Extravehicular Activity Development of Unforeseen International Space Station Maintenance

Date

2016-07-10

Journal Title

Journal ISSN

Volume Title

Publisher

46th International Conference on Environmental Systems

Abstract

Extravehicular activities (EVAs)—or spacewalks—are never routine. EVA Operations on the International Space Station (ISS) have and still are adapting to a new culture sans the Space Shuttle. Training astronauts for spacewalks has taken on a different philosophy; how to fix broken hardware during an EVA can become an innovative advancement. The ISS is aging, resulting in unforeseen hardware failures. The ISS Program is also having to repair or maintain hardware that was not designed to be EVA compatible. One of these necessary repairs occurred on US EVA 30 in February 2015. The EVA crew members were tasked with the challenge to repair the Latching End Effector (LEE) on the Space Station Remote Manipulator System (SSRMS) (i.e., robotic arm). The SSRMS LEE had been showing increased motor current when driving latches, indicating possible grinding in the hardware. Losing this capability would be a tremendous hit to the ISS Program, including the inability to capture certain visiting vehicle resupply missions. This LEE hardware was not designed to be EVA compatible. In the end, the project evolved into an innovative advancement. This paper discusses the planning process, or “Road to EVA,” for the repairs of the SSRMS LEE. Designers and engineers needed to determine the root cause of the failure and what could be done to fix it. The flight operations team got involved to determine whether the repairs could be executed during an EVA, and then the team needed to develop the procedures to execute. Practice runs in Houston’s Neutral Buoyancy Laboratory were essential to develop these procedures. Once solid procedures were developed, the astronauts who would be executing the EVA needed to be trained. The majority of this training needed to occur on orbit, as they were already in space when the final plan was determined. Many lessonswerelearnedfrom theRoadtoEVAthatcanbeofinsighttofutureengineersandEVArepairmissionplanners.

Description

United States
SGT
403
ICES403: Extravehicular Activity: Operations
Vienna, Austria
Sarah Kazukiewicz Korona, Stinger Ghaffarian Technologies, NASA Johnson Space Center
The 46th International Conference on Environmental Systems was held in Vienna, Austria, USA on 10 July 2016 through 14 July 2016.

Keywords

EVA operations, EVA Training, EVA Development, EVA Execution, EVA Procedures, EVA Planning

Citation