Small step or giant leap? Human locomotion on Mars

Human locomotion on Mars will be considerably different from on Earth. Optimum walking speeds will be approximately 30% lower and transitioning from a walk to a run will occur at a speed 25% slower. Peak vertical forces will be reduced by as much as 50%, and although ground contact time will remain constant with locomotion in 1 g, stride length and stride time will increase. During running on Mars airborne time will increase by approximately 80% in comparison to running on the Earth. On Mars, half as much energy will be required to travel the equivalent distance on Earth and it will be 65% more economical to run rather than to walk. Crews will, therefore, find themselves using a loping gait--a running-like action, with a slight upper body lean and an extended aerial phase, an unfamiliar gait in terrestrial locomotion.     

A review of muscle atrophy in microgravity and during prolonged bed rest

With the prospect of long duration space missions in Earth orbit or to Mars, there is a need for adequate information on the physiological adaptations that will occur. One consequence of prolonged exposure to microgravity is muscle atrophy (loss of muscle mass). After a long duration space flight, muscle atrophy along with skeletal calcium loss would affect the capacity of astronauts to re-adapt to gravity on return to Earth. Of importance are any countermeasures which can attenuate the adaptive responses to microgravity. Experimentation is difficult in space with small subject numbers and mission constraints. Prolonged bed rest using healthy volunteers is used as an Earth-based model to simulate the muscle atrophy which occurs in the microgravity environment.     

High energy-density propulsion—reducing the risk to humans in planetary exploration

The potential benefits to humankind of space exploration are tremendous. Space is not only the final frontier but is also the next marketplace. The orbital space above Earth offers tremendous opportunities for both strategic assets and commercial development. The critical obstacle retarding the use of the space around the Earth is the lack of low cost access to orbit. Further out, the next giant leap for mankind will be the human exploration of Mars. Almost certainly within the next 30 years, a human crew will brave the isolation, the radiation, and the lack of gravity to walk on and explore the Red planet. Both of these missions will change the outlook and perspective of every human being on the planet. However, these missions are expensive and extremely difficult. Chemical propulsion has demonstrated an inability to achieve orbit cheaply and is a very high-risk option to accomplish the Mars mission. An alternative solution is to develop a high performance propulsion system. Nuclear propulsion has the potential to be such a system. The question will be whether humanity is willing to take on the challenge.     

Volcano-ice interaction as a microbial habitat on Earth and Mars

Volcano-ice interaction has been a widespread geological process on Earth that continues to occur to the present day. The interaction between volcanic activity and ice can generate substantial quantities of liquid water, together with steep thermal and geochemical gradients typical of hydrothermal systems. Environments available for microbial colonization within glaciovolcanic systems are wide-ranging and include the basaltic lava edifice, subglacial caldera meltwater lakes, glacier caves, and subsurface hydrothermal systems. There is widespread evidence of putative volcano-ice interaction on Mars throughout its history and at a range of latitudes. Therefore, it is possible that life on Mars may have exploited these habitats, much in the same way as has been observed on Earth. The sedimentary and mineralogical deposits resulting from volcano-ice interaction have the potential to preserve evidence of any indigenous microbial populations. These include j?kulhlaup (subglacial outflow) sedimentary deposits, hydrothermal mineral deposits, basaltic lava flows, and subglacial lacustrine deposits. Here, we briefly review the evidence for volcano-ice interactions on Mars and discuss the geomicrobiology of volcano-ice habitats on Earth. In addition, we explore the potential for the detection of these environments on Mars and any biosignatures these deposits may contain.     

