Mars Camera Deep Dive: Tianwen-1 and the Zhurong Rover

The Hong Kong Polytechnic University (PolyU) integrated information database · Module 04: Research This profile focuses on the Mars Landing Surveillance Camera developed by PolyU — which flew aboard Tianwen-1 (2021), China's first Mars mission, to photograph the lander's surroundings on the Martian surface and monitor the state of the Zhurong rover. It is another milestone in PolyU's space research beyond the Moon. For the lunar sampling system, see lunar-sampling-system.md; for the RCDSE institutional profile, see deep-space-exploration-research-centre.md; for the space overview, see aerospace-and-space.md. Sources are primarily PolyU press releases, PolyU publications and reputable media, all cited.

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# 1. At a glance

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# 2. What the Mars Camera does

The Mars Camera's job is to serve as "eyes" in the distant, harsh environment of Mars. According to the PolyU press release^※ and the multidisciplinary research press release^※, the Mars Camera's core functions include:

• Photographing the lander's surroundings: providing visual information for surface activities on Mars;
• Monitoring the Zhurong rover's status: providing status surveillance as the rover is deployed and begins driving;
• Confirming the deployment of the solar panels and antennae: according to PolyU materials, the camera's surveillance targets extend specifically to the deployment and condition of Zhurong's solar panels and antennae — the two components on which the rover's power supply and Earth communication depend. If they fail to deploy, the mission fails;
• According to earlier materials, the Mars Camera was also associated with identifying potential landing sites (through terrain mapping and geomorphological analysis techniques).

According to PolyU RCDSE materials^※, the Mars Camera is mounted on the outside top surface of the lander platform — a position that looks down over the entire top of the lander and the ramp for the rover's descent, capturing both the Martian terrain beneath and the full sequence of Zhurong slowly driving off the platform.

Mars is extremely far from Earth, communication suffers significant delay, and the environment (temperature, radiation, dust storms) is unforgiving; the camera must work reliably under all these conditions. This places extreme demands on the instrument's reliability, environmental tolerance, and space qualification — from atmospheric entry to successful landing, a Mars probe must operate entirely autonomously, because the one-way communication delay between Earth and Mars can exceed ten minutes. A ground team cannot intervene in real time; any command round-trip would be far too slow for the landing sequence itself, which takes only minutes. This means the Mars Camera must not only "capture clear images" but also "withstand" the shock of landing, all while automatically recording critical image data without human intervention for later analysis.

According to the PolyU press release^※, the Mars Camera specifications are as follows:

What does 6,200G mean? 1G equals the acceleration of gravity at Earth's surface (about 9.8 m/s²). A ~6,200G impact at landing means the instrument must withstand a momentary acceleration of about 60,760 m/s² — a force equivalent to roughly 6,200 times its own weight. This is why space instruments must pass rigorous "space qualification tests" (including vibration testing and thermal vacuum testing) before they are allowed to fly. The PolyU team designed a specialised shock-absorbing structure for the Mars Camera so it can still image properly after the landing impact.

Source strength: The Mars Camera's functions (photographing surroundings, monitoring Zhurong, solar panel/antenna deployment), mounting location, and mass/field-of-view/temperature/shock specifications are all documented in PolyU press releases and RCDSE materials.

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# 3. How the camera was built: a triple design of light, tough, radiation-resistant

The Mars Camera weighs only about 390 g — slightly more than a smartphone — yet must contend with three very different physical challenges in a single mission: heat, impact, and radiation. That is why, despite its small size, PolyU lists it among its "signature instruments". According to PolyU ISE department materials^※, three engineering design choices were made:

• Integrated thermo-dissipation: The camera travels from Earth to Mars for about nine months, experiencing a ~150°C temperature swing along the way, and must then operate in the cold of the Martian surface. The integrated thermo-dissipation structure "smooths out" both the heat generated by the imaging components and external temperature fluctuations, preventing electronics from failing due to rapid temperature swings;
• Layered metallic radiation protection: Deep space lacks the shielding of Earth's magnetic field and atmosphere; cosmic rays and solar energetic particles can damage image sensors. The camera uses a layered metallic structure to shield its sensitive components from radiation;
• Flexible shock absorbing structure: A ~6,200G impact at landing, transmitted directly to the lens assembly and sensor, would be enough to destroy the camera. The flexible shock-absorbing structure "absorbs" the impact, allowing the camera to image normally after the jolt.

According to PolyU materials, Professor Yung Kai-leung summarised the design challenge this way: the camera must maintain high reliability under extreme space-flight conditions while combining a wide field of view with low-distortion optics. Wide-angle and low-distortion are inherently in tension — the wider the field of view, the more prone the edges are to distortion. Only by keeping the image undistorted across a 170° diagonal field can the true posture of the rover and lander be "clearly seen".

