The journey has been a long one; Rosetta started its pursuit of the comet back in 2004. You know what they say about perseverance — apparently, that’s the way to catch a comet. Since then, it’s traveled over six billion kilometers, circled the sun five times, and gotten three essential gravity boosts to put it on the right orbital path. So, are we there yet? Not quite. Rosetta has fewer than 300 miles to go, and on August 6, the long wait will be over. Among other things, that means space enthusiasts have only two more days to enter the “are we there yet?” competition.
Comet 67P/Churyumov–Gerasimenko takes 6.5 years to orbit the sun, swinging out as far as Jupiter and as near as between Mars and Earth’s orbits. Catching up to the comet is difficult — not only does Rosetta have to be on the right orbit, but it has to be going the right speed. The comet moves at about 55,000 kilometers per hour, so ESA engineers have tried to match that speed, and since May have been carefully slowing Rosetta down a bit so it will be in relative lock-step with the comet, rather than simply flying by it.
On August 6, Rosetta will be fewer than 100 kilometers away, and will start a series of three triangular arcs around the comet. It could get as close as 10 kilometers during these maneuvers. All the while, Rosetta’s instruments will gather information about the comet, including the gasses that compromise the fuzzy coma and how they impact the spacecraft, as well as the behavioral changes of the comet as it nears the sun. In November, Rosetta will send its Philae lander down to the comet’s surface for a closer look.
For now, there seems to be just one burning question:
— ESA Operations (@esaoperations) August 4, 2014
Long answer: lots and lots of math. Short answer: yes. Surprisingly, an astronaut could, at least theoretically, jump from the spacecraft onto the comet. Any volunteers?