Development of a Heads-Up Display for Extravehicular Activities

Abstract

Spacesuits represent a significant burden on the wearer in terms of isolation and lack of dexterity. Compared to the current population, never out of reach of a smart phone for access to myriad data bases, the spacesuited astronaut is currently limited to their knowledge, training, and verbal guidance from mission control. These capabilities will be increasingly ineffective in future space exploration missions, where time delays or lack of line-of-sight to Earth will effectively eliminate mission control as a factor, and neither knowledge or training will be wholly adequate to support the crew through many hundreds of hours of EVA on an extended mission to the moon or Mars. To address this problem, the University of Maryland has been performing a multi-year investigation of options to enhance data presentation to spacesuited crew, through the development of helmet-mounted non-obstructive visual overlays. Initial efforts focused on the provision of head-mounted displays for one or both eyes, remotely controllable to pivot up onto the forehead when not in use. This proved cumbersome, and two current efforts are proceeding in parallel. In the first, an oversized helmet was developed for a UMd MX-D spacesuit simulator which allows the wearing of a Microsoft HoloLens inside the helmet. This allows the presentation of a high-resolution visual overlay which does not obstruct the actual visual field, but the HoloLens has a very small field of view. The parallel effort is focused on a helmet specifically designed to incorporate an internal projector and optics to provide an overlay on an external visor assembly, which can be raised or lowered as desired. Details of both systems are presented, along with results from both laboratory and initial field testing. The paper includes lessons learned and plans for further development activities.