China’s SJ-21 ‘tugs’ dead satellite out of GEO belt Trackers


Date:2022-01-27 Source:未知 By:admin Viewed:

"I think there are more questions than answers right now when it comes to SJ-21," Todd Harrison, director of CSIS's Aerospace Project, told Breaking Defense.
on January 26, 2022

A virtual dashboard created in partnership by CSIS, the Secure World Foundation and the University of Texas at Austin allows users to track real-time and predicted movements of satellites and space junk. (Screengrab
由美国战略与国际问题研究中心(CSIS)、安全世界基金会和得克萨斯大学奥斯汀分校合作创建的虚拟仪表盘(A virtual dashboard)允许用户跟踪卫星和太空垃圾的实时和预测运动。(satellitedashboard.org截图)
Updated Jan. 26, 2022 at 5:00 pm ET to include latest tracking data showing the coupled SJ-21 and Compass G2 separating.
美国东部时间2022年1月26日下午5:00更新,包括显示对接的SJ-21和Compass G2的最新跟踪数据。
WASHINGTON: China’s SJ-21 satellite now “appears to be functioning as a space tug,” pulling a dead CompassG2, or Beidou, navigation satellite out of the way of other satellites operating in the heavily populated Geosynchronous Orbit, according to a new analysis by commercial space monitoring firm ExoAnalytic Solutions.
华盛顿:根据商业空间监测公司ExoAnalysical Solutions的一项新分析,中国的SJ-21卫星现在“似乎正在发挥太空拖船的作用”,将一颗已失效的Compass G2或北斗(Beidou)从拥挤的地球同步轨道上运行的其他卫星中拖离。
The observations were reported today by Brien Flewelling, who serves as the firm’s chief architect for space situational awareness (SSA), during a webinar hosted by the Center for Strategic and International Studies (CSIS).
在今天战略与国际研究中心(CSIS)主办的网络研讨会上,该公司空间态势感知(SSA)首席架构师布莱恩·弗莱韦林(Brien Flewelling)报告了这些观察结果。
According to Flewelling’s video presentation, the SJ-21 on Jan. 22 went “missing” from its orbital slot for a few hours, after performing what are known as “close proximity operations,” moving closer and closer around the Compass G2. The “gap” in observations was caused by the fact that when it then docked with the defunct satellite, it was daytime — when telescopes cannot image. ExoAnalytics tracked it down after it had subsequently performed “a large maneuver” pulling the dead satellite out of GEO.
根据弗莱韦林的视频演示,SJ-21于1月22日在其轨道位置“失踪”了几个小时,在执行了所谓的“近距离操作”之后,在 Compass G2周围越来越近。观测中的“差距”是由于当它与失效的卫星对接时,是白天——望远镜无法成像。在随后执行“大机动”将生效卫星从地球同步轨道(GEO)拖出后ExoAnalytics对其进行了追踪。
“We continue to track SJ-21 and monitor it for conjunctions with all known space objects. The ability to maintain custody of SJ-21 after this large daytime maneuver is an important and unique capability of Exo’s commercial SSA network,” the video reported.
Space Command, which via the 18th Space Control Squadron monitors space objects, did not respond to a request for comment by press time.
The SJ-21 is the same satellite that this past November caused a bit of a kerfuffle when the 18th Space Squadron reported that it was moving around either a sub-satellite or its kick motor (AKM) in a way that suggested Beijing was testing how to spoof space monitoring networks.
SJ-21就是去年11月引起一些混乱的卫星,去年11月,当第18太空中队报告说它正在一颗子卫星或其加速引擎 (AKM) 周围移动时,这表明北京正在测试如何欺骗空间监控网络。
EXCLUSIVE: US, China, Russia sats buzzing, spoofing, spying on each other
The Chinese satellite’s maneuvers are consistent with the capabilities needed to conduct On-Orbit Servicing, Assembly, and Manufacturing (OSAM) — capabilities that the US and Europe also are pursuing.
Beijing has a national goal to develop OSAM capabilities, according to a Dec. 13, 2021, study by Air University’s China Aerospace Studies Institute.
“An investigation into China’s stated OSAM goals and activities helps contextualize SJ-21 as a satellite to further test on-orbit debris mitigation technologies. On-orbit services to mitigate debris come in many forms, such as through refueling or relocation, and could eventually support a range of customers, including Chinese military, government and emerging commercial players, which would be consistent with OSAM activities globally,” wrote author Kristin Burke.
“对中国公开的OSAM目标和活动的调查有助于将SJ-21作为一颗卫星,进一步测试在轨碎片缓解技术。缓解碎片的在轨服务有多种形式,例如通过加注燃料或重新安置,最终可能支持包括中国军方在内的一系列客户。”作者克里斯汀·伯克(Kristin Burke)写道。
