"The adventure continues," the ESA declared.
"ESA's Science Programme Committee has given formal approval to continue the mission for an additional nine months."
In a final flourish, the spacecraft Rosetta may be "landed" on 67P/Churyumov-Gerasimenko, the comet it has been shadowing, the agency said.
In doing so, the mothership would rejoin the tiny lab it has nurtured in an odyssey spanning billions of kilometres.
Launched in 2004, the mission has been applauded as a milestone in space exploration.
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It comprises an orbiter, Rosetta, carrying a robot lab, Philae, which seek to unveil the secrets of comets -- primordial clusters of ice and dust that may shed light on the formation of the Solar System and on how life developed on Earth.
In November, Philae was landed on the comet surface, and in a dramatic 60-hour episode carried out a range of experiments before its stored battery power gave out.
But the plucky 100-kilo lander has now revived, thanks to sunlight bathing its solar panels as the comet hurtles towards the Sun.
Both Rosetta and Philae will have a grandstand view when 67P reaches perihelion, its closest point to the Sun, on August 13, scientists hope.
The comet will then loop back into deep space, beginning another six-and-a-half-year trek around our star.
"We'll be able to monitor the decline in the comet's activity as we move away from the Sun again, and we'll have the opportunity to fly closer to the comet to continue collecting more unique data.
"By comparing detailed 'before and after' data, well have a much better understanding of how comets evolve during their lifetimes."
The mission had been nominally funded until the end of December 2015, and its extension was not a surprise.