This site uses cookies.
Some of these cookies are essential to the operation of the site,
while others help to improve your experience by providing insights into how the site is being used.
For more information, please see the ProZ.com privacy policy.
This person has a SecurePRO™ card. Because this person is not a ProZ.com Plus subscriber, to view his or her SecurePRO™ card you must be a ProZ.com Business member or Plus subscriber.
Udružen sa
This person is not affiliated with any business or Blue Board record at ProZ.com.
engleski na srpski: Amiga General field: Tehnika/inženjerstvo Detailed field: Računari (uopšteno)
Izvorni tekst - engleski Amiga
The Amiga is a family of personal computers sold by Commodore in the 1980s and 1990s. The first model was launched in 1985 as a high-end home computer and became popular for its graphical, audio and multi-tasking abilities. The Amiga provided a significant upgrade from 8-bit computers, such as the Commodore 64, and the platform quickly grew in popularity among computer enthusiasts. The best selling model, the Amiga 500, was introduced in 1987 and became the leading home computer of the late 1980s and early 1990s in much of Western Europe. In North America success was more modest. The Amiga went on to sell approximately six million units. Second generation Amiga systems (the A1200 and the A4000) were released in 1992. However, poor marketing and failure to repeat the technological advances of the first systems meant that the Amiga quickly lost its market share to competing platforms, such as the fourth generation game consoles, Apple Macintosh and IBM PC compatibles. The name Amiga was chosen because it is the Spanish word for (female) friend, and alphabetically it appears before Apple in lists of computer makers. Originally it was a project with Atari called Lorraine, so therefore the female was used instead of the male and general version Amigo.
Based on the Motorola 68000 family of microprocessors, the machine sports a custom chipset with graphics and sound capabilities that were unprecedented for the price, and a pre-emptive multitasking operating system called AmigaOS. Originally the operating system, partly based on TRIPOS and written in BCPL, was called AmigaDOS and the GUI was called Workbench. Eventually, it was renamed AmigaOS. When renamed to AmigaOS the BCPL parts were rewritten in C language.
Although early Commodore advertisements attempted to cast the computer as an all-purpose business machine, the Amiga was most commercially successful as a home computer, with a wide range of games and creative software. It was also a less expensive alternative to the Apple Macintosh and IBM PC as a general-purpose business or home computer. Initially, the Amiga was developed alongside various PC Compatible Systems by Commodore but later Commodore left the PC market. The platform became particularly popular for gaming and demos. It also found a prominent role in the desktop video, video production, and show control business, leading to affordable video editing systems such as the Video Toaster. The Amiga's native ability to simultaneously play back multiple digital sound samples made it a popular platform for early "tracker" music software. The relatively powerful processor and ability to access several megabytes of memory led to the development of several 3D rendering packages, including LightWave 3D and Aladdin 4D.
Since the demise of Commodore, various groups have marketed successors to the original Amiga line, including Genesi, Eyetech, ACube Systems and A-EON Technology, and AmigaOS has influenced replacements, clones and compatible systems such as MorphOS, AmigaOS 4 and AROS. The demise of Commodore was due to numerous factors such as poor marketing, not being able to recruit sufficient third party developers, not developing the Amiga series to compete with cheaper PC clones with "multimedia" features, and the advent of low-cost color-capable Macintosh models such as the Macintosh LC.
History
"The Amiga was so far ahead of its time that almost nobody—including Commodore's marketing department—could fully articulate what it was all about. Today, it's obvious the Amiga was the first multimedia computer, but in those days it was derided as a game machine because few people grasped the importance of advanced graphics, sound, and video. Nine years later, vendors are still struggling to make systems that work like 1985 Amigas.”
— Byte Magazine, August 1994
Development of the Amiga began in 1982 with Jay Miner, developer of the Atari 800 chip set, as the principal hardware designer of Amiga Corporation. It was initially intended to be a next generation video game machine, but was redesigned as a general purpose computer after the North American video game crash of 1983. A prototype of the full computer was shown to the public for the first time at the Summer Consumer Electronics Show in 1984. In order to bring the design to market Commodore International bought Amiga Corporation and funded development. The first model was released in 1985 as simply "The Amiga from Commodore", later to be retroactively dubbed the Amiga 1000. The following year the Amiga product line was expanded with the introduction of two new models: the Amiga 2000 for high-end graphics and business use, and the Amiga 500 for home use. Commodore later released other Amiga models, both for low-end gaming use and high-end productivity use.
In 1994, Commodore filed for bankruptcy and its assets were purchased by Escom, a German PC manufacturer, who created the subsidiary company Amiga Technologies. They re-released the A1200 and A4000T, and introduced a new 68060 version of the A4000T. However, Escom in turn went bankrupt in 1997. The Amiga brand was then sold to another PC manufacturer, Gateway 2000, which had announced grand plans for it. However, in 2000, Gateway sold the Amiga brand without having released any products. The current owner of the trademark, Amiga, Inc, licensed the rights to sell hardware using the Amiga or AmigaOne brand to computer vendors Commodore USA, Eyetech Group, Ltd. and A-Eon Technology CVBA. Unofficial AmigaOne clones were developed by Italian hardware company, Acube.
Hardware
At its core, the Amiga has a custom chipset consisting of several coprocessors, which handle audio, video and direct memory access independently of the Central Processing Unit (CPU). This architecture freed up the Amiga's processor for other tasks and gave the Amiga a performance edge over its competitors, particularly in terms of video-intensive applications and games.
