ESA Rosetta Mission: Philae Lander - Game Over!

The first spacecraft ever to land on a comet has fallen silent, entering a potentially long, cold sleep after running out of power.

The European Space Agency's Philae lander completed its last transmission Friday (Nov. 14) at 7:36 p.m. EST (0036 GMT) before settling into a hibernation state as its batteries ran out.

The probe had been studying the surface of Comet 67P/Churyumov–Gerasimenko for 57 hours when it went to sleep, possibly for good.

Philae landed on the comet on Wednesday (Nov. 12) as part of ESA's historic Rosetta mission.

"It has been a huge success, the whole team is delighted," Philae lander manager Stephan Ulamec of DLR German Aerospace Agency, who tracked the comet landing from ESA's Space Operations Center in Darmstadt, Germany, said in an ESA statement.

"Despite the unplanned series of three touchdowns, all of our instruments could be operated and now it's time to see what we've got."

ESA Rosetta mission: Philae lander touches down on Comet 67/P

Philae’s parting image of Rosetta, taken shortly after separation

ESA’s Rosetta mission has soft-landed its Philae probe on a comet, the first time in history that such an extraordinary feat has been achieved.

After a tense wait during the seven-hour descent to the surface of Comet 67P/Churyumov–Gerasimenko, the signal confirming the successful touchdown arrived on Earth at 16:03 GMT (17:03 CET).

The confirmation was relayed via the Rosetta orbiter to Earth and picked up simultaneously by ESA’s ground station in Malargüe, Argentina and NASA’s station in Madrid, Spain.

The signal was immediately confirmed at ESA’s Space Operations Centre, ESOC, in Darmstadt, and DLR’s Lander Control Centre in Cologne, both in Germany.

The first data from the lander’s instruments were transmitted to the Philae Science, Operations and Navigation Centre at France’s CNES space agency in Toulouse.

“Our ambitious Rosetta mission has secured a place in the history books: not only is it the first to rendezvous with and orbit a comet, but it is now also the first to deliver a lander to a comet’s surface,” noted Jean-Jacques Dordain, ESA’s Director General.

“With Rosetta we are opening a door to the origin of planet Earth and fostering a better understanding of our future."

"ESA and its Rosetta mission partners have achieved something extraordinary today.”

“After more than 10 years travelling through space, we’re now making the best ever scientific analysis of one of the oldest remnants of our Solar System,” said Alvaro Giménez, ESA’s Director of Science and Robotic Exploration.

“Decades of preparation have paved the way for today’s success, ensuring that Rosetta continues to be a game-changer in cometary science and space exploration.”

“We are extremely relieved to be safely on the surface of the comet, especially given the extra challenges that we faced with the health of the lander,” said Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Center.

“In the next hours we’ll learn exactly where and how we’ve landed, and we’ll start getting as much science as we can from the surface of this fascinating world.”

Rosetta was launched on 2 March 2004 and travelled 6.4 billion kilometres through the Solar System before arriving at the comet on 6 August 2014.

“Rosetta’s journey has been a continuous operational challenge, requiring an innovative approach, precision and long experience,” said Thomas Reiter, ESA Director of Human Spaceflight and Operations.

“This success is testimony to the outstanding teamwork and the unique knowhow in operating spacecraft acquired at the European Space Agency over the decades.” 

Vintage Comet 67P/Churyumov–Gerasimenko

It was 45 years ago when astronomer Klim Churyumov and Svetlana Gerasimenko, one of his researchers, unwittingly began a new chapter in the history of space exploration.

During a comet-hunting expedition to Alma-Ata Observatory, Kazakhstan, they discovered the bizarre, ice-rich object, subsequently named Comet 67P/Churyumov–Gerasimenko, that is now under close scrutiny by ESA’s Rosetta spacecraft.

In November 2014 it is hoped that more secrets will be revealed when Rosetta’s Philae attempts the first soft-landing on the nucleus of a comet.

These two images, taken with a wide-angle Schmidt telescope, were exposed a short time apart during the historic expedition.

The pair of photographic plates, taken by Klim Churyumov on 21 September 1969, shows a fuzzy object (indicated by the arrows) shifting position slightly in the night sky.

The comet appears indistinct because its solid heart is surrounded by a coma of gas and dust, material that was ejected into space as the ice-rich nucleus was warmed by solar radiation.

Before the era of digital cameras, imaging astronomical objects was a slow, painstaking process involving lengthy exposures of the same part of the sky on glass plates that were coated with a light-sensitive emulsion.

Glass-backed plates, rather than film, were commonly used in astronomy because they did not shrink or deform noticeably in the development process or under different environmental conditions.

They were held in large-format frames for wide-field imaging.

Each successive plate was exposed after an interval of 20–30 minutes.

The plates then had to be taken back to the laboratory to be processed and studied.

By comparing the images, it was possible to find new comets and other fast-moving objects as they shifted across the background of more distant, ‘fixed’ stars.

Since the discovery of this comet, advances in space exploration have revolutionised comet studies, starting with the first close-up images of comet Halley obtained by ESA’s Giotto spacecraft in 1986.

Since then, a handful of comets has been visited by spacecraft and some comet dust has been brought back to Earth.

These studies show that comets can no longer be regarded simply as dirty snowballs. Ideas about their origins and nature have greatly altered and there are still many questions, which Rosetta and its Philae lander could go a long way towards answering.

ESA Rosetta Image: One of Rosetta’s 14m solar wings over Mars Mawrth Vallis region

On 25 February 2007 at 02:15 GMT, ESA Rosetta passed just 250 km from the surface of Mars. 

Rosetta’s Philae lander took this image 4 minutes before closest approach, at a distance of 1000 km. 

It captures one of Rosetta’s 14 m-long solar wings, set against the northern hemisphere of Mars, where details in the Mawrth Vallis region can be seen.

Mawrth Vallis region of Mars is of particular interest to scientists because it contains minerals formed in the presence of water – a discovery made by ESA’s Mars Express.

This image was originally published in 2007 and was taken in black-and-white.

Mawrth Vallis region of Mars

Representative colour was added to the surface of Mars and, in this version, these colours have been slightly enhanced, along with some brightening of details in the solar wing.

On Sunday 2 March, ESA Rosetta celebrates ten years since launch.

The flyby at Mars was one of four planetary gravity assists (the other three were at Earth) needed to boost the spacecraft onto the correct trajectory to meet up with its target, comet 67P/Churyumov–Gerasimenko, in August 2014.

ESA Rosetta will become the first space mission to rendezvous with a comet, the first to attempt a landing, and the first to follow a comet as it swings around the Sun.