SpaceX F9 : CRS SpX-17 : May 4, 2019 - DISCUSSION

[edkyle99]

I think that‘s the long awaited scrub due to recovery related systems.
No more expending boosters if the droneship isn‘t ready.

On a NASA ISS mission no less

What's the world coming to?

I'm trying to remember if STS was ever scrubbed due to weather preventing SRB recovery.  I'm almost certain there were scrubs caused by Orbiter abort landing site weather issues.

 - Ed Kyle

[Bananas_on_Mars]

Remember, there were two, not just one, issues that scrubbed the launch on 3 May:
1. Drone Ship power issue and
2. Helium leak on ground side of the Stage 2 Quick Disconnect.

I think they found the leak after finishing the helium load? Might be a minor leak that would not necessarily result in a scrub and only shows in the data on a closed line, but definitely something to check out if they have to scrub anyhow. And it’s the reason why they’re lowering the rocket, which might  come with further requirements than detanking for a 24h scrub.

[Joffan]

Remember, there were two, not just one, issues that scrubbed the launch on 3 May:
1. Drone Ship power issue and
2. Helium leak on ground side of the Stage 2 Quick Disconnect.

I think they found the leak after finishing the helium load? Might be a minor leak that would not necessarily result in a scrub and only shows in the data on a closed line, but definitely something to check out if they have to scrub anyhow. And it’s the reason why they’re lowering the rocket, which might  come with further requirements than detanking for a 24h scrub.

They might also need to check/refresh the late-load items, which would also need Falcon horizontal (at SLC-40, anyway).

[gongora]

They might also need to check/refresh the late-load items, which would also need Falcon horizontal (at SLC-40, anyway).

They said at the press conference yesterday they wouldn't need to go horizontal or replace anything onboard for a one day scrub.

[Lar]

They might also need to check/refresh the late-load items, which would also need Falcon horizontal (at SLC-40, anyway).

They said at the press conference yesterday they wouldn't need to go horizontal or replace anything onboard for a one day scrub.

I presume that was if it was a weather scrub. If it was a technical issue, they might want to do that...

[gongora]

They might also need to check/refresh the late-load items, which would also need Falcon horizontal (at SLC-40, anyway).

They said at the press conference yesterday they wouldn't need to go horizontal or replace anything onboard for a one day scrub.

I presume that was if it was a weather scrub. If it was a technical issue, they might want to do that...

Yes, no reason to go horizontal for weather scrub.  They would go horizontal to fix their hardware.

[Sam Ho]

It's been hinted at above, but I think the "near to shore" position of the ASDS had a role here: even if they'd be okay with the risk of hitting the drone ship and crashing into the sea at the normal recovery location, there could be complicating factors doing so close to land. Much greater risk of debris washing up on beaches, for one. Also bureaucratic issues such as being bound by the preexisting hazard notices, etc.

I think that‘s the long awaited scrub due to recovery related systems.
No more expending boosters if the droneship isn‘t ready.

On a NASA ISS mission no less

What's the world coming to?

I'm trying to remember if STS was ever scrubbed due to weather preventing SRB recovery.  I'm almost certain there were scrubs caused by Orbiter abort landing site weather issues.

Given that SpX-16 did just that in December, I would imagine they know how to handle a near-shore water landing.  Also, the Hispasat 30W-6 launch last March landed a booster in the ocean where an ASDS would have been if the weather had been better.

Space Shuttle TAL site weather was a launch commit criterion, since it could affect LOC.  I believe the first scrub for TAL weather was STS-61C in January 1986.  STS-74 and 113 also scrubbed for TAL weather.

https://historycollection.jsc.nasa.gov/JSCHistoryPortal/history/reference/TM-2011-216142.pdf

[CJ]

First off, I'd like to thank the posters in the Update thread for all the updates!

NASA TV is showing this, which I just learned from the update thread, and means I'll be able to see it.

Coming up on the point where they had the scrub last time - fingers crossed the helium behaves. 

[Bananas_on_Mars]

Remember, there were two, not just one, issues that scrubbed the launch on 3 May:
1. Drone Ship power issue and
2. Helium leak on ground side of the Stage 2 Quick Disconnect.

I think they found the leak after finishing the helium load? Might be a minor leak that would not necessarily result in a scrub and only shows in the data on a closed line, but definitely something to check out if they have to scrub anyhow. And it’s the reason why they’re lowering the rocket, which might  come with further requirements than detanking for a 24h scrub.

