 |  | | | | NASA Glenn's Contributions to the International Space Station
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A new era in space exploration began with the launch of the first element of the international space station. As a primary research and development center for NASA, Glenn played a significant role in the space station's development
Image Right: Image of the International Space Station as the sun rises above the earth. Credit: NASA
Table of Contents
Electrical Power System
Microgravity Science
Missions:
First Element Launch: Zarya
STS-88: The Launch of Unity
STS-92: The Launch of Truss Segment "Z1"
STS-97: The Launch of First US Solar Array
STS-98: The Launch of Destiny, the US Lab Module
STS-100: First GRC Microgravity Payloads
STS-105: More Exposure for Glenn Science on ISS
STS-108: Adding Isolation and Insulation to ISS
STS-110: Space Station Branches Out
STS-111: More Microgravity
STS-112: Station Gets 'Cool' Backbone
STS-113: Endeavour's 'Portentous' Mission
Science Continues Aboard Station
STS-115: The Launch of P3/P4 Truss Segment
Electrical Power System
At the inception of the Space Station Freedom program, NASA Glenn was assigned responsibility for Work Package 4, the complete electrical power system (EPS). Engineers from Glenn's Power and Propulsion Office combined state-of-the-art electrical designs with complex computer-aided analyses to lead the design of the largest power system ever constructed in space. They also developed and tested several critical components and subsystems.
 Image right: Image of Solar array testing in Glenn's Electric Propulsion Laboratory. Credit: NASA
When the space station program was consolidated, this responsibility was transferred to the Johnson Space Center and members of Glenn's design team were an integral part of the process of redesigning the station and transitioning to the existing International Space Station Program. Because of the center's comprehensive background, the Johnson Space Center asked NASA Glenn to oversee and manage the development and testing of EPS flight hardware in preparation for its launch to the space station. This effort included monitoring tests and inspecting hardware at both subcontractor sites where the hardware was manufactured and at the Kennedy Space Center prior to launch.
Glenn's expertise has been used extensively throughout the station power system including switches and converter units. In addition to managing hardware built elsewhere, Glenn manufactured EPS component flight hardware for the station in the form of manually activated switches called circuit isolation devices. Glenn also maintained an engineering support room that was staffed by a team of engineers responsible for monitoring the EPS and making performance predictions during the initial operation of the power system.
Microgravity Science
Glenn has been a frequent contributor to experiments aboard the international space station. Today, NASA Glenn is developing the Fluids and Combustion Facility, a modular, multi-user facility to accommodate microgravity science experiments on board the US Laboratory Module, Destiny. Glenn researchers and partners in industry and academia will continue to define scientific requirements and develop experimental hardware to study combustion processes and fluid physics and to characterize the microgravity environment.
First Element Launch: Zarya
The Russian-built, U.S.-owned Zarya Control Module was launched on a Russian Proton Rocket at 1:40 a.m. EST on Friday, November 20, 1998. NASA Glenn performed extensive analyses of shadowing on the module's solar arrays. The analyses were critical in determining flight modes and operating procedures for Zarya, which means Sunrise in Russian.
STS-88: The Launch of Unity
 On Friday, December 4, 1998 at 3:36 a.m. EST, the U.S. Unity Node was launched aboard the Space Shuttle Endeavor on mission STS-88. The Remote Power Control Modules (RPCM) that are contained in Unity were designed and developed under the lead of NASA Glenn's Power and Propulsion Office.
Image left: Image of Unity and Zarya taken from Space Shuttle Endeavour. Credit: NASA
Each of the twelve small metal containers is filled with circuit breakers. The RPCMs provided switching and protection in case of a short circuit during construction of the ISS as well as during operation of the completed station. They can be controlled by astronauts via laptop computers or from the ground.
STS-92: The Launch of Truss Segment Z1
Integrated Truss Structure (ITS) Z1 is an early exterior framework to allow the first U.S. solar arrays on flight 4A to be temporarily installed on Unity for early power. As the primary payload for STS-92, launched on October 11, 2000, the truss contains a Plasma Contactor Unit that serves as a high-tech grounding rod for ISS. The Hollow Cathode Assembly, which is the major component of the contactor, was designed, developed, built and tested at NASA Glenn. The assembly was later named NASA's 2001 Government Invention of the Year." The truss also contains dc/dc Converter Units (DDCU) to provide grounding and voltage regulation and another set of Remote Power Control Modules (RPCM) like those contained in Unity.
Also, six Circuit Isolation Devices (CID) were delivered to provide the means for a spacewalking astronaut to remove power from selected loads so that power cables can be mated or detached safely. All of this hardware was designed and developed under the lead of NASA Glenn's Power and Propulsion Office.
