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[专题] 美国宇航局进入后“星座”时代:参议院勒令NASA重做重型火箭计划书

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 楼主| jingyan66 发表于 2008-11-24 13:08 | 显示全部楼层

美国公布“战神”新设计方案

2008年11月20日

  美国航宇局近日公布了将用于登月任务的战神5重型火箭的新设计方案。修改设计后,战神5的芯级氢氧发动机台数从5台增加到6台,捆绑助推器从5段式加大到5.5段式,火箭高度增加了6米,达到106米,运载能力有所增大。

  战神5的研制工作涉及NASA各中心和全美各地承包机构的多支硬件和推进组件研制队伍,由设在NASA马歇尔航天飞行中心的战神项目办公室牵头领导。这些队伍依靠NASA近半个世纪以来在航天飞行方面积累的经验以及航空航天技术所取得的进步。它们正在共同研制新的火箭设备和飞行系统,并使来自“土星”五号火箭及航天飞机推进组件的各项技术变得更加成熟。

  战神5火箭的首次试飞计划在2018年前后进行,而首次执行载人登月任务的时间则定在2020年前后。火箭的可复用固体火箭助推器主承包商为ATK发射系统公司,J-2X上面级发动机和RS-68B芯级发动机主承包商为普惠洛克达因公司。

《太空探索》杂志社供本网专稿
cmj9808 发表于 2008-11-24 20:23 | 显示全部楼层
RS-68B?RS-68A?
 楼主| jingyan66 发表于 2008-11-26 13:00 | 显示全部楼层

美国打造世界推力最强火箭 可送人上小行星

2008年11月26日

    据英国《新科学家》杂志网站报道,美国宇航局2007年曾委托美国国家研究委员会(NRC)对其拟研发的新型火箭项目进行评估。11月24日,美国国家研究委员会对规划中的这种火箭给予高度评价。根据设计,这种名为“战神5”的火箭是世界上迄今推力最大的火箭,不仅可以轻松地将宇航员送上月球,甚至还能将他们送上外太空的小行星。

    美国国家研究委员会公布的评估报告显示,美国宇航局规划中的新型火箭正式名称为“战神5”(Ares V),其载重能力超过目前世界上任何一种火箭和飞行器,预计将于2020年进行首次载人太空发射。根据设计,“战神5”一次可以将长度超过8米或者质量达到数十吨的物体送入太空,比如它可以将55吨重的物体直接送入距地球150万公里的外太空。美国宇航局内部认为,如果“战神5”的研制和进展顺利,他们届时就可以实现将宇航局送上外太空的小行星。这对于人类未来有效防止小行星撞击地球无疑具有极为重要的意义。但美国宇航局的科学家们担心,这枚准备取代航天飞机将美国宇航员重新送上月球的新型火箭可能会在起飞的头几分钟剧烈振动,极有可能会毁坏整个火箭。

    美国宇航局公布的“战神5”号火箭的最新设计方案显示,这枚将在12年内搭载宇航员到达月球表面的火箭大约有38层大楼那么高,而且载荷也超过了最初的计划。这枚火箭的长度比最初设计方案增加了大约20英尺,原计划火箭底部安装5个主发动机,现在变成了6个。工程师表示,他们还决定扩大一对固体燃料火箭助推器,这两个助推器将被安装在火箭侧面,这样它就能比最初预计携带更多燃料、补给和仪器。马歇尔航天飞行中心“战神”号项目办公室经理史蒂夫-库克表示,这个新方案大约将让“战神5”号比原设计多携带1.56万磅载荷。根据刚开始的设计方案,“战神5”号长361英尺,大小跟“土星5”号登月火箭类似。但库克表示,重新设计的“战神5”号火箭长381英尺,大约跟38层楼一般高。

    这枚火箭是美国宇航局“星座”月球探测项目的一部分,该火箭能携带4名宇航员、一个月球着陆器和其他将在月球上降落的仪器。美国宇航局表示,它希望“战神5”号总共能数万吨的货物运输到月球上,并且将来有一天可把人和货物送往火星。库克说:“我们已经参考了1700多个‘战神’号的设计方案。”有关人员在设计这套新方案时,权衡了成本、安全、可靠和性能等因素。经过为期9个月的研究,确定美国宇航局是否能实现重返月球的目标后,宣布了这项改进方案。“星座”计划项目经理杰夫-汉雷在声明中表示,研究显示,宇航员可在2020年重返月球。他说,“这项大规模研究证明我们已经为下一阶段做好准备,这个阶段是:采纳这些设计方案,继续前进。”