The general Amiga architecture uses two distinct bus subsystems, namely, the chipset bus and the CPU bus. The chipset bus allows the custom coprocessors and CPU to address "Chip RAM". The CPU bus provides addressing to other subsystems, such as conventional RAM, ROM and the Zorro II or Zorro III expansion subsystems. This architecture enables independent operation of the subsystems; the CPU "Fast" bus can be much faster than the chipset bus. CPU expansion boards may provide additional custom buses. Additionally, "busboards" or "bridgeboards" may provide ISA or PCI buses.
Prevod - srpski Amiga
Amiga je ime familije personalnih računara kompanije Komodor (Commodore) prodavanih tokom osamdesetih i devedesetih godina dvadesetog veka. Prvi model, koji je predstavljen 1985. godine kao kućni kompjuter visoke klase je postao popularan zahvaljujući svojim grafičkim, zvučnim i multitasking sposobnostima. Amiga je predstavljala značajno unapređenje u odnosu na prethodne osmobitne računare, poput Komodora 64, i brzo je stekla popularnost među kompjuterskim entuzijastima. Najprodavaniji model, Amiga 500 se pojavio 1987. godine i vremenom postao vodeći kućni kompjuter druge polovine osamdesetih i prve polovine devedesetih godina u većem delu zapadne Evrope. Na severnoameričkom kontinentu uspeh je bio skromniji. Ukupno je prodano oko šest miliona Amiga računara. Druga generacija Amiga računara (A1200 i A4000) je puštena na tržište 1992. godine. Međutim, loš marketing i neuspeh da se ponove revolucionarna tehnička rešenja koja su krasila prvu generaciju Amiga mašina je rezultovao brzim gubitkom tržišnog udela koga su preuzele konzole za igru četvrte generacije, Epl (Apple) Mekintoš računari i PC kompatibilci. Ime Amiga je odabrano jer je to španska reč za prijateljicu a i u abecednom spisku proizvođača računara se pojavljuje pre Epla. Prvobitno, ceo projekat se zvao Lorena, dok je razvijan u saradnji sa Atarijem, pa je tako žensko ime upotrebljeno umesto opštijeg muškog Amigo.
Bazirana na Motorolinoj 68000 familiji mikroprocesora, Amiga je imala namenski čipset, diskretni grafički i zvučni čip koji nisu imali premca u svojoj cenovnoj kategoriji kao i AmigaOS operativni sistem sa mogućnošću preemptivnog multitaskinga. Operativni sistem, baziran na TRIPOS-u i pisan u BCPL-u se u početku zvao AmigaDOS dok je njegovo grafičko radno okruženje dobilo ime Vorkbenč (Workbench). To ime je naknadno promenjeno u AmigaOS. Prilikom promene imena, delovi operativnog sistema pisani u BCPL-u su ponovo napisani korišćenjem C jezika.
Iako su rane Komodorove reklame predstavljale Amigu kao svestran poslovni računar, ona je najviše uspeha imala kao kućni kompjuter, sa velikom bibliotekom igara i aplikacija namenjenih kreativnoj upotrebi računara poput obrade slike, zvuka i video materijala. Bila je vidno jeftinija alternativa Mekintošu i IBM PC-u kao kućni i poslovni kompjuter opšte namene. Inicijalno, Amiga je bila samo jedna od divizija unutar Komodora, koji je imao i više linija PC računara koje je kasnije napustio. Amiga je postala naročito popularna platforma za pravljenje igara i demoa. Imala je i zapaženu ulogu u segmentima kućnog videa, video produkcije i digitalnog oglašavanja na otvorenom što je dovelo do pojave sistema za obradu videa poput Video Toaster-a. Amigina urođena sposobnost simultanog istovremenog puštanja više digitalnih semplova ju je učinilo poželjnom mašinom za razvoj prvih trekera (audio sekvencera za stvaranje muzike). Relativno moćan procesor i sposobnost linearnog pristupa memoriji od više megabajta su doveli do nastanka više paketa za 2D i 3D rendering poput LIghtWave 3D-a i Aladdin 4D-a
Nakon propasti Komodora, više poslovnih grupacija je promovisalo svoje verzije naslednika klasične Amiga linije, uključujući Genesi, Eyetech, ACube Systems i A-EON Technology dok je AmigaOS bio osnova na kojoj su nastali drugi operativni sistemi poput MorphOS-a , AmigaOS-a 4 i AROS-a. Komodor je bankrotirao usled više faktora od koji su glavni loš marketing, neuspeh u privlačenju većeg broja spoljnih kompanija u svoj ekosistem, kašnjenje u razvoju Amiga sposobnih da se takmiče sa multimedijalnim PC računarima kao i pojava jeftinih Mekintoša u boji poput Macintosh LC-a.
Istorijat
"Amiga je bila toliko ispred svog vremena da gotovo niko - uključujući i marketinško odeljenje Komodora - nije umeo da artikuliše šta je ona u stvari bila.
Danas je jasno uočljivo da je Amiga bila prvi multimedijalni računar, ali je u vreme kada se pojavila bila ismevana kao igračka mašina jer je jako malo ljudi shvatalo bitnost napredne grafike, zvuka i videa. Devet godina kasnije, konkurencija se i dalje muči da tržištu ponudi sistem koji ima mogućnosti kao prvobitna Amiga iz 1985. godine."
