FARNBOROUGH, England—Senior Chinese and European space officials have been discussing potentially wide-ranging cooperation on manned exploration programs, a prospect that threatens to further complicate the future of the international space station.

Jean-Jacques Dordain, director-general of the European Space Agency, said in an interview that the two sides have talked about the issue of extensive in-orbit cooperation in some detail, without coming to any resolution. His comments, made during an international air show here,...