    美国宇航局表示,有关“战神5”号火箭的主要研究工作将在2010年航天飞机退役后展开。“星座”计划跟“阿波罗”计划不同,在“阿波罗”计划中,巨大的“土星5”号一次性将宇航员和所有仪器发射到太空,而“星座”计划制定了分两步将宇航员和仪器送入太空的方案。宇航员将搭乘一枚可以重复使用的火箭“战神1”号搭载的太空舱进入轨道。一旦到达那里,它将与一个由“战神5”号搭载的、环绕地球运行分离舱对接,然后与一颗登陆器、货物和补给一起前往月球。

    自2005年以来,美国宇航局一直致力于重返月球计划,总投资超过1000亿美元。这其中包括设计两种不同用途的火箭:将宇航员送入太空的“战神1”号和一种专门负责运送货物的火箭“战神5”号。研究人员担心的不是第一节的振动,而是它如何影响“坐”在上面的部分:“猎户座”宇航员座舱、工具舱和一个助推器。第一节火箭的技术借鉴自美国宇航局用来发射航天飞机的固体燃料火箭助推器的5个部分,将由犹他州布莱汉姆市ATK发射系统公司建造。
cmj9808 发表于 2008-12-10 18:51 | 显示全部楼层
Ares I Thrust Oscillation meetings conclude with encouraging data, changes
December 9th, 2008 by Chris Bergin

                               
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A series of Ares I Thrust Oscillation (TO) meetings have concluded with the decision to recommend baselining Ares I’s Tuned Mass Absorber (TMA) on the aft of the vehicle as a passive - as opposed to active - system, as the latest analysis - which has included human tests - reduce TO as a potential LOV/C (Loss of Vehicle and Crew) event to 1 in 150,000. Notes also reference that TO may not even affect Orion on two out of three launches, according to the latest computational data.

Also known as “Resonant Burning” - described as vortices that shed within the solid rocket motors during combustion due to the shearing of internal flow at propellant discontinuities - the issue relates to when the frequency of thrust oscillations is coincident with the acoustic modes of the motor cavity.

When pressure oscillations drive resonant modes in the vehicle structure, these oscillations are capable of rendering the astronauts incapacitated, or worse.

This was the major concern, that crew health was at risk during the few seconds TO occurs late in first stage flight. However, via recent engineering work that has created several options to mitigate TO on Ares I’s first stage reaching the crew seated in Orion, this risk has - it’s claimed - been eliminated.

This left engineers with the challenge of ensuring the mitigation techniques countered any potential issues of crew function - in other words, that TO would not hinder the crew from carrying out manual commands during the four to five seconds of a TO event during first stage.

Currently two engineering options have been baselined into the vehicle, with a third likely to be added during next year’s Ares I Delta PDR (Preliminary Design Review).

One is a set of “shock absorbers” that will be added to the aft skirt of Ares I. Known in some documentation as the Skirt TOA (Tuned Oscillating Arrays) Concept, but commonly known as the Tuned Mass Absorbers (TMA) concept, 16 actuators are placed around the circumference of the aft to counter the oscillations.

This was classed as an active system - one which would react to the oscillations as required, with the contingency of still being able to mitigate a large amount of TO, should one or more actuators failed.

This has since moved to a passive system, following the series of meetings that concluded last week.

Some engineers at the Marshall Space Flight Center (MSFC) are still arguing for an active system, with findings heading to NASA HQ this week for review by NASA administrator Mike Griffin, who is continuing to be ‘hands on’ with Ares I/Orion’s development.

The final decision will be important, due to the passive system holding less mass penalties on the vehicle than the active concept, along with an indication into the current level of confidence that TO is losing its footing as a major problem for Ares I.

The second area of mitigation is at the interstage are of Ares I.

This concept is called the SoftRide Isolator - a set of 200 brackets, weighing a total of two tons, that fit around the circumference of the joint between the frustum and interstage.