- Magazin Bajt (Byte), 1994. godine
Razvoj Amige je počeo 1982. godine, sa Džejem Majnerom (Jay Miner), dizajnerom čipseta za Atari 800 konzolu, kao glavnim projektantom hardvera Amiga Korporacije. Prvobitno, Amiga je razvijana kao sledeća generacija igračke konzole, ali je redizajnirana kao kompjuter opšte namene posle severnoameričkog kraha tržišta video igara 1983. godine. Radni prototip mašine je prikazan javnosti na letnjem CES (Consumer Electronics Show) sajmu 1984. godine. U nastojanju da prototip dovede do serijske proizvodnje, Komodor je kupio Amiga Korporaciju i finansirao dalji razvoj Amiga platforme. Prvi model je izbačen 1985. godine kao "Amiga iz Komodora" da bi kasnije bio preimenovan u Amigu 1000. Naredne godine je linija Amiga računara proširena dodavanjem Amige 2000 za poslovno tržište sa akcentom na vrhunskoj grafici i Amige 500, namenjene kućnim korisnicima. Komodor je tokom godina proširivao gamu Amiga računara i u nižim i u višim segmentima tržišta, odnosno mašinama za igranje i poslovnu primenu.
1994. godine Komodor je bankrotirao a njegovu imovinu je kupio Escom, nemački proizvođač PC računara koji je Amiga diviziju izdvojio u posebnu podružnicu pod imenom Amiga Technologies. Escom je ponovo pokrenuo proizvodnju A1200 i A4000T, ponudivši ovu drugu u staroj verziji sa 68LC040 i novoj sa 68060 procesorom koju Komodor nije nudio. Međutim, 1997. godine je i Escom bankrotirao. Amiga je nakon toga prodata drugom proizvođaču PC računara, firmi Gateway 2000, koja je najavljivala velike planove za nju. Gateway je 2000. godine prodao Amiga brend, ne predstavivši nijedan novi proizvod u vremenu dok ga je posedovao. Trenutni vlasnik zaštitnig znaka Amiga, Amiga Inc. je licencirala prava za proizvodnju i prodaju hardvera pod imenima Amiga ili AmigaOne proizvođačima kompjutera Commodore USA, Eyetech Group, Ltd. i A-Eon Technology CVBA. Italijanska kompanija Acube je razvila nezvanične AmigaOne klonove.
Hardver
U svom srcu, Amiga ima namenski razvijan čipset, koji se sastoji od više koprocesora koji su zaduženi za audio, video i DMA (Direct Memory Access - direktan pristup memoriji) nezavisno od glavnog procesora. Ovakva arhitektura je oslobodila Amigin CPU (Central Processing Unit - glavna procesorska jedinica) za druge zadatke i dala celom sistemu prednost nad konkurencijom, naročito u igrama i aplikacijama koje su se oslanjale na video poput apliakcija za nelinearnu montažu. Amiga arhitektura koristi dve različite magistrale, čipset i procesorsku magistralu. Čipset magistrala omogućava procesoru i koprocesorima pristup čip RAM-u (Random Access Memory - memorija sa slobodnim pristupom). Procesorska magistrala obavlja adresiranje ka drugim podsistemima, poput RAM-a, ROM-a (Read Only Memory - memorija samo za čitanje) i Zorro II i Zorro III slotovima za proširenje. Ovakva organizacija računara omogućava nezavisan rad različitih podsistema; brza procesorska magistrala može biti mnogo brža od magistrale koja opslužuje čipset. Procesorske kartice mogu dodati sopstvene magistrale. Dodatne ekspanzione kartice mogu da implementiraju ISA ili PCI magistrale sa PC mašina.
engleski na srpski: Boeing X-37 General field: Tehnika/inženjerstvo Detailed field: Aeronautika / avijacija / svemir
Izvorni tekst - engleski Boeing X-37
The Boeing X-37, also known as the X-37 Orbital Test Vehicle (OTV), is an American reusable unmanned spacecraft. It is boosted into space by a rocket, then re-enters Earth's atmosphere and lands as a spaceplane. The X-37 is operated by the United States Air Force for orbital spaceflight missions intended to demonstrate reusable space technologies. It is a 120%-scaled derivative of the earlier Boeing X-40.
Origins
In 1999, NASA selected Boeing Integrated Defense Systems to design and develop an orbital vehicle, built by the California branch of Boeing's Phantom Works. Over a four-year period, a total of $192 million was contributed to the project, with NASA contributing $109 million, the U.S. Air Force $16 million, and Boeing $67 million. In late 2002, a new $301-million contract was awarded to Boeing as part of NASA's Space Launch Initiative framework.
The X-37 was transferred from NASA to the Defense Advanced Research Projects Agency (DARPA) on 13 September 2004.Thereafter, the program became a classified project, although it is not known whether DARPA will maintain this status indefinitely. DARPA promoted the X-37 as part of the independent space policy that the United States Department of Defense has pursued since the 1986 Challenger disaster.
The X-37 was originally designed to be carried into orbit in the Space Shuttle's cargo bay, but underwent redesign for launch on a Delta IV or comparable rocket after it was determined that a shuttle flight would be uneconomical. The X-37's aerodynamic design was derived from the Space Shuttle, hence the X-37 has a similar lift-to-drag ratio, and a lower cross range at higher altitudes and Mach numbers compared to DARPA's Hypersonic Technology Vehicle.
