Role of sample return and sample science in low cost missions

Sample return is an essential component of solar system exploration. Samples provide a unique data set that is critical for understanding formation and evolution of our solar system. This uniqueness is based on the scale of observations, precision of measurements, the ability to modify experiments as logic and technology dictate, and the ability to use instruments free of the constraints on mass, power, reliability, and data rate of flight instruments. Advances in analytical capabilities in recent years enable fundamental measurements to be made on extremely small samples, greatly reducing mass constraints on robotic sample return spacecraft. Sample studies provide irreplaceable ground truth for remotely-sensed data on planetary surfaces and fit within a variety of architectures for human exploration of the solar system.     

System design of the Hayabusa 2—Asteroid sample return mission to 1999 JU3

The Japan Aerospace Exploration Agency is currently developing the second asteroid sample return mission, designated as Hayabusa 2. Following the successful return of Hayabusa from the asteroid “Itokawa”, Hayabusa 2 is designed as a round-trip mission to the asteroid “1999 JU3”. The 1999 JU3 is a C-type asteroid, which is believed to contain organic matter and hydrated minerals. Thus, it is expected that successful sample collection will provide additional knowledge on the origin and evolution of the planets and, in particular, the origin of water and organic matter. The current mission scenario will enable the spacecraft to reach 1999 JU3 in the middle of 2018 and perform an asteroid proximity operation for 1.5 years. Three touch downs for sampling and one 2-m-class crater generation by means of a high-speed impact operation are planned during the asteroid proximity operation. The samples are to be brought back to the Earth by a re-entry capsule. The present paper describes the system design of Hayabusa 2, some key technical challenges of the mission, and the development status.     

攻击型航空综合体作战效能分析的基本问题

以作战过程最为复杂的攻击型航空综合体为例，给出了与攻击型航空综合体作战效能分析相关的基本概念，简述了攻击机机群的基本作战过程，对其在完成作战任务的整个战斗机飞行过程中进行战效评估时所涉及到的基本问题－作战“剧本”的描述和所需要建立的数学模型等进行了较详细的介绍，阐述了各数学模型间的关系及各自应具有主要功能，为从系统工程观战来研究对地攻击机的作战效能，建立战效评估的顶层数学模型提供参考。     

A European probe to comet Halley

A European probe to comet Halley is proposed. The probe's model payload consists of 8 scientific instruments, viz. neutral, ion and dust impact mass spectrometers, magnetometer, medium energy ion and electron analyzer, camera, dust impact detectors and plasma wave experiment. Fly-by of the comet Halley nucleus will take place on November 28th, 1985, at about 500 km miss distance. The main spacecraft serves as relay link to transmit the observed data to Earth. As probe, a modified ISEE 2 design is proposed. Because of the cometary dust hazard expected in the coma a heavy dust shield (27 kg) is required, consisting of a thin front sheet and a 3 layer rear sheet. The probe is spin-stabilized (12 rpm), has no active attitude and orbit control capability and uses battery power only to provide about 1000 Wh for a measuring phase. A despun antenna transmits up to 20 kbit/s, in X-band. The total probe mass is estimated at 250 kg. The 3 model development programme should start in mid 1981 with Phase B.     

ASTEX: An in situ exploration mission to two near-Earth asteroids

ASTEX (ASTeroid EXplorer) is a concept study of an in situ exploration mission to two Near-Earth-Asteroids (NEAs), which consists of an orbiting element and two individual lander units. The target candidates have different mineralogical compositions, i.e. one asteroid is chosen to be of “primitive’’ nature, the other to be a fragment of a differentiated asteroid. The main scientific goals of the ASTEX mission are the exploration of the physical, geological, and mineralogical nature of the NEAs. The higher level goal is the provision of information and constraints on the formation and evolution of our planetary system. The study identified realistic mission scenarios, defined the strawman payload as well as the requirements and options for the spacecraft bus including the propulsion system, the landers, the launcher, and assessed and defined the requirements for the mission’s operational ground segment.     

租赁飞机的全流程工程管理

飞机退租工作是一项十分复杂的系统工作,退租工作能否顺利完成在一定程度可体现航空公司的工程管理能力。本文从航空公司工程管理人员的视角,阐述了如何使退租成本最小化,如何对租赁飞机进行全流程的工程管理。     

基于任务的作战飞机效能评估模型

针对作战飞机的任务效能评估问题,提出了基于作战飞机任务的任务效能新概念;采用概率分析方法将飞机作战过程分解并抽象为一组概率值,建立了相应的任务效能评估模型;该模型可以在兼顾传统仿真评估模型结果精度的同时,具有模型简明、计算消耗低、方便快捷等特点;更具有实际作战指挥意义,其快速可信的评估结果有利于作战指挥官进行合理的、科学的任务规划,从而有利于在执行特定任务时更好地运用现有的作战飞机和武器;算例结果表明该模型可以较为有效地对作战飞机携带不同机载武器时在不同作战环境中打击不同作战目标进行效能评估.     

Scheme design of the CHANG’E-5T1 extended mission

Flight schemes for the CHANG’E-5T1 extended mission are investigated in this paper. In the flight scheme and trajectory design, the remaining propellant of the CHANG’E-5T1 mission is utilized. The CHANG’E-5T1 mission is firstly introduced with feasible flight goals derived based on the terminal trajectory and satellite status. The flight schemes are designed to include a lunar return and the libration points in the Sun-Earth/Moon and Earth-Moon systems, with an emphasis on the Earth-Moon triangle libration point thus far unexplored. Secondly, three schemes are proposed for the CHANG’E-5T1 extended mission with different flight goals. The direct libration point orbit transfer and injection method is adopted to solve the issue in the transfer trajectory design. Furthermore, an innovative concept is proposed to transfer from the Earth-Moon collinear libration point to the triangle point using the Sun-Earth/Moon libration point. Finally, the merits and drawbacks of the three schemes are discussed in terms of flight time, control energy and frequency, flight distance, and goal value. As a result, the scheme including a lunar return and the Earth-Moon L2 libration point is selected for the CHANG’E-5T1 extended mission. A flight to the Earth-Moon libration point is achieved, replicating the achievement of the ARTEMIS mission.     

基于扩展状态深空探测器任务规划方法

面对深空探测过程中的不确定性,探测器需要利用任务规划技术实现自主控制。针对深空探测器任务规划中复杂系统功能及耦合操作约束,在状态知识框架的基础上,引入了扩展状态的概念。通过分析探测器任务规划中的约束关系,提出了基于扩展状态的任务规划算法。利用扩展状态结构特点削减了搜索空间,优化了搜索过程,提高了规划搜索的速度。数值仿真结果表明,该算法能够缩减近半的规划步数,加速问题求解进程,提高任务规划的效率。     

Future X-ray astronomy missions of Japan

Japanese future space programs for high energy astrophysics are presented. The Astro-E2 mission which is the recovery mission of the lost Astro-E has been approved and now scheduled to be put in orbit in early 2005. The design of the whole spacecraft remains the same as that of Astro-E, except for some improvements in the scientific instruments. In spite of the five years of delay, Astro-E2 is still powerful and timely X-ray mission, because of the high energy resolution spectroscopy (FWHM 6 eV in 0.3–10 keV) and high-sensitivity wide-band spectroscopy (0.3–600 keV). The NeXT (New X-ray Telescope) mission, which we propose to have around 2010, succeeds and extends the science which Astro-E2 will open. It will carry five or six sets of X-ray telescopes which utilize super-mirror technology to enable hard X-ray imaging up to 60–80 keV. In mid-2010s, we would participate in the European XEUS mission, which explores the early (z>5) “hot” universe.