Human enhancement is one of the hotspots in the field of ethics of science and technology, but scholars focus almost only on conventional enhancement on the earth. Changing sight from ground to outer space, we will discover a new research subfield of human enhancement: human enhancement in outer space, which is by no means a false proposition, and certain enhancements appear to be necessary for successful outer space missions. However, the human enhancement in outer space will cause many ethical issues, including not only the existing problems of delimitation between treatment and enhancement, but also such newly emergent problems as the reshaping of human values concept and the construction of moral system, which may significantly affect man's moral intuition, ethical rules, and the formulation of public policies, and may even strike man's value system. Human enhancement in outer space is an issue full of unknown challenges. Researchers are expected to brainstorm for guiding human enhancement in space from theory to practice and from planning to exercising, and helping the steady development of aerospace industry.