As part of its mission goals, the X-37 was designed to rendezvous with friendly satellites to refuel them, or to replace failed solar arrays using a robotic arm. Its payload could also support Space Control (Defensive Counter-Space, Offensive Counter-Space), Force Enhancement and Force Application systems.An early requirement for the spacecraft called for a delta-v of 7,000 mph (3.1 km/s) to change its orbit.
Glide testing
The vehicle that was used as an atmospheric drop test glider had no propulsion system. Instead of an operational vehicle's payload bay doors, it had an enclosed and reinforced upper fuselage structure to allow it to be mated with a mothership. In September 2004, DARPA announced that for its initial atmospheric drop tests the X-37 would be launched from the Scaled Composites White Knight, a high-altitude research aircraft.
On 21 June 2005, the X-37A completed a captive-carry flight underneath the White Knight from Mojave Spaceport in Mojave, California.Through the second half of 2005, the X-37A underwent structural upgrades, including the reinforcement of its nose wheel supports. Further captive-carry flight tests and the first drop test were initially expected to occur in mid-February 2006. The X-37's public debut was scheduled for its first free flight on 10 March 2006, but was canceled due to an Arctic storm.The next flight attempt, on 15 March 2006, was canceled due to high winds.
On 24 March 2006, the X-37 flew again, but a datalink failure prevented a free flight, and the vehicle returned to the ground still attached to its White Knight carrier aircraft. On 7 April 2006, the X-37 made its first free glide flight. During landing, the vehicle overran the runway and sustained minor damage.Following the vehicle's extended downtime for repairs, the program moved from Mojave to Air Force Plant 42 (KPMD) in Palmdale, California for the remainder of the flight test program. White Knight continued to be based at Mojave, though it was ferried to Plant 42 when test flights were scheduled. Five additional flights were performed,two of which resulted in X-37 releases with successful landings. These two free flights occurred on 18 August 2006 and 26 September 2006
On 17 November 2006, the U.S. Air Force announced that it would develop its own variant from NASA's X-37A. The Air Force version was designated the X-37B Orbital Test Vehicle (OTV). The OTV program was built on earlier industry and government efforts by DARPA, NASA and the Air Force, and was led by the U.S. Air Force Rapid Capabilities Office, in partnership with NASA and the Air Force Research Laboratory. Boeing was the prime contractor for the OTV program. The X-37B was designed to remain in orbit for up to 270 days at a time. The Secretary of the Air Force stated that the OTV program would focus on "risk reduction, experimentation, and operational concept development for reusable space vehicle technologies, in support of long-term developmental space objectives."
The X-37B was originally scheduled for launch in the payload bay of the Space Shuttle, but following the 2003 Columbia disaster, it was transferred to a Delta II 7920. The X-37B was subsequently transferred to a shrouded configuration on the Atlas V rocket, following concerns over the unshrouded spacecraft's aerodynamic properties during launch.Following their missions, X-37B spacecraft land on a runway at Vandenberg Air Force Base, California, with Edwards Air Force Base as an alternate site.[23] In 2010, manufacturing work began on the second X-37B, OTV-2,which conducted its maiden launch in March 2011.
Design
At the time of its maiden launch, the X-37 was the smallest and lightest orbital space plane yet flown. Both the North American X-15 and SpaceShipOne were suborbital. Of the space planes shown, only the X-37 and Buran conducted unmanned spaceflights.
The X-37 Orbital Test Vehicle is a reusable robotic space plane. It is a 120%-scale derivative of the Boeing X-40, measuring over 29 feet (8.8 m) in length, and features two angled tail fins. The X-37 launches atop an Atlas V version 501 rocket with a Centaur second stage. The X-37 is designed to operate in a speed range of up to Mach 25 on its reentry.
Among the technologies demonstrated in the X-37 include an improved thermal protection system, enhanced avionics, an autonomous guidance system and an advanced airframe. The space plane’s thermal protection system is built upon previous generations of atmospheric reentry spacecraft, incorporating silica ceramic tiles. The X-37's avionics suite was used by Boeing to develop its CST-100 manned spacecraft. According to NASA, the development of the X-37 will "aid in the design and development of NASA's Orbital Space Plane, designed to provide a crew rescue and crew transport capability to and from the International Space Station".
The X-37 is independently powered by one Aerojet AR2-3 engine using storable propellants, providing thrust of 6,600 pounds-force (29.341 kN).The human-rated AR2-3 engine had been used on the dual-power NF-104A astronaut training vehicle, and was given a new flight certification for use on the X-37 with hydrogen peroxide/JP-8 propellants.
The X-37 lands automatically upon returning from orbit, and is the second reusable spacecraft to have such a capability, after the Soviet Buran shuttle. The X-37 is the smallest and lightest orbital space plane flown to date; with a launch mass of around 11,000 pounds (5,000 kg), it is approximately a quarter the size of the Space Shuttle orbiter.
