-
(单词翻译:双击或拖选)
By David McAlary
The U.S. space agency is planning to conduct its first completely automated1 rendezvous2 in space Tuesday. In a test of new technology, a spacecraft is scheduled to be launched to track and meet an orbiting satellite with no human intervention3, a capability4 now enjoyed only by Russia.
Every U.S. rendezvous and docking in space over the last 40 years has required the guiding hands of astronauts. In contrast, Russian Soyuz crew vehicles and Progress cargo5 rockets routinely mate with the international space station automatically.
Now the U.S. space agency NASA is looking ahead to the time when its manned space shuttles stop visiting the station in six years and when robot supply ships are needed to service bases on the moon or Mars.
To demonstrate the technology to do this, an autonomous6 spacecraft named DART7 will be carried into space by a Pegasus rocket after both are dropped from the wing of a jet aircraft high over the Pacific Ocean. Once released, DART will use only its computers and sensors9 to rendezvous with a retired10 U.S. military communications satellite.
"DART is basically the technology to put two objects together in space," the manager of the DART project is James Snoddy. "What we've done with DART is we've basically created an eye, which we call an Advanced Video Guidance Sensor8, to be able to locate an object in space. We've also created what we call a brain, which has the ability to run all the guidance and control schemes in space without any human intervention."
The DART spacecraft is to guide itself to the vicinity of the target satellite with the help of a network of other satellites known as the Global Positioning System. The Global Positioning System relays data that the target satellite itself transmits about its location. As DART approaches the satellite, it own laser beam eye takes over the search. Mr. Snoddy says that once DART has located the satellite, it is to make a series of intricate maneuvers11 around it before closing in to a distance of five meters.
"We're basically pretty excited about being able to turn DART and let autopilot go and it's going to be an interesting mission where you really have no control of your mission once you let go of it, that's what the technology is all about," he said. "which one day this will allow for total autonomous operations in space."
The DART spacecraft will not dock during this demonstration12 because the target satellite was not designed for docking. But Mr. Snoddy says DART is precise enough to be able to attach to its target within a tolerance13 of only millimeters.
The technology will get its chance to prove itself in a series of actual dockings in two years. NASA and the U.S. military have joined forces to develop another autonomous spacecraft capable of refueling and servicing satellites. Beginning in late 2006, it will conduct several docking and refueling exercises and robotic transfers.
Such a craft could even be used to service the Hubble Space Telescope in 2007 or later now that NASA has decided14 not to send astronauts on such a mission.
Mr. Snoddy says even when a mission is manned, the technology would also be useful as an autopilot.
"Even the human eye has some error in it," he said. "An autopilot is a great thing to have to measure the distance and bring me precisely15 in to dock."
David McAlary , VOA News, Washington.
注释:
satellite 人造卫星
intervention 干预
dock 空间对接
astronaut 宇航员
demonstrate 证实
vicinity 附近地区
intricate 复杂的
maneuver 操纵
autopilot 自动驾驶仪
precise 精确的
Hubble Space Telescope 哈勃太空望远镜
1 automated | |
a.自动化的 | |
参考例句: |
|
|
2 rendezvous | |
n.约会,约会地点,汇合点;vi.汇合,集合;vt.使汇合,使在汇合地点相遇 | |
参考例句: |
|
|
3 intervention | |
n.介入,干涉,干预 | |
参考例句: |
|
|
4 capability | |
n.能力;才能;(pl)可发展的能力或特性等 | |
参考例句: |
|
|
5 cargo | |
n.(一只船或一架飞机运载的)货物 | |
参考例句: |
|
|
6 autonomous | |
adj.自治的;独立的 | |
参考例句: |
|
|
7 dart | |
v.猛冲,投掷;n.飞镖,猛冲 | |
参考例句: |
|
|
8 sensor | |
n.传感器,探测设备,感觉器(官) | |
参考例句: |
|
|
9 sensors | |
n.传感器,灵敏元件( sensor的名词复数 ) | |
参考例句: |
|
|
10 retired | |
adj.隐退的,退休的,退役的 | |
参考例句: |
|
|
11 maneuvers | |
n.策略,谋略,花招( maneuver的名词复数 ) | |
参考例句: |
|
|
12 demonstration | |
n.表明,示范,论证,示威 | |
参考例句: |
|
|
13 tolerance | |
n.宽容;容忍,忍受;耐药力;公差 | |
参考例句: |
|
|
14 decided | |
adj.决定了的,坚决的;明显的,明确的 | |
参考例句: |
|
|
15 precisely | |
adv.恰好,正好,精确地,细致地 | |
参考例句: |
|
|