SpaceX FH : Falcon Heavy Demo : Feb 6, 2018 : Discussion Thread 2

[RocketLover0119]

I think june.

when is the next FH flight scheduled?

[Zipi]

From this video you can see a glimpse about the center core splashing down near OCISLY after 1:11:

[Comga]

when is the next FH flight scheduled?

See the Manifest thread
It says NET June for STP-2

[OnWithTheShow]

Yes, the video clearly shows the stage coming in at an angle and overshooting the ASDS. For those who missed it, the great "overshoot vs. undershoot" debate started here:

https://forum.nasaspaceflight.com/index.php?topic=44778.msg1788585#msg1788585

...and lasted several pages, so is worth revisiting in light of the new video. Hopefully all debaters will view the video and some will see the error of their ways.  Meanwhile, you may bask in the knowledge that you were indeed correct. 

stirring

But what if RTLS cores undershoot and ballistic ASDS cores overshoot?

/stirring

[Lar]

Don't be a pot stirrer!

[Kabloona]

Yes, the video clearly shows the stage coming in at an angle and overshooting the ASDS. For those who missed it, the great "overshoot vs. undershoot" debate started here:

https://forum.nasaspaceflight.com/index.php?topic=44778.msg1788585#msg1788585

...and lasted several pages, so is worth revisiting in light of the new video. Hopefully all debaters will view the video and some will see the error of their ways.  Meanwhile, you may bask in the knowledge that you were indeed correct. 

stirring

But what if RTLS cores undershoot and ballistic ASDS cores overshoot?

/stirring

It being a slow day, I'll take the bait and suggest it makes no sense to have two different terminal guidance algorithms.

SpaceX was required by the Range to demonstrate landing accuracy on the ASDS before they were allowed to attempt RTLS landings, and I find it unlikely that the Range would approve an RTLS attempt using a different algorithm than was demo'd on the ASDS.

I also find it unlikely that SpaceX would introduce the unnecessary complexity of using two different terminal guidance algorithms.

Now, are we allowed to hope one of those RTLS cores runs out of TEA/TEB, or would that be wrong? 

[biosehnsucht]

Legs not deploying likely not "an additional failure" but merely a result of going too damn fast and thus either they failed to deploy because that was based on some kind of timing as a function of elapsed mission time, or because there was so little time between the deployment altitude / time to surface that they never got a chance to move before splashing.

[Jcc]

I guess this footage should end the debate of whether or not a stage will overshoot or undershoot it’s landing spot if the engines fail to light for the landing burn. (But who am I kidding, of course it won’t)

You actually convinced me half way through but was having too much fun to stop.

[SkyRate]

Even if there is no speed sanity check in the leg extension trigger and it considers just altitude or time-to-zero-altitude, I suspect that the actuators were just not strong enough to push the legs down.
If, say,  the speed was 3 times higher than normal then the aerodynamic forces on the legs were 9 times higher.
You just don't overdesign things to that degree on a rocket.

[NGCHunter]

Here are some stacked images I made from the Falcon Heavy launch using my telescopic tracking footage.  I stacked about 5~6 consecutive frames.  In the case of the boostback image, I had to layer two stacks; one aligned on the boosters, the other aligned on the core stage due to the differential motion even over 5 frames.

http://h.dropcanvas.com/t7z6r/falconheavy6stackedframes17x20.jpg

http://h.dropcanvas.com/t7z6r/fhboostbacklayering3final.jpg

I think it's the first time I've done image stacking for launch photos, but it came out pretty well.

[Space Ghost 1962]

Very good work. Not easy to get such high detail and saturated color imagery. Or the detail on the booster's flip and ignition. Can even notice some TO hints in the plumes.

Thank you for sharing your work.

[RocketLover0119]

Caught this during Gwynne Shotwell's TED presentation, FH being lifted up before being placed on the TEL.

[vaporcobra]

Caught this during Gwynne Shotwell's TED presentation, FH being lifted up before being placed on the TEL.

[BradyKenniston]

Was it known that the Falcon Heavy center core engines were reused? Hans Koenigsmann mentions it in his NEAF talk and I don’t recall hearing about that before.

https://www.youtube.com/watch?v=Va-rXO7kI-8?t=14799

4:06:39 into the video if that doesn't take you right to the point where Hans mentions it.

[vaporcobra]

Was it known that the Falcon Heavy center core engines were reused? Hans Koenigsmann mentions it in his NEAF talk and I don’t recall hearing about that before.

https://www.youtube.com/watch?v=Va-rXO7kI-8?t=14799

4:06:39 into the video if that doesn't take you right to the point where Hans mentions it.

99% sure it's new info.

[e of pi]

Was it known that the Falcon Heavy center core engines were reused? Hans Koenigsmann mentions it in his NEAF talk and I don’t recall hearing about that before.

https://www.youtube.com/watch?v=Va-rXO7kI-8?t=14799

4:06:39 into the video if that doesn't take you right to the point where Hans mentions it.

99% sure it's new info.

Perhaps the JCSAT-14 or -16 engine set? The timing would be about right, they flew around the same time as the cores which became side cores used for FH.

[vaporcobra]

Was it known that the Falcon Heavy center core engines were reused? Hans Koenigsmann mentions it in his NEAF talk and I don’t recall hearing about that before.

https://www.youtube.com/watch?v=Va-rXO7kI-8?t=14799

4:06:39 into the video if that doesn't take you right to the point where Hans mentions it.

99% sure it's new info.

Perhaps the JCSAT-14 or -16 engine set? The timing would be about right, they flew around the same time as the side

This photo of the JCSAT-16 booster in March 2017 suggests that it was probably scavenged for the center core's Merlins. As far as I can tell, that booster has no engines installed.

[Nomadd]

 Any particular reason to think the engines were all from one core?

[vaporcobra]

Any particular reason to think the engines were all from one core?

Same chain of custody, so to speak. Work with an individual recovered engine would likely be more relevant for the refurbishment of others if all engines experienced (roughly) the same conditions during their first flight.

I'm very open to being wrong, though. Just seems intuitive to me that you would want to use engines from the same flight if you were planning on reusing a whole bunch.

[Cheapchips]

Not sure if anyone from SX mentioned this before, Hans confirmed at NEAF that the Roadster was all a bit of a rush.  They didn't have time/resource to do more than test cameras and ensure they had a working feed.