X-ray Telescope

X-RAY TELESCOPE:

     X-rays are absorbed by Earth's atmosphere, so one has to climb above the atmosphere to see them. National Aeronautics Space Administration (NASA's) Uhuru 1970 and the United Kingdom's Ariel V 1974 were spin-stabilized satellites that discovered around 400 bright X-ray sources. Astronomers realized that X-rays provide vital clues to the death throws of stars, specifically supernova explosions and the final transitions to white dwarf, neutron star and black hole states. X-rays are a vital component of the radiation coming from energetic events such as solar flares.

FIRST X-RAY TELESCOPE:

     Two technical advances helped the development of space telescopes. One was the construction of advanced confocal mirror systems and the other was the development of two dimensional X-ray imaging gas scintillation proportional counters. Using these, these United States launched the first orbiting satellite containing a fully imaging X-ray Telescope, the High Energy Astrophysical Observatory-2 (HEAO-2), in November 1978.

HIGH ENERGY ASTROPHYSICAL OBSERVATORY-2

     HEAO-2 was renamed Einstein when it was in orbit and operating correctly. Einstein discovered that nearly all astronomical bodies emit X-rays. Also the angular resolution (few seconds of arc) and the sensitivity was such that accurate maps could be made of objects such as Cygnus loop supernova remnant. The Einstein instruments were a thousand times more sensitive than those on Uhuru.

OTHER X-RAY TELESCOPES:

 

     Einstein remained operational until April 1981. Other space telescopes have followed, such as Exosat, Rosat, Chandra and XXM Newton, and all have continued the quest for ever higher detail and sensitivity. In addition to new sources being discovered, it has been found that many X-rays are being emitted as material falls into the black holes at the center of active galactic nuclei.

QUOTES:

" For NASA, space is still a high priority....If we don't succeed we run the risk of failure"

                                                                                               -Dan Quayle, U.S vice-president.

Credit: The Internet Age | 1001 Invention that changed the world |  

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Geostationary Communication Satellite 1964

The Hughes Aircraft company facilitates phone calls between continents.

Geostationary Communication Satellites:

      In 1945, in an article entitled Extra-Terrestrial Relays British novelist Arthur C.Clarke described a way to bounce information off orbiting satellites so one side of the earth could communicate with other almost instantly. Although the idea had been put forward previously by Russian Scientist Konstantin Tsiolkovsky, it was Clarke's detailed description that caught the attention of Harold Rosen of Hughes Aircraft Corporation. In 1961 the project, called The Synchronous Communications Satellite Program was given funding to make it happen.

Synchronous Communications Satellite Program:

      A mere seventeen months later the satellite Syncom I was launched, but it stopped sending signals before it reached the orbit. Syncom II, which followed in 1963, achieved a geosynchronous orbit ( it traveled at an inclined angle, so was not stationary above one spot) but nevertheless proved the concept with a two-way satellite call between President Kennedy in the United States and Prime Minister Abubakar Balewa in Nigeria. Syncom III finally achieved a true geostationary orbit in 1964 and transmitted live television coverage of the Tokyo Olympic Games to North America and Europe.

Geostationary Orbit:

      Today, due to the proliferation of satellite-building worldwide, establishing a satellite in geostationary orbit is not simply a matter of launching spacecrafts as required. Satellites traveling at the same speed as Earth in geostationary orbit must all occupy a single ring 35,800 km above the equator. The satellite have to be spaced apart, so the number in geostationary orbit is naturally restricted. Those countries wishing to maintain satellites in the skies above their longitude, as well as those wanting to control airspace above the equator, are governed by International Allocation Mechanism.

Quotes:

 " In the long run ... the most daring prophecies seem laughably conservative"

                                                                                       -Arthur C.Clarke, novelist and writer.

Text Credit : Inventions that changed the World

Tags: Satellite Radio Communication | Scramjet | Space Probe | Geostationary Communication Satellite

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Scramjet 2002

The University of Queensland and Qinetiq develop hyper-sonic travel:

Travel Faster:

     In the twenty first century, speed seems to be of paramount importance. As well as improving the simple but inefficient turbine based engine systems that drive rockets and planes, scientists have developed Supersonic Combustion Ramjet engines (Scramjet) to allow much faster travel.

Scramjet Developmemnt:

     Scramjets improve on ordinary engines by eliminating the need to carry fuel oxidant. Instead of using oxidant fuel, they use atmospheric oxygen to burn out the fuel, making them more efficient and extremely fast. Scramjets have long been a theoretical possibility, but in 2002 Scientists at the University of Queensland, Australia and at the UK defense company Qinetiq successfully completed the first flight of scramjet vehicle. Although the test simply demonstrated the technology and not a practical engine system, the vehicle reached Mach 7, which is seven times the speed of sound.

