The required conditions for igniting and maintaining the lattice-assisted nuclear reactions are different. The required conditions are strict for the ignition, and looser for maintaining the reaction. The ignited reaction is stable and remains active for a very long period of time. These observations indicate that the experimental conditions in the deuterium-palladium electrochemical system meet the requirements for sustaining the reaction, and the so-called reproducibility problem arising from the uncertainty of ignition of the process. It is hypothesized that muon catalyzed fusion ignites the reaction, which then becomes self-sustained. The random nature of the cosmic ray produced muons is consistent with the observed reproducibility problem. Cosmic ray muons, collimated by electric, and/or magnetic fields, might be the right tool to reliably ignite the LANR process. The optimum energy and flux density of muons, which can activate the fusion, could be experimentally defined. Planetary and astrophysical aspects of the proposed hypothesis are briefly discussed.