Searching for alien artifacts on the moon

The Search for Extraterrestrial Intelligence (SETI) has a low probability of success, but it would have a high impact if successful. Therefore it makes sense to widen the search as much as possible within the confines of the modest budget and limited resources currently available. To date, SETI has been dominated by the paradigm of seeking deliberately beamed radio messages.However, indirect evidence for extraterrestrial intelligence could come from any incontrovertible signatures of non-human technology. Existing searchable databases from astronomy, biology, earth and planetary sciences all offer low-cost opportunities to seek a footprint of extraterrestrial technology. In this paper we take as a case study one particular new and rapidly-expanding database: the photographic mapping of the Moon's surface by the Lunar Reconnaissance Orbiter (LRO) to 0.5 m resolution. Although there is only a tiny probability that alien technology would have left traces on the moon in the form of an artifact or surface modification of lunar features, this location has the virtue of being close, and of preserving traces for an immense duration.Systematic scrutiny of the LRO photographic images is being routinely conducted anyway for planetary science purposes, and this program could readily be expanded and outsourced at little extra cost to accommodate SETI goals, after the fashion of the SETI@home and Galaxy Zoo projects.     

MAD with aliens? Interstellar deterrence and its implications

The possibility that extraterrestrial intelligences (ETIs) could be hostile to humanity has been raised as a reason to avoid even trying to contact ETIs. However, there is a distinct shortage of analytical discussion about the risks of an attack, perhaps because of an implicit premise that we cannot analyze the decision making of an alien civilization. This paper argues that we can draw some inferences from the history of the Cold War and nuclear deterrence in order to show that at least some attack scenarios are likely to be exaggerated. In particular, it would seem to be unlikely that the humanity would be attacked simply because it might, sometime in the future, present a threat to the ETI. Even if communication proves to be difficult, rational decision-makers should avoid unprovoked attacks, because their success would be very difficult to assure. In general, it seems believable that interstellar conflicts between civilizations would remain rare. The findings advise caution for proposed interstellar missions, however, as starfaring capability itself might be seen as a threat. On the other hand, attempting to contact ETIs seems to be a relatively low-risk strategy: paranoid ETIs must also consider the possibility that the messages are a deception designed to lure out hostile civilizations and preemptively destroy them.     

Finding a second sample of life on earth

If life emerges readily under Earth-like conditions, the possibility arises of multiple terrestrial genesis events. We seek to quantify the probability of this scenario using estimates of the Archean bombardment rate and the fact that life established itself fairly rapidly on Earth once conditions became favorable. We find a significant likelihood that at least one more sample of life, referred to here as alien life, may have emerged on Earth, and could have coexisted with known life. Indeed, it is difficult to rule out the possibility of extant alien life. We offer some suggestions for how an alternative sample of life might be detected.     

基于PolyMAX法的飞行器工作模态分析技术与应用

飞行器在大气中飞行时经历严酷的力热环境,结构动力学问题显著,而模态特性是分析这些问题的重要输入。传统地面模态试验很难准确模拟飞行环境,而工作模态分析技术能够得到飞行器实际飞行中的模态参数。文章首先简要介绍了工作模态分析技术的背景和发展现状,说明了PolyMAX法的基本原理,然后对飞行器飞行试验测量数据进行了处理和分析,采用PolyMAX法成功识别出该飞行器的模态参数,并进行了模态验证。     

The problem of active SETI: An overview

In the present paper (originally presented at the First IAA Symposium on Searching for Life Signatures hold at the UNESCO on 22–26 September 2008) I try to summarize the results of all my previous studies on active SETI and its possible dangers for us, also considering some new topics, in order to provide a possibly complete overview of the whole matter. First, I try to evaluate the possible risks of an indirect contact with aliens, from the social, cultural, and religious point of view; then, the possible risks related with receiving information about alien science and technology; finally, the risk that active SETI could increase the probability of a physical contact with hostile aliens. My conclusion is that active SETI is very unlikely to be dangerous for us, but, at present, such a possibility cannot be completely excluded. Surprisingly, it turns out that a very important point to be assessed in order to improve our evaluation of active SETI is the pace of our technological progress. Some suggestions about the policy that international community should adopt towards active SETI are also included.     

Corporate mergers - Lifeline for the space industry

The world's major space companies have undergone continual evolution, through a process of mergers and acquisitions, since their creation from their aerospace parents. Although much of this evolution occurred in the early years of the Space Age, the process seems to have become particularly dynamic in the 1990s, as companies have striven to become ever more competitive in an increasingly global business environment. This article reviews some of the most important mergers and traces the recent development of the world's leading space contractors.     

The progress of astronautics in China

China now has thirty years of experience in space. This article traces the development of China's space efforts and the successes China has achieved in space technology, particularly satellites and launchers. China's future plans for space activities are examined, including plans for cooperation with friendly countries, manned space flight, facilities to launch larger space vehicles, and participation in a permanent space station.     

