Overview and status of a mirror fusion propulsion system design study

The main goal of this paper is to describe and emphasize the important discoveries made since 1986 in the engineering design of space fusion propulsion plants.

Among the important discoveries are four fundamental design principles (DPs) which should be used when adapting candidate Earth-based fusion-electric power plants to propulsion in space.

1. DP1. Maximize direct access to space for waste radiation.

2. DP2. Operate components as passive radiators whenever possible.

3. DP3. Optimize the plasma characteristics for best specific jet power

4. DP4. Optimize mission capability versus lifetime-mass-to-orbit (LMTO).

Another discovery is a design philosophy called IDEAs (Integrated Design Environment Algorithms) which is a tool for discovering new fundamental design principles.

These discoveries allowed us to adapt, and then to optimize, an earth-based fusion-electric magnetic-mirror-fusion reactor concept for propulsion in space. The resulting design is called the Mirror Fusion Propulsion System (MFPS); and its design status is reviewed.

This work can be used as a general road map for others attempting to convert earth-based designs to propulsion in space. It also has applicability to matter-antimatter propulsion systems engineering.     

Cost Engineering – The new paradigm for space launch vehicle design

The paper describes the basic definition and application of 'Cost Engineering' which means to design a vehicle system for minimum development cost and/or for minimum operations cost. This is important now and for the future since space transportation has become primarily a commercial business in contrast to the past where it has been mainly a subject of military power and national prestige. Several examples are presented for minimum-cost space launch vehicle configurations, such as increasing vehicle size and/or the use of less efficient rocket engines in order to reduce development and operations cost. Further a cost comparison is presented on single-stage (SSTO)-vehicles vs. two-stage launchers which shows that SSTOs have lower development and operations cost although they are larger, respectively have a higher lift-off mass than two-stage vehicles with the same performance. The design of a space tourism-dedicated launch vehicle is an extreme challenge for a cost-engineered vehicle design in order to achieve cost per seat not higher than $50,000. Finally an outlook is presented on the different options for manned Earth-to-Moon transportation modes and vehicles – another most important application of 'cost engineering', taking into account the large cost of such a future venture.     

Space manufacturing in the construction of solar power satellites

This paper deals with ongoing research work concerning energy budget and cost of the solar Satellite Power System (SPS).The fundamental model of such a total system including ground and space facilities, transportation vehicles, power satellites and rectennas is presented. The main purpose of this model is to examine the applicability of different construction scenarios to allow comparison under nearly identical constraints.Using this model in a first attempt the blankets—meaning the main part of the space segment by weight, energy investment needs and cost—are chosen representatively for the energy and cost comparison of two construction alternatives of the same SPS concept. These construction alternatives are defined just by ground and space based manufacturing of the solar blankets, while all other subsystems, operations and the transportation profiles are considered to be kept the same.It can be shown that the energy “payback” time does not only depend on the SPS concept selected but also very much on the construction and implementation scenario. The cost comparison of these alternative approaches presents not very significant differences but advantages for the space manufacturing option with potential higher differences for a less conservative approach which may apply benefits of space manufacturing meaning, for example, considerable mass savings in space.Some preliminary results are discussed and an outlook is given over the next steps to be investigated, comprising the extension of the fundamental model to include use of lunar raw materials.     

美国小行星俘获任务及其启示

小行星俘获(ACR)任务是美国Keck空间研究中心发起的一项深空探测任务。该任务计划选定一颗近地小行星,通过口袋式抓捕系统对其实施抓捕,并于2025年左右将其带回近月空间。文章介绍了ACR任务的内容和系统设计,具体包括:航天器总体构型、抓捕分系统、探测识别分系统和控制与推进分系统;对小行星抓捕的目标探测与识别、旋转匹配、抓捕、消旋、轨道转移等核心操作。基于ACR任务,提出了空间目标俘获技术的需求与应用、抓捕航天器系统设计的启示;基于我国目前的技术研究情况,总结分析了发展空间目标俘获任务所需的关键技术,如大功率柔性太阳翼、长时间大范围轨道机动、目标探测与识别、快速机动、目标抓捕与消旋。     

