SpaceX Falcon 9 : Iridium NEXT Flight 2 (June 25, 2017) : Discussion

[VulpesJack]

So anyone want to venture a guess what this guy is doing up in a basket by S2 working in the fog?

https://forum.nasaspaceflight.com/index.php?topic=43149.msg1694447#msg1694447

(not a job for anyone with a fear of heights!)

Looks like he's working on the strongback in one of them, maybe they caught something on a camera and wanted to investigate in person (pure speculation)

[Scylla]

New curved profile ?

[cscott]

So anyone want to venture a guess what this guy is doing up in a basket by S2 working in the fog?

https://forum.nasaspaceflight.com/index.php?topic=43149.msg1694447#msg1694447

(not a job for anyone with a fear of heights!)

Does Vandenberg have the fast fallback TEL yet? Or it is still using it's old unmodified TEL?

[Norm38]

The fins really don't match, why not put on a white ablative coating to make them look nice and give an extra small bit of protection?

The goal is rapid turnaround with very little maintanence between flights. Having to replace or recoat parts is contrary to that. They're optimizing for cost.

[sevenperforce]

The fins really don't match, why not put on a white ablative coating to make them look nice and give an extra small bit of protection?

The goal is rapid turnaround with very little maintanence between flights. Having to replace or recoat parts is contrary to that. They're optimizing for cost.

Plus, why add a few extra kg for no meaningful advantage? Titanium can take the heat.

[Barrie]

The fins really don't match, why not put on a white ablative coating to make them look nice and give an extra small bit of protection?

The goal is rapid turnaround with very little maintanence between flights. Having to replace or recoat parts is contrary to that. They're optimizing for cost.

Plus, why add a few extra kg for no meaningful advantage? Titanium can take the heat.

Besides, the colour contrast looks pretty smart.  If only Falcon 9 could have a black and yellow colour scheme, like other power tools 

[FutureSpaceTourist]

Looks like all launch angles are covered:

Lots of fog today. Photo guys set up rigs at each yellow arrow. Crane in every shot. 😢

https://twitter.com/romn8tr/status/878839210274312192

[cambrianera]

Crop of above picture showing fin detail:

The fins really don't match, why not put on a white ablative coating to make them look nice and give an extra small bit of protection?

If you really want to protect a titanium part beforehand you would oxidize it, or even better make a titanium nitride layer. Titanium melts at 2 kK (1,700 degC) , titanium nitride at 3.2 kK. But if you do not do anything I expect it will react towards nitride over the somewhat less stable oxide at reentry, so it is all good relative extra protection.

If the end state is titanium nitride it will become dark gold tinted, but I would expect pretty much the same reflectance as in the photos. Most people experience titanium nitride as a nice color.

Titanium Aluminum Nitride (TiAlN or AlTiN)
A formed layer of aluminum oxide gives this tool better life in high heat applications. This coating is primarily selected for carbide tooling where little to no coolant is being used. AlTiN offers a higher surface hardness than that of TiAlN, along with different percentages of aluminum and titanium. It is another viable option in the world of HSM.
From http://www.moldmakingtechnology.com/articles/how-to-choose-the-right-tool-coating-for-your-machining-application
If you search images for TiAlN you can compare the color.

[Petr Čása]

Well well ... it looks like we are finally coming into the true space era - stil not titanium hull but ... we have to start somewhere
And I really can't wait to see postflight color of the grid fins. That will be true used rocket color - as we know from sci-fi until today

[edkyle99]

Second stage seems to be Block 3, if I squint enough to see through the fog.  I'll hold final opinion for hopefully clearer views.

 - Ed Kyle

[old_sellsword]

Second stage seems to be Block 3, if I squint enough to see through the fog.  I'll hold final opinion for hopefully clearer views.

 - Ed Kyle

Definitely Block 4. Attached image from here: https://flickr.com/photos/81789298@N05/sets/72157683148022571

[IanThePineapple]

Please explain to me, why does everyone think S2 is now Block 4? What evidence do they have?

I'm not trying to be rude there, unless there's some immediate evidence, people shouldn't jump to conclusions

[old_sellsword]

Please explain to me, why does everyone think S2 is now Block 4? What evidence do they have?

I'm not trying to be rude there, unless there's some immediate evidence, people shouldn't jump to conclusions

It's missing two of the four raceways that have been present on every Falcon 9 second stage since CASSIOPE, with the two notable exceptions of NROL-76 and Inmarsat-5 F4 (which both used the faster LOX loading procedure).

[sevenperforce]

Please explain to me, why does everyone think S2 is now Block 4? What evidence do they have?

I'm not trying to be rude there, unless there's some immediate evidence, people shouldn't jump to conclusions

It's missing two of the four raceways that have been present on every Falcon 9 second stage since CASSIOPE, with the two notable exceptions of NROL-76 and Inmarsat-5 F4 (which both used the faster LOX loading procedure).

Raceways?

What are those, exactly?

Sorry for my lack of knowledge.

[old_sellsword]

Raceways?

What are those, exactly?

Sorry for my lack of knowledge.

No worries. They're the things boxed in red, they (usually) just run cabling and plumbing outside the propellant tanks since it's harder to go through them.

EchoStar 23 on the left, Iridium-1 on the right, both Block 3 upper stages.

[Welsh Dragon]

Am I being blind or are we without a technical webcast again for this launch?

[dgates]

So.... we're roughly 4 hours from launch.  Weather forecast looks to be perfect.  What's going on right now?  I am guessing the launch team is gathering and going though a final pre-launch briefing process, pad crews are completing close-outs, etc.  Fuel and LOX plants are busy sub-cooling prop.  Range is manning up and conducting readiness reviews and checks. 

What else?

[edkyle99]

Stage 2 comparison between the two Iridium Next vehicles.  They are clocked slightly in these two views, but the umbilical tower is on the lift side in both photos.

 - Ed Kyle

[old_sellsword]

Stage 2 comparison between the two Iridium Next vehicles.

 - Ed Kyle

Those angles aren't quite the same. The raceway in your Iridium-1 picture is on the side of the second stage, the raceway in the Iridium-2 picture is on the front.

[sevenperforce]

And the difference between the raceways signifies what changes between Block 3 and Block 4?