Falcon 9 FT 2nd reuse launch - BulgariaSat 1 - LC-39A

[ecarfan]

My non-expert guess is that the rocket had significant lateral movement in the final few seconds of descent before touchdown. Not "nominal". But still a stage recovery success!

One cool thing I noted during the webcast: at stage separation, the camera at the top of the first stage looking up had a long continuous shot of the separation then second stage ignition and burn as the stages got farther apart. Awesome view! Seemed like a better view than in the past.

 

[hockeythug]

Congrats to everyone at SpaceX. Looking forward to see some footage in the coming week to fill in the dropped video feeds.

Right before the video cut on the 1st stage, I noticed the grid fins "on fire" (glowing red hot) like someone here on TMC had called out on a previous landing. We were paying attention to that based on the comment that this would be a high-energy landing approach.

Fancy new titanium grid fins next launch

 

[mdevp]

"Used almost all of the emergency crush core". Sorry new to SpaceX threads, what does this mean exactly?

 

[Grendal]

My non-expert guess is that the rocket had significant lateral movement in the final few seconds of descent before touchdown. Not "nominal". But still a stage recovery success!

Definitely. We saw ocean spray before the video feed was lost. Picture of the deck after the landing show a clear burn track and a pretty beat up booster. I thought this was supposed to be an easy one. Obviously, it was not. I wonder if SpaceX will actually reuse this booster for a third time.

"Used almost all of the emergency crush core". Sorry new to SpaceX threads, what does this mean exactly?

The landing legs have an aluminum honeycomb crush core. The leg cores can crush to act as a shock absorber in a hard landing. This was a three engine "hoverslam" very hard landing. The cores used most of the crush core which is why you see a noticeable tilt to the booster. This has happened a few other times with Thaicom 8 being the previous worst. That took all the pressure on only one leg and this looks to have affected two legs.

 

[ecarfan]

"Honey do I look crooked to you?"

"No dear, you're still beautiful."

 

[e-FTW]

Loss of video from the stage and ASDS made that a nerve wracking landing.

And the stage is more off center than usual. But no RUD.

Yes! I was on a conference call at the time, and I was the speaker. Ugh.
Standing in front of the TV with my wife, and we were both gesturing wildly in silence and going nuts waiting for the video feed to come back. Haha!

 

[e-FTW]

And the last image shown from the ASDS showed a spray of water off the port side (from the POV of the camera)

Am sure lots of folks thought that meant it was missing the mark. We sure thought so!

 

[Yuri_G]

And the last image shown from the ASDS showed a spray of water off the port side (from the POV of the camera) indicating, I think, that the stage was not descending straight down. That if reinforced by the position of the stage on the deck, which was quite near the starboard side. It's been awhile since a stage landed that far off center.

I think it was a tough landing.

I also noted that when the stage entry burn ended the cold gas thrusters came on almost immediately and the stage yawed quite a bit, as if a large correction was needed. Don't recall seeing that before, at least not so dramatically.

Bottom line is the stage landed and is intact!

Re-watching the landing that splash looks like a coincidental wave that crashed against the ASDS right as the feed froze. Still made the landing that much more suspenseful!

 

[Grendal]

Re-watching the landing that splash looks like a coincidental wave that crashed against the ASDS right as the feed froze. Still made the landing that much more suspenseful!

I'm not so sure about that. If you follow the burn streak across the ASDS, it started exactly where that splash occurred. If it was a coincidence, it was one heck of a coincidence. I really hope we see a video of this one. It's going to be an incredible landing if those scorch marks are any indication. Thaicom 8 still has the award for the largest tilt though. I also hope this booster is in good enough shape for one more launch. One reuse is amazing but two reuses is really proving the point.

 

[ecarfan]

Re-watching the landing that splash looks like a coincidental wave that crashed against the ASDS right as the feed froze

I don't think so. Look at the sea surface. Pretty calm. That spray appeared about just before the stage hit the deck.

Thanks to @Grendal for posting that image of the stage on the deck. Definitely tilted. And the two legs that shorter correspond with the angle of the stage. It hit hard.

"The Leaning Tower of BULGARIASAT-1".

 

[Yuri_G]

I don't think so. Look at the sea surface. Pretty calm. That spray appeared about just before the stage hit the deck.

Thanks to @Grendal for posting that image of the stage on the deck. Definitely tilted. And the two legs that shorter correspond with the angle of the stage. It hit hard.

"The Leaning Tower of BULGARIASAT-1".

After watching it a few more times, I may be inclined to agree with you guys. Can't wait for the video!

 

[Nikxice]

I really hope we see a video of this one. It's going to be an incredible landing if those scorch marks are any indication.

A clean landing video would be priceless! Not sure if there's any shadows, but the scorch marks at the 10 o'clock around the bullseye are fairly concentrated and then seem to fade a bit. Just a guess, but the "hoverslam" you alluded to earlier might have also produced a sizable lateral bounce or skip across the deck.

This landing brings to mind the expression that "almost only counts in horseshoes and hand grenades". SpaceX can add to that, starting with a landing outside the deck circle and then using almost all of their emergency crush core.

Looking back over the last 12 months of booster landing attempts, SpaceX is a proud 8 for 8.

 

[3Victoria]

The apparent lean may (partially?) due to the effect of the fish eye lens.

 

[e-FTW]

The apparent lean may (partially?) due to the effect of the fish eye lens.

Thought the same thing. I wonder!
Edit: watched it again, and the core looks curved in the video. So the lens may be exaggerating the lean. But it is leaning!

 

[Grendal]

Thought the same thing. I wonder!
Edit: watched it again, and the core looks curved in the video. So the lens may be exaggerating the lean. But it is leaning!

Some people on Reddit SpaceX and Facebook SpaceX photo shopped the fish eye lens effect back out and the core is leaning but nothing as bad as Thaicom 8. This is the perfect opportunity to use the Roomba robot grabber thing. In this instance it might be too big to slip under the booster. That is another video I'd love to see, the grabber robot holding onto the booster to hold it steady.

 

[Brovane]

Am sure lots of folks thought that meant it was missing the mark. We sure thought so!

My non-expert guess is that the rocket had significant lateral movement in the final few seconds of descent before touchdown. Not "nominal". But still a stage recovery success!

One cool thing I noted during the webcast: at stage separation, the camera at the top of the first stage looking up had a long continuous shot of the separation then second stage ignition and burn as the stages got farther apart. Awesome view! Seemed like a better view than in the past.

The lateral movement you see is intentional. During final descent in order to try and protect the Drone Ship, the rocket landing aim point is the Ocean right next to the Ship. This way in-case of failure the rocket plunges into the Ocean. At the last moment, the rocket then corrects to land on the drone ship. It was probably more apparent on this landing because of the use of 3 engines instead of one which makes the thrust more visible.

 

[MacGreiner]

Do they think they deliberately dropped the feed thinking it was going to be an aborted landing?

 

[Cosmacelf]

They haven't in the past...

 

[Krugerrand]

Do they think they deliberately dropped the feed thinking it was going to be an aborted landing?

No. Why would they? They've never tried to cover up or hide previous crash landings.

 

[scaesare]

The lateral movement you see is intentional. During final descent in order to try and protect the Drone Ship, the rocket landing aim point is the Ocean right next to the Ship. This way in-case of failure the rocket plunges into the Ocean. At the last moment, the rocket then corrects to land on the drone ship. It was probably more apparent on this landing because of the use of 3 engines instead of one which makes the thrust more visible.

Do you have some source for this?

Previous landings have had video that shows the rocket honing straight in on the bullseye where possible: