Design and Testing of an Electronic Extravehicular Mobility Unit (EMU) Cuff Checklist 911529
The Electronic Cuff Checklist (ECC) is an electronic device to be strapped to the wrist of a space suit. The ECC consists of an electroluminescent flat panel display, control and data storage electronics, an RS232 serial data port and a battery. The device is an electronic replacement for the cuff checklist used during the Apollo, Skylab and Shuttle Extravehicular Activities (EVA's). The original cuff checklist consists of up to 25 double sided 7.6 by 17.7 cm (3 inch by 5 inch) pages held open with a spring and mounted on the astronaut's wrist with a device similar to an expandable watch band. The principal advantages of the electronic device are: 1) it can store a larger amount of information than the manual checklist, up to 2000 pages of information with 1 megabyte of memory; and 2) the ECC can be reloaded with new information from an RS232 port on the ground before a shuttle launch or while on orbit such as for Space Station Freedom (SSF) applications. The ECC is located on the astronaut's wrist, which years of experience have demonstrated as an acceptable place to locate the astronaut's information source. The device is autonomous from the rest of the space suit and related life support equipment, thus it can be used by unsuited crew or by crew in a different type of space suit.
The paper will present the results of the design and test of a breadboard version. The breadboard consists of: 1) a commercially available electroluminescent with an active area of 93.5 mm by 74.7 mm and a resolution of 320 pixels by 256 pixels (Cherry Electronics Model EL1D-D000); 2) attached hardware driver on a surface mount circuit board sold with the display; 3) a wire wrap assembled data storage and memory module using an Intel 80C196 microcontroller; 4) an RS232 interface; 5) data handling software and hardware in a PC clone using an Intel 80386 processor; and 6) a laboratory 12 volt power supply. The breadboard was tested in the JSC Building 13 lighting laboratory equipped with a electric arc solar illumination simulator. Testing demonstrated that the display could be read in a wide range of illumination conditions including full sun. A volumetric mockup of the unit was fabricated from a block of plastic encased in a nylon packcloth and Velcro simulation of a thermal cover. Testing in the John Space Center (JSC) Weightless Environment Testing Facilities water tank demonstrated that the cuff checklist could be designed which would not adversely affect the astronaut's reach and mobility.