GRE
发表于 2025-3-26 23:40:42
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统治人类
发表于 2025-3-27 03:36:16
The New Frontier,mulous canopies of elm forest and beyond the finest wisps of Earth’s life-giving atmosphere sits the Interplanetary Frontier. In crystal clarity, telescopes and space probes have returned photos of the strange environments of other solar-system worlds. Where in neary space might human settlements be
克制
发表于 2025-3-27 05:22:38
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Corral
发表于 2025-3-27 11:54:49
,The First “Green” Space Technologies,g space technologies to exploit the Near-Earth environment. To get into space astronauts and cosmonauts would use the high-technology rocket. But to return from orbital journeys, spacefarers would use frictional drag produced by Earth’s envelope of air. Another “green” space technology would also so
nugatory
发表于 2025-3-27 13:55:15
,Probes to the Planets:Where We’ve Been on Our Journey,ockets could escape the gravitational field of the Earth, navigate by the stars to cruise the depths of interplantety space, and begin the preliminary reconnaissance of the solar system. This was a very heady time for space scientist—war rockets, launched iln a superpower competition, would actually
语言学
发表于 2025-3-27 18:45:17
Breaking Out into Space:Visionary Futures,ntion wisdon says that the Earth is filled up, and large self-suffcient lunar colony might be impossible due to lack of water and other essential volatiles. Mars, barely habitable, might be altered to support terrestrial life, but at a Herculean effort and enormous cost over millennial duration. Con
Mutter
发表于 2025-3-27 22:19:40
Thinking Interstellar,simple” as sending one to another of the nine planets in our solar system—a feat, by the way, that we have not yet achieved. (Pluto has not yet been explored, though a mission to do so dubbed, “New Horizons”, is on its way to that distance—distances so vast that they cannot be easily comprehended; d
exorbitant
发表于 2025-3-28 04:19:51
,Space Brakes(“Living of the Land” by Using a Planetary Atmosphere),ion. Planetary atmospheres provide a tremendous resources for explorers who want to minimize the amount of propulsion they must carry from the home planet and, potentially, reduce interplanetary trip times. By allowing a spacecraft to have a controlled entry into the upper atmosphere of a planet, th
Chandelier
发表于 2025-3-28 09:10:43
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结合
发表于 2025-3-28 13:40:47
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