05年8月，美国宇航局将正式公布一份以此为基础的太空探索计划，详细描绘出人类重上月球的具体方案。
1969年7月16日，阿波罗11号载人飞船载着3名航天员，开始了人类的首次探索月球壮举。经过约38万公里的飞行，阿波罗11号在7月21日飞抵月球轨道。宇航员阿姆斯特朗及其同伴奥德林乘坐登月舱，降落在月球静海。
阿姆斯特朗首先爬出舱门，他环顾四周后，一步一步地爬下扶梯。他的左脚小心翼翼地首先触及月面，发现左脚陷入月面很少后，才鼓起勇气将右脚也踩上月面。人类成功完成了将足迹踏上地外星球的壮举。
阿波罗11号登月成功后，在1969年11月至1972年12月期间，美国宇航局（NASA）还相继发射了一系列阿波罗飞船，其中除阿波罗13号因服务舱液氧箱爆炸停止登月任务外，其余5次任务都成功完成。阿波罗登月计划完成之后，美国决定在以后的几十年内不再进行登月旅行。
阿波罗探月计划结束30多年后，美国总统布什在2004年初提出了“太空探索远景计划”（Vision forSpaceExploration）———2018年，人类将再次登上月球，并建立月球基地；从2020年开始着手为人类登上火星做准备。05年8月，美国宇航局已正式公布一份以此为基础的太空探索计划，详细描绘出人类重上月球的具体方案。
运输工具 新一代载人飞船CEV
重返月球，首先需要解决交通工具的问题。虽然阿波罗载人飞船是上世纪60年代的产物，未来人类登月的航天器却和它惊人的相似。由于当时使用的土星5号火箭已经停产30多年，美国宇航局必须找到新的大型火箭来将人类再次送上月球。
对于采用何种推进系统，美国宇航局的工程师们进行了长时间的争论，第一种选择是航天飞机的推进器，另一个选择则是使用发射卫星的火箭推进器。最后被选中的是前者，因为其花费较低，同时拥有强大的推进力。
登月发射装置将由5个航天飞机的主引擎和大型推进火箭组成。火箭高达40层楼，其载重量能达到125吨，几乎可以和土星5号媲美。每次发射的费用为5.4亿美元，几乎和航天飞机执行一次升空任务的费用相当。
同时，为了找到将在2010年退役的航天飞机的替代品，美国宇航局的工程师们正在开发新一代的载人探测飞行器（CEV）。它的任务是把宇航员送入近地球轨道以外的深层空间。CEV的外部防护层可以替换，而其本身能重复使用10次以上。最初版本的CEV能够容纳3人，每年能数次往返于地球和国际空间站之间。此外它还能用做载货。而未来更成熟版本的CEV则能够运送6人前往火星。
2005年7月，美国宇航局已批准两份价值各为2800万美元的承包合同，承包商包括洛克希德·马丁公司和波音公司。两项合同旨在2006年7月前对CEV工程系统的评估提供支援。为了缩短航天飞机退役与CEV首航之间的间隔，美国宇航局将于2006年初提前选择一家公司负责开发CEV系统。
从外形上看，CEV和阿波罗号飞船非常相似，但是空间大了一倍。它由指令舱和服务舱构成。指令舱是宇航员在飞行中生活和工作的座舱，也是CEV的控制中心。在重返月球之旅中，12吨重的指令舱将依靠与其结合为一体的服务舱提供推动力，往返于地球和月球之间。
CEV的首次载人航行将定在2011年，宇航员们乘坐的CEV将搭乘一枚铅笔形状的火箭前往国际空间站，这一任务将耗资2.8亿美元。
除了CEV，宇航员还需要着陆器来登陆月球。着陆器的主要作用是帮助CEV往返于月球轨道和月球表面。它的构造也大致和阿波罗号一样，由下降级和上升级两大基本部分组成：下降级是一个装载有火箭引擎的4脚登陆架，在离开月球时，用做宇航员间隔间着陆器的上升级将与下降级分离，把宇航员带回月球轨道。着陆器能携带4名宇航员，而阿波罗号的着陆器只能容纳两名宇航员。登月计划按计划将于2010年全面加快进展，登月所需的所有飞船估计要到2018年完工。
飞行方式 载人与载货飞船会合于地球轨道
交通工具确定后，剩下的就是登月旅行的具体步骤。上个世纪60年代，航天工程师们在策划首次登月时遇到的最大的技术难题就是如何在月球上着陆。为了得到最理想的计划，工程师们拿出了诸多设想。
