CHANDRAYAN

Chandrayan - I   Launch

After the successful launch of Chandrayan - 1 ISRO plans to launch Chandrayan - II by 2013. The unfortunate technical glitches of Chandrayan 1, ISRO is planning to march ahead in it’s space endeavour with Chandrayan 2, to be launched in 2013. The sole space research organization of the country has given confirmation that if everything goes smoothly; it’s going to launch Chandrayan 2.


Still there are some technical modifications to be done in the indigenously developed cryogenic engine, which will power the Geostationary Satellite Launch Vehicle (GSLV), ISRO is hopeful that the shortcomings of the device will be eradicated as soon as possible and the launching of Chandrayan-2 will take place in the scheduled year of 2013. All these information were released by the Chairman of ISRO, Dr. K. Radhakrishnan, while he was in a visit to Indian Statistical Institute, Kolkata, on the eve of Statistics Day.

According to sources, the testing of the cryogenic engine will be done in the next year, after the necessary modifications are done. Dr. Radhakrishnan also revealed that ISRO is developing a unique kind of next generation satellite, equipped with such instruments, which will enable to trace the greenhouse gases and will help us to understand the atmospheric chemistry in a much better way. He is very hopeful that such big strides undertaken by ISRO will be very helpful in understanding climate change.

Photos took by chandrayan -1 (Moon)

"The Chandrayaan-II we are planning to have in the year 2013. By that time, we should have our GSLV (Geosynchronous Satellite Launch Vehicle) flying with the Indigenous Cryogenic Engine Stage. That is the target with which we are working," said Radhakrishnan.
Radhakrishnan said some snags have been identified in flight-testing of the Indigenous Cryogenic Engine, which are being analysed and would be sorted out in approximately a year
"We went through a very detailed analysis as to what happens and why it happens and we have come to a couple of scenarios in which such a snag would have occurred. Our immediate task is to confirm that through testing on the ground and then prepare for the next flight testing. This should happen in a year from now," he added.The Chandrayaan-II is the second unmanned lunar exploration mission that ISRO is pursuing.

History of Telephone Technology

HISTORY OF TELEPHONE TECHNOLOGY

Service Lines and Switchboards


In 1877, construction of the first regular telephone line from Boston to Somerville, Massachusetts was completed. By the end of 1880, there were 47,900 telephones in the United States. The following year telephone service between Boston and Providence had been established. Service between New York and Chicago started in 1892, and between New York and Boston in 1894. Transcontinental service by overhead wire was not inaugurated until 1915. The first switchboard was set up in Boston in 1877. On January 17, 1882, Leroy Firman received the first patent for a telephone switchboard.


Exchanges and Rotary Dialing
The first regular telephone exchange was established in New Haven in 1878. Early telephones were leased in pairs to subscribers. The subscriber was required to put up his own line to connect with another. In 1889, Almon B. Strowger a Kansas City undertaker, invented a switch that could connect one line to any of 100 lines by using relays and sliders. This switch became known as "The Strowger Switch" and was still in use in some telephone offices well over 100 years later. Almon Strowger was issued a patent on March 11, 1891 for the first automatic telephone exchange.
The first exchange using the Strowger switch was opened in La Porte, Indiana in 1892 and initially subscribers had a button on their telephone to produce the required number of pulses by tapping. An associate of Strowgers' invented the rotary dial in 1896 which replaced the button. In 1943, Philadelphia was the last major area to give up dual service (rotary and button).