SpaceX Falcon 9 FT - ORBCOMM-2 - Dec. 21, 2015 (Return To Flight) DISCUSSION

[Hog]

1) Can we guess which are the outer engines that fired for the boost back burns? my guess is the 1o clock and 7o clock ones.

In the enhanced image below, the insides of those engines definitely appear to be lighter in colour.

maybe someone can chime in on this.

Don't recall the Shuttle being this dirty.  Better get that Raptor engine up and running ASAP

Noticed for some time the Merlin "combustion" is dirty.  Sure the returned F9 has some ablative burnoff on it, but also elements from the dirty combustion. 

Wonder if this is will reflect in reuse.

That shuttle thing you refer to never really had to fly into its own exhaust.  The only time it fired while traveling backward was to de-orbit, which was in a  full vacuum atmosphere. 

There was one instance where retrograde thrusting was called for while on the SSMEs after the Powered Pitcharound(PPA).  Thank goodness it never had to be used. Though it was almost performed as STS-1, instead of the orbital flight ended up being performed.

[Ben the Space Brit]

It's amazing how quickly the target changes. First it's get the 2nd stage and payload to orbit successfully, then it's do this and get back to the ASDS (ideally without inconvenient RUD issues) then after flamboyantly achieving RTLS and landing  undamaged, we're quibbling over whether it's still got the showroom shine after all of that!

In fairness, we're all very interested to see just how 'reuse-ready' the vehicle is (as that is the final objective of the test program, after all). So, a lot of this is trying to anticipate possible problems based on what we can see in the few photographs released to date.

[Rocket Science]

What I find interesting is how the supersonic retrograde flow acts as an aerodynamic nose cone altering the shock wave and possible interactions along the length of the Falcon and any erosion seen...

http://www.nasa.gov/centers/marshall/about/star/star111116_prt.htm

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070013714.pdf

[Johnnyhinbos]

Does anyone have any info regarding the satellite launcher mechanism that deployed the OC-2 craft? I can't recall the third party that built it, and am curious as to the deployment tech

[somepitch]

Does anyone have any info regarding the satellite launcher mechanism that deployed the OC-2 craft? I can't recall the third party that built it, and am curious as to the deployment tech

I believe it is these guys: http://www.moog.com/products/spacecraft-payload-interfaces/

The ESPA Ring section references the OG2 mission.

Edit: Confirmed as 3 x ESPA Grande here: http://www.sncspace.com/ProductLines/OG2

[Rocket Science]

As was mentioned SNC and Moog...

[Comga]

I'm looking at the building... 
That is the first pic I have seen released of the inside on that building... 

It is big indeed. Here is an image from the SLC-40 HIF.

That's a great picture. I hadn't seen it before. One interesting thing is that you can see the engine number printed for each engine position.

It's the photo that was on the cover of Aviation Week back when the legs were the big news of the day.

[LouScheffer]

It's amazing how quickly the target changes. First it's get the 2nd stage and payload to orbit successfully, then it's do this and get back to the ASDS (ideally without inconvenient RUD issues) then after flamboyantly achieving RTLS and landing  undamaged, we're quibbling over whether it's still got the showroom shine after all of that!

It's not clear this is all quibbles.  For example, the cover over the bottom of the rocket separates the engine machinery from the nozzles.  Part of its function is to protect the rest of the engine from the radiant heat of the exhaust.  (And there are missions, such as Contour, that failed due to insufficient consideration of this.)  You could easily imagine a soot-black shield absorbing an order of magnitude more energy than the bright white one from the factory.  (Of course maybe it's not so white after the qualification and static fire burns - I have not seen any pictures of this.)  The point is that soot could be a performance issue as well as a cosmetic one.

[woods170]

It's amazing how quickly the target changes. First it's get the 2nd stage and payload to orbit successfully, then it's do this and get back to the ASDS (ideally without inconvenient RUD issues) then after flamboyantly achieving RTLS and landing  undamaged, we're quibbling over whether it's still got the showroom shine after all of that!

