The Mars’ climate is cold and dry in the most recent epoch, and liquid water activities are considered extremely limited. Previous orbital data only show sporadic hydrous minerals in the northern lowlands of Mars excavated by large impacts. Using the short-wave infrared spectral data obtained by the Zhurong rover of China’s Tianwen-1 mission, which landed in southern Utopia Planitia on Mars, we identify hydrated sulfate/silica materials on the Amazonian terrain at the landing site. These hydrated minerals are associated with bright-toned rocks, interpreted to be duricrust developed locally. The lithified duricrusts suggest that formation with substantial liquid water originates by either groundwater rising or subsurface ice melting. In situ evidence for aqueous activities identified at Zhurong’s landing site indicates a more active Amazonian hydrosphere for Mars than previously thought.

https://www.science.org/doi/pdf/10.1126/sciadv.abn8555?download=true

Zhurong reveals recent aqueous activities in Utopia Planitia, Mars

The Tianwen-1 mission is China’s first Mars exploration mission. To complete the scientific objectives of “orbiting, landing, and patrolling” in one mission, thirteen instruments for acquiring multi-disciplinary data are configured. The data products with rich ancillary data and flexible structures will facilitate the data application. To integrate the requirements of experts from disparate disciplines and leverage new information technologies, a complete redesign of data products is promoted in the Tianwen-1 mission. We discuss the whole process of data product generation from the data pipeline design to data validation. We design the various data products according to the application requirements of each data type, including radar echo data, spectrum data, image data, energy spectrum data, magnetic field data, meteorological data, and acoustic data. Since various error sources will exist in the generation chain of the data products, data validation is essential before release to the public; the validation activities are discussed at the end. We deliver these scientific products to the community in a timely manner, with ancillary information and quality information. This paper can provide practical reference for Tianwen-1 data application.

/pdf/design-and-validation-of-the-scientific-data-products-for-4imhz2mb9d.pdf

Design and Validation of the Scientific Data Products for China’s Tianwen-1 Mission

Tianwen-1, China’s first Mars exploration mission, was successfully landed in the southern part of Utopia Planitia on 15 May 2021 (UTC+8). Timely and accurately determining the landing location is critical for the subsequent mission operations. For timely localization, the remote landmarks, selected from the panorama generated by the earliest received Navigation and Terrain Cameras (NaTeCam) images, were matched with the Digital Orthophoto Map (DOM) generated by high resolution imaging camera (HiRIC) images to obtain the initial result based on the triangulation method. Then, the initial localization result was refined by the descent images received later and the NaTeCam DOM. Finally, the lander location was determined to be (25.066°N, 109.925°E). Verified by the new orbital image with the lander and Zhurong rover visible, the localization accuracy was within a pixel of the HiRIC DOM.

Visual Localization of the Tianwen-1 Lander Using Orbital, Descent and Rover Images

The lack of adequate stereo coverage and where available, lengthy processing time, various artefacts, and unsatisfactory quality and complexity of automating the selection of the best set of processing parameters, have long been big barriers for large-area planetary 3D mapping. In this paper, we propose a deep learning-based solution, called MADNet (Multi-scale generative Adversarial u-net with Dense convolutional and up-projection blocks), that avoids or resolves all of the above issues. We demonstrate the wide applicability of this technique with the ExoMars Trace Gas Orbiter Colour and Stereo Surface Imaging System (CaSSIS) 4.6 m/pixel images on Mars. Only a single input image and a coarse global 3D reference are required, without knowing any camera models or imaging parameters, to produce high-quality and high-resolution full-strip Digital Terrain Models (DTMs) in a few seconds. In this paper, we discuss technical details of the MADNet system and provide detailed comparisons and assessments of the results. The resultant MADNet 8 m/pixel CaSSIS DTMs are qualitatively very similar to the 1 m/pixel HiRISE DTMs. The resultant MADNet CaSSIS DTMs display excellent agreement with nested Mars Reconnaissance Orbiter Context Camera (CTX), Mars Express’s High-Resolution Stereo Camera (HRSC), and Mars Orbiter Laser Altimeter (MOLA) DTMs at large-scale, and meanwhile, show fairly good correlation with the High-Resolution Imaging Science Experiment (HiRISE) DTMs for fine-scale details. In addition, we show how MADNet outperforms traditional photogrammetric methods, both on speed and quality, for other datasets like HRSC, CTX, and HiRISE, without any parameter tuning or re-training of the model. We demonstrate the results for Oxia Planum (the landing site of the European Space Agency’s Rosalind Franklin ExoMars rover 2023) and a couple of sites of high scientific interest.

