Northrop Grumman RQ-4 Global Hawk
The Northrop Grumman RQ-4 Global Hawk is an unmanned (UAV) surveillance aircraft. It was initially designed by Ryan Aeronautical (now part of Northrop Grumman), and known as Tier II+ during development. In role and operational design, the Global Hawk is similar to the Lockheed U-2. The RQ-4 provides a broad overview and systematic surveillance using high-resolution synthetic aperture radar (SAR) and long-range electro-optical/infrared (EO/IR) sensors with long loiter times over target areas. It can survey as much as 40,000 square miles (100,000 km2) of terrain a day. The Global Hawk is operated by the United States Air Force and U.S. Navy. It is used as a high-altitude platform covering the spectrum of intelligence collection capability to support forces in worldwide military operations. According to the United States Air Force, the superior surveillance capabilities of the aircraft allow more precise weapons targeting and better protection of friendly forces. Cost overruns led to the original plan to acquire 63 aircraft being cut to 45, and to a 2013 proposal to mothball the 21 Block 30 signal-intelligence variants. Each aircraft was to cost US$35 million in 2005, but this had risen to $222.7 million per aircraft (including development costs) by 2013. The U.S. Navy has developed the Global Hawk into the MQ-4C Triton maritime surveillance platform.
The United States Navy took delivery of two of the Block 10 aircraft to be used to evaluate maritime surveillance capabilities, designated N-1 (BuNo 166509) and N-2 (BuNo 166510). The initial example was tested in a naval configuration at Edwards Air Force Base for several months, later ferrying to NAS Patuxent River on 28 March 2006 to begin the Global Hawk Maritime Demonstration (GHMD) program. Navy squadron VX-20 was tasked with operating the GHMD system. The GHMD aircraft flew in the Rim of the Pacific (RIMPAC) exercise for the first time in July 2006. Although RIMPAC operations were in the vicinity of Hawaii, the aircraft was operated from Edwards, requiring flights of approximately 2,500 mi (4,000 km) each way to the operations area. Four flights were performed, resulting in over 24 hours of persistent maritime surveillance coordinated with Abraham Lincoln and Bonhomme Richard. As a part of the demonstration program, Global Hawk was tasked with maintenance of maritime situational awareness, contact tracking, and imagery support of various exercise operations. In operation, images from Global Hawks were transmitted to NAS Patuxent River for processing before being forwarded to the fleet operations off Hawaii. Northrop Grumman entered a version of the RQ-4B in the US Navy's Broad Area Maritime Surveillance (BAMS) UAV contract competition. On 22 April 2008, the announcement was made that the Northrop Grumman RQ-4N had won the bid, with the Navy awarding a contract worth US$1.16 billion. In September 2010, the RQ-4N was officially designated the MQ-4C. On 11 June 2012, a U.S. Navy RQ-4A Global Hawk crashed near Salisbury, Maryland, during a training flight from Naval Air Station Patuxent River. The Navy MQ-4C differs from the Air Force RQ-4 mainly in its wing. While the Global Hawk remains at high altitude to conduct surveillance, the Triton climbs to 50,000 ft to see a wide area and can drop to 10,000 ft to get further identification of a target. The Triton's wings are specially designed to take the stresses of rapidly decreasing altitude. Though similar in appearance to the Global Hawk's wings, the Triton's internal wing structure is much stronger and has additional features including anti-icing capabilities and impact and lightning strike protection.
In December 2007, two Global Hawks were transferred from the U.S. Air Force to NASA's Dryden Flight Research Center at Edwards Air Force Base. Initial research activities beginning in the second quarter of 2009 supported NASA's high-altitude, long-duration Earth science missions. The two Global Hawks were the first and sixth aircraft built under the original DARPA Advanced Concept Technology Demonstration program, and were made available to NASA when the Air Force had no further need for them. Northrop Grumman is an operational partner with NASA and will use the aircraft to demonstrate new technologies and to develop new markets for the aircraft, including possible civilian uses. According to an article in the March 2010 issue of Scientific American (p. 25-27), the Global Hawk aircraft belonging to NASA were in use for testing purposes as of October 2009, with science missions expected to start in March 2010. Initial science applications included measurements of the ozone layer and cross-Pacific transport of air pollutants and aerosols. The author of the Scientific American piece speculates that the aircraft could be used for Antarctic exploration while based in and operated from Chile. In August–September 2010, one of the two Global Hawks was loaned for NASA's GRIP Mission (Genesis and Rapid Intensification Program). Its long-term on station capabilities and long range made it a suitable aircraft for monitoring the development of Atlantic basin Hurricanes. It was modified to equip weather sensors including Ku-band radar, lightning sensors and dropsondes. It successfully flew into Hurricane Earl off the United States East Coast on 2 September 2010.
