January 10, 2024: At the end of 2023, on December 14th, The Chinese Space Plane, called Shenlong (Divine Dragon) began its third orbital mission. There is no indication how long the Chinese spacecraft will remain in orbit. In August 2022 the Chinese Space Plane completed its second successful mission after remaining in orbit for 276 days. The first flight took place in early September 2020 and was in orbit for only two days. Initially China delayed releasing any photos of their reusable test spacecraft. Eventually there were satellite photos of the Chinese space plane after landing that showed a space plane similar in size to the American X-37B. The second launch and orbital activity was more closely observed. China delayed releasing any photos of its space launch facility, known as CSSHQ. The Chinese designer revealed that Shenlong is expected to be useful for up to 20 launches.

The Chinese version of the U.S. Air Force X-37B UOV (Unmanned Orbital Vehicle) lands at a 5,000-meter landing strip near their Lop Nor nuclear test site in the Gobi Desert. The Chinese mentioned the X-37B when they first announced their effort in 2017. During its first flight, the Chinese UOV was spotted by an American space surveillance system releasing a smaller object into orbit. The Chinese UOV apparently released two smaller objects before returning to earth. The Chinese UOV remained in a 350-kilometer-high orbit for over 40 hours on its first flight and is using a similar orbit during its second mission. The third, and current, mission uses a similar orbit and circles the earth once every 90 minutes.

The Chinese UOV was not a complete surprise as Chinese space officials mentioned such a project in 2017. It was believed they would test their UOV in 2020 and they did, but without any publicity until it landed safely. The only other nation to develop and use a spaceplane was Russia. Their Buran project was similar to the American manned Space Shuttle and made one unmanned flight in 1988. This was for only two orbits before Buran was landed. The Soviet Union dissolved in 19991 and there was no money for further work on Buran. The one working Buran vehicle was stored in a hanger and destroyed in 2002 when the hanger collapsed. The European Space Program is developing a space plane as is India.

On May 17, 2020, one of the American X-37Bs was launched into orbit, the sixth time this has been done. This was seven months after the other X-37B returned from its last, and longest 25.5 month mission. The X-37B has been doing this for over a decade now, going into orbit for the first time in April 2010, and remaining up there for over seven months. Each subsequent launch (March 2011, December 2012, May 2016, September 2017, and May 2020) kept the X-37B in orbit longer (225 days then 469, 675, 718 and over 908). There are two X-37B space planes, so they are not putting the same one back into orbit soon after it returns. Mission six remained in orbit for 908 days. The seventh mission launch is supposed to happen by the end of 2023.

The X-37B was developed by NASA as the X-37A but in 2004 that project was turned over to DARPA the Defense Advanced Research Projects Agency. In 2006 the U.S. Air Force announced it was developing a larger X-37B and this replaced the DARPA X-37A project.

One unanswered question is what does X-37B or the Chinese UOV do up there? The X-37B operations are classified and little information about what happens in orbit is released. China has been equally secretive. On one X-37B mission the air force mentioned that the X-37B had carried and released three cubesats or very small satellites that were not registered with the UN. That X-37B was known to be carrying ten cubesats to be released into orbit to perform various experiments. The Chinese appear to have done the same while in orbit. The latest X-37B in orbit was reported to be carrying more items to put into orbit than any previous X-37B. The Chinese UOV released similar small satellites during its first flight, apparently to test the cargo launch system. Shenlong released several smaller objects during it latest flight. These objects appear to be broadcasting a signal that could be detected on earth.

Cubesats are technically U Class spacecraft that can be no larger than 10 cm square and weigh no more than 1.33 kg. Cubesats are increasingly popular for science experiments by smaller organizations, or even individuals, who cannot afford a multi-million-dollar satellite that is ten or more times larger and heavier than a cubesat. About 4,000 cubesats and similar Nanosats have been launched since 1998, with over 90 percent reaching orbit. That number is expected to keep increasing because more and more commercial satellite launchers are providing unused space and weight on their launcher rockets for carrying and launching some cubesats and the smaller Nanosats. In some cases, the cubesat owners pay for this service while in other cases some cubesats are taken up for free, as a public service.

