SpaceX Falcon 9 - Iridium NEXT Flight 1 DISCUSSION (Jan. 14 2017)

[JohnWT]

is there any way to view expired/revoked licenses? (I only found "past launch permits" which only lists individual launches that actually took place)

You can see earlier iterations of the site on the Wayback Machine: http://web.archive.org/web/20160825164932/http://www.faa.gov/data_research/commercial_space_data/licenses/

[DatUser14]

From the Anomaly update posted today: http://www.spacex.com/news/2016/09/01/anomaly-updates


"this entails changing the COPV configuration to allow warmer temperature helium to be loaded"

Does this mean their getting rid of subcooled lox?

[toruonu]

From the Anomaly update posted today: http://www.spacex.com/news/2016/09/01/anomaly-updates


"this entails changing the COPV configuration to allow warmer temperature helium to be loaded"

Does this mean their getting rid of subcooled lox?

More likely means that they will not load so cool Helium meaning that the loading takes longer as LOX has to cool it and therefore He loading takes longer to reach the same total amount.

My question is does anyone have any idea on the launch window on 8th?

[Beittil]

No, just warmer helium which is i believe even colder than sub-cooled LOX (which is what froze the lox, causing this problem apparently).

[Torbjorn Larsson, OM]

Good to read!

But it leads to questions of course. Mine are:

If I understand correctly, it is the combination of low temperature and pressure during loading that pools the LOX, and if they revert to the old warmer helium loading the combination will prevent pooling? Seems it isn't a phase diagram problem as such, maybe it is a (somewhat peculiar) viscosity behavior.

Also, it seems they can proceed with an essentially sub-chilled LOX, just at a larger loading loss and a perhaps slightly higher temperature?

[DOCinCT]

Article - yeah, I had already written it, was just waiting for the SpaceX release

https://www.nasaspaceflight.com/2017/01/spacex-return-rtf-falcon-9-iridium-spacecraft/

Cool Nathan L2 render to lead it. 

Wondering about one paragraph:
As part of the corrective process, SpaceX has opted to avoid its press towards super chilled LOX for the interim until they are confident they can redesign the COPVs to cope with the colder chill process."
Does this impact the density of the LOX which is part of the ability to RTLS (or JRTI)?

[Star One]

It seems like it was their rush to change things up in a rapid way that directly contributed to this failure.

[Johnnyhinbos]

I wonder if this loading protocol change will apply to both stages - I'd assume both. I can't recall - did SpaceX pull the COPV manufacturing in-house, or are they still using the fabricator which experienced a COPV rupture in the past? Buckles in the AL liner sounds odd - AL extrusion for pressure cylinders is a pretty mature technology.

[IanThePineapple]

I think COPVs are made in-house, I believe I read that somewhere (I may be wrong though).

[mn]

Article - yeah, I had already written it, was just waiting for the SpaceX release

https://www.nasaspaceflight.com/2017/01/spacex-return-rtf-falcon-9-iridium-spacecraft/

Cool Nathan L2 render to lead it. 

Wondering about one paragraph:
As part of the corrective process, SpaceX has opted to avoid its press towards super chilled LOX for the interim until they are confident they can redesign the COPVs to cope with the colder chill process."
Does this impact the density of the LOX which is part of the ability to RTLS (or JRTI)?

I'm reading the relevant paragraph from the spacex report and I don't think this is what it means, SpaceX said "this entails changing the COPV configuration to allow warmer temperature helium to be loaded". They will use warmer helium to avoid freezing the LOX.

[yg1968]

Yes but there is also this part:  "as well as returning helium loading operations to a prior flight proven configuration based on operations used in over 700 successful COPV loads."

What does this mean?

[Jarnis]

Yes but there is also this part:  "as well as returning helium loading operations to a prior flight proven configuration based on operations used in over 700 successful COPV loads."

What does this mean?

Educated guess: Do not try to load so cold helium so fast and instead use warmer helium & slower load that gets cooled by the LOX?

[mn]

Yes but there is also this part:  "as well as returning helium loading operations to a prior flight proven configuration based on operations used in over 700 successful COPV loads."

What does this mean?

Educated guess: Do not try to load so cold helium so fast and instead use warmer helium & slower load that gets cooled by the LOX?

AND the fact that they are lumping subcooled lox with non subcooled lox in one 700 number, seems to me they are fudging things a bit.

[old_sellsword]

Yes but there is also this part:  "as well as returning helium loading operations to a prior flight proven configuration based on operations used in over 700 successful COPV loads."

What does this mean?

They were apparently testing a new, faster loading procedure.

It is also understood that SpaceX was testing modifications to the countdown sequence on the Static Fire Test for the previous Falcon 9 mission with JCSat-16 to introduce window management capabilities for the FT version of Falcon 9 that initially had to launch very shortly after propellant loading finished in order to avoid the chilled propellants warming up inside the tanks.

[Jim]

They were apparently testing a new, faster loading procedure.

It is also understood that SpaceX was testing modifications to the countdown sequence on the Static Fire Test for the previous Falcon 9 mission with JCSat-16 to introduce window management capabilities for the FT version of Falcon 9 that initially had to launch very shortly after propellant loading finished in order to avoid the chilled propellants warming up inside the tanks.

https://forum.nasaspaceflight.com/index.php?topic=41566.0

[yg1968]

OK. So SpaceX is saying that warmer helium will be loaded (not that super chilled LOX won't be used). Is that the consensus?

[Lar]

Bit of a blurry line  between 1) failure analysis and 2) what corrective action is being taken and 3) how it impacts this specific launch.  Let's be mindful of that.

[old_sellsword]

OK. So SpaceX is saying that warmer helium will be loaded (not that super chilled LOX won't be used). Is that the consensus?

Right. But I'm not sure why Chris wrote in his article that they won't be using subchilled LOX.

As part of the corrective process, SpaceX has opted to avoid its press towards super chilled LOX for the interim until they are confident they can redesign the COPVs to cope with the colder chill process.

Maybe he can stop by and explain that?

[yg1968]

Jim seems to have answered my question in the other thread:

It goes on to state the following:

"“In the short term, this entails changing the COPV configuration to allow warmer temperature helium to be loaded, as well as returning helium loading operations to a prior flight proven configuration based on operations used in over 700 successful COPV loads."

I read that to mean they are not just avoiding super chilled LOX, but return to the previous POR, which was LOX at boiling temperature.  It has a flight history of success, and at this point, I think that probably weighed heavily on SpaceX's decision making.   Their business priorities are to work through their manifest, stay on track with commercial crew, and get FH to first flight.   This action eases the path for all those.

No, they are not changing how they load LOX but how they load the helium.   They are just going to load it slower.

[Chris Bergin]

We'll know better after the Static Fire and the launch attempt per how they will load this F9. One thing we have heard is they have an extra COPV installed now. I did - but it could have been a mistranslation - hear they will only go back to super chilled LOX when they've redesigned the COPVs. But I bet - based on this thread's evaluation of the comments - it's about the HELIUM not the LOX.

Edited that line to avoid confusion.