The High Energy Laser End-to-End Operational Simulation (HELEEOS) has been developed by the Air Force Institute of Technology's Center for Directed Energy (CDE). HELEEOS is a fast running Matlab-based model. HELEEOS is available as an executable with a Windows install program.

HELEEOS is anchored to respected wave optics codes and all significant degradation effects, including thermal blooming and optical turbulence, are represented in the model. Furthermore, the model incorporates realistic total system weight constraints. Currently HELEEOS offers both scaling relationships developed at AFIT as well as use of the Scaling for HEL and Relay Engagement (SHaRE) scaling laws. SHaRE provides detailed modeling of multiple relay mirrors and adaptive optics performance, crucial for many scenarios. Key features of HELEEOS include climatological, seasonal, diurnal, and geographical spatial-temporal variability in molecular and aerosol absorption and scattering profiles and optical turbulence strength, and a methodology to estimate the level of uncertainty in the calculated probability of kill (Pk). Probability of kill, required dwell time, and effective range as functions of engagement parameters such as range, aperture diameter, and dwell time, are used as typical evaluation metrics.

HELEEOS has been recently expanded to model atmospheric effects pertinent to directed energy scenarios for wavelengths between 0.4 µm and 8.6 m.