On August 6, 2014, the ESA spacecraft (European Space Agency) Rosette ended his 10-year journey to comet 67P Churyumov-Gerasimenko, becoming the first spacecraft to ever reach a comet orbit. The mission will approach its highest point in November, when the “Phil” robot landing module is released to the surface. The goal is to drill the surface while Rosette and the comet come close to the Sun. Although the mission came closest to the goal, this is not the first robotic probe that tried to contact the comet. Consider the remaining 7 meetings.
Undoubtedly, the brightest object in history is Halley's comet, which all space agencies aimed in 1986 during its 75-76-year-old orbit through the inner part of the Solar System. Then there was still little known about such travelers. In October of the same year, the mission of the European Space Agency Giotto visited the 15-kilometer Halley comet. The probe, weighing half a ton, passed within 600 km (373 miles) of the comet's nucleus, capturing the tail and coma (gas around the nucleus). It was this mission that confirmed what comets are made of: dust and flying ice. And although Giotto managed to get as close as possible, two Russian-French probes (Vega 1 and 2) and two Japanese ships Suissey observed a distance from the comet.
Something reminded Comet Borelli's previous object. Its size reached half the volume of comet Halley, and the core was potato-shaped. Cracks formed in the core of the crust, in which volatile substances were exposed to sunlight and sublimated ice into space. NASA's Deep Space 1 probe flew past the comet on September 22, 2001, approaching 3.417 km.
Comet Wild-2 was discovered by Paul Wild in 1978, but suffered its dramatic changes in 1974. The Swiss calculated that due to the close passage of Jupiter in 1974, the comet (5 km wide) changed its orbit around the Sun. If earlier the path took 43 years, now it is 6 years. Thanks to this, NASA’s mission launched the Stardust probe on January 4, 2004. The probe came so close to the object that it was able to collect particles of coma, and returned safely to Earth. And the samples continue to be considered a valuable source for the study of organic compounds of comets.
NASA's Deep Impact mission reached comet Tempel-1 (8 km / 5 miles wide) on July 4, 2005, and intends to destroy the comet core, creating a cloud of thin material. Only a crater 100 meters wide (328 feet) by 30 meters (98 feet) remained behind. The precious compounds were seen by the Deep Impact spacecraft, and the explosion itself could be observed directly from Earth. In 2011, the updated Stardust-NExT mission visited the comet a second time.
The fifth collision occurred on November 4, 2010 with an enhanced Deep Impact probe from the EPOXI mission with comet Hartley2. The goal was a strange object core, similar to a peanut or chicken drumstick. During a close approach (700 km / 435 miles), photographs of uneven terrain were taken: two coarse blades connected by a smooth center. In some places jets of gas were thrown. Scientists were surprised that the jets are ejected both from the sunlit areas and from the shadowed ones. This data is still being analyzed by researchers.
On February 14, Stardust-NExT visited Comet Tempel 1 for the second time after a 6-year voyage around the Sun. Studies have shown that during travel, the comet was eroded. In addition, the surface of the crater formed after impact was smoother than expected. Therefore, researchers analyze 72 photos to better understand how the comet's nucleus is formed.
On August 6, 2014, the Rosetta spacecraft was in orbit of comet 67P Churyumov-Gerasimenko. After exposure to a weak object gravity, for several days the apparatus made triangular loops for drawing closer. This is the first long-term mission in which a comet is studied from orbit. The apparatus will observe the processes of change on the surface, while it is approaching the sun. In November, a small “Fila” descent vehicle will descend to the surface to drill a comet and collect material. The photo was taken by Rosetta on August 3, when the probe was at a distance of less than 300 km.
