SpaceX Falcon 9 : Merah Putih (Telkom 4) : August 7, 2018 - DISCUSSION

[groknull]

SpaceX image of F9-61 on the pad.

 - Ed Kyle

What are those markings on the middle of the core?!

Ha.  You beat me to it.  :-)  Just before I clicked to post the same question, I saw you had.
Looks like surface cleaning, probably to mount new sensors... or to re-rivet some internal structure?

I rather doubt SpaceX is riveting internal components on a flown core.

Rather, I suspect those marked up areas might be places where SpaceX did some down-to-the-metal surface cleaning to enable NDT (non-destructive testing) as part of their post-flight/pre-reflight evaluations of the new Block 5 cores.

Bingo.

That's exactly what you'd expect to see.  I bet we see the same markings in the same spot for this core until they establish data over multiple flights.

Those markings are within a rectangle which is slightly darker than the surrounding tank surface.  Somewhere upthread here, or in the Bangabandhu-1 discussion thread, there was, IIRC a discussion of that rectangle possibly being an experimental surface treatment area.  If that is the case, taking surface samples and doing wide area thickness measurements would make sense.

EDIT: Found it - Telstar 19 Discussion thread (same rectangle - different booster):
https://forum.nasaspaceflight.com/index.php?topic=43465.msg1841151#msg1841151
MarekCyzio asked, ugordan pondered possible reason.

[Halidon]

Have we seen the drone ship camera look up and then pan down before? Neat shot.

[GregA]

What were the sparks coming off the engine area after the re-entry burn (just before the camera stopped)?

[Llian Rhydderch]

Was the first time I ever noticed the droneship camera pan up first.

So I'm going with: new feature.

[RDMM2081]

What were the sparks coming off the engine area after the re-entry burn (just before the camera stopped)?

I a;so thought it was sparks at first, but thinking again I suspect condensed water from starting to hit the denser atmosphere?  Just a thought, interesting looking effect.

[Jarnis]

What were the sparks coming off the engine area after the re-entry burn (just before the camera stopped)?

Re-entry heating starting up. We've seen some sparkshows before during night launches when booster re-enters thicker atmosphere. Nothing new.

[ZachS09]

Really liking the music playlist during this coast phase.

Sounds like one of the songs got remixed with more instruments.

[lonestriker]

Landing looked to be dead center from the camera view and no extra fires post-landing, so they've pretty much figured out this whole "landing a booster" thing.

IIRC, we've seen sparks like that before on other S1 entries.  I think night launches in particular highlight that effect.

[Lar]

Have we seen the drone ship camera look up and then pan down before? Neat shot.

I too think not. It will be neat if they do this with a daylight landing.

[cscott]

Ablative thermal protection works by "burning off" the protective material, making the sparks you see. We've seen it on block 4; this is the first time on block 5, so it confirms that it's not all titanium heat shield newness, there's still some good old fashioned SPAM down there.

There were some interesting blue plasmas which lasted quite a while, that was interesting to see.  Blue is the color of ionized oxygen and violet is the color of ionized nitrogen; https://en.wikipedia.org/wiki/Ionized-air_glow has some nice pictures.  We don't see that in the daytime either.

No heat glow on the grid fins, just intermittent indirect illumination.

I wish they'd kept the camera on the descending first stage for longer.  I thought I saw a nice aurora on the limb of the Earth in one shot...

[edkyle99]

Maybe GEO-2,000 m/s or so.  Very approximate guesstimate.  Velocity increase was shown on the SpaceX screen going from 26,681 km/hr to 34,903 km/hr, or 2,284 m/sec.


 - Ed Kyle

[lonestriker]

Ablative thermal protection works by "burning off" the protective material, making the sparks you see. We've seen it on block 4; this is the first time on block 5, so it confirms that it's not all titanium heat shield newness, there's still some good old fashioned SPAM down there.

