SpaceX Falcon 9 historic landing thread (1st landing attempt & most recent missions)

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Reinhard

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Currently rumors point towards SN11 being unable to land safely on the pad due to engine failure, leading to activation of flight termination system.


So far, some kind of engine issue - wether internal or triggered by fuel supply issues - seems to be the main issue with the current state of the Starship test campaign. That's not limited to flights. It's a regular occurrence, that SpaceX swaps at least one engine between the first static fire and flight.

Reinhard
 
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Marc_G

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I recall a lot of time working with the FTS last week... Friday? ... Good thing they got that part right.

Still I'm heartened by the rapid cycling and rework and retest. In a govt program each "failure" would result in interminable delay. Spacex is learning from each EXPERIMENT and chugging along.
 

Reinhard

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I wonder if they wished they had waited for the fog to lift, so they could get better images of the flight?
Could be. On the other hand it was probably less damaging from a PR perspective that the explosion in the air was hidden from public view. I imagine an air burst might scare some people more than ground fireworks - even though this was safer than letting it impact.

Reinhard
 

Troy3003

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Currently rumors point towards SN11 being unable to land safely on the pad due to engine failure, leading to activation of flight termination system.


So far, some kind of engine issue - wether internal or triggered by fuel supply issues - seems to be the main issue with the current state of the Starship test campaign. That's not limited to flights. It's a regular occurrence, that SpaceX swaps at least one engine between the first static fire and flight.

Reinhard
I took some screen grabs from the video, it sure looks like it was a burn through or fuel line maybe.
Screenshot_20210330-194041_Chrome.jpg
Screenshot_20210330-194043_Chrome.jpg
Screenshot_20210330-194044_Chrome.jpg
 

OverTheTop

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I took some screen grabs from the video, it sure looks like it was a burn through or fuel line maybe.
I was wondering the same thing. It seemed too localised, not like some of the flash-fires that happen when a pocket of gas catches fire momentarily.
 

georgegassaway

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The engine section ended up here, right of "StarHopper" mostly out of the picture at far left).


 

Mushtang

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Sorry, I got really "ticked" when within a couple of minutes of the explosion, one of the "expert commentators" on NASAspacelfight talked about the "awesome" explosion.
Seriously? I'm willing to bet a lot of money that in no way was he suggesting that the explosion was what he was hoping for, or that he was glad it exploded instead of landing.
 

Winston

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Currently rumors point towards SN11 being unable to land safely on the pad due to engine failure, leading to activation of flight termination system.
Hopefully, the flight termination uplink is extremely well encrypted.

MONITOR SPACEX ROCKET TELEMETRY WITH SOFTWARE-DEFINED RADIO
11 Mar 2021


 

georgegassaway

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Scott Manley's take on the SN-11 explosion. Bottom line, he has some theories but nothing seems to quite fit or make enough sense. But he is pretty sure it was not an automated self-destruct, as some had claimed elsewhere.

 

Peartree

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Scott Manley's take on the SN-11 explosion. Bottom line, he has some theories but nothing seems to quite fit or make enough sense. But he is pretty sure it was not an automated self-destruct, as some had claimed elsewhere.

Odd, that's not what I understood him to say. From my viewing, Manley repeated that the SpaceX folks are quite insistent that it wasn't an automated self-destruct, but Manley himself didn't seem quite so convinced. He left open the possibility that the self-destruct might have, somehow, happened without telemetry that told SpaceX that it was happening and he did suggest that an automated self-destruct would fit well with what we know of the debris disbursement and the condition of fuel tanks, etc. Given the visible evidence, Manley seemed surprised that SpaceX was insisting that it *wasn't* a self-destruct.
 

georgegassaway

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Odd, that's not what I understood him to say. From my viewing, Manley repeated that the SpaceX folks are quite insistent that it wasn't an automated self-destruct, but Manley himself didn't seem quite so convinced. He left open the possibility that the self-destruct might have, somehow, happened without telemetry that told SpaceX that it was happening and he did suggest that an automated self-destruct would fit well with what we know of the debris disbursement and the condition of fuel tanks, etc. Given the visible evidence, Manley seemed surprised that SpaceX was insisting that it *wasn't* a self-destruct.
Well, I heard the part where he related that SpaceX said it was not a self destruct. I was playing the video as I was making dinner so apparently missed him concluding that it had to be a self destruct.

