Shenzhou-21 Astronauts Complete Third Spacewalk and Install Critical Debris Protection on Tiangong Space Station

The crew of China’s Shenzhou-21 mission successfully executed their third extravehicular activity (EVA) outside the Tiangong space station on April 16, 2026, marking a significant milestone in the structural reinforcement and long-term maintenance of the orbital laboratory. Astronauts Zhang Lu and Wu Fei spent approximately five and a half hours working in the vacuum of space, completing the installation of specialized debris-protection hardware and conducting a comprehensive external inspection of the station’s modules. Supported by crewmate Zhang Hongzhang from within the Tianhe core module, the team utilized the station’s sophisticated robotic arm and coordinated closely with ground control in Beijing to ensure the mission’s success. The China Manned Space Engineering Office (CMSEO) confirmed that the duo returned to the Wentian experiment module’s airlock at 1:36 p.m. Eastern (1736 UTC), concluding a mission that further solidifies China’s operational capabilities in low-Earth orbit (LEO).

Technical Objectives and the Growing Threat of Space Debris

The primary focus of this third EVA was the mitigation of risks posed by micrometeoroids and orbital debris (MMOD). As the population of defunct satellites and fragmented hardware in LEO continues to rise, the protection of inhabited space structures has become a paramount concern for all spacefaring nations. The Shenzhou-21 crew installed protective shields and reinforcement hardware designed to absorb the kinetic energy of high-velocity impacts, thereby safeguarding the pressurized hulls of the Wentian and Mengtian modules.

This task was not merely routine maintenance but a direct response to recent challenges faced by the Tiangong program. Previous inspections had revealed the vulnerability of external systems to the harsh orbital environment. During this EVA, Zhang Lu and Wu Fei also conducted a meticulous survey of external equipment, including solar array drive mechanisms, communication antennae, and scientific exposure platforms. By identifying minor abrasions or potential points of failure early, the CMSEO aims to extend the operational lifespan of Tiangong, which is currently envisioned to remain active for at least a decade.

The success of the mission relied heavily on the station’s large robotic arm. This seven-axis manipulator served as a mobile platform for the astronauts, allowing them to reach distant sections of the station’s exterior with high precision. The synergy between the human "taikonauts" and the robotic systems demonstrates the maturity of the Tiangong infrastructure, which has been permanently inhabited since the Shenzhou-14 mission in 2022.

A Record-Breaking Achievement for Zhang Lu

The April 16 spacewalk was particularly historic for Zhang Lu, who has now participated in seven EVAs throughout his career. This achievement sets a new record for the highest number of spacewalks performed by a single Chinese astronaut, surpassing previous benchmarks and establishing him as one of the most experienced orbital technicians in the world. Zhang’s expertise has been instrumental in the complex assembly and outfitting phases of Tiangong.

The Shenzhou-21 mission has been characterized by its high tempo of extravehicular activity. The first EVA of this increment took place in December 2025, followed by a second in March 2026. These earlier outings were critical for the initial assessment of the station’s exterior following a debris-strike incident involving the previous Shenzhou-20 spacecraft. Zhang Lu’s leadership during these high-stakes maneuvers has provided the CMSEO with invaluable data on the performance of the Feitian space suits and the physical demands of long-duration orbital work.

Mission Chronology and the Shenzhou-20 Debris Incident

To understand the current priorities of the Shenzhou-21 crew, it is necessary to look back at the events of late 2025. The Shenzhou-21 trio arrived at Tiangong on October 31, 2025, expecting a standard six-month rotation. However, the mission profile was complicated by a significant safety concern involving the Shenzhou-20 return capsule.

Shortly before the Shenzhou-20 crew was scheduled to depart, ground controllers identified damage to a viewport on their spacecraft, likely caused by a small piece of orbital debris. Out of an abundance of caution, the CMSEO decided to alter the return plan. The Shenzhou-20 crew eventually returned to Earth using the Shenzhou-21 spacecraft, which had just arrived. To maintain an emergency "lifeboat" capability on the station, China accelerated the launch of Shenzhou-22, which docked on November 25, 2025.

