|
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
Space probe according to the detection of object is divided into lunar probe, probe and interplanetary spacecraft, small body such as a space probe to leave the speed of the earth must be large enough to overcome or get rid of the earth's gravity, realize the deep space flight. The probe orbits the heliocentric elliptical orbit (double-cut orbit) that is tangent to the earth's orbit and the planet's orbit, and may meet the target planet; Increase speed to change the orbit, flew to target the planet can shorten the time in order to ensure the detector fly the double track to the planetary orbits and tangent with the target when the target planets also run to it, must be chosen in the earth and the target planet at a particular moment of relative position detector. Detector can fly around the star, the use of planetary gravitational fields accelerate continuous multiple planets orbit the significant characteristic of space probe is, flying in space for long time, the ground cannot real-time remote control, so must have the ability of autonomous navigation; To fly outside the solar system, away from the sun, solar arrays, and nuclear energy systems; It is necessary to adopt special protective structure to withstand very severe space environment. Landing or walking on the surface of the moon or planet requires some special form of structure
Through search engine optimization often known as SEO services an online site is enhanced and improved to have its full function and search engine rankings. There are several SEO services that the SEO company can offer to its clients. These services includes analyzing your client?s website, analyzing the competitor?s website, focusing on the development of your client?s website, and continuous maintenance of the website to retain its ranking online.
Reverse flushing can be done automatically: the backwash is done by hydraulic valve opening and hydraulic cylinder pistons, which are controlled by the backwash controller. The anti-flushing controller can accurately control the hydraulic valve and hydraulic cylinder according to the differential pressure value from the filter inlet and outlet, and the power of the controller comes from the pressure of the line itself.
New Car Buying Tips--



Copyright ?1998-2017 Technews Corp, All rights reserved
|
