This is the famous pale blue dot image captured by Voyager 1 at a distance of 6 billion kilometers, depicting Earth as a tiny pixel. This photograph was taken before many of you were even born, but the ingredients and substances that shaped us are all present in the tiny blue dot that we name home.
However, this date is important. Just 34 minutes after this photograph was taken, the cameras were permanently turned off, leaving Voyager 1 blind. Since then, the spacecraft has reached a distance of 24 billion kilometers from Earth, making it the farthest man-made object in space. However, why were the cameras disabled? And what would it take to reactivate them? Also, at the end of this movie, this amazing Lego Space Shuttle set will be given away. Therefore, remain to see how you can win! During their stay in space, the Voyager spacecraft have broken numerous records. Not only are they the most distant objects in space, but they have also been in operation for nearly 45 years.
It’s hard to believe that computers and systems made on Earth in the 1970s are still working after being in the harsh environment of space for so long. The camera system on Voyager 1 is a great example of the cutting-edge technology on board. The Voyager 1 is equipped with two vidicon cameras, which are essentially very early television cameras that convert analog to digital signals. The effective resolution was 800 by 800 pixels, and 8-bit grayscale images were captured. One had a wide-angle lens that could take pictures of the planets with a lot of detail as the probe got close to them. The other had a zoomed-in lens with a tiny field of view that could catch the finer details of each planet viewed, as well as glance back at our solar system as it shrank on the horizon.
Before reaching these cameras, however, the light passed through an optics system that allowed it to produce colorful images. This filter wheel comprised orange, violet, blue, and green filters. Voyager would capture numerous photographs of its subject using each filter. As light flowed through the filter, only light of that particular color would pass through, while light of all other colors would be absorbed. The photographs were still captured in grayscale, but each contained patches of varying brightness where the light was more sensitive to a particular color. After being transmitted to Earth, these photos were saturated with their respective filter colors and merged to make a full-color image. Our eyes include three color-sensing cones—red, green, and blue—which, when combined, allow us to perceive a spectrum of colors.
However, the true magic of Voyager occurs within the vidicon tube. After passing through the lens and the filter wheel, the light enters the vidicon tube. The photons initially strike a see-through faceplate constructed of tin-oxide, which has a photoconductive target plate immediately behind it. When photons strike the object, free electrons are produced. The greater the intensity of light at a given spot, the greater the production of free electrons. The faceplate then attracts these liberated electrons, leaving the target plate with gaps. The image is then scanned by a cathode at the back of the tube firing electrons at the target plate. These electrons reach the target plate and fill the resulting voids to generate an electric current. This image data-containing signal can now be relayed back to Earth.
However, transferring data from billions of kilometers distant is extremely complex and many things might go wrong. We have observed how the Voyager’s cameras turn light into a signal, but what occurs next? Each photograph recorded by Voyager required approximately 5 million bits of information, or just over a half megabyte. This may not seem like much by today’s standards, but when your spacecraft is billions of kilometers distant, it is incredibly difficult to convey this data back. When Voyager 1 was significantly closer to Earth, its greatest data rate was approximately 115,000 bits per second. At this rate, it would take around 43 seconds to transmit a complete image to Earth. At the current transmission rate of approximately 160 bits per second, it would take nearly 8 hours to transmit a single image. In addition, Voyager 1 is currently 23 billion kilometers away, therefore it would take 21 hours for that signal to reach us.
Since the camera can produce an image significantly faster than it can transfer data, the vidicon camera stores its signal on magnetic tape. This information accumulates over time and can be relayed whenever Voyager 1 has a strong connection to Earth. But why hasn’t the camera aboard Voyager been activated in almost 30 years? To answer this question, we must determine where Voyager 1 was when it snapped its final image. The image of the iconic pale blue dot was captured from a location 6 billion kilometers from Earth. At this moment, the distance between the spaceship and its surroundings was so great that everything appeared as a small dot.
Additionally, the spacecraft was on a trajectory that would make it the first to depart the solar system and enter interstellar space. To determine when this occurred, the team intended to prioritize the equipment that could detect interstellar plasma, an indication that Voyager 1 had left the solar system. At this time, Voyager 1 was 13 years old, and it would be decades before it reached interstellar space. Therefore, in order to continue communicating with the spacecraft at that point, engineers had to substantially prolong its lifespan. Similar to many other spacecraft, Voyager 1 is powered by an RTG that converts the heat from a radioactive substance into electricity. Each year, the power production declines by approximately 4 Watts, and Voyager 1 is now producing only 57% of its initial power output.
The camera system alone consumes little more than 40 watts of energy. To purchase more time for the spacecraft, the crew began turning off different Voyager equipment to lower its power consumption. To conserve memory, the scientists also disabled the camera-operating software from the Voyager spacecraft. The computers and software that were utilized to examine the photographs on Earth no longer exist. Due to the cameras and their heaters having been exposed to the harsh temperatures of outer space for decades, it is possible that they would no longer operate.
What would the cameras see if they were turned back on, assuming they were in good condition? Many believe that Voyager 1 is so far from the sun that it will be completely in the dark, however this is not the case. Even if the sun is now 23 billion kilometers distant, its light is still 16 times brighter than the Moonlight here on Earth, therefore it is still possible to read a book. However, there is nothing surrounding Voyager that is fascinating or large enough to photograph. If Voyager were to capture a photograph today, it would be nighttime, but you would still be able to see the sun and other planets as small, dim pixels.
Despite traversing 23 billion kilometers, the star constellations in our sky would appear identical. This is maybe the most amazing fact. If Voyager desired a different perspective on our galaxy, it would have to travel thousands of light years to detect a minor movement in the stars. Voyager 1 will finally accomplish this, after we have been gone for millions of years and long after we have lost communication with the spacecraft.