STS-97: The Launch of First US Solar Array
 Image left: Image of ISS showing the deployed arrays. Credit: NASA
Integrated Truss Structure P6 is the official designation for the hardware launched on STS-97, station assembly flight 4A, on November 30, 2000. This hardware comprises the first U.S. photovoltaic (PV) module, including solar arrays, batteries and other power system electronics. It was deployed on that mission and is currently supplying the station with power. Glenn has had a significant role in the design and development of the PV module and managing the hardware development for it, including testing, system analysis and participating in the neutral buoyancy testing of the assembly operations. Also installed on that mission were two radiators that remove waste heat from the module. One of these radiator panels was tested in the Space Power Facility, the world's largest space environment simulation chamber at Glenn's Plum Brook Station in Sandusky, OH.
A third spacewalk was added to the mission to install the Glenn-developed Floating Potential Probe to measure the plasma field surrounding the space station. It helped to determine the effectiveness of the Plasma Contactor Units. Engineers at Glenn monitored the performance of the station's electrical power system and the probe from our Engineering Support Room. Glenn's efforts were being managed by the Power and Propulsion Office.
STS-98: The Launch of Destiny: US Lab Module
Destiny is the U.S. Laboratory Module. It is the centerpiece of the International Space Station, where unprecedented science experiments are performed in microgravity. It will eventually be home to Glenn's Fluids and Combustion Facility (FCF). Destiny was the primary payload for STS-98, which launched on Feb. 7, 2001.
Destiny uses dc/dc Converter Units (DDCUs) to provide grounding and voltage regulation and another set of Remote Power Control Modules (RPCM's) like those contained in Unity. These components were designed and developed under the lead of NASA Glenn's Power and Propulsion Office.
STS-100: The First GRC Microgravity Payloads
Characterizing the microgravity environment of the international space station is critical to understanding the science results. NASA Glenn provided two units that were delivered by the space shuttle Endeavour after it lifted off from the Kennedy Space Center on April 19, 2001 to begin the STS-100 mission. These units supported microgravity science research onboard the international space station. The Space Acceleration Measurement System-II (SAMS-II), powered up in early June 2001, measured accelerations caused by vehicle, crew and equipment disturbances. To complement the SAMS-II measurements, the Microgravity Acceleration Measurement System (MAMS), powered up in early May 2001, recorded accelerations caused by the aerodynamic drag created as the space station moved through space. It also measured accelerations created as the vehicle rotated and vented water. The data was transmitted from the station to Glenn's Telescience Support Center and was available to researchers during the mission via the web.
 Image right: Image of EXPPCS data. Credit: NASA
Endeavour also delivered the first station-bound microgravity science experiment from NASA Glenn. The Experiment of Physics of Colloids in Space (EXPPCS) investigation was activated on May 31, 2001 and began gathering data on the basic physical properties of colloids (a system of fine particles suspended in a fluid) by studying three different colloid sample types. After being inactive during the STS-105 crew change over, the EXPPCS experiments resumed during the first week of September. Experiment operations, which concluded in February 2002 were a resounding success. Each of the eight sample cells worked well and produced interesting and important results. In virtually all cases, the principal investigator learned new and exciting things that have significantly enhanced our understanding of the science under investigation. The potential payoffs of EXPPCS include improvements in the properties of colloidal suspensions used in everyday life -- ceramics, paints, food products, drug delivery agents -- as well as advances in colloid engineering that may yield an entirely new class of materials, photonic band gap crystals, which can affect the properties of light passing through them. Such photonic crystals may find uses as optical switches, filters, and lasers for advanced telecommunication networks and displays.
STS-105: More Exposure for Glenn Science on ISS
 Image left: Image of MISSE experiment tray. Credit: NASA
The Space Shuttle Discovery lifted off on Aug. 10, 2001 with several science payloads from Glenn. Many materials samples were provided by Glenn's Electro-Physics Branch for the first externally mounted experiments conducted on the ISS. The Materials International Space Station Experiments (MISSE) Project is an endeavor to fly materials and other types of space exposure experiments on the space station. The experiments are installed on Passive Experiment Carriers mounted to the station's airlock. One of Glenn's experiment named PEACE (Polymer Erosion And Contamination Experiment) Polymers included 41 samples that were exposed to atomic oxygen and solar radiation for four years and returned to the project team for analysis. Another 45 samples from Glenn studied the effects of exposure to the space environment on optical, mechanical and shielding properties.