ENGage: The use of space and pixel art for increasing primary school children's interest in science,technology, engineering and mathematics

The Faculty of Engineering at The University of Nottingham, UK, has developed interdisciplinary, hands-on workshops for primary schools that introduce space technology, its relevance to everyday life and the importance of science, technology, engineering and maths. The workshop activities for 7–11 year olds highlight the roles that space and satellite technology play in observing and monitoring the Earth's biosphere as well as being vital to communications in the modern digital world. The programme also provides links to ‘how science works’, the environment and citizenship and uses pixel art through the medium of digital photography to demonstrate the importance of maths in a novel and unconventional manner.The interactive programme of activities provides learners with an opportunity to meet ‘real’ scientists and engineers, with one of the key messages from the day being that anyone can become involved in science and engineering whatever their ability or subject of interest. The methodology introduces the role of scientists and engineers using space technology themes, but it could easily be adapted for use with any inspirational topic.Analysis of learners’ perceptions of science, technology, engineering and maths before and after participating in ENGage showed very positive and significant changes in their attitudes to these subjects and an increase in the number of children thinking they would be interested and capable in pursuing a career in science and engineering. This paper provides an overview of the activities, the methodology, the evaluation process and results.     

A systems engineering environment for integrated satellite development

Space mission implementation faces a very dynamic environment with fast-paced information technology advancement and shrinking space budgets. A more focused use of decreasing public investments in space requires a cost reduction over their entire life cycle, up to the end of the useful life of a spacecraft. The anticipation of cost, schedule, risk and performance requirements from all over the product life cycle to the early stages of product development is generally recognised as a necessary condition to reduce life cycle cost. In order to cope with the intrinsic functional complexity of space products, such requirements engineering activity must be performed in a structured way within a systems engineering approach. This paper aims to describe how Cradle, a commercial systems engineering environment software package, can be used for integrated satellite development, taking into consideration functional and life cycle process requirements. Cradle has requirements management, system modelling, performance modelling, configuration management and document generation capabilities integrated in the same environment. Also, the paper provides some examples of application and highlights how Cradle can enhance the satellite development related activities performed by the Brazilian Institute for Space Research (INPE).     

Radio frequency interference at Jodrell Bank Observatory within the protected 21 cm band

Radio frequency interference (RFI) will provide one of the most difficult challenges to systematic Searches for Extraterrestrial Intelligence (SETI) at microwave frequencies. The SETI-specific equipment is being optimized for the detection of signals generated by a technology rather than those generated by natural processes in the universe. If this equipment performs as expected, then it will inevitably detect many signals originating from terrestrial technology. If these terrestrial signals are too numerous and/or strong, the equipment will effectively be blinded to the (presumably) weaker extraterrestrial signals being sought. It is very difficult to assess how much of a problem RFI will actually represent to future observations, without employing the equipment and beginning the search. In 1983 a very high resolution spectrometer was placed at the Nuffield Radio Astronomy Laboratories at Jodrell Bank, England. This equipment permitted an investigation of the interference environment at Jodrell Bank, at that epoch, and at frequencies within the 21 cm band. This band was chosen because it has long been "protected" by international agreement; no transmitters should have been operating at those frequencies. The data collected at Jodrell Bank were expected to serve as a "best case" interference scenario and provide the minimum design requirements for SETI equipment that must function in the real and noisy environment. This paper describes the data collection and analysis along with some preliminary conclusions concerning the nature of the interference environment at Jodrell Bank.     

我国返回式卫星发展前景及关键技术问题

返回式卫星现阶段在经济与军事等方面有其巨大的应用价值,同时它也为航天高技术的核心——建立永久性载人空间站的两个先决条件——裁人技术与在轨技术提供试验条件,因此具有十分诱人的发展前景。我国返回式卫星具有自己的优势,充分发掘其潜力将产生很好的经济效益。尽早地安排一些关键技术的研究与试验,统筹兼顾主战场任务与航天高技术发展的需要,将使返回式卫星在发展我国航天高技术的总体规划中立新功。     

我国航天器带电技术研究进展

航天器与空间带电粒子环境相互作用引起的带电现象是其在轨发生故障和异常的重要因素。近年来,随着航天器性能的提升和技术发展,航天器带电技术研究的范围也大大扩展。文章简要回顾了我国航天器带电技术发展的历史,并从理论研究、地面模拟试验、数值模拟和带电防护等方面介绍国内航天器带电技术研究的进展。     

Towards a new remote sensing order?

