Comet in closeup: Rosetta spacecraft sends back incredible pictures on approach to Comet 67P/Churyumov-Gerasimenko
The European Space Agency's Rosetta spacecraft is now very close to its target, Comet 67P/Churyumov-Gerasimenko - only one day away, in fact, from when it will begin a complex set of maneuvers that will place it into orbit around this 'dirty snowball', in preparation for putting a lander down onto the comet's complex surface.
The above image is a composite of four separate images of the comet, captured by Rosetta's NAVCAM as the spacecraft drew closer and closer over the past several days. The images reveal not only the tumbling rotation of this 'contact binary' comet, but also the complex features - ridges, crevasses and even impact craters - that are spread across its surface.
Starting on August 6, when Rosetta reaches a distance of 100 kilometres from the comet, the spacecraft will begin flying in a triangular pattern, spiraling in over the next month or so, on its final approach to orbit around the comet. There, it will map out its surface in detail and then moving in even closer to release the Philae lander, which will move in to touch down on the comet sometime in November. The ESA animation below shows how they'll accomplish all of this and gives the team's schedule prior to the lander phase of the mission.
Rosetta's journey to Comet 67P/Churyumov-Gerasimenko has taken over a decade, from its March 2004 launch, and the spacecraft will stay with the comet through until December 2015. In that time, 67P/Churyumov-Gerasimenko will swing closer to the Sun, crossing inside the orbit of Mars between June and November of next year, before heading back out to just beyond the orbit of Jupiter. Since the comet will sprout a coma and tail sometime soon, as light and radiation from the Sun heats it up, Rosetta will be able to watch this process as it happens, mapping out the growth of both in the coming months, and then how they diminish after the comet gets far enough away from the Sun late next year.
The data the ESA gathers from all of this will go a long way to helping us better understand these icy bodies, and 67P/Churyumov-Gerasimenko will give us a specific look at these short-duration comets, which spend most of their life in or near the inner solar system. By comparison, Comet Halley - probably the most famous comet we know of - has an orbit that extends far out, beyond Neptune, and Comet C/2013 A1 Siding Spring, which will make a close flyby of Mars in a few months is making its very first pass through the inner solar system (as far as we know), and may have an orbit that measures in the millions of years. The comparison of these comets should provide us with some incredible insights.
For the ESA's great "Meet a Comet" infographic, click here, and if you'd like to track Rosetta's journey so far, and see the path the spacecraft and comet duo will take in the months to come, the ESA has a great interactive simulation on their website (click the image below).
The ESA will also be broadcasting the rendezvous live over the web, starting at 4 am EDT, Wednesday, August 6. The live feed can be seen on their website (click here).