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[专题专项] VASIMR 进展(更新:JSC与Ad Astra 展开合作)

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hkhtg090201 发表于 2009-10-13 17:17 | 显示全部楼层
美测试世界动力最强劲离子发动机
2009年10月13日 00:04  新浪科技

  新浪科技讯 北京时间10月13日消息,据英国《新科学家》杂志报道,美国一家公司日前对一台满负荷运转的新型离子发动机进行了测试,使得我们距离将宇航员快速送入太空的目标又近了一步。

  离子发动机或许会在五年内被用于维持国际空间站运行轨道,为将来一个月左右抵达火星的新型火箭的问世奠定基础。自2005年创建以来,位于美国得克萨斯州韦伯斯特市的艾德·阿斯特拉火箭公司(Ad Astra Rocket Company)一直在完善一种名为“可变比冲磁致离子浆火箭”(简称VASIMR)的新型发动机。

  VASIMR发动机使用无线电波加热氩气,将其变成炽热的等离子体——一种使电子不再受限于原子核的物态。接下来,磁场将超高温等离子体喷射到发动机后面,令其在反方向产生推力。VASIMR发动机以比常规发动机更快的速率喷射推进剂,使得每公斤燃料产生的加速度更多。

  艾德·阿斯特拉火箭公司的短期目标是,使用200千瓦VASIMR发动机为国际空间站的运行轨道提供周期性推力。由于大气阻力,国际空间站运行轨道的高度会逐渐下降。10月7日,该公司首次对满负荷运转的VASIMR发动机进行了测试——在休斯敦的一个真空室内运行了201千瓦的VX-200发动机,首次通过了200千瓦大关。

  艾德·阿斯特拉火箭公司是由美国前宇航员张福林(Franklin Chang-Diaz)在2005年创建的。他说:“这是当前世界上功率最强大的等离子体火箭。” VASIMR发动机眼下最大的竞争对手是美宇航局50千瓦“霍尔”发动机。“霍尔”发动机采用通过电子加速的带电原子或离子。不过,由于预算削减,美宇航局在2005年停止开发这种发动机。

  艾德·阿斯特拉火箭公司已与美宇航局签署协议,2013年在国际空间站测试200千瓦VASIMR发动机。另外,该公司还在同两家私营太空公司SpaceX和“轨道科学”谈判,希望借助其中一家的运载火箭将VASIMR发动机发射到国际空间站。如果一切顺利,艾德·阿斯特拉火箭公司希望从明年开始,根据商业合同定期提升国际空间站运行轨道。

  当前,包括俄罗斯和欧洲货运飞船在内的航天器是在同国际空间站对接期间,通过点着发动机提供这种推动力的。但是,使用常规推进器,每年会消耗7.5吨推进剂。张福林称,VASIMR发动机完成这项任务每年仅需0.3吨氩气,由于将燃料发射到轨道耗资巨大,这样一来,每年便可节省数百万美元。

  张福林在接受《新科学家》杂志采访时表示,因提升国际空间站轨道而获得的收入将帮助该公司“进一步完善这项技术,实现载人火星探测任务。”据张福林介绍,一台10到20兆瓦VASIMR发动机可以在39天内将宇航员送上火星,而常规火箭则需要六个月甚至更长时间。

  旅程缩短可以减少宇航员暴露于太空辐射的时间。否则的话,太空辐射将成为载人火星探测任务的一大障碍,特别是种种迹象表明,未来几十年太空辐射水平尤其高。张福林说,有朝一日,将人员和设备迅速送抵火星将成为该公司一个重要收入来源,“但眼下,我们的获利对象不是在火星,而是在地球。”(杨孝文)
hkhtg090201 发表于 2009-10-13 17:19 | 显示全部楼层
本帖最后由 hkhtg090201 于 2009-10-13 17:45 编辑
美测试世界动力最强劲离子发动机
2009年10月13日 00:04  新浪科技

  新浪科技讯 北京时间10月13日消息,据英国《新科学家》杂志报道,美国一家公司日前对一台满负荷运转的新型离子发动机进行了测试,使得我们 ...
hkhtg090201 发表于 2009-10-13 17:17

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有偿ISS轨道维持,这回证实了。
ps:2008年‘联盟’返回连续两次不正常,俄罗斯曾怀疑是空间站周围环境(电磁?)干扰造成,这回若把离子推进器放到联盟的上风方,是否影响俄罗斯呢?
hkhtg090201 发表于 2009-11-24 18:27 | 显示全部楼层
美科学家研制等离子火箭或将缩短前往火星时间2009年11月24日 14:02  新浪科技

