In our previous two articles, we discussed Pioneer 10 and 11, its need and working. Today we will cover briefly The Pioneer Plaque, which was sent in both the Pioneer missions in hope of finding extra-terrestrial life.
The Pioneer Plaque
The original idea, that the Pioneer spacecraft should carry a message from mankind, was first mentioned by Eric Burgess an English freelance consultant, lecturer, and journalist, who wrote about the Pioneer program of space missions since the first tests in 1957. Carl Sagan and Frank Drake designed the plaque, and the artwork was prepared by Linda Salzman Sagan, who was Sagan’s wife at the time. The first plaque was launched with Pioneer 10 on March 2, 1972, and the second followed with Pioneer 11 on April 5, 1973.
Hyperfine transition of neutral hydrogen
At the top left of the plaque is a schematic representation of the hyperfine transition of hydrogen, which is the most abundant element in the universe.
Figures of a man and a woman
On the right side of the plaque, a man and a woman are shown in front of the spacecraft. The right hand of the man is raised as a sign of goodwill. Although this gesture may not be understood, it offers a way to show the opposable thumb and how the limbs can be moved.
Sun and galactic landmarks
The radial pattern on the left of the plaque shows 15 lines emanating from the same origin. Fourteen of the lines have corresponding long binary numbers, which stand for the periods of pulsars, using the hydrogen spin-flip transition frequency as the unit. Since these periods will change over time, the epoch of the launch can be calculated from these values.
At the bottom of the plaque is a schematic diagram of the Solar System. A small picture of the spacecraft is shown, and the trajectory shows its way past Jupiter and out of the Solar System.
Silhouette of the spacecraft
Behind the figures of the human beings, the silhouette of the Pioneer spacecraft is shown on the same scale so that the size of the human beings can be deduced by measuring the spacecraft.
Source for all images: NASA
The next article will be on the third artificial object to leave the Solar System!