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Aerospace Frontiers
Glenn Guides Electrical Requirements for Successful Mission
On June 22, Glenn invited the public to the Visitor Center Auditorium to view the Space Shuttle Atlantis land after completing a 14-day journey of more than 5.8 million miles in space. During the mission, the STS–117 crew successfully completed construction to increase the power capability of the International Space Station.
Image right: Astronauts Patrick Forrester (right) and Steven Swanson, both STS-117 mission specialists, participate in the mission's fourth and final extravehicular activity (EVA). Among other tasks, they continued activation of the station's new starboard 3 and 4 (S3/S4) truss segment.
As the only research laboratory orbiting the Earth, the station is a work in progress, with constantly changing amounts and kinds of electrical power supply and demand. These challenging tasks rely on expert advice from a team at Glenn called the System Power Analysis for Capability Evaluation (SPACE) Team.
SPACE also is the name of the software code developed by the team that predicts the maximum power level that the space station power system can sustain throughout a variety of conditions. The code was developed in the late 1980s to support the design of the precursor to the station, Space Station Freedom. Since then, dozens of engineers have contributed to its enhancement, which includes mathematical models of the solar arrays, batteries and power management and distribution equipment. Utilizing this code, the SPACE Team provides analyses that are required to certify space shuttle flight readiness.
The most pressing challenge addressed by the team involved the STS-117 mission, during which a fifth and sixth set of solar arrays and batteries, or power channels, had to be installed on station. These new power channels on truss segments S3/S4 became a part of station's electric power system designed under Glenn's guidance in the 1990s. The S3/S4 added to station's 11-segment integrated truss structure (station's backbone) will provide one-fourth of the total power generation for the completed space station.
Of the four channels that were already on the station, three were active and one temporarily not in use, or dormant. The two new power channels added during STS-117 required retracting a second solar array for the channels to track the sun. Additionally, two of the active channels had to constantly send power to the dormant channels to prevent them from freezing or getting too hot.
Glenn's SPACE Team advised NASA's Johnson Space Center that the dormant channels temporarily receive less power, and the loads normally shared among two power channels, be fed by the more capable power channel.
"We started our analysis with a flight plan that had some flexibility, and worked to determine options that would give operators the best path forward," said SPACE Team Technical Lead Tony Jannette. "During the flight, we saw that many of our recommendations were implemented. We are pleased that our analysis played a role in a successful mission."
The team also assessed the station's electric power system performance for joint operations when Atlantis docked with station. That included launch, power channel startup and deployment of solar arrays.
Later this year, the SPACE Team plans to continue its involvement with space electric power needs with the first docking of the European Space Agency's Automated Transfer Vehicle to the space station.
For more on the STS-117 mission, visit http://www.nasa.gov/shuttle
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By Katherine K. Martin
On June 22, Glenn invited the public to the Visitor Center Auditorium to view the Space Shuttle Atlantis land after completing a 14-day journey of more than 5.8 million miles in space. During the mission, the STS–117 crew successfully completed construction to increase the power capability of the International Space Station.
Image right: Astronauts Patrick Forrester (right) and Steven Swanson, both STS-117 mission specialists, participate in the mission's fourth and final extravehicular activity (EVA). Among other tasks, they continued activation of the station's new starboard 3 and 4 (S3/S4) truss segment.As the only research laboratory orbiting the Earth, the station is a work in progress, with constantly changing amounts and kinds of electrical power supply and demand. These challenging tasks rely on expert advice from a team at Glenn called the System Power Analysis for Capability Evaluation (SPACE) Team.
SPACE also is the name of the software code developed by the team that predicts the maximum power level that the space station power system can sustain throughout a variety of conditions. The code was developed in the late 1980s to support the design of the precursor to the station, Space Station Freedom. Since then, dozens of engineers have contributed to its enhancement, which includes mathematical models of the solar arrays, batteries and power management and distribution equipment. Utilizing this code, the SPACE Team provides analyses that are required to certify space shuttle flight readiness.
The most pressing challenge addressed by the team involved the STS-117 mission, during which a fifth and sixth set of solar arrays and batteries, or power channels, had to be installed on station. These new power channels on truss segments S3/S4 became a part of station's electric power system designed under Glenn's guidance in the 1990s. The S3/S4 added to station's 11-segment integrated truss structure (station's backbone) will provide one-fourth of the total power generation for the completed space station.
Of the four channels that were already on the station, three were active and one temporarily not in use, or dormant. The two new power channels added during STS-117 required retracting a second solar array for the channels to track the sun. Additionally, two of the active channels had to constantly send power to the dormant channels to prevent them from freezing or getting too hot.
Glenn's SPACE Team advised NASA's Johnson Space Center that the dormant channels temporarily receive less power, and the loads normally shared among two power channels, be fed by the more capable power channel.
"We started our analysis with a flight plan that had some flexibility, and worked to determine options that would give operators the best path forward," said SPACE Team Technical Lead Tony Jannette. "During the flight, we saw that many of our recommendations were implemented. We are pleased that our analysis played a role in a successful mission."
The team also assessed the station's electric power system performance for joint operations when Atlantis docked with station. That included launch, power channel startup and deployment of solar arrays.
Later this year, the SPACE Team plans to continue its involvement with space electric power needs with the first docking of the European Space Agency's Automated Transfer Vehicle to the space station.
For more on the STS-117 mission, visit http://www.nasa.gov/shuttle
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