美国科学家研制造等离子火箭


等离子驱动的VX-200


  新浪科技讯 北京时间11月24日消息,据《环球邮报》报道,前美国宇航员张福林(Franklin Chang-Diaz)对他的火箭抱有很高的期望,希望它能成为一名“外太空信使”、清除轨道碎片的垃圾车、最终前往火星的交通工具。这位在哥斯达黎加出生的物理学家认为,将来人类会全部搬迁到外太空,我们可爱的地球将变成一个“受保护的公园”。
  大大缩短前往火星的时间
  张福林现任艾德·阿斯特拉火箭公司(Ad Astra Rocket Company)总裁和CEO。他表示:“未来,我们的重孙们可以经常从他们的新居住地回到(地球),看一看他们的祖先生活的地方和他们祖先的文化诞生地。”
  很多人可能都认为这种想法太怪诞,根本经不起实际考验。但是张福林已经摘掉他的太空头盔,着手进行这方面的研究。如果让他的梦想变成现实的话,那么,他认为在他有生之年,人类将会利用他公司的创新性火箭,在银河系遨游。
  他表示,他的等离子火箭还有很多其他实际用途。这种被称作全功率可变比冲的磁等离子火箭(Variable-specific-impulse magnetoplasma rocket,VASIMR)采用的是美国宇航局曾经研究过的高功率技术(high-power technology)。这种火箭利用太阳附近的高温气体作为推进剂,因此将大大缩短它从地球前往火星所需的时间,从大约8个月缩短到仅仅39天。
  这种火箭还将把太空旅行的成本缩减一半以上、掀起航空航天业革命、为更多国家(包括他的祖国哥斯达黎加)的太空探索活动铺平道路。他打算使等离子推进器VX-200逐渐发展成可以在国际空间站上使用的火箭。今年9月,该火箭在地球上达到新的转折点。在一项试验过程中,发送机的功率超过了200千瓦,使它成为目前世界上最强大的电火箭。
  打算作为商用火箭
  在地球上进行的试验结束后,艾德·阿斯特拉火箭公司目前正在跟美国宇航局合作,打算在2013年把全功率可变比冲的磁等离子火箭发射到国际空间站。张福林表示,最终他的这项技术将被用来确保空间站位于既定轨道。
  该公司打算在2014年发射这种商用火箭。这听起来似乎比科幻小说还离奇,但是航天领域目前已经开始关注张福林的工作。最近美国航空航天学会(AIAA)指定全功率可变比冲的磁等离子体火箭是2009年出现的十大航天技术之一。
  在实施火星任务之前,张福林提出了这种火箭在地球附近的一些实际用途。例如它在外太空可以充当敦豪速递公司一样的角色,等离子推进器飞船会以更低的价格把包裹、主要燃料运往人造卫星或飞船。据张福林说,现在的货运费超过10亿美元,如果照此计算,艾德·阿斯特拉火箭公司的飞船大约需要5亿美元运费。他还提到另一种应用途径:飞往更靠近他祖国的心脏地带。用这些船只清理废弃人造卫星留下的太空碎片。
  地球就像一个大蜂窝
  张福林说:“事实上地球已经变成一个蜂窝。大量人造卫星围绕地球运行。我们正在讨论无数这种天体。其中一些只是漂浮在太空里的垃圾,因为这些人造卫星耗尽了燃料,它们不再运行,不过仍停留在轨道里。”废弃太空天体相互撞击,或者与我们的地球撞在一起。“你认为你看到的是美丽的流星,但事实上它们是来自地球的轨道垃圾,最终会在大气层里燃烧掉。”
  张福林表示:“我们的目标是拥有一辆‘垃圾车’,用来清除不同轨道里的这种天体。这种工作显然很有意义。”艾德·阿斯特拉火箭公司把这些碎片抛入“轨道墓地”,“或者我们把它们抛向太阳,让它们朝着太阳前进,奔向最终的宇宙垃圾场。”
  跟常规化学火箭不同,这种火箭把氩转变成等离子体,这是第四种物质状态,人们经常会在每天发生的闪电、温度极高的火焰、星云、太阳和其他恒星里发现等离子体。当然,这种物质温度很高,人类几乎无法应对它们。
  张福林解释说:“目前没有任何一种已知材料可以承受如此高温。因此我们不用原料,而是利用非常奇特的力生成这种无形的管道,使等离子体在无形管道内部达到极高温度。这种力是由非常先进的永磁发电机产生的。”
  等离子火箭的研制者
  也许大部分美国人都不知道张福林,但是在他的祖国哥斯达黎加,他是家喻户晓的知名人物。因为该国除他以外,没有一个人曾进入天空。张福林在1980年进入美国宇航局后,曾7次搭乘航天飞机进入太空。他在2005年成立艾德·阿斯特拉火箭公司以前,还曾担任美国宇航局先进太空推进实验室(Advanced Space Propulsion Laboratory)主管。
  他的成功来之不易。1968年他迁移18次,张福林在越战失败和祖国的种族战争进行的如火如荼之时,来到美国。虽然由于他拥有部分中国血统,小时候在哥斯达黎加经常受到嘲弄,但是他表示,这根本无法与他之后在美国受到的歧视相提并论。
  张福林说:“虽然美国存在很多动乱、歧视和社会斗争,但是我看到一个天生具有自我疗伤能力的国家,这是我在拉丁美洲的其他国家都不曾看到的。”他表示,他的一些成功机会来自于民权运动取得的进展。张福林在康涅狄格州哈特福德完成中学学业后,他从康涅狄格大学获得机械工程学位,然后进入麻省理工学院,并于1977年获得应用等粒子物理学博士学位,同年成为美国公民。
  他经常往来于德克萨斯州和哥斯达黎加的艾德·阿斯特拉火箭公司实验室。但是他在祖国建设的企业存在一个特殊弱点。他说:“回到了祖国就像久别回家,有种经过长途旅行重新归来的感觉。”他表示,他可以在瓜纳卡斯特(Guanacaste)的丛林中建造一枚火箭。(孝文)
 楼主| cmj9808 发表于 2010-1-30 12:45 | 显示全部楼层
NASA约翰逊宇航中心与Ad Astra 展开合作
NASA JSC Solicitation: Variable Specific Impulse Magento-Plasma Rocket - VASIMR

