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SpaceX Vehicles and Missions => SpaceX Missions Section => Topic started by: sevenperforce on 05/06/2016 04:39 pm

Title: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/06/2016 04:39 pm
DISCUSSION THREAD for the Falcon 9 mission with Thaicom-8.

NET May 26.

UPDATE THREAD:
http://forum.nasaspaceflight.com/index.php?topic=40182.0 (http://forum.nasaspaceflight.com/index.php?topic=40182.0)

Resources:

SpaceX News Articles from 2006 (Including numerous exclusive Elon interviews):
http://forum.nasaspaceflight.com/index.php?topic=21862.0 (http://forum.nasaspaceflight.com/index.php?topic=21862.0)

SpaceX News Articles (Recent):
http://www.nasaspaceflight.com/tag/spacex/ (http://www.nasaspaceflight.com/tag/spacex/)

=--=

SpaceX GENERAL Forum Section:
http://forum.nasaspaceflight.com/index.php?board=45.0 (http://forum.nasaspaceflight.com/index.php?board=45.0) - please use this for general questions NOT specific to this mission.

SpaceX MISSIONS Forum Section:
http://forum.nasaspaceflight.com/index.php?board=55.0 (http://forum.nasaspaceflight.com/index.php?board=55.0) - this section is for everything specific to SpaceX missions.



=-=

Presumably this will have the same basic arrangement as the JCSAT landing: same MECO speed and altitude, but with a slightly large propellant reserve. Will be interesting to see whether they use the same three-engine suicide burn; would be beautiful to see that during the day.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: EngrDavid on 05/07/2016 04:06 am
Sorry, could not find the Thaicom discussion page so will post my observation here.
On the same spaceflight launch schedule page, it says the Thaicom flight was moved forward.  A first for SpaceX?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Flying Beaver on 05/07/2016 04:32 am
Sorry, could not find the Thaicom discussion page so will post my observation here.
On the same spaceflight launch schedule page, it says the Thaicom flight was moved forward.  A first for SpaceX?

The first Iridium launch out of Vandy somewhat recently was moved up from August to July. So no, not a first entirely, but possibly the first time a stage has been reassigned to another payload.

(FYI haven't check my facts, going off memory)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: NovaSilisko on 05/07/2016 07:32 am
A quiet milestone: assuming some schedule switcharoo doesn't take place, this launch should be host to the 191st through 200th Merlin 1D to fly (counting vacuum versions)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: deruch on 05/07/2016 05:57 pm
Sorry, could not find the Thaicom discussion page so will post my observation here.
On the same spaceflight launch schedule page, it says the Thaicom flight was moved forward.  A first for SpaceX?

The first Iridium launch out of Vandy somewhat recently was moved up from August to July. So no, not a first entirely, but possibly the first time a stage has been reassigned to another payload.

(FYI haven't check my facts, going off memory)

There was a core switch with one of the AsiaSat birds, either -6 or -8.  It was swapped with the core for CRS-4, if I recall correctly. 
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sunbingfa on 05/07/2016 08:17 pm
If RTLS result in 60% performance loss, then is it possible to try a RTLS on Thaicomm8 mission? It probably will be low margin but may be possible since Thaicomm8 is less than 3200kg according to Manufacturing information, while the max performance for F9 GTO mission is 8300kg.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: gongora on 05/07/2016 08:31 pm
Sorry, could not find the Thaicom discussion page so will post my observation here.
On the same spaceflight launch schedule page, it says the Thaicom flight was moved forward.  A first for SpaceX?

The first Iridium launch out of Vandy somewhat recently was moved up from August to July. So no, not a first entirely, but possibly the first time a stage has been reassigned to another payload.

(FYI haven't check my facts, going off memory)

There was a comment on Reddit that the stage wasn't reassigned, the stage for Thaicom got to McGregor after the one for Eutelsat/ABS, but the flight order got switched.  Don't know how accurate that is.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rockets4life97 on 05/07/2016 08:48 pm
If RTLS result in 60% performance loss, then is it possible to try a RTLS on Thaicomm8 mission? It probably will be low margin but may be possible since Thaicomm8 is less than 3200kg according to Manufacturing information, while the max performance for F9 GTO mission is 8300kg.

Thaicom 8 weighs less than JCSAT-14, so I think we can safely say that a successful landing on the drone ship is probable. :-)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: gongora on 05/07/2016 08:51 pm
If RTLS result in 60% performance loss, then is it possible to try a RTLS on Thaicomm8 mission? It probably will be low margin but may be possible since Thaicomm8 is less than 3200kg according to Manufacturing information, while the max performance for F9 GTO mission is 8300kg.

Thaicom 8 weighs less than JCSAT-14, so I think we can safely say that a successful landing on the drone ship is probable. :-)

I'll wait to see the weather forecast before I bet on that  :)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: tleski on 05/07/2016 10:05 pm
A stage was spotted leaving McGregor facility.
People are speculating it is the Thaicom-8 1st stage.
Posted by Keith Wallace in SpaceX Facebook group.

https://www.facebook.com/photo.php?fbid=1140023389349373&set=gm.10154211326321318&type=3
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: OxCartMark on 05/08/2016 01:12 am
Frustrating that at the supposed production rate the pipeline is not full and there's not already a good selection of F9s waiting at a warehouse near the cape.  We're chronologically far beyond where we should be tracking an individual custom built rocket for a specific flight.  Need to get production going, its not rocket science, its production. That's what we do over here in Detroit. Not sure whether I need to go out and fix the production problem for SpaceX or for Tesla Motors first.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: macpacheco on 05/08/2016 03:32 am
Frustrating that at the supposed production rate the pipeline is not full and there's not already a good selection of F9s waiting at a warehouse near the cape.  We're chronologically far beyond where we should be tracking an individual custom built rocket for a specific flight.  Need to get production going, its not rocket science, its production. That's what we do over here in Detroit. Not sure whether I need to go out and fix the production problem for SpaceX or for Tesla Motors first.
The only time SpaceX did 3 fast paced launches they had the opportunity to stockpile those stages ahead of time.

This is the first time SpaceX is keeping sub 4 week launch intervals without a previously full pipeline.

I bet this will continue until reuse becomes a thing and Hawthorne/McGregor only has to deal with 2nd stages and fairings plus perhaps one first stage for each 5+ launches. Until then production rates will continue to increase, but not enough to keep the whole pipeline full.

In summary, what for you is glass half full, for me is glass 75% full !

We'll get there Grasshopper !
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: wannamoonbase on 05/08/2016 06:54 am
Frustrating that at the supposed production rate the pipeline is not full and there's not already a good selection of F9s waiting at a warehouse near the cape.  We're chronologically far beyond where we should be tracking an individual custom built rocket for a specific flight.  Need to get production going, its not rocket science, its production. That's what we do over here in Detroit. Not sure whether I need to go out and fix the production problem for SpaceX or for Tesla Motors first.

How long have you been following Elon Musk led companies.  Stated production rates are aspirational, that's it.

With SpaceX they may not need more than 16 cores a year once re-use is figured out and accepted by customers.

Tesla production rate on th Cather hand 😏
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jim on 05/08/2016 12:59 pm
Frustrating that at the supposed production rate the pipeline is not full and there's not already a good selection of F9s waiting at a warehouse near the cape.  We're chronologically far beyond where we should be tracking an individual custom built rocket for a specific flight. 

Not true.  The design has not been static long enough.  There are still issues that have to be fixed that are fleet wide.  Also, what good is it to land stages and not use the inspection data for design updates?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mike_1179 on 05/08/2016 01:37 pm

Thaicom 8 weighs less than JCSAT-14, so I think we can safely say that a successful landing on the drone ship is probable. :-)

Not if they see something in the post landing inspections that makes them change other aspects of re-entry. If they see, for instance, that re-entry heating was too high to allow re-flight of the stage, perhaps a longer re-entry burn is required, so less prop for landing.

