The Rosetta mission has been studying the 67P/Churyumov-Gerasimenko for more than a year now and the spacecraft will be accompanying the comet as it makes its closest approach to the sun on Aug. 13.
The comet is on a 6.5-year journey around the sun, and Rosetta joined it when 67P/Churyumov-Gerasimenko was 336 million miles from the center of the solar system. Traveling at about 75,000 miles per hour, the spacecraft and the comet are due to arrive at their orbit's closest point at 116 million miles from the sun by Aug. 13.
A comet's closest approach to the sun is an event called perihelion. Matt Taylor, a Rosetta project scientist from the European Space Agency (ESA), said that the event is an important milestone for any comet, but 67P/Churyumov-Gerasimenko's will be particularly noteworthy because it will be the first time that a comet will be getting its closest to the sun with a spacecraft in tow.
Activity on the comet has been growing since Rosetta met up with it due to an increase in exposure to solar energy. 67P/Churyumov-Gerasimenko has been warming up for once, resulting in more of its frozen ices evaporating, which has led to a fuzzier atmosphere around the comet. Scientists expect the sublimation of frozen ices to peak between August and September, and have pointed out the possibility of outbursts, although these are unpredictable.
Other comets reaching perihelion have been destroyed for getting too close to the sun, but the 67P/Churyumov-Gerasimenko will not be flying that near so it is in no danger. In fact, the comet's closest approach is still farther than the distance between the planet Earth and the sun.
The comet has also completed many of its previous orbits without trouble because it is not classified as a "sungrazer," unlike Comet C/2012 S1 ISON, which broke apart when it reached perihelion in November 2013. Although not of the same classification, 67P/Churyumov-Gerasimenko does have a fracture 1,640 feet in length that scientists will be observing closely when the comet peaks in activity in August and September.
67P/Churyumov-Gerasimenko last achieved perihelion on Feb. 28, 2009. After the event on Aug. 13, the comet will continue on its orbit, moving away from the sun to head back to the solar system's outer reaches. During perihelion, Rosetta will be operating from a safe distance away from the comet to ensure the spacecraft's safety.
