The unmanned NASA/JPL space probe Mariner 9 concludes its mission to map the surface of Mars. After spending more than a year as the first human spacecraft to orbit another planet in the solar system, Mariner 9’s fuel supply has run out, but not before it has obtained over 7,000 images of the surface of Mars, discovering gigantic volcanoes and huge canyons in the process. The detailed photography returned by Mariner 9 is a vitally important tool for scientists and mission planners already hard at work on a potential robotic landing mission to Mars, to be launched later in the 1970s. Though inactive, Mariner 9 remains in orbit of Mars.
The 18th episode of The Sixth Sense airs on ABC, starring Gary Collins. John Hillerman (Magnum P.I.) guest stars.
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NBC airs the 33rd episode of Night Gallery, an anthology series of original short plays and short story adaptations hosted by Rod Serling. Sandra Dee guest stars.
NBC airs the eighth episode of the supernatural anthology series Ghost Story, produced by 1960s horror movie mogul William Castle and starring Sebastian Cabot. Pamela Franklin and Eleanor Parker guest star. (This series will be retitled Circle Of Fear in 1973.)
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Service Electric Cable, the local cable company in Wilkes-Barre, Pennsylvania, embarks on an ambitious experiment, launching a movie channel that only a few hundred of their subscribers pay extra to receive. The channel, Home Box Office, is the brainchild of a New York City broadcasting entrepreneur seeking a workaround for the tendency of the city’s own high-rise architecture to block over-the-air signals. Originally code-named the Green Channel (presumably for the cash it is hoped it will rake in), HBO begins life with a mix of movies and live sports events (such as pro hockey) with no commercial interruption. Within a year, HBO will be acquired by Time-Life, expanding to nine hours of programming every day. With HBO having proven that cable subscribers will pay extra for an ad-free movie and sports channel, competing pay cable networks such as Showtime will spring up in the years to come. HBO also pioneers the concept of broadcasting exclusively via satellite, years ahead of the broadcast networks.
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NASA launches Explorer 48, renamed Small Astronomy Satellite B, from an Italian-owned offshore launch platform off the coast of Kenya. SAS-B is a smaller spacecraft than NASA’s larger Orbiting Astronomical Observatory (OAO) series, but can be aimed very precisely at any gamma ray sources that it detects. One of those sources turns out to be the pulsar remnant of a massive supernova, a discovery later named Geminga. An electrical fault will end SAS-B’s functionality in 
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NBC airs the tenth episode of Leslie Steven’s “spy-fi” series Search, starring Hugh O’Brian and Burgess Meredith. Joanna Cameron (The Secrets of Isis) guest stars.
The Soviet space program, still determined to reach the moon, again loads an unmanned Soyuz/Korabl capsule and lander combo onto the huge N1 rocket for another test launch. At an altitude of nearly 25 miles, the N1 experiences severe structural stresses and disintegrates in mid-air, effectively ending the Soviet drive for the moon. Another N1 is prepared for another launch, with an eye toward orbiting a massive space station with which to upstage the upcoming American Skylab station, only to be dismantled on the ground in favor of more reliable launch vehicles.
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Atari releases its first product, the arcade game 
The final manned lunar landing mission lifts off atop a Saturn V rocket. Apollo 17 is the first mission to include a qualified geologist, Harrison Schmitt, in its crew; Gene Cernan and Schmitt descend to the surface aboard the lunar lander Challenger, where the last two men to walk on the moon spend a total of 22 hours exploring the Taurus-Littrow valley. For the third mission in a row, a lunar rover is stowed into one side of the lander. Astronaut Ron Evans orbits overhead in the command/service module America. The astronauts return on December 19th, bringing home nearly 250 pounds of lunar soil and rock samples.