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Space Topics: Past MissionsPhobos 2
Phobos 2 launched toward Mars on July 12, 1988. It was designed to orbit Mars and study Phobos, the larger and inner of Mars' two moons. The mission included a "hopper" that was to land on the surface of Phobos as the spacecraft hovered above it. Phobos 2 successfully went into orbit on January 29, 1989, and began sending back preliminary data. Several sets of images were returned on February 21 and 28, as Phobos 2 orbited Mars in a path coplanar with the orbit of the moon, but 300 kilometers (180 miles) farther from Mars. Because of the larger distance from Mars, Phobos 2 traveled more slowly than the moon, so images were only possible during "flybys" that occurred once a week. Next, the spacecraft adjusted its orbit so that its orbital period was the same as that of Phobos, allowing it to remain stationed within 500 kilometers (300 miles) of the moon. Five more sets of images were acquired on March 25. Then, on March 27, just before the spacecraft was to move within 50 meters of Phobos and deploy the two landers, the spacecraft's onboard computer malfunctioned and the mission was lost.Although the mission failed in most of its objectives, it succeeded in sending back 37 images of Phobos, many of them at higher resolution and under better viewing conditions than had been achieved by previous missions including Mariner 9 and the Viking orbiters. Phobos 2's images included the data necessary to compose striking color views of the coal-black moon against the colorful orange disk of Mars. Images of Phobos and Mars from Phobos 2These are a few of the 13 sets of images acquired by the Phobos 2 mission before it was lost. The images of Phobos against Mars make it clear how much darker the (likely) ancient captured asteroid is in comparison to the bright, dusty surface of the planet.
The Complete Phobos 2 VSK Data SetClick here to view the complete Phobos 2 VSK raw data set. Phobos-2's camera system, the videospectrometic system or VSK, was a three-channel, color television camera. During its mission to Mars, Phobos 2 took 37 images of Phobos at distances ranging from 190 to 1,100 kilometers. Though few in number, they complemented the preexisting images of Phobos captured by Mariner 9 and the Viking orbiters, filling in some details at high resolutions and providing observations at a greater range of wavelengths and additional phase angles. The VSK imaging campaign at Phobos was intended to map all of Phobos at resolutions of tens of meters per pixel, and provide very high-resolution views of from a hovering position only 50 meters above the moon's surface. Unfortunately, the loss of the spacecraft prevented the highest-resolution imaging from taking place. One of the three VSK channels achieved broadband, high-resolution images, while the other two captured color information at lower resolutions:
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