To put things in perspective, the comet, 67P/Churyumov-Gerasimenko, is about 4km in diameter, moving at 135,000kms per hour. Rosetta's rendezvousing with the comet required travelling a cumulative distance of over 6.4 billion kms. Gravity assists were needed from four planetary flybys – one of Mars (2007) and three of Earth (2005, 2007 and 2009) – a long circuitous trip that took ten years to complete.
Now back to my Javascript callback bugs