Date Released: Friday, January 29, 2010
Source: Johnson Space Center

NASA/JSC has a requirement for the acquisition of services to update a magnet fixture with an additional cryocooler for conduction cooling and to eliminate the liquid cyrogen cooling system in preparation for crycooler testing in vacuum and magnetic field combined environments. In addition, Studies will be conducted to evaluate a Lunar Tug concept utilizing Variable Specific Impulse Magneto-plasma Rocket (VASIMR) engine capabilities from Low Earth Orbit to Lunar Orbit and libration points.

NASA/JSC intends to purchase these services from Ad Astra Rocket Company. This is made pursuant to FAR 6.302-1 for the acquisition of supplies and services determined to be reasonably available from only one source. Ad Astra Rocket Company holds the exclusive right to develop VASIMR technologies under NASA patent applications. Adequate relevant cooling of the High Temperature Superconducting(HTSC) magnets require the conversion of the original HTSC magnet facility to utilize space-relevant cryo-cooler technology that has not yet been utilized under conditions that are relevant to VASIMR operation in space. Ad Astra Rocket Company uniquely possesses the patent rights and institutional memory necessary to make this test fixture relevant to VASIMR technologies.

The Government does not intend to acquire a commercial item using FAR Part 12. See Note 26.

Interested organizations may submit their capabilities and qualifications to perform the effort in writing to the identified point of contact not later than 4:30 p.m. local time on February 8, 2010. Such capabilities/qualifications will be evaluated solely for the purpose of determining whether or not to conduct this procurement on a competitive basis. A determination by the Government not to compete this proposed effort on a full and open competition basis, based upon responses to this notice, is solely within the discretion of the government.

Oral communications are not acceptable in response to this notice.

All responsible sources may submit an offer which shall be considered by the agency.

An Ombudsman has been appointed. See NASA Specific Note "B".

Any referenced notes may be viewed at the following URLs linked below.
snowtiger 发表于 2010-1-30 18:39 | 显示全部楼层


借这贴的宝地请教一下,这篇文章所说的是不是霍尔效应推进器?国内这方面的研究怎么样了?

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 楼主| cmj9808 发表于 2010-1-31 18:45 | 显示全部楼层
不是霍尔效应推进器
详见39楼◎ http://www.9ifly.cn/sub/thread-342-2-1.html
heito 发表于 2010-3-2 08:17 | 显示全部楼层

新型火箭速度达55公里/秒 39天完成火星旅行

2010年03月02日07:11腾讯科技编译/悠悠我要评论(0) 字号:

[导读]目前,美国火箭科学家最新研究表明,一种叫做“可变特殊推动力磁等离子体火箭”可达到55公里/秒的飞行速度,使地球至火星的航程仅需39天。
腾讯科技讯(编译/悠悠)据国外媒体报道,日前,一位火箭科学家最新研究显示,采用新型燃料技术可将地球至火星旅行的时间缩短至39天,这是之前地球火箭航行时间的六分之一。同时,这项最新技术也得到了美国宇航局高度重视。