Effects of a simulated martian UV flux on the cyanobacterium, Chroococcidiopsis sp. 029

Dried monolayers of Chroococcidiopsis sp. 029, a desiccation-tolerant, endolithic cyanobacterium, were exposed to a simulated martian-surface UV and visible light flux, which may also approximate to the worst-case scenario for the Archean Earth. After 5 min, there was a 99% loss of cell viability, and there were no survivors after 30 min. However, this survival was approximately 10 times higher than that previously reported for Bacillus subtilis. We show that under 1 mm of rock, Chroococcidiopsis sp. could survive (and potentially grow) under the high martian UV flux if water and nutrient requirements for growth were met. In isolated cells, phycobilisomes and esterases remained intact hours after viability was lost. Esterase activity was reduced by 99% after a 1-h exposure, while 99% loss of autofluorescence required a 4-h exposure. However, cell morphology was not changed, and DNA was still detectable by 4',6-diamidino-2-phenylindole staining after an 8-h exposure (equivalent to approximately 1 day on Mars at the equator). Under 1 mm of simulant martian soil or gneiss, the effect of UV radiation could not be detected on esterase activity or autofluorescence after 4 h. These results show that under the intense martian UV flux the morphological signatures of life can persist even after viability, enzymatic activity, and pigmentation have been destroyed. Finally, the global dispersal of viable, isolated cells of even this desiccation-tolerant, ionizing-radiation-resistant microorganism on Mars is unlikely as they are killed quickly by unattenuated UV radiation when in a desiccated state. These findings have implications for the survival of diverse microbial contaminants dispersed during the course of human exploratory class missions on the surface of Mars.     

The Mars Sample Return Project.

The Mars Sample Return (MSR) Project is underway. A 2003 mission to be launched on a Delta III Class vehicle and a 2005 mission launched on an Ariane 5 will culminate in carefully selected Mars samples arriving on Earth in 2008. NASA is the lead agency and will provide the Mars landed elements, namely, landers, rovers, and Mars ascent vehicles (MAVs). The French Space Agency CNES is the largest international partner and will provide for the joint NASA/CNES 2005 Mission the Ariane 5 launch and the Earth Return Mars Orbiter that will capture the sample canisters from the Mars parking orbits the MAVs place them in. The sample canisters will be returned to Earth aboard the CNES Orbiter in the Earth Entry Vehicles provided by NASA. Other national space agencies are also expected to participate in substantial roles. Italy is planning to provide a drill that will operate from the Landers to provide subsurface samples. Other experiments in addition to the MSR payload will also be carried on the Landers. This paper will present the current status of the design of the MSR missions and flight articles.     

From Earth's orbit to the outer planets and beyond: Psychological issues in space

Current planning for the first interplanetary expedition to Mars envisions a crew of 6 or 7 people and a mission duration of around 2.5 years. However, this time frame is much less than that expected on expeditions to the outer solar system, where total mission durations of 10 years or more are likely. Although future technological breakthroughs in propulsion systems and space vehicle construction may speed up transit times, for now we must realistically consider the psychological impact of missions lasting for one or more decades.Available information largely deals with on-orbit missions. In research that involved Mir and ISS missions lasting up to 7 months, our group and others have studied the effects of psychological and interpersonal issues on crewmembers and on the crew-ground relationship. We also studied the positive effects of being in space. However, human expeditions to the outer planets and beyond will introduce a number of new psychological and interpersonal stressors that have not been experienced before. There will be unprecedented levels of isolation and monotony, real-time communication with the Earth will not be possible, the crew will have to work autonomously, there will be great dependence on computers and other technical resources located on board, and the Earth will become an insignificant dot in space or will even disappear from view entirely.Strategies for dealing with psychological issues involving missions to the outer solar system and beyond will be considered and discussed, including those related to new technologies being considered for interstellar missions, such as traveling at a significant fraction of the speed of light, putting crewmembers in suspended animation, or creating giant self-contained generation ships of colonists who will not return to Earth.     

Roadmap to a human Mars mission

We propose a new roadmap for the preparation of the first human mission to Mars. This proposal is based on the work of ISECG and several recent recommendations on human Mars mission architectures. A table is proposed to compare the possible benefits of different preparatory missions. Particular attention is paid to the possibility of qualifying important systems thanks to a heavy Mars sample return mission. It is shown that this mission is mandatory for the qualification of Mars aerocapture at scale-1, EDL systems at scale 1 and Mars ascent. Moreover, it is a good opportunity to test many other systems, such as the heavy launcher and the transportation systems for the trips beyond LEO. These tests were not mentioned in the last ISECG report. This strategy is facilitated in the case of the simplified Mars mission scenarios that have recently been presented because it is suggested that relatively small vehicles with small crew sizes are used in order to optimize the payload mass fraction of the landing vehicles and to avoid the LEO assembly. An important finding of the study is that a human mission to the surface of the Moon is not required for the qualification of the systems of a human mission to Mars. Since affordability is a key criterion, two important missions are proposed in the roadmap. The first is a heavy Mars sample return mission and the second is a manned mission to a high Earth orbit or eventually to the vicinity of the Moon. It is shown that both missions are complementary and sufficient to qualify all the critical systems of the Mars mission.     

