题型:阅读理解 题类:模拟题 难易度:普通
江西省宜春市2020届高三英语5月模拟考试卷
Two years ago, aerospace manufacturer SpaceX shocked the world by landing its reusable booster (助推器) engine-the biggest and most costly part of the rocket used to power spacecraft into low orbit-on an autonomous drone ship in the Atlantic Ocean. Now, California-based startup Rocket Lab, has come up with an even more courageous idea: using parachutes and helicopters to capture the returning booster, or first stage as it is often called, in the air!
Rocket Lab's decision to avoid the propulsive or vertical (垂直的) landing used by SpaceX comes from its business model to keep its Electron rockets small and cost-effective. Standing just 57 feet tall, they are designed to deliver smaller payloads (有效载重) of about 500 pounds for only $5 million a launch. In contrast, the Spaced Falcon 9 rocket measuring 229 feet tall can lift up to 50,000 pounds, costs about $62而Ilion a mission. "We're not in the business of building medium-sized launch vehicles but small ones for customers to get on orbit frequently," said Rocket Lab CEO Peter Beck.
Similar to other rockets, the Electron divides into two once it reaches outer space. While the top part, carrying the load, continues on to its final destination, the booster engine falls back to Earth. The company intends to fix a ballute-a parachute-like braking device-to quickly slow down the booster's supersonic speed (超声速) upon its return into the atmosphere. Once it slows down to a reasonable pace, a helicopter will grab the rocket from midair and put it onto an awaiting ship to transport to the company's headquarters. Beck said: "The grand goal here is that if we can capture the vehicle in wonderful condition, in theory, we should be able to put it back on the pad, charge the batteries up, and go again."
The idea, still in the concept stage, will become one step closer to becoming a reality during Electron's next launch, scheduled for sometime in 3 years. "Engineers will carefully monitor the first stage as it returns, testing its ability to guide its landing with-he best way to slow down its speed," said Beck.
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