The goal is re-flight, not just recovery
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: edkyle99 on 05/08/2016 03:10 pm
Frustrating that at the supposed production rate the pipeline is not full and there's not already a good selection of F9s waiting at a warehouse near the cape.  We're chronologically far beyond where we should be tracking an individual custom built rocket for a specific flight.  Need to get production going, its not rocket science, its production. That's what we do over here in Detroit. Not sure whether I need to go out and fix the production problem for SpaceX or for Tesla Motors first.
This is merely "just-in-time" delivery.  ULA, Arianespace, Roskosmos, etc., all use the same methods.

 - Ed Kyle
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/08/2016 03:17 pm
If the thermal loading on these GTO missions is just too high to land without extensive damage, I wonder whether they would add GTO-specific TPS, or even sacrificial TPS.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: philw1776 on 05/08/2016 05:02 pm
If the thermal loading on these GTO missions is just too high to land without extensive damage, I wonder whether they would add GTO-specific TPS, or even sacrificial TPS.

Not easily done, but that's beside the point in that the loading is high because of insufficient propellant margins to reduce velocity sufficiently, so adding more mass for TPS reduces these thin margins below what's there.  Rocket equation is an exponential b!tch.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/09/2016 01:07 pm
If the thermal loading on these GTO missions is just too high to land without extensive damage, I wonder whether they would add GTO-specific TPS, or even sacrificial TPS.

Not easily done, but that's beside the point in that the loading is high because of insufficient propellant margins to reduce velocity sufficiently, so adding more mass for TPS reduces these thin margins below what's there.  Rocket equation is an exponential b!tch.
I'm thinking some sort of sprayed or painted-on sacrificial ablative TPS over those specific affected areas, to the tune of a bare fraction of a percent of the dry mass.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: envy887 on 05/09/2016 06:54 pm
Mass spent on thermal protection generally gets much better returns than mass spent on retropropulsion propellent.

Still, the JCSAT-14 stage doesn't look overly toasted in the pictures, and we know the SES-9 stage survived a hotter reentry in one piece before running out of prop.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/09/2016 07:14 pm
Mass spent on thermal protection generally gets much better returns than mass spent on retropropulsion propellent.

Still, the JCSAT-14 stage doesn't look overly toasted in the pictures, and we know the SES-9 stage survived a hotter reentry in one piece before running out of prop.
We assume SES-9 survived a hotter re-entry in one piece, but all we really know for sure is that it still had enough pieces left to keep its engines firing.

If the JCSAT return stage ends up having more thermal damage on and around its underside than expected, I could see them adding a spray-on ablative paint for GTO missions, then cleaning it off as a standard part of refurbishment.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 05/09/2016 10:16 pm

If the JCSAT return stage ends up having more thermal damage on and around its underside than expected, I could see them adding a spray-on ablative paint for GTO missions, then cleaning it off as a standard part of refurbishment.

I've held for quite awhile now that the sharply-defined discolored area around the lower part of the stage is more than simple soot deposition. I think it's either an ablative coating (or paint, serving effectively the same purpose), or some other kind of TPS. In fact, closeup photos of the CRS-8 stage following recovery look quite a bit like cork (which has been used as TPS on spacecraft in the past); if so, perhaps the darkening is actually cork scorching a bit.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Fluke72 on 05/09/2016 10:30 pm

If the JCSAT return stage ends up having more thermal damage on and around its underside than expected, I could see them adding a spray-on ablative paint for GTO missions, then cleaning it off as a standard part of refurbishment.

I've held for quite awhile now that the sharply-defined discolored area around the lower part of the stage is more than simple soot deposition. I think it's either an ablative coating (or paint, serving effectively the same purpose), or some other kind of TPS. In fact, closeup photos of the CRS-8 stage following recovery look quite a bit like cork (which has been used as TPS on spacecraft in the past); if so, perhaps the darkening is actually cork scorching a bit.

give this guy a cigar!!! 
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 05/09/2016 10:36 pm

If the JCSAT return stage ends up having more thermal damage on and around its underside than expected, I could see them adding a spray-on ablative paint for GTO missions, then cleaning it off as a standard part of refurbishment.

I've held for quite awhile now that the sharply-defined discolored area around the lower part of the stage is more than simple soot deposition. I think it's either an ablative coating (or paint, serving effectively the same purpose), or some other kind of TPS. In fact, closeup photos of the CRS-8 stage following recovery look quite a bit like cork (which has been used as TPS on spacecraft in the past); if so, perhaps the darkening is actually cork scorching a bit.

give this guy a cigar!!! 

I'll take some LIKES for my post instead. ;)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/09/2016 11:05 pm

If the JCSAT return stage ends up having more thermal damage on and around its underside than expected, I could see them adding a spray-on ablative paint for GTO missions, then cleaning it off as a standard part of refurbishment.

I've held for quite awhile now that the sharply-defined discolored area around the lower part of the stage is more than simple soot deposition. I think it's either an ablative coating (or paint, serving effectively the same purpose), or some other kind of TPS. In fact, closeup photos of the CRS-8 stage following recovery look quite a bit like cork (which has been used as TPS on spacecraft in the past); if so, perhaps the darkening is actually cork scorching a bit.
I concur. The line at the top is far too sharply defined to be merely the result of some sort of thermal effect from the oxygen tank.

My guess is that the lower third of the stage has an ablative paint while the engine panels themselves are covered with cork layers. I was watching the processing of CRS-8 and I could have sworn I saw them peel off something that was black on the outside but tan on the tear surface.

If the damage to the underside of JCSAT-14 is too great then they might add more of the same.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: somepitch on 05/10/2016 12:52 am
I wonder how many stages will have to come back for the groundhog day-like soot line debate to be put to rest...  ;D :o
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 05/10/2016 12:53 am
I wonder how many stages will have to come back for the groundhog day-like soot line debate to be put to rest...  ;D :o

I think the debate - such as it is - has been put to rest.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: gongora on 05/10/2016 03:57 am
The last 17 (now 18) posts in this thread have nothing to do with the Thaicom-8 mission.  This is a mission specific thread.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lar on 05/10/2016 03:59 am
The last 17 (now 18) posts in this thread have nothing to do with the Thaicom-8 mission.  This is a mission specific thread.
Good point. So scattered I don't see where to move them to easily.

Don't forget to report to moderators....
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ben the Space Brit on 05/10/2016 01:54 pm
Question: Has the order of missions been changed or is Thaicom-8 still scheduled to launch after the Eutelsat/Asia Broadcast pair? Forgive me if I've missed an announcement at any point.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: macpacheco on 05/10/2016 02:02 pm
Question: Has the order of missions been changed or is Thaicom-8 still scheduled to launch after the Eutelsat/Asia Broadcast pair? Forgive me if I've missed an announcement at any point.
Thaicom is expected to launch this month. Eutelsat/Asia Broadcast planned for June. There was an inversion in order.
spacexstats suggest Thaicom-8 launch in May, 26th.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: atsf90east on 05/10/2016 03:42 pm
The current launch date and time for Thaicom-8 is May 26th at 2140 GMT (5:40 p.m. EDT) from SLC-40.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: deadshot462 on 05/10/2016 08:48 pm
Apparently the range safety system will be off for maintenance until may 27th, does that conflict with this launch date or will the maintenance occur at a different time?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: wannamoonbase on 05/10/2016 09:53 pm
Apparently the range safety system will be off for maintenance until may 27th, does that conflict with this launch date or will the maintenance occur at a different time?

I've wondered about that, seems like a rather obvious over lap. But SpaceX seems to slip at least 1-2 days from the first stated goal.

I might-could be on the space-coast for the 27th. 