未来火星旅行的时间可缩短至39天

美国麻省理工学院物理学家弗兰克林-常-迪亚兹(Franklin Chang-Diaz)曾是一位宇航员,他指出,使用高科技技术的VASIMR火箭可显著加快抵达火星的速度,这项技术已经过数十年的研发过程。

VASIMR火箭的全称是“可变特殊推动力磁等离子体火箭”,这项能够很大程度地削减太空探索成本的技术将很快被美国宇航局所采纳。目前,美国宇航局仍在犹豫是否应当取消“星座”计划,该航天计划将在未来十年内实现人类往返月球之旅,美国宇航局正在寻找新的技术促进未来的有人驾驶航天飞行。

迪亚兹所在的德克萨斯州阿斯特拉火箭公司为美国宇航局带来了新的希望,他在接受法新社记者采访时说:“最初美国宇航局对这项技术并不太重视,那是由于当时他们没有像现在强调先进航天燃料技术的发展和应用。”

今年60岁的迪亚兹希望这种非化学燃料火箭最终将实现宇航员驾驶航天器抵达火星表面,他设计的航天火箭采用电流转换氢气、氦气或氘气,加热至1100万摄氏度转换成为等离子气体。通过磁场将这些等离子气体导入排气管中,从而推动航天器飞行。预计采用该火箭燃料将使航天器达到55公里/秒的飞行速度。

据悉,迪亚兹具有7次航天飞行经验,他指出基于这种燃料技术可实现火星之旅仅需39天,相比之下,当前往返火箭需要3年时间,其中包含在火星上被迫停留18个月。

地球和火星之间的距离为5500万-4亿公里(依据近日轨道的远近距离),此外使用等离子燃料可使航天器周围形成一个磁场,可避免太空放射线辐射。目前,美国宇航局按比例缩小设计的VASIMR火箭已在真空环境中进行了测试飞行。

迪亚兹称,下一步将于2013年末设计一款采用200千瓦VASIMR发动机的VX-200航天器进行地球轨道部署。他认为SpaceX和轨道科学公司今后能够采用这种新型燃料技术。

尽管当前存在一些困难,迪亚兹坚信自己的这项最新技术具有广阔的市场前景,适合于维护和修理人造卫星,向火星发射遥控机械装置和商业任务。
rottenweed 发表于 2010-3-2 09:46 | 显示全部楼层
化学推进目前无可取代,主要还是因为推力问题。
200千瓦对应的推力太小了,即使比冲高10倍也太小。对应一下,现有的地面级火箭发动机的功率是可以达到千万千瓦级的,比三峡电站小不了多少。
cococo 发表于 2010-3-2 11:13 | 显示全部楼层
弗兰克林-常-迪亚兹!只要腾讯编辑中有一个人对航天有点认识,就不会搞出这么雷的名字。其实就三个字:张福林,第二位进入太空的华裔人士,第一位职业华裔宇航员。
snowtiger 发表于 2010-3-2 11:42 | 显示全部楼层
VASMIR,磁致可变比冲等离子体发动机。话说兆瓦级别电功率航天核反应堆搞出来就有希望把这东西做大达到满意的推力和比冲了。、。。。。
parifindo 发表于 2010-3-2 11:47 | 显示全部楼层
只要两个月吗,那么大大降低了登录火星的物资补给要求,如果这种理论能够实现应用,那太阳系殖民就越来越近了
tianlan 发表于 2010-3-2 18:07 | 显示全部楼层
本帖最后由 tianlan 于 2010-3-3 08:59 编辑

不知道他是怎么计算的,感觉不是很靠谱!
要达到55km/s的速度,需要多少时间呢?反正这个速度很惊人!当然这类发动机的比冲可是高的惊人啊!羡慕ing
 楼主| cmj9808 发表于 2010-3-2 19:44 | 显示全部楼层
下面这个帖子17-18#有具体介绍
http://www.9ifly.cn/sub/thread-1427-1-1.html
jingyan66 发表于 2010-3-8 21:03 | 显示全部楼层

超级火箭可让飞船达秒速55千米

2010年03月08日   现代快报

  美国麻省理工学院华裔物理学家、火箭科学家和前任宇航员张福林近日宣称,采用最新科技的VASIMR火箭,未来从地球到火星的旅行只需要39天。这一时间只是目前地球到火星飞行所需时间的六分之一。

