We perform reliability modeling of a high-altitude module of a tethered telecommunication platform as a heterogeneous k-out-of-n system. Several variants of such a model are considered, including the ones, taking into account the dependence of system failures on the configuration of the failed components, and taking into account the redistribution of load between the remaining workable components. An algorithm has been developed that allows to calculate the reliability function of such a system, the average value and variance of its uptime, and the quantiles of the uptime distribution function.