Author Topic: First Falcon 9 Block 5 booster readying for static fire at McGregor (Read 24793 times)

envy887 · « **Reply #20 on:** 02/27/2018 05:57 pm »

Quote from: EngrDavid on 02/27/2018 01:57 pm

According to Wikipedia, the interstage is made from carbon fiber aluminum core composite. Has this changed and its now purely carbon fiber and that explains the black color? Or is the black color just because SpaceX decided not to paint it white.

Don't have to paint it, don't have to clean it. But I am curious what kind of TPS, if any, is on the interstage. That's going to get toasty on entry.

sunbingfa · « **Reply #21 on:** 02/27/2018 06:39 pm »

Forgive my naive question, but does Stage1 also contains COPV in its LOX tank?

cambrianera · « **Reply #22 on:** 02/27/2018 06:41 pm »

Quote from: matthewkantar on 02/27/2018 04:49 pm

The leg attachments look unchanged. Excited too see what the bottom of the rocket looks like up close. Looks like a metal band around the bottom? Inconel or titanium heat shield?

Matthew

Pattern of latches seems different.

Lars-J · « **Reply #23 on:** 02/27/2018 06:55 pm »

Quote from: Nomadd on 02/27/2018 03:34 pm

Quote from: JamesH65 on 02/27/2018 02:11 pm

Presumably nothing heat critical inside. Or perhaps carbon just looks cooler....

It doesn't just look cooler. Black would radiate heat better.

I think you are confused, black absorbs heat better. Not necessarily what you want. (which is why no fairings are painted black) But perhaps there are some other mitigating factors.

As for no paint, I certainly expect there to be some sort of coating over the carbon fiber to add some sort of protection.

RotoSequence · « **Reply #24 on:** 02/27/2018 07:05 pm »

Quote from: Lars-J on 02/27/2018 06:55 pm

I think you are confused, black absorbs heat better. Not necessarily what you want. (which is why no fairings are painted black) But perhaps there are some other mitigating factors.

Black is simultaneously the best absorber and radiator of heat.

docmordrid · « **Reply #25 on:** 02/27/2018 07:07 pm »

Quote from: sunbingfa on 02/27/2018 06:39 pm

Forgive my naive question, but does Stage1 also contains COPV in its LOX tank?

Yes.

meberbs · « **Reply #26 on:** 02/27/2018 07:08 pm »

Quote from: Lars-J on 02/27/2018 06:55 pm

Quote from: Nomadd on 02/27/2018 03:34 pm
Quote from: JamesH65 on 02/27/2018 02:11 pm

Presumably nothing heat critical inside. Or perhaps carbon just looks cooler....

It doesn't just look cooler. Black would radiate heat better.

I think you are confused, black absorbs heat better. Not necessarily what you want. (which is why no fairings are painted black) But perhaps there are some other mitigating factors.

How well something radiates heat is equal to how well it absorbs heat. If you are in a situation where your heat is not coming from radiation (e.g. contact from hot air) then black is the best color for cooling.

Most fairings don't worry about re-entry, and in the discussion of fairing re-use, I believe it has been stated their large ballistic coefficient means they should slow without much heating.

cambrianera · « **Reply #27 on:** 02/27/2018 07:14 pm »

Emission or absorption is related to wavelenght.
Color is related to visible spectrum wavelenght.
You can have a white that has low emission (and low absorption) in visible and high emission (and absorption) in infrared.

Lars-J · « **Reply #28 on:** 02/27/2018 07:23 pm »

Quote from: RotoSequence on 02/27/2018 07:05 pm

Quote from: Lars-J on 02/27/2018 06:55 pm
I think you are confused, black absorbs heat better. Not necessarily what you want. (which is why no fairings are painted black) But perhaps there are some other mitigating factors.

Black is simultaneously the best absorber and radiator of heat.

Yes but only after absorbing a lot of heat. It has a high thermal equilibrium if that makes sense.

But the point about certain materials ptentially more emissive/absorbing in different wavelengths is a good one.

cambrianera · « **Reply #29 on:** 02/27/2018 07:37 pm »

Quote from: Lars-J on 02/27/2018 07:23 pm

Quote from: RotoSequence on 02/27/2018 07:05 pm
Quote from: Lars-J on 02/27/2018 06:55 pm
I think you are confused, black absorbs heat better. Not necessarily what you want. (which is why no fairings are painted black) But perhaps there are some other mitigating factors.

Black is simultaneously the best absorber and radiator of heat.

Yes but only after absorbing a lot of heat. It has a high thermal equilibrium of that makes sense.

But the point about certain materials ptentially more emissive/absorbing in different wavelengths is a good one.