  现年60岁的张福林表示,VASIMR火箭的全称是可变比冲磁等离子体火箭。其工作原理是利用电流将诸如氢、氦或氘等燃料转化为等离子气体。这些等离子气体被加热到1100万摄氏度后,磁场会将其引导进入排气管,从而推动太空飞船的飞行。在这种火箭的推动下,飞往火星或月球的航天器最高速度将可达到每秒55公里。

  作为一名曾经执行过7次太空任务的老牌宇航员,张福林认为,这一加速度将使得从地球飞往火星的旅行时间缩短为39天,而目前预测的往返火星的旅程则需要大约3年时间,其中包括被迫在火星上停留的18个月时间。地球与火星之间的距离大约为5500万公里到4亿公里,这要根据它们所处的轨道位置而定。

  使用等离子燃料还有另外一个好处,那就是可以在航天器周围形成一个磁场,使得航天器不会受到辐射。目前,科学家们已经制造出一个缩小比例的VASIMR航天器,并在真空环境中进行了测试。 (彬彬)
hkhtg090201 发表于 2010-5-5 22:28 | 显示全部楼层
等离子火箭可能缩短太空航行时间

新闻发布时间:2010-05-05


 可变比冲磁等离子火箭

  [据今日航天网2010年5月4日报道] 美国一家私营公司正在建造用于国际空间站飞行的创新型等离子火箭,其备份可能将执行自己的任务——造访行星。
  
  等离子火箭简介
  
  等离子火箭全名为“可变比冲磁等离子火箭”(VASIMR),具有一个电子推进系统,将来可使飞往火星的时间缩短至39-45天——利用常规化学火箭需要6至9个月。航行时间的减少降低了宇航员暴露在危机四伏的宇宙中和太阳辐射下的时间。
  
  飞往行星将有力地验证VASIMR技术,这项技术利用无线电波电离氩、氙或氢等推进剂,之后将电离区加热至20倍,达到太阳表面还高的温度。在控制方向的排气金属喷嘴处,VASIMR使用磁场。
  
  VASIMR火箭的发明者张福林 (Franklin Chang-Diaz)曾为宇航员,2005年离开NASA创立Astra火箭公司全力研制等离子火箭。VASIMR技术2009年在真空室成功进行了全功率验证。
  
  Astra公司计划2014年向空间站运送VASIMR型火箭。作为备份,张福林希望生产两台VASIMR,以避免发射事故或其他重大问题影响首次对空间站的发射。一旦发动机被安全地安装到空间站外,另一台VASIMR就可以执行一项新任务,并且不需要NASA的投资。
  
  未来发展构想
  
  一种构想是VASIMR发动机从空间站外部提供动力,另一个VASIMR执行小行星任务。NASA和Astra公司将与国防预先计划研究局(DARPA)组成团队利用VASIMR的高效性,目前在研的还有200千瓦的太阳动力帆板。火箭抵达目标行星后,太阳动力帆板还能为科学设备和其他仪器提供动力。张福林称,VASIMR火箭不需要动力系统,登上小行星之后关闭发动机,还有200瓦的能量用于执行任务。
  
  任务也可以进行雷达成像和观测,选择样本发回地球。 这项任务与美国总统奥巴马的太空新方向也相符合。VASIMR小行星任务是NASA研究团队目前评估的若干项提议之一。如果被NASA选中,这项任务到2017年可以实现自由太空飞行。 (中国航天工程咨询中心 侯丹 陈菲)

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hkhtg090201 发表于 2010-6-2 06:44 | 显示全部楼层
本帖最后由 hkhtg090201 于 2010-6-2 06:51 编辑

离子发动机能够 大幅改变 太空运输 方式

Plasma rocket could revolutionize space travel
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: June 1, 2010


The headquarters of Ad Astra Rocket Co. doesn't catch the eye, at least until you step inside.

Inside an unsuspecting warehouse in suburban Houston, hidden behind a streetcorner strip mall, a team of elite engineers and enterprising physicists is busy developing a high-tech plasma rocket designed to carry humanity to the stars.

Founded in 2005, the company accomplishes most of its work just a few minutes from Johnson Space Center, the home of Mission Control.

The company's main project is the Variable Specific Impulse Magnetoplasma Rocket, or VASIMR, a highly-efficient space engine running on electricity and argon gas instead of conventional solid or liquid propellants.

Franklin Chang-Diaz, the project's chief architect, says the VASIMR engine is the most flight-ready high-power electric propulsion system anywhere in the world.

"It is transformational technology that we are developing," Chang-Diaz said. "It always has been my view that chemical approach to space transportation really was not going to get us very far."