Notes of concern were raised a few months ago, relating to their ability to mitigate the oscillations as planned, and that they could exacerbate potential vehicle buckling at the interstage. This was know as “local bending moment due to load eccentricity”.

This led to a redesign of the isolators to “reduce or eliminate” that threat. Work is continuing on the design, though it remains baselined as one of the main elements of TO mitigation at this time.

The third option - which was deferred until 2009 in order to avoid a delay to August’s main PDR for Ares I - relates to isolating the crew seats from most of the remaining oscillations that could ride up the vehicle from the first stage.
This remains on the cards for being added to Orion in 2009, following its references in the latest meetings, which backs up the documentation from Orion’s Lockheed Martin engineers that the isolation ‘crate’ will become a “Change Request” in 2009 - which they complained was yet another change to the vehicle, causing problems with their wish to work with a stable design.

Notes from the meetings (listed on L2) make for interesting reading, with most of the previous engineering overviews showing wide-scale concerns about both the effect of TO on the vehicle, and issues with the planned mitigation techniques. Notes from previous meetings have almost been completely detached from the overly positive overviews given by Ares I managers at media briefings.

However, the latest meeting shows a sea change towards the positive, following an overview of analysis work that has been carried out over the last few months.

It is now understood that there is close to an engineering consensus that the combined mass absorbers on the aft, in combination with the interstage isolator are deemed as capable of “doing the job”.

That job is to ensure crew health remains within requirements when TO occurs during late first stage flight, and within the limits of crew function. The latest risk number of 1 in 150,000 relates to an incident where the crew have to carry out a manual function in Orion, during the five seconds of a TO event.

Engineers found that the only time a manual command would be required at this stage of flight would be via the need to manually abort the mission. Given the onboard computers handle such aborts, the manual command would only be required during a severe system failure - such as an automated failure of Orion’s flight computers - thus reducing the likelihood yet further.

“Evaluations on the ‘probabilistic’ analysis looked at the flight time sequence, and the probability that TO will occur,” notes from the meeting add. “(We) looked at the probability of what event will be likely to occur that would required the crew to react, to a potential abort scenario they have to respond manually. In the final analysis, most of tasks can be/will be done faster and more reliably by computer.”

The analysis also showed that TO may only “occur” - or affect Orion - once in every three flights. This in itself is a major finding, though there is a counter argument that claims that this points towards the computational models - known as “Monte Carlo runs” - suffering from inaccuracies.

On crew function, human tests were carried out on the ability of a crew member being able to carry out a manual function during a TO event. These tests have been carried out at NASA Ames, to determine “what is the TO ‘g’ level that the crew are unable to function at.”

This involved a “two group test”. One group consisted of 16 civilian volunteers with age matching the crew. The second group was made up of around six astronauts.

The crew member was tested in Ames’ centrifuge for 145 second to see if they can read displays on a mock up Orion computer readout - located an arm’s length away, at a font size of 2, 10, 14, whilst being put through simulated g force thrust oscillations.

The results showed that at 10 font, crew incurs reading error of 5 percent at 0.3g, and 10 percent at 1.0g, which added confidence that crew function would not be seriously hindered during various levels of expected TO post-mitigation.

The conclusion, based on this latest set of results, has reduced TO as a threat to the development of the Ares I vehicle to a rank of 35th of the risk matrix list. Previously it was consistently in the top three.

More work is required over the coming year, with a requirement to decipher data to see if engineers can separate g-load vs. time vs. frequency for more wide-ranging results. Additional crew test data will also be carried out as required.
Additionally, data is already being evaluated from STS-126’s boosters - which carried two new sets of instrumentation, aimed at gathering more detailed data on RSRM (Reusable Solid Rocket Motor) behaviour during the first stage of launch.

Ultimately, the first real data point engineers will have at their disposal will come via the test flight of the five segment Ares I-Y in 2011.

Additional data will be forthcoming in the interim period, with additional booster instrumentation flying on downstream shuttle flights, along with ATK RSRM test fires in Utah, and the four segment Ares I-X launch in either July or October, 09.

