U.S. officials appear poised to make history by approving the first private space mission to go beyond Earth's orbit, according to people familiar with the details. The government's endorsement would eliminate the largest regulatory hurdle to plans by Moon Express, a relatively obscure space startup, to land a roughly 20-pound package of scientific hardware on the Moon sometime next year. It also would provide the biggest federal boost yet for unmanned commercial space exploration and, potentially, the first in an array of for-profit ventures throughout the solar system. The expected decision, said the people familiar with the details, is expected...