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標題: 『每日軍事武器鑑賞』－ X-38 升力體再入式 原型機 [列印本頁]
作者: 克里斯Chris    時間: 07-5-21 17:37
標題: 『每日軍事武器鑑賞』－ X-38 升力體再入式 原型機
X-38
Update: On April 29, 2002, NASA announced the cancellation of the X-38 program due to budget pressures associated with the international space station. The X-38 was two years short of completing its flight test phase.
Engineers at NASA's Dryden Flight Research Center, Edwards, Calif., and the Johnson Space Center, (JSC) Houston, Texas, were flight-testing the X-38, a prototype spacecraft that could have become the first new human spacecraft built in the past two decades that travels to and from orbit. The vehicle was being developed at a fraction of the cost of past human space vehicles. The goal was to take advantage of available equipment, and already developed technology for as much as 80 percent of the spacecraft's design.

Using available technology and off-the-shelf equipment significantly reduces cost. The original estimates to build a capsule-type crew return vehicle (CRV) were more than $2 billion in total development cost. According to NASA project officials, the X-38 concept and four operational vehicles will to be built for approximately one quarter of the original $2 billion cost.

作者: 克里斯Chris    時間: 07-5-21 17:37
Current Status
Full-scale, unpiloted "captive carry" flight tests began at Dryden in July 1997 in which the vehicle remained attached to the NASA B-52 aircraft. Unpiloted free-flight drop tests from the B-52 began in March 1998.




Project Goals
The immediate goal of the innovative X-38 project, was to develop the technology for a prototype emergency CRV, or lifeboat, for the ISS. The project also intended to develop a crew return vehicle design that could be modified for other uses, such as a possible joint U.S. and international human spacecraft that could be launched on the French Ariane 5 booster.

In the early years of the International Space Station, a Russian Soyuz spacecraft was be attached to the station as a CRV. But, as the size of the crew aboard the station increases, a return vehicle that can accommodate up to six passengers would be needed. The X-38 design used a lifting body concept originally developed by the Air Force's X-24A project in the mid-1970's. After the deorbit engine module is jettisoned, the X-38 would glide from orbit unpowered like the Space Shuttle and then use a steerable, parafoil parachute, a technology recently developed by the Army, for its final descent to landing. Its landing gear would consist of skids rather than wheels.

作者: 克里斯Chris    時間: 07-5-21 17:37
Technology


Off-the-shelf technology doesn't mean it is old technology. Many of the technologies used in the X-38 had never before been applied to a human spacecraft.


The X-38 flight computer is commercial equipment that is currently used in aircraft, and the flight software operating system is a commercial system already in use in many aerospace applications. The video equipment on the atmospheric vehicles is existing equipment, some of which has already flown on the Space Shuttle for other NASA experiments. The electromechanical actuators that are used on the X-38 come from a previous joint NASA, Air Force, and Navy research and development project.

An existing special coating developed by NASA was to be used on the X-38 thermal tiles to make them more durable than the tiles used on the Space Shuttle. The X-38's primary navigational equipment, the Inertial Navigation System/Global Positioning System, is a unit already in use on Navy fighters.

作者: 克里斯Chris    時間: 07-5-21 17:38
An, in-house development study of the X-38 concept began at JSC in early 1995. In the summer of 1995, early flight tests were conducted of the parafoil concept by dropping platforms with a parafoil from an aircraft at the Army's Yuma Proving Ground, Yuma, Arizona. In early 1996 a contract was awarded to Scaled Composites, Inc., of Mojave, Calif. to build three full-scale atmospheric test airframes. The first vehicle airframe was delivered to JSC in September 1996, where it was outfitted with avionics, computer systems, and other hardware in preparation for the flight tests at Dryden. A second vehicle was delivered to JSC in December 1996. Team ApproachSome 200 people were working on the project at Johnson, Dryden, and the Langley Research Center in Hampton, Va. This was the first time a prototype vehicle has been built-up in-house at JSC, rather than by a contractor; an approach that has many advantages. By building up the vehicles in-house, engineers had a better understanding of the problems contractors experience when they build vehicles for NASA. JSC's X-38 team will have a detailed set of requirements for the contractor to use to construct the CRVs for the ISS. This type of hands-on work was done by the National Advisory Committee on Aeronautics (NACA), NASA's predecessor, before the space age began. Dryden conducted model flights in 1995. The 1/6 scale-model of the CRV spacecraft using a parafoil parachute system was flown 13 times. The results showed that the vehicle had good flight control characteristics and also demonstrated good slideout characteristics



(文章來自:X檔案)
作者: 克里斯Chris    時間: 07-5-21 17:39
X-38試驗機
維基百科，自由的百科全書

X-38是為國際太空站研製的升力體(lifting body)再入(re-entry)式乘員返回載具的原型機。在2002年因資金問題被終止之前，X-38計劃已經有了一架試驗機。