第一种方案是直接登陆：发射一枚火星8号大型火箭，航行并降落到月球表面，完成任务后飞回地球。但是，如果要完成全程飞行，目前火箭的大小尚无法携带足够的燃料。另一种方案叫做“地球轨道会合”，即发射数架小型火箭，把探月之旅需要的器材分批送上太空。这些小型火箭将在地球轨道上会合，组合成一架大型宇宙飞船，但由于在太空组装飞船的太多未知因素，这一设想在1962年被放弃。
最终，设计阿波罗号的工程师确定采纳第三种方案———“月球轨道会合”：探月宇航员和需要的所有设备将被一枚土星5号火箭送上太空。离开地球轨道后，火箭第三级将朝月球飞去。进入月球轨道后，阿波罗号的指令舱和服务舱与着陆器进行分离。两名宇航员将乘坐着陆器登陆月球表面，一名宇航员留守指令舱。着陆器返回月球轨道后，将与指令舱结合，载着宇航员返回地球。
40年后，美国宇航局的工程师也遇到了类似的选择，新的登月步骤大致上和阿波罗号一致，但由于重返月球需要携带更多的宇航员和科学设备，其中又加入了“地球轨道会合”中的某些方案。
新的登月之旅中，一枚推进力强大的火箭将把着陆器和载货舱送上太空，之后另一枚较小的火箭再把CEV送上太空，分别进入地球轨道后，CEV将与着陆器和载货舱结合成一体。
之后，剩下的过程就大体和阿波罗号登月一样。4名宇航员将乘坐着陆器登陆月球，一个星期后，着陆器将离开月球表面，再次和等待在月球轨道上的CEV会合，返回地球。进入大气层之前，原本结合在一起的指令舱将抛弃服务舱，穿过大气层后，它将利用降落伞在陆地上着陆。但在着陆前，指令舱会掠过太平洋上空，如果情况紧急，它也能在水上降落。
登月目标 环形山边建立月球基地
科学家认为，再次登上月球的价值不仅在于让人类进一步掌握月球的起源与地球的关系，更重要的则是以月球为跳板，探索离我们更远的星球，因此建造月球基地将是登月的最终目的。
美国宇航局建议，从2018年开始，美国每年至少会进行两次登月任务，先遣的宇航员将利用月球上一切可利用的资源，最后建造一个月球基地。基地就像目前在各国建在南极的科考站一样，将包括生活区、电站和通讯系统。有了固定基地以后，宇航员便可以进行长期试验，涉及的领域包括太空生物学、地理学、天文学和物理学等。还有一些研究会探索人类身体对低重力、高强度太阳辐射等外太空环境的反应。
目前，科学家已经找到了建造月球基地的首选理想地点———位于月球南极附近的沙克尔顿环形山。环形山的边缘有80%的时间处于阳光的照射之下。距离该处只有10公里的位置还有两个区域，总共有98%的时间处于阳光的照射之下。科学家的设想是把生产电力的太阳能设施放置在阳光充足的区域，并通过微波或电缆与之相连。这样，位于沙克尔顿环形山边缘的区域就可以得到几乎源源不断的太阳能供应。月球的北极比南极较为平坦，但是那里可能会有面积达1.3万平方公里的永久性阴影区。
科学家还猜测，沙克尔顿环形山一带有较高浓度的氢元素储备，而氢是太空探测的主要燃料之一。同时在环形山内部的一些永久性阴影区可能藏有常年不化的冰。冰不仅可以满足月球定居者的饮用水需要，还可以为太空飞船生产燃料。借助这些月球本身的资源，宇航员能够建造发电、通讯和导航系统，当然还包括人类探索月球先驱的住所。可能被选作建造基地的地点还包括月球北极、月球背面的三处地点以及阿波罗号在1969年着陆的静海。
月球基地必须拥有检测月球物质、基地成员健康状况和生活食品的试验舱，一个生活舱，一个不加压的储藏舱，一个加工月球物质的小型化工厂，一个带观测室和气闸门的连接舱以便宇航员出入月球表面，以及两辆月球探险车。宇航员将驾驶探险车在月球贫瘠的表面寻找燃料和水。长期驻扎在月球基地的成员应当包括指令长、机械师、机械技师、医生、地质学家、化学家和生物学家。基地成员每两个月轮换一次。每次大约更换3到4名工作人员。
利用化工厂生产的产品和建筑材料，宇航员能将其扩建成为人类飞往火星的基地，将实验室建设成为年产10万吨产品生产能力的月球基地，当然，要实现后面的步骤则可能是下个世纪的事了。
远景计划 与机器人一同踏上火星
05年8月12日，美国宇航局成功发射一艘新型火星勘测轨道飞行器。它在2006年3月进入火星轨道，之后调整到距离火星表面上空约190英里处围绕火星飞行。如果任务成功，它将成为人类探索这颗红色星球的又一大得力助手。利用其携带的精密照相机等仪器，勘测器能拍摄到火星表面最清晰的地貌细节，这能帮助科学家选择人类登陆火星的理想地点。
