Completed Projects
Software Development
Probabilistic Analysis of ISS Electrical Power System Techanical Details
In the example International Space Station (ISS) problem, the Electrical Power System (EPS) consists of the solar arrays, the batteries, the Battery Charge-Discharge Unit (BCDU), the DC Switching Unit, and a setof DC-to-DC Conversion Units (DDCU) connected as shown in the diagram. The entire system was modeled using a NASA-developed code specific to the ISS electrical power system called SPACE. A 5-element set of input uncertainties was assigned that included one environmental variable (Earth albedo). Since the efficiencies of the BCDU and the DDCU’s are a function of power level, the entire curves for these variables were handled as a single uncertainty. N&R Engineering coupled the NASA SPACE code to its own SUA code to perform the probabilistic analysis.
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The results showed a mean power level (per panel) of 13.72 kwe with a 0.138 kwe standard deviation, although the power could vary between 13.2 and 14.2 kwe. The DDCU efficiency and the spacecraft attiude error are the most important uncertainties. This information helps mission operators plan the power allocation more effectively.
Contacts
N&R Engineering:
Dr. Vinod Nagpal
440-845-7020
Client (NASA): TBD
