On September 5,1977,NASA launched Voyager 1 spacecraft to study the outer solar system and interstellar medium. On February 17,1998,it became the most-distant man-made object in space. This month,35 years and six months after its launch,this 722-kg space probe is more than 11 billion miles (18 billion kilometres) from Earth marking another milestone in human space exploration by entering a previously unknown region of space,either already outside our solar system or about to cross that bridge.
The Voyager mission was designed to take advantage of a rare geometric arrangement of outer planets in the late 1970s and 1980s. This layout of Jupiter,Saturn,Uranus and Neptune,which occurs about every 175 years,allows a spacecraft on a particular flight path to swing from one planet to the next without the need for large onboard propulsion systems.
Voyagers 1 has since surprassed even the most hopeful expectations of its mission director,even as it continues to receive routine commands and transmit data back to the Deep Space Network. Like its sister craft Voyager 2,the spacecraft is now tasked with locating and studying the boundaries of the solar system.
ANYBODY OUT THERE?
Both Voyager spacecrafts carry a greeting to any form of life,should that be encountered. The message is carried by a phonograph record a 12-inch gold-plated copper disk containing sounds and images selected to portray the diversity of life and culture on Earth. The contents of the record were selected for NASA by a committee chaired by Carl Sagan. Dr Sagan and his associates assembled 115 images and a variety of natural sounds. To this they added musical selections from different cultures and eras,and spoken greetings from Earth in 55 languages.
DID YOU KNOW?
* $865 million: The total cost of the Voyager mission from May 1972 through the Neptune encounter was $865 million.
* 11,000 workyears: Workyears devoted to the project till the Neptune encounter. This is equivalent to one-third the amount of effort estimated to have been taken to complete the Great Pyramid at Giza to King Cheops.
* 5 trillion: A total of five trillion bits of scientific data had been returned to Earth by both Voyager spacecraft at the completion of the Neptune encounter.
* 2000 colour TV sets: Each Voyager has the equivalent electronic circuit complexity of some 2000 colour TV sets