FAILURE: Shijian-18 - CZ-5 (Y2) - WSLC, LC101 - July 2, 2017 (11:23 UTC)

[Svetoslav]

This is part of the "rocket science"...

That's right On that count, 2017 is really *that* disappointing. What a horrible year. China's heavy lift carrier suffered a failure (which will probably delay Chang'e 5 to next year). There won't be a manned flight to space as SpaceX had their own delays, Blue Origin is not showing anything significant this year concerning New Shepard, Google Lunar XPrize suffered more delays (SpaceIL is delayed to 2018 at earliest and Team Indus has its own problems), and despite Richard Branson's optimism, we'll see if SpaceShip Two will start at least powered flights...

Let's hope that the small launcher industry will start more fluently, at least..

[Req]

and then there was some strange outgassing from the 1st stage that started from T+5 minutes or so. 

Agreed, I literally said "Hmm, that doesn't look good" aloud when that started up.

[Yellowstone10]

The vertical lines on the graph in that screenshot are at 250-second intervals, so it looks like the deviation began somewhere around the 400-second mark. That would put it before staging.

[RLA]

and then there was some strange outgassing from the 1st stage that started from T+5 minutes or so. 

Agreed, I literally said "Hmm, that doesn't look good" aloud when that started up.

Indeed, also as so far I can look back, the second stage did look normally. Does the LM-5 having an automatically shutdown system if something goes wrong and cannot being compromised anymore?

[gwiz]

Actually I think the core stage is probably where all the things started. The velocity curve seems to be dropping quickly by the time the 2nd stage was flying free. SEI-1 was almost 2 minutes late and then there was some strange outgassing from the 1st stage that started from T+5 minutes or so. 

Is the curve that starts to drop velocity or altitude?

[Phillip Clark]

This is part of the "rocket science"...

That's right On that count, 2017 is really *that* disappointing. What a horrible year. China's heavy lift carrier suffered a failure (which will probably delay Chang'e 5 to next year). There won't be a manned flight to space as SpaceX had their own delays, Blue Origin is not showing anything significant this year concerning New Shepard, Google Lunar XPrize suffered more delays (SpaceIL is delayed to 2018 at earliest and Team Indus has its own problems), and despite Richard Branson's optimism, we'll see if SpaceShip Two will start at least powered flights...
Let's hope that the small launcher industry will start more fluently, at least..

There *will* be manned flights because the Russians are still launching crews on the Soyuz-MS spacecraft.

[Galactic Penguin SST]

Does anyone have a cleaner feed of the launch (not the New China TV one which used their camera to film the LCC screen instead) through to 2nd stage flying?

[centaurinasa]

...Is the curve that starts to drop velocity or altitude?

I think it's the altitude...

https://twitter.com/search?src=typd&q=china%20spaceflight

[Satori]

China says launch of Long March-5 Y2 "unsuccessful".

[Katana]

T+11 minutes.

Stage 2 flame suddenly become asymmetrical here.
Both stage 1 and stage 2 have different fatal problem?

[Katana]

...Is the curve that starts to drop velocity or altitude?

I think it's the altitude...

https://twitter.com/search?src=typd&q=china%20spaceflight

The correct altitude during stage 2 burning and  coasting = GTO perigee = 185~200km
So the stage 2 started reentry over 100km at the moment ?

[frensel]

It is very likely that Chang'e 4 will be launched before Chang'e 5...

This is part of the "rocket science"...

That's right On that count, 2017 is really *that* disappointing. What a horrible year. China's heavy lift carrier suffered a failure (which will probably delay Chang'e 5 to next year). There won't be a manned flight to space as SpaceX had their own delays, Blue Origin is not showing anything significant this year concerning New Shepard, Google Lunar XPrize suffered more delays (SpaceIL is delayed to 2018 at earliest and Team Indus has its own problems), and despite Richard Branson's optimism, we'll see if SpaceShip Two will start at least powered flights...

Let's hope that the small launcher industry will start more fluently, at least..

[centaurinasa]

https://twitter.com/search?src=typd&q=china%20spaceflight
Seems that's a confirmation on 1st stage malfunction.....

[Req]

I suspected that was just turbopump exhaust but after watching again it appears that maybe it does develop into the big plume.  Either way, that feature was present before the big outgassing previously mentioned, which starts pretty bad but gets much worse over time.  By the time the footage cuts back to the reporters(on the feed I was watching) it almost looks like it's getting into the ballpark of CRS-7 style bad.

The reporters on the feed I was watching didn't really seem to know what they were talking about most of the time, but at one point they mentioned that the ascent camera is on the second stage, just for info.

Edit to add a shot showing the feature is clearly visible at booster separation.  Before that I can almost convince myself that I can see where it starts up(a lens flare conveniently moves to highlight it at the time I'm talking about), but it's too obscured to make a conclusion.

[Katana]

I suspected that was just turbopump exhaust but after watching again it appears that maybe it does develop into the big plume.  Either way, that feature was present before the big outgassing previously mentioned, which starts pretty bad but gets much worse over time.  By the time the footage cuts back to the reporters(on the feed I was watching) it almost looks like it's getting into the ballpark of CRS-7 style bad.

The reporters on the feed I was watching didn't really seem to know what they were talking about most of the time, but at one point they mentioned that the ascent camera is on the second stage, just for info.

TP exhaust turned into cold plume, TP failure?

[centaurinasa]

"The second launch of China's heavy-lift carrier rocket, the Long March-5, on Sunday was unsuccessful.
The rocket started to malfunction shortly after take-off, but the abnormality that led to the mission's failure was not immediately clear."

https://twitter.com/search?src=typd&q=china%20spaceflight

[centaurinasa]

[SmallKing]

There is rumor that one of YF77s lost its chamber pressure around 350 seconds after launch

[Yellowstone10]

I did a little analysis on the velocity curve from the now-infamous graph from that screenshot. Looks like the velocity curve starts to fall short around 360 seconds into flight, about 2 minutes before scheduled stage 1 cutoff and about 3.5 minutes before actual cutoff.

Edit - this seems basically consistent with the rumor SmallKing posted. If 1 of 2 YF77s failed, the remaining fuel should logically take about twice as long to consume, turning ~2 minutes burn remaining into ~4.

[Galactic Penguin SST]

There is rumor that one of YF77s lost its chamber pressure around 350 seconds after launch

I found a replay of the launch on a Chinese site - it looks like that the timing would fit perfectly with the outgassing event on the rocket's left side, which started at T+348 seconds (T+5:48).

Venting of the cold turbopump exhaust after the turbopump stopped would explain the venting as seen on the rocket cam.