实施了违反治安管理行为,主动承认错误并及时改正的,可以从轻或免予处罚。()
查看答案
The first challenge of space exploration was developing rockets powerful enough and reliable enough to boost a satellite into orbit. These boosters needed more than brute force, however; they also needed guidance systems to steer them on the proper flight paths to reach their desired orbits. The next challenge was building the satellites themselves. The satellites needed electronic components that were lightweight, yet durable enough to withstand the acceleration and vibration of launch. Creating these components required the world's aerospace engineering facilities to adopt new standards of reliability in manufacturing and testing. On Earth, engineers also had to build tracking stations to maintain radio communications with these artificial "moons" as they circled the planet.
Beginning in the early 1920s, humans launched probes to explore other planets. The distances traveled by these robotic space travelers required travel times measured in months or years. These spacecraft had to be especially reliable to continue functioning for a decade or more. They also had to withstand such hazards as the radiation belts surrounding Jupiter, particles orbiting in the rings of Saturn, and greater extremes in temperature than are faced by spacecraft in the closeness of Earth. Despite their great scientific returns, these missions often came with high price tags. Today the world' s space agencies, such as the United States National Aeronautics and Space Administration (NASA. and the European Space Agency (ESA), strive to conduct robotic missions more cheaply and efficiently.
It was inevitable that humans would follow their unpiloted creations into space. Piloted space flight introduced a whole new set of difficulties, many Of them concerned with keeping people alive in the hostile environment of space. In addition to the vacuum of space, which requires any piloted spacecraft to carry its own atmosphere, there are other deadly hazards: solar and cosmic radiation, micrometorites (small bits of rock and dus0 that might puncture a spacecraft hull or an astronaut' s pressure suit, and extremes of temperature ranging from frigid darkness to broiling sunlight. It was not enough simply to keep people alive in space — astronauts needed to have a means of accomplishing useful work while they were there. It was necessary to develop tools and techniques for space navigation, and for conducting scientific observations and experiments. Astronauts would have to be protected when they ventured outside the safety of their pressurized spacecraft to work in the vacuum. Missions and hardware would have to be carefully designed to help insure the Safety of space crews in any foreseeable emergency, from liftoff to landing.
The challenges of conducting piloted space flights were great enough for missions that orbited Earth. They became even more daunting for the Apo
A. Those explorations.
B. The advance of new technologies.
C. Spacecraft studies.
D. Scientific discoveries.
What was Susan's motive for carrying on the project?
A. Her passion.
B. Her administrator's demand.
C. Peer pressure.
D. Students' encouragement.
警察是具有武装性质的维护社会秩序、保卫国家安全的司法机关。()
A. 正确
B. 错误
社会监督主体可以通过批评、建议、申诉、控告等监督形式对公安机关的执法行为进行监督。()
A. 正确
B. 错误