目前已经在火星轨道和地表工作的勘测器不在少数：在火星轨道上有美国的火星全球勘察者、火星奥德赛和欧洲的火星快车。更引人注目的则是在火星表面“漫步”的勇气号和机遇号火星车。虽然人类登陆火星计划的具体实施要等到2020年以后，但是大致的设想现在已经开始逐步成型。
和登月相比，登陆火星显然困难很多。月球距离地球只有数日的旅程，而前往火星的载人旅行单程都将花去半年时间。就规模来说，登月仅需要两枚火箭，但载人探索火星则需要4到5枚大型火箭将载人飞行器和其他科学仪器送上太空。同时，土星5号火箭曾使用过的同类型强大推进力引擎可能被再次使用。而在载有6名宇航员的火星探索飞船升空之前，一个火星基地必须已经修建完毕。通过远程控制系统，地球上的工程师将在火星上建造总部，电力、通讯系统，同时还要准备好一艘载人返航飞船。
降落到火星上后，宇航员将用500天的时间探索火星表面，进行研究。其中最受关注的就是找寻火星上可能存在的生命迹象。宇航员还将尝试在火星的地表环境中寻找氧气和水这两大维持生命的要素，还会尝试获得液态氧和甲烷等主要燃料。火星探测飞船在升空阶段引擎使用的是液态甲烷。由于火星大气中存在少量甲烷，有科学家提出飞往火星的宇航员能自己收集返航的燃料。
为了给人类登上火星做好充分的准备，美国宇航局还将在2007年发射凤凰号火星探测器。在2009年12月，美国宇航局还计划发射一个名为“火星科学实验室”的第三代重型火星车，它将于2010年10月抵达目的地。与勇气号和机遇号相比，“火星科学实验室”可以称得上是“大个子”，其重量达600千克，约有一辆吉普车大小。车上将负载两个实验室，其中每个实验室都包含着一个重达30千克的仪器舱。新火星车的穿行能力也将得到更多改善，它能够在坡度为60度的斜坡上正常行驶；其能源供应也将从太阳能电池“升级”为核能，因而可大大增加漫游车的行程和使用寿命，提高开展活动的能力，其设计寿命为至少2年。
参与火星探测的科学家表示，美国宇航局希望在人类登上火星之前将这个红色星球了解得越详细越好。由于涉及更具体的任务，未来火星上的机器人也会各具特色。美国宇航局正在开发一种遥控飞行翼，它将成为在火星地表进行低空飞行的“火星滑翔机”。目前正在测试的飞行翼模型翼展2.4米，由太阳能提供动力。未来的火星飞行翼的翼展将增大到20米，并且具有可伸缩性。科学家们的希望让这种飞行翼适应火星的环境，能够在火星恶劣的天气下顺利飞行和着陆，以此来够帮助工程师开发载人飞船安全着陆火星的系统。
由于依靠太阳能，火星飞行翼还有可能用作火星表面的发电站，为其他在火星表面着陆的探测设备提供能源。另一类火星机器人外表酷似蛇，它们的行动方式也像蛇一样，能在火星沙漠上曲折前行；此外，为了适应火星荒漠，美国宇航局的喷气推进实验室还开发了“风滚草”机器人，它们有排球大小，能和风滚草一样在沙漠灵活行动。
功能更强大的的火星机器人除了探测地表环境，收集数据，还能在程序的设定下建造适合人类居住的火星基地。在未来的火星地表，会有一种机器人外形类似建筑工地的铲土卡车，但是它们更小巧灵活，而且能完全智能化工作。由于能在土壤或沙地上进行挖掘，这种机器人可以替代人类探索条件恶劣的地点或者帮助修建火星基地。
而当首批人类宇航员登上火星时，也很可能会有机器人与宇航员做伴，让登陆火星更加安全。目前，美国宇航局艾姆斯实验室的科学家和工程师们正在一个室内实验室里计划如何模拟月球和火星的地质及地形，并研究机器人在这种情况下如何帮助人类在月球和火星上建造基地、试验设备及使用挖掘工具。科学家和工程师们正在试验具有人类特点的RobonautB型机器人，他们希望太空机器人能接受人类宇航员的指令、做出类似人类的反应，在需要的时候提供建议或要求帮助，同时也有自己行动的能力。
面临挑战 外太空环境威胁宇航员健康及预算困境
当然，再宏大的探索计划也不可避免地面临着技术和现实挑战。首要的问题就是如何在未知的外太空环境中保证宇航员的健康。
