The European Space Agency’s (ESA) Rosetta mission has concluded with an emotional comet landing, bringing to an end a hugely successful mission to comet 67P/Churyumov-Gerasimenko.
Rosetta successfully touched down on the comet at about 6.18am EDT (11.18am BST) today, descending at walking pace while snapping images and performing science all the way down.
Confirmation arrived 40 minutes later in the form of an abrupt loss of signal, with scientists at ESA’s mission control in Darmstadt, Germany hugging as the mission was officially declared over.
“This is it,” said Patrick Martin, Rosetta Mission Manager, immediately following the landing. “I can announce the full success of this historic descent of Rosetta to 67P, and I declare hereby the mission operations ended for Rosetta."
Now on the surface, it is no longer able to point its antenna to Earth, meaning we will never hear from the spacecraft again. It was also commanded to switch all its systems off immediately following the landing. But its two-year mission at Comet 67P has been hugely fruitful, furthering our understanding of these icy rocks in the Solar System like never before.
“It’s been a very unbelievable mission,” said ESA Director General Jan Woerner, speaking prior to the landing via ESA's live stream of the event.
Rosetta had a large potential area on the comet where it might land, but the team managed to touch down just 40 meters (130 feet) from their original target. That was in a region of the comet called Ma’at, on the smaller lobe of the comet.
This location was picked for its exciting features, namely a number of active pits more than 100 meters (330 feet) wide and 50 meters (165 feet) deep, that may be firing jets of dust into space. The region also included “goosebumps”, small meter-sized bumps that indicate how the comet grew into its current shape, when two previous comets collided and joined together.
But despite the somber landing, with a tense mood in mission control prior to the loss of signal, the mission is not over. There are still reams of scientific data for the team to go through, with mission scientist Matt Taylor saying there would be decades of scientific research still to come from Rosetta.
Mission controllers hugged as the loss of signal was confirmed. ESA
How Rosetta's mission came to an end. ESA
The mission has already proved hugely fruitful. Among its discoveries, Rosetta has found oxygen in the gas cloud around the comet, discovered the ingredients for life, and also found that Earth’s water may not have been delivered by comets. It also stayed in orbit around the comet as it reached its closest point to the Sun, observing the dramatic changes as the comet heated up.
There have been 672 scientific papers written about Rosetta’s data so far, with more than 50 in the pipeline.
The decision was made to end the mission in this manner because the comet’s six-year orbit around the Sun is taking the spacecraft out to the orbit of Jupiter. This will significantly reduce the amount of solar power available to Rosetta, making communications and operations difficult. Thus, the decision was made to bring the mission to a controlled end, rather than fighting to look after an aging spacecraft.
Rosetta launched on March 2, 2004 from the Guiana Space Centre in French Guiana atop an Ariane 5 rocket. The spacecraft then began a 10-year journey to Comet 67P, spending most of it in hibernation, with its solar panels the sole provider of its power.
The journey saw Rosetta travel 6 billion kilometers (3.7 billion miles) and included a flyby of Mars and three flybys of Earth to reach the comet. In June 2015, the spacecraft woke up from hibernation, before officially entering orbit on August 6, 2014. What followed were two years of scientific observations, including the dramatic release and landing of its Philae probe in November 2014.
Philae bounced across the surface before coming to a rest, completing more than 80 percent of its science. Now, Rosetta has joined it on the same lobe of the comet, although being on the other side, there was no chance of them being in sight of each other.
Rosetta snapped this image, with its landing site on the smaller lobe seen. ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Unlike Philae, which had a bit of a bumpy landing, Rosetta’s speed was so slow (about walking pace) that it was expected to come to rest on the surface without bouncing up again, although we'll never know for sure. There was a small chance Rosetta would actually end up in one of the pits, as the possible landing site was across quite a large area, although this didn’t come to be.
The mood at the finale was bittersweet, with the mission given a fitting send-off, but bringing to an end what has been a globally acclaimed mission for ESA. Now, they will look to upcoming missions to Mars, Mercury, and Jupiter’s icy moons to generate the same level of excitement.
But for now, it’s goodbye to Rosetta, the most successful comet mission in history. It's one that has told us more about our beginning in the Solar System than ever before.
“Farewell Rosetta, you have done the job,” said Martin.