Operational history
OTV-1
OTV-1, the first X-37B, launched on its first mission – USA-212 – on an Atlas V rocket from Cape Canaveral Air Force Station, Florida, on 22 April 2010 at 23:58 GMT. The spacecraft was placed into low Earth orbit for testing. While the U.S. Air Force revealed few orbital details of the mission, amateur astronomers claimed to have identified the spacecraft in orbit and shared their findings. A worldwide network of amateur astronomers reported that, on 22 May 2010, the spacecraft was in an inclination of 39.99 degrees, circling the Earth once every 90 minutes on an orbit 249 by 262 miles (401 by 422 km). OTV-1 reputedly passed over the same given spot on Earth every four days, and operated at an altitude of 255 miles (410 km), which is typical for military surveillance satellites. Such an orbit is also common among civilian LEO satellites, and the space plane’s altitude was the same as that of the ISS and most other manned spacecraft.
The U.S. Air Force announced on 30 November 2010 that OTV-1 would return for a landing during the 3–6 December timeframe. As scheduled, OTV-1 de-orbited, reentered Earth's atmosphere, and landed successfully at Vandenberg AFB on 3 December 2010, at 1:16 PST (09:16 UTC), conducting America's first autonomous orbital landing onto a runway; the first spacecraft to perform such a feat was the Soviet Buran shuttle in 1988. In all, OTV-1 spent 224 days in space. OTV-1 suffered a tire blowout during landing and sustained minor damage to its underside.
OTV-2
OTV-2, the second X-37B, launched on its inaugural mission, designated USA-226, aboard an Atlas V rocket from Cape Canaveral on 5 March 2011. The mission was classified and described by the U.S. military as an effort to test new space technologies. On 29 November 2011, the U.S. Air Force announced that it would extend the mission of USA-226 beyond the 270-day baseline design duration. In April 2012, General William L. Shelton of the Air Force Space Command declared the ongoing mission a "spectacular success".
On 30 May 2012, the Air Force stated that OTV-2 would complete its mission and land at Vandenberg AFB in June 2012. The spacecraft landed autonomously on 16 June 2012, having spent 469 days in space.
OTV-3
OTV-3, the second mission for the first X-37B and the third X-37B mission overall, was originally scheduled to launch on 25 October 2012, but was postponed because of an engine issue with the Atlas V launch vehicle. The X-37B was successfully launched from Cape Canaveral on 11 December 2012. The classified mission is designated USA-240 and is expected to last several months.
Controversies
In 2010, Tom Burghardt wrote for Space Daily that the X-37B could be used as a spy satellite or to deliver weapons from space. The Pentagon has denied claims that the X-37B's mission supports the development of space-based weapons. In January 2012, allegations were made that the X-37B was being used to spy on China's Tiangong-1 space station module. Former U.S. Air Force orbital analyst Brian Weeden later refuted this claim, emphasizing that the different orbits of the two spacecraft precluded any practical surveillance fly-bys.
Variants
X-37A
The X-37A was the initial NASA version of the spacecraft; the X-37A Approach and Landing Test Vehicle (ALTV) was used in drop glide tests in 2005 and 2006.
X-37B
The X-37B is a modified version of the NASA X-37A, intended for the U.S. Air Force. It conducted orbital test missions in 2010, 2011 and 2012.
X-37C
In 2011, Boeing announced plans for a scaled-up variant of the X-37B, referring to the spacecraft as the X-37C. The X-37C would be between 165% and 180% larger than the X-37B, allowing it to transport up to six astronauts inside a pressurized compartment housed in the cargo bay. Its proposed launch vehicle is the Atlas V Evolved Expendable Launch Vehicle. The X-37C may compete with Boeing's CST-100 commercial space capsule.
Specifications
X-37B
General characteristics
Crew: None
Length: 29 ft 3 in (8.9 m)
Wingspan: 14 ft 11 in (4.5 m)
Height: 9 ft 6 in (2.9 m)
Loaded weight: 11,000 lb (4,990 kg)
Powerplant: 1 × Aerojet AR2-3 rocket engine (hydrazine), 6,600 lbf (29.3 kN)
Power: Gallium arsenide solar cells with lithium-ion batteries
Payload bay: 7 ft × 4 ft (2.1 m × 1.2 m)
Performance
Orbital speed: 28,044 km/h (17,426 mph)
Orbit: Low Earth orbit
Orbital time: 270 days (design)
Prevod - srpski Boing X-37
Boing X-37, poznat i pod imenom X-37 Orbitalno test vozilo (OTV) je američka višekratna bespilotna letelica. Lansira se u svemir pomoću rakete, a vraća se u zemljinu atmosferu i sleće kao kosmički avion. X-37 se koristi od strane Vojnog vazduhoplovstva Sjedinjenih Američkih Država za orbitalne kosmičke misije u cilju demonstriranja tehnologija za višekratne kosmičke letelice. On je 120% uvećana verzija Boingove prethodne letelice X-40.
Poreklo
1999. godine NASA je izabrala Boingovu podružnicu Boing integrisani odbrambeni sistemi da dizajnira i razvije orbitalnu letelicu; kalifornijska filijala kompanije, Boing fantom vorks (Phantom Works) je bila zadužena za izgradnju X-37. Tokom četvorogodišnjeg perioda, u projekat je ukupno uloženo 192 miliona dolara, od čega je NASA uložila 109 miliona, vazduhoplovstvo (USAF) 16 miliona i Boing 67 miliona američkih dolara. Krajem 2002. godine, kao deo okvirne strategije NASA Inicijativa za kosmička lansiranja (Space Launch Initiative) Boing je dobio novi ugovor, vredan 301 milion dolara.