Design and implementation of the GPS subsystem for the Radio Aurora eXplorer

This paper presents the design and implementation of the Global Positioning System (GPS) subsystem for the Radio Aurora eXplorer (RAX) CubeSat. The GPS subsystem provides accurate temporal and spatial information necessary to satisfy the science objectives of the RAX mission. There are many challenges in the successful design and implementation of a GPS subsystem for a CubeSat-based mission, including power, size, mass, and financial constraints. This paper presents an approach for selecting and testing the individual and integrated GPS subsystem components, including the receiver, antenna, low noise amplifier, and supporting circuitry. The procedures to numerically evaluate the GPS link budget and test the subsystem components at various stages of system integration are described. Performance results for simulated tests in the terrestrial and orbital environments are provided, including start-up times, carrier-to-noise ratios, and orbital position accuracy. Preliminary on-orbit GPS results from the RAX-1 and RAX-2 spacecraft are presented to validate the design process and pre-flight simulations. Overall, this paper provides a systematic approach to aid future satellite designers in implementing and verifying GPS subsystems for resource-constrained small satellites.     

Chapman理论在再入走廊计算中的应用

再入走廊给出了飞行器满足任务要求、并安全返回地球的再入飞行范围,它是再入轨道优化、再入方案设计、再入飞行任务规划等的重要部分。文章通过再入动力学建模,引入Chapman假设,进行了航天器从外层空间返回的再入走廊的研究,分析了影响再入走廊边界的重要因素,并以航天飞机为例计算了再入走廊,验证了该分析方法的正确性。     

“伽利略”卫星在轨任务控制系统高级规范综述

重点描述了＂伽利略＂卫星在轨任务控制系统高级规范的相关内容,其中包括系统规范和子系统规范,如系统监测和控制子系统、遥测监测子系统、遥控指令子系统和数据归档子系统等;就如何借鉴＂伽利略＂卫星在轨任务控制系统高级规范,提出了一些开展我国星座卫星在轨任务控制系统设计的策略和方法,如设计方法、实现途径、自动化和安全策略等。     

导弹电动舵机系统的可靠性设计和预测

本文针对导弹电动舵机系统，应用我们提出的系统可靠性最优化设计方法，在给定系统总可靠度、各分系统费用配额和质量配额的条件下，设计舵机各部分的可靠度，首先建立基于相对对数可靠度概念的系统可靠性数学模型，确定了舵机各部分的相对可靠度与相对费用、相对质量及舵机系统级数之间的关系，应用极大值原理，通过数值求解，得到舵机各部分的可靠度。最后，对实际舵机各部分进行可靠性预测。预测结果与设计结果相一致，这说明本文提出的这种可靠性设计方法是成功的，具有普遍应用价值。     

Multiobjective optimization applied to structural sizing of low cost university-class microsatellite projects

In recent years, there has been continuing interest in the participation of university research groups in space technology studies by means of their own microsatellites. The involvement in such projects has some inherent challenges, such as limited budget and facilities. Also, due to the fact that the main objective of these projects is for educational purposes, usually there are uncertainties regarding their in orbit mission and scientific payloads at the early phases of the project. On the other hand, there are predetermined limitations for their mass and volume budgets owing to the fact that most of them are launched as an auxiliary payload in which the launch cost is reduced considerably. The satellite structure subsystem is the one which is most affected by the launcher constraints. This can affect different aspects, including dimensions, strength and frequency requirements. In this paper, the main focus is on developing a structural design sizing tool containing not only the primary structures properties as variables but also the system level variables such as payload mass budget and satellite total mass and dimensions. This approach enables the design team to obtain better insight into the design in an extended design envelope. The structural design sizing tool is based on analytical structural design formulas and appropriate assumptions including both static and dynamic models of the satellite. Finally, a Genetic Algorithm (GA) multiobjective optimization is applied to the design space. The result is a Pareto-optimal based on two objectives, minimum satellite total mass and maximum payload mass budget, which gives a useful insight to the design team at the early phases of the design.     

离子与霍尔电推进性能和质量的工程数据模型

为了提供航天工程任务设计时优选离子或霍尔电推进的通用对比分析方法,基于工程数据建立了包括推力器、电源处理单元、推力器选择单元、控制单元、推进剂气瓶、调压单元、流率单元、推力器支架、电缆、管路等产品的电推进的性能和质量经验模型。在此基础上通过推导建立了电推进系统干质量通用模型,模型变量参数包括推力器功率、推力器数量和推进...     

The future of human spaceflight.