After seeing Delta 2's, Atlas 2,3,5's and the space shuttle it would be something to catch an F9 launch. 
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: atsf90east on 05/13/2016 08:07 pm
I know that the payload, fairing, and the Falcon 9 first stage booster are at CCAFS, but has anyone seen the second stage yet?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rpapo on 05/14/2016 11:08 am
I know that the payload, fairing, and the Falcon 9 first stage booster are at CCAFS, but has anyone seen the second stage yet?
Do we ever see second stages on the road?  I can't recall it being reported up to now.  First stages, legs, and payloads, yes.  But fairings and second stages I can't recall them being reported here before.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mader Levap on 05/14/2016 07:15 pm
Do we ever see second stages on the road?  I can't recall it being reported up to now.  First stages, legs, and payloads, yes.  But fairings and second stages I can't recall them being reported here before.
This is because of size. They are easier to overlook. Just another big load on just another trailer.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: philw1776 on 05/18/2016 12:05 am
The current launch date and time for Thaicom-8 is May 26th at 2140 GMT (5:40 p.m. EDT) from SLC-40.

This has been the quietist chatter pre-launch for any recent launch.
Something's afoot.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: tleski on 05/18/2016 12:09 am
KSC visitor center removed the launch from their schedule. I asked them why on tweeter, no reply yet. I am not sure they would be authorized to discuss this publicly even if they knew something. I guess we will find out soon enough.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: wannamoonbase on 05/18/2016 12:14 am
The current launch date and time for Thaicom-8 is May 26th at 2140 GMT (5:40 p.m. EDT) from SLC-40.

This has been the quietist chatter pre-launch for any recent launch.
Something's afoot.

I've been thinking the same thing. 

Maybe the return of the previous booster distracted people, or few of us believe the date is real.  If the static fire actually happens Sunday I'm sure we'll be back to the normal chaos next week.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Bubbinski on 05/18/2016 12:29 am
For what it's worth I checked Spaceflightnow.com's launch schedule and it still shows Thaicom as on for the 26th. No recent tweets about it from Elon or SpaceX either. But kennedyspacecenter.com shows the next launch in 17 days and being the D4H, shows only the Osiris Rex as the next one after that.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: The Amazing Catstronaut on 05/18/2016 10:06 am
Which is the most reliable source most of the time?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: FutureSpaceTourist on 05/18/2016 10:26 am
Which is the most reliable source most of the time?

I'd say SpaceX's Facebook posting on Monday, saying next launch in about 10 days, is more reliable.

As we know SpaceX launches can slip a small number of days until quite close to the launch but clearly SpaceX think they're pretty much on track. Maybe there's a day or so of slip that prompted the KSC web update, but Chris usually hears about such things and no updates from him yet.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: tleski on 05/18/2016 12:57 pm
KSC visitor center removed the launch from their schedule. I asked them why on tweeter, no reply yet. I am not sure they would be authorized to discuss this publicly even if they knew something. I guess we will find out soon enough.

Here is what KSC Visitor Center replied to my question.

https://twitter.com/explorespaceksc/status/732893554285129728
ExploreSpaceKSC: @tleski @TheFavoritist SpaceX has not confirmed official date. We're waiting to hear.


Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Toastmastern on 05/18/2016 01:12 pm
KSC visitor center removed the launch from their schedule. I asked them why on tweeter, no reply yet. I am not sure they would be authorized to discuss this publicly even if they knew something. I guess we will find out soon enough.

Here is what KSC Visitor Center replied to my question.

https://twitter.com/explorespaceksc/status/732893554285129728
ExploreSpaceKSC: @tleski @TheFavoritist SpaceX has not confirmed official date. We're waiting to hear.

Makes sense since we haven't heard anything other then around 10 days from SpaceX and this means that ExploreSpaceKSC hasn't heard anything we haven't which is a good thing in my mind :)

//Toastmastern
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mn on 05/18/2016 02:18 pm
from update thread

Static Fire is May 22 on the last schedule update. Will keep an eye on any changes (as always). We're still at May 26 NET until I'm sent an updated schedule showing a change.

The Range is currently under pre-scheduled maintenance of course. There may be rumors and such in the meantime, but we have the discussion thread for that. A documented change will go in here so that people planning to go to this launch - who usually have this thread on "notification" get to know about it.

So the eastern range is also under maintenance?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Toastmastern on 05/18/2016 02:29 pm
from update thread

Static Fire is May 22 on the last schedule update. Will keep an eye on any changes (as always). We're still at May 26 NET until I'm sent an updated schedule showing a change.

The Range is currently under pre-scheduled maintenance of course. There may be rumors and such in the meantime, but we have the discussion thread for that. A documented change will go in here so that people planning to go to this launch - who usually have this thread on "notification" get to know about it.

So the eastern range is also under maintenance?

Yea until the 27th officially but I don't think we are 100% sure that they need all that time. If things run smoothly they might be able to open up the range earlier and that might be what SpaceX are waiting for. To see if all the maintance goes as planned.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: yokem55 on 05/18/2016 05:13 pm
from update thread

Static Fire is May 22 on the last schedule update. Will keep an eye on any changes (as always). We're still at May 26 NET until I'm sent an updated schedule showing a change.

The Range is currently under pre-scheduled maintenance of course. There may be rumors and such in the meantime, but we have the discussion thread for that. A documented change will go in here so that people planning to go to this launch - who usually have this thread on "notification" get to know about it.

So the eastern range is also under maintenance?

Yea until the 27th officially but I don't think we are 100% sure that they need all that time. If things run smoothly they might be able to open up the range earlier and that might be what SpaceX are waiting for. To see if all the maintance goes as planned.
Can they still do the static fire if the range is closed?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mike_1179 on 05/18/2016 05:15 pm
Are range assists needed for a static fire?

edit: ninja'd
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Toastmastern on 05/18/2016 05:50 pm
from update thread

Static Fire is May 22 on the last schedule update. Will keep an eye on any changes (as always). We're still at May 26 NET until I'm sent an updated schedule showing a change.

The Range is currently under pre-scheduled maintenance of course. There may be rumors and such in the meantime, but we have the discussion thread for that. A documented change will go in here so that people planning to go to this launch - who usually have this thread on "notification" get to know about it.

So the eastern range is also under maintenance?

Yea until the 27th officially but I don't think we are 100% sure that they need all that time. If things run smoothly they might be able to open up the range earlier and that might be what SpaceX are waiting for. To see if all the maintance goes as planned.
Can they still do the static fire if the range is closed?

I've never heard them scrub a static fire due to range issues
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jim on 05/18/2016 06:52 pm

I've never heard them scrub a static fire due to range issues

it isn't a scrub, it is a postponement.  Scrubs only occur once in a countdown.  And yes, static fires require range assets.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Toastmastern on 05/18/2016 07:21 pm

I've never heard them scrub a static fire due to range issues

it isn't a scrub, it is a postponement.  Scrubs only occur once in a countdown.  And yes, static fires require range assets.

Yea I meant as a range scrub during the countdown.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lar on 05/18/2016 08:18 pm

I've never heard them scrub a static fire due to range issues

it isn't a scrub, it is a postponement.  Scrubs only occur once in a countdown.  And yes, static fires require range assets.
Do they require some but not as many as a launch? All the same assets? It varies by provider because "It depends on the fidelity" of the static fire to the actual mission? Something else?

If less, what kind of assets do they require? Thanks!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Space Ghost 1962 on 05/19/2016 11:22 pm
A static fire is a launch without a launch. Since its a launch, it requires the range assets, as they are an integral part of a launch.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rpapo on 05/20/2016 10:13 am
This is 21 nmi away from its position for the JCSAT-14 landing.
Closer, or further?  As we saw from JCSAT, even four miles makes a significant difference in how hot the reentry can be.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mike_1179 on 05/20/2016 10:18 am
But which ones specifically? Tracking antennas, FTS equipment, patrols to tell people to get their boats out of there?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Kabloona on 05/20/2016 10:18 am
This is 21 nmi away from its position for the JCSAT-14 landing.
Closer, or further?  As we saw from JCSAT, even four miles makes a significant difference in how hot the reentry can be.