Just mentioned on the webcast, the helium leak didn‘t threaten launch yesterday...

[obi-wan]

I’m hoping the velocity reading on screen is wrong - it’s showing 7535 m/sec, but circular orbital velocity at 214 km altitude is 7776 m/sec. (Also, doesn’t the velocity curve usually go all the way to the red line?) Did anyone hear a “nominal orbit” call?

[Steven Pietrobon]

Congratulations to SpaceX and NASA for the successful launch!

I’m hoping the velocity reading on screen is wrong - it’s showing 7535 m/sec, but circular orbital velocity at 214 km altitude is 7776 m/sec. (Also, doesn’t the velocity curve usually go all the way to the red line?) Did anyone hear a “nominal orbit” call?

The velocity is relative to Earth (which is why it starts at zero at liftoff). You need to add the Earth's rotation, plus compensate for the increase in speed as altitude increases.

[flyright]

I’m hoping the velocity reading on screen is wrong - it’s showing 7535 m/sec, but circular orbital velocity at 214 km altitude is 7776 m/sec. (Also, doesn’t the velocity curve usually go all the way to the red line?) Did anyone hear a “nominal orbit” call?

SpaceX commentator at T+09:16 confirmed a good orbit

[kdhilliard]

I’m hoping the velocity reading on screen is wrong - it’s showing 7535 m/sec, but circular orbital velocity at 214 km altitude is 7776 m/sec. (Also, doesn’t the velocity curve usually go all the way to the red line?) Did anyone hear a “nominal orbit” call?

SpaceX commentator at T+09:16 confirmed a good orbit

"Nominal orbital insertion" callout on the Countdown Net was 10 seconds after "And, M-Vac cutoff".
(I do wish they included a Countdown/MET clock on that view.)
https://youtube.com/watch?v=HhGfRSwXCUE&t=1727 takes you to the SECO call.

[Steven Pietrobon]

I've written a little program to calculate the inertial speed. This shows the estimated inertial speed is 7835.5 m/s and apogee is 397.9 km, pretty much spot on for the ISS altitude. This also calculates the required delta-V to reach ISS as 60.7 m/s. You can download the program from the link below.

http://www.sworld.com.au/steven/space/speed.zip

SpaceX speed calculator by Steven S. Pietrobon. 4 May 2019.
Enter negative perigee height to exit program.
Enter negative final orbit for geosynchronous orbit.

Enter initial perigee height (km): 207
Enter SpaceX speed (km/h): 27134
Enter initial orbit inclination (deg): 51.6

Estimated inertial speed = 7835.5 m/s
Estimated apogee height = 397.9 km

Enter required inclination change (deg): 0
Enter final orbit height (km): 408

Burn at   207.0 km: theta1 =  0.00 deg, dv1 =    2.9 m/s
Burn at   408.0 km: theta2 =  0.00 deg, dv2 =   57.8 m/s
dv =   60.7 m/s

[edkyle99]

50th v1.2 launch (already!).  A 51st Falcon 9 v1.2 was, of course, lost in the 2016 AMOS 6 WDR explosion.

Does anyone know if the NASA stream of the CRS-17 launch was saved anywhere?  The attached video was extracted from the NASA feed, which provided nice clean views without numbers all over the screen and unencumbered audio.

First Stage Landing Stats
as of 05/04/2019
---------------------------------------
Successes/Attempts      38/46*
F9 Successes/Attempts   34/40
FH Successes/Attempts    4/6*
OCISLY                  17/23*
JRTI                     7/8
CC LZ-1                 11/12
CC LZ-2                  2/2
VA LZ-4                  1/1
---------------------------------------
* FH-2 Core B1055.1 landed successfully on OSCILY, but subsequently 
  toppled and was lost.  Is not counted as a success in these numbers.

 - Ed Kyle

[FutureSpaceTourist]

I’ve often wondered how launch photographers frame their streak shots so well.

This from today’s CRS-17 launch blew my mind:

https://twitter.com/johnkrausphotos/status/1124609486122115073

I’m amazed that this stuff is even remotely predictable. 🚀 ❓❓❓

Here’s @flightclubio’s pre-launch prediction overlaid onto my long exposure image of the CRS-17 launch/landing. It was accurate enough that the real burns mostly obscure the prediction lines. Wow.