+ نوشته شده توسط aryan jamshidi در شنبه شانزدهم اسفند ۱۳۹۳ و ساعت 1:9 |
Mir (Russian: Мир, IPA) space station
Mir (Russian: Мир, IPA: [ˈmʲir]; lit. Peace or World) was a space station that operated in low Earth orbit from 1986 to 2001, owned at first by the Soviet Union and then by Russia. Mir was the first modular space station and was assembled in orbit from 1986 to 1996. It had a greater mass than that of any previous spacecraft. It held the record for the largest artificial satellite orbiting the Earth until that record was surpassed by the International Space Station after Mir's deorbit on 21 March 2001. Mir served as a microgravity research laboratory in which crews conducted experiments in biology, human biology, physics, astronomy, meteorology and spacecraft systems in order to develop technologies required for the permanent occupation of space.
The station was the first consistently inhabited long-term research station in space and was operated by a series of long-duration crews. The Mir programme held the record for the longest uninterrupted human presence in space, at 3,644 days, until 23 October 2010 (when it was surpassed by the ISS), and it currently holds the record for the longest single human spaceflight, of Valeri Polyakov, at 437 days 18 hours. Mir was occupied for a total of twelve and a half years of its fifteen-year lifespan, having the capacity to support a resident crew of three, and larger crews for short-term visits.
Following the success of the Salyut programme, Mir represented the next stage in the Soviet Union's space station programme. The first module of the station, known as the core module or base block, was launched in 1986, and was followed by six further modules, all launched by Proton rockets (with the exception of the docking module). When complete, the station consisted of seven pressurised modules and several unpressurised components. Power was provided by several photovoltaic arrays mounted directly on the modules. The station was maintained at an orbit between 296 km (184 mi) and 421 km (262 mi) altitude and traveled at an average speed of 27,700 km/h (17,200 mph), completing 15.7 orbits per day.
On 5 May 1986, they undocked from Mir for a day-long journey to Salyut 7. They spent 51 days there and gathered 400 kg of scientific material from Salyut 7 for return to Mir. While Soyuz T-15 was at Salyut 7, the unmanned Soyuz TM-1 arrived at the unoccupied Mir and remained for 9 days, testing the new Soyuz TM model. Soyuz T-15 redocked with Mir on 26 June and delivered the experiments and 20 instruments, including a multichannel spectrometer. The EO-1 crew spent their last 20 days on Mir conducting Earth
The station was launched as part of the Soviet Union's manned spaceflight programme effort to maintain a long-term research outpost in space, and, following the collapse of the USSR, was operated by the new Russian Federal Space Agency (RKA). As a result, the vast majority of the station's crew were Soviet or Russian; however, through international collaborations, including the Intercosmos, Euromir and Shuttle-Mir programmes, the station was made accessible to astronauts from North America, several European nations and Japan. The cost of the Mir programme was estimated by former RKA General Director Yuri Koptev in 2001 as $4.2 billion over its lifetime (including development, assembly and orbital operation). The station was serviced by Soyuz spacecraft, Progress spacecraft and U.S. Space Shuttles, and was visited by astronauts and cosmonauts from 12 different nations.
