SpaceX And/Or Rocketry In General

Mike Hewson
Mike Hewson
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"many small charred

"many small charred hunks"

Darn. I was looking for a more cohesive strategy ..... DuckTape maybe ? What a quacking good idea ! It's known to work on Mars.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

archae86
archae86
Joined: 6 Dec 05
Posts: 3157
Credit: 7221344931
RAC: 975952

SpaceX has pushed out CRS-13

SpaceX has pushed out CRS-13 further until Friday (Florida time). "to conduct full inspections and cleanings due to detection of particles in 2nd stage fuel system." 

Furthermore, if they don't launch Friday, there is a gap in possibility until late December, driven by some ISS considerations.

Anonymous

archae86 wrote:"detection of

archae86 wrote:
"detection of particles in 2nd stage fuel system."

yikes!!!

Quote:
Furthermore, if they don't launch Friday, there is a gap in possibility until late December, driven by some ISS considerations.
Mike Hewson
Mike Hewson
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Joined: 1 Dec 05
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Credit: 316225317
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Ooooh. I wonder if this is

Ooooh. I wonder if this is code for ( another ) COPV related problem ?

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

archae86
archae86
Joined: 6 Dec 05
Posts: 3157
Credit: 7221344931
RAC: 975952

The CRS-13 flight was

The CRS-13 flight was pretty.  They had a good long-range camera on the stage separation moment.  I was struck by how very quickly the first stage not only turns around, but actually starts burning considerably before the turn is complete.  Maybe that is part of how they arrange not to damage the second stage, in addition to the efficiency gain from getting started before the stage is any farther downrange than required.

The final side view of the landing--at least the one used on the Technical webcast, was so flawless that it seemed more like a Sci-fi film than the real thing).

Anonymous

I just watched the replay on

I just watched the replay on youtube.  Its damn amazing.  During return-to-pad I believe you could see the outbound contrail.  Also that 1st stage is really moving until the last few feet.  I can only imagine the stress that first stage endures.  Well done SpaceX gals and guys.  Flawless!

Mike Hewson
Mike Hewson
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Posts: 6588
Credit: 316225317
RAC: 336789

According to one of the

According to one of the graphics they showed, I don't think there is any 1st stage loop-back going higher than the ongoing 2nd stage track. I think it is more of a loop-back going below ( at least initially after separation) even the prior rising track. It certainly returned pretty quickly IIRC c/w the usual high lob.

Flawless landing. The post conference mentioned that they felt no need to even repaint the barrel after it's prior launch ! :-)

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

archae86
archae86
Joined: 6 Dec 05
Posts: 3157
Credit: 7221344931
RAC: 975952

Nice landing indeed.  There

Nice landing indeed.  There was more than one camera going, and it appears that the NASA feed and the SpaceX feed made different camera selections most if not all the way down.  More than one person has posted a composite video to youtube using first one than the other.  If you have only seen one, you may enjoy seeing the other.

For example this one after eight seconds of promo starts with the NASA feed just as the re-entry burn lights up one engine, than goes on to three, and continues to touchdown, then switches to the version SpaceX broadcast.  This one only offers a maximum resolution of 720p60--you may be able to find higher.

The NASA feed, in particular, makes some of the variations in orientation of the stage to oncoming air more apparent than I realized.   They clearly are making some use of the (modest) lift available by holding the booster at an considerable angle of attack in the early hypersonic phase, but gradually reduce the angle of attack and get to near nothing late in the game.  

The SpaceX feed shows how the grid fin motions get larger and larger as aero forces available shrink with lower speed near the end.  I'm a bit surprised they don't just stow the things to a neutral position late in the game and rely purely on gimbal of the thrusting engine, but of course any utility they get out of the grid fins is a fuel savings.

Also the NASA footage shows the relight of the engines more clearly than I've noticed before, including the rather large "green flash" from the TEA-TEB ignition scheme, and makes crystal clear that this was a 1 engine goes to 3 re-entry burn with a single engine landing burn.

 

archae86
archae86
Joined: 6 Dec 05
Posts: 3157
Credit: 7221344931
RAC: 975952

The DigitalGlobe people

The DigitalGlobe people caught a satellite image of the landed booster getting hosed down.

Their twitter posted image shows a much newer and smaller landing pad not very far away at all from LZ-1 where this one landed.

It seems LZ-1 to the outer edge is about 650 feet diameter, with the dark part in the middle only a little over 200 feet diameter.  The much newer pad appears to be centered about 1000 feet away, with a paved diameter well under 400 feet.  

I realize they are motivated to land with as little remaining fuel and oxidizer as prudently feasible, but still I'm amazed at how close to other stuff they are landing this early in the game.

[I can't see what is wrong with my site reference syntax.  I wonder if Einstein is again not nice with these, or I am just a bit blind this evening.  Repair by a kindly moderator would be a blessing]

 

Mike Hewson
Mike Hewson
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Joined: 1 Dec 05
Posts: 6588
Credit: 316225317
RAC: 336789

In the post conference the

In the post conference the Dragon specialist lady seemed to imply that at least one thing the Heavy demo was waiting  upon was full preparation of LZ-2 : presumably this is that newer smaller pad you refer to. So I believe the Heavy 1st stage recoveries will be side boosters to LZ-1 and LZ-2 with centre booster to downrange drone ship.

You either use [url][/url] old style syntax OR the dialog invoked by hitting the chain-link icon/button on the function bar above your editing box.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

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