After the Apollo Moon program, the international space station represents a further milestone of humankind in space, International follow-on programs like a manned return to the Moon and a first manned Mars Mission can be considered as the next logical step. More and more attention is also paid to the topic of future space tourism in Earth orbit, which is currently under investigation in the USA, Japan and Europe due to its multibillion dollar market potential and high acceptance in society. The wide variety of experience, gained within the space station program, should be used in order to achieve time and cost savings for future manned programs. Different strategies and roadmaps are investigated for space tourism and human missions to the Moon and Mars, based on a comprehensive systems analysis approach. By using DLR's software tool FAST (Fast Assessment of Space Technologies), different scenarios will be defined, optimised and finally evaluated with respect to mission architecture, required technologies, total costs and program duration. This includes trajectory analysis, spacecraft design on subsystem level, operations and life cycle cost analysis. For space tourism, an expected evolutionary roadmap will be described which is initiated by short suborbital tourism and ends with visionary designs like the Space Hotel Berlin and the Space Hotel Europe concept. Furthermore the potential space tourism market, its economic meaning as well as the expected range of the costs of a space ticket (e.g. $50,000 for a suborbital flight) will be analysed and quantified. For human missions to the Moon and Mars, an international 20 year program for the first decades of the next millennium is proposed, which requires about $2.5 Billion per year for a manned return to the Moon program and about $2.6 Billion per year for the first 3 manned Mars missions. This is about the annual budget, which is currently spend by the USA only for the operations of its Space Shuttle fleet which generally proofs the affordability of such ambitious programs after the build-up of the International Space Station, when corresponding budget might become again available.     

在轨操控机器人拓邻域搜索三维路径规划

针对空间在轨操控机器人在桁架式空间站执行操控任务时,需要在桁架间自由穿行且时刻与空间站保持接触的任务特性,提出基于拓邻域搜索蚁群算法的三维全局路径规划方法.该方法首先建立桁架式空间站的三维栅格模型;充分考虑机器人穿行时的包络约束和操控时的接触约束,在路径规划和轨迹搜索前对被操控对象的三维栅格模型进行预处理和修正,缩减路...     

Opportunity options for rendezvous,flyby and sample return mission to different spectral-type asteroids for the 2015–2025

The feasible rendezvous, flyby and sample return mission scenario to different spectral-type asteroids for the 2015–2025 are investigated. The emphasis is put on the potential target selection and the design of preliminary interplanetary transfer trajectory in this paper. First, according to different scientific motivations, some potential targets with different spectral-type and physical property are selected. Then, some optimal rendezvous and sample return opportunities for different spectral-type asteroids are presented by using pork-chop plots method and Sequential Quadratic-Programming (SQP) algorithm. In order to reduce the launch energy and total velocity increments for sample return mission, the Earth swingby strategy is used. In addition, the feasible trajectory profiles of flyby and rendezvous with two different spectral-type asteroids in one mission are discussed. A hybrid optimization method combing the Differential Evolution (DE) algorithm and SQP algorithm is introduced as a trajectory design method for the mission. Finally, some important parameters of transfer trajectory are analyzed, which would have a direct impact on the design of spacecraft subsystem, such as communication, power and thermal control subsystem.     

一种半解析方法火星再入探测器一体化设计模型

提出了一种火星再入探测器的半解析法一体化模型,为未来火星探测器的初步设计提供包括弹道、气动参数、防热系统在内的设计依据。在任务初步设计阶段,由于涉及多个学科,火星大气与地球大气模型差异很大,需要考虑的因素很多,因此需要一个半解析的,能够实时进行弹道、气动参数和防热层温度分布计算的设计工具。该工具应该包括气动外形、弹道、防热为一体的设计模型,且能满足计算负担要求。基于此,提出了一种普遍适应的火星探测器外形定义方程,并对其中的一种特殊情况进行了解析公式的推导。在合理假设的前提下,给出了计算防热层内部温度分布的半解析计算公式,并以MER\|B (Mars Exploration Rover)探测器为例进行了弹道和气动受热仿真。计算结果表明,该一体化计算模型的仿真计算落点与实际落点很接近,达到了火星探测器初步设计阶段一体化的计算要求。
     