一直以来，科学家都非常担忧有害的太阳射线对宇航员身体的危害。研究显示，在地球低轨道上长时间停留的宇航员患致命癌症的风险比常人高3%.而对于地球轨道之外的外层空间辐射的危害，科学家们还知之甚少。1972年8月的一次大规模太阳风暴是迄今为止被记录的最强太阳辐射事件。工程师们则希望开发出能抵御四倍于那次辐射强度的CEV防护层。美国宇航局预测，拥有铝制外壳的CEV将能把宇航员患癌症的概率降低2.9%。
在已知技术和风险的范围内，美国宇航局预测探索月球的整体事故危险相对较小。研究数据显示，登月探险失败的概率低于6.3%，宇航员遇到生命危险的概率为1.3%.而在1962年对阿波罗号登月计划的评估显示，宇航员遇到危险的概率是22%。
除了技术上的风险，由于政治因素的变化，登月计划面临很多现实问题。关于科研项目所需天文数字开销的争论早已经开始。到2025年，该项目估计将花费2170亿美元。这仅比美国宇航局的太空探索部未来20年的财政总预算少70亿美元，也就是说其全部财力几乎都要用在登月计划上。
为了保证不超出预算，美国宇航局局长麦克尔·格里芬在上任后的三个月里花了大量精力，把宇航局的主要精力集中到重返月球上。格里芬在6月28日对国会说：“我希望你们会看到一份有逻辑、简单、直接的方案。”一位美国宇航局管理层的人士说：“我们不可能再像处理日常事务一样对待登月计划，格里芬很清楚这一点。为了达到目标，我们必须在财政和技术上更具创新意识。”
开销最大的一个阶段将是在航天飞机退役前的未来5年时间里，因为美国宇航局必须同时承担航天飞机任务和开发新的飞行器。但宇航局高官认为，只要不超出预算，资金来源将会得到保障。
2006年，美国宇航局的财政预算将达到170亿美元。如果未来20年宇航局每年的平均预算达到200亿美元，那么在4000亿美元的总预算中探月项目则占据了5成，达到54%.目前，美国宇航局的探月计划已得到了白宫和国会的支持。要使蓝图成真，还需要经历现实的考验，它在最终实现前还需要得到3届总统和5届国会的批准。不过，支持探月计划的人对此信心十足，正如一名参议员所说：“在一位有远见的总统领导下，我相信人们会燃起太空探索的渴望。国会也会鼎力支持，因为国会反映的是美国人的愿望。”
美国探索月球火星大事记
1961年-1967年
美国发射了9个“徘徊者”、7个“勘测者”探测器和5个月球轨道器，先后对月球进行了考察。
1965年
美国发射的水手4号宇宙探测器成功掠过火星，并传送回第一张火星表面的照片。
1969年7月20日
美国宇航员阿姆斯特朗乘坐阿波罗11号飞船登月成功，将人类的第一个足迹永远地留在了那里。激动不已的阿姆斯特朗说：“对我一个人来说，这是一小步，而对整个人类而言却是一个飞跃！”
1970年4月17日
执行第三次登月任务的阿波罗13号飞船发生氧气罐爆炸，但所幸的是3名宇航员成功返航，因而此次任务被称为“成功的失败”。
1975年
美国向火星发射了海盗1号和海盗2号宇宙飞船，并于1976年到达火星。
1998年1月6日
美国宇航局发射了“月球勘探者”探测器。它发现在月球的北极和南极有冰。最多可能达到100亿吨。
1996年
美国发射火星探路者探测器，1997年7月到达火星。此次观测的火星地面范围为有史以来最大。着陆舱发送回数千张照片，火星车也发送回550张图片。
2001年
2001年，美国发射奥德赛火星探测器。奥德赛于同年10月到达火星，其主要任务是在火星上寻找水或冰，并对环境进行研究。
2003年6月
美国发射火星车勇气号和机遇号，它们在2004年1月成功着陆。目前已经超期服役15个月，仍在火星表面继续进行探测工作。
2005年8月12日
美国成功发射火星勘测轨道飞行器，它将在2006年3月进入火星轨道，之后调整到距离火星表面上空约190英里处围绕火星飞行。其主要任务是寻找火星上可能存在的水，并为人类登上火星做准备。
译文:
Once Again Heading for the Moon: NASA's Plan of a Lunar Base
August, 2005: NASA officially publicises a space exploration program based on this and gives a detailed scheme of man's return to the moon.
