Space Probes To Planets Of Other Stars: Episode 1

Space probes to planets of other stars - 1
The distances separating the stars are so enormous that it is even difficult to imagine them. Suffice it to say that taking as reference the average separation between the Earth and the Sun, the so-called Astronomical Unit (AU), equal to 149.6 million kilometers, the distance that separates us from the nearest star, Proxima Centauri, is 266,000 times greater, that is 103 million times the distance Earth-Moon. Even a ray of light, which moves at the maximum speed allowed by the known laws of physics, takes 4.2 years to reach us from Proxima Centauri, while less than 8 and a half minutes is enough to fill the space that separates us from the Sun.
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In these numbers, in their relentless inevitability, is enclosed the problem of interstellar travel. If we then take into account the dimensions of our Galaxy (about 100,000 light-years in diameter) and those of the observable Universe (more than 10 billion light-years), the question of trips in the deep cosmos can only leave us dismayed.
Nevertheless, especially since the fifties, several scientists have accepted this exceptional challenge, facing it with great passion and extraordinary inventiveness. Of course, the problems to be solved were and still remain enormous, but there is one thing that not everyone knows: the first interstellar journeys, however rudimentary, have already begun!
At this moment, there are space vehicles that have already gone beyond the known boundaries of the Solar System. These are the automatic probes launched by NASA for the exploration of giant planets, and thanks to the trajectory chosen for their mission, they have gained enough energy to escape permanently from the gravitational grip of the Sun.

The first to leave the Earth, in 1972, was Pioneer 10, destined to fly over Jupiter. The last signal received was on January 23, 2003, when it was 80 UA from the Sun. At the moment it is 122 UA away, and at a speed of 12 km/s, it is heading towards the constellation Taurus. It will pass relatively close to a star in 2 million years, but at that point it will be only an inert wreck. In the extremely unlikely event that the probe is detected and recovered by an alien civilization, it will tell its story through the famous gold plate onboard, designed by Carl Sagan and Frank Drake.
The twin Pioneer 11, launched in 1973 to Jupiter and Saturn, ran out of energy at the end of 1995 and has been silent ever since. But it also carries onboard the gold plate and in 4 million years it will pass in the vicinity of a star of the Eagle constellation.
The other two messengers of Humanity among the stars are the automatic vehicles Voyager 1 and 2. Both launched in the late summer of 1977 to explore the systems of Jupiter and Saturn (and in the case of Voyager 2 also those of Uranus and Neptune), they have brilliantly surpassed all the most optimistic forecasts of their operation, so much to reach and exceed the boundaries of the heliosphere after a journey that lasted tens of years. The two Voyagers have sufficient energy and propellant reserves for attitude control to ensure their operation until about 2025. But even as "deax", the two probes will continue their unstoppable journey through the stars, moving away by 3.5 UA per year on Voyager 1 and 3.1 UA per year on Voyager 2. In the remote but always possible eventuality that during their wandering through the Galaxy they will be intercepted and studied by an extraterrestrial spaceship, the two Voyager also carry onboard a message of ours: a golden copper disk, 30 centimeters in diameter, containing a phonographic recording of images and sounds, chosen to represent us and our planet. Each disc is housed in an aluminum case, together with a reading device.

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Credits: Mark A. Garlick / markgarlick.com
Credits: Ron Miller
Credits: Nasa/Shutterstock/Storyblocks/Elon Musk/SpaceX/ESA
Credits: Flickr
Credits: ESO

Video Chapters:
00:00 Introduction
00:57 Overview
01:41 First Interstellar Journey
02:59 Other Two Messengers
05:47 Ionic Engines
08:16 Interstellar Arches

#insanecuriosity #voyager2 #interstellarspace