嫦娥五号探测器供配电系统设计与验证

结合嫦娥五号探测器主要任务特点,简要介绍了多器供配电系统的功能需求、多器联合供电方案设计,并通过能量平衡仿真分析、多母线融合控制等关键技术,解决了嫦娥五号探测器在复杂空间环境下多任务、多模式的高可靠轻小型化供配电系统设计难题。在轨飞行试验结果表明:供配电系统功能正常、工作可靠、性能优良。提出的嫦娥五号探测器多器组合一体化供配电系统分析与设计方法,满足并确保了月面无人自动采样返回任务可靠实现,可为未来探月工程及其它深空探测领域供配电系统设计提供参考和借鉴。     

A gateway for human exploration of space? The weak stability boundary

NASA's plans for future human exploration of the Solar System describe only missions to Mars. Before such missions can be initiated, much study remains to be done in technology development, mission operations and human performance. While, for example, technology validation and operational experience could be gained in the context of lunar exploration missions, a NASA lunar program is seen as a competitor to a Mars mission rather than a step towards it. The recently characterized weak stability boundary in the Earth–Moon gravitational field may provide an operational approach to all types of planetary exploration, and infrastructure developed for a gateway to the Solar System may be a programmatic solution for exploration that avoids the fractious bickering between Mars and Moon advocates. This viewpoint proposes utilizing the concept of Greater Earth to educate policy makers, opinion makers and the public about these subtle attributes of our space neighborhood.     

The critical satellite technical issues of future pervasive broadband low-cost communication networks

Using a baseline design for a 30/20 GHz system, this paper addresses the critical technical issues of signal waveform design, projected spacecraft technology, satellite launch options and satellite cost. With DPCM (differential pulse-coded modulation) video signal encoding, 32 Mb/s user-to-user data rate per channel, 10% overhead, two orthogonal polarizations, and crosstalk loss limited to 1 dB, TFM (tamed frequency modulation—a type of QPSK) permits about 75 channels/GHz of frequency allocation, i.e. about twice the capacity possible with MSK or SFSK (types of QPSK). The BOM (beginning of mission) weight and power of a baseline 400-channel multi-beam satellite is about 1800 kg and 5000 W. Each 35 Mb/s channel can support 1–10 video channels depending on the signal processing at the ground terminals. These weight and power estimates assume hardened digital logic, composite material for a multibeam antenna structure, high-efficiency solar cells (45 W/kg), NiH₂ batteries and 10W/20 GHz power amplifiers. If more speculative late-1980s solar cell technology is assumed, then the BOM weight decreases about 10–15%. Using the Space Transportation System being developed by NASA, geosynchronous deployment options are shown as a function of communications capacity. Based on a cost model for large communication satellites, the total space segment cost of two active satellites and one spare would be about $485M. This system would have a peak capacity of 14 Gb/s or 400-35 Mb/s simultaneous one-way channels. Demonstration and/or initial system (ground plus space) costs would be significantly less. It is concluded that the above baseline satellite appears to be technically feasible in the late-1980s.     

卫星构形设计

卫星的构形,就是卫星的空间结构。构形设计是卫星一项重要的总体方案设计工作。文中论述了构形设计的任务、基本要求、外形与布局的关系以及模装的作用。     

Results of the parabolic flight tests of the rapunzel deployer

The tether assisted re-entry of small payloads is a highly interesting tool for space transportation especially for the return of small payloads from Space Station ISSA. The small tether mission Rapunzel was initiated in 1991 by the Institute of Astronautics, TU München and the Kayser-Threde Company, to design a low cost and feasible tether experiment for the verification of the tether assisted re-entry. Together with the Samara State Aerospace University, Russia, a mission concept on a Russian Resurs or Photon capsule was developed. Based on this mission a deployer has been designed, mainly based on technology of the textile industry, which insures high reliability at low cost. Recently a similar configuration is being discussed for the ESA-TSE mission.The main work during the recent time was the development and test of the breadboard model of the deployer system. After successfully completing initial ground tests with the deployer, further tests during the ESA Parabolic Flight campaign in November 1995 were conducted. After a short introduction of the overall mission scenario, the planned configuration in orbit, this paper will present the results of the microgravity test campaign onboard the KC-135 aircraft and compare them with the ground test. The deployer showed a good performance during all tests, including ejection of the end-mass, deployment, and braking. Problems that occurred during the tests will be discussed, and solutions for the detected flaws and the results of the redesign now in progress will be presented. These verifications have shown the feasibility of the concept and will lay the base for the planned development of the flight model of the deployer.