Final days and deorbit
The crew of EO-27, consisting of Viktor Afanasyev and Jean-Pierre Haigneré arrived in Soyuz TM-29 on 22 February 1999 alongside Ivan Bella, who returned to Earth with Padalka in Soyuz TM-28. The crew carried out three EVAs to retrieve experiments and deploy a prototype communications antenna on Sofora. Meanwhile, on 1 June it was announced that the deorbit of the station would be delayed by six months to allow time to seek alternative funding to keep the station operating. The rest of the expedition was spent preparing the station for its deorbit; a special analogue computer was installed and each of the modules, starting with the docking module, was mothballed in turn and sealed off. The crew loaded their results into Soyuz TM-29 and departed Mir on 28 August 1999, ending a run of continuous occupation of the station which had lasted for eight days short of ten years. The station's gyrodynes and main computer were shut down on 7 September, leaving Progress M-42 to control Mir and refine the station's orbital decay rate.
Near the end of its life, there were plans for private interests to purchase Mir, possibly for use as the first orbital television/movie studio. The privately funded Soyuz TM-30 mission by MirCorp, launched on 4 April 2000, carried two crew members, Sergei Zalyotin and Aleksandr Kaleri, to the station for two months to do repair work with the hope of proving that the station could be made safe. This was, however, to be the last manned mission to Mir - while Russia was optimistic about Mir's future, its commitments to the International Space Station project left no funding to support the aging station.
Mir's deorbit was carried out in three stages. The first stage involved waiting for atmospheric drag to reduce the station's orbit to an average of 220 kilometres (140 mi). This began with the docking of Progress M1-5, a modified version of the Progress-M carrying 2.5 times more fuel in place of supplies. The second stage was the transfer of the station into a 165 × 220 km (103 × 137 mi) orbit. This was achieved with two burns of Progress M1-5's control engines at 00:32 UTC and 02:01 UTC on 23 March 2001. After a two-orbit pause, the third and final stage of Mir's deorbit began with the burn of Progress M1-5's control engines and main engine at 05:08 UTC, lasting a little over 22 minutes. Reentry into Earth's atmosphere (100 km/60 mi AMSL) of the 15-year-old space station occurred at 05:44 UTC near Nadi, Fiji. Major destruction of the station began around 05:52 UTC and most of the unburned fragments fell into the South Pacific Ocean around 06:00 UTC. A single piece of the Mir's remains was discovered near Boston, Massachusetts.
+ نوشته شده توسط aryan jamshidi در شنبه بیست و هشتم دی ۱۳۹۲ و ساعت 18:22 |
McDonnell Douglas X-36
The X-36 was built to 28% scale of a possible fighter aircraft, and controlled by a pilot in a ground station virtual cockpit with a view provided by a video camera mounted in the nose of the aircraft.
For control, a canard forward of the wing was used as well as split ailerons and an advanced thrust vectoring nozzle for directional control. The X-36 was unstable in both pitch and yaw axis, so an advanced digital fly-by-wire control system was put in place to stabilize the aircraft.
First flown on May 17, 1997, it made 31 successful research flights. It handled very well, and the program is reported to have met or exceeded all project goals. McDonnell Douglas merged with Boeing in August 1997 while the test program was in progress; the aircraft is sometimes referred to as the Boeing X-36.
The X-36 possessed high maneuverability that would be ideal for use as a fighter. Despite its potential suitability, and highly successful test-program, there have been no reports regarding the X-36's development as of 2010.
+ نوشته شده توسط aryan jamshidi در دوشنبه بیست و یکم مرداد ۱۳۹۲ و ساعت 21:10 |
McDonnell Douglas F-15 Eagle
The McDonnell Douglas (now Boeing) F-15 Eagle is a twin-engine, all-weather tactical fighter designed by McDonnell Douglas to gain and maintain air superiority in aerial combat. It is considered among the most successful modern fighters, with over 100 aerial combat victories with no losses in dogfights. Following reviews of proposals, the United States Air Force selected McDonnell Douglas' design in 1967 to meet the service's need for a dedicated air superiority fighter. The Eagle first flew in July 1972, and entered service in 1976.
Since the 1970s, the Eagle has been exported to Israel, Japan, Saudi Arabia, and other nations. The F-15 was originally envisioned as a pure air superiority aircraft. Its design included a secondary ground-attack capability that was largely unused. The design proved flexible enough that an all-weather strike derivative, the F-15E Strike Eagle, was later developed, and entered service in 1989. The F-15 Eagle is expected to be in service with the U.S. Air Force past 2025.