Thaicom-8 ASDS position is about 10 nmi farther from the Cape, and 11 nmi from its JCSAT-14 position. Earlier post on Updates thread now edited with corrections.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: alang on 05/20/2016 12:03 pm
Do we know for a fact to what extent thrust is directly opposite to the direction of travel on reentry? It could be they are experimenting with various angles of thrust to change the path of the stage so it slows down in different density air.
Intuitively it seems to me that the kind of aerodynamic angle of attack that would keep the stage higher is also the kind of angle that would be more suitable for reducing horizontal velocity by the engines, so these two effects could work in difficult combinations.
This must have been discussed at length on this site.

Edit: removed quote.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: vulture4 on 05/20/2016 10:26 pm
A static fire is a launch without a launch. Since its a launch, it requires the range assets, as they are an integral part of a launch.
A static fire is not the same as a dress rehearsal or simulation. Clearance is needed for any hazardous operation but I have never heard of the actual range assets required for a launch being also required for a static fire.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: deruch on 05/21/2016 05:25 am
A static fire is a launch without a launch. Since its a launch, it requires the range assets, as they are an integral part of a launch.
A static fire is not the same as a dress rehearsal or simulation. Clearance is needed for any hazardous operation but I have never heard of the actual range assets required for a launch being also required for a static fire.

Well, Jim just said otherwise above.  But in addition, there are NTMs posted for the static fires and area clearances.  Plus, I believe you're wrong about it not being a "dress rehearsal".  Part of the reason SpaceX is doing them is to make sure that everything is online and in working order in preparation for the launch attempt.  They may not be actively using the range assets, but I would bet the assets get their check-out done just like they would in the launch countdown.  Plus it gives the personnel an additional opportunity to train for their mission.  Why wouldn't they use it?  Anyways, as an uninvolved observer, I'll leave it to one of the posters with firsthand knowledge to give a definitive answer (I'm taking Jim's as such).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jim on 05/21/2016 01:49 pm
A static fire is a launch without a launch. Since its a launch, it requires the range assets, as they are an integral part of a launch.
A static fire is not the same as a dress rehearsal or simulation. Clearance is needed for any hazardous operation but I have never heard of the actual range assets required for a launch being also required for a static fire.

Beacon checks which SX has done during WDR's and Static fire uses range assets. 
But also at a minimum, there are comm links, security personnel, generator support, blast/toxic vapor monitoring, etc besides radars.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: kdhilliard on 05/22/2016 03:13 pm
From the update thread:
Patrick AFB has the launch Thursday, May 26 at 5:40 p.m. EST (i.e. 6:40 p.m. EDT)
http://www.patrick.af.mil/

That's got to be a typo on their part.  Launch time is 5:40 EDT (21:40 UTC).

If anyone here knows someone with Patrick AFB who can contact their webmaster about correcting that, they should also let them know that their "Contact Us" form is broken.  At least today it is offering a choice (albeit the single one "Directory Assistance") under the "Recipient" field (yesterday there were no options there and it wouldn't accept a message without one), but now it is complaining that the "captcha information does not appear to be valid" despite the reCAPTCHA checking off green.

~Kirk

Edit: Thanks for the suggestion, Gene.  I've emailed 45th SW PA office about the typo.
Edit2: I've received an email back from they saying that it has been fixed.  It now shows "Launch Time: 5:40 p.m. ET".  (May require a browser refresh.)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: GeneBelcher on 05/22/2016 03:47 pm
From the update thread:
Patrick AFB has the launch Thursday, May 26 at 5:40 p.m. EST (i.e. 6:40 p.m. EDT)
http://www.patrick.af.mil/

That's got to be a typo on their part.  Launch time is 5:40 EDT (21:40 UTC).

If anyone here knows someone with Patrick AFB who can contact their webmaster about correcting that, they should also let them know that their "Contact Us" form is broken.  At least today it is offering a choice (albeit the single one "Directory Assistance") under the "Recipient" field (yesterday there were no options there and it wouldn't accept a message without one), but now it is complaining that the "captcha information does not appear to be valid" despite the reCAPTCHA checking off green.

~Kirk

You can try calling their Public Affairs number and see if they can help. http://www.patrick.af.mil/About-Us/Fact-Sheets/Article/329838/45th-space-wing-staff-agencies
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rockets4life97 on 05/22/2016 05:52 pm
Any news on whether the Falcon 9 is rolling out to the pad for a static fire either today or tomorrow?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: The Roadie on 05/22/2016 06:32 pm
If anyone here knows someone with Patrick AFB who can contact their webmaster about correcting that, they should also let them know that their "Contact Us" form is broken.  At least today it is offering a choice (albeit the single one "Directory Assistance") under the "Recipient" field (yesterday there were no options there and it wouldn't accept a message without one), but now it is complaining that the "captcha information does not appear to be valid" despite the reCAPTCHA checking off green.
Just messaged a weather office leader I know, who acknowledged receipt.

ADDED: He'll get the EDT thing fixed ASAP. The "contact me" form was broken by a push update from the AF to everybody, and they have no control to fix it. Been reported upstream.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mark K on 05/22/2016 08:29 pm
FloridaToday reports static fire might happen on Monday - one day later then expected.

from this thread above in April:
Static Fire now May 23 (Florida Today). No change to NET launch date.

So May 23rd is not a change - was announced last month.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: pospa on 05/22/2016 08:52 pm
FloridaToday reports static fire might happen on Monday - one day later then expected.
from this thread above in April:
Static Fire now May 23 (Florida Today). No change to NET launch date.
So May 23rd is not a change - was announced last month.

But later on 5/18 Chris announced this:

Static Fire is May 22 on the last schedule update. Will keep an eye on any changes (as always)....
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Flying Beaver on 05/22/2016 08:59 pm
FloridaToday reports static fire might happen on Monday - one day later then expected.

from this thread above in April:
Static Fire now May 23 (Florida Today). No change to NET launch date.

So May 23rd is not a change - was announced last month.

Note that Chris edited the first post in this thread 5 hours ago to mirror the new info released by Florida Today. ;)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sanman on 05/24/2016 01:00 am
2 launches only 2.5 weeks apart - is this the record for closely spaced space launches?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Bubbinski on 05/24/2016 01:02 am
Say, any word on the static fire today? It's now past 9 pm in FL
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meberbs on 05/24/2016 01:10 am
2 launches only 2.5 weeks apart - is this the record for closely spaced space launches?
SpaceX did 2 launches in 2 weeks before (September 7 and 21, 2014)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris Bergin on 05/24/2016 01:38 am
Say, any word on the static fire today? It's now past 9 pm in FL

You're tempting me into a Jim style answer.

No.  :P

Radio silence from the Cape for the past few hours. I don't think anyone's even spotted her on the pad. Of course, the second I post this, you know what'll happen ;)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: atsf90east on 05/24/2016 02:00 am
I can't tell you my source, but I was told that the Hot Fire was never supposed to happen tonight.  I'd keep an eye on LC-40 tomorrow though ;)  Not everything you see in the media is official.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris Bergin on 05/24/2016 02:10 am
I can't tell you my source, but I was told that the Hot Fire was never supposed to happen tonight.  I'd keep an eye on LC-40 tomorrow though ;)  Not everything you see in the media is official.


For what it's worth I've got a support plan sheet we get in L2 (not SpaceX, but the Cape) and that now has the 24th as the static fire on the updated sheet....

Going to be tight if they can't get it done tomorrow afternoon ish.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: toruonu on 05/24/2016 06:38 am
Going to be tight if they can't get it done tomorrow afternoon ish.

Maybe they'll just do the static fire at the start of the launch window, recycle and go for launch if it was good :D
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: yokem55 on 05/24/2016 08:00 pm
Going to be tight if they can't get it done tomorrow afternoon ish.

Maybe they'll just do the static fire at the start of the launch window, recycle and go for launch if it was good :D
I don't think that will happen this time, but I would not be surprised if that eventually becomes the flow. This assumes they can rapidly assess the data from the static fire and and make a go/no-go decision in time to recycle for the actual launch. Why waste time trucking the vehicle in and out of the hanger?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: AncientU on 05/24/2016 08:05 pm
Say, any word on the static fire today? It's now past 9 pm in FL

4PM in Florida now, not 9.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mheney on 05/24/2016 08:17 pm
Say, any word on the static fire today? It's now past 9 pm in FL

4PM in Florida now, not 9.
Bubbinski's post was last night - wondering about a Monday static fire.  (didn't happen, obviously).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: The Roadie on 05/24/2016 09:06 pm
I don't think that will happen this time, but I would not be surprised if that eventually becomes the flow.
Densified propellant warm-up will be one of many things making that an unlikely goal.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Okie_Steve on 05/24/2016 09:19 pm
Maybe that's why they wanted two tankfulls of LOX capacity ;D
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lar on 05/24/2016 09:21 pm
I don't think that will happen this time, but I would not be surprised if that eventually becomes the flow.
Densified propellant warm-up will be one of many things making that an unlikely goal.
Maybe for BFR? if they don't need to tweak every last bit of performance?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: wannamoonbase on 05/24/2016 09:23 pm
Maybe that's why they wanted two tankfulls of LOX capacity ;D

Terrible idea, what happens if you need to cycle for the real attempt?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Retired Downrange on 05/24/2016 09:40 pm
some bad weather may affect the ASDS :

SPECIAL TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
335 PM EDT TUE MAY 24 2016

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

An area of showers and thunderstorms over the western Atlantic Ocean
near and northeast of the Bahamas is associated with the
interaction of an upper-level trough and a weakening cold front.
While development is not expected for the next couple of days,
environmental conditions could become more conducive for some
tropical or subtropical development by Friday. This area of
disturbed weather is expected to move slowly west-northwestward or
northwestward and gradually approach the southeastern United
States over the next few days. The next Special Tropical Weather
Outlook will be issued by 4 PM EDT Wednesday.
* Formation chance through 48 hours...low...near 0 percent
* Formation chance through 5 days...low...30 percent

$$
Forecaster Blake

http://www.nhc.noaa.gov/text/refresh/MIATWOAT+shtml/241935_MIATWOAT.shtml


Go here to see the Satellite infrared image of the weather
http://weather.msfc.nasa.gov/GOES/goeseasthurrir.html
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: OnWithTheShow on 05/25/2016 01:10 am
<sarcasm> But there cant be a static fire today! The range is closed for maintenance! </sarcasm>  :o
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Wolfram66 on 05/25/2016 01:30 am
this is a great place to see tropical development http://tropic.ssec.wisc.edu/
http://nhc.noaa.gov

and for detailed wind and shear use this link http://www.spc.noaa.gov/
http://www.spc.noaa.gov/exper/sref/ for gif sequence of Wind and shear
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris Bergin on 05/25/2016 01:34 am
So we're just standing by now. I'm sure if SpaceX tweet anything I'll get beaten to the punch by someone posting it before me...so go for it when you see it. ;)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lar on 05/25/2016 01:43 am
We still love you anyway.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Darga on 05/25/2016 02:33 am
and complete https://vine.co/v/i9bHDtOgmFi
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Wolfram66 on 05/25/2016 02:44 am
https://mobile.twitter.com/SpaceX/status/735297300491325440
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rosbif73 on 05/25/2016 06:01 am
Maybe that's why they wanted two tankfulls of LOX capacity ;D

Terrible idea, what happens if you need to cycle for the real attempt?

Maybe add a third tankful then ;-)

More seriously, how soon after the static fire would it be feasible to launch? Do we know how long it takes them to analyse the data and give the go-ahead for launch? What constraints would there be (other than LOX temperature already mentioned) to stop them launching almost immediately? The idea of doing the static fire shortly before the start of the launch window, leaving the rocket on the pad and launching just a few hours later certainly seems (on the face of it, at least to a non-specialist like me) like it ought to be a worthwhile pad flow optimisation.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: LouScheffer on 05/25/2016 01:35 pm
Thaicom-8 ASDS position is about 10 nmi farther from the Cape, and 11 nmi from its JCSAT-14 position. Earlier post on Updates thread now edited with corrections.
I think this means they must be experimenting with a different trajectory.

Suppose SpaceX reserves the same entry/landing fuel they did for JCSAT, which seems about the minimum possible.  Then reducing the payload to 3.1t from 4.7t adds an extra 20 m/s at first stage cutoff (assumptions 394t fuel, 29t empty mass of stage 1, 18.5t reserved for landing, second stage 120t + payload).  Since the stage coasts for about 500 seconds before the re-entry burn, that puts it at most 10 km downrange.

However, the ship position is about 16 km downrange.  And if they reserve more fuel to make the re-entry less damaging, the discrepancy gets even worse, since more fuel reserved implies less final V and a shorter landing.

So my guess here is that they are experimenting with a more depressed trajectory.  This would be more efficient, since more of your V is in the intended final direction.  But perhaps the limiting factor is the need to turn the stage around with the relatively weak cold-gas thrusters, which may not be possible if the atmosphere is too dense.  But maybe the previous flights revealed enough margin to try a lower staging.

Or possibly (and this is complete speculation) if the aero forces are too big for the cold-gas thrusters, then maybe they are enough so you could deploy them right after staging to help turn the stage around. 
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Kabloona on 05/25/2016 03:55 pm
Quote
But perhaps the limiting factor is the need to turn the stage around with the relatively weak cold-gas thrusters, which may not be possible if the atmosphere is too dense.  But maybe the previous flights revealed enough margin to try a lower staging.

Or possibly (and this is complete speculation) if the aero forces are too big for the cold-gas thrusters, then maybe they are enough so you could deploy them right after staging to help turn the stage around.

That shouldn't be an issue. On JCSAT-14, MECO happened around 67 km, and the stage continues coasting up to ballistic apogee (on the hosted webcast they said apogee was around 200 km), so there's plenty of time to re-orient in low density atmosphere.

Quote
Since the stage coasts for about 500 seconds before the re-entry burn, that puts it at most 10 km downrange.

The coast on JCSAT-14 was only about 245 seconds, just a little over 4 minutes. So the extra delta V helps even less, only 5 km or so at most.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: bstrong on 05/25/2016 04:00 pm
Maybe that's why they wanted two tankfulls of LOX capacity ;D

Terrible idea, what happens if you need to cycle for the real attempt?

Maybe add a third tankful then ;-)

More seriously, how soon after the static fire would it be feasible to launch? Do we know how long it takes them to analyse the data and give the go-ahead for launch? What constraints would there be (other than LOX temperature already mentioned) to stop them launching almost immediately? The idea of doing the static fire shortly before the start of the launch window, leaving the rocket on the pad and launching just a few hours later certainly seems (on the face of it, at least to a non-specialist like me) like it ought to be a worthwhile pad flow optimisation.

According to Jim, the static fire is going away, which is an even better pad flow optimization:

https://forum.nasaspaceflight.com/index.php?topic=39181.msg1528887#msg1528887
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: wannamoonbase on 05/25/2016 04:31 pm
According to Jim, the static fire is going away, which is an even better pad flow optimization:

https://forum.nasaspaceflight.com/index.php?topic=39181.msg1528887#msg1528887

Good, that will be awesome when it happens.  A real sign of SpaceX and the vehicle maturing plus it will reduce costs as well.

Edit: Maybe required to go from a consistent 3 week to consistent 2 week launch cadence.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: LouScheffer on 05/25/2016 05:00 pm
Quote
But perhaps the limiting factor is the need to turn the stage around with the relatively weak cold-gas thrusters, which may not be possible if the atmosphere is too dense.  But maybe the previous flights revealed enough margin to try a lower staging.

Or possibly (and this is complete speculation) if the aero forces are too big for the cold-gas thrusters, then maybe they are enough so you could deploy them [the grid fins]  right after staging to help turn the stage around.