Why fuss over 390 g? In deep-space missions, every gram of mass must be "carried" from Earth by rocket; launch costs are priced by the gram. The probe's mass budget is fought over by every subsystem, leaving an extremely tight allowance for a surveillance camera. Squeezing the camera to ~390 g means the three structures — thermal, radiation and shock — must all fit within that weight. Lightness is itself one of the hardest constraints in aerospace engineering, and one that best demonstrates precision design skill.

This design later earned international recognition: according to PolyU ISE materials^※, the Mars Landing Surveillance Camera received a Gold Medal with Congratulations of the Jury at the 48th International Exhibition of Inventions in Geneva in 2023, plus a special award from the Technical University of Cluj-Napoca in Romania. More notably, technologies developed for this camera were later transferred to applications in surgical robots — a camera that flew to Mars, with its thermal and precision-structure experience, ultimately found its way back to medical devices on Earth (see innohk-and-knowledge-transfer.md for knowledge transfer).

Source strength: Integrated thermo-dissipation, layered metallic radiation protection, flexible shock absorbing structure, Geneva Gold Medal, and technology transfer to surgical robots are all documented in PolyU ISE materials; Yung's statement on wide field of view and low distortion is a direct official quote.

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# 4. Tianwen-1 (2021): The nation's first Mars mission

According to PolyU materials and public reports, Tianwen-1 is China's first autonomous Mars exploration mission, achieving "orbiting, landing and roving" in a single mission — a first in the history of Mars exploration worldwide. Its timeline (according to public mission materials^※ and PolyU press releases) is roughly as follows:

Notably, Tianwen-1 did not land immediately upon arrival. According to public mission materials^※, after entering orbit in February 2021, the probe spent about three months circling Mars, repeatedly surveying the pre-selected landing zone to confirm terrain safety, before releasing the lander in May. This cautious "orbit first, then land" strategy minimised the risk of a first-time Mars landing and gave Wu Bo's team ample room to verify their terrain analysis.

The most perilous stretch of Mars exploration is the "seven minutes of terror" from atmospheric entry to touchdown: the probe plunges into Mars's thin atmosphere at extreme speed, sequentially completing aerodynamic deceleration, parachute deployment, and retro-propulsion, slowing from tens of thousands of kilometres per hour to near zero. The entire descent takes just minutes, but the one-way Earth–Mars communication delay exceeds ten minutes — meaning that by the time ground control receives the "entering atmosphere" signal, the landing is long since over. Success or failure is decided before the signal ever arrives. The entire process is autonomous; there is no time for ground intervention. This is exactly why, at the moment of touchdown, the Mars Camera on the lander platform working correctly and recording the rover's deployment is itself the ultimate test of the instrument's shock-resistant design. PolyU press releases record explicitly: Tianwen-1 soft-landed successfully in the pre-selected landing zone in Utopia Planitia on 15 May 2021, and the PolyU-developed Mars Camera immediately began its surveillance duties.

Why Utopia Planitia? Utopia Planitia is a vast, flat impact basin in Mars's northern hemisphere — open terrain with relatively few large boulders and steep slopes, suitable for a safe landing. Nor is it anonymous ground: back in the 1970s, NASA's Viking 2 lander touched down in the same area. Zhurong's choice of Utopia Planitia reflects both its flat, safe terrain and its scientific value as a region where water/ice activity may have existed in the ancient past (see Section 7 for Wu Bo's site-selection analysis). Once the landing site was fixed, the Mars Camera from Yung Kai-leung's team completed its mission of "surveillance of the landing state" on this plain.

The PolyU-developed Mars Camera flew with Tianwen-1, photographing the environment on the Martian surface and monitoring Zhurong — making PolyU Hong Kong's participant in this national first Mars mission. According to PolyU publications, the leading scholar was the first Hong Kong scientist to participate in the development of instruments for national space missions (see aerospace-and-space.md).

Source strength: Tianwen-1 as the nation's first Mars mission, the launch/orbit/landing/roving timeline, Utopia Planitia and Viking 2 are from public mission materials; the Mars Camera's participation and the Utopia Planitia landing are from PolyU press releases.

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# 5. Zhurong: the object of the Mars Camera's surveillance

The rover the Mars Camera watches is Zhurong (祝融号) — named after the fire god of Chinese mythology. Understanding it helps explain the weight behind the phrase "monitoring status". According to public mission materials^※:

Zhurong is solar-powered, which is precisely why the Mars Camera had to confirm, immediately after landing, whether the solar panels had deployed successfully — if the panels fail to unfold, the rover becomes an inert lump of metal that cannot harvest sunlight. It was designed for about three Martian months, but in fact persevered on Utopia Planitia for over a full Earth year, driving approximately 1,921 metres south — far exceeding its design lifetime.