/pdf/rapid-single-image-based-dtm-estimation-from-exomars-tgo-595tky2afr.pdf

Rapid Single Image-Based DTM Estimation from ExoMars TGO CaSSIS Images Using Generative Adversarial U-Nets

Landing Site Selection and Characterization of Tianwen‐1 (Zhurong Rover) on Mars

The High-Resolution Imaging Camera (HiRIC) is one major payload of China’s first Mars exploration mission, and its main objective is to obtain the detailed observation images of the key areas on the Martian surface. In this paper, the leading group of HiRIC shows a full blueprint of the HiRIC. The HiRIC can achieve a high resolution (0.5 m at an altitude of 265 km) with a wide swath width of 9 km. The HiRIC adopts an Off-Axis Three-Mirror Astigmatic (TMA) optical system with a focal length of 4640 mm, an F-number of 12 and a Field of View (FOV) of 2° × 0.693°. In order to reduce the instrument weight, carbon-based material is widely used in the opto-mechanical structure which is in ultra-lightweight design, thus, a light-weight camera with a total mass of 42 kg is obtained. The Time Delay and Integration (TDI) Charge Coupled Devices (CCDs) and Complementary Metal-Oxide-Semiconductor Transistor (CMOS) detectors are all set on the imaging plane to achieve the push-broom imaging and frame imaging, respectively. And the high Signal-to-Noise Ratio (SNR) >100:1 can achieve in multi observation types for various scientific imaging tasks. After 4-year design and fabricate, the HiRIC has been assembly. The testing results show that the instrument is in good condition, and the Modulation Transfer Function (MTF) can achieve 0.18 at Nyquist frequency. The HiRIC can achieve a well image on China first Mars exploration mission.

High Resolution Imaging Camera (HiRIC) on China’s First Mars Exploration Tianwen-1 Mission

The invention, which relates to the industrial automation field, provides a matrix type active temperature acquisition control system and acquisition control method for a space camera. Therefore, problems that that existing space camera temperature acquisition control system has the complicated structure and tedious testing process because of lots of cables and devices can be solved. The matrix type active temperature acquisition control system is composed of a temperature acquisition circuit, a temperature sensor, a heater, a heating circuit, a controller, a power module, a temperature acquisition matrix type cable and a heating matrix type cable. The temperature sensor collects temperature information of a corresponding measuring point of a space camera in real time and transmits the temperature information to the temperature acquisition circuit by the temperature acquisition matrix type cable; the temperature acquisition circuit converts the temperature information into a digital temperature signal and transmits the digital temperature signal to the controller; the controller outputs a heating control signal and sends the signal to the heating circuit; the heating control circuit transmits a heating voltage signal to the heater by the heating matrix type cable; and the heater heats the space camera. Therefore, the cable number for the active heat control system is reduced effectively.

Matrix type active temperature acquisition control system and acquisition control method for space camera

The invention discloses an image shift compensation calculation method based on an elliptical orbit, which relates to the aerospace field and aims at solving the problem that the existing image shift compensation model can not realize compensation on the image shift of the elliptical orbit. Based on a circular orbit image shift speed vector calculation model and parameters of the elliptical orbit, an image shift speed vector model for the elliptical orbit is built, and the elliptical motion orbit speed of a spacecraft, the perigee orbit speed and the apogee orbit speed are calculated; the included angle between the orbit speed and a centrifugal speed is calculated, the circular speed and the centrifugal speed can be acquired according to the calculated included angle, and the elliptical orbit height is calculated; the image shift speed converted by the circular speed of the spacecraft to an image plane passes through a scenic spot sub-satellite vertical horizontal coordinate system, a planetary coordinate system, a planetary inertial coordinate system, an orbit coordinate system, a camera coordinate system and an image plane coordinate system; and the image shift speed of the scenic spot on the image plane of the camera is acquired, and the elliptical orbit image shift is compensated according to the acquired image plane image shift speed.

He Yunfeng

Papers

High Resolution Imaging Camera (HiRIC) on China’s First Mars Exploration Tianwen-1 Mission

Matrix type active temperature acquisition control system and acquisition control method for space camera

Image shift compensation calculation method based on elliptical orbit