-
#120
by
input~2
on 23 Jul, 2018 19:47
-
From the Catalog:2018-059A 43562 TELSTAR 19V 317.93 minutes 27.02 degrees 17862 km 243 km
-
#121
by
IainMcClatchie
on 24 Jul, 2018 05:22
-
I noticed two odd things about the upper stage burn.
First at 17:46 in the video (
), you can see that a few seconds after the second stage has started up the flexible reflective fabric around the upper engine suddenly puffs up. Does anyone know why that would happen?
Then, after a few more seconds, something at the bottom of the fabric covered area on the MVac makes a jerky motion about once per second. I've circled the area where it happens in the attached picture. Does anyone know what that might be?
Thanks!
-
#122
by
tyrred
on 24 Jul, 2018 06:01
-
The mylar blanket around the MVAC base is a beast of it's own, it has exhibited similar behavior over many of the past launches. Go back and watch the last few launches for the beating heart of the Mvac. Exhaust ports/relief valves in action?
-
#123
by
Jarnis
on 24 Jul, 2018 06:35
-
You are looking at it in vacuum. Even a tiny bit of gas inside the blanket would "puff it up". Also once it is "puffed up", there is nothing to make it collapse again. Even if all that gas just escapes from under the blanket, it stays puffed up unless something pushes it from the outside.
-
#124
by
Steven Pietrobon
on 24 Jul, 2018 09:22
-
Could you compare with JCSAT-16? It's a close match telemetry-wise, but the final orbit from F9 was 184 km × 35,912 km × 20.85°.
Using my all singing, all dancing GTO program I get the following values. Difference is 592 m/s. For those who don't have my program, it is attached.
Enter initial perigee height (km): 243
Enter initial apogee height (km): 17863
Enter required inclination change (deg): 27
theta1 = 0.34 deg, dv1 = 479.9 m/s
theta2 = 26.66 deg, dv2 = 1793.4 m/s
dv = 2273.3 m/s
Enter initial perigee height (km): 184
Enter initial apogee height (km): 35912
Enter required inclination change (deg): 20.85
theta1 = 20.83 deg, dv1 = 1678.8 m/s
theta2 = 0.02 deg, dv2 = 2.5 m/s
dv = 1681.3 m/s
-
#125
by
envy887
on 24 Jul, 2018 14:10
-
You are looking at it in vacuum. Even a tiny bit of gas inside the blanket would "puff it up". Also once it is "puffed up", there is nothing to make it collapse again. Even if all that gas just escapes from under the blanket, it stays puffed up unless something pushes it from the outside.
Since the vehicle is accelerating, every part of it is under the force of its own weight. If it is disturbed by a puff of gas, it could "fall" back to it's original position.
-
#126
by
mn
on 24 Jul, 2018 14:11
-
You are looking at it in vacuum. Even a tiny bit of gas inside the blanket would "puff it up". Also once it is "puffed up", there is nothing to make it collapse again. Even if all that gas just escapes from under the blanket, it stays puffed up unless something pushes it from the outside.
Sounds good in theory but all the videos show it repeatedly puffing
-
#127
by
Elmar Moelzer
on 25 Jul, 2018 19:08
-
Seeing the stage returning on the droneship, it seems like it looks pretty clean considering that this was a pretty hot return. At least to me, it looks a lot cleaner than previous returned stages.
-
#128
by
IainMcClatchie
on 25 Jul, 2018 19:18
-
I'm trying to imagine what would cyclically puff on an upper stage engine. I thinking it wouldn't be anything to do with the main combustion path, but rather the guidance system.
A 1 Hz cycle seems slow, but maybe when the thrust vector control tweaks the firing direction of the MVac, it either leaks a little propellant into the mylar bag (inflating it), or it causes the exterior gas pressure around the top of the MVac to momentarily rise, which collapses the bag a little against an extremely tiny interior pressure.
The upper stage uses cold gas thrusters for roll control, right? Maybe those things firing impinge on the bag a little.
-
#129
by
MarekCyzio
on 26 Jul, 2018 13:03
-
Anybody noticed that one of the LOX tank panels is significantly darker?
-
#130
by
cppetrie
on 26 Jul, 2018 14:22
-
Will be interesting to see if they fold up legs or remove them as they did with the first Block 5.
-
#131
by
Alexphysics
on 26 Jul, 2018 14:36
-
It seems they have disconnected the hydraulics from what The Aerospace Geek said yesterday on twitter so it's quite possible they'll remove them instead of folding them up. We'll see what happens
-
#132
by
ugordan
on 26 Jul, 2018 14:54
-
Anybody noticed that one of the LOX tank panels is significantly darker?
Even on the 1st block 5, I could discern (I think in prelaunch photos) that the top section of the LOX tank had a slightly different look, the area where the grid fins lockdown points are. I wonder if they're experimenting with different hydrophobic coatings or something.
It would also be interesting to know whether the noticeably less soot being deposited is due to such a coating or the fact they replaced the TPS around the engine area.
-
#133
by
Alexphysics
on 26 Jul, 2018 15:59
-
-
#134
by
Johnnyhinbos
on 26 Jul, 2018 18:21
-
-
#135
by
envy887
on 26 Jul, 2018 18:57
-
-
#136
by
TOG
on 27 Jul, 2018 00:47
-
Were the fairings halves recovered?
If you mean were they caught by a ship with the net on it? No. If the fairings had the recovery hardware installed, they may get picked up from the ocean surface. But SpaceX doesn't currently have a fairing catching ship on the east coast. Their only one Mr. Steven, which operates out of Los Angeles and attempts catching fairing halves from launches out of VAFB. Next attempt will be on the upcoming Iridium 7 launch.
This is an actual headline on CNN:
SpaceX loses multi million dollar fairing
The headline doesn't mention that the launch and primary mission were successful, nor does it mention that SpaceX landed the first stage in the worst conditions ever. Nope, the headline is about how SpaceX FAILED to catch the fairing.
Wow, are we disappointed in SpaceX for failing to do something that has NEVER been done by anyone before.
-
#137
by
TripleSeven
on 27 Jul, 2018 00:58
-
Were the fairings halves recovered?
If you mean were they caught by a ship with the net on it? No. If the fairings had the recovery hardware installed, they may get picked up from the ocean surface. But SpaceX doesn't currently have a fairing catching ship on the east coast. Their only one Mr. Steven, which operates out of Los Angeles and attempts catching fairing halves from launches out of VAFB. Next attempt will be on the upcoming Iridium 7 launch.
This is an actual headline on CNN:
SpaceX loses multi million dollar fairing
The headline doesn't mention that the launch and primary mission were successful, nor does it mention that SpaceX landed the first stage in the worst conditions ever. Nope, the headline is about how SpaceX FAILED to catch the fairing.
Wow, are we disappointed in SpaceX for failing to do something that has NEVER been done by anyone before.
just saw the CNN story it was in my view not that negative I guess mileage might vary
-
#138
by
Chris Bergin
on 27 Jul, 2018 01:39
-
-
#139
by
envy887
on 27 Jul, 2018 03:06
-
Were the fairings halves recovered?
If you mean were they caught by a ship with the net on it? No. If the fairings had the recovery hardware installed, they may get picked up from the ocean surface. But SpaceX doesn't currently have a fairing catching ship on the east coast. Their only one Mr. Steven, which operates out of Los Angeles and attempts catching fairing halves from launches out of VAFB. Next attempt will be on the upcoming Iridium 7 launch.
This is an actual headline on CNN:
SpaceX loses multi million dollar fairing
The headline doesn't mention that the launch and primary mission were successful, nor does it mention that SpaceX landed the first stage in the worst conditions ever. Nope, the headline is about how SpaceX FAILED to catch the fairing.
Wow, are we disappointed in SpaceX for failing to do something that has NEVER been done by anyone before.
just saw the CNN story it was in my view not that negative I guess mileage might vary
Negative is one thing. Factually incorrect is much another.
