The telecommunication capability also diminished with distance, limiting the number of data modes that could be used by the imaging system. The challenge was that, as the mission progressed, the objects to be photographed would increasingly be farther away and would appear fainter, requiring longer exposures and slewing (panning) of the cameras to achieve acceptable quality. Both cameras are of the slow-scan vidicon tube type and were fitted with eight colored filters, mounted on a filter wheel placed in front of the tube. Voyager 1 's Imaging Science Subsystem (ISS) consists of two cameras: a 200 mm focal length, low-resolution wide-angle camera (WA), used for spatially extended imaging, and a 1500 mm high-resolution narrow-angle camera (NA) – the one that took Pale Blue Dot – intended for detailed imaging of specific targets. A proposal to continue to photograph Earth as it orbited the Sun was rejected. Finally, NASA Administrator Richard Truly interceded to ensure that the photograph was taken. It was not until 1989 that Sagan's idea was put in motion, but then instrument calibrations delayed the operation further, and the personnel who devised and transmitted the radio commands to Voyager 1 were also being laid off or transferred to other projects. Īlthough many in NASA's Voyager program were supportive of the idea, there were concerns that taking a picture of Earth so close to the Sun risked damaging the spacecraft's imaging system irreparably. He acknowledged that such a picture would not have had much scientific value, as the Earth would appear too small for Voyager 's cameras to make out any detail, but it would be meaningful as a perspective on humanity's place in the universe. When the spacecraft passed the planet in 1980, Sagan proposed the idea of the space probe taking one last picture of Earth. Voyager 1 was expected to work only through the Saturn encounter. Since its launch, it receives routine commands and transmits data back to the Deep Space Network. Its mission has been extended and continues to this day, with the aim of investigating the boundaries of the Solar System, including the Kuiper belt, the heliosphere and interstellar space. The spacecraft, still travelling at 64,000 km/h (40,000 mph), is the most distant human-made object from Earth and the first one to leave the Solar System. Voyager 1 was the first space probe to provide detailed images of the two largest planets and their major moons. After the encounter with the Jovian system in 1979 and the Saturnian system in 1980, the primary mission was declared complete in November of the same year. In September 1977, NASA launched Voyager 1, a 722-kilogram (1,592 lb) robotic spacecraft on a mission to study the outer Solar System and eventually interstellar space. Over the years, the photograph has been revisited and celebrated on multiple occasions, with NASA acknowledging its anniversaries and presenting updated versions, enhancing its clarity and detail. After fulfilling its primary mission and as it ventured out of the Solar System, the decision to turn its camera around and capture one last image of Earth emerged, in part due to Sagan's proposition. The photograph was captured by Voyager 1, a spacecraft launched in 1977 with the initial purpose of studying the outer Solar System. Commissioned by NASA and resulting from the advocacy of astronomer and author Carl Sagan, the photograph was interpreted in Sagan's 1994 book, Pale Blue Dot, as representing humanity's minuscule and ephemeral place amidst the cosmos. In the photograph, Earth's apparent size is less than a pixel the planet appears as a tiny dot against the vastness of space, among bands of sunlight reflected by the camera. Pale Blue Dot is a photograph of Earth taken on February 14, 1990, by the Voyager 1 space probe from an unprecedented distance of approximately 6 billion kilometers ( 3.7 billion miles, 40.5 AU), as part of that day's Family Portrait series of images of the Solar System. Seen from about 6 billion kilometers (3.7 billion miles), Earth appears as a tiny dot within deep space: the blueish-white speck almost halfway up the rightmost band of light.
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