[Just Jake]

Wow, best landing views so far!

https://twitter.com/NASASpaceflight/status/1124568940917788673

Any idea where the infrared video just of the landing burn was taken from? LC #40? LZ #1? Go Quest?

[crandles57]

Just mentioned on the webcast, the helium leak didn‘t threaten launch yesterday...

Hmm.

The helium leak Todd referenced occurred with ground-based equipment. According to SpaceX, the company was monitoring the leak in the supply to helium on-board the rocket, but probably could have worked through the issue. Engineers wouldn't have known for sure until the last minutes of the countdown, however.

https://arstechnica.com/science/2019/05/after-scrub-spacex-targets-early-saturday-for-nasa-cargo-launch/

"probably could" doesn't seem to agree with "didn‘t threaten"

now found Hans quote

Hans: Helium leak on ground side last night.  Didn't get to the point last night to determine if that would have a been a scrub situation (not enough Helium onboard).  Helium leak was not a reason for the scrub but was fixed after the scrub.

so it looks like the webcast 'didn't threaten' was a little umm. "aspirational".

[litton4]

It's been hinted at above, but I think the "near to shore" position of the ASDS had a role here: even if they'd be okay with the risk of hitting the drone ship and crashing into the sea at the normal recovery location, there could be complicating factors doing so close to land. Much greater risk of debris washing up on beaches, for one. Also bureaucratic issues such as being bound by the preexisting hazard notices, etc.

I think that‘s the long awaited scrub due to recovery related systems.
No more expending boosters if the droneship isn‘t ready.

On a NASA ISS mission no less

What's the world coming to?

I'm trying to remember if STS was ever scrubbed due to weather preventing SRB recovery.  I'm almost certain there were scrubs caused by Orbiter abort landing site weather issues.

Given that SpX-16 did just that in December, I would imagine they know how to handle a near-shore water landing.  Also, the Hispasat 30W-6 launch last March landed a booster in the ocean where an ASDS would have been if the weather had been better.

Space Shuttle TAL site weather was a launch commit criterion, since it could affect LOC.  I believe the first scrub for TAL weather was STS-61C in January 1986.  STS-74 and 113 also scrubbed for TAL weather.

https://historycollection.jsc.nasa.gov/JSCHistoryPortal/history/reference/TM-2011-216142.pdf

Presumably if the weather conditions off the launch site were too rough, a Dragon-2 (and Starliner) crew launch would also be similarly delayed, since they would have the possibility of an abort into the sea...

[meekGee]

50th v1.2 launch (already!).  A 51st Falcon 9 v1.2 was, of course, lost in the 2016 AMOS 6 WDR explosion.

Does anyone know if the NASA stream of the CRS-17 launch was saved anywhere?  The attached video was extracted from the NASA feed, which provided nice clean views without numbers all over the screen and unencumbered audio.

First Stage Landing Stats
as of 05/04/2019
---------------------------------------
Successes/Attempts      38/46*
F9 Successes/Attempts   34/40
FH Successes/Attempts    4/6*
OCISLY                  17/23*
JRTI                     7/8
CC LZ-1                 11/12
CC LZ-2                  2/2
VA LZ-4                  1/1
---------------------------------------
* FH-2 Core B1055.1 landed successfully on OSCILY, but subsequently 
  toppled and was lost.  Is not counted as a success in these numbers.

 - Ed Kyle

Using as a reference, I draw a line after the experimental/development portion of the landing program.
The bulk of the landing failures occurred during that phase.

Once operational (about the start of 2017), there were 42 F9 filghts, and 2 FH flights, for a total of 48 cores.
Out of these 48 cores, there were 35 landing attempts. (13 non-attempts)

Out of these 35 landing attempts, there were 2 failures: the center core of FH1, and CRS16.
So the steady state landing reliability of the F9 system is currently 33/35 = 94%.

SpaceX lost and additional 1 core during non-flight operations.  (center core of FH2)

These numbers are significantly higher than what you present, since you're mixing the development phase failures with the operational phase.

It's a bit like saying that a certain disease kills 30% of the population, whereas in fact it used to kill 50%, then a cure was found, and now it kills 0.1%.  That little bit of extra knowledge completely changes the understanding of the situation.