Radiation Effect

Space is a dangerous place, not only because of meteors (流星)but also because of rays from the sun and other stars. The atmosphere again acts as our protective blanket on earth light, gets through, and this is essential for plants to make the food that we eat. Heat, too, makes our environment endurable. Various kinds of rays come through the air from outer space, but enormous quantities of radiation from the sun are screened off. As soon as men leave the atmosphere they are exposed to this radiation, but their spacesuits or the walls of their spacecrafts, if they are inside, do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space. The unit of radiation is called "rem" (“雷姆”). Scientists have reason to think that a man can put up with far more radiation than 0.1 rem without being damaged, the figure of 60 reins has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damage-a person may feel perfectly well, but the cells of his or her sex organs may be damaged ,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren. Missions of the Apollo flights have had to cross belts of high radiation and, during the outward and return journeys, the Apollo crew accumulated a larger amount of reins. So far, no dangerous amounts of radiation have been reported, but the Apollo missions have been quite short. We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere, working in a space laboratory. Drugs might help to decrease the damage clone by radiation ,but no really effective ones have been found so far.
The harm radiation has done to the Apollo crew members______.

A. Right
B. Wrong
C. Not mentioned

A new center that will coordinate co-operation was also announced (54) the European Commission, the European Space Agency (ESA) and the Chinese Ministry of Science and Technology not long (55) . The China-Europe Global Navigation Satellite System Technical Training and Cooperation Center will be (56) at Beijing University. China has a substantial satellite launch industry and could potentially help launch the Galileo satellites.
The US has claimed that Galileo could interfere (57) the US ability to downgrade (降级) the GPS service during military conflicts. European officials say this is unfounded and counter that US opposition (58) the commercial challenge Galileo would present to GPS. Galileo will be precise to within a meter, while the civilian GPS service is accurate to around 10 meters.
The Galileo satellite constellation (卫星群集) will (59) 27 operational and three reserve satellites orbiting the Earth at an altitude of 23,600 km. The satellites will be strung along three medium-Earth orbits at 56 degrees inclination to the equator and will provide global coverage. The system should be operational by 2008 and the entire project is expected to (60) around 3.2 billion Euros (USD 3.6 billion).
The European Commission has said Galileo will primarily be used for transportation technology, scientific research, land management and disaster monitoring. Galileo will provide two signals; a standard civilian one and an encrypted (编码) , wide-band signal (61) the Public Regulated Service (PRS). This second signal is designed to withstand localized jamming(干扰)and will be used by police and military services in Europe. European Commission (62) have said China will not be given access to the PRS.
The first Galileo satellite is scheduled to launch late in 2004. Clocks on board the (63) will be synchronized (使同步) through 20 ground sensors stations, two command centers and 15 uplink (向上传输) stations. Receivers on the ground will use time signals from the satellites to precisely calculate their (64) . A "search and rescue" function will also (65) distress signals be relayed through the constellation of satellites.