A Long March 2D launch vehicle placed two Shiyan-30 satellites into orbit from Xichang. Official mission: observation tests. Orbit at 590 km, inclination 35°. Technical analysis and challenges.
Summary
A Long March 2D took off from the Xichang Satellite Launch Center at 03:00 UTC (11:00 Beijing time) and placed two Shiyan-30 satellites (01) and (02) into low orbit. The operator, China Aerospace Science and Technology Corporation, announced a “terrestrial observation experiment” mission, without providing any details or imagery. The objects were catalogued in a quasi-circular orbit at an altitude of approximately 590 km (35° inclination). The Shiyan series serves as a flight test bed for optical and radar sensors, communications links, onboard processing, and sometimes rendezvous and proximity operations. The exact payload remains unknown. In the background, China is conducting a series of orbital launches in 2025 and strengthening its industrial base, from the Long March 2D hypergolic launcher to the SAST integrator. Possible applications include observation, electronic intelligence, space surveillance, and the validation of swarm architectures. The strategic signal is clear: acceleration of dual capabilities.
Highlights of the launch
The flight took place on September 29, 2025, at 03:00 UTC, or 11:00 a.m. in Beijing, from Xichang. The mission carried Shiyan-30 (01) and Shiyan-30 (02), officially designated by CASC as “experimental” satellites focused on observation. Public information is minimal, a recurring feature of Shiyan flights. In terms of orbital dynamics, the two objects were identified in a quasi-circular orbit at an altitude of approximately 590 km (apogee 598 km, perigee 592 km) and 35° inclination, with a period of approximately 96.4 minutes. These parameters favor rapid revisits at low and medium latitudes, which are useful for sensor and communications testing.
The launch vehicle and infrastructure
The Long March 2D is a reliable two-stage hypergolic (N₂O₄/UDMH) launcher, rated at approximately 3.5 t in low orbit and 1.3 t in SSO at 700 km. It has been flying since 1992 and recently celebrated its 100th successful launch, making it an ideal “tractor” for experimental payloads. The launch took place from the LC-3 complex in Xichang, an inland site surrounded by mountains, historically oriented towards low to medium orbital planes. The simplicity of the 2D’s implementation and its low cost allow for frequent and discreet campaigns, in line with modest payloads and opportunistic launch windows.
The Shiyan program: a continuous demonstrator
Shiyan (“trial”) is a family of experimental satellites with a dual purpose. Official communiqués refer to “technology verification” or “space environment detection.” In reality, the series has been used to test a variety of components: high-resolution optics, multispectral sensors, data links, secure communications, autonomous navigation, and rendezvous and proximity operation capabilities. The granularity of the designations (SY-xx A/B/C) often reflects sub-series or additional payloads carried by the same rocket. The low volume of public images fuels analytical caution, but the recurrence of orbital profiles and the industrial relationship with SAST reinforce the hypothesis of targeted and iterative demonstrations.
Official objectives and likely uses
The brief description provided by CASC for these Shiyan-30s refers to “earth observation” tests. In the past, other Shiyan satellites have been associated with declared civilian uses: mapping, urban planning, disaster prevention and management, air quality, and crop monitoring. Technically, the 590 km altitude range is compatible with medium-field optical sensors and metric to decimeter resolutions depending on diameter and optical quality. It is also suitable for testing onboard compression/sorting algorithms—a priority for reducing ground throughput—and radio frequency payloads for signal collection or electronic intelligence in the civilian band.
Orbital parameters, a mission indicator
A 35° inclination orbit favors low and medium latitudes, with regular passes over Asia, North Africa, and the Middle East. At 590 km, the natural orbital lifetime exceeds several years, except for end-of-life maneuvers. The period of close to 96 minutes allows for multiple daily revisits in constellation or phased duo. For inter-satellite link testing, this altitude offers a compromise between mutual visibility and maneuvering cost. It is also suitable for demonstrations of space domain awareness in low orbit: location of nearby objects, photometric characterization, and evaluation of avoidance algorithms. Published TLE databases confirm the circular nature of the orbit, which is typical for repeatable measurement campaigns.
Possible military applications
The dual component is credible. On the one hand, imaging and remote sensing are used in agriculture, urban planning, and natural hazards. On the other hand, identical building blocks feed military functions: targeting, map updating, coastal surveillance, and space surveillance (SSA). Open literature attests to repeated Chinese tests in rendezvous and proximity, a key skill for object inspection, assistance, and even counter-space actions. Radio payloads can also capture ground or sea emissions for GEOINT/ELINT. Shiyan’s modularity allows these capabilities to be assembled in short iterations until they reach operational maturity and integration into dedicated constellations.
The industrial background and the role of SAST
The Shiyan-30 (01/02) are attributed to the Shanghai Academy of Spaceflight Technology, a major subsidiary of CASC. SAST has expertise in both platforms (buses) and payloads, and also produces launchers from the Long March family. This vertical integration facilitates rapid cycles: ground qualification, opportunistic launch on 2D, and iterations in orbit. In 2025, China’s pace is high, driven by state and commercial programs; in this flow, Shiyan remains a practical test vehicle for injecting technologies into operational lines, particularly for observation and in-orbit services.
The geostrategic impact
For Beijing, the value is not only technical. Each Shiyan flight maintains a controlled information fog: the adversary sees the orbit, not the payload. This ambiguity confers a strategic advantage, fuels technological attrition, and complicates the attribution of functions. In the context of space competition, repeated demonstrations in LEO fuel the credibility of distributed, loss-tolerant architectures that are resilient to anti-satellite threats. Partners and competitors interpret these signals through the prism of their own space domain awareness: the more dual-use components China validates, the more it expands its room for maneuver in orbit and on the ground.
Technical performance and limitations
The Long March 2D, with its hypergolic propulsion, offers flexible launch windows and relatively simple preparation, at the cost of toxic propellants. On the mission side, a 590 km orbit requires a compromise: good resolution for optics and a wide field of view, but higher fuel costs than lower altitudes for possible active maneuvers. The mass available for dual launches is limited, which encourages compact platforms, moderate-diameter telescopes, efficient data links, and advanced onboard processing to reduce the volume downloaded. Rendezvous and proximity tests in LEO also require accurate navigation sensors (stars, LIDAR, vision) and responsive attitude control; such subsystems have already been seen on other Chinese demonstration series.
The 2025 dynamic: an accelerating pace
The year 2025 is marked by an increase in the pace of Chinese launches. Already in the spring, several analyses noted an increase in the number of launches and payloads put into orbit compared to 2024. At the end of September, the phrase “intensified pace” reappeared in the trade press, and the Shiyan-30 launch clearly fits into this sequence. This pace fuels industrial learning, dilutes fixed costs, and multiplies opportunities to quickly “inject” technologies into orbit before transferring them to operational constellations.
What to watch for
The Shiyan-30 duo (01/02) could remain discreet for months. Indicators to watch for include possible altitude/phasing maneuvers, detected radio emissions, attitude variations revealed by photometry, and, above all, the appearance of companion objects. If rendezvous are initiated, they will signal advanced navigation and autonomy tests. Otherwise, regular revisit patterns will point more toward observation or listening payloads. In either case, each orbital evolution will offer valuable clues about the real purpose—and will reveal the pace at which China is transforming its demonstrators into deployed capabilities.
War Wings Daily is an independant magazine.