high-resolution optical satellites, these pictures taken by the Taijing-4 03 satellite are almost the best results at night and in harsh weather conditions where optical satellites are powerless. For example, we can clearly identify not only the large aircraft carriers on the docks of the Norfolk Naval Base, but even when zoomed in, we can clearly see the four catapult tracks on the deck and the flame shield at the end, as well as the retainers on both sides of the runway in the landing area that fix the interception cables. And it can also be judged from the square bow of the amphibious assault ship and the position of the outboard elevator on the left side that this is an "American" class, not a "Wasp" class with missing corners on both sides of the bow and the elevator closer to the stern.
"Graveyard" of US military aircraft
These "details" captured by synthetic aperture radar can fully meet the needs of searching for specific targets and tracking and monitoring. In fact, the resolution of the Taijing-4 03 satellite has reached the "sub-meter level" of 0.5 meters, which is also considered a cutting-edge level among commercial synthetic aperture radar satellites. In addition, it also has a variety of imaging modes such as beaming, striping, and scanning, and the observation width of the sliding mode can reach more than 10 kilometers.
Diagram of the unfolding of a flat-panel satellite in space
However, the biggest feature of the Taijing-4 03 satellite is that it adopts a "flat-panel satellite configuration", and it also compresses the weight to an astonishing 230 kilograms, which is far lower than the average level of about 300 kilograms in foreign counterparts. These two features can not only greatly reduce the launch cost, but also launch more satellites at a time in the "multi-satellite stacking" mode, laying the foundation for subsequent large-scale satellite networking. You know, as long as anything can be "networked", then its ability will be exponentially amplified!
The United States has been monitoring the construction of continental aircraft carriers with synthetic aperture radar satellites for many years
You must know that now developed countries around the world are establishing their own dual-use synthetic aperture radar constellations, and commercial synthetic aperture radar constellations are now a hot spot for development. Even the U.S. military, which has a large number of military satellites and top technology, is buying images of commercial synthetic aperture radar satellites all year round. Even in the Russian-Ukrainian war, it purchased satellite images from commercial companies to provide them to the Ukrainian army, helping it successfully fight a counteroffensive in 2023.
Therefore, although the mainland already has better synthetic aperture radar satellites in the field of military constellations, it still needs to be supplemented by satellites from a large number of commercial companies. After all, satellites will be limited by time and quantity, and there may be a "blind spot" for the acquisition of target images for emergencies, and commercial satellites can be used as a good substitute at this time. For example, the severe weather that accompanies sudden natural disasters has greatly limited the shooting of optical and infrared satellites in the disaster area, and at this time, the synthetic aperture radar of the Taijing-4 03 satellite can penetrate the clouds to obtain images of the disaster area.
The 01 star of Taijing No. 4 has already been photographed at Taiwan's Zuoying Military Port
Of course, what everyone is most concerned about is the military use of the Taijing No. 4 03 star. Because the Taijing-4 03 satellite adopts the new Ku-band phased array radar payload technology, and the synthetic aperture radar map taken can realize AI intelligent processing and backhaul back on the "satellite", it can not only meet the needs of rapid detection and identification of sea and airport targets, but also has the special ability of "moving target" monitoring!
Kennedy Space Center, Workstation 39B, USA
After these two "special abilities" are combined, will everyone be able to see the "top use" of the Taijing-4 03 star? Yes, it is to continuously monitor the fighter planes taking off from the airport and the warships sailing in the ocean. In fact, as early as many years ago, the video satellite developed by Changguang in the mainland realized the continuous flight and shooting of the US military aircraft, so although the Taijing-4 03 star did not mention that it has similar functions, but through multiple pictures and coordinate positioning, and fusing it with the automatic identification system of flights or ships, it can obtain the precise positioning, movement direction and other information of some fighters and large warships.
Information on the bearing of a US warship on the AIS
This capability does not have to be used in wartime, and in peacetime we can also "take pictures" of US warships and aircraft carrier strike groups that enter the vicinity of the mainland and make them public. This can not only be used as evidence that the United States poses a threat to the mainland's security, but also let it know that its every move has been accurately grasped by our side, and the coordinates have already been written into the "delivery note" of the "Dongfeng Express." This is nothing less than a silent deterrent to the US military!
As for whether the Taijing-4 03 satellite and the commercial satellites of other continents are considered "spy satellites", there is actually nothing to discuss. After all, military agencies in many countries around the world, including the U.S. military, have purchased commercial satellite images. And it is now difficult to judge whether a satellite is a "spy satellite" or not, because most satellites have dual-use capabilities, so this old "Cold War" name should also be forgotten.
Perhaps it is because India has not had a satellite with such a technical level as the Taijing-4 03 satellite until now, so it is called a "spy satellite" to vent!