EigoPro 準1級読解 — The Junkyard in Orbit

The region of space just above the atmosphere, once imagined as an infinite and pristine void, has quietly become one of humanity's most crowded—and most hazardous—frontiers. Decades of satellite launches, spent rocket stages, and the occasional deliberate destruction of a defunct satellite have left low Earth orbit littered with millions of fragments. Most are smaller than a marble, yet because they travel at speeds approaching twenty-eight thousand kilometres per hour, even a fleck of paint can puncture a spacecraft's hull. The orbital commons, in other words, is filling up with debris that no one owns and no one is obliged to remove. What makes the problem genuinely alarming is its capacity to feed on itself. In 1978 the physicist Donald Kessler warned that beyond a certain density, collisions would generate new fragments faster than atmospheric drag could clear them away. Each impact would beget further impacts, until cascading wreckage rendered whole orbital bands unusable for generations. This "Kessler syndrome" is no longer a distant hypothetical: in 2009 an active communications satellite collided with a derelict Russian craft, scattering thousands of trackable pieces in an instant. Operators of the International Space Station now routinely fire its thrusters to dodge approaching objects. Solutions exist on paper—nets, harpoons, lasers, and tugs designed to drag dead satellites downward—but every one of them runs into the same wall. Cleaning up debris is expensive, and the object you remove is almost never your own. Why should one nation shoulder the cost of disposing of another's discarded hardware? Until that incentive problem is solved, the experts contend, the technology will remain a series of promising demonstrations rather than a working service. The sky may look empty, but the bill for treating it as a bottomless dumping ground is already coming due.

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この単元の問題を3問、解説つきで公開しています

準1級 · 読解 · 全5問

問 1

What is the main idea of the passage?

Satellite launches should be banned until low Earth orbit has been completely cleared.
The technology to remove debris has been perfected but governments refuse to use it.
Orbital debris is an accelerating, self-perpetuating hazard whose cleanup is blocked mainly by economic and ownership problems.
Spacecraft hulls are now so well armoured that small debris poses no real threat.

Phrase

debris that no one owns and no one is obliged to remove

準1級読解宇宙科学ジャーナリズム主旨把握

⚡ひとことで

本文の論旨は「軌道デブリは自己増殖する危険で、清掃を阻むのは費用と所有権の問題」。

選択肢の解説Choice Analysis

「Orbital debris is an accelerating, self-perpetuating hazard whose cleanup is blocked mainly by economic and ownership problems.」

正解

本文は (1) 低軌道がデブリで満ちつつある→ (2) その危険は『自己増殖する (feed on itself / Kessler syndrome)』→ (3) 技術はあるが費用と所有権 (the object you remove is almost never your own) で実用化できない、という構成。よって「加速的で自己増殖するデブリの危険であり、清掃を阻むのは主に経済・所有権の問題」が主旨。

「Spacecraft hulls are now so well armoured that small debris poses no real threat.」
= 船体が頑丈で脅威でない ━ 本文は逆に『塗料片でも船体を貫ける』と危険性を強調しており正反対。
「The technology to remove debris has been perfected but governments refuse to use it.」
= 技術は完成済みだが政府が使用拒否 ━ 本文は技術が『紙の上では存在する (on paper)』段階で完成していないと述べており言い過ぎ。
「launches should be banned」
= 打ち上げを全面禁止すべき ━ 本文に打ち上げ禁止の主張はない。論点は清掃のインセンティブ。

▦Collocation

パターン	意味	例
feed on itself	自己増殖する	The problem can feed on itself.
the orbital commons	軌道という共有地	The orbital commons is filling up.
be obliged to V	~する義務がある	No one is obliged to remove it.
fill up with ~	~で一杯になる	Orbit is filling up with debris.
come due	支払期限が来る	The bill is coming due.

❝例文

The orbital commons is filling up with debris no one owns.
軌道という共有地は誰も所有しないデブリで一杯になりつつある。
The crisis has begun to feed on itself.
その危機は自己増殖し始めた。
No one is obliged to clean up the mess.
誰もその散らかりを片付ける義務がない。

💡Tip · 覚えるコツ

主旨設問は最終段の総括文を探すと速い。本文末の『treating it as a bottomless dumping ground』が問題の核を要約している。

問 2

Why can even tiny fragments of debris damage a spacecraft?

They tend to clump together into large masses before impact.
They move at extremely high orbital speeds, so even a fleck of paint can pierce a hull.
They are made of unusually dense and hardened metal alloys.
They carry an electric charge that corrodes a spacecraft's surface.

Phrase

they travel at speeds approaching twenty-eight thousand kilometres per hour, even a fleck of paint can puncture a spacecraft's hull

準1級読解宇宙科学ジャーナリズム詳細把握

⚡ひとことで

極めて高速 (時速約2万8千km) なので、塗料片でも船体を貫ける。

選択肢の解説Choice Analysis

「They move at extremely high orbital speeds, so even a fleck of paint can pierce a hull.」

正解

第1段で『速度が時速約2万8千kmに迫るため、塗料片 (a fleck of paint) でも船体 (hull) を貫ける (puncture)』と明示。つまり危険の原因はサイズではなく速度。これを言い換えた「極めて高い軌道速度で動くため、塗料片でも船体を貫ける」が正解。

「dense and hardened metal alloys」
= 高密度で硬化した合金製 ━ 本文は素材ではなく『速度』を原因とする。多くは塗料片など微小物。
「clump together into large masses」
= 大きな塊に固まる ━ 本文に凝集の記述はない。むしろ無数の小片のまま。
「They carry an electric charge that gradually corrodes a spacecraft's outer surface.」
= 腐食させる電荷を帯びる ━ 電荷・腐食の記述は本文にない。

▦Collocation

パターン	意味	例
travel at speeds approaching ~	~に迫る速度で進む	fragments travelling at high speed
puncture a hull	船体に穴を開ける	even paint can puncture the hull
a fleck of ~	~のかけら	a fleck of paint
spent rocket stage	使用済みロケット段	spent rocket stages in orbit
be littered with ~	~が散乱している	Orbit is littered with fragments.

❝例文

Even a fleck of paint can puncture a spacecraft's hull.
塗料のかけらでも宇宙船の船体を貫ける。
The fragments travel at speeds approaching 28,000 km/h.
破片は時速2万8千kmに迫る速度で進む。
Low orbit is littered with millions of fragments.
低軌道には数百万の破片が散乱している。

💡Tip · 覚えるコツ

detail 設問は本文の因果 (speed → puncture) を保持した選択肢が正解。素材・電荷など本文にない属性を足した肢は除外。

問 3

According to the passage, what did Donald Kessler predict?

Atmospheric drag would eventually clear all debris within a single generation.
Beyond a certain density, collisions would create new fragments faster than they could be removed, triggering a cascade.
Deliberately destroying old satellites would be the safest way to manage debris.
Active satellites would soon outnumber the pieces of debris in orbit.

Phrase

collisions would generate new fragments faster than atmospheric drag could clear them away

準1級読解宇宙科学ジャーナリズム詳細把握

⚡ひとことで

Kessler の予測=一定密度を超えると衝突が清掃を上回り、連鎖が起きる。

選択肢の解説Choice Analysis

「Beyond a certain density, collisions would create new fragments faster than they could be removed, triggering a cascade.」

正解

第2段で Kessler は『一定の密度を超えると、衝突が大気抵抗による除去より速く新たな破片を生み (generate ... faster than ... could clear them away)、各衝突がさらなる衝突を生む (each impact would beget further impacts)』と警告したとある。これを言い換えた選択肢が正解。

「drag would eventually clear all debris」
= 大気抵抗が全デブリを除去する ━ 本文は逆に『抵抗が追いつかない』と予測しているので正反対。
「Deliberately destroying the old satellites would be by far the safest way to manage the whole debris problem.」
= 古い衛星の破壊が最も安全 ━ 意図的破壊はむしろデブリ源として否定的に言及されている。
「active satellites would soon outnumber the pieces」
= 稼働衛星が破片を上回る ━ Kessler の予測内容ではなく本文にない。

▦Collocation

パターン	意味	例
beget ~	~を生み出す	Each impact begets further impacts.
clear ~ away	~を一掃する	Drag could not clear them away.
a distant hypothetical	遠い仮説	no longer a distant hypothetical
render ~ unusable	~を使用不能にする	wreckage rendered the band unusable
fire one's thrusters	スラスターを噴射する	The ISS fires its thrusters to dodge debris.

❝例文

Each collision could beget further collisions.
各衝突はさらなる衝突を生みうる。
Drag cannot clear the fragments away fast enough.
大気抵抗は破片を十分速く一掃できない。
The cascade would render whole orbits unusable.
その連鎖は軌道全体を使用不能にするだろう。

💡Tip · 覚えるコツ

人物の予測を問う設問は、その人物名 (Kessler) の直後の that 節・warned that ... を狙う。比較級 faster than が因果の核。

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EigoPro 準1級 読解 — The Junkyard in Orbit

この単元の問題を3問、解説つきで公開しています

debris that no one owns and no one is obliged to remove

they travel at speeds approaching twenty-eight thousand kilometres per hour, even a fleck of paint can puncture a spacecraft's hull

collisions would generate new fragments faster than atmospheric drag could clear them away

EigoPro 準1級読解 — The Junkyard in Orbit