Trinaestog septembra 2004. godine NASA je ustupila X-37 projekat Odbrambenoj agenciji za istraživanje naprednih projekata (DARPA). Nakon tog datuma, ceo projekat postaje klasifikovan kao tajni, ali nije poznato da li DARPA namerava da trajno zadrži takav status projekta. DARPA je promovisala X-37 kao deo politike nezavisnog pristupa kosmosu Ministarstva odbrane koja se sprovodi od nesreće šatla Čelendžer (Challenger) 1986. godine.
X-37 je po prvobitnom dizajnu trebao da do kosmosa dospe u tovarnom prostoru Spejs šatla, ali je tokom razvoja prilagođen lansiranju pomoću rakete sa nosivošću u klasi rakete Delta IV nakon što je ustanovljeno da let šatlom nema ekonomskog opravdanja. Aerodinamički dizajn X-37 je izveden iz šatla, pa tako X-37 ima sličan odnos sile podizanja i čeonog otpora vazduha ali i niži dolet upravan na pravac leta na većim visinama i manju brzinu u odnosu na stariju DARPA eksperimentalnu hipersoničnu letelicu HTV (Hypersonic Technology Vehicle).
Kao jedan od osnovnih postulata, X-37 je dizajniran za susrete sa prijateljskim satelitima kako bi ih snabdeo gorivom ili zamenio oštećene solarne panele pomoću svoje robotske ruke. Njegov tovarni prostor može takođe da prihvati module namenjene misijama za uspostavljanje vojnog prisustva u kosmosu, njegovog širenja kao i kontrolu kosmičkog prostora (ofanzivni i defanzivni protivkosmički sistemi za dejstvo nad kosmičkim ciljevima). Jedan od zahteva u ranom stadijumu razvoja letelice je podrazumevao delta-v (brzina koja je potrebna da bi se izvršio orbitalni manevar radi promene trajektorije letelice) od 7000 milja na čas (11600 km/č, 3,1km/s).
Testiranje jedrenja
Primerak letelice koji je korišten u testovima jedrenja nije imao ugrađene motore. Umesto vrata tovarnog prostora koja se kod operativne letelice nalaze na gornjem delu trupa, gornja sekcija trupa je bila zatvorena i ojačana, kako bi mogla da bude spojena sa avionom nosačem. U septembru 2004. godine, DARPA je objavila da će prilikom prvog atmosferskog testa otpuštanja X-37 i jedrenja iz aviona, kao avion nosač biti korišten Beli Vitez (White Knight), eksperimentalni avion namenjen aerodinamičkim istraživanjima na velikim visinama kompanije Skejld Kompozits (Scaled Composites).
21. juna 2005. godine, X-37A je izveo let učvršćen za Belog Viteza, koji je poleteo sa aerodroma Mohave koji se nalazi u mestu Mohave, u Kaliforniji. Tokom druge polovine 2005. godine, X-37A je doživeo niz strukturnih unapređenja, uključujući ojačanje postolja prednjeg točka. Dalji testovi u ovoj konfiguraciji letelice su prvobitno bili planirani za sredinu februara 2006. godine. Prvo javno prikazivanje X-37 je trebalo da se dogodi 10. marta 2006. godine, ali je odloženo zbog oluje. Sledeći pokušaj, 15. marta 2006 godine je takođe otpao, usled jakih vetrova nad aerodromom.
24. marta 2006 godine X-37 je ponovo poleteo ali je kvar u sistemu prenosa informacija onemogućio slobodan let, tako da se letelica sputila na aerodrom dok je i dalje bila prikačena za Belog Viteza. 7. aprila 2006. godine X-37 je izveo svoj prvi slobodan let u modu jedrenja. Tokom sletanja, letelica je premašila pistu i pretrpela manja oštećenja. Nakon produženog vremenskog perioda za opravku letelice, ceo program je premešten iz Mohave u Fabriku 42 Vojnog vazduhoplovstva u Palmdejlu u Kaliforniji do kraja ciklusa probnih letova. Beli Vitez je i dalje bio stacioniran na aerodromu Mohave, ali je prevožen do Fabrike 42 kadgod su letni testovi bili zakazani. Pet naknadnih testova je bilo izvedeno, od kojih je u dva slučaja X-37 uspešno otpušten sa Belog Viteza i sleteo na aerodrom. Ova dva uspešna leta su se odigrala 18. avgusta i 26. septembra 2006. godne.
17. novembra 2006. godine Vojno vazduhoplovstvo je objavilo da planira da razvije sopstvenu verziju NASA X-37 letelice. Ta nova verzija je dobila naziv X-37B Orbitalno test vozilo (OTV). OTV program je nastao na temeljima ranijih projekata države i privrede od strane DARPA-e, NASA-e i Vojnog vazduhoplovstva. Projektom rukovodi Odeljenje za brza dejstva Vojnog vazduhoplovstva(USAF Rapid Capabilities Office) zajedno sa NASA-om i Istraživačkom laboratorijom Vojnog vazduhoplovstva (Air Force Research Laboratory). Boing je bio glavni izvođač radova u programu OTV. X-37 je dizajniran tako da može da neprekidno provede do 270 dana u orbiti Zemlje. Sekretar Vojnog vazduhoplovstva pri Ministarstvu odbrane je izjavio da će se program OTV fokusirati na "smanjenje rizika, eksperimentisanje i operativni razvoj koncepta višekratne kosmičke letelice u sklopu podrške dugoročnim razvojnim kosmičkim ciljevima"
X-37B letelica je originalno trebalo da bude lansirana pomoću Spejs Šatla, ali je nakon katastrofe šatla Čelendžer 2003 godine, preusmerena na raketu Delta II 7920. X-37B je naknadno premeštena na verziju rakete Atlas V sa zaštitnom oplatom za korisni teret usled strahovanja vezanih za aerodinamičke osobine nezaštićene letelice na vrhu rakete tokom lansiranja. Nakon završetka orbitalnih misija, X-37B sleću na pistu Vazduhoplovne baze Vandenberg u Kaliforniji, dok je Vazduhoplovna baza Edvards alternativna lokacija za sletanje. 2010. godine je počeo rad na drugom primerku X-37B, pod kodnim imenom OTV-2 koji je svoje prvo lansiranje obavio u martu 2011. godine.
