London: For the first time in history, a spacecraft has landed on a comet. According to scientists, the momentous event represents the culmination of over 28 years of research on comets.
“The seeds for this mission took root during the 1986 visit of Halley’s Comet,” said professor Akiva Bar-Nun of Tel Aviv University’s department of geosciences who is working for the European Space Agency (ESA) that is behind the feat.
“The ESA’s Giotto spacecraft passed by Halley but remained more than 600 miles away from it. So a group of us got together to design a spacecraft that would not pass by a comet – but would instead fly with the comet and bring samples of its ice back to earth,” informed professor Bar-Nun.
“When we proposed to ESA to bring a sample back, they said, ‘You have no idea what the mechanical strength of the ice is. How are you going to drill into it?'” professor Bar-Nun continued.
So researchers shifted the emphasis to what is now known as Rosetta – a spacecraft that could match the orbit and speed of the comet, staying with the comet for a year and a half and launch its probe at the appropriate time.
On Nov 12, the ESA’s Rosetta spacecraft released its lander Philae towards Comet 67P/Churyumov-Gerasimenko, roughly the size of central London some 316 million miles from Earth.
The descent took approximately seven hours, with a signal confirming touchdown received at Earth.
Comets stayed cold for 4.5 billion years – the age of the solar system – and now one is coming right at us, heated by the sun, spewing gasses, dust, and ice particles.
“Mixed into this dust is a plethora of organic material that may have been brought to our planet by a comet and where, dissolved in the ocean, it prepared the scenario for the emergence of life on Earth,” he maintained.
The Rosetta mission is scheduled to last until December 2015, four months after the comet has made its closest approach to the sun and started to head back out to the more distant reaches of the solar system.
The Philae lander could survive for up to three months, but its lifetime depends on whether it will be able to effectively recharge its batteries – and whether it can hang on tight as it swings through the solar system.
PIC: Seeds of comet landing sown 28 years ago