On 16th July, 1969, Apollo 11, with 3 astronauts aboard, took off and began man's first exploration of the Moon. After a fly of about 380,000km, Apollo 11 got into the orbit of the Moon on 21st July. Astronauts Neil Armstrong and Buzz Aldrin took the lunar module and landed on the Mare Tranquillitatis.
Neil Armstrong got out of the module first. After a look around, he climbed off the staircase step by step. He touched the Moon surface first with his left foot and, finding that it sank but a little, gathered up his courage and put his right foot on the lunar surface, too. Man accomplished the deed of planting his footprints on an outer-terrestrial planet.
After the success of Apollo 11, NASA launched a series of Apollo spacecrafts from November, 1969 to December, 1972. All of them fulfilled their tasks except for Apollo 13, which was forced to suspend the mission because of an explosion of an oxygen tank in the service module. The US made a decision to carry out no more Moon-landing expedition in the future several decades after the Apollo program.
Thirty years after the Apollo program, American President George W. Bush proposed in early 2004 the Vision for Space Exploration. That is to say, man is going to be on the Moon again to build a lunar base in 2008 and make preparations for landing on the Mars from 2020 on. In August, 2005, NASA has officially publicised a space exploration program based on this Vision and given a detailed scheme of man's return to the Moon.
Conveyance - new generation manned spacecraft CEV
The means of conveyance is the first question to be dealt with. Though the Apollo spacecrafts were products back to the 1960's, the ones men are going to use bear striking similarities to it. As the Saturn V rocket has been out of production for over 30 years, NASA has to find new large rockets to send man back to the Moon.
There were longtime disputes over which kind of propulsion system should be adopted among the NASA engineers. The first choice is a space shuttle propulsion system and the other the rocket propulsion system for satellite launching. The former was chosen, because it cost less and had strong driving force.
The whole electropult will be composed of five shuttle main engines and a large propulsive rocket. The rocket is as high as 40 storeys and has a carrying capacity up to 125 tons, almost comparable to that of Saturn V. The expense for every launch is US$54million, almost as much as that for a liftup of space shuttle.
At the same time, in order to find substitutes for the space shuttle to be out of service in 2010, the NASA engineers are working on a new generation manned aerocraft CEV(Crew Exploration Vehicle), whose task is to send the astronauts into the deep space outside of the near-earth orbits. The exterior protective coating can be used for ten times and is replaceable. The first edition of CEV can hold three persons and make several flights between Earth and the international space station. It can also carry freight in addition. The maturer edition of CEV will be able to carry six persons to the Mars.
In July, 2005 NASA has authorised two contracts each worthy US$28 million, the contractors including Lockheed Martin and Boeing. The two contracts are signed for sponsoring the assessment of the CEV program before July, 2006. In order to shorten the interval between the retirement of the space shuttles and the virgin flight of the CEV, NASA will move up to early 2006 to choose a company to be in charge of the development of the CEV system.
The CEV looks very much like the Apollo spacecrafts in apperance but has an interior space twice as much as that of the Apollos. It consists of a command module and a service module, the former of which isthe control centre as well as where the astronaunts live and work. During the flight betweem the Moon and Earth, the 12-ton command module will be provided with the propulsive force by the service module which is combined to it.
The first manned flight of the CEV is due in 2011 when it will be carried by a pencil-shaped rocket to the international space station. The mission will cost US$280 million.
Beside a CEV, the astronauts will need a lander to get onto the Moon. The main function of a lander is to help the CEV in the journeys between the Moon orbit and its surface. Also constructed similar to the Apollo, it's composed of an ascent stage and a descent stage. The descent stage is a 4-foot stand equiped with a rocket engine. When leaving the Moon, the ascent stage will separate with the descent stage and carry the astronaut back to the Moon orbit. The lander of the CEV can carry four astronauts, while that of the Apollo could only carry two. The Moon landing program is scheduled to be in full swing in 2010 and all the spacecrafts needed for the landing is estimated to be completed in 2018.
Manner of Landing--Lunar Orbital Assemblage
The specifics of the landing remain to be agreed on after the problem of conveyance is solved. The biggest technical problem the aeronautical engineers encountered in the 1960's when making plans of the first Moon flight was how to land on the Moon surface. There were many alternatives suggested by the engineers for the most optimal plan.