Led by NASA, the Trump administration in November 2020 launched a US national OSAM initiative, and since then the Defense Department has been pursuing a number of technology development projects.
In particular, the Air Force Research Laboratory is working closely with Northrop Grumman subsidiary SpaceLogistics on research projects designed to build OSAM capabilities. SpaceLogistics in April 2021 successfully docked its second Mission Extension Vehicle (MEV) with an Intelsat satellite to provide extra power to keep the communications satellite functional.
特别是,美国空军研究实验室正在与诺斯罗普·格鲁曼公司的子公司空间后勤技术公司(SpaceLogistics)密切合作,开展旨在建立 OSAM能力的研究项目。空间后勤技术公司(SpaceLogistics)于2021年4月成功地将其第二个任务扩展飞行器 (MEV) 与一颗国际通信卫星对接,以提供额外的动力来保持通信卫星的正常运行。
However, the SJ-21’s current orbit is “unusual” if the aim is to dispose of the defunct Compass G2 in what is known as the “graveyard” orbit, said Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics who keeps tabs on satellites. The Chinese satellite’s orbit is highly elliptical, he said, ranging from 36,076 km in altitude to 38,886 km, “so 290 x 3,100 km above GEO.”
然而,哈佛-史密森尼天体物理学中心的天体物理学家乔纳森·麦克道尔 (Jonathan McDowell) 表示,如果目标是在所谓的“墓地轨道“上处理已失效的Compass G2,那么SJ-21目前的轨道是“不寻常的”。 他说,这颗中国卫星的轨道是高度椭圆形的,高度从 36,076公里到38,886公里不等,“因此在GEO上方290 x 3,100公里。”
Graveyard orbit is usually defined as 300 kilometers above GEO, which is at about 36,000 km.
“Usually GEO graveyard raising is done more symmetrically,” McDowell explained.
In an email to Breaking Defense this afternoon, Flewelling said the latest tracking data gathered earlier today from ExoAnalytic’s telescopes show the SJ-21 separating from the Compass G2, leaving the latter in the eccentric “super-graveyard drift orbit.” SJ-21 now has moved back to a near-GEO orbit.
弗莱韦林在今天下午发给《突破防御》的电子邮件中说,今天早些时候从ExoAnalytical望远镜收集的最新跟踪数据显示,SJ-21与Compass G2分离,使后者处于偏心的“超级墓地漂移轨道”后SJ-21现在已经返回近地球轨道。
Todd Harrison, director of CSIS’s Aerospace Project, told Breaking Defense that SJ-21’s movements have prompted “more questions than answers.”
“What we know for sure is what we can observe by its actions in space — the intent behind it and what China plans to do with this technology is a more subjective assessment,” he said.
He added that the Chinese sat “clearly is capable of close proximity operations, docking, and maneuver, much like Northrop’s MEV satellites. Beyond that, we will have to wait and see how they continue to use this satellite and others that come after it.”
Aaron Bateman, a former Air Force intelligence officer now at John Hopkins University, said that it is high time for nations to improve transparency about such satellite maneuvers.
“This is more evidence that there needs to be a greater effort to establish confidence-building measures for space, with a special focus on GEO,” he told Breaking Defense. “Now is the time for the US to work with China, Russia, and other countries to establish norms of behavior aimed at reducing the risk of escalation due to uncoordinated and unannounced close approaches in the GEO belt.”
“这更多的证据表明,需要付出更大的努力来建立太空信任措施,特别是关注GEO,”他告诉《突破防御》(Breaking Defense)。“现在是美国与中国、俄罗斯和其他国家合作建立行为准则的时候了,目的是减少由于地球同步轨道(GEO)带内不协调和未宣布的近距离接触而升级的风险。”
With the aim of spurring improved transparency about close approaches on orbit, CSIS, the Secure World Foundation and the University of Texas at Austin today launched a new web-based project to track real-time and predicted movements of satellites and space junk.
“The Satellite Dashboard is a web-based tool that will collate and analyze” SSA data and “present it in an accessible format, while also providing a queuing function for further technical analysis,” the new website explains. The site “collates data from multiple sources, including publicly-available data provided by the U.S. military, commercial SSA providers, and data provided by international, scientific, and academic sources.”
新网站解释说:“卫星仪表盘(The Satellite Dashboard)是一个基于网络的工具,它将整理和分析“SSA数据,并“以可访问的格式呈现数据,同时还为进一步的技术分析提供排队功能。”。该网站“整理来自多个来源的数据,包括美国军方、商业SSA提供商提供的公开数据,以及国际、科学和学术来源提供的数据。”

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