th launch of its own version of the U.S. Air Force X-37B UOV (unmanned orbital vehicle). The Chinese spaceplane landed two days later on a 5,000-meter (16,000 foot) landing strip near their Lop Nor nuclear test site in the Gobi Desert. No pictures of their UOV have been released yet and when asked what their UOV was like the Chinese mentioned the X-37B. The Chinese UOV was spotted by an American space surveillance system releasing a smaller object into orbit. The Chinese UOV apparently released two such objects before returning to earth. The Chinese UOV remained in a 350 kilometer high orbit for over 40 hours.
China reported the September 4
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. The 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 1988 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 months) mission. The X-37B has been doing this for 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 and September 2017) kept the X-37B in orbit longer (225 days then 469, 675, 718 and 780). There are two X-37B spaceplanes so they are not putting the same one back into orbit soon after it returns.
One unanswered question is; what does X-37B or the Chinese UOV do up there? The X-37B operations are classified secret and little information about what happens in orbit is released. China seems to be equally secretive. The most recent X-37B mission caused a problem when the air force mentioned that the X-37B had carried and released three cubesats (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 during their two days in orbit. The latest X-37B in orbit was reported to be carrying more items to put into orbit than any previous X-37B.
Cubesats are technically U Class spacecraft that can be no larger than 10 cm (about four inches) square and weigh no more than 1.33 kg (2.9 pounds). 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. Over 1,200 cubesats have been launched since 1998, with about 93 percent reaching orbit. That number is expected to double in the next few years because more and more commercial satellite launchers are providing unused space and weight on their launcher rockets for carrying and launching some cubesats. 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. is 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 has 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. Mission 5 was apparently similar to Mission 4 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 was originally scheduled for late 2019, using the disposable Atlas 5 launch vehicle normally employed but probably on its way out. SpaceX is cheaper and has a growing list of successful landings including twelve successes in a row, including all ten in 2017. The SpaceX landing tests began in 2010.
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 (280 days). The real endurance appears to be 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-37B has been doing up there for nearly 2,000 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 (500-660 pounds). The payload bay is 2.1x1.4 meters (7x4 feet). 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 (14 feet). In contrast, the Space Shuttle was 56 meters long, weighed 2,000 tons and had a payload of 24 tons.
The X-37B is a classified project, so not many additional details were expected to be made available. It's 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 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 constantly switch positions, 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 the 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.