The VASIMR ground engine fires during testing in May. Credit: Stephen Clark/Spaceflight Now


Chemical rocket engines require spacecraft to carry all of its propellant during its mission. The VASIMR engine burns small amounts of argon gas, one of the most stable elements on the periodic table. But one of the most revolutionary features of the VASIMR design is its reliance on electricity, a renewable resource in space.

"It's very robust, but in order to get beyond the moon, and move on to Mars and beyond, we really need completely new transportation technology," Chang-Diaz said. "We view the VASIMR as the workhorse for that transportation infrastructure."

Electrically-powered plasma rockets could cut travel times for missions across the solar system. One concept championed by Chang-Diaz involves a 39-day mission to Mars, but it assumes leaps in nuclear energy production in space.

Originally bankrolled by NASA, the VASIMR project has gone from the drawing board to reality since the plasma rocket research was privatized in 2005. Inside Ad Astra's laboratories in Houston and Costa Rica, rocket designers have pushed the VASIMR engine closer to flight.

"In five years, we've made some pretty big jumps, in terms of power capability and the efficiency of the plasma source," said Tim Glover, Ad Astra's director of development.

NASA measures emerging technologies on a readiness scale from 1 to 10.

"When the technology is ready to fly is when you get to a level 6," Chang-Diaz said. "Level 7 is the actual flight."

The VASIMR engine is already at level 6, according to Chang-Diaz, who has worked on plasma rocket technology since the 1970s.

"I always felt there was a way to use that high-temperature plasma to develop a rocket engine that could go a lot faster than the rockets that we have today," Chang-Diaz said.

But Chang-Diaz was sidetracked by a second career as an astronaut after his selection by NASA in 1980. The 60-year-old is one of only two space fliers to complete seven missions on the final frontier.

In between training for space shuttle missions, Chang-Diaz led plasma research first at the Massachusetts Institute of Technology, then at NASA's Johnson Space Center.

But NASA decided to cancel advanced propulsion research to pay for the Constellation program to return humans to the moon, forcing the work into the private sector in 2005.

"Facing such dire possibilities on our project, I proposed to NASA that we privatize it," Chang-Diaz said. "Much to my amazement, they agreed that it would be a good idea. That's how Ad Astra Rocket Co. was born, out of a privatization agreement with NASA, where the laboratory that I used to lead was transformed into a private entity."

Chang-Diaz secured investments from the United States, Europe and his native Costa Rica summing several tens of millions of dollars, a figure he says is ten times more than NASA ever spent on the project. The company now employs about 40 workers in Houston and Costa Rica.

The influx of funding has propelled the VASIMR engine from a readiness level of 2 to 6 since the laboratory was privatized.

"That happened in five years, and we only got from 0 to 2 in 25 years," Chang-Diaz said. "It's been a very drastic progress in the last five years. That's what happens when you have money."

But the Obama administration's proposal to cancel the Constellation program and refocus NASA on nurturing new technologies for solar system exploration has put VASIMR in the limelight.

"President Obama has decided that NASA needs to go back to its roots and continue to fund projects of advanced technology," Chang-Diaz said. "We've almost come full circle, and we find ourselves at the point where NASA is interested again."


A diagram of the VASIMR engine. From right to left, the argon gas is injected into the engine, the gas is ionized in the engine's first stage, super-heated in the second stage, then directed through the nozzle by superconducting magnets. Credit: NASA


And Chang-Diaz's cozy friendship with NASA chief Charles Bolden doesn't hurt either, Glover said.

Chang-Diaz flew with Bolden on two shuttle flights and remain close friends today.

"Charlie and I are very good friends," Chang-Diaz said. "I think he's got the right approach in bringing people together. He certainly has the right personality and the right level of technical knowledge."

Bolden has cited VASIMR as an example of the new technologies NASA should be pursuing.

"One thing that will help will be to let somebody like Dr. Franklin Chang-Diaz or somebody who's studying ion engines help us develop a game-changing interplanetary engine that will cut the time to go to Mars in half," Bolden said in a news conference earlier this year.

Ad Astra officials say they welcome NASA interest in the project, but they insist on continuing the engine's development in the private sector.

"I don't want to put NASA in the critical path because you never know what's going to happen with NASA," Chang-Diaz said. "I wouldn't consider it very reliable at this moment."

Ad Astra is currently testing a two-stage ground version of the VASIMR engine inside a vacuum chamber in Houston. The 200-kilowatt engine, called the VX-200, looks nothing like a conventional rocket engine. The powerplant lacks the combustion chamber found on contemporary boosters.

The company successfully tested the ground engine to its 200-kilowatt design standard in late 2009, but those power levels were only achieved in short bursts lasting just a fraction of a second.

Engineers plan more testing of the VX-200 to eventually accomplish longer firings.

