On Friday 12 November last year the lander Philae, deployed by the robotic probe Rosetta, successfully landed on the 67P/Churyumov–Gerasimenko comet.

The comet is a chunk of rock and ice approximately four kilometres wide (tall, across, around). It travels about 135,000 kilometres per hour, millions of miles away. So think about that for a moment - the European Space Agency sent a probe across space with a 100 kilogram lander and after ten years of flight, it successfully landed its payload on a comet orbiting the sun at a rate of 38 kilometres per second.

Next time your kid says something about never having to use trigonometry ever in their lives, get them to find out about the Rosetta Mission. That's maths in action right there, folks. 

It wasn't quite a fairy-tale story though. Due to the unpredictable surface of the comet, the washing-machine-sized Philae didn't land perfectly and bounced a few times; finally landing in a less than ideal spot. You see, Philae is a solar powered lander, a fare mirror-ball of reflectors to capture all that good light from our star the Sun. Trouble is, that ungraceful, bouncy landing saw wee Philae in a place that didn't get any sunlight and by the next day, it was running out of juice.

Philae did manage to send back images and data about the comet before going into hibernation - or 'safe mode' - as they called it. No one could tell when or if the lander would ever get enough light to recharge the batteries. The experts hoped that one day it would; that the comet's rotation might bring light to the darkness; until then though, it was snooze-town for the plucky little lander.

And then it happened. 212 days since Philae's last message, there was enough sunlight to recharge the lander's batteries and it sent a message to Earth: Philae woke up!

Associated links

• Rosetta (spacecraft) (Wikipedia)
• Philae (lander) (Wikipedia)
• @philae2014 (Twitter)
• @ESA_Rosetta (Twitter)
• European Space Agency (website)
• Philae probe: Rosetta scientists says lander's material is 'amazingly exciting' (The Guardian)
• Now That The Philae Comet Lander Is Awake, What Happens Next? (io9.com)
• Rosetta Live Blog (ESA)