A computer generated image of space probe Rosetta. Europe’s ground-breaking quest to unravel the Solar System’s mysteries concludes Friday with the Rosetta comet chaser crashlanding onto the cosmic wanderer’s rocky surface. If you know nothing about Rosetta's adventures, here is a breakdown through numbers:
1: Rosetta became the first spacecraft, in August 2014, to enter the orbit of a comet. In November of that year, it sent down robot lab Philae, which became the first comet lander.
6.5 billion: Kilometres (four billion miles) travelled from Rosetta’s launch in March 2004 until it reached Comet 67P/Churyumov-Gerasimenko, aided by gravity boosts on Earth and Mars flybys. By now, the accumulated distance is 7.9 billion km.
12 years, six months, 28 days: Mission duration from launch to end.
786 days: Rosetta spent circling 67P, sniffing and tasting its atmosphere and photographing it from all angles.
19 kilometres (11 miles): the altitude from which Rosetta was set on a collision course with the comet.
14 hours: the duration of Rosetta’s freefall.
90 centimetres (35 inches) per second: the speed at which Rosetta is to make a “controlled impact” with the comet.
720 million kilometres (450 million miles): Rosetta’s distance from Earth when it received its suicide command.
14.2 kilometres (8.7 miles) per second: the speed of the comet, with Rosetta and Philae on deck, zipping around our Sun on a near seven-year elongated orbit.
40 minutes: the time it took for signals to travel between mission control in Darmstadt and Rosetta.
11: Science instruments onboard Rosetta, added to another 10 on Philae.
100 kilograms (220 pounds): Washing machine-sized Philae’s weight on Earth, compared to one gram (0.04 ounces) on the low-gravity comet. Rosetta weighs some three tonnes.
1.4 billion euros ($1.5 billion): the cost of the mission, approved in 1993.
500: Number of scientists and engineers involved in the project.