2026年3月托福机经套卷(第1套)Read an Academic Passage5 道题

Space Debris: A Growing Concern

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Space Debris: A Growing Concern The Kessler Syndrome, proposed by NASA scientist Donald J. Kessler in 1978, hypothesizes a cascading effect in low Earth orbit (LEO) in which collisions between satellites and debris—defunct satellites, spent rocket stages, and fragments from earlier collisions—generate more fragments, exponentially increasing the likelihood of further collisions. This feedback loop could render certain orbital regions unusable for decades. While the model is compelling, some assumptions merit scrutiny. For instance, it presumes a uniform distribution of debris and constant collision probability, yet orbital mechanics suggest that debris clusters in specific altitudes and orbital paths, potentially limiting the scope of cascading events. Moreover, technological advancements in debris tracking and active removal may mitigate the risk more effectively than Kessler originally envisioned. Critics argue that the syndrome underestimates the resilience of orbital infrastructure and overstates the inevitability of runaway collisions. Alternative explanations for observed debris growth include a greater number of satellite launches and fragmentation from aging spacecraft, rather than a self-sustaining cascade. Nonetheless, the Kessler Syndrome remains a valuable heuristic for space policy, emphasizing the need for international cooperation and sustainable orbital practices. Its cautionary implications are profound—especially as commercial constellations dramatically increase the number of active satellites in LEO.

Question 1查看单题

The passage suggests that one impact of the Kessler Syndrome would be

Aan increase in NASA space research

Ba limitation on where satellites could safely orbit

Ca greater number of satellite launches

Dan increased risk of debris falling to Earth

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正确答案：B

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Question 2查看单题

Why does the author mention the assertion that "debris clusters in specific altitudes and orbital paths"?

ATo provide a reason for an increase in collisions between satellites and debris

BTo illustrate a part of the feedback loop

CTo explain an objection to the Kessler Syndrome hypothesis

DTo emphasize the need for better debris tracking

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正确答案：C

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Question 3查看单题

The word "resilience" in the passage is closest in meaning to

Astrength

Bthreat

Cknowledge

Dsupervision

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正确答案：A

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Question 4查看单题

According to the passage, some argue that the Kessler Syndrome will not occur for all of the following reasons EXCEPT:

ASpace debris may not be spread out as evenly as the theory assumes.

BNew technology means that the removal of debris may be possible.

CNASA has since developed new orbital infrastructure for avoiding collisions.

DThere may be other explanations for the observed growth in debris.

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正确答案：C

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Question 5查看单题

What does "Its cautionary implications" refer to in the passage?

AThe idea that one must assess the Kessler Syndrome carefully before accepting its predictions

BThe idea that there will be cascading collisions in LEO, making it difficult for satellites to remain intact

CThe suggestion that international cooperation will be more difficult to achieve as space becomes more cluttered

DThe suggestion that debris tracking and active removal may pose additional risks to satellites

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正确答案：B