Following studies in 1964–1965, the U.S. Air Force developed requirements for an air superiority fighter in October 1965. Then on 8 December 1965, the service issued a request for proposals (RFP) for the new fighter. The request called for both air-to-air and air-to-ground capabilities. Eight companies responded with proposals. In the following study phase, four of these companies developed some 500 design concepts. Typical designs featured variable-sweep wings, weighed over 60,000 lb (27,200 kg), included a top speed of Mach 2.7 and a thrust-to-weight ratio of 0.75. The designs were not accepted by the Air Force as they compromised fighter qualities for ground attack qualities. Acceptance of the Energy-Maneuverability (E-M) theory by the Air Force led to a change in requirements for improved maneuverability by the spring 1967. The design mission weight was reduced to 40,000 lb (18,100 kg), top speed reduced to Mach 2.3–2.5 and thrust-to-weight ratio increased to 0.97.
In 1967 U.S. intelligence was surprised to find that the Soviet Union was producing a large fighter aircraft, the MiG-25 'Foxbat'. It was not known in the West at the time that the MiG-25 was designed as a high-speed interceptor, not an air superiority fighter, so its primary asset was speed, not maneuverability. The MiG-25's huge tailplanes and vertical stabilizers (tail fins) hinted at a very maneuverable aircraft, which worried the Air Force that its performance might be better than its U.S. counterparts. In reality, the MiG's large fins and stabilators were necessary to prevent the aircraft from encountering inertia coupling in high-speed, high-altitude flight.
The McDonnell Douglas F-4 Phantom II of the USAF, U.S. Navy and U.S. Marine Corps was the only fighter with enough power, range, and maneuverability to be given the primary task of dealing with the threat of Soviet fighters while flying with visual engagement rules. As a matter of policy, the Phantoms could not engage targets without positive visual identification, so they could not engage targets at long ranges, as designed. Medium-range AIM-7 Sparrow missiles, and to a lesser degree even the AIM-9 Sidewinder, were often unreliable and ineffective at close ranges where it was found that guns were often the only effective weapon. The Phantom did not originally have any guns or cannons, but experience in Vietnam led to the addition of an internally mounted cannon in later versions
There was a clear need for a new fighter that overcame the close-range limitation of the Phantom while retaining long-range air superiority. After rejecting the U.S. Navy VFX program (which led to the F-14 Tomcat) as being unsuited to its needs, the U.S. Air Force issued its own requirements for the F-X (read as Fighter-Unknown, sometimes referred to as Fighter-Experimental), a specification for a relatively lightweight air superiority fighter. The requirements called for single-seat fighter having a maximum take-off weight of 40,000 lb (18,100 kg) for the air-to-air role with a maximum speed of Mach 2.5 and a thrust to weight ratio of nearly 1 at mission weight. Four companies submitted proposals, with the Air Force eliminating General Dynamics and awarding contracts to Fairchild Republic, North American Rockwell, and McDonnell Douglas for the definition phase in December 1968. The companies submitted technical proposals by June 1969. The Air Force announced the selection of McDonnell Douglas on 23 December 1969. The winning design resembled the twin-tailed F-14, but with fixed wings. It would not be significantly lighter or smaller than the F-4 that it would replace.
+ نوشته شده توسط aryan jamshidi در یکشنبه ششم مرداد ۱۳۹۲ و ساعت 22:25 |
Interesting Facts About The International Space Station
350 kilometers up in space orbits the The International Space Station (ISS). It was launched back in 1998 and it’s been the home of astronauts since, making it one the longest uninterrupted human space flight mission to date. It beat the old record of almost 10 years (or 3,634 days) held by the Russian space station Mir. It is definitely an interesting place, and today we’re going to bring 10 interesting facts about the ISS.
The ISS is a joint project of 5 space agencies which include US space agency NASA, Russian Federal Space Agency (RKA), Japan Aerospace Exploration Agency (JAXA), European Space Agency (ESA) and the Canadian space agency (CSA). Over a 100,000 people across the world have collaborated to make the ISS possible.
