Starship to Zion

I want to read an SF story where you have a small lost colony in a star system somewhere.  They eventually convert en masse to the Restoration.  But its all on paper.  No authority.  They are hopeful that they will be sent an angel someday.  But so far it hasn’t happened.  They struggle with their finite resources to build a broadcaster sending out their complete genealogies so their work can be done.  But even with this hope and this effort, they realize that its still not complete.  Without their genealogies going back beyond the settlement of the colony, which they don’t have, they can receive their individual ordinances and they can be sealed to each other, but they cannot be welded in to the rest of the human race.  They would be an isolated pocket of sealings.

So they decide to launch a starship.  They will send a young man to the stars.  His mission is to marry an LDS girl.