So, as we all know to complete the book we need all calcified fragments. we have just over 2 months to do so. BUT! as we also know, the game's RNG is a total sleeze bucket, and the last 4 fragments I need are all CHALLENGE SPECIFICS. and not common ones either... I need (XLIV), (XLV), (XLVIII), and (XLIX). So, tell me bungie. What are the odds of the required challenge modes to be the weeklies that we need? on that note, for the sake of us all, do we REALLY have to wait an entire WEEK? Given the games habit of repetitious replays, is 2 months even enough time to allow the missions to cycle around?