China Tests Proximity Operations with Experimental Spaceplane

China's experimental reusable spaceplane has taken another significant step in advancing its capabilities by conducting a series of proximity operations with a smaller spacecraft, potentially even capturing the object.

The spaceplane's latest mission, which marks its third launch, was carried out using a Long March 2F rocket on December 14, 2023. On May 24, 2024, U.S. Space Force space domain awareness teams cataloged an object released by the spaceplane into orbit. This object, referred to as "Object G," had been in stable operation after undergoing an orbit-raising maneuver.

Observations and analysis from Marco Langbroek, a lecturer in optical Space Situational Awareness at Delft Technical University in Leiden, the Netherlands, suggest that the spaceplane used Object G to test rendezvous and proximity operations (RPO) on June 7-8, 2024. According to Langbroek, these operations could have a dual purpose: they might be used for the retrieval, repair, and maintenance of friendly satellites or potentially for counterspace operations against adversarial spacecraft.

"Some combinations of the orbital data for epoch 24160 do suggest that a potential very close approach at kilometer level or even less might have happened on 8 June near 14-15h UTC," - Marco Langbroek

After deploying Object G, the spaceplane executed an avoidance maneuver and conducted additional maneuvers between June 5-7, 2024, bringing it close to the object again on June 8. The close approach between the spaceplane and Object G indicates intentional proximity operations, though it remains unclear whether the spaceplane briefly retrieved and re-released the object.

This is not the first instance of such activities by China's spaceplane. Data from the private firm Leolabs indicated that during its second mission in 2022-2023, the spaceplane performed at least two and possibly three capture/docking operations with a co-orbiting object. Additionally, China has conducted RPOs in geostationary orbit, including the Shijian-21 mission, which towed a defunct satellite to a high graveyard orbit in December 2021.

Such operations in the GEO belt are significant due to the counterspace activities involving major spacefaring nations like the United States, Russia, and China. The U.S. military has been enhancing its capabilities to detect and track potential threats in GEO.

China has maintained a high level of secrecy around its spaceplane project. The country's space authorities have not released images or detailed descriptions of the spacecraft, with the only official report being a brief announcement following the launch.

"During this period, reusable technology verification and space science experiments will be carried out as planned to provide technical support for the peaceful use of space," - China

The Chinese reusable spaceplane, which draws comparisons to the U.S. Space Force's X-37B, represents a significant advancement in space technology by potentially reducing costs and increasing the frequency of missions. The first flight of China's spaceplane in 2020 lasted two days, while the second mission extended to 276 days. Both missions involved the deployment of an object in orbit. The interval between the first and second missions was nearly two years, with the third mission following a seven-month gap.

The spaceplane is designed to work alongside a reusable suborbital first stage, which employs vertical takeoff and horizontal landing. This suborbital craft was first tested in 2021, with a second mission conducted in August 2022. The China Aerospace Science and Technology Corporation (CASC), the developer of the spacecraft, has announced plans for a fully reusable, two-stage-to-orbit (TSTO) space transportation system. In 2022, the spaceplane project received national funding from the Natural Science Foundation of China.

Meanwhile, the U.S. Space Force's X-37B spaceplane embarked on its seventh mission on December 28 of the previous year. Launched for the first time on a Falcon Heavy rocket, the X-37B was sent to a highly elliptical, high-inclination orbit at a greater altitude than its previous missions. The X-37B, an autonomous and reusable vehicle, has been operational since 2010.

As China continues to develop and test its reusable spaceplane capabilities, the advancements highlight the growing competition and strategic importance of space technology in global geopolitics.