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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
1. Redirects: To check the redirects status, you just need to login to Google's Search Console, then go to Crawl > Crawl Errors and select the 'Not Found' tab. In this section, you'd be able to find the pages without redirects. If you have not create the appropriate redirects it would result in the drastic traffic loss.
For most babies, vaccination is safe. However, in order to reduce the occurrence of adverse reactions, new mothers can understand the variety, role, taboos, adverse reactions and matters needing attention before vaccination. Cooperate with the doctor to provide the baby's health condition and the inoculation.
Signs of birth. Since the middle of the 20th century, technology has grown faster and faster. It was only six and a half years since the discovery of uranium fission in January 1939 to the first atomic bomb exploded in July 1945. The emergence of electronic computers has led to more profound changes in the fields of human social life. These technological breakthroughs can be called technological revolutions
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