Integrity of sulfur concrete subjected to simulated lunar temperature cycles

In view of potential application as a construction material on the lunar surface the mechanical integrity of sulfur concrete was evaluated after being subjected to simulated temperature cycles. Here, small cubes of sulfur concrete were repeatedly cycled between room (20 °C) and liquid nitrogen (−191 °C) temperatures after which they, and non-cycled cubes, were evaluated by compression testing. The compression strength of the non-cycled samples averaged ∼35 MPa (5076 psi) before failing whereas the cycled samples fractured at about 7 MPa (1015 psi). Microscopic examination of the fracture surfaces from the cycled samples showed clear de-bonding of the sulfur from the aggregate whereas it was seen adhering in those non-cycled. Based on a simple analysis it was concluded that the large strength discrepancy between cycled and non-cycled samples is due to differences between the coefficients of thermal expansion of the materials constituting the concrete.     

月面探测器月夜休眠自主唤醒方法

提出一种月面探测器休眠自主唤醒方法:月夜来临时通过地面控制对月面探测器所有设备进行休眠操作;月昼来临时靠太阳光触发唤醒功能,由休眠唤醒电路自主发送指令唤醒探测器,解决月面探测器安全可靠度过月夜的能源供给问题。该方法已通过在轨验证,可为其他深空探测任务提供参考。     

自由返回轨道的P平面参数快速设计方法

针对自由返回轨道求解过程中地心轨道类型变化造成的B平面参数方法计算失败问题,提出一种基于P平面参数的自由返回轨道快速设计方法。首先,基于轨道半通径参数的普适性,给出了不同轨道类型的P平面参数定义,建立了以P平面参数为求解目标量的自由返回轨道求解模型。其次,给出了基于P平面参数的自由返回轨道快速设计方法,在构建的瞬时地月惯性系下,以平面双二体自由返回轨道作为初值,实现了高精度力模型下的自由返回轨道快速求解。对8种构型自由返回轨道的设计结果表明,P平面参数具有类似于B平面参数的大收敛域,且有效解决了轨道类型变化对计算的影响,可直接应用于中国后续月球探测任务轨道设计。     

Conceptual study and key technology development for Mars Aeroflyby sample collection

Conceptual study of Mars Aeroflyby Sample Collection (MASC) is conducted as a part of the next Mars exploration mission currently entertained in Japan Aerospace Exploration Agency. In the mission scenario, an atmospheric entry vehicle is flown into the Martian atmosphere, collects the Martian dust particles as well as atmospheric gases during the guided hypersonic flight, exits the Martian atmosphere, and is inserted into a parking orbit from which a return system departs for the earth to deliver the dust and gas samples. In order to accomplish a controlled flight and a successful orbit insertion, aeroassist orbit transfer technologies are introduced into the guidance and control system. System analysis is conducted to assess the feasibility and to make a conceptual design, finding that the MASC system is feasible at the minimum system mass of 600 kg approximately. The aerogel, which is one of the candidates for the dust sample collector, is assessed by arcjet heating tests to examine its behavior when exposed to high-temperature gases, as well as by particle impingement tests to evaluate its dust capturing capability.     

Performance of a small and low-cost chamber to simulate lunar surface environment

The performance of a small and low-cost metal chamber built to simulate the pressure and temperature conditions of lunar surface was assessed and the results are presented. This chamber is intended for studying the physical properties of lunar surface and subsurface (using soil simulants) and also to validate the technology readiness of certain newly developed payloads planned for future lunar surface missions (Lander/Rover). It is possible to reach down to ∼10⁻⁷ Pa under specific conditions and maintain the temperature of the sample under investigation to lunar day and night temperatures. The designed system has been subjected to various tests to evaluate its performance and suitability for carrying out experiments in a simulated lunar environment.     

Role of the current young generation within the space exploration sector

The space sector gathers together people from a variety of fields who work in the industry on different levels and with different expertise. What is often forgotten is the impact and role of the current young generation. Their engagement is of great importance as undeniably today's young ‘space generation’ will be defining the direction of future space exploration.Today's vision of future human and robotic space exploration has been set out in the Global Exploration Roadmap (GER). This focuses on sustainable, affordable and productive long-term goals. The strategy begins with the International Space Station (ISS) and then expands human presence into the solar system, including a human mission to Mars.This paper presents a general overview of the role of today's youth within the space exploration sector and the challenges to overcome. To complete this perspective, we present results from a survey made among students and young professionals about their levels of awareness of the GER. The respondents presented their opinion about current aspects of the GER and prioritised the GER's objectives. It is hoped that the paper will bring a new perspective into the GER and a contribution to the current GER strategy.     

A permanent lunar base : Alternatives and choices

It appears virtually certain that humans will return to the lunar surface to stay and exploit the lunar resources. The only remaining question is who, when and how humankind will go there to establish a permanent lunar base. This article describes the decision-making process of determining the parameters of a lunar base. It offers modelling options as a frame of reference for planning the lunar base and its logistic support, and gives the reasons why a detailed analysis of the options and forward planning should have a high priority now.     

“龙江2号”月球轨道微卫星定轨分析

微纳卫星深空探测任务中,通常所分配的测控资源有限,因此有必要对有限测控资源条件下微纳卫星的定轨精度进行分析。以微纳卫星深空探测为背景,采用"龙江2号"微卫星的轨道测量数据对其定轨精度进行了分析。"龙江2号"微卫星只有USB轨道测量数据,且环月段测控资源相对紧张,每天有两站跟踪,共约3～4 h的轨道测量数据。首先介绍了"龙江2号"微卫星飞行任务及其飞行过程中影响测定轨的因素;其次给出了定轨的动力学模型,对微卫星地月转移段的定轨精度进行了分析;最后通过分析摄动力、动量轮卸载以及数据弧段长度的影响,给出了微卫星环月阶段所使用的定轨策略,并通过重叠弧段比较的模式,给出了微卫星环月段的定轨精度。研究结论可以为后续微纳卫星深空探测任务提供有益参考。     

低成本多小天体并行交会技术

小天体资源开发方兴未艾,为降低开发风险和成本,需要发射无人探测器交会观测多个待选目标小天体。传统多目标探测方案存在无法多次交会、成本高,周期长等不足。提出的低成本多小天体并行交会技术,能够对多小天体探测任务进行解耦,实现基于微纳飞行器的低成本多目标并行交会勘查,从而降低探测成本,缩短探测周期。该技术结合行星借力与不变流形机制构建了低能量星际转移方案。然后引入扰动流形思想,使微纳飞行器能够实现与目标小天体的快速交会。进一步,提出了一种多目标小天体探测全局搜索方法,该方法基于在日地halo轨道上停泊的微纳飞行器集群,逐次确定小天体探测目标,并利用上述方法完成了多微纳飞行器与多小天体的交会。数值仿真结果表明,该方案能够大幅度降低转移过程的燃料消耗,并缩短转移时间。