My reference to others saying it was self-destruct , were people on a couple of sites claiming that the automated self destruct activated because it was supposedly not on course to land in the landing zone. But then aerial photos were oddly showing the engine parts say just a bit west of the landing pad, and the nose say just a bit east of the landing pad.... implying it exploded OVER the landing pad (or close to it). Although actually since it moves horizontally a bit during the transition they need to aim it to fall a bit short of the landing pad for reignition, but surely they'd never make the criteria so finicky that it would self-destruct when it was a few hundred feet off).

Anyway, lacking info directly from SpaceX and seeing that SN-11 was not grossly out of the landing area, I was having great doubts about the claims of automated self destruct (at least for those claiming it triggered for being out of the landing area).

And now this update:
Here’s a short video, showing issues with SN-11’s #2 engine shortly after liftoff. That much was known, the video puts that into perspective.

The big piece of new info is that it includes a tweet by Elon Musk that when engine #2 was re-ignited for landing, it exploded (well, he wrote “hard start”. But then he also described the first attempt to land an F-9 onto an ASDS barge, screaming in at a 45 degree Kamikaze attack type angle, smashing it bits on impact, as a “hard landing” ).

So, unless Elon Musk was being misleading or obtuse*, engine 2 blew up, causing SN-11 to blow up .

* - Yes there is a possibility that engine #2 did not directly blow up SN-11. Perhaps that when it blew it could have caused enough damage to a critical system, or other out-of-normal range criteria, that the automated self-destruct was triggered after all. But if so, why wouldn't he simply say so? Well, he does have a history of just that kind of thing ["hard landing"], so I would consider that possibility open.


BTW - what the video refers to as anti-slosh baffles (seen in a view inside of a tank), they do also serve double duty as stiffener rings.

So, hopefully SN-15 flies before the month is over and it works. There's lots of changes to it, pretty much a new version compared to SN-8 thru SN-11.
 
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davel

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The big piece of new info is that it includes a tweet by Elon Musk that when engine #2 was re-ignited for landing, it exploded (well, he wrote “hard start”. ... ).
So, unless Elon Musk was being misleading or obtuse*, engine 2 blew up, causing SN-11 to blow up .
My understanding is that the term "Hard Start" as it is used in regards to rocket engines, is an over-pressurization at start up. This may or may not be enough to cause the engine to "Blow up".
 

georgegassaway

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My understanding is that the term "Hard Start" as it is used in regards to rocket engines, is an over-pressurization at start up. This may or may not be enough to cause the engine to "Blow up".
Yes, exactly. But also a "hard L:anding" is one that damages but does not obliterate the vehicle. And as I refereed to in my post, Musk called the Kamikaze 45 degree high speed crash of an F9 booster into an ASDS barge... a "hard landing", and not a CRASH. (Until finally seeing video days later, I had imagined it almost made it an just landed a bit too fast. This began my not trusting Elon Musk’s statements very much after that. He had even claimed there was no video...that very crash video that was released days later. And he'd also said before release that it was too dark to see anything anyway....it was highly visible in the eventually released video. So, yeah.).

And also as I mentioned, he can be misleading and obtuse, without speaking as straightforward as one would expect. In any case, he refers to the engine "hard start" as the cause of the explosion, or RUD, or whatever he wants to call the “Sudden Non-Existence" of SN-11.
 
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BEC

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...meanwhile, another Starlink batch is due to fly at 12:34 EDT tomorrow. I'm sure the streams will be in the usual places.
 

Mushtang

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79th successful recovery. That's super impressive!!

SpaceX should invite this team over to Boca Chica.
 

georgegassaway

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Video of today’s F-9 launch of Starlink satellites. The launch view after staging sucked (No onboard camera at the time), but the landing onboard view makes up for it.

For the landing, I do not recall such a clear blue ocean view from onboard like that, usuallly there are clouds and/or very rough waves. For awhile I thought the camera feed had frozen, no apparent option of the blue and the gird fins were not moving at the time either. Finally it got low enough for wave ripples to be visible among the blue. And you could see the shadow of the F9 booster on the water as it neared the surface.

 

Charles_McG

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I just read a SpaceflightNow article on an anticipated flight rate increase from Vandenburg.

Have they moved one of the landing ships back to the west coast? It seems like at some pace, they'll need another drone ship.
 

Winston

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Scott Manley's take on the SN-11 explosion. Bottom line, he has some theories but nothing seems to quite fit or make enough sense. But he is pretty sure it was not an automated self-destruct, as some had claimed elsewhere.

During NRO launches, they didn't broadcast their usual on-board videos and I hope they weren't stupid enough to send THAT telemetry unencrypted, but if they have always HAD an encryption option in their downlink hardware and firmware, why would they not encrypt even for unclassified launches if the capability was already there? To not allow adversaries to obtain encrypted samples for analysis on a regular basis?

