System-level evaluation tests

In the RISING-2 project, the hardware of FM is fabricated as another structures and instruments after finishing the development of EM. The severer test condition can be applied compared to fabricate only the EFM, and the ground verification can be carried out when the FM has a trouble in orbit.

Fig 1. Environmental tests for engineering model: a) electrical test, b) vibration test, c) thermal vacuum test

Electrical tests

The electrical tests were started in Nov. 2011 shown in Fig.7-a). A command transmitter and a telemetry receiver are required, which are also used in operation phase. These radio equipment is controlled by a GUI-based quick-look software (QL). The QL is refined through the electrical tests, and the final revision is used as operation ground software. The satellite-own command and telemetry formats are included in QL, so these formats must be defined in system specification documents in prior to tests. Also, the power supply unit which can be controlled by PC is required to imitate solar power generation.

Vibration test

The fabrication of EM structure was started in Jan. 2010, and the vibration tests of EM system were carried out in the span of May to Dec. in 2010, shown in Fig.7-b). In the first several tests, the mechanical test model (MTM) including dummy mass instruments is used, and they are replaced to EM instruments in final test.

In the phase of MTM tests, the total 4 tests were carried out in which structures with high-level vibration response were modified. The test results are analyzed using the software of Femap with NASTRAN if the design modification is valid before the structure is actually modified.

The separation mechanism is PAF239M developed by JAXA, but the originally designed dummy cylinder structure with 130-mm height was used in MTM tests. It was replaced to real PAF239M structure in final EM test, and the structure stiffness and the primary eigenvalues were almost similar. Also, the vibration measurement system with 16-ch accelerometer sensors was prepared by university, and it improved the test efficiency.

Thermal vacuum test

The thermal vacuum test was carried out in Dec. 2010 shown in Fig.7-c). The heaters are pasted on the outside panels of EM, and the temperature changes of structures and instruments are measured. Using this result, the thermal mathematical model was improved. Also, it was confirmed that each hardware unit can stably work in the high and low temperature range.

(C) The Space Robotics Lab (Space Exploration Lab), Tohoku University
Last-modified: 2011-06-16 (Thu) 08:29:27 (3395d)