Extensible boom, solar cell paddle, and extensible boom manufacturing method

An extensible boom manufacturing method comprising:

• stretching a center portion in an extending direction of a woven prepreg along the extending direction, the woven prepreg being made of a plurality of fibers along a first direction and a plurality of fibers along a second direction;
• and
• forming the stretched woven prepreg into a cylindrical shape with an axis parallel to the extending direction as a center axis, wherein
• an angle formed by the first direction to a clockwise direction with respect to the extending direction is a negative angle,
• an angle formed by the second direction to the clockwise direction with respect to the extending direction is a positive angle,
• an angle formed by a first low-angle direction to the clockwise direction with respect to the extending direction is an angle larger than-45 degrees and is larger than the angle formed by the first direction to the clockwise direction with respect to the extending direction, the first low-angle direction being a direction along which the fiber arranged in the center portion of the stretched woven prepreg goes and which forms a negative angle to the clockwise direction with respect to the extending direction, and
• an angle formed by a second low-angle direction to the clockwise direction with respect to the extending direction is an angle smaller than 45 degrees and is smaller than the angle formed by the second direction to the clockwise direction with respect to the extending direction, the second low-angle direction being a direction along which the fiber arranged in the center portion of the stretched woven prepreg goes and which forms a positive angle to the clockwise direction with respect to the extending direction.