Planetary polar explorer – the case for a next-generation remote sensing mission to low Mars orbit

We propose the exploration of polar areas on Mars by a next-generation orbiter mission. In particular, we aim at studying the seasonal and regional variations in snow-deposits, which – in combination with measurements of temporal variations in rotation and gravity field – will improve models of the global planetary CO2 cycle. A monitoring of polar scarps for rock falls and avalanche events may provide insights into the dynamics of ice sheets. The mapping of the complex layering of polar deposits, believed to contain an important record of climate history, may help us understand the early climate collapse on the planet. Hence, we propose an innovative next-generation exploration mission in polar circular Low Mars Orbit, which will be of interest to scientists and challenging to engineers alike. Schemes will be developed to overcome atmosphere drag forces acting upon the spacecraft by an electric propulsion system. Based on the experience of missions of similar type in Earth orbit we believe that a two-year mission in circular orbit is possible at altitudes as low as 150 km. Such a mission opens new opportunities for novel remote sensing approaches, not requiring excessive telescope equipment or power. We anticipate precision altimetry, powerful radars, high-resolution imaging, and magnetic field mapping.

The New Wuqing 70 m Radio Telescope and Measurements of Main Electronic Properties in X-band

The new Wuqing 70 m radio telescope is firstly used for the downlink data reception in the first Mars exploration mission of China, and will be used for the other deep space communications and radio astronomical observations in the future. The main specifications and measurement results of some properties in X-band are introduced in this paper, such as pointing calibration, gain and efficiency, system noise temperature, system equivalent flux density, and variations with elevation. The 23 parameters pointing calibration model considering the atmospheric refraction correction in real time is presented in the telescope, and the pointing accuracy is reached 5.70″ in azimuth direction and 6.07″ in elevation direction respectively for different weather condi-tions. More than 62% efficiencies are achieved at full elevation range, and more than 70% in the mid-elevation. The system equivalent flux density of X-band in the mid-elevation is reached 26 Jy.

The Mars system revealed by the Martian Moons eXploration mission

Japan Aerospace Exploration Agency (JAXA) plans a Phobos sample return mission (MMX: Martian Moons eXploration). In this study, we review the related works on the past climate of Mars, its evolution, and the present climate and weather to describe the scientific goals and strategies of the MMX mission regarding the evolution of the Martian surface environment. The MMX spacecraft will retrieve and return a sample of Phobos regolith back to Earth in 2029. Mars ejecta are expected to be accumulated on the surface of Phobos without being much shocked. Samples from Phobos probably contain all types of Martian rock from sedimentary to igneous covering all geological eras if ejecta from Mars could be accumulated on the Phobos surface. Therefore, the history of the surface environment of Mars can be restored by analyzing the returned samples. Remote sensing of the Martian atmosphere and monitoring ions escaping to space while the spacecraft is orbiting Mars in the equatorial orbit are also planned. The camera with multi-wavelength filters and the infrared spectrometer onboard the spacecraft can monitor rapid transport processes of water vapor, dust, ice clouds, and other species, which could not be traced by the previous satellites on the sun-synchronous polar orbit. Such time-resolved pictures of the atmospheric phenomena should be an important clue to understand both the processes of water exchange between the surface/underground reservoirs and the atmosphere and the drivers of efficient material transport to the upper atmosphere. The mass spectrometer with unprecedented mass resolution can observe ions escaping to space and monitor the atmospheric escape which has made the past Mars to evolve towards the cold and dry surface environment we know today. Together with the above two instruments, it can potentially reveal what kinds of atmospheric events can transport tracers (e.g., H2O) upward and enhance the atmospheric escape. Graphical Abstract

The precision analysis of the Chinese VLBI Network in probe delay measurement

We propose a VLBI precision evaluation method for probe delay measurement, so as to investigate the error contributions from different components in the Chinese VLBI Network (CVN). This method takes the idea of traditional closure delay analysis for distant radio sources. It focuses on the VLBI closure delay only and therefore excludes the influence of probe orbit determination, which makes it very suitable to evaluate the capability of VLBI probe delay measurement. In this paper, we first introduce the principles of closure delay analysis. Then the statistical results of typical CE5 (Chinese Chang'e 5 lunar exploration mission) and HX1 (Chinese Mars exploration mission) observations are presented, including the comparison of the closure delay precisions between CE5 and HX1 for four closed baseline triangles in CVN. According to the result, we realize that, the precision discrepancy between CE5 and HX1 in the closure delay analysis is less than that of residual delay after orbit determination, which reflects the precision level of the VLBI delay measurement.

