Pioneer 10's last message

After more than 30 years in space heading away from Earth, Pioneer 10 has sent its last signal home.

Pioneer's last, very weak signal was received on 22 January, after which US space agency (Nasa) engineers reported that its power source had decayed such that it might not be capable of sending another message.

Following its encounter with Jupiter, Pioneer 10 explored the outer regions of the Solar System, studying the solar wind as well as cosmic rays from deep space. Since its official science mission ended on 31 March, 1997, Pioneer's weak signal has been tracked by Nasa's Deep Space Network as part of a new study of communication technology in support of a future Interstellar Probe mission.

At last contact, Pioneer 10 was 12.2 billion km from Earth, or 82 times the normal distance between the Sun and the Earth.

Read more at http://news.bbc.co.uk/1/hi/sci/tech/2802041.stm.