Zhurong's ending also makes the harshness of the Martian environment clear. According to public mission materials^※, in May 2022, to ride out the approaching Martian winter and dust storms, Zhurong entered hibernation mode, with the plan of waking autonomously when conditions improved; but as of 2025 it has never reawakened, most likely because dust gradually accumulated on its solar panels, reducing power generation below the level needed for self-wakeup. Dust — utterly unremarkable on Earth — became the final straw that broke a Martian rover. This, in turn, underscores why the Mars Camera's images of the solar panels and antennae at the moment of landing were an indispensable part of mission-safety surveillance.

What did Zhurong bring back from Utopia Planitia? The rover under the Mars Camera's watch did not spend its year of roving idly. According to the Zhurong radar study published in Nature^※, using its ground-penetrating radar along a ~1,171 m traverse, Zhurong detected, beneath less than 10 metres of weathered regolith, a layered structure roughly 70 metres thick; the researchers infer this is a geological record of multiple flood deposits in Utopia Planitia during the Late Hesperian to Amazonian periods. Separately, according to a study in Nature Astronomy^※, the radar found buried polygonal terrain at about 35 metres depth, identifying sixteen polygonal wedge-shaped features within ~1.2 km, possibly related to ancient water/ice freeze–thaw processes. Although no direct evidence of liquid water was found within the detection depth, the researchers do not rule out saline ice in the subsurface. For this profile, the significance of these results is this: the mission the PolyU Mars Camera served was not a symbolic "flag-planting" exercise, but a mission that genuinely produced frontier planetary science.

Source strength: Zhurong's mass/dimensions/power/roving distance, May 2022 hibernation, dust accumulation as the reason for non-reawakening, and the orbiter's continued operations are from public mission materials; the 70 m layered structure, 35 m polygonal terrain, and saline-ice inference are from the Nature and Nature Astronomy studies.

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# 6. Development speed: under three years of focused effort

According to PolyU materials, the team was commissioned to start development in 2017 and completed the Mars Camera's development plus the corresponding space qualification experiments in under three years.

That pace is no small feat in aerospace engineering: space instruments typically require long, repeated testing from design to passing space qualification (proving they operate reliably under launch vibration, vacuum, extreme temperatures, radiation, and other conditions). Completing the full process in under three years reflects PolyU's mature capabilities in precision engineering and space qualification — a speed inseparable from the experience Yung Kai-leung's team had accumulated in developing the Camera Pointing System (for Chang'e-3 and Chang'e-4) and the lunar surface sampling and sealing system (for Chang'e-5 and Chang'e-6, see lunar-sampling-system.md).

The lead, Yung Kai-leung: one thread from the Moon to Mars. The Mars Camera is not the chance work of a "newcomer". The lead, Professor Yung Kai-leung, is the Sir Sze-yuen Chung Professor in Precision Engineering in PolyU's Department of Industrial and Systems Engineering. He had already developed the rotatable Camera Pointing System for Chang'e-3 and Chang'e-4, then led the surface sampling and sealing system used on Chang'e-5 and Chang'e-6 (see lunar-sampling-system.md). From the lunar near side to the far side and then to the Martian surface, Yung's team has carried "Made in Hong Kong" instruments to key nodes of national deep-space exploration. It is precisely because this "lunar line" came first that the Mars Camera's shock resistance and space qualification could be got right under three years — the camera is the natural fruit of PolyU's deep-space engineering accumulated to a certain depth, not a gamble from scratch.

Source strength: The 2017 start and under-three-year development and space qualification are from PolyU materials; Yung's chair title and his record with the Camera Pointing System and sampling/sealing system are from PolyU press releases and this site's lunar sampling profile.

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# 7. Two parallel contributions: building the camera and choosing the landing site

PolyU contributed more than a camera to the Tianwen-1 mission. It participated through two parallel technical lines — one "building the camera", one "choosing the landing site".

According to the multidisciplinary research press release^※, the team of Professor Wu Bo from the Department of Land Surveying and Geo-Informatics provided terrain mapping and geomorphological analysis support for Tianwen-1's landing-site selection:

• Shortlisted three candidate landing zones at the global scale — Amazonis Planitia, Chryse Planitia, and the eventual choice, Utopia Planitia;
• Used AI techniques to analyse more than 670,000 impact craters and about 2 million rocks, assessing terrain safety across the candidate zones;
• Generated high-resolution three-dimensional digital terrain models to help determine the precise landing ellipse.

The two lines interlocked tightly within the same mission: Wu Bo's team first "read the terrain" to calculate the safest landing point, then Yung Kai-leung's camera "watched the status" at that point, recording the landing and the full rover-deployment sequence. The synergy of "building the camera" and "reading the terrain" is a concrete expression of the RCDSE's "institution + two directors" organisational model (see deep-space-exploration-research-centre.md; Wu Bo's planetary mapping work in wu-bo-lunar-mars-topographic-mapping.md).

Source strength: Wu Bo's three candidate zones, 670,000 craters/2 million rocks, and 3D terrain models are from the PolyU multidisciplinary research press release.

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# 8. Aftermath: into the National Security Education Exhibition

The Mars Camera's significance extends beyond research. According to PolyU PAIR news^※, the PolyU-developed Mars Camera has been displayed at the National Security Education Exhibition Gallery — presented as an instance of Hong Kong's technological strength serving the nation's aerospace programme, folded into the narrative of national security and technological self-reliance.

This display elevates the Mars Camera from a "research instrument" to a symbol of Hong Kong's participation in the nation's science-and-technology strategy, carrying public significance beyond the technical. The gallery is generally open to the public and student groups; the Mars Camera, exhibited alongside a placard reading "Developed by The Hong Kong Polytechnic University", lets visitors directly connect "Hong Kong research" with "national aerospace programme" — such curation is itself a public-communication strategy, translating laboratory technicalities into a national narrative ordinary citizens can grasp.

Looking at the timeline, the Mars Camera has travelled a complete arc in the public eye: first publicised at project award in 2020, landed on Mars with Tianwen-1 in 2021, won the Geneva invention-exhibition Gold Medal in 2023, and entered the National Security Education Exhibition Gallery in 2024. Technical awards recognise "built well"; the exhibition recognises "significance" — together, they secure this 390-gramme camera's place in Hong Kong's public narrative.

Source strength: The Mars Camera's display at the National Security Education Exhibition Gallery is from PolyU PAIR news; the 2023 Geneva Gold Medal is from PolyU ISE materials; the nature of the gallery and its communication significance are analytical inferences.

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# 9. Placing the Mars Camera in PolyU's aerospace research landscape

The Mars Camera and the lunar sampling system together form the "twin stars" of PolyU's aerospace research:

From the Moon to Mars, from "sampling" to "surveillance", PolyU's instrument contributions span multiple key nodes of national deep-space exploration. This series of achievements has cemented PolyU's role as "Hong Kong's partner in national deep-space exploration" (see the overview in aerospace-and-space.md).

The Mars Camera's success also gave PolyU a "dual contribution" in the Tianwen-1 mission — Yung Kai-leung's team built the camera that monitored the landing, while Wu Bo's team handled the terrain mapping for landing-site selection (see wu-bo-lunar-mars-topographic-mapping.md). The collaboration of "building the camera" and "reading the terrain" in a single mission is a concrete expression of the RCDSE's "institution + two directors" organisational model (see deep-space-exploration-research-centre.md).

It is worth noting that although the Mars Camera and the Camera Pointing System both carry the name "camera", their functional roles are entirely different: the Camera Pointing System is a rotatable "eye" for photographing the lunar surface panoramas and building 3D terrain models; the Mars Camera is a fixed "surveillance device" mounted on the outside top of the lander platform, dedicated to recording key images of the landing moment and rover deployment. What they share is the necessity of passing stringent space qualification, and design leadership by Yung Kai-leung's team — which is why this database treats them as PolyU's "representative instruments" rather than isolated cases.

# Frequently asked questions about the Mars Camera

Who built the Mars Camera, and which mission did it belong to? It was developed and built by Professor Yung Kai-leung's team at PolyU, as one of the payloads on the lander of Tianwen-1 (2021), the nation's first autonomous Mars exploration mission. According to the PolyU press release^※, its official name is the Mars Landing Surveillance Camera.

What exactly does it watch? According to PolyU and RCDSE materials, it is mounted on the outside top of the lander platform, responsible for photographing the Martian terrain around the lander and monitoring the Zhurong rover's driving, as well as the deployment and condition of the solar panels and antennae — all critical to whether the rover can generate power and communicate with Earth.

How small, and how tough, is this camera? It weighs about 390 g in total, yet must withstand a ~150°C temperature swing between Earth and Mars and a ~6,200G impact at landing. It achieves this through three designs — integrated thermo-dissipation, layered metallic radiation protection, and a flexible shock absorbing structure — and won the Gold Medal at the Geneva International Exhibition of Inventions^※ in 2023.

Was the camera PolyU's only contribution to Tianwen-1? No. Besides Yung Kai-leung's camera, Professor Wu Bo's team performed the terrain mapping and landing-site selection analysis for the mission (see Section 7) — a dual contribution of "building the camera" and "reading the terrain". This made PolyU one of the few Hong Kong institutions to bear both instrument development and upstream scientific support in the same national Mars mission.

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