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

[Kabloona]

Probably he's seeing the uneven sooting in the semicircles made by the leg cutouts at the base of the stage and thinking it looks like buckling.

[chalz]

This is the only thing that might be called 'bending'.
I could not find any close ups of that end of the F9 FT, the v1.1 looks different.

[SVBarnard]

i have a question so please help. What is that S shaped thing on the big screen in the control room? Its at exactly 34:23 please take a look

I am looking at it and going what view is that, what is it?

[Lars-J]

This is the only thing that might be called 'bending'.
I could not find any close ups of that end of the F9 FT, the v1.1 looks different.

I see what you are pointing at, but I think it is just a trick of the light, plus some uneven soot deposits from the last burn. We should see much better pictures soon.

This area looks the same as the 1.1 model. But it is not the same side of the booster... The post-landing picture is taken from the booster side that faces the strong-back at launch (it has the whole exterior "pipe" running the length of the stage), so there are few pictures of it.

[drzerg]

same pipe "bend" here
http://www.launchphotography.com/SpX-6_landing.JPG
so its a part of the design.

[woods170]

The European launcher does have an edge in reliability that will take some time to beat, if SpaceX can beat it. 69 successes in a row is reassuring when you want to put an 8 or 9 billion dollar telescope in orbit.

Matthew

Ariane 5 had SEVERAL major failures in its first flights. Falcon 9 has had 1 out of 20. SpaceX will beat it in time.

Ariane 5 had two full failures (LOM) and two partial failures in it's first 14 missions. SpaceX did in fact do a lot better with Falcon 9 having only one full failure (LOM) and only one partial failure in 20 missions.
Despite Ariane 5 having a worse EARLY track-record, it has become one of the most reliable launch vehicles in existence today. There is not much that stands in the way of Falcon 9 becoming just as reliable, or even more reliable.

[Apollo-phill]

Unless someone can inform from SpaceX control room , it appears to be a an  "view" of the returned 1st stage on the touchdown pad.

A-P

[kevinof]

same pipe "bend" here
http://www.launchphotography.com/SpX-6_landing.JPG
so its a part of the design.

Agreed and I wouldn't call it a bend, more like tapering but looks like it's designed that way.

[Apollo-phill]

I'm intrigued by the colour (color) difference of the "returned" first stage verssu its launch condition (see images).

Is that lower part due to scorching through  re-entry heating ?

Very geometric if it is and doesn't seem to have touched the still "white" landing leg "covers"

At first - seeing the immediate nighttime landing images thought may have been lighting conditions but it is still there in the daylight recovery images being posted now.

Just intrigued.

A-P

[HVM]

...what is this soot...

Falcon runs on kerosene -Have you ever touch the inside of a exhaust pipe?

[Hankelow8]

...what is this soot...

Falcon runs on kerosene -Have you ever touch the inside of a exhaust pipe?

You also have to realise on descent the rocket is travelling through it's exhaust not away from it, no doubt thats
when the soot build up occurred.

[Decius_Caecilius_Metellus]

Just found this video with almost the full landing burn in it. There isn't much to be seen, but I thought I would post it anyway ^^

[Chris Bergin]

Thread trim as this is about this mission, not some old article that wasn't about this mission talking nonsense about SpaceX. Off topic, politics, weak comment = removed (along with the responses, obviously).

[andrewsdanj]

...what is this soot...

Falcon runs on kerosene -Have you ever touch the inside of a exhaust pipe?

You also have to realise on descent the rocket is travelling through it's exhaust not away from it, no doubt thats
when the soot build up occurred.

On the soot front - you can get some seriously whacky flow recirculation coking up your pristine white paintwork going uphill too:

[Ben the Space Brit]

Regarding the soot-free band on core, I haven't yet had any kind of response to my own suggestion as to a possible explanation. So, it's reposted below.

I wonder why the returned stage has a white band in the middle with less soot than above and below.

This is only a guess on my part but I wonder whether the answer lies in the flow dynamics of the exhaust and atmospheric gasses around the core during descent. I'm no expert on laminar flow dynamics, but isn't it possible that there was a 'cool void' of trapped low-energy gas around the middle of the vehicle during re-entry that stopped fusion and combustion products from depositing on that part of the hull? The gas flow curved back towards the hull towards the top of the vehicle and, of course, were nearly in contact close to the engines, meaning that burns appeared on those parts of the hull.

I have absolutely no idea if this is actually realistic; it's just something that occurred to me after remembering seeing videos of supersonic air flow tests around air-frames. There are voids where the flow doubles back on itself in those and even establishes isolated rotating cells disconnected from the rest of the airflow.

[gospacex]

Half of russian space forum members are still in denial

[rpapo]

Half of russian space forum members are still in denial

Why would they be?  The original proposal for the flight path the Falcon stage took was a Russian one.  We don't know if Musk, or his staff, ever saw that, though.

[andrewsdanj]

Regarding the soot-free band on core, I haven't yet had any kind of response to my own suggestion as to a possible explanation. So, it's reposted below.

I wonder why the returned stage has a white band in the middle with less soot than above and below.

This is only a guess on my part but I wonder whether the answer lies in the flow dynamics of the exhaust and atmospheric gasses around the core during descent. I'm no expert on laminar flow dynamics, but isn't it possible that there was a 'cool void' of trapped low-energy gas around the middle of the vehicle during re-entry that stopped fusion and combustion products from depositing on that part of the hull? The gas flow curved back towards the hull towards the top of the vehicle and, of course, were nearly in contact close to the engines, meaning that burns appeared on those parts of the hull.

I have absolutely no idea if this is actually realistic; it's just something that occurred to me after remembering seeing videos of supersonic air flow tests around air-frames. There are voids where the flow doubles back on itself in those and even establishes isolated rotating cells disconnected from the rest of the airflow.

I don't think you'd get anything like those clear delineations. I'm going for most of the soot being deposited whilst going uphill, with soot being deposited on top of the LOX tank skin ice. Said ice then melts et voila.

[Rocket Science]

Chris,
Would it be possible to verify the launch/landing wind speed limit of (less than 50) if SpaceX makes themselves available in the near future?

Thanks
Rob

[gospacex]

Half of russian space forum members are still in denial

Why would they be?

Delusions of grandeur, I suppose. The thought that "stupid Americans" progress further than Russia is too much to admit to themselves.