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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
As a matter of fact, there is no problem, but only situation that should be solved. In order to enforce acceptable network use policies and provide security including anti-virus, anti-malware or anti-spam services computer user can use proxy servers. To lessen network traffic plus an capability to enhance network security are the most tempting and indispensable functions of proxy servers. A proxy server enhances network security by controls for receiving and forwarding (or rejecting) requests between isolated networks, for instance, forwarding requests across a firewall. A proxy server lessens network traffic by rejecting unwanted requests, forwarding requests to balance and optimize server workload, and fulfilling requests by serving data from cache in lieu of unnecessarily contacting the true destination server.
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