Shijian 18 (Long March 5 YZ-2) 2017/07/02 21:20

[RedKraken]

Long March 5 launches out of Wenchang in about 32hrs time.

http://rocketwatch.yasiu.pl/?

http://forum.nasaspaceflight.com/index.php?topic=42798.0

http://spaceflight101.com/long-march-5-shijian-18/shijian-18/

On Pad, 880t.

Payload : 25t LEO, 14t GTO, 8,2t TLI.

Kerolox boosters, hydrolox core.

YZ-2 model has a third stage UDMH/NTO 

Maiden launch was 6 months ago.

This is the 2nd launch.

3rd launch in November 2017 is the lunar sample return mission Chang'e5

https://en.wikipedia.org/wiki/Long_March_5

http://spaceflight101.com/spacerockets/long-march-5/

[Kryten]

Launch is in about ten minutes.

 The payload is a large communications sat based on the new DFH-5 bus. At just over seven metric tons it's the largest ever produced in China by a big margin, and should be the largest ever by a slim margin. It also includes a quantum comms experiment and new large ion thrusters for station-keeping.

Edited July 2, 2017 by Kryten

[Kryten]

http://news.xinhuanet.com/politics/2017-07/02/c_1121250175.htm

Quote

　　Xinhua News Agency News: July 23, 19:23, China in China Wenchang space launch site organized the implementation of the Long March five remote two rocket mission, rocket flight anomalies, launch mission failure. Follow-up will organize experts to investigate the cause of the failure.

 

[Gaarst]

Yep launch failure.

Folks as NasaSpaceflight say it may have something to do with the second stage. Although the rocket seems off its planned trajectory as early as the first stage burn with 1st stage shutdown occurring over one minute later than planned.

Discussion: http://forum.nasaspaceflight.com/index.php?topic=42798.100

[RedKraken]

Yep mission failure.

 

Here is the launch replay : cuts at 4:42

 

Oh man.....

[RedKraken]

Booster sep ok at 175s.

Deviations from flight path could have happened as early as 400s.

stage 1 sep ok at 465s? looks like it happened at 570s. Wow I wonder what went wrong.

stage 2 takes a dive back into the atmosphere

Launch time line was supposed to be :

T+0s      Liftoff
T+17s    Pitch program initiated
T+174s  Boosters separation
T+285s  Fairing separation
T+465s  MECO/1st stage separation/2nd stage ignition
T+753s  SECO-1
T+1355s SEI-2
T+1714s SECO-2
T+1810s Spacecraft separation

[Gaarst]

2 hours ago, RedKraken said:

It does look like a serious lack of thrust midway through the 1st stage burn.

1 hour ago, RedKraken said:

Booster sep ok at 175s.

Deviations from flight path could have happened as early as 400s.

stage 1 sep ok at 465s? looks like it happened at 570s. Wow I wonder what went wrong.

stage 2 takes a dive back into the atmosphere

Yep something definitely happened near 400 secs, trajectory was correct before that. First stage is powered by 2 engines, I'd bet on one engine failure: the stage still continued to burn after loss of thrust (stage was still functional) and it did burn longer to try to compensate (so probably not a leak). Edit: it could have been a leak related to the engine itself, I don't see why a single engine would keep running if the propellant/oxidiser tank was leaking and losing pressure.

 

Here's how I read the graph:

 

 

Edited July 2, 2017 by Gaarst

[RedKraken]

cool.....

Lots of interest in the 1st stage outgassing event.....big plume got worse thru the burn.

One of the YF-77 hydrolox engines fail?

ahhh....NSF reports

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

 

 

Edited July 2, 2017 by RedKraken
nsf rumour

[tater]

Too bad, China.

Space is, as they say, hard. Everyone has bad launches from time to time. 

On the on-board camera, what was that flapping around near the left strap on booster in the frame?

Edited July 2, 2017 by tater

[Gaarst]

Got a replay of the launch:

https://www.youtube.com/watch?v=LyKXiXTRAuI

Big outgassing at T+5:46 (around 10:50 on the video). As people on NSF said, it could be turbopump venting cold propellant after an engine shutdown, and it coincides with the point the actual flight profile starts diverging with the planned one.

18 minutes ago, tater said:

On the on-board camera, what was that flapping around near the left strap on booster in the frame?

Where/when do you see this?

[tater]

Maybe 120 seconds plus into the launch, from the on board cam looking down. Probably just insulation or something.

Flaps for quite a while.

[Gaarst]

3 minutes ago, tater said:

Maybe 120 seconds plus into the launch, from the on board cam looking down. Probably just insulation or something.

Flaps for quite a while.

I see what you mean. Yeah it's probably insulation flying off, it happens on the right side booster too and I wouldn't be suprised if it happened on the other two boosters as well.

I don't think it's related to the failure.

[tater]

Yeah, all the flapping caught my eye.

[tater]

1 hour ago, Gaarst said:

Got a replay of the launch:

https://www.youtube.com/watch?v=LyKXiXTRAuI

 

9:09 into the video (they took a video of a screen? (pretty lousy) you can see that the animation shows only one engine running. Cruddy animation, or telling us something?