Rigidizable Inflatable Get-Away-Special Experiment (RIGEX) - 07.29.14
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Rigidizable Inflatable Get-Away-Special Experiment (RIGEX) operates in the Space Shuttle Cargo Bay and is designed to test and collect data on inflated and rigid structures in space. Inflatable tubes will be heated and cooled to form structurally stiff tubes.
Science Results for Everyone
United States Department of Defense Space Test Program, Johnson Space Center, Houston, TX, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Department of Defense (DoD) - Retired
ISS Expedition Duration
October 2007 - April 2008
Previous ISS Missions
- Three inflatable tubes will be heated and cooled to form a structurally stiff material.
- The primary objective for RIGEX is to test and collect data on space rigidized structures. The data collected will be compared to laboratory data from tests performed on Earth.
- RIGEX is a self-contained, automated experiment that will be located in the Space Shuttle's cargo bay.
RIGEX is a self-sufficient computer and sensor system that will test and collect data on rigidized structures. The rigidized structures that are used for this investigation are three tubes, which will go from a soft structure to a stiff or rigid structure. The primary objective for RIGEX is to verify and validate data that has been collected during tests on Earth.
RIGEX will operate in the US Department of Defense's (DoD) Canister for All Payload Ejections (CAPE). CAPE will be located on the cargo bay sidewall in the Space Shuttle. RIGEX consists of three tubes that are contained in an aluminum structure; a computer will be used for control and data collection; and a heating and inflation system that uses nitrogen gas.
Once the Shuttle is in orbit, the crew will be responsible for powering up the computer and the heaters. After this initial task, the computer will run the experiment. To begin the experiment, the tubes are inflated. Inflation involves heating the tubes above 120 degrees C and inflating with nitrogen gas. During this time, the gas pressure and vibrations are measured. After cooling, the gas is vented so the tube has the same pressure inside and out. Still photographs will be taken during and after inflation of the RIGEX tubes. The inflation process is repeated for all three tubes.
Another key part to this experiment involves exciting the tubes. The technology that is used to provide the excitation is the Macro Fiber Composite (MFC) patch, developed by NASA's Langley Research Center. MFC provides a vibration source using a linear up-chirp wave form, meaning that the waveform will increase in frequency from 0Hz to 1000Hz. The vibration testing will measure the structural characteristics of the tubes after inflation. The measurements will be used to determine the transfer function of the tubes; this will be accomplished by using a program on the computer that is located in the CAPE.
Inflatable structures can be used for antennas, communication satellites, trusses for manned space station, and support structures for solar sails. It will also provide a light-weight, compact, and cost reducing option for future spacecraft missions.
This technology can lead to an increase in communication satellites that provide television, telephone and communication services.
Three tubes that are contained in an aluminum housing structure will be heated, inflated and cooled. ThermoFoilTM sensors will measure the temperature of the ovens during the heating phase and a triaxial accelerometer will measure the vibrations that the tubes experience after excitation. The tubes and the computer, which is internal to the RIGEX hardware, containing the data will be returned to the principle investigator for analysis and comparison to the ground data following the Shuttle flight. It will take approximately 20 minutes for one member of the crew to perform the activation and deactivation activities.
The Space Shuttle crew will power up the computer that is used to run this experiment. Once the computer is operational, the tubes, one at a time, will be heated then inflated. The tubes will be allowed to cool, forming the structurally stiff material. The tubes will then be excited by using vibrations in order to collect data on the modal response.
Ground Based Results Publications
Ruggiero E, Park G, Inman D. Smart Materials in Inflatable Structure Applications. 43rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, Denver, CO; 2002
Gunn-Golkin A, Helms S, Cobb R. Structural Verification of the Rigidizable Inflatable Get-Away-Special Experiment. 20th Annual AIAA/USU Small Satellite Conference, Logan, UT; 2006
Moody DC, Raines RA, Cobb R, Palazotto AN. The Design and Analysis of a Space-Based Experiment for Inflatable Structures. Transactions of the AOC; 2004 106-134.
Lindemuth SN, Slater JC, Cobb R, Maddux MR. Development and Test of a Rigidizable Inflatable Structure Experiment. 45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Palm Springs, CA; 2004
The image above shows folded rigidizable inflatable tubes. Image courtesy of NASA, Johnson Space Center.
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These images show a laboratory demonstration of RIGEX. The image on the left shows a tube prior to inflation whereas the image on the right shows the tube post inflation. Image courtesy of NASA, Johnson Space Center.
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