It's not clear this is all quibbles.  For example, the cover over the bottom of the rocket separates the engine machinery from the nozzles.  Part of its function is to protect the rest of the engine from the radiant heat of the exhaust.  (And there are missions, such as Contour, that failed due to insufficient consideration of this.)  You could easily imagine a soot-black shield absorbing an order of magnitude more energy than the bright white one from the factory.  (Of course maybe it's not so white after the qualification and static fire burns - I have not seen any pictures of this.)  The point is that soot could be a performance issue as well as a cosmetic one.

Emphasis mine:

Not quite white after the test firing at McGregor:
https://www.flickr.com/photos/spacexphotos/16856371855/sizes/o/

[ugordan]

You could easily imagine a soot-black shield absorbing an order of magnitude more energy than the bright white one from the factory.  (Of course maybe it's not so white after the qualification and static fire burns - I have not seen any pictures of this.) 

The lowest portion of the octaweb is black, starting with one of the AsiaSat launches. Of course, that doesn't necessarily mean it has the same thermal emissivity as the same finish with a coating of soot.

[Lars-J]

A close-up of the engines, post-landing...

https://twitter.com/SpaceX/status/684094378021801984

[corrodedNut]

That is a dirty bird...

[Semmel]

Looks like the cover around the top engine nozzle burned away.

Also interesting to see that the white stuff in the two engines is on the dark surface. Looks almost like dried up paint that dripped out the nozzles. I am pretty sure its not dried up paint though, doesnt belong there at all. But its definitely not a cleaned nozzle as was hypothesised before.

[Silmfeanor]

The white stuff almost looks sprayed on; note that it is also on some cloth covers. Might it be gypsum/concrete, sprayed into the nozzles during the final meters?

Or, although i have to concede I am totally clueless about this - some exotic fire suppresion agent? The force and reach seem to imply something applied with considerable power, however.

[Lars-J]

Looks like the cover around the top engine nozzle burned away.

Where do you see this? It looks zinged a bit, but then again flexible cloth (?) is right next to a turbo-pump exhaust. But it is still there.

[Semmel]

Looks like the cover around the top engine nozzle burned away.

Where do you see this? It looks zinged a bit, but then again flexible cloth (?) is right next to a turbo-pump exhaust. But it is still there.

I added some annotation to the image.

[Lars-J]

From the update thread:

This is a great pic! I am fascinated by the stuff revealed with the raceway cover removed. It's possible it's just the exposure of the photo, but it seems pretty sooty under that cover, which is surprising.

It's just the exposure, it looks clean to me. Here is a brightened version, note how much cleaner the area by the "raceway" is, what was under the external covers:

EDIT: Another thing we can see is that the exterior of the upper LOX tank is very clean. Its only the paint on the composite(?) interstage where some of the paint appears to have de-bonded and where we see most of the "damage" from the journey.

[Lars-J]

Looks like the cover around the top engine nozzle burned away.

Where do you see this? It looks zinged a bit, but then again flexible cloth (?) is right next to a turbo-pump exhaust. But it is still there.

I added some annotation to the image.

Yes, it looks slightly burned, but not "burned away". As in completely gone, which is how I interpreted your comment. I'm betting that the covers of all 8 exterior engines look the same on the inside.

[Llian Rhydderch]

Looks like the cover around the top engine nozzle burned away.

Where do you see this? It looks zinged a bit, but then again flexible cloth (?) is right next to a turbo-pump exhaust. But it is still there.

I added some annotation to the image.

Thanks for the notes on the image.

Question: can we tell that that cover is necessarily burned off?  Might it have been damaged somehow (supersonic turbulence, etc.) and blown off, before further blackening by soot?  Or something else entirely?

[Lars-J]

Thanks for the notes on the image.

Question: can we tell that that cover is necessarily burned off?  Might it have been damaged somehow (supersonic turbulence, etc.) and blown off, before further blackening by soot?  Or something else entirely?

It is not burned off, it is still there.