This Viewpoint argues that the 1986 UN Principles on Remote Sensing have failed to anticipate the growth and broadening of the Earth observation field and are now less relevant. It traces the development of remote sensing: from a narrow government-controlled base, three distinct sectors of military, civil (i.e. public) and commercial Earth observation can now be distinguished and the latter is making images ever more widely and easily available. There has been no international effort to adjust the international legal regime to this changing environment and even the USA's remote sensing policy has basically been reactive. It is impossible now to conceive an overarching remote sensing policy and the challenge will be to shape each sectoral regime appropriately.     

SETI terminology: Do we interpret SETI terms correctly?

Many important SETI terms are either ambiguously defined or interpreted by different experts differently. Based on the author's experience with astronautical terminology (IAA multilingual space dictionary) a summary of the usual problems connected with an uniform definition of fundamental terms is attempted. In the second part several examples are quoted from the SETI literature—including the terms ETI, SETI and METI themselves, the definition of a habitable zone, of alien life, of an extraterrestrial artifact, of the Drake equation, of the Fermi-paradox, etc. In the third part of the paper a new task for the SETI social sciences community is raised, namely to collect “Lasting Universal Terms”; i.e. terms the meaning of which did not change since millennia, are independent on geographic position and also on the terrestrial environment and biology. Such terms might be preferably used in interstellar communication. All these questions are related to the manner how we might think about ETI and SETI in new ways. The paper tries to summarize the problems connected with exact SETI terminology and its potential implications for the future.     

利用并行八叉树划分技术开展复杂构型航天器放气污染分析研究

放气污染对航天器造成的有害影响需要定量评估。放气产物分子的输运过程可以采用Monte-Carlo方法模拟,并用射线表示放气分子输运轨迹。如此一来,即转换为射线追踪问题。由于航天器构型复杂,射线追踪的计算很耗时,所以有必要研究其加速算法。文章将复杂构型航天器表面用三角形非结构网格表示,利用八叉树划分技术开展分子运动轨迹与表面相交的加速模拟计算。同时,在基于共享内存多核计算平台,利用OpenMPAPI软件实现了计算的并行化。该方法在对空间站的实例计算中显著提高了运算速度,并对空间站的污染情况进行了初步评价分析。     

Limits on interstellar messages

Despite the fact that major efforts have been expended on passive searches for extraterrestrial signals, few deliberate “transmissions” to potential alien recipients have occurred. These have generally taken the form of simple graphics depicting such things as our appearance, location, and biological construction. In this paper, we consider (a) the fundamental technical and astronomical limitations to interstellar messaging—in other words, how many “bits” could any society reasonably send, and (b) what might be a likely transmission strategy. These considerations suggest approaches for SETI programs, as well as giving insight into the types of messages we might construct for eventual replies to received signals.     

航天器非地球轨道热环境模拟技术探讨

月球、火星探测器等非地球轨道航天器与地球轨道航天器对热控的要求有很大的不同,为验证热控设计的合理性,必须在地面做好充分的热环境模拟试验.国内绝大部分空间环模设备都是以模拟地球轨道航天器在轨环境为目的建设的,显然不能满足深空探测需要.文章针对航天器非地球轨道深空热环境模拟技术进行探讨.     

基于Vega的实时场景渲染技术研究

视景仿真因其能够帮助人们建立一个具有身临其境的沉浸感 ,能与复杂系统进行交互 ,并能促进构想与创造环境 ,而成为社会各个应用领域发展中不可或缺的高科技手段。Vega用于虚拟现实和实时视景仿真软件的开发 ,提供了快捷和很容易就可构造出复杂应用程序的手段 ,可以很好地实现视景仿真的实时场景渲染 ,使虚拟场景更加逼真 ,在视景仿真领域有着广泛的应用     

空间磁环境模拟技术

空间磁环境模拟技术是航天器环境工程的重要组成部分,随着航天器研制水平的提高而逐步发展壮大,并已经服务于我国航天器的研制工作。文章重点介绍了磁环境模拟设备研制技术、磁试验技术和航天器磁洁净技术的发展历程。     

Legal consequences of a SETI detection

If a detection of ETI takes place, this will in all probability be the result of either: (a) detecting and recognising a signal or other emission of ETI; or (b) the finding of an alien artifact (for instance on the Moon or other Celestial Body of our Solar System); or (c) the highly improbable event of an actual encounter. First and foremost, legal consequences regarding any of these contingencies will result from immediate consultations between nations on Earth. Understandings, memoranda and even agreements might be proposed and/or concluded. Such results within the field of terrestrial law will surely be a new branch of International Law, and particularly of International Space Law. At the same time, terrestrial nations will have to realize that any ETI will be self-determined intelligent individualities or organizations who might have their own understanding of “rules of behaviour” and thus, be legal subjects. Whether one calls such rules “law” or not: if two intelligent races—both of which have specific rules of behaviour—come into contact with each other, the basic understanding of such mutual rules will lead to a kind of “code of conduct”. This might be the starting point for a kind of Law—Metalaw—between different races in the Universe.