CBERS3失败原因找到--三级早关11秒，导致速度不够未入轨

http://www.spaceflight101.com/lo ... azil-and-china.html

The Long March 4B carrying CBERS-3 blasted off on time at 3:26 UTC on Monday from the Taiyuan Satellite Launch Center and performed a nominal initial ascent. Stages 1 and 2 performed as expected and the third stage also ignited on time and showed nominal performance. According to the National Institute for Space Research (INPE), Brazil, the Upper Stage shut down prematurely, about 11 seconds ahead of the planned time. The cause of the early shutdown of the upper stage is being investigated.

Cutting off 11 seconds too early resulted in a shortfall in velocity of roughly 0.25km/s which makes the difference between reaching a nearly circular orbit at 770 Kilometers and achieving a sub-orbital trajectory with a negative perigee. After third stage cutoff, the CBERS-3 satellite was released at the pre-programmed time of T+12.5 minutes.

The spacecraft then began its initial sequence, establishing communications with tracking stations, deploying its single solar array and starting to acquire three-axis control. According to INPE, the satellite remained in contact with ground stations for 15 minutes after separation and appeared to be functioning nominally.

After about half an hour of flight, the satellite and the CZ-4B upper stage re-entered to atmosphere – breaking up and impacting in Antarctica or the Southern Ocean.

一二级正常
三级点火也按时，根据巴西INPE机构说：上面级过早停火--比预定的时间早了11秒--然后开始调查此原因

提早关机的11秒，导致速度径直下降了大概0.25KM/S，这就跟要达到的接近770公里的圆轨道目标 造成了不同，而是到了一个亚轨道，且近地点也是错的。
第三级关闭过了一会儿后，卫星在预定时间T+12.5分钟释放

飞行器开始了他的最初设计，与地面站建立通信，施放单独的太阳板，开始进行三维操控，根据INPE说，卫星分离后  还能跟地面保持联络且运行正常15分钟

在飞行了半小时后，卫星与长征4B第三级重新进入大气。解体并撞击于 南极洲/南部海洋的地方http://www.spaceflight101.com/lo ... azil-and-china.html

The Long March 4B carrying CBERS-3 blasted off on time at 3:26 UTC on Monday from the Taiyuan Satellite Launch Center and performed a nominal initial ascent. Stages 1 and 2 performed as expected and the third stage also ignited on time and showed nominal performance. According to the National Institute for Space Research (INPE), Brazil, the Upper Stage shut down prematurely, about 11 seconds ahead of the planned time. The cause of the early shutdown of the upper stage is being investigated.

Cutting off 11 seconds too early resulted in a shortfall in velocity of roughly 0.25km/s which makes the difference between reaching a nearly circular orbit at 770 Kilometers and achieving a sub-orbital trajectory with a negative perigee. After third stage cutoff, the CBERS-3 satellite was released at the pre-programmed time of T+12.5 minutes.

The spacecraft then began its initial sequence, establishing communications with tracking stations, deploying its single solar array and starting to acquire three-axis control. According to INPE, the satellite remained in contact with ground stations for 15 minutes after separation and appeared to be functioning nominally.

After about half an hour of flight, the satellite and the CZ-4B upper stage re-entered to atmosphere – breaking up and impacting in Antarctica or the Southern Ocean.

一二级正常
三级点火也按时，根据巴西INPE机构说：上面级过早停火--比预定的时间早了11秒--然后开始调查此原因

提早关机的11秒，导致速度径直下降了大概0.25KM/S，这就跟要达到的接近770公里的圆轨道目标 造成了不同，而是到了一个亚轨道，且近地点也是错的。
第三级关闭过了一会儿后，卫星在预定时间T+12.5分钟释放

飞行器开始了他的最初设计，与地面站建立通信，施放单独的太阳板，开始进行三维操控，根据INPE说，卫星分离后  还能跟地面保持联络且运行正常15分钟

在飞行了半小时后，卫星与长征4B第三级重新进入大气。解体并撞击于 南极洲/南部海洋的地方