ESA's Rosetta orbiter is preparing to make a daring 6 km (3.7 miles) pass of one of Comet 67P/Churyumov–Gerasimenko's most active regions – an area on the comet's larger lobe designated as Imhotep. As the comet moves closer to the Sun, mission controllers are expecting to see an exponential increase in volatile activity, and ESA hopes that the new orbits planned for the little probe will allow scientists to gain a better understanding of these effects.
With Philae having passed into that long night, and with little prospect of a revival, the Rosetta mothership is the European Space Agency's last remaining asset within close proximity of the comet. Her closest pass to 67P will take place at 12:41 GMT on February 14th with the Sun directly behind the probe presenting mission controllers with optimum conditions for studying the dust particles layering the surface of the comet's nucleus. The pass will allow Rosetta to focus on areas exhibiting high levels of outgassing, and grant scientists an opportunity to better understand the relationship between the increase in activity and the comet's coma, the nebulous envelope around its nucleus
"The upcoming close flyby will allow unique scientific observations, providing us with high-resolution measurements of the surface over a range of wavelengths and giving us the opportunity to sample – taste or sniff – the very innermost parts of the comet’s atmosphere," says Matt Taylor, project scientist for ESA's Rosetta project.
Following the orbiter's close brush with 67P, Rosetta will set about a new series of flybys at heights varying between 15 and 100 km (nine and 62 miles), allowing each of Rosetta's eleven scientific instruments to operate at their optimum distance, thus maximizing the scientific output of the maneuvers. The probe's closest approach to the Sun, known as the perihelion, will take place on August 13th, taking the comet as close as 186 million km (116 million miles) from the fiery giant, and bringing comet activity to a crescendo.
"We’re in the main science phase of the mission now, so throughout the year we’ll be continuing with high-resolution mapping of the comet," says Taylor. "We’ll sample the gas, dust and plasma from a range of distances as the comet’s activity increases and then subsides again later in the year."
Following the maneuvers, mission operators will decide the next move for Rosetta, and attempt to determine just how much longer the historic little explorer will continue to operate.
The following video courtesy of ESA outlines Rosetta's maneuvers leading up to, and after, the February 14th 6 km pass.