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一 | 　　成都8月21日电 (王利文罗梅歌)危旧房改造6万套、老旧小区新开工改造8000个、加装和更新电梯2.7万部、建成完整社区250个、改造城中村420个……8月21日，四川省人民政府新闻办公室在成都举行“万千气象看四川·起步奋进‘十五五’”系列主题新闻发布会，解读《四川省城市更新“十五五”规划》(下称《规划》)，从“好房子”到“好社区”，四川正把城市更新的答卷写在千家万户的获得感上。 Washington, Oct 12 (UNI) American space agency NASA says its recent attempt to deflect the path of an asteroid was successful, after its Dart probe struck an asteroid head-on.
Scientists have now confirmed the orbit of a 160m-wide space rock known as Dimorphos was altered when the Dart probe struck it head on last month.
Researchers came to the conclusion after making measurements using a range of space and Earth-based telescopes.
The mission was conceived to test a potential strategy to defend the Earth against threatening objects.
Dart's achievement proves such an idea would work, provided it was initiated early enough and the target wasn't overly massive.
"This mission shows that Nasa is trying to be ready for whatever the Universe throws at us," said agency administrator Bill Nelson.
"I believe that Nasa has proven that we are serious as a defender of the planet," he told reporters.
The space agency released a raft of data on Tuesday to support its assessment, including new pictures from the Hubble Space Telescope and from a small Italian spacecraft that stood off from the impact by about 50km (30 miles).
The Double Asteroid Redirection Test (Dart) took place some 11 million km (7 million miles) from Earth.
It saw the refrigerator-sized Nasa satellite drive straight into Dimorphos at 22,000km/h (14,000mph), destroying itself in the process.
The space rock orbits a much larger (780m wide; 2,550ft) object called Didymos. Before impact, the time taken for Dimorphos to make one circuit of its sibling was 11 hours and 55 minutes.
The telescope evidence now indicates this orbital period has been reduced to 11 hours and 23 minutes - a change of 32 minutes. This corresponds to Dimorphos moving closer into to Didymos by "tens of metres".
Nasa had defined a minimum successful period change of Dimorphos of 73 seconds or more. The results released on Tuesday show Dart surpassed this benchmark by more than 25 times.
"This is a 4 percent change in the orbital period of Dimorphos around Didymos. Dart just gave it a small nudge. But if you wanted to do this in the future, you'd want to do it years in advance," commented Nancy Chabot from the Johns Hopkins University Applied Physics Laboratory, which led the mission for Nasa.
"Warning time is really key here in order to enable this sort of asteroid deflection to be used in the future as part of a much larger planetary defence strategy."
Nasa's Dart programme scientist, Tom Statler, also had a word of caution about drawing too many conclusions from the experiment.
Asteroids came in many different guises, he said. Their compositions and constructions were diverse - something that was being emphasised every time a mission visited a new object.
"We should not be too eager to say one test on one asteroid tells us exactly how every other asteroid would behave in a similar situation," he stressed.
"But what we can do is use this test as an anchor point for our physics calculations in our simulations that tell us how different kinds of impacts in different situations should behave."
Four years from now, the European Space Agency (Esa) will have three spacecraft - collectively known as the Hera mission - at Didymos and Dimorphos to make follow-up studies.
UNI ING。

二 | 8月21日，四川省人民政府新闻办公室在成都举行“万千气象看四川·起步奋进‘十五五’”系列主题新闻发布会。四川发布供图　　“十四五”时期，四川城市更新已打下扎实根基：城镇化率提高至61.38%，开工改造城市危旧房5.3万套，改造城镇老旧小区2.99万个、城中村11.69万户，建设改造城市老旧地下管网5.3万公里。但当前仍有大量老旧小区、老旧街区、老旧厂区、城中村亟待改造提升。在此背景下，四川近日正式公布《规划》，全面打造“公园城市、安逸家园”。　　“城市的核心是人，城市更新的根本目的就是让民众生活得更舒心、更美好。”四川省住房和城乡建设厅副厅长朱莉在发布会上介绍，四川“十五五”期间将围绕“全面提升城市宜居水平”，在四个维度同步发力。　　在住房品质提升方面，“十五五”期间，四川将实施房屋品质提升工程，着力打造一批具有好地段、好配套、好物业、市场认可度高的“川居好房”，四川将实施城市危旧房改造6万套(间)。同时鼓励居民开展既有住房装修和局部升级改造，推广装配式装修、家居智能化、适老化、无障碍改造。　　在老旧小区改造方面，“十五五”期间，四川重点对建成满20年的住宅小区开展专项体检，全省新开工改造城镇老旧小区8000个，聚焦道路、供排水、燃气、通信、供电、消防、安防等基础设施改造，补增停车、充电、照明等设施，计划加装和更新电梯2.7万部。　　在完整社区建设方面，“十五五”期间，四川将建成完整社区250个，推动城市一刻钟便民生活圈扩围升级，建设改造社区基本公共服务设施、便民设施和配套基础设施，高标准建设一批社区综合服务中心，拓展养老、托育、助餐、就业、文体等功能。