Ground testing so far has relied on low-temperature superconducting coils, but more ambitious demonstrations in space will use more durable materials capable of withstanding much higher temperatures and longer burn durations.

"The high-temperature superconducting tape is an enabling technology to us," Glover said.

Plasma inside the VASIMR engine is constrained by the powerful coils of a superconducting magnet, a key technological breakthrough that binds the engine together by accelerating the super-heated plasma to produce propulsive force.

The engine's argon fuel first passes through the assembly's first stage, where the gas is ionized as electrons are stripped from argon atoms. The first stage, also called the helicon section, heats the gas to about 10,000 Kelvin, or 17,540 degrees Fahrenheit, said Jared Squire, Ad Astra's director of research.

"It's the same thing you do in a steam engine, where you first boil water to make steam," Squire said. "You're heating the gas, and that's where the plasma is formed."

The VASIMR engine's second stage applies more electromagnetic power to the plasma in a process called ion cyclotron heating. The plasma spills out of the engine nozzle at more than 110,000 mph. The exhaust can reach temperatures of up to 1.8 million degrees Fahrenheit, according to Squire.

Officials plan to work out the kinks in the technology before launching flight engines to the International Space Station by 2014 for an orbital demo. Glover said the station tests will use two engines operating at 100 kilowatts.

The 10,000-pound engine package will be launched on one of the commercial cargo carriers being developed by SpaceX and Orbital Sciences.

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hkhtg090201 发表于 2010-6-2 06:45 | 显示全部楼层
本帖最后由 hkhtg090201 于 2010-6-2 06:52 编辑


An early concept of the VASIMR engine on the International Space Station. Credit: NASA


VASIMR's opportunity to fly on the space station came through a Space Act Agreement signed with NASA in 2008. The contract, which does not include an exchange of funds, stipulates Ad Astra and NASA must pass through five milestones before the test flight.

The parties already completed a payload integration agreement, and the next step will be the VASIMR engine's preliminary design review in 2011.

Ad Astra hopes the VASIMR engine could be used to reboost the space station after it completes its demonstration objectives.

"If the ISS is really extended well into the 2020s, then the international partners might agree they would like to do reboost using electric propulsion," Glover said. "You would likely have to wait until present agreements to do reboost with [Europe and Russia] are ending, then you could say Ad Astra has already demonstrated this system on the ISS. Why don't we consider how much money we could save by moving this back and using it for reboost?"

Glover said such a move would save the station program $200 million and 7 metric tons of propellant each year. That money and mass could be diverted for other scientific experiments aboard the complex.

But Ad Astra has set its sights even higher than Earth orbit. The company believes the VASIMR will make voyages to Mars and asteroids a reality.

It just so happens those places are the new destinations for NASA's human exploration plans, which would bypass the moon, for now.

"We have to get to Mars fast," Chang-Diaz said. "It can't take six, or seven, or eight months to get to Mars. That is just asking for trouble."

Even if chemical rockets get humans to Mars, the program will be unsustainable because of the lengthy journey and high cost, according to Chang-Diaz.

"These engines that we're developing are inherently high-power engines. These aren't little thrusters, these are very powerful engines, which can scale up to tens of megawatts," Chang-Diaz said.

Those megawatt-class engines will be required for any substantial presence in the solar system. The 200-kilowatt engine now under development is best suited for work in Earth orbit or in multi-engine clusters.

But is a 39-day manned trip to Mars really possible? Ad Astra says yes, with caveats. It would require major advancements in nuclear power and a departure point somewhere high above Earth.


Ad Astra's concept for a VASIMR-powered spacecraft on the way to Mars. Credit: Ad Astra


"The ship for a 39-day mission to Mars is not that much different than a 747 jumbo jet, in terms of power," Chang-Diaz said. "When they hear we want to use a 200-megawatt ship to go to Mars, people cringe and wring their hands, and say how are you going to get that much power?"

Current technology can't produce enough electricity in space to drive multiple megawatt-class high-power plasma engines for weeks at a time.

"That takes a really lightweight power supply, around 1 kilogram per kilowatt, which is probably ultimately doable," Glover said.

According to Glover, the most important measure for the efficiency of plasma engines is the weight-to-power ratio, or the number of kilograms needed to generate a kilowatt of electricity.

Flat panel solar arrays today have a ratio of about 20 kilograms, or 44 pounds, for every kilowatt of power they produce. The best nuclear reactors designed for spaceflight have a specific mass of about 45 kilograms, or nearly 100 pounds.

The Pentagon and Boeing Co. are developing a next-generation solar array aimed at reaching a weight-to-power ratio of 7 kilograms per kilowatt, according to the Defense Advanced Research Projects Agency.

