IAC-19-F4.1.8 The Family Portrait of the solar system: The last set of images taken by Voyager 1 and the fascinating story of how they came to be

摘要

On Valentine's Day, 1990 February 14, the Voyager-1 spacecraft executed a 60-image mosaic of portions of the Solar System, that came to be known as "The Family Portrait". The set of observations was the 6th request by the Voyager Imaging Science Team, and Mission Planning Office. The fascinating story of why it took 8 years and 6 (ultimately 7) requests to gain approval has never been told.The Family Portrait taken by Voyager 1 remains the first, and still the only time, a spacecraft has attempted to photograph our home Solar System. Only 3 spacecraft have been capable of such an observation, Voyager 1, Voyager 2, and New Horizons. New Horizons just completed its second target body encounter in 2019 January. The observation opportunities have been few and far between in human history.The first Voyager-1 observation request consisted of a single set of 3 Wide Angle camera images of the Earth, and whatever other planetary objects occurred in the frame at the time. The Voyager Project denied the request, for many reasons. The next 3 requests followed this same observation design, with minor variations, with all disapproved. The 6th request intended to image 7 of the then 9 planets (all but Mercury and Pluto). The Voyager Project approved this request. The observation imaged 6 planets, with Mars too dim to detect. A 7th request intended to replicate the Voyager-1 observations on Voyager 2, but the Voyager Project denied this request.The Observation design consisted of slewing the cameras to Neptune, taking Narrow Angle images through 3 separate color filters plus 1 Wide Angle context image, taking a set of Wide Angle images from Neptune to Uranus, repeating the Narrow and Wide Angle images at Uranus, then stepping in turn to Saturn, Mars, Jupiter, Earth, and Venus. The observation concluded with a set of Wide-Angle context images around the Sun, with the final two images taken of the Sun itself.This paper discusses in depth the history of the 7 observation requests, the individuals involved in conceiving the various aspects of the ultimately successful observation set, the challenging spacecraft and project resource constraints, the resulting observation design and the phenomenal results. The image of Earth, the iconic Pale Blue Dot, shows us how small, tiny, and vulnerable "spaceship Earth" remains in the vast cosmos in which we live.