NASA in Scramjet:

     Since then, the National Aeronautics Space Administration (NASA) has been working on its Hyper-X program to develop scramjets into a practical technology, able to provide the thrust to propel a craft. It is believed the technology could eventually allow vehicles to reach Mach 15, reducing an eighteen hour flight from New York to Tokyo to just two hours.

Joint Project for Scramjet:

     In 2007 a joint project between the U.S Defense Advanced Project Agency (DARPA) and the Australian Defense Science and Technology Organization (DSTO) launched a flight that succeeded in reaching the hypersonic speed of Mach 10. the imminent arrival of these hypersonic airplanes will make the world a much smaller place.

Achievement:

     In 2004 the NASA X-43A Scramjet achieved a record of Mach 9.6, nearly 7,000 miles per hour (11,265 kph).

Quotes:

     "We..believe that a hypersonic airplane could be a reality in the not too distant future."

                                                             -Dr.Steven Walker, DARPA Tactical Technology Office 

Text Credit : The Internet Age | Scramjet | 1001 Inventions that changed the World

Science in History - Scramjet | Satellite Radio Communication 2001

 

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Space Probe 1959

The Soviet boost our knowledge of space

Space Probe:

     A Space probe is a satellite that leaves the grip of Earth's gravity and moves off to flyby, or orbit, another solar system body. The first target was the Moon. There were three U.S attempts in 1958 | Pioneer-1 | Pioneer-2 | Pioneer-3 | which all failed. The U.S.S.R had the first three success in January 1959 with the Luna-1 probe, which was launched with the objective of impacting the lunar surface. It flew by, missing by 5,590 km but at least it got three. The U.S's Pioneer 4 flew past at a miss distance of 60,000 km.

Successful Space Probes:

    The greatest early successes were Luna-2 in September 1959 and Luna-3 in October 1959, the first hitting the moon just east of the sea of Serenity and the second imaging the far side of the moon for the first time. The 1960s saw a host of lunar missions that was to culminate in the first moon landing.

First Successful Planetary Probe:

     The first successful planetary space probe reached Venus in 1962 and the USSR's Venera-7 probe soft landed there in 1970. In June and August 1976 the US's Viking-1 & Viking-2 probes achieved the first successful landings on Mars and returned images from the planet's surface. Voyager-1 & Voyager-2 have since become interstellar space probes and are on their way to the stars.

Quotes:

     "We have your satellite. If you want it back send twenty billion in Martian Money"

                                                                - Graffiti at NASA Laboratory, Pasadena, California.

Text Credit : Inventions that Changed the World

Science in History : Space Probe | Scramjet | Satellite Radio Communication

Tags : Voyager-1 | Voyager-2 | Luna-1 | Luna-2 | Luna-3 | Pioneer-1 | Pioneer-2 | Pioneer-3 |

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Satellite Radio Broadcasting 2001

XM revolutionizes radio broadcasting:

Idea of Broadcasting:

      How often have you been listening to your favourite radio station in your car, only to have it slowly dwindle away as you drive out of range of the transmitter? The answer to this problem came in 2001 when a new way to receive radio is made its debut -  a national service beamed from outer space that, in return for a subscription free, offered 100 different channels, none of which would be interrupted by poor reception.

Broadcasting through Satellite:

     The Coverage, provided by two or three high-orbit satellites, came as a strong signal requiring no satellite dish, just an antenna the size of the match box. Although the broadcast could be dampened by sky scrappers or long tunnels, the signal was bolstered by transmissions from ground based towers.

XM and Sirius Initiative:

     Two companies were originally granted licenses to provide satellite radio in 1997 : XM and Sirius, with XM getting off the mark first in the US in September 2001 and the Sirius following in 2002. For the monthly subscription fee of $10 the Xm Service offered a wide choice: some channels were dedicated to specific topics such as news, sports, traffic and weather reports; music channels had no commercials and even no DJ's, and talk shows were less censored than the free terrestrial radio broadcasts.

Audience at First:

     What is more, satellite radio receivers displayed the name of each artist and songs as it played. Soon receivers were being made that could be taken out of cars and carried into the home.Initial uptake was slow. At launch it was estimated that there were only four listeners per channel, but by 2008 a total audience of over 16 million had been garnered. Despite legal wrangles over music copyright and complaints about the content of some chat shows, it seems that satellite radio is here to stay.

Text credit : The Internet Age | Page 927 | 1001 inventions that changed the world | ISBN 978-93-5009-685-7 

Science in History - Satellite Radio Broadcasting 2001 

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