That shouldn't be an issue. On JCSAT-14, MECO happened around 67 km, and the stage continues coasting up to ballistic apogee (on the hosted webcast they said apogee was around 200 km), so there's plenty of time to re-orient in low density atmosphere.
But they don't seem to wait for the lowest density air - they re-orient right after separation.  If you are doing boost-back, this makes sense - you want to reverse your down-range velocity as quickly as possible.  But if they are just doing a re-entry burn, they could in theory wait until the top of the arc, but they don't.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: LouScheffer on 05/25/2016 05:51 pm
Thaicom-8 ASDS position is about 10 nmi farther from the Cape, and 11 nmi from its JCSAT-14 position. Earlier post on Updates thread now edited with corrections.
So my guess here is that they are experimenting with a more depressed trajectory.  [...] 
Oops, my error, this is backwards.  Since the trajectory is at an angle of less than 45 degrees from the horizontal (roughly 2100 m/s horizontal and 940 m/s vertical), depressing the trajectory makes it land shorter (more horizontal v, but less time in flight since less vertical v).  To make it land longer, it needs to be lofted a little more. 
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Arb on 05/25/2016 06:07 pm
According to Jim, the static fire is going away, which is an even better pad flow optimization:

https://forum.nasaspaceflight.com/index.php?topic=39181.msg1528887#msg1528887

Good, that will be awesome when it happens.  A real sign of SpaceX and the vehicle maturing plus it will reduce costs as well.

Edit: Maybe required to go from a consistent 3 week to consistent 2 week launch cadence.
Often hard with Jim's posts to distinguish opinion from inside knowledge, particularly when he talks about SpaceX.[1] Unless he states a source it's arguably best to assume opinion and believe it when it happens.

[1] Historic information is clearly a different matter. He knows his stuff.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: bstrong on 05/25/2016 06:20 pm
According to Jim, the static fire is going away, which is an even better pad flow optimization:

https://forum.nasaspaceflight.com/index.php?topic=39181.msg1528887#msg1528887

Good, that will be awesome when it happens.  A real sign of SpaceX and the vehicle maturing plus it will reduce costs as well.

Edit: Maybe required to go from a consistent 3 week to consistent 2 week launch cadence.
Often hard with Jim's posts to distinguish opinion from inside knowledge, particularly when he talks about SpaceX.[1] Unless he states a source it's arguably best to assume opinion and believe it when it happens.

[1] Historic information is clearly a different matter. He knows his stuff.

Hopefully Jim will chime in here, but based on the discussion that followed the linked post, I'm pretty sure this one was not an opinion. He did also state that he didn't know whether they might still do static fires on reused cores.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Kabloona on 05/25/2016 09:19 pm
Thaicom-8 ASDS position is about 10 nmi farther from the Cape, and 11 nmi from its JCSAT-14 position. Earlier post on Updates thread now edited with corrections.
So my guess here is that they are experimenting with a more depressed trajectory.  [...] 
Oops, my error, this is backwards.  Since the trajectory is at an angle of less than 45 degrees from the horizontal (roughly 2100 m/s horizontal and 940 m/s vertical), depressing the trajectory makes it land shorter (more horizontal v, but less time in flight since less vertical v).  To make it land longer, it needs to be lofted a little more.

The mission timeline was just released and MECO is now at 2:35, vs 2:38 for JCSAT-14, so 3 seconds earlier, FWIW.

Saving a few seconds of propellant for a longer entry burn? All other things being equal, 3 seconds off a stage 1 full thrust burn equals 9 more seconds of entry burn.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: LouScheffer on 05/25/2016 11:51 pm
The mission timeline was just released and MECO is now at 2:35, vs 2:38 for JCSAT-14, so 3 seconds earlier, FWIW.

Saving a few seconds of propellant for a longer entry burn? All other things being equal, 3 seconds off a stage 1 full thrust burn equals 9 more seconds of entry burn.
That would be my guess.  At burnout, the first stage is accelerating at about 42 m/s, so 3 sec less costs 126 m/s.  They get about 20 m/s of this back from higher performance of the first stage because of the lighter payload, for a net loss of about 100 m/s.  However, the second stage gains about 600 m/s with a payload that's 3.1t instead of 4.7t.  So overall they gain 500 m/s over JCSAT.  Presumably they will use this for a high apogee (min delta V remaining) or by reducing the inclination as much as possible (if the customer prefers apogee at GEO for simplicity).

Once the second stage departs, a 3 engine burn will decelerate the stage at about 46 m/s (assuming a 29t empty mass and 24t of fuel reserved). Over 9 seconds that will drop the speed by more than 400 m/s.   That makes re-entry more than one Mach number gentler. Since energy goes like the square, and peak heating like the cube (of velocity) this should result in a gently-used stage.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: macpacheco on 05/26/2016 12:20 am
The mission timeline was just released and MECO is now at 2:35, vs 2:38 for JCSAT-14, so 3 seconds earlier, FWIW.

Saving a few seconds of propellant for a longer entry burn? All other things being equal, 3 seconds off a stage 1 full thrust burn equals 9 more seconds of entry burn.
Given the substantially lighter payload mass, wouldn't this still give the payload a higher DeltaV towards orbit (including more substantially higher DeltaV S2 can achieve with a lighter payload) ?

Could this be a super sync payload delivery + gentler re-entry burn ?


I'm in the camp that the landing burn isn't the issue. SpaceX knows their structural margins, computers make corrections in micro seconds and the last second landing burn reduces exposure to varying winds in the last minute of flight before landing. So I think that a 3 engine landing will be standard from now on.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Kabloona on 05/26/2016 12:25 am
Quote
Given the substantially lighter payload mass, wouldn't this still give the payload a higher DeltaV towards orbit (including more substantially higher DeltaV S2 can achieve with a lighter payload) ?

LouScheffer just answered that question nicely with numbers in the post above yours. In a word, yes.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/26/2016 12:30 am
Quote
Given the substantially lighter payload mass, wouldn't this still give the payload a higher DeltaV towards orbit (including more substantially higher DeltaV S2 can achieve with a lighter payload) ?

LouScheffer just answered that question in the post above yours.

In a weird case of prescience, it would seem :P

But yeah, LouScheffer's analysis was spot on.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: oiorionsbelt on 05/26/2016 04:54 am
The folded Falcon legs, the upper talons of the Transporter Erector, pave the way for Raptors to Mars.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: dorkmo on 05/26/2016 05:08 am
could it be this engine from 40 weeks ago?

https://www.instagram.com/p/6gYIwJl8ZH/
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/26/2016 05:09 am
Looks like there is a used engine with a white stripe tracking pattern painted on (spotted by Reddit user JM93)
Possible reused engine from OG2 or CRS-8 core?

Very interesting.

But why would they visually mark it? I'm sure they can track which engine is which.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: dorkmo on 05/26/2016 05:15 am
perhaps they were doing some nondestructive testing on the one they painted black and only removed the paint where they needed to test.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/26/2016 05:22 am
Yes, these stripes (and I definitely think they're not reflections) are not visual markings; they must have a physical function, and probably something they intend to inspect after landing and recovery of the stage. But what kind of experiment would they fly in an actual commercial launch?

I admit I'm completely puzzled. And I was about to go to bed, dammit.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: biosehnsucht on 05/26/2016 06:14 am
Perhaps so they can check on a single engine the effect that the thermal coating has vs uncoated engine (rather than comparing different engines which may not have experienced completely identical conditions) ?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: pospa on 05/26/2016 07:12 am
Looks like there is a used engine with a white stripe tracking pattern painted on

Test as you fly, fly as you test, dear Watson.  ;)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: MP99 on 05/26/2016 08:13 am
Maybe that's why they wanted two tankfulls of LOX capacity ;D

Terrible idea, what happens if you need to cycle for the real attempt?
When NASA did tests on subcooled propellants, they loaded the tank at boiling point, then circulated prop out and back into the tank to subcool it.

This relied on the tank contents staying stratified, but meant they could extract warmer prop from the top of the tank and inject cold prop at the tank bottom.

In this way they could remove heat from the tank without having to replace the whole contents - only that which convected up the tank walls and collected at the top.