Dizajn
U vreme svog prvog lansiranja, X-37 je bio najmanji i najlakši orbitalni kosmički avion koji je ikada leteo. Njegovi prethodnici, Nort Ameriken (North American) X-15 i Svemirski Brod Jedan (SpaceShipOne) su bili suborbitalni. Od prikazanih kosmičkih brodova, samo su X-37 i Buran obavili letove bez ljudske posade.
X-37 OTV je višekratni robotski kosmički avion. On je 120% uvećana verzija Boingove X-40 letelice, dugačka 29 stopa (8,8 metara) i poseduje dva repna peraja postavljena pod uglom u odnosu na telo letelice. X-37 se lansira u orbitu pomoću rakete Atlas V 501, sa drugim stepenom tipa Kentaur. X-37 je dizajniran da izdrži brzine do 25 maha prilikom povratka u atmosferu.
Neke od tehnologija koje su demonstrirane na letelici X-37 su unapređeni termoizolacioni sistem, unapređena avionika, autonomni sistem navigacije i unapređeno telo letelice. Sistem termalne izolacije kosmičkog aviona je rađen na osnovama sličnih sistema na letelicama starijih generacija koji su u tu svrhu koristili silicijumsko - keramičke pločice. Avionika sa X-37 je korištena prilikom razvoja Boingove svemirske kapsule sa ljudskom posadom CST-100. Po izjavama NASA-e, razvoj X-37 će "pomoći u dizajnu i razvoju NASA Orbitalnog kosmičkog aviona (Orbital Space Plane) namenjenog transportu ka i spasavanju posade sa Međunarodne svemirske stanice (ISS)"
X-37 ima nezavisni pogon koji s sastoji od jednog Aerodžet (Aerojet) AR2-3 motora na tečno gorivo sa 6600 funti potiska (29341 kilonjutna). Motor AR2-3 koji je sertifikovan za upotrebu na letelicama sa ljudskom posadom i koji je prethodno bio korišten na modifikovanom dvomotornom avionu NF-104A za obuku astronauta, je dobio novi sertifikat za upotrebu na X-37 u kombinaciji sa vodonik peroksid/JP-8 mešavinom goriva.
X-37 sleće automatski nakon povratka sa orbite, i predstavlja drugu letelicu sa tom mogućnošću, nakon sovjetskog šatla Buran. X-37 je najmanji i najlakši orbitalni kosmički avion koji je ikada leteo do sada; sa startnom masom od oko 11000 funti (5000 kilograma), on je oko četiri puta manji od Spejs šatla.
Istorijat operacija
OTV-1
OTV-1, prvi X-37B, je lansiran na svoju prvu misiju kodnog imena USA-212 na vrhu rakete Atlas V sa kosmodroma Kejp Kanaveral (Cape Canaveral) na Floridi 22.aprila 2010.godine, u 23:58 po londonskom vremenu. Letelica je postavljena u nisku orbitu radi testiranja njenih sistema. Uprkos tome što je Vojno vazduhoplovstvo obelodanilo malo informacija o samoj misiji, astronomi amateri koji tvrde da su identifikovali letelicu na orbiti su predstavili svoje nalaze javnosti. Svetska mreža astronoma amatera je izvestila da je 22.maja 2010.godine letelica imala nagib orbite od 39,99 stepeni u odnosu na ekvator, da jednu punu orbitu oko Zemlje ostvari za 90 minuta i da su perigej i apogej njene orbite 249 odnosno 262 milje (401 sa 422 kilometra). OTV-1 je po generalnoj pretpostavci prelazio iznad iste tačke na Zemlji svaka četiri dana i radio na visini od 255 milja (410 kilometara) što je tipična visina za vojne špijunske satelite Takva orbita je takođe uobičajena i za civilne satelite namenjene niskoj orbiti a visina orbite letelice je ista ona koju ima ISS (Međunarodna kosmička stanica) i većina letelica sa ljudskom posadom.
USAF je izjavilo 30.novembra 2010.godine da će se OTV-1 prizemljiti u periodu između 3. i 6. decembra 2010.godine. Po rasporedu, OTV-1 je izveo deorbitalni manevar, ušao u atmosferu i uspešno sleteo na pistu baze Vandenberg 3.decembra 2010.godine, u 01:16 časova po pacifičkom vremenu (09:16 po griničkom), kompletirajući na taj način prvo američko autonomno sletanje na pistu sa orbite; prva letelica u istoriji koja je izvršila taj manevar je bio sovjetski šatl Buran 1988.godine. OTV-1 je ukupno proveo 224 dana na orbiti. OTV-1 je pretrpeo manje oštećenje donjeg dela trupa prilikom sletanja kada je pukla jedna od guma na stajnom trapu.