STS-108: Adding Isolation and Insulation to ISS
Space Shuttle Endeavour lifted off on December 5, 2001 to begin the STS-108 mission. Making the one-way trip to the ISS were two additional Glenn-developed Circuit Isolation Devices (CIDs). The CIDs were stowed on-orbit on the exterior of the ISS and installed in the "S0" Truss when it was delivered to ISS on STS-110 early in 2002. The CIDs permit control of power flow to the "S0" (starboard) truss. CIDs 7 and 8 join six other CIDs, which have been on-orbit since October 2000. CIDs 1-6 are being used to channel power to the Lab module, Destiny, and to exterior mounted spare hardware. Also during STS-108, the mechanisms that turn the large US solar arrays, known as the Beta Gimbal Assemblies (BGAs), had thermal blankets installed on them as a result of concerns associated with induced thermal stresses. Since it is important to have the arrays face the sun to generate power, Glenn analysts used their space station power analysis code, SPACE, to determine the power generation capability for numerous scenarios. Their results helped the mission planners prepare for the spacewalk to install the blankets on the BGAs.
 Image right: Carl Walz during STS-79. Credit: NASA
The primary objective of the STS-108 mission was the transport of the fourth crew to the space station. That crew included Ohio astronaut and Cleveland native Carl Walz. A veteran of three space flights, Walz was a Mission Specialist aboard STS-79, the fourth Shuttle/Mir docking mission. Walz performed flight tests of the station hardware, conducted internal and external maintenance tasks, and developed the capability of the station to support the addition of science experiments.
STS-110: Space Station Branches Out
The Space Shuttle Atlantis lifted off on April 8, 2002 with a structural component that enabled the international space station to branch out. The main objective of the STS-110 mission was to deliver and install Truss Segment S0 and the Mobile Transporter (MT). Glenn led the design and development of several electrical power system components that are installed on the truss: large automated switch boxes called Main Bus Switching Units (MBSUs), dc/dc Converter Units (DDCUs) to provide voltage conversion, regulation and isolation, and Remote Power Control Modules (RPCM's) like those already contained in several nodes and truss elements. Two additional Glenn-developed Circuit Isolation Devices (CIDs) were stowed on-orbit on the exterior of the ISS during STS-108 and installed on the "S0" Truss during the mission. The CIDs permit control of power flow to the "S0" (starboard) truss. CIDs 7 and 8 joined six other CIDs, which have been on-orbit since October 2000.
STS-111: More Microgravity
The STS-111 mission of Space Shuttle Endeavor began with a launch on June 5, 2002. Glenn-developed hardware for InSPACE (Investigating the Structure of Paramagnetic Aggregates of Colloidal Emulsions). InSPACE was designed to obtain fundamental data of the complex properties of magnetorheological fluids, a new class of smart materials capable of providing rapid rheological response that can be used to advance such items as brake systems, seat suspensions, robotics, clutches, airplane landing gear and damper systems.
 Image left: Astronaut Carl Walz works in the Destiny laboratory module. Credit: NASA
Also onboard were additional sensors and control unit hard drives for SAMS (Space Acceleration Measurement System), a system to detect and report data on vibrations onboard the space station. Remote Triaxial Sensor (RTS) systems were deployed near the payloads requiring direct measurements of the acceleration environment. A controller, initially consisting of a space station-derived laptop, tied the independent RTS systems together on orbit and provided a single-point communication link to the SAMS-II Ground Operations Equipment located in Glenn's Telescience Support Center, where data were received for distribution to users via the web.
Research for InSPACE was conducted by the Expedition 6 crew in the Microgravity Science Glovebox (MSG) that was also delivered on STS-111. The MSG was installed in the Destiny laboratory module to support numerous investigations in multiple disciplines including Glenn's research on fluids physics and combustion science. The glovebox was designed to contain experiments with fluids, flames, particles and fumes. In an Earth-based laboratory, liquids stay in beakers or test tubes. In the near-weightlessness of the station, they could float away from the work area and could get into the cabin air and irritate a crew member's skin or eyes or even make them sick. Uncontrolled liquids could damage the station's sensitive computer and electrical systems or contaminate other experiments. Glenn's Microgravity Science Division has experience with approximately 30 glovebox investigations on the Shuttle and the Russian Mir space station.
STS-112: Station Gets 'Cool' Backbone
The Space Shuttle Atlantis began its journey to the International Space Station on October 7, 2002. The STS-112 mission set the stage for the outward expansion of the International Space Station with the delivery of the first starboard truss segment, the S1 Truss. It was attached to the Central truss segment, the S0 Truss. It includes a radiator that is part of the station's central thermal control (cooling) system. The S1 truss also contains dc/dc Converter Units (DDCUs) to provide grounding and voltage regulation and another set of Remote Power Control Modules (RPCM's). Engineers at Glenn designed these electrical power system components and are still active in the management of the hardware.
