In December 2023, China launched its Shenlong (Divine Dragon) military spaceplane. The craft was designed by the China Academy of Launch Vehicle Technology (CALT). China had previously tested experimental orbital spaceplanes in September 2020 (lasting two days) and August 2022 (which lasted 276 days). The current mission is still in progress.
Last December, the spaceplane was launched from the Jiuquan Satellite Launch Center in China’s Gobi Desert atop a Long March 2B rocket. The China Aerospace Science and Technology Corporation (CASC) news release stated the test would verify reusable technology and carry out space science experiments. During this third test, Shenlong released six unidentified objects into Earth’s orbit.
Chinese media had previously identified applications for the Shenlong such as astronaut transport, space station resupply, space tourism, and satellite deployment. According to Chinese space scientists, reusable spaceplanes are a key component of a major space power. The development of China’s military spaceplanes, the release of objects in the latest test, and the secretive nature of what these spaceplanes carry inside have major strategic implications.
The Strategic Advantages of a Reusable Spaceplane
Having inexpensive and reusable space access carries major national security implications. Reusability enables an entirely different and faster tempo of operations, making one less predictable. A high tempo of reusability enables a scale of operations sufficient to challenge an adversary in multiple orbits, and a scale of operations to shape the battlespace to one’s advantage.
The potential of high-tempo reusability need not even involve achieving orbit to be game-changing. For example, a spaceplane can execute a “once-around” maneuver, flying a partial orbit or even a sub-orbital trajectory. This is a huge advantage because while space provides phenomenal vantage for reconnaissance and legal overflight, once a satellite has completed a few orbits, both its orbit and capabilities are characterized sufficiently to know when to hide from its sensors – but employed in a once-around trajectory, tactical surprise reconnaissance is possible. This enables rapid, unpredictable transit over an adversary state (not unlike the Cold War era SR-71 spy plane), but legally in outer space and above their sovereign airspace.
Nor is reconnaissance the only employment concept for “once-around” operations, as a spaceplane can carry more than just cameras. Since the earliest spaceplane concepts, it has always been apparent that a potential mission might be bombardment. Because an adversary may be conditioned to “normal” spaceplane operations; unlike a missile launch, an adversary would not know if a particular spaceplane mission was a threat until it opened its doors. This would greatly reduce the time to react. Spaceplanes could therefore be used as a novel first-strike weapon for a surprise attack.
Thus, a spaceplane not only threatens an adversary’s national security by reducing the adversary’s ability to hide or avoid espionage, but it also presents an implied threat that must be constantly monitored.
The flexibility of a spaceplane introduces deliberate uncertainty about what its capabilities and cargo are. As recently demonstrated, Shenlong can release multiple small satellites, and, not unlike the Chinese balloon incident, these microsatellites are “cost imposing” on the United States, which must then figure out the signals and purpose of the devices.
The operational flexibility and its implications may not at first be obvious, but it is the result of three factors: the spaceplane is a complete spacecraft with a proven ability to navigate, communicate, and maneuver; the spaceplane has a general-purpose payload bay with standard connections and doors that can open or remain closed; the spaceplane can return (with its cargo) to Earth.
The fact that the spaceplane’s cargo compartment is general purpose and behind closed doors means you don’t know what you might face. The fact that the vehicle can maneuver means it can threaten multiple assets you value. The combination means you could be surprised. Either way, it is going to make you nervous.
Thus, a spaceplane can conceal, wait for the right moment, and deploy a variety of small satellites to LEO, which might include imaging and electromagnetic mapping for targeting, missile warning, space domain awareness, or global navigation satellite systems or satellite communication – whatever the tactical situation might demand. It also might contain counterspace co-orbital attack satellites. In principle, it might even contain kinetic kill vehicles for missile defense or launch denial to block a rival’s access to space, or even space-to-ground kinetic strike munitions. The adversary would not know in advance what is inside, and so the attacker might achieve tactical surprise.
But because a spaceplane is a complete spacecraft with the ability to host payloads, it also means that the spaceplane could host a great variety of onboard capabilities, including sensors, radio transmitters, robotic servicing equipment, and even counterspace weapons (jammers, dazzlers, projectile weapons, directed energy weapons, robot arms), all of which the spaceplane can maneuver to a target, whether that target is in space or on the ground. The flexibility to rapidly integrate and trade out payloads enables tactical response. There is no need to build an entirely new spacecraft – just put the specific payload you need on board and fly.
In the typical military measure-countermeasure game, fixed satellites in orbit cannot be upgraded as adversaries develop counters. But a spaceplane allows one party to rapidly upgrade their technology with their own counter, and the adversary would not even know what they are facing until the spaceplane opens its payload bay doors. Moreover, unlike most satellites, spaceplanes can accomplish close-in maneuvering to dock and perform service (or mischief), and since there are as yet no standards for safe distance (legal or otherwise), a spaceplane could get uncomfortably close.
This also results in the greatest near-term benefit of experimental spaceplanes: they enable a much faster tempo of experimentation and development of new components by exposing them directly to the actual space environment and getting them back to make improvements – before committing to launch them permanently on a satellite or constellation of satellites. Because the spaceplane provides all the housekeeping, and also returns the payload, a spaceplane offers the ability to test all manner of spacecraft components as payloads (sensors, antennas, computers, navigation systems, robotic arms). It also enables China to test and mature concepts for in-space servicing, assembly, and maintenance.
