Until 1970s, astronomers had observed the two outer planets of the solar system only through telescope and there were still many mysteries to unravel about both the planets. National Aeronautics and Space Administration, i.e. NASA, conceived a mission then to know more about these planets. To accomplish the objectives, two spacecraft- Voyager 1 and Voyager 2, were built to fly-by these planets and conduct close up studies of the planets and their moons.

The space crafts were to go quite far away from sun to conduct their studies, so the solar intensity was too low to use solar cells to generate the electricity for the spacecraft. Hence each spacecraft was powered with three thermoelectric generators, which, by converting the heat energy generated by the decay of the radioisotope Pu-238 to power source. The spacecraft was equipped with the on-board instruments like UV scanners, television cameras, IR scanners , plasma detectors and cosmic ray detectors.

@ https://voyager.jpl.nasa.gov/mission/spacecraft/interactive.php ) A very beautiful 3D image of this spacecraft can be found at NASA official site for Voyager (Ref.

Fig: The Voyager Spacecraft (Courtesy: NASA)

Voyager 2 was launched on 20th August, 1977 and its twin spacecraft Voyager 1 on 5th September, 1977. Initially, the mission was for five years but it was extended further to include the other two planets Neptune and Uranus. The extension in the lifetime was done with the help of remote controlled re-programming.

Communication to the spacecraft was done through Deep space network sites equipped with giant radio antennas. These were strategic sites equidistant from each other, approximately 120˚ on the longitude ensures that there is constant communication with the spacecraft.

By 1990, both the spacecraft had explored all the four outer planets of our solar system and made astonishing discoveries.

Now after completing the exploration of the four planets, the spacecraft are continuing their journey far beyond the solar system into the interstellar space, i.e., the space between the stars. As of now the Voyager 1 is in "Interstellar space" and Voyager 2 is currently in the "Heliosheath". On 25th August 2012, Voyager 1 left the solar system and entered the interstellar space. Voyager 2 is expected to do so in few years. Distance of Voyager 1 as on April 21, 2018 was 13,135,137,764 mi and that of Voyager 2 was 10,890,847,362 miles from earth. The spacecraft are speeding away from the solar system at the rate of about 54,000 kmph and astronomers estimate that Voyagers have enough electrical power to operate at least until 2020 by which time they will be 22.1 and 18.4 billion km from the sun respectively. It is interesting to note that no communication will be possible thereafter. Barring any catastrophic collision, they are expected to continue their boundless journey on their own in the vast expense of space.

The most interesting part of the Voyagers is the Golden Disk it has been equipped with. We always talk about the existence of Aliens, and till now there is no as such proof of the existence of the any other species in any other planet which are as intelligent as humans. Now, to get over this curiosity Voyagers are to do a fascinating task of communicating the story of our planet Earth to the extra- terrestrials, who might one day find this spacecraft.





Fig: Golden Disk (Courtesy: NASA)

Fig: Explanation of the cover diagram on the disk

Each spacecraft carries a Golden Disk, which is like a time capsule, consisting of a phonograph

record on a 12 in gold plated copper discs. The record is encased in a protective Aluminium jacket with a cartridge and a needle. One side of the record depicts, in symbolic language, the origin of the spacecraft with the reference to 14 pulsars whose positions in the universe and the pulsation periods are precisely known. On the same side it is also depicted how the record is to be played. The recording consists of picture of various parts of the globe, along with various human activities and the audio consisting of variety of natural sounds on earth. The music from India is a 3.5 minute piece with lyrics “Jaat kahan ho akeli gori”.It also consists of spoken greetings by people from various parts of globe.







Written By-



Nitin Kumar Singh