This logistical reshuffling has led to an unusual mission duration for the current crew. Because they arrived on Shenzhou-21 but will return on Shenzhou-22, the "on-orbit clock" for their return vehicle was effectively reset. Consequently, the CMSEO announced following the latest EVA that the Shenzhou-21 crew’s stay will be extended by approximately one month. They are now expected to remain aboard Tiangong until mid-to-late May 2026, marking one of the longest continuous stays for a Chinese crew to date.

Scientific Research and National Celebrations

While the spacewalks capture public attention, the daily routine for Zhang Lu, Wu Fei, and Zhang Hongzhang involves a rigorous schedule of scientific experimentation. The Tiangong space station serves as a multidisciplinary laboratory, hosting experiments in fluid physics, materials science, basic physics, and space life sciences. The crew is currently managing several long-term projects within the pressurized modules, including the study of cell growth in microgravity and the testing of high-precision cold atom clocks.

The extended mission also allows the crew to participate in a significant cultural and political event: China Space Day on April 24. This date marks the anniversary of the 1970 launch of Dongfanghong-1, China’s first satellite. The 2026 celebrations are expected to be particularly robust, with major conferences planned in Chengdu and nationwide outreach programs aimed at inspiring the next generation of scientists and engineers. From their vantage point 400 kilometers above the Earth, the Shenzhou-21 crew will send messages of congratulations and participate in live educational "classrooms" broadcast to students across the mainland.

Broader Implications for the Chinese Space Program

The activities aboard Tiangong are only one facet of a rapidly accelerating Chinese space sector. In a press conference held on April 17, Liu Yunfeng, deputy director of the China National Space Administration (CNSA), provided updates on several ambitious projects that signal China’s intent to move beyond low-Earth orbit.

One of the most anticipated missions is Tianwen-2, a robotic probe designed to sample a near-Earth asteroid. Liu confirmed that the spacecraft is currently operating normally and is on approach to its target, the asteroid Kamo’olewa. Navigational maneuvers are expected to begin in June, with a rendezvous and sampling attempt likely occurring in early July. Kamo’olewa is of particular interest to scientists as it may be a fragment of the Earth’s moon, ejected during an ancient impact.

Furthermore, China is making significant strides in the development of reusable launch vehicles, a technology essential for reducing the cost of space access and competing with Western entities like SpaceX. The CNSA announced that the Long March 10B—a reusable variant of the rocket intended for future crewed lunar missions—is scheduled for a critical flight test between April 28 and 30. This test will likely include a high-altitude "hop" and an attempt to recover the first stage using a specialized sea-based vessel equipped with a cable recovery system.

The commercial sector in China is also showing unprecedented vitality. Several private and semi-private companies are preparing for major launches in the coming months:

• Galactic Energy is preparing the Pallas-1, a liquid-fueled reusable rocket.
• Orienspace is moving toward the debut of Gravity-2, a heavy-lift vehicle.
• Landspace continues to iterate on its Zhuque-3 methane-fueled rocket, following the success of its predecessors.

Conclusion: A New Era of Orbital Operations

The successful completion of the third Shenzhou-21 EVA is a testament to the resilience and technical prowess of the Chinese human spaceflight program. By addressing the threat of orbital debris through proactive hardware installation, China is demonstrating a responsible approach to the long-term sustainability of its space assets.

As the Shenzhou-21 crew enters the final weeks of their extended mission, the focus will shift to the handover process for the incoming Shenzhou-23 crew. This continuous cycle of habitation, maintenance, and scientific discovery underscores the transition of Tiangong from a construction project to a fully operational national laboratory. With upcoming tests of reusable rockets and deep-space probes on the horizon, the events of April 2026 serve as a clear indicator that China’s presence in space is not only permanent but rapidly expanding in scope and sophistication. The record-breaking performance of astronauts like Zhang Lu highlights the human element of this technological surge, proving that the taikonaut corps is prepared for the even greater challenges of lunar exploration scheduled for the end of the decade.