At the end of 2019 China released photos taken by its Gaofen 8 imaging satellite, which had been launched in November. This bird is in a 500 kilometers high orbit and is equipped with multispectral cameras with a very precise laser system to determine the attitude of what it is taking a picture of and do that in such detail that 3D images of the landscape and even structures are clearly visible in the photos. These pictures can even spot a person, whether they are lying down or standing up. This is major progress in Chinese capabilities. Despite that China is still playing catchup to American imaging satellites. Gaofen 8 shows China moving fast to match American tech. The Gaofen series satellites are built to last at least eight years and they will be replaced by even more capable imaging satellite technology.
In July 2018 China put the first of these new photo satellites into orbit. This Gaofen 11 optical remote-sensing satellite had a resolution of 10cm. That means it is able to capture objects on the surface that are less than four inches wide. Previously only American photo satellites had that degree of resolution. Current American photo satellites have a resolution of about 2 cm (less than an inch). Meanwhile, the Americans have four improved KH-11 (sometimes called KH-12s) satellites in orbit, the last of these launched in 2013. The first of new KH-11s (sometimes called KH-13s) was launched in early 2019 and, like the KH-12s, will cost over $4 billion each.
China describes its Gaofen photo satellites as being put into orbit for largely non-military uses and to reduce Chinese dependence on commercial photo satellites for commercial services. That is largely true but what makes a photo satellite a military-grade photo reconnaissance satellite is a lot of additional features that rarely make it into official press releases. Since these satellites can be seen (in great detail) and photographed from the ground, it is easy enough to judge the exact purpose of photo satellites. That first Geofen looked a lot like American KH-11s put into service during the 1990s and has a mirror (lens) diameter of 1.7 meters. The four American currently KH-11s in orbit have 2.4 meter mirror diameter. That’s the same size as the mirror in the Hubble space telescope, which was turned on distant galaxies rather than the earth's surface.
In other respect, the Chinese were correct in saying they wanted to reduce their dependence on commercial photo satellites. In 2015 the American NGA (National Geospatial Intelligence Agency) admitted what everyone already suspected; that it gets most of its satellite photos from commercial satellites. This was no secret inside the military. That’s because, since the late 1990s, when commercial photo satellites began to show up, military users were quick to buy and use this unclassified data. The commercial photo satellites gradually caught up with their military counterparts, which first appeared in the 1960s, and got even more business from the military. What really got this movement going was the 2005 appearance of Google Earth (earth.google.com). This easy-to-use web-based app revolutionized military intelligence. The military didn't like to admit it at first. But Google Earth putting so much satellite photography at the disposal of so many people, in such an easy-to-use fashion, also made much more information available to military professionals (and terrorists, and criminals and academics as well). All of these military users quickly appreciated what a splendid new tool they had, just as many commercial firms also finding new uses for Google Earth data. And you couldn’t beat the price.
To the U.S. Department of Defense, Google Earth's major problem was not the ease-of-use, but the manner in which it showcased the shortcomings of the NGA, which was responsible for taking the satellite photos, spiffing them up as needed, and getting them to the troops. Trouble is, the stuff still wasn't getting to the troops that needed it when they needed it. This was made very obvious when Google Earth showed up and demonstrated how you can get satellite images to anyone, when they need them and do it with minimal hassle.
The NGA and other government agencies liked to keep all satellite (and aerial) images in classified archives, just in case they contained some secrets a potential enemy could use. Google Earth did great damage to this attitude. Changing minds in the military intelligence community isn’t easy. Restricted access to satellite photos is an old problem. Since the 1980s, when lots more satellite images became available, often on very short notice, generals and other officers with access to "satellite imagery" have been complaining about the difficulty they had in getting their hands on this stuff or passing it on to the officers and troops who need it most.
Hundreds of billions of dollars have been spent on photo satellites since the 1960s, and the troops always seemed to get leftovers, if anything and usually too late to be of any use. Yet the satellite people regularly conned Congress out of more money so they could build more satellites and neat systems that would get the satellite imagery "to the troops." The goods never arrived, or never arrived in time. Generals gave angry testimony before Congress about this non-performance after the 1991 Kuwait War. The satellite people seemed contrite and said they would make it right. If given the money to do it. They got the money and the troops got nothing.
Then the troops got access to Google Earth in 2005 and saw firsthand what they have been missing. To make matters worse the software Google Earth uses to get the job done was first developed for the NGA. But the way the NGA operates you had to worry about security considerations and all manner of bureaucratic details before you could deploy a useful tool so they really couldn’t use the Google interface on a wide scale. Mention that the troops in question are fighting a war and the NGA will point out that you still have to deal with security and keeping the paperwork straight.
Soon after 2005, the troops were beating NGA over the head with Google Earth and Congress took notice. However, NGA bureaucrats were close at hand and the angry troops are far away. Progress was still slow. But at least the troops had Google Earth. Unfortunately, so did the enemy. Nevertheless, over the next decade, the army was able to go directly to commercial satellite photo providers who, every year, were putting up more capable photo satellites. Many of the photos from these new satellites were higher resolution and not available on Google Earth. But the army could afford to buy them (as could other commercial customers) and give the troops instant access because all these commercial satellite photos were unclassified.
