Despite rough landing, comet mission sends data

Europe Space Agency’s robot lab Philae, which ran into some trouble when its harpoons failed to deploy on landing, is working well on the surface of the 67P comet, though it is likely to have perched on a steep slope, ground controllers said on Thursday.

Philae's anchoring harpoons failed to deploy during its seven-hour descent from the mothership Rosetta, but it still managed to send back scientific data for the European Space Agency’s (ESA) flagship mission as well as the first-ever picture taken from the surface of a comet, which was beamed half-a-billion kilometres back to Earth on Thursday.

“Philae is working well. Its battery is working well and is providing power,” mission head Philippe Gaudon of France’s space agency CNES told AFP over the phone from ground control in Toulouse .

But photos from the robot lab had sent suggested that “it is likely to have landed on a steep slope”. A tweet in the name of Multi-Purpose Sensor (MUPUS), onboard the Philae, said: “Magnetic analysis reveals 3 landings at 15:33, 17:26 & 17:33 GMT.”

This means the washing machine-sized probe may have touched down three times on the low-gravity comet, which is zipping towards the Sun at 18 kilometres per second, according to updates from ground control.

“Short status update: we believe that Philae bounced (possibly 3 times) but sits safely on the comet now,” said another tweet at 08:00 GMT. Equipped with 10 instruments, Philae is designed to carry out an array of experiments on Comet 67P or Churyumov-Gerasimenko. It is the highlight of a massively complicated 1.3-billion-euro project that took more than two decades. Rosetta was hoisted into space in 2004, and took more than a decade to reach its target in August this year, having used the gravitational pull of Earth and Mars as slingshots to build up speed.

The pair covered 6.5 billion kilometres together before Wednesday’s separation and Philae's 20-kilometre descent. Scientists hope that samples drilled out from the comet by Philae will unlock details about how the planets – and possibly even life evolved.

Comets date back to the formation of the solar system some 4.6 billion years ago and some scientists suspect impacting comets delivered water to early earth.

Philae was designed to touch down at a gentle 3.5 km per hour, then fire two harpoons into a surface, which engineers hoped would provide sufficient grip while the robot conducts its experiments. The harpoons, however, failed to deploy.

Envisaged tests include drilling through the comet surface and analysing the samples for chemical signatures. Philae was designed to operate for about 60 hours on a stored battery charge, but several months more with a sunlight boost.

The lander complements 11 instruments aboard Rosetta, a three-tonne orbiter responsible for four-fifths of the expected scientific haul from its vantage point in orbit. Whatever happens to Philae, Rosetta will continue to escort the comet as it loops around the Sun. On August 13, 2015, the “67P” comet will come within 186 million kilometres of the star.

The mission is scheduled to end in December 2015, when the comet heads out of the inner Solar System.