【 以下文字转载自 NewExpress 讨论区 】
上周四（2月3日）发射升空的4-7批次星链卫星，49颗卫星中有40颗，已经或者即将再入大气层坠毁。

当天的猎鹰9号火箭发射正常，顺利将这批星链卫星送上近地点约210公里的预定轨道。接下来，每颗星链卫星都应该启动自带的氪离子推进器，自行抬升并部署到距离地面540公里的工作轨道。

然而，受上周五（2月4日）太阳活动带来的地磁暴影响，地球高层大气受热膨胀，导致高空大气密度增加，使得这批星链卫星所受空气阻力大增。据SpaceX透露的星载GPS数据，这批星链卫星所受阻力比以往增加了50%。

为应对这种突发状况，地面团队指挥这批卫星进入了安全模式。在这种模式下，星链卫星收缩成薄片状，以侧边缘向前飞行，以求最大程度减少所受的空气阻力。

然并卵，据SpaceX透露，受空气阻力大增的影响，这49颗星链卫星中有40颗最终没能退出安全模式，也就无法启动氪离子推进器抬升轨道。在距地面仅210公里的超低轨道上，如果没有动力来维持这一高度，卫星将很快再入大气层。

据Celestrak公布的追踪数据，这49颗星链卫星中有4颗已经坠毁，目前仍有20颗确认在轨，另有25颗状态不明。而按照SpaceX公布的消息，这批星链卫星中仅有9颗工作正常，其余40颗已经或者即将再入大气层。

按照SpaceX的说法，这些批脱轨卫星与其他卫星的碰撞风险为零（确实也没有其他卫星运行在这么低的轨道上），而按照设计，星链卫星再入大气层后会完全烧毁，不会有碎片落到地面。

一次性被太阳活动干掉这么多颗人造卫星，这在人类航天史上大概也是头一回吧……
--来自微水木3.5.11
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FROM 106.121.139.*

有个笑话是小偷偷了50万，第二天新闻里看到银行报失500万

【 在 AFP (afp) 的大作中提到: 】
: 【 以下文字转载自 NewExpress 讨论区 】
: 上周四（2月3日）发射升空的4-7批次星链卫星，49颗卫星中有40颗，已经或者即将再入大气层坠毁。
: 当天的猎鹰9号火箭发射正常，顺利将这批星链卫星送上近地点约210公里的预定轨道。接下来，每颗星链卫星都应该启动自带的氪离子推进器，自行抬升并部署到距离地面540公里的工作轨道。
: ...................
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FROM 27.91.71.*

FEBRUARY 8, 2022
GEOMAGNETIC STORM AND RECENTLY DEPLOYED STARLINK SATELLITES
On Thursday, February 3 at 1:13 p.m. EST, Falcon 9 launched 49 Starlink satellites to low Earth orbit from Launch Complex 39A (LC-39A) at Kennedy Space Center in Florida. Falcon 9’s second stage deployed the satellites into their intended orbit, with a perigee of approximately 210 kilometers above Earth, and each satellite achieved controlled flight.

SpaceX deploys its satellites into these lower obits so that in the very rare case any satellite does not pass initial system checkouts it will quickly be deorbited by atmospheric drag. While the low deployment altitude requires more capable satellites at a considerable cost to us, it’s the right thing to do to maintain a sustainable space environment.

Unfortunately, the satellites deployed on Thursday were significantly impacted by a geomagnetic storm on Friday. These storms cause the atmosphere to warm and atmospheric density at our low deployment altitudes to increase. In fact, onboard GPS suggests the escalation speed and severity of the storm caused atmospheric drag to increase up to 50 percent higher than during previous launches. The Starlink team commanded the satellites into a safe-mode where they would fly edge-on (like a sheet of paper) to minimize drag—to effectively “take cover from the storm”—and continued to work closely with the Space Force’s 18th Space Control Squadron and LeoLabs to provide updates on the satellites based on ground radars.

Preliminary analysis show the increased drag at the low altitudes prevented the satellites from leaving safe-mode to begin orbit raising maneuvers, and up to 40 of the satellites will reenter or already have reentered the Earth’s atmosphere. The deorbiting satellites pose zero collision risk with other satellites and by design demise upon atmospheric reentry—meaning no orbital debris is created and no satellite parts hit the ground. This unique situation demonstrates the great lengths the Starlink team has gone to ensure the system is on the leading edge of on-orbit debris mitigation.
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FROM 72.140.4.*

这是发射策略，210km让卫星自己爬升，如果卫星有问题就直接在低轨丢弃掉很快就能进入大气层烧掉不浪费轨道
  
【 在 LiYingReBa (LiYingReBa) 的大作中提到: 】
:  太偷懒了，打到210km就不管了
:  
:  【 在 AFP 的大作中提到: 】
:  :  
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FROM 111.201.49.*

反正地磁暴也不会说话，背锅最合适了。
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FROM 219.236.209.*