Cheers, Martin
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: The Amazing Catstronaut on 05/26/2016 10:21 am
Yes, these stripes (and I definitely think they're not reflections) are not visual markings; they must have a physical function, and probably something they intend to inspect after landing and recovery of the stage. But what kind of experiment would they fly in an actual commercial launch?

I admit I'm completely puzzled. And I was about to go to bed, dammit.

A visual cue is still valuable on a logistics level - it can save a few minutes if there's ever any confusion, yet I agree that it doesn't sit right for something so superficial. Hrm.

Will those stripes survive the entire launch/re-entry process? if not, then you can assume they have no in-flight functionality.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rpapo on 05/26/2016 10:41 am
Yes, these stripes (and I definitely think they're not reflections) are not visual markings; they must have a physical function, and probably something they intend to inspect after landing and recovery of the stage. But what kind of experiment would they fly in an actual commercial launch?

I admit I'm completely puzzled. And I was about to go to bed, dammit.

A visual cue is still valuable on a logistics level - it can save a few minutes if there's ever any confusion, yet I agree that it doesn't sit right for something so superficial. Hrm.

Will those stripes survive the entire launch/re-entry process? if not, then you can assume they have no in-flight functionality.
Worse: If those stripes are indeed real, and are indeed some sort of paint, then that paint needs to be very conductive and emissive if it is not to affect the engine bell's temperature distribution.

That's forgetting about whether or not paint can survive at all...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: LouScheffer on 05/26/2016 11:31 am
Looks like there is a used engine with a white stripe tracking pattern painted on (spotted by Reddit user JM93)
Possible reused engine from OG2 or CRS-8 core?
My guess is that this a thermal tell-tale on an engine that is not firing during re-entry.  The outer surface of the firing engines can't get hotter than the boiling point of kerosene. but the non-firing engines might.  Also, this is a hard place to put a thermocouple or other temperature measuring device.  So perhaps this a temperature-sensitive paint that they will inspect after (if) the booster lands.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Saabstory88 on 05/26/2016 11:44 am
Worse: If those stripes are indeed real, and are indeed some sort of paint, then that paint needs to be very conductive and emissive if it is not to affect the engine bell's temperature distribution.

That's forgetting about whether or not paint can survive at all...

Along this line, if it is in fact a re-used engine, perhaps those are the areas that require the soot to be scraped off so that the engine can cool effectively. The lines look a little uneven, so I would think the subtractive removal of something more likely than something being added unevenly. That being said, it may just as well be there new coating, and they discovered that certain areas are not cooling properly during testing, so they had to scrape off a bit there.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: vanoord on 05/26/2016 11:48 am
Along this line, if it is in fact a re-used engine, perhaps those are the areas that require the soot to be scraped off so that the engine can cool effectively. The lines look a little uneven, so I would think the subtractive removal of something more likely than something being added unevenly. That being said, it may just as well be there new coating, and they discovered that certain areas are not cooling properly during testing, so they had to scrape off a bit there.

Indeed: if you were going to go to the trouble of painting stripes onto the engine for any reason, you'd probably have the decency to use masking tape to get the edges straight.

The 'what? / why?' is a question for the post-launch presser, hopefully.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jet Black on 05/26/2016 11:54 am
Looks like there is a used engine with a white stripe tracking pattern painted on (spotted by Reddit user JM93)
Possible reused engine from OG2 or CRS-8 core?

I wonder if they are having to consider putting ablative paint on the bells due to re-entry damage
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rpapo on 05/26/2016 12:00 pm
Looks like there is a used engine with a white stripe tracking pattern painted on (spotted by Reddit user JM93)
Possible reused engine from OG2 or CRS-8 core?

I wonder if they are having to consider putting ablative paint on the bells due to re-entry damage
That would damage the ability to shed heat from the bells emissively, as most ablative materials are actually pretty good insulators too.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: francesco nicoli on 05/26/2016 12:02 pm
isn't that very risky to have a re-used engine on a commercial GEO mission? or they have 1 engine redundance?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Saabstory88 on 05/26/2016 12:24 pm
isn't that very risky to have a re-used engine on a commercial GEO mission? or they have 1 engine redundance?

The Falcon now has extra performance built in, so an engine out does not compromise the main mission even on a GTO launch. The octoweb is designed to prevent one failure from propagating to other engines. These engines have been designed from the get go to be re-used, so assuming the engine has been test fired again, then it should be good to fly. If it is indeed an engine from F9-0021, then they would have had plenty of time to make sure it was fit to fly.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: The Amazing Catstronaut on 05/26/2016 12:53 pm
Indeed - proving engine reuse would certainly go a long way to proving reuse of the whole architecture, considering that a rocket is just, y'know, engine(s) plus tanks plus avionics plus smaller engines for attitude control, separation  elements and a few other gismos.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: wannamoonbase on 05/26/2016 01:00 pm
isn't that very risky to have a re-used engine on a commercial GEO mission? or they have 1 engine redundance?

I see it being a quality issue if it was swapped after the testing at McGregor.  However, if the engine was send to Hawthorne, installed in the plant and went through the normal manufacturing and qualification process then no worries.

Same Same.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/26/2016 01:32 pm
Those stripes on the engine don't look like paint to me. I think it's reflections that make it look like paint stripes.
Don't think it is reflections.  Compare to the engine to the right, and imagine a similar reflection pattern masked by soot.  We wouldn't see clear white stripes that don't vary in intensity, like we do on the left engine.

Very interesting.  I would definitely guess a re-used engine, but what the white stripes are is a puzzle.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/26/2016 01:35 pm
isn't that very risky to have a re-used engine on a commercial GEO mission? or they have 1 engine redundance?

The Falcon now has extra performance built in, so an engine out does not compromise the main mission even on a GTO launch.
And this GTO launch in particular has a much lighter payload than the most recent GTO launches.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: JasonAW3 on 05/26/2016 01:43 pm
According to Jim, the static fire is going away, which is an even better pad flow optimization:

https://forum.nasaspaceflight.com/index.php?topic=39181.msg1528887#msg1528887

Good, that will be awesome when it happens.  A real sign of SpaceX and the vehicle maturing plus it will reduce costs as well.

Edit: Maybe required to go from a consistent 3 week to consistent 2 week launch cadence.
Often hard with Jim's posts to distinguish opinion from inside knowledge, particularly when he talks about SpaceX.[1] Unless he states a source it's arguably best to assume opinion and believe it when it happens.

[1] Historic information is clearly a different matter. He knows his stuff.

Hopefully Jim will chime in here, but based on the discussion that followed the linked post, I'm pretty sure this one was not an opinion. He did also state that he didn't know whether they might still do static fires on reused cores.

Wouldn't be surprised if they did.  If nothing else, to at least "clear the throats" as it were.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: starhawk92 on 05/26/2016 02:06 pm
isn't that very risky to have a re-used engine on a commercial GEO mission? or they have 1 engine redundance?

I see it being a quality issue if it was swapped after the testing at McGregor.  However, if the engine was send to Hawthorne, installed in the plant and went through the normal manufacturing and qualification process then no worries.

Same Same.

So, could this be the first (obvious?) reuse in a progression of components to piecewise confirm as much reflight possiblity as possible before using a complete core?  What other components are swappable?  I would assume something like an internal tank would be major surgery to a new core, but engines were made to be swapped.  What could be next, or have already gone on JCSAT-14?

And what side of the rocket is that -- or better yet, will be downrange when we are looking through the jellyfish during ascent?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Saabstory88 on 05/26/2016 02:14 pm
And what side of the rocket is that -- or better yet, will be downrange when we are looking through the jellyfish during ascent?

Using the users guide coordinate system, it would be Engine #1

Edit: The side of the vehicle facing away from the TEL, the FTS side, would be Z+
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: MarekCyzio on 05/26/2016 02:31 pm
William Graham's mission overview article:

https://www.nasaspaceflight.com/2016/05/falcon-9-thaicom-8-launch/

We also hear the LRR has passed, as expected.