[ 本帖最后由 cmj9808 于 2008-12-10 18:54 编辑 ]
东方红 发表于 2008-12-11 10:16 | 显示全部楼层
抑制震荡、加强级间匹配、提高逃逸救生,战神一号火箭为了提高可靠性可说是不遗余力。老美载人航天死人最多,教训深刻,现在是慎之又慎。
 楼主| jingyan66 发表于 2008-12-11 16:36 | 显示全部楼层

NASA“战神”-5货运运载火箭规格及时间表

【据《国际空间》杂志2008年12月9日报道】2006年“战神”-5火箭正式命名,火箭能够将地面出发段(EDS)和“牵牛星”月球着陆器送入低地球轨道。

    NASA“战神”-5火箭由第一级和核心级组成,第一级由两个固体火箭助推器组成,核心级由六台普惠公司RS-68B发动机提供动力。

    火箭EDS采用普惠公司的J-2X发动机,它源自于“土星”火箭第二级的J-2发动机,J-2X发动机目前还处于研发阶段,还计划用于“战神”-1乘员运载火箭的上面级。

    这些发动机都采用液氧液氢燃料,燃料箱都采用铝锂合金。部分火箭元件将采用混合结构,如用于连接核心级和EDS的级间护罩,可能是圆锥型或尖顶型(弹头型)。

    “战神”-5火箭还可能采用乘员运载火箭、“牵牛星”和“猎户座”乘员探索飞行器的电子设备。

    该项目的时间节点如下:

                               
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 楼主| jingyan66 发表于 2008-12-12 12:21 | 显示全部楼层

“牵牛星”登月舱将于2018年6月搭乘“战神”V进行首次飞行试验

NASA considers June 2018 Altair Lunar Lander in-orbit trial


DATE:11/12/08
SOURCE:Flight International
By Rob Coppinger

NASA's Altair Lunar Lander could have its first test flight with in-orbit propulsion firings in June 2018 after being launched by the US space agency's Ares V cargo launch vehicle.

The Altair's launch would be on the Ares V's test flight, Ares V-Y, already targeted for June 2018. Once Altair is in its 242km (150 miles) low Earth orbit, to which the Ares V's Earth departure stage (EDS) is designed to push the lander, it would separate from the EDS.
牵牛星.JPG
Above: NASA's Altair Lunar Lander concept floats in space
If that separation was successful Altair could fire its descent stage's propulsion system. In a lunar mission Altair's descent stage will carry out lunar trajectory correction manoeuvres and the lunar orbit insertion burns.

Revealed in the NASA Ares project office's Ares V's pre-phase study, its report says: "Further study will be conducted to determine the feasibility of including a production Altair as a flight-test article and adding test objectives [of separation and propulsion]."

However, the assumption of NASA's Ares V mission concept review is that the Ares V-Y payload will be "a structural analogue" of Altair. NASA's schedule has the first operational Altair lunar mission in December 2019.

The last, and only, time NASA conducted a LEO lunar lander test flight was for Apollo 9. Launched from Kennedy Space Center's pad 39A on a Saturn V on 3 March 1969 at 11:00 local time into a 190km orbit, the 10-day mission saw its crew of three dock the command module to the lunar module, which was still attached to the Saturn V's S-IVB third stage.
 楼主| jingyan66 发表于 2008-12-12 12:25 | 显示全部楼层
原帖由 jingyan66 于 2008-12-12 12:21 发表
NASA considers June 2018 Altair Lunar Lander in-orbit trial

DATE:11/12/08
SOURCE:Flight International
By Rob Coppinger

NASA's Altair Lunar Lander could have its first test flight with in-orbi ...


刚贴完就发现中文译文已经出来了


NASA将于2018年6月在轨测试“牵牛星”月球着陆器


    【据《国际飞行》杂志2008年12月11日报道】NASA的“牵牛星”(Altair)月球着陆器计划于2018年6月进行首次在轨试飞。

    “牵牛星”将搭乘NASA“战神”-5-Y(Ares)发射。“牵牛星”着陆器进入242千米高的低地球轨道时,将与“战神”-5火箭负责推进着陆器的的地面出发段分离。成功分离后,“牵牛星”将点燃其下降段的推进系统。在月球任务中,“牵牛星”的下降段负责执行月球弹道修正的机动以及月球轨道插入。

