Beta angle in the Earth's shadow, and results in extremely reduced absorption of solar energy. At a LEO of 280 kilometers, the object is in sunlight through 59% of its orbit (approximately 53 minutes in Sunlight, and 37 minutes in shadow.) On the other extreme, an object launched into an orbit parallel to the terminator results in a beta angle of 90 degrees (formula_2 = 90°), and the object is in sunlight 100% of the time. An example would be a polar orbit initiated at local dawn or dusk on an equinox. Beta angle can be controlled to keep a satellite as
Type 97 90 mm Infantry Mortar Type 97 90 mm Infantry Mortar The Type 97 90 mm Infantry Mortar was a simplified version of the Japanese Type 94 90 mm Infantry Mortar. The Type 97 designation was given to this gun as it was accepted in the year 2597 of the Japanese calendar (1937). The Type 90-mm mortar is a Stokes-Brandt type mortar similar in appearance to the US 81-mm mortar, M1 and the Japanese Type 97 81 mm piece. It is believed that the 90 mm weapon has been introduced later than its model number would imply, as a captured specimen was marked "Model 97