随着航天活动的开展，空间碎片环境严重地威胁着在轨航天器的安全运行。
With the increase of the human aerospace activities, space debris environment is seriously threatening in-orbit spacecraft safe operation.
人类日益频繁而复杂的空间探索活动，使得空间飞行器在轨服务技术成为近年来研究热点。
On-orbit service techniques of spacecraft become the hot spot for the space explorations of human which are more and more frequent and complicated.
现代社会保障轨制树立之前，各类非营利组织就以各种方式从事社会救助等社会保障活动。
Before the modern social security system is set up, such social security activities as all kinds of nonprofit organization is engaged in society's succoring by various ways.
第二天安排了乘坐怀特山口及育空窄轨铁路公司的火车前往阿拉斯加斯卡圭的出游活动（依是否有合适的车次而定），或者您也可以就在白马市销磨这一日。
There is the option to go on a day trip to Skagway in Alaska with the White Pass & Yukon Railway Company (based on availability) or spend the day on your own in and around Whitehorse.
由活动台面将成材运至升降机的运料车上经逐层放置并下降至地轨运出。
The finished materials are transported to the material feeding wagon of the lift by the movable desktop, are placed layer by layer, and are lowered to the ground rail to be shipped out.
建议对其他部门，高速民用运输，爆音，臭氧环境，和火箭的单级入轨概念的超音速活动。
Advised on hypersonic activities for other divisions, the High Speed Civil Transport, sonic boom, ozone environment, and rocket SSTO concepts.
建议对其他部门，高速民用运输，爆音，臭氧环境，和火箭的单级入轨概念的超音速活动。
Advised on hypersonic activities for other divisions, the High Speed Civil Transport, sonic boom, ozone environment, and rocket SSTO concepts.
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