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NASA spacecraft delivering biggest sample yet from an asteroid
Planet Earth is about to receive a special delivery — the biggest sample yet from an asteroid.
A NASA spacecraft will fly by Earth on Sunday and drop off what is expected to be at least a cupful of rubble it grabbed from the asteroid Bennu, closing out a seven-year quest.
The sample capsule will parachute into the Utah desert as its mothership, the Osiris-Rex spacecraft, zooms off for an encounter with another asteroid.
Scientists anticipate getting about a half pound (250 grams) of pebbles and dust, much more than the teaspoon or so brought back by Japan from two other asteroids. No other country has fetched pieces of asteroids, preserved time capsules from the dawn of our solar system that can help explain how Earth — and life — came to be.
Sunday’s landing concludes a 4 billion-mile (6.2-billion-kilometer) journey highlighted by the rendezvous with the carbon-rich Bennu, a unique pogo stick-style touchdown and sample grab, a jammed lid that sent some of the stash spilling into space, and now the return of NASA’s first asteroid samples.
“I ask myself how many heart-pounding moments can you have in one lifetime because I feel like I might be hitting my limit,” said the University of Arizona’s Dante Lauretta, the mission’s lead scientist.
A brief look at the spacecraft and its cargo:
THE LONG JOURNEY
Asteroid chaser Osiris-Rex blasted off on the $1 billion mission in 2016. It arrived at Bennu in 2018 and spent the next two years flying around the small spinning space rock and scouting out the best place to grab samples. Three years ago, the spacecraft swooped in and reached out with its 11-foot (3-meter) stick vacuum, momentarily touching the asteroid’s surface and sucking up dust and pebbles. The device pressed down with such force and grabbed so much that rocks became wedged around the rim of the lid. As samples drifted off into space, Lauretta and his team scrambled to get the remaining material into the capsule. The exact amount inside won’t be known until the container is opened.
ASTEROID BENNU
Discovered in 1999, Bennu is believed to be a remnant of a much larger asteroid that collided with another space rock. It’s barely one-third of a mile (half a kilometer) wide, roughly the height of the Empire State Building, and its black rugged surface is packed with boulders. Roundish in shape like a spinning top, Bennu orbits the sun every 14 months, while rotating every four hours. Scientists believe Bennu holds leftovers from the solar system’s formation 4.5 billion years ago. It may come dangerously close and strike Earth on Sept. 24, 2182 — exactly 159 years after the asteroid’s first pieces arrive. Osiris-Rex’s up-close study can help humanity figure out how to deflect Bennu if needed, Lauretta said.
GAME DAY
Osiris-Rex will release the sample capsule from 63,000 miles (100,000 kilometers) out, four hours before it’s due to touch down at the Defense Department’s Utah Test and Training Range on Sunday morning. The release command will come from spacecraft builder Lockheed Martin’s control center in Colorado. Soon afterward, the mothership will steer away and take off to explore another asteroid. The capsule — nearly 3 feet wide (81 centimeters) and 1.6 feet tall (50 centimeters) — will hit the atmosphere at 27,650 mph (44,500 kph) for the final 13 minutes of descent remaining. The main parachute will slow the last mile (1.6 kilometers), allowing for a mild 11 mph (18 kph) touchdown. Once everything is deemed safe, the capsule will be hustled by helicopter to a makeshift clean lab at the range. The next morning, a plane will carry the sealed container full of rubble to Houston, home to NASA’s Johnson Space Center. NASA is livestreaming the touchdown, set for around 10:55 a.m. EDT.
CLEANER THAN CLEAN
A new lab at Johnson will be limited to the Bennu rubble to avoid cross-contamination with other collections, said NASA curator Kevin Righter. Building 31 already holds the moon rocks brought back by the Apollo astronauts from 1969 through 1972, as well as comet dust and specks of solar wind collected during two previous missions and Mars meteorites found in Antarctica. The asteroid samples will be handled inside nitrogen-purging gloveboxes by staff in head-to-toe clean room suits. NASA plans a splashy public reveal of Bennu’s riches on Oct. 11.
ASTEROID AUTUMN
This fall is what NASA is calling Asteroid Autumn, with three asteroid missions marking major milestones. The Osiris-Rex touchdown will be followed by the launch of another asteroid hunter on Oct. 5. Both the NASA spacecraft and its target — a metal asteroid — are named Psyche. Then a month later, NASA’s Lucy spacecraft will encounter its first asteroid since soaring from Cape Canaveral, Florida, in 2021. Lucy will swoop past Dinkinesh in the main asteroid belt between Mars and Jupiter on Nov. 1. It’s a warmup for Lucy’s unprecedented tour of the so-called Trojans, swarms of asteroids that shadow Jupiter around the sun. Neither Psyche nor Lucy will collect souvenirs, nor will Osiris-Rex on its next assignment, to explore the asteroid Apophis in 2029.
OTHER SAMPLE RETURNS
This is NASA’s third sample return from deep space, not counting the hundreds of pounds (kilograms) of moon rocks gathered by the Apollo astronauts. The agency’s first robotic sample grab ended with a bang in 2004. The capsule bearing solar wind particles slammed into the Utah desert and shattered, compromising the samples. Two years later, a U.S. capsule with comet dust landed intact. Japan’s first asteroid sample mission returned microscopic grains from asteroid Itokawa in 2010. It’s second trip yielded about 5 grams — a teaspoon or so— from the asteroid Ryugu in 2020. The Soviet Union transported moon samples to Earth during the 1970s, and China returned lunar material in 2020.
注释：
quest: v; n
表示" 探索；寻求"，means " look for;search"，如：This fruitless quest was called alchemy by the Arabs. 这种无谓的的探索被阿拉伯人称作炼金术。
pogo: n
表示" 弹簧单高跷"，如：Scenes include a naked man being showered with bits of paper, men doing the pogo, and a man and woman engaged in tentative ballet while conducting a dialogue about genocide. 从舞台场景来看，有的是无数纸片洒落到一名赤裸身躯的男子身上，有的是一群男子踩着弹簧单高跷，还有一男一女跳着若是若非的芭蕾，仿佛是在相互诉说着一场灭族屠杀。
stash: v; n
表示" 隐藏；储藏"，means "save up as for future use"，如：And you will have your personal garage to stash your rides. 你将拥有自己的个人修车场以隐藏你的赛车。
scout: v
表示" 侦察；物色;侦察员"，means "act as a scout; a person, ship or aircraft sent out to get information about the enemy's position"，如：Three planes were sent up to scout. 派出三架飞机侦察The scout spurred on to the destination. 侦察员向目的地疾驰而去。
swoop: v
表示" 抓取；猛扑"，means "move down on as if in an attack"，如：The robber swooped up the banknotes. 劫匪把钞票一把抢走了。
momentarily: adv
表示" 暂时地；立刻地"，means "for an instant or moment"，如：His mind blanked out momentarily. 他一时走神了。
wedge: v
表示" 楔住；嵌；挤进"，means "fix tightly as with a wedge"，如：Please wedge this cabinet to keep it from tipping.请在橱底楔入楔子以防它倾斜。
remnant: adj; n
表示" 剩余的;残存者"，means "remaining; a part that remains"，如：The beautiful curtain is made of remnant materials.这个漂亮的窗帘是用零头布做的。I will sell this remnant to you, at cost. 我愿将此剩货照成本卖给你。
Rugged：adj
表示"高低不平的；崎岖的；"，means "sturdy and strong in constitution or construction; enduring"，如：They walk on the rugged country road. 他们在崎岖不平的乡村小路上走着。
hustle: v; n
表示" 催促；赶紧做"，means "(cause to) move fast"，如：The mother hustled the children off to school and started working. 母亲打发孩子们赶快去上学，然后就开始干起活来。
speck: v; n
表示" 用斑点标记; 斑点"，means "produce specks in or on"，如：You can't eat bread covered with dark specks. 你可不能吃满是黑斑的面包啊。
purge: v
表示" 净化；清除；清洗"，means " get rid of (unwanted people) in (a state,political,etc.) "，如：We may purge water by distillation. 我们可以用蒸馏法使水净化。
intact: adj
表示"原封不动的"，means " undamaged; complete"，如：Despite his misfortunes, his faith and optimism remained intact. 虽然他遭到一连串的不幸，他的信心和乐观丝毫未减。
microscopic: adj
表示"极小的；微观的"，means "of or relating to or used in microscopy"，如：It's impossible to read his microscopic handwriting. 不可能看清他那极小的书写字迹。
中文简要说明：
美国太空总署NASA的小行星探测器「欧西里斯-雷克斯」(Osiris-Rex)于星期日飞掠地球，它将带回大约一茶杯量(250公克)的小行星岩石样本，完成为期七年的探索任务中，最重要的一部分。
美联社报导，探测器在飞掠地球时，会抛出有着隔热罩的返回舱，与大气层剧烈摩擦后，将会进入美国犹他州沙漠上空，开启降落伞落地。同时返回舱会持续发出的电波讯号，引导回收团队找到并带回实验室。至于欧西里斯-雷克斯探测器，它并不会着陆地球，而是前往另一颗小行星，继续它的太空调查任务。
先前，日本隼鸟2号探测器(Hayabusa2)曾经在龙宫小行星(Ryugu)发回5.4克的有效样本；而美国的任务则带回250克，数量要多得多。更多并且来源不同的小行星样本，能够帮助科学家研究太阳系诞生之初，那些固体物质的成份，或许能解释地球和生命是如何形成的。
小行星贝努 (Bennu)于 1999年被发现，体积非常的小，直径只有500公尺里，相当于纽约帝国大厦的高度，科学家猜测，它可能是两颗小行星撞击后的残余物它并不在火星与木星之间的小行星带，而是「阿波罗族小行星」，这族的小行星的轨道很大程度与地球轨道有交错，以贝努为例，它平均每14 个月绕太阳一周，所以它有可能与地球过于接近，甚至相撞。科学家预估，贝努可能会在 2182 年 9 月 24 日极度接近地球，有大约三百分之一的概率被地球吸引而撞击。所以，欧西里斯-雷克斯的近距离研究，可以帮助我们确定它贝努成分，如果真的会撞地球，那么该在什么时间推它一把，好偏离撞击路线。
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