A group of US researchers has proposed sending a large nuclear powered spacecraft to explore Neptune and its largest moon, Triton. The Neptune orbiter (pictured) would carry two atmospheric probes to investigate the planet and a lander to drop onto the surface of Triton. The sheer size of the 36-metric ton spacecraft would require it be launched in two parts and joined in orbit. The mission to Neptune would cost an estimated $3-4 billion dollars and take 30 years from beginning to end. To date only one spacecraft, Voyager 2, has flown by the planet (1989). Read more at BBC News(1).