DeepLabV3+/Efficientnet Hybrid Network-Based Scene Area Judgment for the Mars Unmanned Vehicle System

Due to the complexity and danger of Mars’s environment, traditional Mars unmanned ground vehicles cannot efficiently perform Mars exploration missions. To solve this problem, the DeepLabV3+/Efficientnet hybrid network is proposed and applied to the scene area judgment for the Mars unmanned vehicle system. Firstly, DeepLabV3+ is used to extract the feature information of the Mars image due to its high accuracy. Then, the feature information is used as the input for Efficientnet, and the categories of scene areas are obtained, including safe area, report area, and dangerous area. Finally, according to three categories, the Mars unmanned vehicle system performs three operations: pass, report, and send. Experimental results show the effectiveness of the DeepLabV3+/Efficientnet hybrid network in the scene area judgment. Compared with the Efficientnet network, the accuracy of the DeepLabV3+/Efficientnet hybrid network is improved by approximately 18% and reaches 99.84%, which ensures the safety of the exploration mission for the Mars unmanned vehicle system.

GRaVN: A Convolutional Network Approach to Generalised Characterisation of Raman Spectra for Space Exploration

During planetary exploration mission operations, one of the key responsibilities of the instrument teams to determine data viability for subsequent analysis. During the 2019 CanMoon Lunar Sample Return Analogue Mission, the Lead Raman Specialist manually examined each spectra to provide quality assurance/validation. This non-trivial process requires years of experience to complete accurately. With the proven efficacy of Convolutional Neural Networks (CNNs) in classification tasks, and the increased use of automation and control loops on planetary space platforms for navigation and science targeting, an opportunity presents itself to approach this validation problem utilising CNNs. We present the Generalised Raman Validation Network (GRaVN), an neural network focused specifically on extracting the generalised structure of Raman spectra for quality assurance/validation. This work demonstrates the viability of utilising a CNN network in validation activities for Raman spectroscopy. Utilising only two hidden layers, a configuration was developed that provided good levels of accuracy on a manually curated dataset. This indicates that such a system could be useful as part of an autonomous control loop during planetary exploration activities.

Strategies for Deploying a Sensor Network to Explore Planetary Lava Tubes

Recently discovered pits on the surface of the Moon and Mars are theorized to be remnants of lava tubes, and their interior may be in pristine condition. Current landers and rovers are unable to access these areas of high interest. However, multiple small, low-cost robots that can utilize unconventional mobility through ballistic hopping can work as a team to explore these environments. In this work, we propose strategies for exploring these newly discovered Lunar and Martian pits with the help of a mother-daughter architecture for exploration. In this architecture, a highly capable rover or lander would tactically deploy several spherical robots (SphereX) that would hop into the rugged pit environments without risking the rover or lander. The SphereX robots would operate autonomously and perform science tasks, such as getting inside the pit entrance, obtaining high-resolution images, and generating 3D maps of the environment. The SphereX robot utilizes the rover or lander’s resources, including the power to recharge and a long-distance communication link to Earth. Multiple SphereX robots would be placed along the theorized caves/lava tube to maintain a direct line-of-sight connection link from the rover/lander to the team of robots inside. This direct line-of-sight connection link can be used for multi-hop communication and wireless power transfer to sustain the exploration mission for longer durations and even lay a foundation for future high-risk missions.

Scientific Goals of Rendezvous Mission to Apophis

The asteroid Apophis is one of the most potentially hazardous objects to Earth in human history, and many countries are paying attention to its 2029 approach to Earth. The asteroid’s 2029 encounter will not only greatly help promote understanding of the asteroid itself, but will also be a great opportunity to acquire knowledge of this Earth-threatening asteroid. The KASI (Korea Astronomy and Space Science Institute) is now conducting a pre-phase A study for the rendezvous mission to Apophis. In this article, I would like to explain the importance of research on the asteroid Apophis and address the scientific goals of this exploration mission.