The first one was a direct landing: to launch a Saturn VIII rocket, which was to travel and land on the surface of the Moon and fly back to Earth. However, the size of the rockets of that time deemed it impossible to carry fuel enough for the entire flight. Another scheme is called "orbital assemblage in Earth orbit", namely, to launch several small rockets and send the needed equipments into space in batches. These small rockets were to meet in the Earth orbit and assemble into a large spacecraft. This conception was given up in 1962 for there were too many unknowable factors in assembling a spacecraft in space.
The engineers who designed the Apollos finally adopted the third proposal --"orbital assemblage in Lunar orbit". The astronauts and all necessary equipments would be sent into space by a Saturn V. After leaving the Earth orbit, the third stage of the rocket would fly towards the Moon. Once in the lunar orbit, the command module and the sevice module of Apollo would separate with the lander. Two astronauts were going to get on the lunar surface in the lander, while the third stayed in the command module. When the lander returned to the Moon orbit, it would combine itself with the command module and carry the astronauts back to Earth.
Forty years later, the engineers of NASA are faced with the same choice. The new landing steps are more or less the same with that of Apollo, but because there will be more astronauts and scientific equipments this time, some points of the "Orbital Assemblage in Earth Orbit" scheme are added to the new one.
In the new Moon flight, a rocket with powerful propulsion will send the lander and the cargo module into space and is followed by another smaller rocket sending the CEV into space. After the three are all in the Earth orbit, they will combine into one.
The subsequent process is the same with the Apollo landing on the whole. Four astronauts will land on the Moon surface in a lander. After one week, the lander will leave the surface to meet the CEV which has been waiting in the lunar orbit and return to Earth. Before entering the aerosphere, the previously linked command module will discard the service module and after flying through the atmosphere, it will come down on the land with a parachute. Before the landing, however, the command module will fly over the Pacific Ocean and can land on the water in case of emergency.
Objective of Landing--a Lunar Base on the Rim of the Crater
Scientists believe that the value of a lunar return lies more in the exploration of farther planets with the Moon as a sringboard than gaining the knowladge of the origin of the Moon and its relation with Earth. A lunar base, therefore, will be the ultimate goal of the Moon landing.
NASA proposes that the US carry out at least two Moon landing missions every year since 2018. The first astronauts will make use of every resources available on the Moon and in the end establish a lunar base. The base will be like the scientific research stations at the south pole and comprise a living area, a power station, and a communication system. With a permanent base, the astronauts will be able to carry out longtime experiments covering fields of astrobiology, geography, astronomy, and physics. Other researches will be conducted to test the physical reaction of humans in the outer space environment of low gravity and strong solar radiation.
The scientists have located the ideal spot for the lunar base--the Shackleton crater at the lunar south pole, the rim of which is illuminated for about 80% of the lunar day. There are yet another two regions 10 kilometers away from the crater, where the sun shines for 98% of the time of a whole day. The scientists are planning to place the solar energy equipments in sunny areas and connect the base with them through microwave or cables, thus providing the area at the rim of the crater with solar energy virtually all the time. The North Pole on the Moon is smoother than the South Pole, but there might be a perpetual shaded area of up to 13,000 square kilometers.
The scientists also suppose there is a rich strorage of high hydrogen, which is one of the main fuels used in space exploration, in the areas aound the Shackleton crater. There may also be permafrost in some perpetual shaded areas inside the crater, which will not only satisfy the need of drinking water of the Moon dwellers but also be used to produce fuels for the spacecrafts. With these resources on Moon, the astronauts can set up systems of electricity, communication, and navigation as well as the dwellings for the forerunners of the human exploration of the Moon. Other places that may be selected for the base include the lunar North Pole, three sites on the farside of the Moon, and the Mare Tranquillitatis where the Apollo landed in 1969.
There must be an experiment module in the base for the test of lunar substances, the health of base dwellers, and food, a living module, an unpressurised storage module, a small chemical plant for processing lunar substances, a connective module with an observation room and an airlock chamber which allows the astronauts to go to and from the Moon surface, and two lunar roving vehicles, which the astronauts drive looking for fuels and water on the barren Moon surface. Long standing memebers on the Moon should include the commander, a mechanic, a mechanician, a doctor, a geologist, a chemist, and a biologist. The base members take shifts every two months, each time three or four members.