一种三元结构的火星采样返回任务方案分析

介绍了目前国外提出的一种三元结构的火星采样返回任务方案,整个方案分3次发射,分别发射漫游车、着陆器和轨道器,每次发射间隔为4年,最终目的是将火星样品带回地球。该方案的优势在于,通过3次发射分别完成漫游车巡视勘察、着陆器现场探测、轨道器数据中继和在轨探测,最终综合完成火星采样返回,能够极大地缓解项目进度和资金压力,充分利用每次发射窗口分步骤完成探测任务。文章重点对方案涉及的关键技术进行了分析,包括样品获取与封装、行星保护、精准着陆、漫游车的危险规避能力和移动性、火星上升器、交会与样品捕获、地球再入器技术等;对方案的前景和优势进行了探讨,并给出几点启示,如精准着陆或成为今后行星探测着陆方式的新趋势,火星采样返回任务将是人类火星探测的里程碑,今后的深空探测任务趋向国际合作模式等。     

火星探测的主要科学问题

在太阳系的行星中,火星与地球之间存在最多的相似之处,因此,火星是一颗承载人类最多梦想的星球。火星有水和生命存在的问题,激发了人类火星探索的好奇心,成为人类持续探测火星的推动力。火星的起源和演化与太阳系形成过程的关系,火星与类地行星的共性和特性,是当代行星科学研究的重要内容。为了人类社会的可持续发展,火星可否改造成为适宜人类居住的绿色星球——这些是人类在火星探测中必须面对的重大科学问题。只有这些重大科学问题被一一解答,我们才能清晰地去思考地球和人类自身的未来！     

The effects of microgravity on the skeletal system--a review

Exposure of astronauts to microgravity leads to the loss of calcium from weightbearing bones. Prolonged exposure, e.g., during a journey to Mars, may present problems on return to Earth, with increased risk of fractures and premature osteoporosis in later life. The precise mechanisms of calcium loss have yet to be determined although a key feature is the absence of mechanical loading. Countermeasures aimed at reducing calcium loss to acceptable levels include the use of exercise, drugs, dietary modifications and inertia suits such as the Soviet "Penguin" suit. Missions of a number of years may, however, require the development of artificial gravity on a spacecraft. The country that first solves the physiological problems of man in space and, in particular, skeletal calcium loss, will almost certainly be the first to be able to put a man on Mars.     

火星探测器减速着陆技术分析

火星的大气环境和地球差异较大,存在着许多未知的因素,火星探测的减速着陆同样充满了风险和挑战。文章通过对美国火星探测减速着陆的重点技术进行分析,并归纳总结了火星探测器减速着陆技术的发展趋势。     

Stepping stones toward global space exploration

Several nations are currently engaging in or planning for robotic and human space exploration programs that target the Moon, Mars and near-Earth asteroids. These ambitious plans to build new space infrastructures, transport systems and space probes will require international cooperation if they are to be sustainable and affordable. Partnerships must involve not only established space powers, but also emerging space nations and developing countries; the participation of these new space actors will provide a bottom-up support structure that will aid program continuity, generate more active members in the space community, and increase public awareness of space activities in both developed and developing countries. The integration of many stakeholders into a global space exploration program represents a crucial element securing political and programmatic stability. How can the evolving space community learn to cooperate on a truly international level while engaging emerging space nations and developing countries in a meaningful way? We propose a stepping stone approach toward a global space exploration program, featuring three major elements: (1) an international Earth-based field research program preparing for planetary exploration, (2) enhanced exploitation of the International Space Station (ISS) enabling exploration and (3) a worldwide CubeSat program supporting exploration. An international Earth-based field research program can serve as a truly global exploration testbed that allows both established and new space actors to gain valuable experience by working together to prepare for future planetary exploration missions. Securing greater exploitation of the ISS is a logical step during its prolonged lifetime; ISS experiments, partnerships and legal frameworks are valuable foundations for exploration beyond low Earth orbit. Cooperation involving small, low-cost missions could be a major stride toward exciting and meaningful participation from emerging space nations and developing countries. For each of these three proposed stepping stones, recommendations for coordination mechanisms are presented.     