Engineers predict nuclear power generators will reach an efficiency of a few kilograms per kilowatt within a couple of decades.

Even if 39-day trips to Mars are still a distant dream, Ad Astra officials are confident the journey time for smaller missions can be cut by more than half by the 2020s with imminent breakthroughs in solar array technology.

"While solar technology is very impressive and it can be used to do some technology demonstrations soon, it's not going to get us very far. Ultimately, you need to have nuclear power if you want to do big things out there."

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hkhtg090201 发表于 2010-6-18 17:51 | 显示全部楼层
Vasimr取得新的一步。 PS:不知道新在那里
Vasimr Prototype Makes New Strides

Jun 16, 2010
  
By Mark Carreau


HOUSTON — Ad Astra Rocket Co., led by former NASA astronaut Franklin Chang-Diaz, reports new strides in the performance of its experimental 200-kw. Variable Specific Impulse Magneto-plasma Rocket (Vasimr), the VX-200, which the company is developing as a commercial propulsion source for a range of future deep space and possible near-Earth missions.

The company, headquartered near NASA’s Johnson Space Center in Houston, intends to make use of the International Space Station’s national laboratory status to place a two-stage prototype, the VF-200-1, on the orbiting laboratory for propulsion testing in mid-2014 (Aerospace DAILY, April 19).

Earlier this week, Ad Astra completed a six-month round of testing in which it dramatically improved the timing and performance of the startup of the VX-200’s 30-kw. first stage. Other testing in the company’s large vacuum chamber verified efficiencies of greater than 50% in the conversion of electricity to thrust through 112 kw., with combined first- and second-stage operations.

The company’s engineers plan to resume efficiency testing later this year, Chang-Diaz says.

Last fall, the VX-200 Vasimr prototype reached full-power plasma thrust under the control of a superconducting magnet in vacuum conditions. The achievement marked a critical milestone in Chang-Diaz’s long-running efforts to develop an electric propulsion drive that could one day transport humans to Mars in 39 days.

During follow-on testing over the first six months of this year, Ad Astra reduced the first-stage startup time from 6 sec. to 60 millisec. At the same time, engineers improved the success rate of the ignition process from 50% to 99% through characterizations of the electronic circuitry and software adjustments.

The latest round of testing mapped the efficiency of dual-stage operations through 112 kw. at 55%, closely matching predictions. “Anything over 50 percent is good,” Chang-Diaz says.

The efficiency predictions climb to 60% at 200 kw., or full thrust.

Meanwhile, Ad Astra continues to explore a range of missions for an operational Vasimr. The company has already previewed plans to use a backup to the VF-200-1 for a mission to a yet-to-be-specified asteroid. It also has developed concepts for a tug to cycle cargos between Earth and lunar orbit as well as a spacecraft that could grab and de-orbit aging satellites that have depleted their fuel.
 楼主| cmj9808 发表于 2010-6-18 18:41 | 显示全部楼层
回复 38# hkhtg090201

启动时间缩小至60ms;点火成功率增加至99%;效率增至55%@112kW
hkhtg090201 发表于 2010-7-13 20:50 | 显示全部楼层
Additional Space Shuttle Flight Could Include VASIMR Test
附加的航天飞机飞行可能包括 VASIMR测试。

Posted by Doug Messieron July 12, 2010,


     NASASpaceflight.com has details of an additional space shuttle mission that could be flown next June by Atlantis. A four-member crew would fly the ship to the International Space Station with additional supplies and equipment, possibly including a prototype plasma engine.


The website reports:

Those payloads will be decided over the coming weeks, likely as part of the approval decision – although the late June 2011 flight may allow for launching the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) engine - providing it can support its original scheduled – which is questionable. VASIMR would be tested by aiding the ISS altitude control – such as reboosts.

The engine – otherwise know as an Electro-thermal Plasma Thruster or Electro-thermal Magnetoplasma engine – uses radio waves to ionize and to heat propellant and magnetic fields to accelerate the resulting plasma to generate thrust.

However, due to the power requirements at the ISS, the engine will only be put through minimal testing. Several other working assumptions are also pre-empted for the notional mission, which will undergo evaluation during Monday’s meeting.

There will be no backup shuttle available for a rescue mission, so the assumption is that the four-member crew will be able to find safe haven at ISS until they can be returned to Earth via Russian transports.

It was also noted – as expected – that STS-135 would fly with a minimum of four crew, allowing for a dual-Soyuz LON [launch on notice] plan to be utilized in the highly unlikely event Atlantis received damage to the level she would not be able to bring the crew home.
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