That's a stretch since that shouldn't matter with good encryption. And as discussed in the comments to this article, time lag shouldn't be a problem with special hardware to accelerate encryption/decryption.

Anyway, as I've said before, I hope their range safety destruct link was highly secure.

FUN WHILE IT LASTED, FALCON 9 TELEMETRY NOW ENCRYPTED
April 7, 2021


A few weeks back we brought word that Reddit users [derekcz] and [Xerbot] had managed to receive the 2232.5 MHz telemetry downlink from a Falcon 9 upper stage and pull out some interesting plain-text strings. With further software fiddling, the vehicle’s video streams were decoded, resulting in some absolutely breathtaking shots of the rocket and its payload from low Earth orbit.

Unfortunately, it looks like those heady days are now over, as [derekcz] reports the downlink from the latest Falcon 9 mission was nothing but intelligible noise. Since the hardware and software haven’t changed on his side, the only logical conclusion is that SpaceX wasn’t too happy about radio amateurs listening in on their rocket and decided to employ some form of encryption.

Since this data has apparently been broadcast out in the clear for nearly a decade before anyone on the ground noticed, it’s easy to see this as an overreaction. After all, what’s the harm in a few geeks with hacked together antennas getting a peek at a stack of Starlink satellites? [derekcz] even mused that allowing hobbyists to capture these space views might earn the company some positive buzz, something Elon Musk never seems to get enough of.

On the other hand, we know that SpaceX is actively pursuing more lucrative national security launch contracts for both the Falcon 9 and Falcon Heavy. For these sensitive government payloads, the normal on-screen telemetry data and space views are omitted from the company’s official live streams. It seems likely the Pentagon would be very interested in finding out how civilians were able to obtain this information, and a guarantee from SpaceX that the link would be encrypted for all future flights could have helped smooth things over.

At the end of the post [derekcz] echos a sentiment we’ve been hearing from other amateur radio operators recently, which is that pretty soon space may be off-limits for us civilians. As older weather satellites begin to fail and get replaced with newer and inevitably more complex models, the days of picking up satellite images with an RTL-SDR and a few lines of Python are likely numbered.


 

georgegassaway

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"Elon Musk confirms that SpaceX is done trying to catch its rocket components"




So, they will still retrieve the fairing halves, just not try to catch them to keep them dry anymore (They have hired/leased a new ship to do that, to get both farings per trip). SpaceX customers do not want to deal with the potential contamination issues of fairings that have landed in the ocean. But since SpaceX is flying more payloads now than any customers, they will keep on reusing the fairings that landed wet, which also avoided damage.

I still think this woulda worked better.....with a grappling hook..... :)

 
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rklapp

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"Elon Musk confirms that SpaceX is done trying to catch its rocket components"




So, they will still retrieve the fairing halves, just not try ot catch them to keep them dry anymore (They have hired/leased a new ship to do that, to get both faring per trip). SpaceX customers do not want to deal with the potential contamination issues of fairings that have landed in the ocean. But since SpaceX is flying more payloads now than any customers, they will keep on reusing the fairings that landed wet, which also avoided damage.

I still think this woulda worked better.....with a grappling hook..... :)

What's the big deal? You pull the fish and seaweed out of the fairing then let it dry. :)
 

Mushtang

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So next Thursday SpaceX is scheduled to launch Crew-2 to the space station, this time with 4 people on board just like the Crew-1 mission.

I was just reading up on the schedule and came across this article that says something pretty interesting. Apparently they have reason to believe they've had more liquid oxygen in their tanks than they realized on every Falcon 9 flight so far. It hasn't caused any problems but they want to nail it down before next week's crewed flight.

"Gerstenmaier said engineers discovered the liquid oxygen discrepancy after bad weather interrupted a test of a Falcon 9 booster in Texas.

“We changed some of the configuration, and that gave us some insight we don’t normally get, and we got to see that the amount of oxidizer that we had loaded into the tank was a little bit different than what we had analyzed it to be,” Gerstenmaier said. “For the first time, we saw a small difference in loaded oxidizer. Because of that difference, we want to investigate that some more and look at the consequences of what that could mean. This is a configuration we’ve flown in for all our flights, so it’s not something new to us.”

Gerstenmaier characterized the issue as small. He said the propellant level in the Falcon 9 liquid oxygen tank was about 3 to 4 inches different than SpaceX expected, but added that engineers were “still studying to see if it’s really real, and the actual magnitude.” the issue was only found on the Falcon 9 first stage, according to Gerstenmaier."
 
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