Recently changes in culture and technology have led to new options. A late 20th century alternative is an ecological burial. This is a sequence of deep-freezing, pulverisation by vibration, freeze-drying, removing metals, and burying the resulting powder, which has 30% of the body mass. Alternatively, a green burial is not a new process, but a very old one involving burying the unpreserved remains in a wood coffin or casket, which will naturally decompose, and thus not permanently take up land. A very different option from that is a space burial, which uses a rocket to launch the cremated remains of a body into orbit. This has been done at least 150 times. However, most of these remains are not complete, nor launched permanently into space, due to cost. Two partial permanent space burials are those of astronomer Eugene Shoemaker, a part of whose remains were launched to the moon, and Clyde Tombaugh, the astronomer who discovered Pluto, part of whose remains travel with the New Horizons spacecraft, which has/will leave the solar system. Other remains have been launched only into earth orbit, and either recovered, or left to be lost.