There were some interesting blue plasmas which lasted quite a while, that was interesting to see.  Blue is the color of ionized oxygen and violet is the color of ionized nitrogen; https://en.wikipedia.org/wiki/Ionized-air_glow has some nice pictures.  We don't see that in the daytime either.

No heat glow on the grid fins, just intermittent indirect illumination.

I wish they'd kept the camera on the descending first stage for longer.  I thought I saw a nice aurora on the limb of the Earth in one shot...

And a nice view of Florida city lights from space as well as some lightning.  I love night launches for the extra light show, but still prefer daytime launches for the better booster views.

[cscott]

Re-watching, it was definitely distant lightning, not an aurora.  Still very pretty!

I also noticed a strong purple halo during ascent and I'm wondering if that was ionized air glow as well.  Seemed to be strongest around max Q.

[TripleSeven]

Really liking the music playlist during this coast phase.

Sounds like one of the songs got remixed with more instruments.

https://soundcloud.com/testshotstarfish/sets/flight-proven-single

[Lupi]

Man, what a view. Nothing comes close to that.

https://imgur.com/a/lcSylfC these are the pics I was able to snap, but I wasn't taking it too seriously.
We saw entry burn at 401, about 30 degrees-ish above the horizon? Went behind the trees and the AFB gate, which we were close by to.

[Steven Pietrobon]

Two newly cataloged objects:

2018-064A   2018-08-07 06:57 UTC - 193/29503km/27.06°
2018-064B   2018-08-07 06:59 UTC - 181/29527km/27.04°

I get a delta-V of 1923.3 m/s to reach GEO.

Enter initial perigee height (km): 193
Enter initial apogee height (km): 29503
Enter required inclination change (deg): 27.06

theta1 =  0.08 deg, dv1 =  119.7 m/s
theta2 = 26.98 deg, dv2 = 1803.6 m/s
dv = 1923.3 m/s

[soltasto]

Two newly cataloged objects:

2018-064A   2018-08-07 06:57 UTC - 193/29503km/27.06°
2018-064B   2018-08-07 06:59 UTC - 181/29527km/27.04°

I get a delta-V of 1923.3 m/s to reach GEO.

Enter initial perigee height (km): 193
Enter initial apogee height (km): 29503
Enter required inclination change (deg): 27.06

theta1 =  0.08 deg, dv1 =  119.7 m/s
theta2 = 26.98 deg, dv2 = 1803.6 m/s
dv = 1923.3 m/s

I get almost identical numbers

[Jet Black]

SpaceX image of F9-61 on the pad.

 - Ed Kyle

What are those markings on the middle of the core?!

Ha.  You beat me to it.  :-)  Just before I clicked to post the same question, I saw you had.
Looks like surface cleaning, probably to mount new sensors... or to re-rivet some internal structure?

I rather doubt SpaceX is riveting internal components on a flown core.

Rather, I suspect those marked up areas might be places where SpaceX did some down-to-the-metal surface cleaning to enable NDT (non-destructive testing) as part of their post-flight/pre-reflight evaluations of the new Block 5 cores.

Bingo.

That's exactly what you'd expect to see.  I bet we see the same markings in the same spot for this core until they establish data over multiple flights.

I'm just the Messenger....Chris Bergin may have figured this out. Check his Twitter page......and look at this https://www.omniglot.com/conscripts/marain.htm

It's just such a Musk-ish thing to do .....and Elon is a big fan of Lain M Banks Culture Series

I'm not convinced by the Marain as it's based on a nine point grid. if you look though, the left has some additional vertical lines in the upper rows (2, then 1 then 3) and the right has two additional vertical lines at the bottom (2) with the rest being a reflection around the center line.

[ZachF]

The big question now, is when is this booster going to get flight number 3...

[Jakusb]

The big question now, is when is this booster going to get flight number 3...

I had this booster for Inflight Abort, but that got delayed a lot.
My money now is on 1048 being the first to make a third flight.