China's Space Program News Thread

[Quickie]

From Internet chatter, it seems that the cryogenic second-stage YF-75D engines prematurely shut down, leading to a late separation of the second stage from the first and the eventual inability to reach the designated orbit.

Interestingly, a similar incident occurred during the maiden launch of the LM-5 in November 2016, in which the (supposed) second stage put the YZ-2 third stage and its payload on an incorrect orbit that was later rectified using the YZ-2. These two anomalies could be related and warrant further investigation.

Better now than during the upcoming Chang'e-5 launch.

China space is at healthy state. They are collecting lots of datas right now on the latest failed launch. At least it didn't explode some other programs out there. This seems to be a glitch on the second stage, but nothing that China can't resolve and try again soon.

Could the satellite be saved this time around?

If it's caused by the same bug, it's unfortunate the problem wasn't nipped in the bud the first time they have the opportunity.

 

[SinoSoldier]

Could the satellite be saved this time around?

If it's caused by the same bug, it's unfortunate the problem wasn't nipped in the bud the first time they have the opportunity.

My guess is that since the third stage successfully corrected the issue brought about by the second stage during the maiden launch, they overlooked the potential severity of the issue; things like this have happened to other space agencies in the past.

The satellite could've been saved only if it had been placed in a parking orbit with the YZ-2 third stage attached. If the Hohmann transfer to GEO had required the SJ-18 satellite to expend its own fuel, a satellite refueling spacecraft (like the one test-launched by the Long March 7 on its first flight) would be very useful in extending its compromised lifespan.

 

[Lethe]

That what i said earlier. China needs to ramp up spending, because It is behind of Spacex. And the gap is widening. I don't understand why the budget of Chinese Space Agency is even lower than Japanese one.

The gap is not widening. China is already looking at reusable rocket technology. The US (and others) continue to advance, but China is advancing more rapidly and closing the gap. Of course other nations are not going to stand still while they wait for China to catch up, but new milestones do not alter the basic trajectory of convergence.

 

[PanAsian]

Layperson question here, can the satellite be recovered if it cannot be put in orbit and is not destroyed somehow? Has any space program ever recovered a satellite in such circumstances (not in orbit but not destroyed either)? Or is it just an additional piece of space junk?

 

[KIENCHIN]

Layperson question here, can the satellite be recovered if it cannot be put in orbit and is not destroyed somehow? Has any space program ever recovered a satellite in such circumstances (not in orbit but not destroyed either)? Or is it just an additional piece of space junk?

The space shuttle did recover a satellite, repaired it and put it in the right orbit from memory.

 

[antiterror13]

I do hope the satellite Shijian-18 could be saved, even reduced life. BTW it is an experimental Geostationary Communications Satellite. "Weighing in at over seven metric tons, Shijian-18 will be the heaviest Geostationary Satellite as of its June 2017 launch, surpassing the previous record holder TerreStar-1 (6,902kg)"

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So, the positive side of this partial failure is Chinese Space Agency will get stronger and more fund available ... even a few may get sacked

 

[SinoSoldier]

Update: possible fuel leak during the last 3 minutes of the first stage's flight might have caused one of the YF-77 engines to prematurely shut down.

Second anomaly occurred soon after when two YF-75D engines of the second stage failed to ignite. The LV + sat weren't able to reach a parking orbit following a massive loss of velocity.

 

[antiterror13]

Update: possible fuel leak during the last 3 minutes of the first stage's flight might have caused one of the YF-77 engines to prematurely shut down.

Second anomaly occurred soon after when two YF-75D engines of the second stage failed to ignite. The LV + sat weren't able to reach a parking orbit following a massive loss of velocity.

so, would the satellite be saved?

 

[jobjed]

so, would the satellite be saved?

I think it's already ash by now.

 

[Richard Santos]

Did the second stage fail to ignite?

NASA seem to believe the second stage did ignite approximately 1 minute later than expected, and then shut down prematurely after burning for just a minute.

It's not clear why the second stage ignited late. It seems possible to me that the reason is the first stage did not fail completely, but instead failed only partially and was commanded burned longer but at reduced rate to attempt to compensate for the fault. Or maybe the stack was coasting because initial ignition of second stage did fail, but some workaround was found either by flight control system, or more likely ground control given the length of delay, to successfully ignite the stage a minute later

It's also not clear why the second stage shutdown prematurely. It could be the second stage also had a serious fault. Or it could be that The stage was shut down because it was no longer possible to achieve orbit or avoid premature re entry.