-
(单词翻译:双击或拖选)
By David McAlary
Washington
06 March 2006
The newest American mission to Mars is hurtling toward the red planet, due Friday to examine it in the sharpest detail yet. It will be the largest spacecraft to circle the planet, with big capabilities1 to match.
-----------------------------------------------
Since 1997, the U.S. space agency NASA has been dispatching orbiters and companion landers to Mars about every two years to get a better geological understanding of Earth's nearest planetary neighbor. It especially wants to learn if conditions ever existed that could have supported life. The latest in the series is the huge Mars Reconnaissance Orbiter, two stories tall and nearly 15 meters wide. It is closing in on the red planet after a seven month voyage from Earth.
The head of NASA's Mars exploration program, Douglas McCuistion says the effort now moves into a more intensive phase of investigation2.
"So this is a big mission for us," he said. "It's big in the strategic role in the Mars exploration program, it's the biggest orbiter sent to Mars in the past 30 years, carrying the most powerful suite3 of remote sensing instruments ever deployed4 to another planet."
Mars Reconnaissance Orbiter
NASA says the Mars Reconnaissance Orbiter will have better capabilities for understanding the red planet's surface, subsurface, and atmosphere than the three American and European satellites now orbiting, the two U.S. robotic rovers on the ground, or any previous mission.
"It's a weather satellite, it's a geological surveyor, it's a pathfinder for future missions," said NASA project scientist Richard Zurek. He says the new orbiter, known by its English initials MRO, carries six instruments. Some are designed to seek clues to the water most planetary scientists believe once flowed on Mars and is a key to life. They can identify water-related minerals and penetrate5 the ground about one kilometer to seek layers of rock, ice, and water if it is present.
"MRO follows the 'Follow the Water' program by combining global monitoring of the atmosphere and surface, by taking regional surveys of interesting areas, and then zooming6 in with very high resolution observations of the surface of the planet," he said. "Together, these data sets provide a new window into Mars' history and they will provide the best sites for future landers to go and to explore with some confidence that they are safe sites."
The Mars Reconnaissance Orbiter will return torrents7 of data about the red planet, more than all other Mars missions combined. It has five times better resolution over more area than its predecessor8 satellites. It can see things as small as a kitchen table, thanks to super-sharp cameras and a planned altitude 20 percent lower than previous spacecraft - about 300 kilometers.
"Every time we have increased our ability to resolve detail on the planet, we see new things, and we expect new surprises," Zurek said.
MRO pictured using its SHARAD radar9 to 'look' under surface of Mars
With so much power to collect information, NASA had to give the new spacecraft the means to send huge amounts of it back to Earth, quickly. So the orbiter carries the largest antenna10 ever sent to Mars, three meters in diameter, and a transmitter powered by large solar panels. The space agency's manager for the project, James Graf, says the data flow will be 10 times per minute higher than previous Mars orbiters.
"These other missions have been producing fantastic data, but they have been bringing the data back through, essentially11, a straw," he said. "What we are going to do is open the spigot and bring it back through a fire hose. That's crucial if you want to understand Mars. You want to increase the coverage12 and the resolution of your measurements, so you need that greater data."
Before the Mars Reconnaissance Orbiter can return any science, it must gradually adjust its extremely elongated13 35-hour orbit to a circular two-hour one using atmospheric14 friction15. This will take almost six months. Its primary data gathering16 phase is scheduled to last two years, but NASA says it is capable of going for up to a decade.
1 capabilities | |
n.能力( capability的名词复数 );可能;容量;[复数]潜在能力 | |
参考例句: |
|
|
2 investigation | |
n.调查,调查研究 | |
参考例句: |
|
|
3 suite | |
n.一套(家具);套房;随从人员 | |
参考例句: |
|
|
4 deployed | |
(尤指军事行动)使展开( deploy的过去式和过去分词 ); 施展; 部署; 有效地利用 | |
参考例句: |
|
|
5 penetrate | |
v.透(渗)入;刺入,刺穿;洞察,了解 | |
参考例句: |
|
|
6 zooming | |
adj.快速上升的v.(飞机、汽车等)急速移动( zoom的过去分词 );(价格、费用等)急升,猛涨 | |
参考例句: |
|
|
7 torrents | |
n.倾注;奔流( torrent的名词复数 );急流;爆发;连续不断 | |
参考例句: |
|
|
8 predecessor | |
n.前辈,前任 | |
参考例句: |
|
|
9 radar | |
n.雷达,无线电探测器 | |
参考例句: |
|
|
10 antenna | |
n.触角,触须;天线 | |
参考例句: |
|
|
11 essentially | |
adv.本质上,实质上,基本上 | |
参考例句: |
|
|
12 coverage | |
n.报导,保险范围,保险额,范围,覆盖 | |
参考例句: |
|
|
13 elongated | |
v.延长,加长( elongate的过去式和过去分词 ) | |
参考例句: |
|
|
14 atmospheric | |
adj.大气的,空气的;大气层的;大气所引起的 | |
参考例句: |
|
|
15 friction | |
n.摩擦,摩擦力 | |
参考例句: |
|
|
16 gathering | |
n.集会,聚会,聚集 | |
参考例句: |
|
|