That's it.
You want good emission in long infrared for low temperature.
For high temperature TP (shuttle belly) you want high emission in visible (red/orange, but obviously black is easier).
And high absorption in visible is not a problem on this kind of TP.

abaddon · « **Reply #30 on:** 02/27/2018 07:55 pm »

Quote from: meberbs on 02/27/2018 07:08 pm

Most fairings don't worry about re-entry

While that is true, we're currently talking about the interstage, which re-enters at a high velocity along with the rest of the first stage.

[EDIT] I see you were replying to a comment about the fairing, so I think we're all in agreement here.

Elthiryel · « **Reply #31 on:** 02/27/2018 11:18 pm »

I've got some comments and questions regarding the article.

Quote

SpaceX developed the Full Thrust variant – sometimes incorrectly called “v1.2” – of the Falcon 9.

I don't think calling it v1.2 is actually incorrect. Some of the FT/v1.2 FAA launch licenses were certainly containing this name ("Falcon 9 Version 1.2", to be precise), I've attached the CRS-10 licence below.

Quote

Block 2 (B1021) was the first to be reused

I'm the one who tries to track which FT/v1.2 core was flying in which block version (I've even created an online spreadsheet to store this data

). For now, I presumed that the first Block 2 was 1021 (CRS-8), 1022 (JCSAT-14) or 1023 (THAICOM

, but most probably 1021 or 1022. So, for me, this is a very interesting piece of information, can you confirm it is legitimate? It would allow me to update my spreadsheet.

Tomness · « **Reply #32 on:** 02/28/2018 12:01 am »

I hope the full static fire, meets or exceeds all thrust requirements and Block V is locked down and start on Block V Heavy Center core.

RedSky · « **Reply #33 on:** 02/28/2018 12:17 am »

The SPACE X name seems much higher on the stage. Up in the frost LOX tank area... to keep the name protected from the sooty lower section?

joek · « **Reply #34 on:** 02/28/2018 12:20 am »

Quote from: RedSky on 02/28/2018 12:17 am

The SPACE X name seems much higher on the stage. Up in the frost LOX tank area... to keep the name protected from the sooty lower section?

And possibly with the additional stage thermal protection it will not be obscured by condensation/ice during launch. Will be interesting to see if there is a significant reduction.

Lars-J · « **Reply #35 on:** 02/28/2018 02:44 am »

Quote from: RedSky on 02/28/2018 12:17 am

The SPACE X name seems much higher on the stage. Up in the frost LOX tank area... to keep the name protected from the sooty lower section?

Nice catch, I was staring at it to see differences, but missed the most obvious.

They have also moved the logos that used to be on the interstage (F9, US flag) down to just below the interstage.

pargoo · « **Reply #36 on:** 02/28/2018 04:32 am »

I think you are confused, black absorbs heat better. Not necessarily what you want.

Don't forget the Russian use black fairings on Proton: Kristall, Zarya, etc.

Patchouli · « **Reply #37 on:** 02/28/2018 05:04 am »

Quote from: matthewkantar on 02/27/2018 05:39 pm

Quote from: neoforce on 02/27/2018 05:33 pm
I also missed the thermal protection change until this article. Is there any additional information about this? Is it a paint choice or some new material in the core? Does the interstate have this change? (Not sure if the interstate is considered part of the first stage or not)

The most surprising thing I noticed when I saw a used Falcon first stage in person was the use of cork as insulation. Amazing to me in 2017 the best product found for this application was tree bark. will be interesting to find out if the new protection includes cork.

Matthew

It's been used on a couple of other LVs such as the Delta II though I wonder if parts of it on the Block 5 booster have been replaced with insulation similar to AFRSI on the Shuttle?

Elmar Moelzer · « **Reply #38 on:** 02/28/2018 06:41 am »

I may have simply missed it on earlier first stage pictures (though looking through older pics, I cant seem to see them), or maybe it is not actually part of the stage but the crane, but there are some very visible "blocky things" on the top edge of the interstage. Are those part of the stage and if so, are they new additions?

Edit: Upon taking a closer look, I don't think they are actually part of the stage.

Ugger55 · « **Reply #39 on:** 02/28/2018 07:15 am »

On the question of the back interstage and is it a good/bad thing for heat, are we all getting a little too far led down the garden path of reasons, beyond just the "rule of cool" and ease of manufacture.

Rocket lab's entire rocket is black including it's fairing. It will launch from the cape and currently launches from somewhere hot enough to invalidate range conditions. If that were a reason to stay clear of black I'm sure they would have. Conversely, we would see more black rockets too if it helped?

Also, how valid are the considerations about reenty heating. The interstage will be in the lee side of the booster for comprehensive and atmospheric heating, but will be exposed to the turbulent air from the grid fin shock boundary. We all saw the results on the precious TPS the first hot re-entrys but I don't recall anything similar since re gridfins. Have they found a way to stop that impingement on the interstage or designed around that?