OTV-2
OTV-2, drugi X-37B je lansiran na lansiran na svoju inaguracionu misiju kodnog imena USA-226 pomoću rakete Atlas V sa Kejp Kanaverala 5.marta 2011.godine. Misija je bila klasifikovana kao tajna i opisana od strane vojske kao napor da se testiraju nove kosmičke tehnologije. 29.novembra 2011.godine, USAF je izjavilo da će misiju USA-226 produžiti nakon što istekne prvobitno vreme trajanja misije od 270 dana. U aprilu 2012.godine, general Vilijem Šelton (William L. Shelton) iz Kosmičke komande USAF (Air Force Space Command) je izjavio da je misija koja je u toku "spektakularan uspeh".
30.maja 2012.godine, USAF je izjavilo da će OTV-2 kompletirati svoju misiju i sleteti u bazu Vandenberg u junu te godine. Letelica je automatski sletela 16.juna 2012.godine, nakon 469 dana provedena na orbiti.
OTV-3
OTV-3, druga misija prve X-37B letelice, i ukupno treća misija X-37B programa je prvobitno bila planirana da otpočne 25.oktobra 2012. godine, ali je odložena nakon kvara na jednom od motora rakete nosača Atlas V. X-37B je uspešno lansirana sa Kejp Kanaverala 11.decembra 2012.godine. Tajna misija je dobila oznaku USA-240 i očekuje se da će trajati više meseci.
Kontroverze
2010. godine, Tom Burgard (Tom Burghardt) je objavio članak za Spejs dejli (Spce Daily) časopis u kome tvrdi da X-37B može biti korišten kao špijunski satelit ili kao avion nosač orbitalnog oružja. Pentagon je demantovao navode da misija letelice X-37B podržava razvoj kosmičkog oružja. U januaru 2012.godine, iznete su tvrdnje da se X-37B koristi kako bi špijunirao kinesku kosmičku stanicu Tiangong-1. Bivši USAF analitičar za orbitalne sisteme Brajan Viden (Brian Weeden) je kasnije osporio ovu tvrdnju, naglašavajući da različite orbite letelice i kosmičke stanice onemogućavaju bilo kakvo praktično nadgledanje preletom.
Varijante
X-37A
X-37A je bila prva, NASA verzija letelice; X-37A ALTV letelica namenjena testiranju prilaza i sletanja na pistu (Approach and Landing Test Vehicle (ALTV)) je bila korištena u testovima odvajanja od aviona naosača i jedrenja tokom 2005. i 2006.godine.
X-37B
X-37B je modifikovana verzija NASA X-37A letelice, namenjena USAF-u. Ona je obavila orbitalne eksperimentalne misije 2010.,2011.i 2012.godine.
X-37C
2011.godine Boing je obelodanio planove za uvećanu varijantu X-37B, pod imenom X37C. X37C će biti između 165% i 180% veći od X-37B i omogućiće trnasport do 6 astronauta u hermetički zatvorenom odeljku pod pritiskom koji će se nalaziti u tovarnom prostoru letelice. Predložena raketa nosač za X-37C je Atlas V EELV(Evolved Expendable Launch Vehicle - Unapređena raketa za jednokratnu upotrebu). X-37C će se možda takmičiti sa Boingovom CST-100 kapsulom namenjenom za civilno tržište.
Specifikacije
X-37B
Osnovne karakteristike
Posada: Nije predviđena
Dužina: 29 stopa, 3 inča (8,9 metara)
Raspon krila: 14 stopa 11 inča (4,5 metara)
Visina: 9 stopa 6 inča (2,9 metara)
Masa pune letelice: 11000 funti (4990 kilograma)
Pogonska grupa: 1* Aerodžet AR2-3 motor sa pogonom na hidrazin, potiska od 6600 funti (29,3 kilonjutna)
Izvor električne energije: Galijum-arsenidne solarne ćelije sa litijum-jonskim baterijama.
Tovarni prostor: 7 stopa * 4 stope (2,1 metara * 1,2 metra)
Performanse
Orbitalna brzina: 28044 km/č (17426 milja na čas)
Orbita: niska orbita (LEO - Low Earth Orbit)
Vreme boravka na orbiti: 270 dana (po dizajnu)
More
Less
Iskustvo
Godine iskustva: 18. Registrovan/a na ProZ.com: Jan 2014.
Computer Science, Information technology, hardware and software manuals, product specifications and brochures
Gaming industry, announcements, tournaments, analysis, MMO descriptions, e-sports, game localization
Aviation and space technology,
Political, media and marketing analysis, copy writing slogans
General and military history books
Key skills:
Extensive computer training, including knowledge of multiple operating systems and business software packages.
Skilled at learning new concepts quickly, working well under pressure, and communicating ideas clearly and effectively.
Skilled in implementing standardized policies and procedures.
Terms & Conditions:
Prices are negotiable, the final price depends on the length, complexity, specialization and editability of the source text. Prices, project orders, requirements and procedures must be agreed upon before the start of the project. One free sample translation up to 300 words per client is available upon client's request.
Ovaj korisnik je zaradio KudoZ poene pomažući drugim prevodiocima u vezi sa terminima na PRO nivou. Kliknite na ukupan broj poena da biste videli ponuđene prevode termina.
Stručnost