In a hypersonic race for rapid-fire satellite-launching supremacy, China and the US are unveiling dueling futuristic technologies that could be crucial in a war scenario where satellites are targeted.
The South China Morning Post (SCMP) reported this month that China plans to build a giant railgun to launch its Tengyun spaceplane, combining electromagnetic launch and hypersonic flight.
China aims to use a giant electromagnetic launch track to accelerate a hypersonic aircraft to Mach 1.6, separate from the track, ignite its engine and enter near space at seven times the speed of sound, the SCMP report said.
The Tengyun spaceplane is designed to carry crew and cargo into orbit and release satellites into space. It may also be designed to conduct other missions including docking with or capturing satellites or surveillance.
SCMP says the Tengyun project presents a viable application of electromagnetic launch technology to overcome challenges in high-speed flight efficiency.
China Aerospace Science and Industry Corporation (CASIC) has constructed a two-kilometer low-vacuum track high-speed maglev test facility in Datong, Shanxi province.
The facility can propel a heavy object to speeds approaching 1,000 kilometers per hour, according to the SCMP report. The length of the test line will be extended to achieve a maximum operating speed of 5,000 kilometers per hour in the coming years, the report said.
At the same time, US-based Stratolaunch’s Talon-A (TA-1) hypersonic vehicle recently made its first powered flight carrying multiple test payloads off California’s coast, The Warzone reported this month.
The wedge-shaped unmanned aircraft, launched from the company’s massive Roc jet, achieved around 200 seconds of powered flight, reaching supersonic speeds approaching Mach 5, the Warzone report said, adding it is expected eventually to reach Mach 6.
The report notes that Stratolaunch has since 2018 focused on hypersonic development support instead of its original focus on space launches. It mentions the company is considering introducing a fueling top-off capability to enhance TA-1’s performance.
The TA-1’s first powered flight serves to continue risk reduction for the first reusable flight of the company’s second prototype, designated TA-2.
TA-1 and TA-2, which the US Missile Defense Agency may use as threat-representative targets for hypersonic threat engagement and interception, are both fully reusable and feature tricycle landing gear for recovery.
While TA-1’s stated purpose is to be a practice target for hypersonic missile defense, its design elements and testing data could be instrumental in developing Stratolaunch’s Black Ice spaceplane, which is envisioned to have advanced on-orbit cargo return and cargo launch capabilities.
Meanwhile, China’s spaceplane railgun launch system is similar in concept to the Electromagnetic Aircraft Launch System (EMALS) on its Fujian aircraft carrier and the US Gerald Ford-class supercarriers.
In contrast to traditional steam catapults, EMALS uses a linear induction motor to propel aircraft off the flight deck. EMALS also enables the launch of heavier aircraft in a shorter period while being gentler on airframes.
However, in the 2017 Proceedings of the SARC-ACN International Conference, Azeem Sigh Kahlon and other writers point out that one EMALS launch can consume 100 megawatts of energy, enough to power a small town.
Kahlon and others say a conventionally powered ship needs more steam boilers to provide that energy, which would take up space for other vital equipment. They also point out the low thermal efficiency of naval nuclear reactors, as they are required to generate flexible power, in contrast to land-based reactors’ steady maximum power output.
While China’s Fujian carrier is the only one outside the US Navy to possess EMALS technology, it may be limited by the ship’s conventional power source compared to US nuclear-powered supercarriers.
However, placing EMALS technology on land may remove some power constraints associated with conventional shipboard power and enable it to launch heavier loads that require more power such as spaceplanes.
The Ukraine war has validated the strategic importance of satellite constellations, incentivizing the US and China to research cost-effective methods of deploying multiple satellites quickly.
The capability to promptly launch large numbers of satellites is essential to providing space-based communications, intelligence, surveillance, reconnaissance, targeting and redundancy.
In line with that, Sam Bresnick notes in an August 2023 Breaking Defense article that China may already have exceeded the US in tactically responsive space launch (TRSL), the capability to quickly replace damaged or destroyed satellites in the event of a conflict.
Bresnick notes that the US space industry has focused on payload capacity, reliability and efficiency as well as launching as many satellites as possible.
He points out that this has led to the development of large, liquid-fuel rockets that take significant time to launch, requiring complex positioning and fueling processes and sophisticated ground support equipment.
In contrast, Bresnick notes that while China has similar liquid-fuel rockets, it has focused instead on developing mobile, solid-fuel rockets that do not need complex launch infrastructure.
Bresnick says that these smaller rockets, while incapable of carrying as many satellites as liquid-fuel ones, can be launched from remote locations, making them ideal for replacing damaged or destroyed satellites.
China’s railgun-launched Tengyun may further strengthen its TRSL capabilities, although it may face stiff competition from US reusable rockets.
In terms of costs, Chris Daehnick and other writers note in an April 2023 McKinsey & Company article that reusable launch technologies such as SpaceX’s Falcon 9 and Falcon Heavy rockets have brought down the cost of putting payloads into orbit from US$65,000 per kilogram to around $1,000.
Significantly, China has yet to demonstrate reusable rocket technology. This month, Space News reported that China Aerospace Science and Technology Corporation (CASC) plans to launch reusable rockets in 2025 and 2026.
Daehnick and others point out the historical lag between first flight and peak launch rate, which is five to nine years for medium and heavy-lift vehicles.
That lag may be more pronounced in prototype spaceplanes, although they point out that historical experience may be less relevant as new manufacturing technologies and approaches are deployed.
While reusable rocket technology is relatively mature, spaceplane technology is still at the testing stage, which can make the former a more established and feasible launch option in the near term.