    NASA“战神”项目办公室的“战神”-5前期研究显示,下一步将生产一台飞行试验用的“牵牛星”,并增加分离和推进的试验目标。NASA“战神”-5任务概念评审设想“战神”-5-Y有效载荷的结构与“牵牛星”类似。NASA计划于2019年12月实施首次“牵牛星”月球任务。
Nighthawk 发表于 2008-12-12 13:08 | 显示全部楼层
不知道战神1火箭的成本控制怎样,按理说飞船应该是比较便宜的,可没准老美又搞出一个史无前例地贵的系统来……看目前的进度,我觉得有这趋势
cmj9808 发表于 2008-12-12 13:51 | 显示全部楼层
原帖由 jingyan66 于 2008-12-12 12:25 发表


刚贴完就发现中文译文已经出来了


NASA将于2018年6月在轨测试“牵牛星”月球着陆器

    【据《国际飞行》杂志2008年12月11日报道】NASA的“牵牛星”(Altair)月球着陆器计划于2018年6月进行首次在轨试 ...

Orion-Altair的LOI是由Altair完成的,Apollo计划中则是由SM完成。再加上用太阳能板替换了燃料电池,难怪Orion比Apollo要少8-10吨
cmj9808 发表于 2008-12-12 14:06 | 显示全部楼层

关于Altair的几张图

内容比较杂,放在这里供各位参考
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 楼主| jingyan66 发表于 2008-12-16 16:03 | 显示全部楼层

NASA测试猎户座航电设备

2008-12-16

【据美国aviationweek网站2008年11月15日报道】NASA正在测试“猎户座”航电设备,并将其安装在“猎户座”乘员舱测试单元内,准备运往白沙靶场,进行发射中断系统测试。
cmj9808 发表于 2008-12-16 18:56 | 显示全部楼层

Obama reviews shuttle's finale(maybe bad news for constellation,maybe not)

奥巴马的团队可能会推迟航天飞机2010年退役的计划以避免过度依赖俄国和减少3500个就业机会

<Florida Today>
Monday, December 15, 2008  

CAPE CANAVERAL -- The Obama administration is taking a sweeping look at NASA that focuses on plans to retire the nation's aging shuttle fleet in 2010.

Five space policy experts -- four of whom held key NASA posts during the Clinton administration -- are gathering data on options to close an anticipated five-year gap in U.S. human spaceflight. They aim to brief the incoming president before his Jan. 20 inauguration.

"They advised us that the shuttle retirement was going to be their No. 1 priority," Brevard County Commissioner Mary Bolin said. "And that was just tremendous to hear because that is a concern for our citizens. That hits us straight in the heart."

"I was very impressed with them," Commissioner Robin Fisher said. "It seems that President-elect Obama has everything in order, and he's moving at a fast pace."

Bolin, Fisher and Lynda Weatherman, president and chief executive of the Economic Development Commission of Florida's Space Coast, met with the Obama's NASA Review Team last week in Washington.

"They welcomed us with open arms and, basically, wanted to be briefed on some of the concerns that we have in Brevard County," Fisher said. "And the loss of jobs is one that is near and dear to my heart. That's something I don't want to see happen."

An estimated 3,500 Kennedy Space Center jobs are expected to be lost during the gap between the shuttle retirement and the first piloted flights of the Ares 1 rocket and the Orion spacecraft in March 2015.

President George W. Bush's plan calls for the United States to rely on Russia to fly American astronauts to and from the International Space Station in the interim. Obama said during his presidential campaign that he wants to minimize the gap and reduce reliance on Russia.

A list of questions submitted to NASA -- excerpts of which were published this month in the trade publication Space News -- shows that President-elect Barack Obama's team is gathering data on a range of options.
The team asked NASA to provide information on the costs involved with:

  Adding one or more shuttle missions beyond the 2010 retirement date.

  Flying the shuttle through 2015.

  Accelerating the development of the Ares 1 rocket and the Orion spacecraft.

But the team also is asking NASA to provide data on other options, such as:

  The costs that could be saved by canceling the Ares 1, Orion and Ares 5 projects.

  The technical challenges engineers face in fielding the Ares 1, such as launch vibrations that could damage the rocket or injure its crew.

  The cost of developing a smaller Orion space capsule that could fly to the station on an upgraded version of an Atlas 5 or Delta 4 rocket.

The feasibility of flying smaller Orion capsules on European Ariane 5 or Japanese H2A rockets.

Former U.S. astronaut Charlie Precourt, vice president of NASA space launch systems for Ares rocket manufacturer ATK, said he isn't surprised that the team is gathering information on such a wide range of options. He calls it "due diligence."

"I think that there are certainly a lot of people that have been asking questions that NASA has revisited and reviewed a number of times, and I think the team wants to revisit and answer these questions to their own satisfaction,"

Precourt said. "I really struggle at trying to make conclusions on where they are going, based on the flavor of the questions, although people like to do that."

Like the Obama teams evaluating 27 other federal agencies, the NASA group is chartered to provide the president-elect with information needed to make policy, budgetary and personnel decisions before the inauguration. The team does not make recommendations.

Precourt thinks a thorough review will lead to a decision to press ahead with the development of the Ares 1 rocket and the Orion spacecraft.

"I think the questions are fairly easily answered," he said. "And those answers will point to the advantages of the Ares-Orion architecture being the right course to continue on."
hpyfy 发表于 2008-12-17 09:42 | 显示全部楼层
就现在美帝下一代天地载人系统的进度,航天风机推迟退役是板上定钉的事了。
 楼主| jingyan66 发表于 2008-12-17 18:51 | 显示全部楼层

Rob Coppinger在博客中写的更多有关“战神”V的信息

More NASA Ares V cargo launch vehicle information


By Rob Coppinger on December 12, 2008 6:36 PM

Find in the extended section of this blog post my notes from reading through NASA's Ares V cargo launch vehicle procurement documentation. The notes are the over matter from the news analysis I wrote this week and the supporting timeline and CaLV point of departure design specification   

Over the four days that it loiters the Earth departure stage (EDS)/Altair Lunar lander stack will degrade to its trans-lunar injection (TLI) altitude of 185km

The total TLI mass combining EDS, Altair and Orion is 66,900kg (147,180lb). For cargo missions the robotic Altair lander will have a mass of 53,600kg, 8,600kg more than the crewed lander

"The Saturn V TLI payload capability was [48,600kg] for the Apollo 17 mission"," NASA states in its pre-Phase study report

NASA examined Saturn, Shuttle and EELV development and testing in planning Ares V's development and testing

CaLV had had baselined the Ares I solid rocket motor (SRM), which saw changes over the Shuttle motor including an additional 1.5 segments, a widened throat, lowered burn rates with a modified polybutadiene acrylonitrile (PBAN) fuel and toxic insulation and liner material removal

The pre-Phase study report reveals that if Ares V had had an additional "third-stage" it could have conducted the Lunar Orbit Insertion burn, not the Altair which could have then been reduced in size. However there was no substantial benefit in reducing Altair so the third-stage was dropped, as well as it being a huge extra cost to develop

NASA states that it has the goals of heritage hardware and commonality. At the moment only the J-2X and Ares V's first-stage is common with Ares I. From what I can see that will be reduced to just the J-2X if Ares V requires an improved first-stage booster and if it does not adopt common avionics with CLV, Altair and Orion

An Ares I lesson learned was to include computatonal fluid dynamics and wind tunnel data as early as possible into the Design Analysis Cycle (DAC)

The EDS' liquid oxygen (LOX) tank has slosh and vortex baffles and needs cryogenic fluid management technologies to preserve propellant on orbit.

The EDS' avionics are in the forward skirt and they control the entire flight. The core's avionics are in its forward skirt

The EDS provides 1.5kW of power to Altair from launch to TLI burn. The EDS' fuel cells are contained in the loiter skirt that is jettisoned just before TLI burn

The composite interstage, between the core and EDS, has a pyrotechnic separartion ring at its forward end near to the loiter skirt

There are retro rockets around the circumference of the core's forward skirt for EDS, core separation

The Ares V SRM exit nozzle is 86cm longer than the Shuttle SRM nozzle and has an exit diameter of 440cm

