Longliner

Due to some inspired computer hacking, young Joh trains himself to operate the Longliner.
Young Joh is then sent off to run an ancient Empire trade route. The knowledge learned, as a result of the Longliner voyage will greatly advance the science of Xerbuc. The voyage of the Longliner will require some 2,000 Xerbuc years. However, due to the compression of time for someone traveling near the speed of light, the voyage will require only about 18 years of young Joh's life.
Young Joh is willing to serve what amounts to 18 years in solitary confinement, because only young Joh sees what he will gain from his 18 years of solitary confinement.