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As a result of recommendation from the Augustine Panel, the direction for Human Space Flight has been altered from the original plan referred to as Constellation. NASA's Human Exploration Framework Team (HEFT) proposes the use of a Shuttle Derived Heavy Lift Launch Vehicle (SDLV) and an Orion derived spacecraft (salvaged from Constellation) to support a new flexible direction for space exploration. The SDLV must be developed within an environment of a constrained budget and a preferred fast development schedule. Thus, it has been proposed to utilize existing assets from the Shuttle Program to speed development at a lower cost. These existing assets should not only include structures such as external tanks or solid rockets, but also the Flight Software which has traditionally been a “long pole” in new development efforts. The avionics and software for the Space Shuttle was primarily developed in the 70's and considered state of the art for that time.

The purpose of the Space Shuttle Cockpit Avionics Upgrade project (1999 – 2004) was to reduce crew workload and improve situational awareness. The upgrade was to augment the Shuttle avionics system with new hardware and software. A major success of this project was the validation of the hardware architecture and software design. This was significant because the project incorporated new technology and approaches for the development of human rated space software. An early version of this system was tested at the Johnson Space Center for one month by teams of astronauts. The results were positive, but NASA eventually cancelled the project towards the end of the development cycle. The goal to reduce crew workload and improve situational awareness resulted in the need for high performance Central Processing Units (CPUs). The choice of CPU selected was the PowerPC family, which is a reduced instruction set computer (RISC) known for its high performance.

There has been an assembly complete maintenance concept of operations associated with International Space Station (ISS) since the earliest design stages. However, ISS has been and will be at an intermediate stage of completion for several more years, requiring an interim solution to conduct maintenance. The ISS Program's logistics and maintenance plan dictates which spare components are on-orbit already and the order in which new ones will launch. This information dictates what Extravehicular Activity (EVA) maintenance capabilities are expected, which then has to be reconciled with the support equipment available that enables EVA to perform those tasks safely and effectively. The interim solution described is characterized by use of those ISS EVA components and methods that have proven efficient and useful during the ISS assembly EVA's performed to date.

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.

An overview of the proposed operational methods for performing Extravehicular Activity (EVA) maintenance for the International Space Station (ISS) is provided. External maintenance of ISS will be required during assembly and will continue for at least ten years after assembly is complete. It is likely that the operational methodology for performing maintenance will evolve as more on-orbit ISS EVA experience is gained. However, an initial operational plan is necessary for timeline and tool development. Initial operational concepts outlining assumptions regarding how EVA operations will be conducted during maintenance of ISS after assembly complete are provided. These maintenance scenarios are designed to reduce overhead wherever possible in order to make the EVA operations more efficient. Also presented is a summation of orbital replacement unit (ORU) information as it pertains to the operational concept.

Water is an important commodity during spaceflight. The Shuttle-Orbiter produces water on-orbit as a direct result of electricity generation. Hydrogen/oxygen fuel cells provide ample water for drinking, food rehydration and hygiene purposes. During the Shuttle-Mir program, water was transferred between the orbiter and the Mir space station to provide crewmembers with drinking water and water to be used for electrolysis for oxygen production. Due to the incompatibility of Russian and U.S. drinking water biocides (silver versus iodine), methods and hardware were developed to remove iodine and allow for the addition of silver biocide and minerals. At the completion of the Mir program, 5,800 kilograms of water had been transferred from the Orbiter to Mir. A refined version of the hardware used during the Mir program is now under flight development and certification for operations on board the International Space Station (ISS).

A software application has been developed for analysis of the International Space Station Thermal Control System for mission operations. This software serves needs unique to spacecraft mission control. Characteristics include multiple vehicle configurations, multiple equipment rack heat loads, complex fluid-loop heat transfer, and integral orbit propagation for radiator performance prediction at any attitude. Object-oriented programming using a C++ class library provides an integrated, interdisciplinary model. Model runtimes are on the order of one minute per day of mission time. Outputs are selected plots, electronic files, and vector displays. Performance and accuracy are verified by comparison with engineering models.