After a while, NGA stopped pouting and got on board with the use of lots of unclassified satellite photos. This also spurred the NGA to make the high quality (high resolution and with other enhancements) spy satellite photos more easily available to the troops, or at least the army intel and planning specialists who worked out the details of how battles would be fought. This led to other intel agencies making their data (especially from electronic data collection satellites) available quickly (often in real-time) to the troops who needed it.
Google Earth was also very popular with the growing Internet population in China but Google was forced out of China in 2009. That was over control and censorship issues. The Chinese government noted quite a lot of popular anger over the loss of Google, especially Google Earth. So in 2010 China introduced its own version of Google earth called Tianditu (Map World). It was a much diminished version of Google Earth and photos of China and North Korea showed much less and were not as up-to-date as Google Earth. Tianditu showed a much less censored view of the rest of the world, but not to the extent of Google Earth. Gaofen is expected to upgrade the frequency and quality of Tianditu images, but will still not be as popular as Google Earth.
While Google Earth opened the floodgates and gave the troops instant access, what happened first was the availability of high-resolution satellite photos that could be of use to combat forces. This began in the 1960s with the first appearance of the KH (Key Hole) series of photo satellites. The first film camera satellite, KH 1, went up in 1959 but the first successful one was in 1960. Thus until the 1970s, the film-using satellites supplied coverage of hostile nations. The KH 1 through 9 series satellites sent the film back in canisters so these high-resolution pictures could be developed. The Keyhole 9, the first of which went up in 1971, was not only the last of the film satellites but the largest and most capable. Its basic design was used by the subsequent digital camera birds. The KH 9 could cover large areas at high (for the time) resolution of .6 meters (24 inches). This was more than adequate to spot and count tanks, aircraft, and even small warships. The 19th, and last, KH 9 went up in 1984. The KH-9 was a 13 ton satellite with multiple cameras and 4 or 5 reentry vehicles for returning the film for developing and analysis. The KH-9s were nicknamed Big Bird.
The age of film began to fade when the first digital satellite, the KH 11, was launched in 1976. These birds were large, nearly 15 tons, and the digital cameras could obtain better resolution and broadcast the photos back to earth. The resolution was such that objects 70mm (a few inches) in size could be identified from 200 kilometers. Digital cameras were more flexible than film and eventually surpassed film in all categories. The KH-11 telescopic cameras operated like a high-resolution TV camera. Images were captured continuously and transmitted to earth stations. Computers were used to finish the process and produce photos identical to those taken by a conventional film camera. You could even have motion pictures, as well as indications of heat and the nature of the various items. KH-11 could often tell what kind of metal an object on the ground was made of.
All this did not come cheap. These birds cost over $400 million each and lasted three or four years, depending on fuel usage. Moreover, you needed two of them up at the same time in order to guarantee coverage and save the birds from having to change orbit too frequently. The most recent KH-11, the 15th, was launched in 2013. There have been at least four models of the KH-11 since the first of five "Block 1s" was launched in 1976. Since the 1960s over a hundred KH series satellites have been launched. The Big Bird film using KH-9s didn’t last long because once their film supply was gone they were useless.
The next generation of digital satellites, the KH-12 (officially “improved KH-11”), was supposed to have been launched in 1987. But because of problems with the space shuttle (one had exploded during launch), only a belated KH-11 was launched in October 1987. The KH-12 was delayed, even though it had several advantages over the KH-11. Along with improvements in ground data processing equipment, the KH-12 could send back data in real-time. You could watch events on a large, high-resolution screen as they were happening. This would also allow military headquarters and other users to get their satellite information directly, without going through a CIA or NRO (National Reconnaissance Office) processing center. Data from the more esoteric sensors would still have to be studied by the specialists elsewhere. The KH-12 was expected to make users even more enthusiastic about satellite reconnaissance. It did, in the form of a much upgraded KH-11. Actually, these birds were called KH-12s but are still officially known as KH-11 and still are. That is something of a tribute to the capability and flexibility of the original KH-11 design, the first of which went into orbit during 1976.
The flood of photographic and electronic data was growing far larger than the force of analysts available to make something of it. In addition to the KH series birds, there were radar and SIGINT (Signal Intelligence) satellites constantly broadcasting data. Then there are the Defense Support Program satellites, which use heat sensors to locate the hot plumes of missile launches. So although no new KH-11s have been launched since 2013 there have been plenty of new spy satellites put into orbit, especially radar satellites for monitoring the earth's surface in any kind of weather.
It has long been suggested that the government just rely on commercial photo satellites for their low resolution (able to detect vehicles and buildings) photo satellite needs. But the military and intelligence agencies often need more photo satellite time than the commercial companies can provide. The government also wants to ensure secrets are kept by having complete control over at least a pair of commercial-grade satellites.
The two new government-owned commercial birds took over the task of tracking troop movements, bases, and military operations in general. The two new high resolution, military-grade, spy satellites were improved versions of existing ones. These are used to get detailed (able to detect something smaller than an inch) photos of something the commercial-grade images (able to detect something 30-45 cm/12-18 inches in size) found interesting.
The troops and military planners are also big users of Google Earth, which annoys the people running the military satellite program. But for many military satellite needs, Google Earth does the job. The two military, commercial-grade, photo satellites eliminated the potential for information leaks (about what the military is buying images of) and provide much more capacity to do low-resolution jobs.