Science & Environment

Comet 67P presented in silhouette

67P Image copyright ESA/ROSETTA/NAVCAM
Image caption Comet 67P and Rosetta are now just over 400 million km from the Sun, and receding

Perfectly backlit by our star. This is how Comet 67P was pictured this week by the Rosetta spacecraft.

The European Space Agency (Esa) probe was a few hundred km "downstream" of all the vapour and dust being vented from the icy dirt-ball.

Even though the duck-shaped object is heading out of the inner Solar System, it remains classically active.

Rosetta will continue to study the comet until controllers direct it to make a "landing" in September.

Mission officials will endeavour to make this touchdown a gentle one, to ensure data is returned for as long as possible. But it will bring the whole venture to an end.

Rosetta will likely be damaged by the impact and drop all contact with Earth.

In the meantime, scientists hope to gather as much information as they can about the 4km-wide wanderer.

Current observations are telling them about the workings of the tail of material that is carried away from 67P on the solar wind.

This latest image was acquired by Rosetta's navigation camera system. The comet and probe are currently just over 400 million km from the Sun, and receding at 20km per second.

Image copyright ESA/Rosetta/MPS for OSIRIS Team
Image caption The comet comes through the inner Solar System once every 6.5 years

Since its launch in 2004, Rosetta has travelled 7.7 billion km, passing close by Mars and two asteroids on its way out to meet 67P.

The spacecraft arrived at the comet in August 2014, and dropped the Philae robot on its surface in November of that year.

67P's closest approach to the Sun, just inside the orbit of Mars, occurred on 13 August last year.

As the comet and probe now move back out towards the orbit of Jupiter, the amount of power Rosetta can generate from its solar panels will become increasingly limited.

Esa officials see no point in putting the probe to sleep in the hope it could come back to life when lighting conditions improve on 67P's next visit to the inner Solar System.

A more fitting end for the mission, they believe, is to get some spectacular close-up images in a bump-down landing.

Image copyright ESA/Rosetta/MPS for OSIRIS Team
Image caption The Rosetta probe will not survive its September bump-down on the comet

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos