NASA试图用机器人来救助哈勃使之重获新生

托尼·莱希哈特, 华盛顿

NASA正试图阻止它以前所做的重大决定以便不再让宇航员去维修哈勃太空望远镜而让机器人去从事这项工作。

来自产业实体和研究所的数十个团体已经对机构做出了反应，要求使用机器人宇宙飞船去替换望远镜的电池和陀螺仪，并安装两个新的科学装置。

这些工作曾经是由宇航员来完成的。但NASA 的首席科学家埃德·威勒(Ed Weiler)在上周告诉美国国家科学院的太空研究委员会说这不是信念的巨大跨越，即一项自动化的使命来延长哈勃的使用寿命是可能的。一个机器人能够替换望远镜的电池，电池大约能够用到2007年。

提交主意的截止日期是3月22日。虽然NASA还没有对这样一项任务提出正式的竞标请求，但是哈勃项目的执行官迈克尔·摩尔(Michael Moore)告诉委员会说：“我们事实上已经从那些有能力胜任此项工作的人那里得到了主意。”

科学院也组织了一个委员会来研究如何维修望远镜并延长其寿命。尽管从预算和政治角度考虑最好是把宇航员送回哈勃去完成此项任务，但是NASA的局长肖恩·奥基夫(Sean O’Keefe)宣称考虑到航天飞机的安全性不要这样。自从1990年的那次发射以来，航天飞机上的宇航员已经四次升级了望远镜。

洛克希德马丁(Lockheed Martin)公司当年建造了哈勃，现在它也是主张使用机器人的团体之一。布鲁斯·麦克坎德莱斯(Bruce McCandless)以前是一位宇航员，他曾经帮助设计了修理望远镜的程序，现在他是位于丹佛的洛克希德马丁公司的可重用太空运输系统的首席科学家，他说至少有三套正在开发的系统能够承担此项工作。其中的一套是由加拿大安大略省宾顿市的MD机器人技术公司制造的，该公司还制造宇宙飞船和空间站上的机械手。另一套是人形机器宇航员，位于休斯顿的NASA的约翰逊太空中心在研制该系统。第三套系统正由位于美国学院公园的马里兰大学太空系统实验室制造，该实验室是洛克希德马丁公司提案的一位伙伴。

马里兰的这套系统包含了像宇航员所使用的机械手轴承工具，并且已经在实验室和水下贮罐中进行了模拟失重测试。这是为今年的航天飞机测试飞行而设计的，但是在几年前空间站遭遇资金问题时，NASA削减了测试的资金。“我们已经完成了飞行机器人的70%，但现在只能锁在我的实验室中。” 领导马里兰项目的戴维·阿金(David Akin)抱怨道。

阿金和麦克坎德莱斯认为使用机器人和宇航员维修哈勃并不是科技上的大迈步。阿金指出虽然用机器人来完成全部工作更具有挑战性，花费的时间也更久，但是还是可以实现的。NASA可能会决定抛弃那些诸如增加新的装置之类的更具挑战性的任务。

由位于阿拉巴马州汉斯维尔的美国天空公司(SkyCorp)领导的团体建议用机器人把低推力火箭装到哈勃上面以便将它送回国际空间站由宇航员来对它进行维修。但是巴尔的摩的太空望远镜科学研究所的所长史蒂文·贝克卫斯(Steven Beckwith)告诉太空研究委员会他担心机器人维修方案在技术上是否已经就绪，并倾向于使用宇航员，尽管美国天空公司的丹尼斯·威哥(Dennis Wingo)反对使用宇航员，他说：“管理者已经做出决定。所以我们只能在以下两者之间折衷，即是让哈勃坠海还是让另外七位宇航员去冒险。”

威勒估计制造维修机器人将耗资不到三亿美元，即使外加火箭发射和别的技术开发，机器人维修也要比航天飞机飞行便宜。那可能是摆脱奥基夫的困境的极好方法，虽然对望远镜可能更冒险，但对宇航员却不是。

NASA seeks robotic rescuers to give Hubble extra lease of life

Tony Reichhardt, Washington

NASA is seeking to damp a firestorm over its decision to stop astronaut servicing of the Hubble Space Telescope by lining up ideas for robots that could do the job.

Dozens of teams from industry bodies and academic institutions have responded to an agency request for schemes to use a robotic spacecraft to replace the telescope's batteries and gyroscopes and install two new science instruments.

    These were traditionally jobs for astronauts. But NASA science chief Ed Weiler told the National Academies of Sciences' Space Studies Board last week that "it's not a big leap of faith" to imagine that an automated mission could extend the Hubble's working life. A robot could change the telescope's batteries, which are expected to run out of power around 2007.

    The deadline for submitting ideas was 22 March. NASA has not yet issued a formal request for bids on such a mission, but Hubble programme executive Michael Moore told the board: “We’re actually getting ideas from folks who can do things."

    The academy is also forming a committee to study how to service the telescope and extend its life. NASA administrator Sean O'Keefe has vowed not to send astronauts back to Hubble owing to safety concerns with the space shuttle — although critics charge that budgetary and political considerations have also swayed the decision. Shuttle crews have upgraded the telescope four times since its 1990 launch.

    Among the teams proposing a robotic mission is one from Lockheed Martin, which built Hubble. At least three systems in development could do the job, says Bruce McCandless, a former astronaut who helped design the procedures for servicing the telescope and is now chief scientist for reusable space transportation systems at Lockheed Martin in Denver. One is made by Canadian company MD Robotics of Brampton, Ontario, which also made the robot arms on the space shuttle and space station. Another is the anthropomorphic Robonaut under study at NASA's Johnson Space Center in Houston. The third is being built by the University of Maryland's Space Systems Laboratory in College Park, a partner in the Lockheed Martin proposal.

    The Maryland system, which includes robotic arms bearing tools like those used by astronauts, has been tested in the laboratory and in underwater tanks to simulate weightlessness. It was intended for a shuttle test flight this year, but NASA cut the test's funding when the space station hit financial trouble several years ago. "I've got pieces for 70% of a flight robot locked up in my lab right now," says David Akin, who leads the Maryland project.

    Using robots with astronauts on a Hubble repair would not be a big technical stretch, Akin and McCandless say. Having a robot do the whole job is more ambitious and would take longer, says Akin, but is still within reach. And NASA could decide to scrap the more challenging tasks, such as adding new instruments.

    Another team, led by SkyCorp of Huntsville, Alabama, has suggested sending up a robot mission to attach a low-thrust rocket to Hubble and bring it down to the International Space Station for servicing by astronauts. But Steven Beckwith, head of the Space Telescope Science Institute in Baltimore, told the Space Studies Board he was concerned about the technical readiness of any robotic servicing option, and preferred an astronaut mission. Dennis Wingo of SkyCorp believes this may no longer be an option, however. "The administrator has dug in his heels. So what we have is a compromise position between dropping Hubble in the ocean and risking another seven astronauts."

Weiler estimated that building the service robot would cost less than $300 million, and said that even with a rocket launch and other technology development thrown in, robotic servicing would still be cheaper than a shuttle mission. That may make it the perfect way out of O'Keefe's dilemma — it might be riskier for the telescope, but not for the astronauts.■