The Rosetta spacecraft is nearing the end of its historic, 12-year comet chase, slowly falling towards the surface of the dusty, icy body in a mission that has provided insight into the early days of the solar system and captured the public’s imagination.
The spacecraft has stalked comet 67P/Churyumov–Gerasimenko across more than 6 billion km (3.7 billion miles) of space, collecting a treasure trove of information on comets that will keep scientists busy for the next decade.
On Friday morning, the European Space Agency said the “collision manoeuvre” started last night was on track and the point of no return had been reached, putting Rosetta on course to crash into the comet at 1138 British time. Confirmation will be received on Earth about 40 minutes later.
“We want to go out at the peak of capability. We don’t want a comeback tour that’s rubbish. We will end in a very rock-and-roll fashion,” project scientist Matt Taylor said ahead of the final descent.
Rosetta’s instruments and camera are currently relaying back data and images, giving scientists insight into the structure of the comet before the spacecraft is permanently shut down.
The descent will reveal information on the side walls of the comet, crucial to understanding how comets formed, plus on large 100-metre (109-yard) wide pits, which scientists believe are key to how the comet releases gas and dust as it is warmed by the sun.
The mission has managed several historic firsts, such as getting a spacecraft into orbit around a comet and the unprecedented landing of a probe on the surface of a comet. A handful of previous spacecraft snapped pictures and collected data as they flew past their targets.
Daniel Brown, an astronomy expert at Nottingham Trent University, said the images sent back from the Rosetta mission were “as powerful as Neil Armstrong’s first steps on the Moon”.
Data collected by Rosetta and lander Philae, which reached the surface in November 2014, is already helping scientists better understand how the Earth and other planets formed.
For example, scientists now believe that asteroids, not comets were primarily responsible for delivering water to Earth and other planets in the inner solar system, possibly setting the stage for life.
“We’ve just scratched the surface of the science. We’re ending the mission, but the science will continue for many years,” Taylor said.
Rosetta will free-fall into the comet at the speed of a sedate walk, but it is not designed to withstand the impact.
The European Space Agency is ending the mission because 67P is racing toward the outer solar system, out of range for the solar-powered spacecraft.
Rosetta also has been subjected to the harsh radiation and extreme temperatures of space since launching in March 2004 and is unlikely to last too much longer