City on a Hill and Sojourner — Michael J. Findley

Persecution of believers in Christ is already happening. Many of the details of City on a Hill are not Science Fiction but current events. One day soon the only refuge for the faithful may be space. Follow the founding of the once-godly Space Empire through its degeneration in Sojourner, where a desperate couple fights loneliness and equipment malfunction to pioneer piloting a gas-collecting balloon ship to the outer planets. Their rebellion against the corrupt government opens the outer reaches of the Solar System to exploration.