WASHINGTON — Sen. Jerry Moran of Kansas likes to think of himself as the space senator — and as the top Republican appropriator for NASA in the Senate, he is set to play a key role in the emerging space race between the United States and China. Beijing has aggressively advanced its space program in recent years, with plans to construct a permanent base on the moon by the end of the decade. China’s ambitions have fueled competition with Washington and spurred a new era of space exploration — one that officials in both countries hope will eventually put humans on Mars. “I would say that we’re in...