The ISS radiator system maintains the temperatures of systems and components. Unlike the radiator of a car, which actually relies on forced convection, a space radiator truly radiates excess heat to the cold blackness of space from its large surface area. Similar to a car's radiator, a working fluid absorbs the heat through a distributed plumbing systems and dumps it into the radiator's panels. The radiator panels were folded to reduce the size during launch. They were extended after the S1 truss was fully mated to the station. Testing of the radiator was performed by the Glenn Research Center at the Space Power Facility located at its Plum Brook Station in Sandusky, Ohio. This facility is the world's largest space environment simulation chamber (100 feet in diameter by 122 feet in height) and is used to ground-test large space-bound hardware. Additional cooling radiators also were delivered.
STS-113: Endeavour's Portentous Mission
The Space Shuttle Endeavour began its journey to the International Space Station on November 23, 2002. In addition to exchanging the Expedition 5 and 6 crews, the STS-113 mission continued the outward expansion of the space station with the delivery of the first port-side truss segment, the P1 Truss. It was attached to the Central truss segment, the S0 Truss. It included a radiator that was part of the station's central thermal control (cooling) system. The P1 truss also contained dc/dc Converter Units (DDCUs) to provide grounding and voltage regulation and another set of Remote Power Control Modules (RPCM's). Engineers at Glenn designed these electrical power system components and are still active in the management of the hardware.
Glenn's Microgravity Research activities were also expanded during Expedition 6. Investigations began using the Glenn-developed hardware for InSPACE (Investigating the Structure of Paramagnetic Aggregates of Colloidal Emulsions) that was delivered during the STS-111 mission in June 2002. Another Glenn experiment that was delivered during STS-113 was the Coarsening of Solid-Liquid Mixtures 2. The materials science space flight experiment, designed to investigate the kinetics of competitive particle growth within a liquid matrix, was delayed until subsequent expeditions. Both experiments were designed to be conducted in the Microgravity Science Glovebox in the Destiny Laboratory.
Science Continues Aboard Station
 Image right: Lighter tin particles float on the solid-liquid mixture in normal earth gravity (left), while the low gravity environment of space (right) eliminates effects such as buoyancy, allowing for better understanding of particle growth and size distribution. Credit: NASA
During the investigation of the space shuttle Columbia accident and preparations for the shuttle's return to flight, the crews of the International Space Station continued to conduct science investigations. The Microgravity Science Glovebox served as the host for several experiments from Glenn. The Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions (InSPACE) experiment was the first to be conducted in the repaired MSG during Expedition 6. Managed by Glenn, InSPACE studied how particles respond to a pulsed magnetic field in a microgravity environment. The remaining baseline test runs were completed during Expedition 7. Another Glenn experiment, Coarsening of Solid-Liquid Mixtures 2, completed successful on-orbit engineering verification operations during Expedition 7.
The Binary Colloidal Alloy Test-3 (BCAT-3) was delivered via a Russian Progress in January 2004. Operations began in March with experiments conducted by astronaut Michael Foale, Expedition 8 commander and NASA ISS science officer. Colloids are systems of fine particles suspended in a fluid. They are found in a variety materials, such as aerosols, foams, paints, cosmetics, milk and biological cells. Colloids are technologically interesting because they are the right size to manipulate light. More useful photonic crystals can be built from two different types of building blocks mixed together, yielding a binary alloy. Astronauts homogenize the samples before attaching the Slow Growth Sample Module to the Maintenance Work Area (MWA) table set up in the Destiny laboratory of the ISS. They take photographs to document crystal formation or phase separation in the colloidal samples over several months. Experiments continued in Expedition 9 with astronaut Mike Fincke, in Expedition 10 with astronaut Leroy Chaio, and during Expedition 12 with astronaut William McArthur.
 Image left: Astronaut Michael Foale photographs sample for the BCAT-3 experiment. Credit: NASA
STS-115: The Launch of the P3/P4 Truss Segment
NASA resumes construction of the International Space Station during the space shuttle mission designated STS-115. Astronauts are installing a girder-like structure, known as the P3/P4 truss segment that will double the station's power capability. The 35,000-pound segment is comprised mainly of solar cell arrays, batteries and power conditioning equipment. These were developed under the management of NASA's Glenn Research Center, Cleveland.
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