Portable Equipment Panel Development for Modular Power Architectures

Modular systems are inherently inefficient with respect to their function, as their composition is limited to discrete modules of a fixed size. These modules carry a certain amount of overhead (such as packaging) that further stray from a mass- or volume-optimal design. However, the long-term benefits of a modular system greatly outweigh the ese short-term costs. Commonality, flexibility, scalability, interoperability, supportability, and availability are all attributes that give modular systems the advantage in mission-critical applications. Therefore, it is prudent to select a modular architecture for deep-space power systems. The Portable Equipment Panel (PEP) was developed to address the need for a universal voltage adapter for low-voltage portable equipment. Currently on this ISS, each piece of equipment has its own, bulky "watermelon" voltage adapters, which are specific to that piece of equipment. The function of the PEP removes the need to develop and qualify different voltage adapters by providing the appropriate voltage to the equipment automatically when the connector is mated. PEP prototypes were successfully tested, and the concept was slated to be installed on the Orion vehicle, but funding cuts prevented further development. The Advanced Exploration Systems (AES) Modular Power Systems (AMPS) project is developing standards to describe modular space power system architectures and components. To determine reasonable requirements for these standards, prototype power distribution components were developed, including point-of-load switchgear, bus switchgear, housekeeping, bi-directional DC/DC converter, and controller (data/networking) modules. The addition of a module with the functions of a PEP would greatly enhance the fidelity of the standard and improve its efficacy. The goal is to develop and demonstrate functions of the PEP in a modular form factor, compatible with the AMPS [draft] standard.

The current state-of-the-art portable equipment panel (PEP) is a brass-board prototype developed for the Constellation Program's Orion spacecraft. The purpose of the Orion PEP was to power various portable equipment without the need for individual power adapters. Using a combination of analog and digital controls, the Orion PEP converted the nominally 120-Volt DC spacecraft bus into a voltage level from 3-volts to 27-volts, automatically selected by the load. Before the Constellation program had been canceled, there were plans to build three flight PEP units for the Orion crew cabin, with the potential to build additional flight units for the ISS and Altair as well. The Orion PEP brass-board prototype would be enhanced through the proposed development of a design and prototype that meets the AMPS Modular Power Standard. In meeting the Modular Power Standard, the PEP prototype would enable future human exploration mission architectures, which will rely on modular power systems as they cannot carry sufficient spares of individual components for long-duration missions. Additionally, the PEP design inherently eliminates the need for a multitude of power converters to service portable loads, thus reducing the overall weight and stored volume of the electrical power system. The proposed PEP development has the opportunity to immediately impact current NASA missions under development in HEOMD, including the Deep Space Gateway and the Deep Space Transport. It also has the potential to enable new future NASA missions, as it could be used as a mobile power source for ascent/descent vehicles, surface habitats and rovers for human surface missions. Commercially, the modular PEP design may also be of interest to space tourism companies, enabling their customers to charge their portable devices while in space. If the intended result of developing a modular PEP prototype is not achieved, lessons learned from the development effort could be used to improve the Modular Power Standards, thus improving their adoptability and flexibility to support multiple modular power system architectures.