A final advantage is that spaceplanes can both be stationed in orbit for extended periods, can maneuver, and can be recalled. This creates a mechanism to signal seriousness and intent, which can be used both to escalate (by launching and prepositioning) and de-escalate (by de-positioning and deorbiting).
A nation might, for example, signal its seriousness, by placing several loaded spaceplanes into key orbits, carrying payloads or small satellites that might augment, replace, or attack, but keeping them inside the payload bay doors. If the conflict escalates, that nation is in a position to deploy them. If the conflict de-escalates, the nation can show good faith by returning the spaceplanes to Earth – with the added benefit that the satellite spares can be upgraded, serviced, or reconfigured for subsequent challenges. Thus, spaceplanes create new potential for signaling, distraction, and deception.
The Shenlong and Beyond: China’s Spaceplane and Related Programs
It is important to remember that the concepts demonstrated and technology developed on the Shenlong are just the beginning. While the Shenlong has rocket engines to help it achieve orbit and maneuver in orbit, indications are that, like the Space Shuttle, it functions as an unpowered glider for landing, and requires a traditional booster rocket to achieve orbit. But for decades there have been more advanced concepts, such as a hypersonic air-breathing first stage, a combined cycle air-breathing/rocket spaceplane (capable of maneuver on ascent and descent), and even a single-stage-to-orbit spaceplane that could takeoff right from a runway fly to orbit and return, or alternately take off and land vertically like Starship. China appears to be seeking to advance all these concepts.
CASC’s Shenlong is hardly the only Chinese spaceplane initiative. The China Aerospace Science and Industry Corporation (CASIC) is developing a concept called Tengyun (Cloud Rider) where a Shenlong-similar spaceplane is launched from an air-breathing first stage; CASIC has released a video of the Tengyun. China showcased a similar concept test article in what it claims is the fastest wind tunnel, capable of Mach 30, reportedly powered by a detonation-wave engine.
In theory, because an air-breathing first stage only has to carry its fuel and not its oxidizer like a rocket, this might allow smaller first stages, potentially allowing a spaceplane to use the thousands of existing runways. This would require less custom infrastructure and allow for better integration with aviation operations, thus enhancing tempo, operational flexibility and the potential for operational surprise.
CASIC is also working on a commercial spaceplane, to be launched by 2030. CASC has released a concept for a reusable “Mars express” spaceplane for regular transit from Earth to Mars and back.
Closer to Earth, China has also recently created a hypersonic “near-space” command “for precise and merciless attacks.” Near space is defined as “the region of Earth’s atmosphere that lies between 20 and 100 kilometers above sea level, encompassing the stratosphere, mesosphere and lower thermosphere – altitudes above the upper limit for commercial airliners but below orbiting satellites.” China has already demonstrated its willingness to violate the sovereign airspace of multiple nations with its balloon reconnaissance.
In terms of developing these systems, returning the upper stage of a reusable system is a key technical challenge. A spaceplane must endure extreme thermal and pressure loads, which stress materials, thermal protection, and aerodynamic maneuvering systems. Another key challenge is to keep the cost and time to refurbish and relaunch such a system to a minimum. Testing helps understand and overcome these challenges, bringing China one step closer to an operational fully reusable system.
Moreover, it turns out that the same challenges key to a reusable space plane – surviving atmospheric reentry and maneuvering at hypersonic speeds – are also the challenges faced in the development of boost-glide hypersonic missiles, fractional orbital bombardment systems (FOBS), space-to-Earth kinetic strike weapons, suborbital point-to-point rocket cargo, and space-to-Earth delivery, as well as trans-atmospheric vehicles (TAVs) and near-space hypersonic vehicles. Thus, a spaceplane program can be used to develop or cloak the covert development of a variety of high-end weapons systems. Certainly, the data and experience gained by testing a spaceplane will simultaneously advance China’s hypersonic missile program and reduce the technical barriers for space-to-Earth attack.
To support its space and near-space aims, China is making significant investments in supporting technologies including hypersonic engines – and it appears that four or five of China’s state-owned industries are working on hypersonic-related products. China has claimed both to have developed a low-cost hypersonic engine capable of mass production that can achieve Mach 5, and to have created an entirely new rotating detonation air-breathing hypersonic engine capable of pushing vehicles to Mach 16, or 16 times the speed of sound. That’s a little more than half the speed required to get to orbit, and fast enough to reach any point on Earth in under two hours.
Over time, and with lots of testing, China may succeed in bringing these multiple lines together into a much more capable operational spaceplane, capable of both transatmospheric “near-space” operations and orbital operations. For example, CALT has released concept video for point-to-point transportation systems featuring both a Starship-like concept and an air-breathing hypersonic spaceplane. CALT also tested a powered reusable suborbital spaceplane in inner Mongolia in both July and August.
The Shenlong, as an experimental spaceplane, will provide the necessary test data to build more advanced prototypes or an operational system. Even as an experimental spaceplane, it will accelerate China’s ability to test spacecraft components and harass other space powers. Perhaps most importantly, the Shenlong is likely to provide China with the operational experience, techniques, and tactics that are a necessary precursor to a useful fielded system and operational unit. It is a development that other spacefaring nations ignore at their peril.