**2. Measurement of solar array paddle motion**

The reason why past trials failed to observe the phenomena described above might be that the motion of the solar array paddle is too small or slow to be observed by such onboard sensors as an accelerometer. Therefore, JAXA decided to measure the phenomena by using an onboard camera that was originally mounted on the satellite to monitor solar array pad‐

dle deployment (Fig. 2). (For GOSAT, the solar array paddle consists of three solar panels, a yoke, wires that control deploying speed, and hinge/latch mechanisms that connect the pan‐ els and yoke.) A small CCD/CMOS camera (Fig. 4) is mounted on most JAXA satellites to monitor solar array paddle deployment, as failure to deploy the solar array paddle would become critical failure of the satellite itself. We thus developed a system that uses this CMOS camera to measure the distortion and vibration of the solar array paddle, with said vibration being measured as follows:

For GOSAT, the solar array paddle consists of three solar panels, a yoke, wires that control

Vibration of Satellite Solar Array Paddle Caused by Thermal Shock When a Satellite Goes Through the Eclipse

http://dx.doi.org/10.5772/52626

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As the onboard camera used for this experiment was originally designed to monitor the de‐ ployment of a folded solar array paddle, its field of view is thus as wide as 90 [deg] (Fig. 5), while the camera's number of pixels is limited to SXGA (1280 X 1024 pixels). The size of the markers is also limited to 50 [mm] X 26 [mm], while distance from the camera to the target markers is as far as 6 [m]. These constraints mean that one pixel of the camera is equivalent to 7 [mm] at the target marker's position. Therefore, a technique for processing sub-pixel

level image data is required to identify deformation of the solar array paddle.

deploying speed, and hinge/latch mechanisms that connect the panels and yoke.

**Figure 3.** Target markers on the solar array paddle

**Figure 4.** CMOS camera and LED lights

**3. Measurement algorithm**


**Figure 1.** JAXA's earth observation satellite "GOSAT"

**Figure 2.** Image taken by camera

For GOSAT, the solar array paddle consists of three solar panels, a yoke, wires that control deploying speed, and hinge/latch mechanisms that connect the panels and yoke.

**Figure 3.** Target markers on the solar array paddle

dle deployment (Fig. 2). (For GOSAT, the solar array paddle consists of three solar panels, a yoke, wires that control deploying speed, and hinge/latch mechanisms that connect the pan‐ els and yoke.) A small CCD/CMOS camera (Fig. 4) is mounted on most JAXA satellites to monitor solar array paddle deployment, as failure to deploy the solar array paddle would become critical failure of the satellite itself. We thus developed a system that uses this CMOS camera to measure the distortion and vibration of the solar array paddle, with said

**1.** Attach small reflective target markers at the end of the paddle (as shown in Fig. 3).

**2.** Take images from this camera and transmit them to the on-ground station. Fig. 2 is an

**3.** Identify the locations of the target markers in the camera view with image processing.

S-band Antenna

S-band Antenna

TANSO-CAI:

Nadir

Cloud and Aerosol sensor

Solar array panel

TANSO-FTS: Greenhouse Gases

Technical Data Acquisition Equipment (TEDA)

Sensor

**4.** Calculate displacement from the predicted target marker locations.

Monitor Camera(CAM)

X-band Antenna

**Figure 1.** JAXA's earth observation satellite "GOSAT"

**Figure 2.** Image taken by camera

Solar array panel

vibration being measured as follows:

334 Advances in Vibration Engineering and Structural Dynamics

image taken by the camera.

**Figure 4.** CMOS camera and LED lights
