International Space Station Extravehicular Activity Results to Date: Summary of Spacewalk Anomalies from Assembly Flight 2A through Expedition 4 U.S. EVA 1

The International Space Station (ISS) program has performed 27 United States (U.S.) led Extravehicular Activities (EVA) from December of 1998 through October of 2001. These spacewalks encompass the initial docking and outfitting of the Unity Node 1 to the Zarya Functional Cargo Block vehicle, through the addition of seven major components to the ISS. This document is an overview of the anomalies associated with the U.S. ISS spacewalks up to the first ISS Expedition Crew U.S. EVA on February 20, 2002. The EVA Group at the Johnson Space Center (JSC) Mission Operations Directorate (MOD) is responsible for planning, training and flight controlling ISS EVAs. The EVA Group also document results for NASA management review. EVA results are presented here by dividing the various anomalies by type. Explanations and lessons learned are provided for anomalies relating to EVA tools, EVA tasks, Spacesuit and Airlock systems and ISS EVA actuated hardware. There have been no anomalies resulting in major impacts to ISS assembly or operations.