[Interior] Configuration options,habitability and architectural aspects of the transfer habitat module (THM) and the surface habitat on Mars (SHM)/ESA's AURORA human mission to Mars (HMM) study

This paper discusses the findings for [Interior] configuration options, habitability and architectural aspects of a first human spacecraft to Mars.In 2003 the space architecture office LIQUIFER was invited by the European Space Agency's (ESA) AURORA Program committee to consult the scientists and engineers from the European Space and Technology Center (ESTEC) and other European industrial communities with developing the first human mission to Mars, which will take place in 2030, regarding the architectural issues of crewed habitats.The task was to develop an interior configuration for a transfer vehicle (TV) to Mars, especially a transfer habitation module (THM) and a surface habitat module (SHM) on Mars. The total travel time Earth—Mars and back for a crew of six amounts to approximately 900 days. After a 200-day-flight three crewmembers will land on Mars in the Mars excursion vehicle (MEV) and will live and work in the SHM for 30 days. For 500 days before the 200-day journey back the spacecraft continues to circle the Martian orbit for further exploration. The entire mission program is based on our present knowledge of technology. The project was compiled during a constant feedback-design process and trans-disciplinary collaboration sessions in the ESA-ESTEC concurrent design facility.Long-term human space flight sets new spatial conditions and requirements to the design concept. The guidelines were developed from relevant numbers and facts of recognized standards, interviews with astronauts/cosmonauts and from analyses about habitability, sociology, psychology and configuration concepts of earlier space stations in combination with the topics of the individual's perception and relation of space.Result of this study is the development of a prototype concept for the THM and SHM with detailed information and complete plans of the interior configuration, including mass calculations. In addition the study contains a detailed explanation of the development of the Design process including all suggested design and configuration options.     

Magnetotactic bacteria on Earth and on Mars

Continued interest in the possibility of evidence for life in the ALH84001 Martian meteorite has focused on the magnetite crystals. This review is structured around three related questions: is the magnetite in ALH84001 of biological or non-biological origin, or a mixture of both? does magnetite on Earth provide insight to the plausibility of biogenic magnetite on Mars? could magnetotaxis have developed on Mars? There are credible arguments for both the biological and non-biological origin of the magnetite in ALH84001, and we suggest that more studies of ALH84001, extensive laboratory simulations of non-biological magnetite formation, as well as further studies of magnetotactic bacteria on Earth will be required to further address this question. Magnetite grains produced by bacteria could provide one of the few inorganic traces of past bacterial life on Mars that could be recovered from surface soils and sediments. If there was biogenic magnetite on Mars in sufficient abundance to leave fossil remains in the volcanic rocks of ALH84001, then it is likely that better-preserved magnetite will be found in sedimentary deposits on Mars. Deposits in ancient lakebeds could contain well-preserved chains of magnetite clearly indicating a biogenic origin.     

Piloted operations at a near-Earth object (NEO)

In late 2006, NASA's Constellation Program sponsored a study to examine the feasibility of sending a piloted Orion spacecraft to a near-Earth object. NEOs are asteroids or comets that have perihelion distances less than or equal to 1.3 astronomical units, and can have orbits that cross that of the Earth. Therefore, the most suitable targets for the Orion Crew Exploration Vehicle (CEV) are those NEOs in heliocentric orbits similar to Earth's (i.e. low inclination and low eccentricity). One of the significant advantages of this type of mission is that it strengthens and validates the foundational infrastructure of the United States Space Exploration Policy and is highly complementary to NASA's planned lunar sortie and outpost missions circa 2020. A human expedition to a NEO would not only underline the broad utility of the Orion CEV and Ares launch systems, but would also be the first human expedition to an interplanetary body beyond the Earth–Moon system. These deep space operations will present unique challenges not present in lunar missions for the onboard crew, spacecraft systems, and mission control team. Executing several piloted NEO missions will enable NASA to gain crucial deep space operational experience, which will be necessary prerequisites for the eventual human missions to Mars.Our NEO team will present and discuss the following:

• •new mission trajectories and concepts;
• •operational command and control considerations;
• •expected science, operational, resource utilization, and impact mitigation returns; and
• •continued exploration momentum and future Mars exploration benefits.

     

Issues in planetary protection: policy, protocol and implementation

Planetary protection is NASA's term for the practice of protecting solar system bodies from Earth life while protecting Earth from life that may be brought back from other solar system bodies. Spacefaring nations will soon begin retrieving samples from Mars and other solar system bodies. For these samples, planetary protection is in order, and measures are already in place to prevent the forward contamination of Mars and other bodies by Earth microbes and the backward contamination of Earth by possible extraterrestrial life. A major goal of planetary protection controls on forward contamination is to preserve the planetary record of natural processes by preventing human-caused microbial introductions.     

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.     

火星探测器着陆技术

火星着陆技术是火星探测的关键技术之一。由于火星环境与地球有很大不同,要实现火星探测的软着陆仍具有非常大的挑战性。介绍了各种火星着陆技术方案,对气动减速、控制和着陆缓冲等关键技术进行了分析。     

Strategic, technological and ethical aspects of establishing colonies on Moon and Mars

With the vast experience gained by Aerospace Community in the last five decades, the natural future course of action will be to expand Space Exploration. Our understanding of Moon is relatively better with a number of unmanned satellite missions carried out by the leading Space Agencies and manned missions to Moon by USA. Also a number of unmanned satellite missions and surface rover missions were carried out to Mars by those Space agencies generating many new details about Mars. While the future exploration efforts by global community will also be centered obviously on Moon and Mars, it is noteworthy that already NASA had declared its plans for establishing a Surface Base on Moon and developing the technical infrastructure required. Surface Bases on Moon and Mars give rise to a number of strategic, technical and ethical issues both in the process of development, and in the process of establishing the bases. The strategic issues related to Moon and Mars Surface Bases will be centered around development of enabling technologies, cost of the missions, and international cooperation. The obvious path for tackling both the technological development and cost issues will be through innovative and new means of international cooperation. International cooperation can take many forms like—all capable players joining a leader, or sharing of tasks at system level, or all players having their independent programmes with agreed common interfaces of the items being taken to and left on the surface of Moon/Mars. Each model has its own unique features. Among the technical issues, the first one is that of the Mission Objectives—why Surface Bases have to be developed and what will be the activity of crew on Surface Bases? Surface Bases have to meet mainly the issues on long term survivability of humans on the Mars/Moon with their specific atmosphere, gravity and surface characteristics. Moon offers excellent advantages for astronomy while posing difficulties with respect to solar power utilization and extreme temperature variations. Hence the technical challenges depend on a number of factors starting from mission requirements. Obviously the most important technical challenge to be addressed will be in the areas of crew safety, crew survivability, adequate provision to overcome contingencies, and in-situ resource utilization. Towards this, new innovations will be developed in areas such as specialized space suits, rovers, power and communication systems, and ascent and descent modules. The biggest ethical issue is whether humankind from Earth is targeting ‘habitation’ or ‘colonization’ of Moon/Mars. The next question will be whether the in-situ resource exploitation will be only for carrying out further missions to other planets from Moon/Mars or for utilization on Earth. The third ethical issue will be the long term impact of pollution on Moon/Mars due to technologies employed for power generation and other logistics on Surfaces. The paper elaborates the views of the authors on the strategic, technical and ethical aspects of establishing Surface Bases and colonies on Moon and Mars. The underlying assumptions and gray areas under each aspect will be explained with the resulting long-term implications.