The Voyager 1, which was launched from Earth in 1977, is soon going to be the first man-made object to exit our solar system, NASA reports.
According to NASA scientists, the spacecraft will leave the solar system in next one or two years, much sooner than previously thought.
"We are approaching the solar system's frontier," said Ed Stone, Voyager project scientist at California Institute of Technology in Pasadena, in a press statement.
"The laws of physics say that someday Voyager will become the first human-made object to enter interstellar space, but we still do not know exactly when that someday will be," said Stone.
NASA, based on the data it has received from the spacecraft, announced last week that Voyager 1 is very near to the "heliopause," the border between our solar system and deep space where solar winds stop, says NASA research scientist Eric Christian in Greenbelt, Md.
"Voyager has entered the final lap on its race to the edge of interstellar space, as it begins exploring the solar system's final frontier," Stone added. "The latest data indicate that we are clearly in a new region where things are changing more quickly. It is very exciting."
The latest set of data has been picked up by the Voyager's High Energy telescopes and shows the 11.1 billion-mile journey from Voyager 1 to the antennas of DSN revealing the number of charged particles.
"From January 2009 to January 2012, there had been a gradual increase of about 25 percent in the amount of galactic cosmic rays Voyager was encountering," said Mr. Stone. "More recently, we have seen very rapid escalation in that part of the energy spectrum. Beginning on May 7, the cosmic ray hits have increased five percent in a week and nine percent in a month."
Scientists are dealing with three data sets which will indicate whether Voyager 1 has left the solar system. Apart from the latest data set, a second set of data reveals the intensity of energetic particles inside the heliosphere and the third and final set will provide evidence of Voyager's exit from the solar system.
In November 2003, the Voyager team reported that the spacecraft entered new frontier called the termination shock region and was experiencing unusual events that were never encountered before in the mission's 26-year history.
"Voyager's observations over the past few years show that the termination shock is far more complicated than anyone thought," said Dr. Eric Christian, Discipline Scientist for the Sun-Solar System Connection research program at NASA Headquarters, Washington, DC.
At the termination shock, the solar wind slows abruptly from its average speed of 300 to 700 km per second (700,000 - 1,500,000 miles per hour) and becomes denser and hotter, NASA informs.
But now the spacecraft has passed through the termination shock region and has entered into the heliopause region where there's a vast, turbulent expanse, the Sun's influence ends and the solar wind crashes into the thin gas between stars.
"When the Voyagers launched in 1977, the space age was all of 20 years old," said Mr. Stone. "Many of us on the team dreamed of reaching interstellar space, but we really had no way of knowing how long a journey it would be - or if these two vehicles that we invested so much time and energy in would operate long enough to reach it."
According to NASA, Voyager's instruments are now old and many are dead but they will still be collecting and transmitting data for another 20 or 30 years.