With products of the chemical plant and architectural materials, the astronauts are able to extend the base to one from which the mankind flies to the Mars and increase the productivity of the laboratory to 100,000 tons a year. But of course these are probably to be seen in the next century.
Perspective Plan--Landing on the Mars with Robots
On 12nd August, 2005, NASA successfully sent off a new model of Mars orbital reconnaissance aerocraft. It entered the orbit in March, 2006 and will readjust about 190 miles above the Mars surface circling around it. If the mission is accomplished, the rover will become another great help for human's exploration of this red planet. With the instruments such as precision cameras, the orbiter will take pictures of the minutest landscape details of the Martian surface, which will help the scientist locate the ideal spot for human landing.
There are not few rovers in the Martian orbit and on its surface. In the orbit are the Mars Global Surveyor and the Mars Odyssey of the United States and the European Mars Express. More remarkable are the rovers Spirit and Opportunity which are "rangering" on the Martian surface. Though the implementation of man's landing on the Mars will be after 2020, the rough conception has taken form.
The Martian landing is obviously much more difficult, compared to the Lunar landing. The Moon is but several days journey away from Earth, while a single manned flight to the Mars will take half a year. In terms of the scale, a Moon exploration needs only two rocket, while a manned Martian exploration needs four or five big rockets to send the manned aerocraft and other scientific instruments into space. Meanwhile, the same type of powerful propulsive engine the Saturn V rocket used may be put into use again. A Martian base must be completed before the exploration spacecraft with six astronauts aboard lifts up. The engineers on Earth will help build a control centre, the systems of electricity and communications on the Mars through long distance control system and at the same prepare a manned homeward spacecraft.
After the landing, the astronauts will spend 500 days surveying the Martian surface and doing research. The one object paid with the most attention is to look for the possible microbial life on the planet. The astronauts will try to find out oxygen and water, the two essential elements for life in the surface circumstance and try to obtain lox and liquid methane, the latter of which provides the main power supply in the launching stage of the rover. The scientists have suggested that the astronauts be able to collect fuels for the return flight, for there's a little methane in the Martian atmosphere.
In order to fully prepare the humans for landing on the Mars, NASA will launch the Phoenix Mars lander in 2007. NASA has also planned the liftoff of the third generation Martian rover named the Mars Science Laboratory in December, 2009, which is to reach its destination in October the next year. With a weight up to 600kg and the size of a jeep, the Mars Science Laboratory can be called "large" compared with the Martian exploration rovers Spirit and Opportunity. It will carry two laboratories, each including an instrument module as heavy as 30kg. The moving capacity of the new rover will also be greatly improved to be able to drive on a slope of 60 degrees; its power supply will also upgraded from solar energy batteries to nuclear energy and thus greatly increase the journey length and the service life and mobility. The designed service life is at least two years.
Scientist partisipating in the Martian exploration explain that NASA hopes to know as much as possible about the red planet before humans set foot on the Mars. In accordance with more specific tasks, Maritian robots will each have their particular features. NASA is developing a telecontrolled flying wing which is to be the "Martian glider" carrying out low flights near the Martian surface. The the model in test has a 2.4-metre wingspan and is powered by solar energy. The wingspan of the Martian flying wings will be extended to 20 metres and the wings will be retractable. The scientists expect the flying wings will adapt to the Martian environment and be able to fly and land in the tough Martian weather, thus helping the engineers develop the safe landing system of manned spacecrafts.
When on the Mars surface, the Mars flying wing may, for its ability to generate solar energy, be also used as a power station for other explorative devices that land on the surface. Another kind of Martian robots resemble snakes a lot , in apperance and in manner, moving zigzag on the Martian deserts. Another model named "Tumbleweed" specifically adapted to the Martian deserts is also developed by the Jet Propulsion Laboratory of NASA. The size of a volleyball, it can move around adroitly in the deserts.
The more powerful Martian robots will be programmed to build Martian bases suitable for human living apart from detect the Martian upper environment and collect statistics. On the future Martian surface, there will be a kind of robot shaped like a bucket shovel truck on a construction site but more agile and able to work completely intellectulised. Able to dig on soil or sand, this type of robot can replace humans to explore those tough places or help repair or build Martian bases.
When the first human astronauts get on the Mars, they are very likely to have the company of robots, which will make the landing on the Mars safer. At present, the scientists and engineers at the Ames Laboratory of NASA are planning on the simulation of the geology and landscape on the Moon and the Mars in an indoor laboratory and doing research in how robots can help man in such environments build bases, test equipments, and use digging tools. They are experimenting on the robonautB, a kind of robots with some human traits. They expect the space robots will be able to receive commands from human astronauts, display reactions alike humans, give advices or ask for them when necessary, and have the ability to act on their own.
