Author Topic: SpaceX Falcon Heavy : Arabsat 6A : LC-39A : April 11, 2019 - DISCUSSION (Read 308836 times)

fetcher · « **Reply #480 on:** 04/12/2019 12:16 am »

Quote from: flyright on 04/11/2019 11:29 pm

Quote from: The Vorlon on 04/11/2019 11:15 pm
Was anyone else having the SpaceX/Youtube feed crash as often as the Soviet Mars program?

It was constantly erroring out for me while I was using Firefox (which usually works just fine).
I switched to IE and it worked a lot better.

Streaming at 720p on a Roku, I saw maybe two instances of buffering (3-4 second pause), but nothing too bad, and no downgrade to a lower resolution. Youtube/Google have many thousands of of caching-server clusters deployed to data centers and ISPs all over the Internet, and try to route viewers through the "closest" one (with consideration for load-balancing and failover also) so the scope of any problems can be highly dependent on your geographic location and network provider.

OxCartMark · « **Reply #481 on:** 04/12/2019 12:33 am »

Quote from: ugordan on 04/12/2019 12:06 am

Quote from: OxCartMark on 04/11/2019 11:53 pm
Oh yea it was done in two stages.

I don't think it was done in two stages, from the moment of the green TEA/TEB flash seen at least on the side boosters, there was the usual 3-ish seconds before vehicle first motion, roughty 2 of those seconds with the ignited chambers. The apparent increase in flow can be due to either the engines ramping in power simultaneously or the initial water pool at the base of the flame trench got vaporized and thrown out.

It doesn't really make much sense doing it like in the first flight, I think they were simply careful and conservative with what the side-core vibrational loads would do to the center octaweb.

You might have been watching a different stream, a different camera angle than I was. Look at this, just before and just after T+1 ~~youtube.com/watch?v=n2xbZHlWTBc

_________

Going back to the apparent angularity of one of the landed boosters, look at the image below. If it was pinhole then I think the horizontal horizon near that booster would be angled as well but its horizontal and the booster is far from perpendicular to it.

_________

Take a look at the LZ campus. It looks as if there have been a lot of improvements (landscaping and infrustructure) done since I last looked in. Do we know about this or is this new? And what about the graphics on the concrete pads. I can't make out an X or a circle, they look like purple ink blots. What do you see in the ink blot?

obi-wan · « **Reply #482 on:** 04/12/2019 12:36 am »

Quote from: Lar on 04/12/2019 12:07 am

Quote from: ZachS09 on 04/11/2019 11:29 pm
Remind me if this question has been asked: were the fairings supposed to be recovered by Mr Steven for this launch?
No one is 100% certain what SpaceX planned initially... but Mr Steven wasn't even out there. Wisdom is that they will be fished out by other support vessels which traveled to their expected arrival location and were in place yesterday before the abort.

John said during the SpaceX broadcast that Go Searcher and Go Pursuit were downrange to pick up the fairings from the ocean.

ugordan · « **Reply #483 on:** 04/12/2019 12:38 am »

Quote from: OxCartMark on 04/12/2019 12:33 am

You might have been watching a different stream, a different camera angle than I was. Look at this, just before and just after T+1 ~~youtube.com/watch?v=n2xbZHlWTBc

I based my comment on that stream exactly. Well, the actual SpaceX (now archived) stream to be precise and not a 3rd party recording of it.

OxCartMark · « **Reply #484 on:** 04/12/2019 12:40 am »

Quote from: matthewkantar on 04/11/2019 11:55 pm

I noticed a very interesting and lovely phenomenon at MECO. As the boosters fall away from the core, they fall through their own exhaust plumes, so that a ring of fire seems to travel up the length of the boosters. When it passes over the boosters' cameras, it fuzzes them out for a second.

Perhaps not the cameras but the transmit antennas aren't doing much transmitting when exposed to fire? Thinking that its an ionizing gas that conducts electricity to an extent, similar to re-entry loss of communications. Guessing, not authoritative.

ugordan · « **Reply #485 on:** 04/12/2019 12:47 am »

Quote from: OxCartMark on 04/12/2019 12:40 am

Quote from: matthewkantar on 04/11/2019 11:55 pm
I noticed a very interesting and lovely phenomenon at MECO. As the boosters fall away from the core, they fall through their own exhaust plumes, so that a ring of fire seems to travel up the length of the boosters. When it passes over the boosters' cameras, it fuzzes them out for a second.

Perhaps not the cameras but the transmit antennas aren't doing much transmitting when exposed to fire? Thinking that its an ionizing gas that conducts electricity to an extent, similar to re-entry loss of communications. Guessing, not authoritative.

It's not the antennas. It's the cameras getting pummeled by exhaust like matthewkantar said, just like in the first FH launch. Except they were using CCD cameras back then as opposed to CMOS cameras this time so the rolling shutter effect was prominent here. Additional proof that it's not an antenna issue is the fact they edited the first webcast afterwards to fix some mess-ups, like showing the same booster camera on both views and they apparently replaced the right one with the onboard -recorded, 30 fps footage, as indicated by the appearance of timestamps in that video and the smoother framerate than the left booster.