類型 乘員返回載具


生產公司 Scaled Composites公司 (原型機)
首次飛行 1999年
使用狀態 整個計劃在2002年4月29日被終止
主要用戶 NASA
生產數量 3 + 1（未完成）
作者: 克里斯Chris    時間: 07-5-21 17:39
歷史

能在國際太空站中工作的太空人的人數取決於當時使用的乘員返回載具的載客數。當時國際太空站使用的乘員返回載具是俄羅斯的聯盟號，它只能運載三名太空人。而國際太空站的乘員返回載具必須能在緊急情況下（例如太空人突然生病）運載七名太空人返回地面，因為最多會有七個人在國際太空站內工作。

現在國際太空站的每個乘員返回載具最多能運載三名太空人。NASA在過去的許多年裡設計了許多種具有不同運載能力的乘員返回載具。
作者: 克里斯Chris    時間: 07-5-21 17:40


1999年7月，X-38在德萊登飛行測試中心的一個乾涸的湖床上降落


研發

X-38是由NASA詹森太空中心領導的一系列乘員返回載具項目中的一個。對於X系列試驗機來說很不尋常的是，歐洲太空總署和德國航空太空中心也參與了X-38的研製工作。X-38起初被稱為「X-35」。這個項目的總監為John Muratore，飛行測試工程師為Michael E. Fossum，他後來成為了NASA的太空人。

X-38應用了美國空軍在1960年代中期X-24計劃中研製的升力體佈局，這個是John Muratore的點子。

為了測試新的乘員返回載具，X-38計劃使用了無人的原型機複製品。用於飛行測試的X-38有：

X-38 V-131
X-38 V-132
X-38 V-131R,由X-38 V-131換裝新的蒙皮而成
X-38 V-201,這是由太空梭送入太空的軌道飛行器
在X-38計划進行到一定程度時，人們還提出要建造X-38 V-133和X-38 V-202，但是它們最終沒有被建造

X-38 V-131和V-132與X-24擁有相似的空氣動力外型。當用在乘員返回載具上時，這個外型需要被增大（因為它需要運載七個人），而且它還需要做一些改動，特別是尾部需要增厚。

X-38 V-131R的尺寸為乘員返回載具需要的尺寸的0.8倍大，並且外形與最後定型的乘員返回載具完全相同，而後來的V-133和V-201的尺寸則與定型後的乘員返回載具一模一樣。用作軌道飛行器的X-38 V-201 已有80%被完成，但是它從來沒有飛過。

在測試中，V-131, V-132和V-131R會在45000英尺（13700米）的高空中與B-52母機分離，然後開始以接近音速的速度滑翔，最後打開一個漏斗狀降落傘，速度減到60英里/時（95千米/時）。後來的原型機會藉助一個面積為7500平方英尺（700平方米）的降落傘降落，這是有史以來最大的降落傘。X-38會自動完成這些任務，如果遇到緊急情況，地面上的工作人員會通過遙控來操縱它著陸。

由於資金不足，X-38計劃在2002年4月29日被終止了。
作者: 克里斯Chris    時間: 07-5-21 17:41
設計

在發動機將X-38推出軌道之後，它會用一個可調節方向的翼傘滑翔到地面。升力體飛機極高的速度使降落變得很危險。而翼傘會減低速度，從而使降落變得更安全。X-38的起落架用的是滑橇而不是輪胎。滑橇就像雪橇一樣，使飛機在地面上滑行一段時間後才停住。

X-38的形狀和尺寸都不與太空梭相同。因為乘員返回載具需要能被裝進太空梭的貨艙裡面。但是這並不意味著它會變得很小。X-38有10660千克重，9.1米長。提供動力並運行其他設施的電池能持續提供電力長達九小時。它從國際太空站返回地球只需要二至三小時。

X-38的降落傘應用了美國空軍的技術。這個重量很大的降落傘會將它的性能發揮到極限。X-38首先會從後部放出一個減速傘。這個減速傘會幫助保持飛機平衡，並且會減慢它的速度。在這之後，那個687平方米大的翼傘會被釋放出來。它會分四步被展開，每一步只會耗費45秒。按照一個好的步驟來展開翼傘是非常重要的，這會避免狂風將翼傘撕裂。

X-38的降落是全自動的。各種儀器會將數據送到機上的電腦中，而且電腦還會用空速管和GPS提供的信息來規劃一條安全的返迴路線。設計乘員返回載具的初衷是在緊急情況下將太空人送回地球，所以它必須在沒有人能控制（例如太空人生病或受傷）時自動返回地面。如果需要的話，太空人會將它切換到手動操作模式。

人們為X-38設計了一個先進的對接系統，詹森太空中心接手了這個工作，並且在這基礎上展開了為後來的星座計劃試驗機量身定製的「低碰撞對接系統」計劃。
作者: 克里斯Chris    時間: 07-5-21 17:41
X-38的試飛（檔案資訊）




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