Location

Howard Johnson Plaza-Hotel, Atlantis/ Discovery Rooms

Start Date

26-4-1995 2:00 PM

End Date

26-4-1995 5:00 PM

Description

One of the main purposes of International Space Station Alpha (ISSA) is to provide a premier microgravity environment for science, technology, and research. To accomplish this, the design requirements for ISSA address the two different categories of quasi-steady-state accelerations and vibratory accelerations, specifying not-to-exceed microgravity levels for frequencies ranging from 0.01 to 300 Hertz (Hz). The basic requirements have remained unchanged since Space Station Freedom days. However, the capability to meet the requirements in the 0.1 to 300 Hz range has long been at issue because many station components, including the crew members themselves, cause high frequency disturbances that exceed allowable microgravity levels.

To meet the design requirements, a new multiprong approach has been developed for the ISSA that includes minimizing disturbances at the source when feasible, a new Active Rack Isolation System, and risk mitigation plans for all identified risk areas. When possible, microgravity disturbers (e.g., pumps, rotating joints) are being attenuated so that the rest of the station does not feel their effects. However, this solution is impractical in many cases (for example, it's not easy to isolate the crew from the rest of the station!), so the Active Rack Isolation System that is being developed will isolate the payload from the disturbers rather than the other way around. The system will be flown as a flight experiment in 1996. This new development, along with the innovative team process that has been put in place, provides an efficient and cost effective approach to ensure that the ISSA is a world-class microgravity facility.

Comments

The Evolution of ISSA

Session Chairman: William Bates, Chief of Staff for Space Station Program Office, NASA, Johnson Space Center

Session Organizer: Terri Cardone

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Apr 26th, 2:00 PM Apr 26th, 5:00 PM

Paper Session II-A - International Space Station Alpha Microgravity Environment

Howard Johnson Plaza-Hotel, Atlantis/ Discovery Rooms

One of the main purposes of International Space Station Alpha (ISSA) is to provide a premier microgravity environment for science, technology, and research. To accomplish this, the design requirements for ISSA address the two different categories of quasi-steady-state accelerations and vibratory accelerations, specifying not-to-exceed microgravity levels for frequencies ranging from 0.01 to 300 Hertz (Hz). The basic requirements have remained unchanged since Space Station Freedom days. However, the capability to meet the requirements in the 0.1 to 300 Hz range has long been at issue because many station components, including the crew members themselves, cause high frequency disturbances that exceed allowable microgravity levels.

To meet the design requirements, a new multiprong approach has been developed for the ISSA that includes minimizing disturbances at the source when feasible, a new Active Rack Isolation System, and risk mitigation plans for all identified risk areas. When possible, microgravity disturbers (e.g., pumps, rotating joints) are being attenuated so that the rest of the station does not feel their effects. However, this solution is impractical in many cases (for example, it's not easy to isolate the crew from the rest of the station!), so the Active Rack Isolation System that is being developed will isolate the payload from the disturbers rather than the other way around. The system will be flown as a flight experiment in 1996. This new development, along with the innovative team process that has been put in place, provides an efficient and cost effective approach to ensure that the ISSA is a world-class microgravity facility.

 

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