Challenges--Health Hazard From the Outer Space Environment and Budget Impediment
Of course, an exploration program, however grand it is, is faced with technological and practical challenges. The first question is how to make sure of the health of the astronauts in the unknown outer space environment.
The scientists have always been worried about the damage done by the harmful solar radiation to the astronauts. Research reveals that an astronaut who stays long in the low Earth orbit suffers a risk of fatal cancer 3% higher than a common person, and scientists know yet little about the harm that might be caused by the outer space radiation. A large-scale solar storm in August, 1972 is the strongest solar radiation event ever recorded. The engineers are hoping to develop a CEV protective coating which can defend against a radiation four times stronger than that. NASA predicts a cancer risk 2.9% lower with a CEV coated with aluminium.
Within the known technological and hazardous range, NASA predicts a relatively low risk of the lunar exploration on the whole. Statistics show the probability of failure of the adventure to be lower than 6.3%, the probability of the astronauts in life danger to be 1.3%, while the evaluation of the 1962's Apollo lunar mission showed a probability of the astronauts in danger as 22%.
Beside technological risks, the Moon landing plan is faced with many realistic problems in accordance with political changes. The dispute over the astronomical cost of the scientific programs have long been under way. The expenses are estimated to have amounted to about US$217 billion by 2025, only US$7 billion less than the fiscal budget for the Space Exploration Department of NASA for the next 20 years. In other words, NASA will spend almost all its financial resources on the Moon landing program.
Michael Griffin, NASA chief administrator, made great efforts to reconcentrate the attention of NASA on the Lunar return in an attempt to confine the cost to the budget. Griffin spoke at the Congress 28th. June, "I hope you'll see a logical, simple, and direct scheme." A person in the NASA management said, "It's no possible possible for us to deal with the Lunar return programm as with some trivialities. and Griffin is very clear about this. To achieve our goal, we must be more innovative fiscally and technologically.
The most costly stage will be the final five years of the space shuttle's service life, because NASA has to undertake both the expenses of the shuttle in service and the development of new aerocrafts. But the high officials at NASA believe the financial source is guaranteed as long as the budget is not exceeded.
The fiscal budget of NASA in 2006 will be US$17 billion. If the yearly average budget of NASA in the future 20 years is US$20 billion, the Moon exploration program will take up 54% of the US$400 billion budget. The Moon exploration program has won support from the White House and the Congree, but before the blueprint finally comes true, there are still practical ordeals to overcome--the program must gain approval of three presidents and five congresses. Nevertheless, the apologists of the program are positively confident about this, as stated by a senator, "I believe people will be again ambitious of space exploration under the leadership of a foresighted president. The Congress will also give its full support, because the Congress stands for the wishes of the America."
The Exploarations of the United Stated of the Moon and the Mars
From 1961 to 1967
The United States launched nine Rangers, seven Explorers, and five Lunar Obiters for the reconnaissance of the Moon.
In the Year 1965
The space probe Mariner 4 of the United States flies by the Mars and returns the first pictures of the Martian surface.
20th July, 1969
The American astronaut Neil Armstrong landed on the Moon successfully in the spacecraft of Apollo 11 and left the first human footprint there. The excited Armstrong said, "That's one small step for man, but one giant leap for mankind."
17th April, 1970
The spacecraft Apollo 13 which was assigned the task of the third Moon landing was hindered by an explosion of an oxygen tank, but luckily, the three astronauts have returned successfully, which earned for this mission the name of "a successful failure".
In the Year 1975
The United States launched Viking 1 and Viking 2 orbiters, which reached the Mars in 1976.
6th January, 1998
NASA sent off the Lunar Prospector, which discovered ice at the North and South Poles on the Moon. The ice is estimated to be 10 billion tons at most.
In the Year 2001
In 2001, the United States launched the Odyssey, which arrived in the Mars, its major task being looking for water or ice on the planet and exploring the environment.
June, 2003
The United States launched two Mars exploration rovers, Spirit and Opportunity, which landed successfully in January, 2004 and which are still doing their reconnaissance work on the Martian surface after 15 months of service which is far extended from their scheduled mission life.
12th August, 2005
The United States successfully sent off the Mars reconnaissance orbiter, which is due to enter the Martian orbit in March, 2006 and readjust to 190 miles above the Martian surface to circle around the Mars. Its major task is to look for the possible water on Mars and make preparations for man's landing on the Mars.