In spatial information networks (SIN), communication links are suffered by periodic time-varying channel noise because of the periodic motion orbit of the space nodes and planets. Moveover, SIN communications may have a probability to fail at random times, such as severe rain attenuation on Ka-band downlinks, or solar scintillation during the superior/inferior solar conjunction. In this paper, we propose a time-vary dying channel with finite channel-length and Rician fading to model this SIN channels, and the upper and lower bounds of outage capacity are derived. Furthermore, we propose a sub-optimal distribution rateless coding scheme by using a heuristic method. Simulation results show that, compared with existing LT and Raptor codes, the proposed coding scheme has an outperform improvement of throughput.