3rd Brightest Object In The Night Sky
As the ISS passes over head, it sometimes captures sunlight which makes the ISS shine really bright. It’s the 3rd brightest object in the night sky, the only things brighter than the ISS are the Sun and the Moon. It has an apparent magnitude (a measure of how bright things are in the sky) of -5.6, Venus, which is the brightest planet in the night sky, has an apparent magnitude just below -5.
You Can See It From Earth
The ISS is visible to 90% of the population. You can go out and see it! There are plenty of websites and astronomy apps out there that let you know when the ISS is going to make a visible pass in your area, and help you track the current location of the ISS.
The International Space Station gets all its energy from the Sun. Its got over 250,000 solar cells that provide. Laid side-to-side the solar panels span an acre, and they can generate up to 110 killowatts -that’s enough to power 55 homes.
Since the ISS orbits the earth at a speed of 7 km/s, it takes it around 90 minutes to complete one orbit. Astronauts on-board the ISS can see the sunrise 16 times and watch the sunset 17 times.
The Price Tag
It’s estimated that the ISS cost around $100 billion to complete, making the ISS the most expensive single object ever built. The price comes close the entire amount of money spent on the Apollo moon missions.
700,000 Images Downloaded Every Month
700,000 images are downloaded every month by teachers, students and scientists from “The Gateway to Astronaut Photography of Earth”, NASA’s website that hosts all the images taken by the astronauts on the ISS. They issue a weekly top 10 list, you can go ahead and check it out here.
There’s tons of space debris out in orbit, and the ISS has to constantly watch out for that. NASA keeps track of all space debris in the Space Station’s path, and keeps the astronauts alert about possible hazards. If things get tight, the astronauts are prepared to escape in a Soyuz capsule. The hazardous environment in orbit makes the ISS a dangerous place to work for scientists and astronauts.
The International Space Station is based on Mir 2, successor of the Mir Space Station, that was in development back in 1976. Some of the modules used in the ISS were originally designed for the Mir-2. The Zvezda module was originally designed to be the core of Mir-2.
You can Spend A Week In The ISS
Space Adventures is a company that sends civilians into space for a premium price: $20-30 million. That’s correct, if you could afford the insane price tag, you could go to the International Space Station. So far, only 7 civilians have gone to the Space Station. Dennis Tito was the first civilian in space, he spent eight days in orbit on-board the ISS.
If you can’t afford a trip to the ISS, you can at least own a cool scale model of the International Space Station on Amazon
+ نوشته شده توسط aryan jamshidi در پنجشنبه بیستم تیر ۱۳۹۲ و ساعت 21:57 |
Why is the Sky Blue
When you look up to the sky on a clear and sunny day, you see that the sky appears bright blue. You become mesmerized by its beauty and start to ask yourself why the sky is blue. But as the day passes and sunset arrives, you look up and see that the bright blue sky has turned into a combination of reds, oranges, and pinks. Why is that? What makes the sky blue?
Before we can explain the answer to you, there are some basic things you have to know about the colors of light, light waves and the atmosphere in order to understand the reason why the sky is blue.
Colors of Light
Light is actually composed of several colors, and not just white. You can see the different colors by using a prism to split the light. If you don’t have a prism, just look up when you see a rainbow and you can see that light is actually a combination of red, blue, green, yellow, violet, and many more.
All these colors have different frequencies, wavelengths, and energies. In the visible spectrum, violet has the shortest wavelength, meaning it has the highest frequency along with energy. Red, on the other hand, has the longest wavelength, lowest frequency and lowest energy.
Light is a type of energy that travels or radiates in waves. Their energy depends on two things: its frequency and its wavelength. Frequency is the total number of light waves that pass by for every second, while wavelength is the distance amid the crests or tops of the waves. They are indirectly proportional, meaning the longer the wavelength, the lower the frequency and the less energy it possesses.
Why is the Sky Blue
They sky is blue because of Rayleigh scattering. The molecules in the atmosphere scatter the different wavelengths of light coming from the sun. Air molecules like nitrogen and oxygen molecules reflect those with shorter wavelengths like violet, blue or green much better than the longer wavelengths like red, orange or yellow. That is why wherever you look in the sky, you can see scattered blue light overhead.
