MESSENGER Spacecraft Will Be First to Orbit Planet Mercury
The U.S. space probe MESSENGER is poised 1 to enter orbit around Mercury(水银) early Friday, Universal time, capping a nearly seven-year journey to the solar system’s innermost planet. Scientists with the U.S. space agency, NASA, hope the orbiting probe will greatly expand our knowledge of Mercury, and provide news clues to the origins(起源) of Earth, as well.
MESSENGER’s orbital rendezvous 2 with Mercury is the final stage of a breathtaking journey that has taken it billions of kilometers through the inner solar system, including half dozen photographic fly-bys of Earth, Venus and Mercury itself for gravitational assists.
"Those were all hor d’oeuvres for the banquet we’re about to enjoy," said Sean Solomon of the Carnegie Institution of Washington D.C. , who is the MESSENGER mission’s principal investigator 3. "Once MESSENGER is in orbit around Mercury, it will be the first spacecraft to do so, we will have the first global observatory 4 at the innermost planet of the solar system."The last close-up data on Mercury was collected by NASA’s Mariner 5 10 in a fly-by mission in the mid-1970s.
Fifteen minutes before insertion into Mercury orbit, MESSENGER will begin firing its main thruster engine, burning off one-third of its propellant. That burn will slow the spacecraft down by 862 meters per second for the orbit insertion maneuver 6.
Scientists say it will be an hour before they are able to confirm whether MESSENGER is securely in orbit around Mercury.
MESSENGER will circle the tiny planet, roughly the size of Earth’s Moon, every 12 hours, traveling over the planet’s polar regions just 200 kilometers above the rocky surface.
MESSENGER will be a mere 7 46 million kilometers from the Sun. Built to withstand the blistering 8 heat, the spacecraft is carrying seven scientific instruments that mission investigator(研究者) Solomon hopes will help answer some intriguing 9 questions about the solar system’s inner-most planet.
For example, Solomon says there appears to be ice in the floors of impact craters 10 at Mercury’s poles, which are in permanent shadow.
"That’s pretty astonishing because at the equator of Mercury, the temperature varies between day and night by 600 degrees centigrade," he said. "So, the notion that there might be permanent repositories of water ice at the poles of Mercury seems to fly in the face of the fact that this is a planet closest to the Sun and has extraordinarily 11 high daytime temperatures."Solomon says MESSENGER won’t begin returning any images of Mercury until April.
MESSENGER’s orbital mission is scheduled to last one year. But Solomon is hopeful there will be enough fuel to extend its observations of Mercury into a second year.(本文由在线英语听力室整理编辑)
- The hawk poised in mid-air ready to swoop. 老鹰在半空中盘旋,准备俯冲。
- Tina was tense, her hand poised over the telephone. 蒂娜心情紧张,手悬在电话机上。
- She made the rendezvous with only minutes to spare.她还差几分钟时才来赴约。
- I have a rendezvous with Peter at a restaurant on the harbour.我和彼得在海港的一个餐馆有个约会。
- He was a special investigator for the FBI.他是联邦调查局的特别调查员。
- The investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。
- Guy's house was close to the observatory.盖伊的房子离天文台很近。
- Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。
- A smooth sea never made a skillful mariner.平静的大海决不能造就熟练的水手。
- A mariner must have his eye upon rocks and sands as well as upon the North Star.海员不仅要盯着北极星,还要注意暗礁和险滩。
- All the fighters landed safely on the airport after the military maneuver.在军事演习后,所有战斗机都安全降落在机场上。
- I did get her attention with this maneuver.我用这个策略确实引起了她的注意。
- That is a mere repetition of what you said before.那不过是重复了你以前讲的话。
- It's a mere waste of time waiting any longer.再等下去纯粹是浪费时间。
- The runners set off at a blistering pace. 赛跑运动员如脱缰野马般起跑了。
- This failure is known as preferential wetting and is responsible for blistering. 这种故障称为优先吸湿,是产生气泡的原因。 来自辞典例句
- These discoveries raise intriguing questions. 这些发现带来了非常有趣的问题。
- It all sounds very intriguing. 这些听起来都很有趣。 来自《简明英汉词典》
- Small meteorites have left impact craters all over the planet's surface. 这个行星的表面布满了小块陨石留下的撞击坑。 来自《简明英汉词典》
- The battlefield was full of craters made by exploding shells. 战场上布满弹坑。 来自《现代英汉综合大词典》
- She is an extraordinarily beautiful girl.她是个美丽非凡的姑娘。
- The sea was extraordinarily calm that morning.那天清晨,大海出奇地宁静。