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Spacecraft flew hundreds of thousands to hundreds of millions of kilometers from the earth, injecting speed when the size and direction of a slight error, arrived at target planets will appear large deviation error, for example, when Mars probe injecting speed 1 m/s speed (about one over ten thousand), arrived at Mars, about 100000 km distance deviation. Therefore, precise control and navigation must be carried out during the long flight. Flying to the moon is usually controlled by the orbital control system of the ground and space probe (see orbit control). Interplanetary flight distances, radio signal transmission time is long, the real-time remote control, can't so planets and interplanetary spacecraft orbit control system shall have the ability of autonomous navigation (see interstellar travel navigation and control). The United States, for example, "pirates" spacecraft in space flight of more than eight hundred million km, for 11 months of 2000 times of autonomous orbit adjustment, the final surface to achieve a soft landing on Mars, placement accuracy up to 50 km. In addition, in order to ensure the accuracy of the orbit control engine, the communication antenna is always aimed at the earth, and other systems work normally, and the detector has the autonomous attitude control ability
Review: Androstenone is a sexual hormone that's now being marketed to assist men attract the fairer sex. Advertisements for that oil based cologne claim that men wearing Androstenone are able to get more women compared to those that don't. The product could be dabbed on and possesses a shelf life of a minimum of 4 hours though some men report the scent lasting for 8 or maybe more hours.
Unfortunately, there is a disadvantage in alloy wheels. While they do look great and run smoothly, also, they are softer and fewer durable than steel wheels. Many appear in 2 or more parts at the same time, that will make the challenge worse. They could be damaged easily, and replacement wheels can be extremely expensive. Replacing a damaged wheel will be the safest and quite a few efficient strategy to the problem, but why can you want to replace a wheel measuring only slightly damaged? Alloy wheels can be repaired, plus a repair will always be a whole lot less than an upgraded.
It is also known as welding long rail line, which is a kind of line that welded normal rails without rail seam. The welding rail is not less than 200 meters long, and the actual application is usually 800~1000 meters or more. The long track is laid in the specified temperature range and fixed on the pillow. The long rail ends with a rail joint, while the middle part cannot scale up and down with the temperature. Therefore, there will be a great temperature pressure in the middle of the rail during the summer, which will produce a great temperature tension in winter. The greatest pressure on the rail and tension according to the years of rail laying and the highest temperature and minimum temperature calculation, rail tracks the maximum pressure should not cause to drum up by maximum tension should not cause rail fracture
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