Early concepts right|thumb|250px|ROMBUS concept art Before the second half of the twentieth century, very little research was conducted into space travel. During the 1960s, some of the first concept designs for this kind of craft began to emerge.
early concepts right|thumb|250px|rombus concept art before the second half of the twentieth century very little research was conducted into space travel during the 1960s some of the first concept designs for this kind of craft began to emerge