美宇航局火星降落实验获成功
[font=Verdana, Arial, Tahoma][size=14px][b]A US space agency (Nasa) experiment on Saturday to test future Mars landing technologies proved largely successful.[/b][/size][/font][font=Verdana, Arial, Tahoma][size=14px][b]美国宇航局上周六进行了一次未来式火星降落实验，结果大获成功。[/b][/size][/font]
[font=Verdana, Arial, Tahoma][size=14px][img=304,405]http://www.enread.com/upimg/allimg/140630/1_140630075508_1.jpg[/img]
[color=#0000FF]Artist's impression: A rocket motor was used to shoot the vehicle up through the stratosphere[/color]
[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]A flying saucer-shaped vehicle was sent high into the atmosphere via a balloon to trial a new type of[b]
parachute（降落伞）[/b]
and an inflatable Kevlar ring that could help slow down a [url=http://www.enread.com/news/sciandtech/97207.html]spacecraft[/url] as it approaches the Red Planet's surface.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]All of the equipment appeared to work apart from the parachute, which failed to deploy fully.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]The experiment was sent up from Hawaii.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]Nasa hopes the lessons learned will enable it put heavier payloads on Mars in the decades ahead.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]The current limit is about one-and-a-half tonnes.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]If humans are ever to go to the planet, this mass capability will have to rise to well beyond 10 tonnes.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]Saturday's test vehicle, known as the Low Density Supersonic Decelerator (LDSD), ditched in the Pacific after its flight.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]Teams were despatched to try to locate the demonstrator so that its data recorder could be recovered.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]This will give engineers the most detailed information on what precisely happened during the experiment.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]Video cameras on the ground and on the LDSD captured most of the [url=http://www.enread.com/news/sciandtech/97207.html]flight[/url].[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]The helium balloon was launched from the US Navy's Pacific Missile Range Facility in Kauai at just after 08:40 local time. [/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]It took over two hours to raise the saucer-shaped vehicle to roughly 35km, whereupon it was released.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]A rocket motor then kicked the LDSD on up through the stratosphere to above 50km, and to a velocity of Mach 4 (four times the speed of sound) - the sort of conditions a spacecraft approaching Mars might encounter.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]As the vehicle began to slow, it deployed the first of its two new atmospheric braking systems.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]This first system was a 6m inflatable "doughnut". It enlarged the LDSD's girth and so will have slowed the saucer further by increasing the amount of drag it experienced.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]The second braking system, however, did not come out properly.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]Upward-looking video showed the 30m-diameter supersonic parachute failing to unfurl correctly.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px][url=http://www.enread.com/news/sciandtech/97207.html]Nasa[/url] engineers said before the test that they would gather valuable data whether the technologies on the LDSD worked properly or not.[/size][/font]
[font=Verdana, Arial, Tahoma][size=14px]The project hopes to return to Hawaii next year to conduct two further test flights.[/size][/font]
[size=14px]更多[/size][size=14px][b][size=5][color=#963c3c][url=http://www.enread.com/news/index.html]英语新闻[/url][/color][/size][/b][/size]
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