+ نوشته شده توسط aryan jamshidi در پنجشنبه بیستم تیر ۱۳۹۲ و ساعت 21:9 |
امروز میخوام با یک خاصیت مواد درآیرودینامیک آشناتون کنم
به تایپ کردنش میرزه
تا بحال فکر کردید که چرا وقتی دستتون رو توی آب فرو میبرید دستتون خیس میشه؟
یا چرا بادبادک ها در ارتفاع نزدیک زمین باید بکشیدش تا بالا بره اما وقتی که یه اندازه بالا رفت دیگه نیاز به کشیدن نداره و خود به خود اوج میگیره؟
اینا همش بر میگرده به خاصیت ویژه ای در سیالات به نام ویسکوزیته.
در حقیقت وقتی دستتون رو توی آب فرو میبرید آب به دستتون میچسبه
اگه بخوایم ی معادل فارسی برای ویسکوزیته بگیم بیشتر به چسبندگی شباهت داره
آب با خاصیت ویسکوزیته ای که داره به دستتون میچسبه
این خاصیت در مورد هوا هم وجود داره
هوای نزدیک زمین میشه گفت که به زمین چسبیده و ساکنه پس برای بلا رفتن بادبادک باید بهش نیرو وارد کنید، هرچه که از زمین فاصله میگیریم چسبندگی کمتره و هوا جریان داره و بادبادک در هوای جریان دار ارتفاع اوج میگیره
در بدن انسان هم همینطوره ، هوا به بدن انسان در لایه های نزدیک به پوست میشه گفت که چسبیده و ساکنه
وقتی که انسان سردش میشه دیدید که موهای بدنش سیخ میشه
در حقیقت خدای بزرگمون از ویسکوزیته برای گرم نگه داشتن بدن انسان استفاده میکنه
موهای بدنتون سیخ میشه تا لایه هوایی رو که بدن چسبیده هم بیشتر کنه و به دام بندازه و اطراف بدن این لایه هوای گرم رو نگه داره و هم اینکه انتقال حرارتی رو بین این لایه و هوای عبوری کمتر کنه تا ما دیرتر سردمون بشه
دنیا و هر نفسی که میکشیم پر از شگفتی و نمایش قدرت خداوند بزرگه
کاش بیشتر بدونیم
بدونیم که چی هستیم و کجاییم
+ نوشته شده توسط aryan jamshidi در چهارشنبه دوازدهم تیر ۱۳۹۲ و ساعت 20:26 |
آیا میدانید به همراه یك صندلی اجكت(صندلی نجات خلبان هواپیمای جنگنده) چه چیزهایی وجود دارد؟
4-یك كلت منور.
5- یك قایق بادی مخصوص دراپ در آب.
6-یك قلاب ماهی گیری.
7-یك دستگاه شبیه كباب پز برای طبخ غذا.
8-یك پودر مخصوص كه اگر خلبان در آب دراپ كند با ریختن آن پودر كوسه ها دور می شوند.
9-بسته ی كمك های اولیه.
10-چاقوی معروف و بسیار تیز MC 1 كه حتی قادر به بریدن مفتول فلزی می باشد.
11-آینه برای علامت دادن در روز.
12-یك تشك بادی كه اگر خلبان بالای جنگل دراپ كند.این تشك اطراف بدن او را می پوشاند تا به خلبان آسیبی نرسد.
13-قرص تصفیه آب
معروف ترین شركت سازنده ی صندلی اجكت شركت Martin Backer می باشد.
+ نوشته شده توسط aryan jamshidi در چهارشنبه پنجم تیر ۱۳۹۲ و ساعت 23:22 |
دانستنيهاي جالب درباره كره زمين
خورشيد را 9 سياره احاطه كردهاند كه در بين آنها كره زمين از نظر فاصله با خورشيد، سومين كره است و از چهار سياره داخلي بزرگتر است.
+ نوشته شده توسط aryan jamshidi در چهارشنبه پنجم تیر ۱۳۹۲ و ساعت 22:53 |