ZachF · « **Reply #486 on:** 04/12/2019 12:50 am »

Been thinking about something.... I believe this FH flight is the first time that the mass of a delivered GTO payload exceeded the mass of the equipment that was expended to put it there!

sghill · « **Reply #487 on:** 04/12/2019 01:06 am »

Reverse angle I took at Playalinda beach.

P.s. sorry for the wrong video file earlier. $:-\$

ZachS09 · « **Reply #488 on:** 04/12/2019 01:09 am »

Another question to ask; this is about the engine ignition sequence.

For the test flight, the side boosters' engines began to ignite at T-5 seconds using a staggered sequence while the center core did the same at T-3 seconds.

It looked to me that for Arabsat 6A, all three boosters lit up at almost the same time. Why is that?

docmordrid · « **Reply #489 on:** 04/12/2019 01:10 am »

/sigh

Hate to bring this up but something's started online that the booster videos were the same, one channel copied to both frames.

Seems based on the demo mission webcast doing this and it being corrected in the YT file later.

ZachS09 · « **Reply #490 on:** 04/12/2019 01:11 am »

Actually, it looked to me that the booster cams were different this time. You can see that the booster headed to LZ-1 showed LZ-2 briefly during the landing burn.

docmordrid · « **Reply #491 on:** 04/12/2019 01:14 am »

Same here, but you know how this stuff goes...

Lars-J · « **Reply #492 on:** 04/12/2019 01:16 am »

Quote from: ZachS09 on 04/12/2019 01:09 am

For the test flight, the side boosters' engines began to ignite at T-5 seconds using a staggered sequence while the center core did the same at T-3 seconds.

It looked to me that for Arabsat 6A, all three boosters lit up at almost the same time. Why is that?

They were being extra cautious for the first FH launch. But apparently that slower staggered start sequence was not needed, because I agree it seemed much faster this time.

Herb Schaltegger · « **Reply #493 on:** 04/12/2019 01:17 am »

Quote from: OxCartMark on 04/12/2019 12:33 am

Take a look at the LZ campus. It looks as if there have been a lot of improvements (landscaping and infrustructure) done since I last looked in. Do we know about this or is this new? And what about the graphics on the concrete pads. I can't make out an X or a circle, they look like purple ink blots. What do you see in the ink blot?

As I was watching the live streams of the booster-cams, I thought it appeared that SpaceX hadn't bothered to repaint/refresh the pad surface(s) since the last use. However, as they touched down, the dark "blotches" seemed to recede in response to exhaust impingement. I wonder if SpaceX didn't simply spray the surface with water prior to the landings?

Lars-J · « **Reply #494 on:** 04/12/2019 01:18 am »

Quote from: matthewkantar on 04/11/2019 11:55 pm

I noticed a very interesting and lovely phenomenon at MECO. As the boosters fall away from the core, they fall through their own exhaust plumes, so that a ring of fire seems to travel up the length of the boosters. When it passes over the boosters' cameras, it fuzzes them out for a second.

The side boosters don't fall through their own exhaust plumes, they fall through the center core exhaust plume.

Lars-J · « **Reply #495 on:** 04/12/2019 01:20 am »

Quote from: Herb Schaltegger on 04/12/2019 01:17 am

Quote from: OxCartMark on 04/12/2019 12:33 am

Take a look at the LZ campus. It looks as if there have been a lot of improvements (landscaping and infrustructure) done since I last looked in. Do we know about this or is this new? And what about the graphics on the concrete pads. I can't make out an X or a circle, they look like purple ink blots. What do you see in the ink blot?

As I was watching the live streams of the booster-cams, I thought it appeared that SpaceX hadn't bothered to repaint/refresh the pad surface(s) since the last use. However, as they touched down, the dark "blotches" seemed to recede in response to exhaust impingement. I wonder if SpaceX didn't simply spray the surface with water prior to the landings?

Yes, it looked like they had watered the pad shortly before landing.

Lars-J · « **Reply #496 on:** 04/12/2019 01:21 am »

Quote from: ZachS09 on 04/12/2019 01:11 am

Actually, it looked to me that the booster cams were different this time. You can see that the booster headed to LZ-1 showed LZ-2 briefly during the landing burn.

Yep, they looked very similar at times (between boost-back and braking burn), but they were separate feeds. Very obvious during booster separation and landing.

RocketLover0119 · « **Reply #497 on:** 04/12/2019 01:22 am »

Sorry if it has been discussed already, but went back and watched the landings again, noticed the booster landing at LZ-2 is leaning by a pretty large margin post-landing, not sure if its the camera angle, or if its actually leaning.

ZachS09 · « **Reply #498 on:** 04/12/2019 01:24 am »

I think there was another member that stated that it was the camera angle.

aero1310 · « **Reply #499 on:** 04/12/2019 01:27 am »

I had the SpaceX Live stream and Everyday Astronaut Live stream up on separate monitors, had a third monitor but I have slow internet and didn't want to risk a buffer lol.

The multiple live stream view idea popped up last minute and worked out great. Sort of makes up for not being able to see it in person like I planned since I watched the first FH launch on my phone at work.

Oh and you don't get to hear the cool sonic boom on the SpaceX feed, so I turned down the SpaceX volume and cranked up the volume on EA feed lol.