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ISS and Kibo

A Modal Survey Test of "Kibo" conducted

PM Qualification Model
Engineering Model of the Manipulator
A Modal Survey Test was conducted on the Pressurized Module (PM) and the Manipulator of "Kibo", the Japanese Experiment Module (Kibo), at Tsukuba Space Center from May 28 to June 4, 1999.

What is a Modal Survey Test?
A Modal Survey Test is conducted to determine the vibration frequency at which the object tested begins to resonate.

Test Objective
Kibo will be launched by three Space Shuttle flights. During a launch, the Shuttle vibrates vigorously, which causes Kibo to vibrate in the same manner. Kibo's vibration is fed back to the Shuttle. If this vibration is large, it could affect the attitude of the Shuttle.

To avoid excessive vibration, all cargo in the Shuttle payloadbay is assigned a range of safe vibration. Using computer simulation to analyze a mathematical vibration model of each piece of cargo, NASA confirms that cargo vibration will not affect the Shuttle launch safety.

The PM and the Manipulator are combined in a launch configuration and subjected to vibration to obtain vibration data. The data is compared with the data simulated by the vibration model that was set up during the design phase of Kibo. The Modal Test is conducted to confirm that any differences between the two sets of data stay within an acceptable range.

Test Method
The test was conducted using the Qualification Model of the PM and the Engineering Model of the Manipulator.

The PM with the attached Manipulator is first installed on the simulated support structure, which fixes the cargo in the payloadbay of the Shuttle. Data is then collected from over 400 acceleration sensors, attached to the PM and the Manipulator while applying vibration from zero to 100 Hz randomly, with a force of 15kgrms. Also, a simulation of this test is performed using the vibration model that was set up during the design phase of Kibo. The results of this simulation and the data obtained by this Modal Test are compared. If the differences between them exceed the predetermined limits, the vibration model will have to be modified so that the differences fall in the acceptable range. It will take about half a year to evaluate the test results and modify the model.
The completed vibration model will be submitted to NASA. NASA will apply this model in the Shuttle and payload launch configuration vibration tests and confirm the launch safety.

Feature of the test configurationManipulator (front) and PM (back).Acceleration sensorVibrator

Comments from NASDA' s key person

Kaoru Miyake
JEM project Team
Space Environment Utilization System Department
National Space Development Agency of Japan



From the Space Station Test Facility to the Spacecraft Integration and Test Building.
Securing the test area was the toughest thing I had to do. At Tsukuba Space Center, Kibo is not the only item being developed. Satellites are being developed and tested, and other technology developments are under way. Negotiations with other sections to secure the test area are the major activities. When the test area is finally acquired, it is time to start test preparations. Experiment racks will be installed inside PM. The racks are simulated by dummy racks which simulate the weights and centers of gravity for the launch configuration.

Transporting Kibo, which weighs a total of 15 tons, is the next problem. It takes about four hours pulling by a forklift truck to move it from the Space Station Test Facility to the Spacecraft Integration and Test Building, several hundred meters away. From the entrance of the Spacecraft Integration and Test Building to the test area, we move Kibo manually using ten people. We next set it on Air-skates, which expel compressed air to float their loads on the floor, then we push. After six hours of effort and plenty of sweat, Kibo reaches the destination, where we can finally start the test.



Procedure for moving Kibo's PM inside the test facility

The 15 ton PM is moved as shown below.





1.Kibo is put on plates called Air-skates, that expel compressed air to float the load. The blue plate is the Air-skate. Two Air-skates are installed at the front and back of Kibo respectively.


2.If air leaks from the junctions of floor tiles, Kibo does not float. To avoid this, we construct a path by placing aluminum plates on the floor covering the plate junctions with adhesive tape.


3.Compressed air is expelled to float Kibo so it can be moved by hand.


4.When Kibo reaches the end of the aluminum path, we move the aluminum plate forward and repeat this until Kibo reaches its destination.
5.After 30 minutes of effort, we could move this much. In spite of the air conditioning, working in clean room overalls causes heavy sweat.


Last Updated : August.6, 1999

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