The U.S. was accused of using the unregistered cubesats launched from the X-37B as a test of a new anti-satellite weapon. A cubesat placed in the proper orbit could intercept and destroy or disable a much larger satellite. Or so the theory goes. The U.S. Air Force had no comment although two senior air force officials did mention, in 2019, that there were some secret anti-satellite projects underway. An anti-satellite weapon that is kept secret is more effective when used because the enemy doesn’t know what to prepare for.

The X-37B is unmanned and operated by earth-based controllers. It does have automatic landing software that has been used several times without any problems. While the air force reports few details about the X-37B, it was difficult to hide the fact that mission 5 used a different launch vehicle, the SpaceX booster. This was important because the SpaceX rocket itself is reusable; its first stage returns to earth and lands upright for refurbishing and reuse. Air force officials noted that the SpaceX design is a fitting match for X-37B which was designed for multiple reuse and autonomous operation. The Chinese UOVs were designed for at least 20 missions each. X-37B Missions, 4 5 and 6 were apparently all similar in that new technologies were tested, and more micro-satellites were placed in orbit, including the unregistered cubesats, which are the smallest class of satellites.

Mission 6 in 2020, using the disposable Atlas 5 launch vehicle was the last time it was employed. The SpaceX launchers are cheaper and just as reliable.

It was eventually revealed that X-37B mission 4 tested a new thruster system for mobile satellites that needed to be tried out while in orbit. Also carried were dozens of different materials, possibly including some new spy satellite components to see what the harsh environment in orbit, especially radiation, can do. Such exposure can have unpredictable effects on materials and microelectronics after prolonged time in space.

Earlier missions were also successful. The third X-37B mission ended in October 2014 after nearly two years in orbit. The second mission landed on June 16th, 2012, after 15 months in orbit. The first mission ended on December 3rd, 2010, after seven months in orbit. The official endurance of the X-37B was originally about nine months or 280 days. The real endurance is 3-4 times that, at least. The long endurance is largely because the X-37B carries a sizable solar panel, which is deployed from the cargo bay, unfolded, and produces enough power to keep the X-37B up there for a long time. The air force has not made public much about what the X-37Bs has been doing up there for over a total of over 3,000 days so far.

In effect, the X-37B is a remotely controlled mini-Space Shuttle. The space vehicle, according to amateur astronomers (who like to watch spy satellites as well), appears to be going through some tests much of the time. The X-37B is believed to have a payload of about 227-300 kg. The payload bay is 2.1x1.4 meters. As it returned to earth, it is designed to land by itself after being ordered to use a specific landing area. The X-37B weighs five tons, is nine meters (29 feet) long and has a wingspan of 4 meters. In contrast, the Space Shuttle was 56 meters long, weighed 2,000 tons and had a payload of 24 tons.

The X-37B has been in development since 2000 but work was slowed down for a while because of lack of money. Whatever the X-37B is now doing up there has been convincing enough to get Congress to spend over a billion dollars on it. What makes the X-37B so useful is that it is very maneuverable, contains some internal sensors (as well as communications gear), and can carry mini-satellites, or additional sensors, in the payload bay. The X-37B is believed capable of serving as a platform for attacks on enemy satellites in wartime. Using a remotely controlled arm, the X-37B could refuel or repair other satellites. All this is speculative because, as a classified project, there is little confirmed information about its payload or mission, other than testing the system on its first mission. It is likely that future missions will involve intelligence work, and perhaps servicing existing spy satellites which must use up their fuel to change their orbits. For regular satellite refueling missions a larger X-37C would probably be used. This is a scaled-up X-37B that would have a much larger, probably over a ton payload. The X-37C could be quickly switched between cargo and passenger configurations. The X-37C would still be robotic and not require anyone onboard to control it. Work on the X-37C has apparently been halted because there are similar alternative designs that are closer to service.

The X-37B also demonstrated that it could not be easily tracked while in orbit. An international collection of amateur sky watchers proved remarkably adept at spotting orbital objects in the past, including classified ones like the X-37B. The amateur orbital observer community has concluded that one thing the X-37B tested was how well it could change orbits and stay hidden. In that respect, the X-37B was a resounding success. That's because these amateur observers are generally very good at tracking what's up there.

But the X-37B has proved elusive and sometimes became a frustrating challenge to amateur sky watchers. This is pleasing to American air force officials, who designed the X-37B to be elusive to terrestrial observation, and the dedicated and quite effective amateur satellite watchers gave the X-37B quite a workout. China apparently seeks to do the same.