NASA's 9 July Ares V request for information's timetable shows the first DAC starting next year and preliminary design reviews (PDR) and critical design reviews (CDR) in 2012 and 2013. The pre-Phase study has the PDR occuring later in 2013 and the CDR in 2016

The EDS MPTA is a full-scale flight design stage with a production J-2X
Nighthawk 发表于 2008-12-17 19:02 | 显示全部楼层
我在NASA网站上看到2009年Ares1-X测试的一个模拟视频,是一次亚轨道飞行,用的还是四段的SRB,第五段是质量模拟,上面级也就是简单的质量模拟。飞行完了SRB例行回收,模拟的上面级扔到大西洋里去。
cmj9808 发表于 2008-12-17 21:02 | 显示全部楼层
原帖由 Nighthawk 于 2008-12-17 19:02 发表
我在NASA网站上看到2009年Ares1-X测试的一个模拟视频,是一次亚轨道飞行,用的还是四段的SRB,第五段是质量模拟,上面级也就是简单的质量模拟。飞行完了SRB例行回收,模拟的上面级扔到大西洋里去。

AresI-X只是模拟样机,为的是为AresI的设计提供真实飞行状态的数据,AresI-Y才是验证机
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 楼主| jingyan66 发表于 2008-12-19 10:52 | 显示全部楼层

NASA正在考虑改变哈勃望远镜维修任务要求以保证明年7月Ares 1-X首飞试验

NASA Might Change Hubble Mission Requirement to Keep Ares 1-X on Schedule


         WASHINGTON — NASA officials are weighing whether they need two space shuttle launch pads to support the upcoming Hubble Space Telescope servicing mission or if they can get by with one launch pad, a shift that would help keep the planned July test flight of the Ares 1-X launch vehicle on schedule.
 楼主| jingyan66 发表于 2008-12-19 22:43 | 显示全部楼层

Ares I又不需要主动阻尼系统,改为被动系统解决颤振问题

Ares I Active Damping Unneeded

Dec 18, 2008
By Frank Morring, Jr.  

NASA managers have concluded they don't need an active damping system in the aft skirt of the Ares I first stage to prevent dangerous vibrations from rattling the crew of the Orion crew exploration vehicle on top, and will use a passive system instead.

Steve Cook, the Ares project manager at Marshall Space Flight Center, said Dec. 17 that a follow-up review held 90 days after preliminary design review in September concluded a passive series of weights and springs, coupled with the spring/ring design originally baselined as an isolator between the first and second stages, should keep thrust oscillation in the system at acceptable levels.

The Ares I program has kept thrust oscillation generated by the solid-fuel first stage shortly before it burns out as an open item for a "delta-PDR" early next year, and has been working options to mitigate it. Early calculations suggested the vibrations, when transmitted through the stack to the Orion seats, could endanger crew health or make it difficult for them to read instruments and perform tasks.

Most of those calculations were based on ground-test data from space shuttle solid-fuel boosters, which will form the basis for the Ares I first stage. Since the problem surfaced, the Ares I project has worked with the space shuttle program to instrument shuttle boosters for actual flight data, and that has suggested the early calculations may have overstated the problem.

"We were able to verify that we are definitely getting less thrust oscillation in flight than we see in our ground-test motors," Cook said. "That's good, because where we care about this issue is in flight and not on the ground."

In developing systems to detune the Ares I stack so the thrust oscillation that occurs in all solid-fuel rockets isn't amplified to dangerous levels, Ares I engineers had considered a set of 36 active dampers using electromechanical actuators in the aft skirt to counter vibrations. The passive system eliminates those actuators and still will damp out the vibrations, Cook said.

The spring/ring design for the vibration isolator between the stages was one of three studied, and proved to be the lowest-risk approach, Cook said.

[ 本帖最后由 jingyan66 于 2008-12-21 12:25 编辑 ]
cmj9808 发表于 2008-12-20 13:08 | 显示全部楼层
原帖由 jingyan66 于 2008-12-19 22:43 发表
Ares I Active Damping Unneeded
Dec 18, 2008
By Frank Morring, Jr.  

NASA managers have concluded they don't need an active damping system in the aft skirt of the Ares I first stage to prevent da ...

地面测试时SRB是水平放置的,是否有可能是这个原因造成其thrust oscillation比实际飞行时要大?
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