A Shape-Memory Deployable Subsystem with a Large Folding Ratio in China’s Tianwen-1 Mars Exploration Mission

Once China’s Tianwen-1 Mars probe arrived in a Mars orbit after a seven-month flight in the deep cold space environment,it would be urgently necessary to monitor its state and the surrounding environment.To address this issue,we developed a flexible deployable subsystem based on shape memory polymer composites(SMPC-FDS)with a large folding ratio,which incorporates a camera and two temperature telemetry points for monitoring the local state of the Mars orbiter and the deep space environment.Here,we report on the development,testing,and successful application of the SMPC-FDS.Before reaching its Mars remote-sensing orbit,the SMPC-FDS is designed to be in a folded state with high stiffness;after reaching orbit,it is in a deployed state with a large envelope.The transition from the folded state to the deployed state is achieved by electrically heating the shape memory polymer composites(SMPCs);during this process,the camera on the SMPC-FDS can capture the local state of the orbiter from multiple angles.Moreover,temperature telemetry points on the SMPC-FDS provide feedback on the environment temperature and the temperature change of the SMPCs during the energization process.By simulating a Mars on-orbit space environment,the engineering reliability of the SMPC-FDS was comprehensively verified in terms of the material properties,structural dynamic performance,and thermal vacuum deployment feasibility.Since the launch of Tianwen-1 on 23 July 2020,scientific data on the temperature environment around Tianwen-1 has been successfully acquired from the telemetry points on the SMPCFDS,and the local state of the orbiter has been photographed in orbit,showing the national flag of China fixed on the orbiter.

Development Progress of China’s First Mars Exploration Mission:Its Scientific Objectives and Payloads

China’s first Mars exploration mission is scheduled to be launched in 2020.It aims not only to conduct global and comprehensive exploration of Mars by use of an orbiter but also to carry out in situ observation of key sites on Mars with a rover.This mission focuses on the following studies:topography,geomorphology,geological structure,soil characteristics,water-ice distribution,material composition,atmosphere and ionosphere,surface climate,environmental characteristics,Mars internal structure,and Martian magnetic field.It is comprised of an orbiter,a lander,and a rover equipped with 13 scientific payloads.This article will give an introduction to the mission including mission plan,scientific objectives,scientific payloads,and its recent development progress.

Research Progress and Preliminary Scheme of Space Transportation System for Human Mars Exploration

Human Mars exploration has significant values in terms of exploring extraterrestrial life,interplanetary immigration,promoting science and technology development,and the progress of human society.This paper summarizes the research progress on human Mars exploration and the corresponding proposed space transportation systems in the world,and analyzes the development trends.A preliminary scheme including the human Mars exploration mission architecture and corresponding space transportation system is then proposed,and the related key technologies are identified.The results can be a reference for future further research.

Russian Nuclear Rocket Engine Design for Mars Exploration

This paper is to promote investigation into the nuclear rocket engine （NRE） propulsion option that is considered as a key technology for manned Mars exploration. Russian NRE developed since the 1950s in the former Soviet Union to a full-scale prototype by the 1990s is viewed as advantageous and the most suitable starting point concept for manned Mars mission application study. The main features of Russian heterogeneous core NRE design are described and the most valuable experimental performance results are summarized. These results have demonstrated the significant specific impulse performance advantage of the NRE over conventional liquid rocket engine （LRE） propulsion technologies. Based on past experience, the recent developments in the field of high-temperature nuclear fuels, and the latest conceptual studies, the developed NRE concept is suggested to be upgraded to the nuclear power and propulsion system （NPPS）, more suitable for future manned Mars missions. Although the NRE still needs development for space application, the problems are solvable with additional effort and funding.

Child Neurodevelopment on Mars

This review article aims to gather differences and similarities between planet Mars and planet Earth to determine the necessities for the proper growth and development of the neonatal brain. Factors such as Environmental, Nutritional, Social, Stress, and Education are juxtaposed to understand the difference between pediatric neurodevelopment on both planets. The variation between each factor was analyzed to determine how significant the impact is on neurodevelopment for children. The factors to be discussed were generated based on extensive research on what is most important for proper early neurodevelopment. The five factors are the main categories branched out into subcategories to delve into more detail regarding neurodevelopment. Factors may vary based on the location on each planet, but the best average was cultivated to create a fair evaluation of the differences. Although each factor influences a different part of the brain, each factor (Environmental, Nutritional, Social, Stress, and Education) is equally vital for development anatomy and physiology of the brain.

Moderate Resolution Imaging Camera (MoRIC) of China’s First Mars Mission Tianwen-1

China's first Mars exploration mission will carry out comprehensive global surveys of the planet from data collected by instruments carried in orbit and roving on the planet itself.Goals of the mission include detailed inspections and surveys of key areas on the surface of Mars.One of the main scientific payloads installed on the orbiter is the moderate resolution camera.Its mission is to image the surface of Mars sufficiently to produce a global remote sensing image map of the planet,and to explore and record changes to the topography of Mars,including major geological structures,and to advance research on topography and geomorphology in general.The moderate resolution camera uses a lightweight and compact integrated design;its primary components are an optical module,a focal plane module,a camera control module,a power and interface module,a camera support module,a thermal control module,and a reference module.Radiometric calibration,color calibration,and geometric calibration have been carried out to ensure that the camera can acquire sufficient accurate data to complete mission goals.This paper introduces the camera's detection mission,its system composition,and its working principle;it also describes the camera's ground calibration tests and their results,and provides a reference for processing the camera's scientific data and for future applications.

Overview of the Mars climate station for Tianwen-1 mission

The background and scientific objectives of the Mars Climate Station(MCS)for Tianwen-1 are introduced,accompanied by a comparative review of the status of related meteorological observation missions and of advanced sensing technologies.As one of the China Tianwen-1 Mission’s principal scientific payloads,the MCS contains four measurement sensors and one electronic processing unit that are specially designed to measure local temperature,pressure,wind,and sound on the Martian surface.The MCS’s measurement principles,technical schemes,ground calibration techniques,and adaptability evaluation to the Mars surface environment of MCS are introduced in details.The conclusion presents measurement performance specifications of the MCS,based on ground test results,that will provide guidance to future research based on data from the Tianwen-1 and later Mars missions.

Patent Analysis and Research on Mars Sampling Technology

This article reviews Mars sampling and return technology,by retrieving and analyzing the patents of domestic and foreign sampling equipment and mechanism technology,Mars surface removal technology and ultra-highspeed light and small sample return technology.It conducts patent analysis from the macro-technical view down to the micro-specific content view using statistical,quantitative and qualitative analysis methods.In the process of macro-analysis,it analyzes patent data from multiple perspectives such as time,region,technical composition,and applicants,and establishes the development trends for Mars sampling and return technology at home and abroad.In the process of micro-analysis,through the analysis and interpretation of key patents,we can learn the development priorities and development direction of foreign Mars sampling and return technology.This paper also proposes China’s Mars sampling and return technology development suggestions.

中国的深空探测

At present,the moon and Mars are the main focus of deep space exploration,scientific pursuits are the initial goal,and extensive cooperation leads to a greater prospect.China has made many scientific achievements and built considerable infrastructure through its lunar and Mars exploration activities.In the future,China will continue to carry out deep space exploration activities with scientific goals as the driving force,develop the International Lunar Research Station,explore the sun,inner planets and asteroids,discover exoplanets and build an asteroid defence system.In order to support future deep space exploration missions,China will construct an integrated communication,navigation and remote sensing constellation and develop heavy-lift launch vehicles.China offers a wide range of opportunities for cooperation,upholds the central role of Committee on the Peaceful Uses of Outer Space(UNCOPUOS),and welcomes all countries in the world to participate in deep space exploration activities.

Overview of China’s 2020 Mars mission design and navigation

Scheduled for an Earth-to-Mars launch opportunity in 2020,the China’s Mars probe will arrive on Mars in 2021 with the primary objective of injecting an orbiter and placing a lander and a rover on the surface of the Red Planet.For China’s 2020 Mars exploration mission to achieve success,many key technologies must be realized.In this paper,China’s 2020 Mars mission and the spacecraft architecture are first introduced.Then,the preliminary launch opportunity,Earth–Mars transfer,Mars capture,and mission orbits are described.Finally,the main navigation schemes are summarized.

Effect of mixing section configurations on combustion efficiency of Mg-CO_(2)Martian ramjet

Experiments were conducted to determine the effects of the mixing section configurations on the Mg-CO_(2)Martian ramjet combustion efficiency.It was carried out at a mainstream mass flow rate of 110 g/s and a temperature of 810 K.The chamber pressure was measured under different configurations and Oxidizer to Fuel(O/F)ratios.Results showed that the engine achieved self-sustaining combustion and worked stably during experiments.The pre-combustion chamber is needed to increase the combustion efficiency and promote the full combustion of the powder.After the configuration of the pre-combustion chamber,the best combustion efficiency reached 80%when radial powder injection and lateral carbon dioxide intake were used.In addition,the O/F ratio in the pre-combustion chamber decreased from 0.67 to 0.31,resulting in an 8%increase in the combustion efficiency.It was speculated that different mixing section configurations and the variations in an O/F ratio within the pre-combustion chamber impacted the combustion efficiency and in essence,all affected the flow velocity and residence time of the two-phase flow in the com-bustion chamber.

Obtain martian magnetic pileup boundary by spectrum of low energy electrons

The electron spectrometer of Mars Express (MEX) provides the flux of low energy electrons (<20 keV) near Mars. 96 pieces of continuously measured data are analyzed, and the crossings of the magnetic pileup boundary (MPB) can be determined by fitting the energy spectrum of the low energy electrons. The shape and position of the MPB can be gained from these crossings, and they are in good agreement with the results obtained by the Mars Global Surveyor (MGS) and Phobos-2. In addition, we classify these crossings based on the crustal magnetic field nearby. It turns out that the position of MPB near the strong (>50 nT) crustal magnetic field is higher than the position of the MPB near the weak (<10 nT) crustal magnetic field. This result reflects the effect of the crustal magnetic field on the interaction between the Martian atmosphere and solar wind.