While the second stage is making its first burn, the first stage will perform a series of three manoeuvres to attempt its landing.

The first of these, a boostback burn, will place it on course for the recovery drone ship.

Are you sure there is a boostback burn in this flight?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mn on 05/26/2016 02:38 pm
Looks like there is a used engine with a white stripe tracking pattern painted on (spotted by Reddit user JM93)
Possible reused engine from OG2 or CRS-8 core?

Maybe I missed something but what is the connection from the white stripes to a used engine?

Whatever reasons they have for the white stripes could just as easily apply to a new engine?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Dudely on 05/26/2016 02:41 pm
Looks like there is a used engine with a white stripe tracking pattern painted on (spotted by Reddit user JM93)
Possible reused engine from OG2 or CRS-8 core?

Maybe I missed something but what is the connection from the white stripes to a used engine?

Whatever reasons they have for the white stripes could just as easily apply to a new engine?

My thinking was that the white bits look pretty sloppy for a new engine.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: WBY1984 on 05/26/2016 02:42 pm
Looks like there is a used engine with a white stripe tracking pattern painted on (spotted by Reddit user JM93)
Possible reused engine from OG2 or CRS-8 core?

Maybe I missed something but what is the connection from the white stripes to a used engine?

Whatever reasons they have for the white stripes could just as easily apply to a new engine?
It's not entirely clear that they are white stripes, or merely areas cleared of soot from a flown engine.


Quote
My thinking was that the white bits look pretty sloppy for a new engine.
If they are 'stripes', we can only speculate as to the function. Maybe they are as neat as they need to be.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/26/2016 02:43 pm
Are you sure there is a boostback burn in this flight?

According to the Thaicom-8 reddit thread (https://www.reddit.com/r/spacex/comments/4l47wm/rspacex_thaicom_8_official_launch_discussion/), there won't be a boostback burn. It's a high-velocity launch after all (to a supersynchronous GTO, in fact).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Kabloona on 05/26/2016 02:55 pm
Looks like there is a used engine with a white stripe tracking pattern painted on (spotted by Reddit user JM93)
Possible reused engine from OG2 or CRS-8 core?
My guess is that this a thermal tell-tale on an engine that is not firing during re-entry.  The outer surface of the firing engines can't get hotter than the boiling point of kerosene. but the non-firing engines might.  Also, this is a hard place to put a thermocouple or other temperature measuring device.  So perhaps this a temperature-sensitive paint that they will inspect after (if) the booster lands.

I like the thermal telltale idea, but based on the relative position of the TEL and the nearest leg, it appears this is the #1 engine, which is one of the three engines used for the entry burn, and possibly the landing burn if they repeat the three-engine landing burn. The engine to the right of it is #2, for reference in the coordinate sketch below:

http://forum.nasaspaceflight.com/index.php?topic=39215.0

So the (possibly) multiple restarts on this engine, plus its black coating which will maximize thermal emissivity relative to the other bare metal engine nozzles, means the white stripes will see the worst heating conditions of all the nozzle surfaces, except maybe #9. So this may be some "worst case" thermal experiment. Maybe testing different formulations of SPAM to see which one holds up best? Or just trying to identify local hot spots on the nozzle.

Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: LouScheffer on 05/26/2016 03:15 pm
  At burnout, the first stage is accelerating at about 42 m/s, so 3 sec less costs 126 m/s.  They get about 20 m/s of this back from higher performance of the first stage because of the lighter payload, for a net loss of about 100 m/s.  However, the second stage gains about 600 m/s with a payload that's 3.1t instead of 4.7t.  So overall they gain 500 m/s over JCSAT.  Presumably they will use this for a high apogee (min delta V remaining) or by reducing the inclination as much as possible (if the customer prefers apogee at GEO for simplicity).

Once the second stage departs, a 3 engine burn will decelerate the stage at about 46 m/s (assuming a 29t empty mass and 24t of fuel reserved). Over 9 seconds that will drop the speed by more than 400 m/s.   That makes re-entry more than one Mach number gentler. Since energy goes like the square, and peak heating like the cube (of velocity) this should result in a gently-used stage.
Quote
Hey Lou,
     Would you mind sending me the equations you used for to figure out this?
This is all done with 3 equations:  F=MA is from basic physics.  The rocket equation is dV = Vexhaust*ln(Initial/Final), where dV is the change in velocity, Vexhaust is the speed of the escaping gas (typically computed as ISP*G, since most designers quote ISP), 'Initial' is the initial mass of the rocket, and 'final' is the final mass at burnout.  I use 9.8 m/s for G.  The 'ln' (natural log) in the rocket equation compensates for the changing mass during the burn.

The final equation that's handy is that fuel consumption = thrust/Vexhaust.   So for example, a Merlin with a thrust of 825,000 N and an ISP of 311 uses fuel at a rate of 825000/(311*9.8 )  = 270 kg/sec. 

The bigger problem is finding accurate numbers to put in - that's why I state the assumptions. I typically use first stage ISP = 311 (use the vacuum value since these burns are up high), thrust = 825,000 N, minimal landing fuel = 17.5t (270 kg/sec * (15 sec(3 engines) re-entry + 5 sec (3 engine) + 5 sec (one engine) (landing)), empty first stage mass = 29t, first stage fuel = 394t.  Second stage mass = 116t + payload + fairing, fairing about 4t. (this to match Musk's statement that the first stage is pushing 125t of second stage).  Second stage ISP is 348 (SpaceX web page), empty mass about 4.5t (estimated, so 111.5t of fuel).  For Thaicom assume 3.1t, JCSAT 4.7t. 

Thaicom mission is burning the booster 3 seconds less.  That's about 9 engines * 270 kg/sec * 3 seconds = 7300 kg.  So now the fuel reserved for re-entry and landing is 25t instead of 17.5t.  At first stage burnout, the stack masses 177.1t (25 = fuel, 29 = empty mass, 116 = second stage, 3.1 = payload, 4 = fairing).  So the acceleration at burnout of the first stage is A = F/M = 825,000*9/(177.1*1000) = 42 m/s.  (the factor is 1000 is because we need the mass in kg, not tonnes). 

To find the change in performance of the first stage from the lighter payload, assume they had the same fuel reserved for landing = 17.5t.
Start mass = 394+29+116+3.1+4 = 546.1 (Thaicom), 394+29+116+4.7+4= 547.7 (JCSAT)
Burnout mass = 17.5+29+116+3.1+4 = 169.6 (Thaicom), 17.5+29+116+4.7+4 = 171.2 (JCSAT)
So dv for Thaicom = 311*9.8*l(546.1/169.6) = 3564 m/s, and 311*9.8*l(547.7/171.2) = 3544 m/s for JCSAT, or 20 m/s more for Thaicom.  We can use masses in tonnes here since the masses only appear as a ratio, which is the same in any units.

How about the second stage?  For Thaicom, initial mass = 116+3.1 = 119.1, final mass = 4.5+3.1 = 7.6.  For JCSAT, initial = 116+4.7 = 120.7, final = 4.5+4.7 = 9.2.  So dv for Thaicom is 348*9.8*l(119.1/7.6) = 9384 m/s.  For JCSAT, 348*9.8*l(120.7/9.2) = 8778.  So Thaicom has potentially 606 m/s more.

How about the re-entry burn?  We are guessing 5400 kg for the landing burn (5 sec * 3 engine, 5 sec one engine), 270 kg/sec/engine.  So the ending mass of the re-entry burn is 29+5.4 = 34.4t in both cases.  But JCSAT started with 29+17.5 = 46.5t mass, and Thaicom 29+25 = 54t mass.  So the respective delta-Vs are 311*9.8*l(46.5/34.4) = 919 m/s, and 311*9.8*l(54/34.4) = 1374 m/s.  So Thaicom will have about 450 m/s more braking before re-entry.

There are lots of assumptions and inaccuracies in these simple calculations.  However, typically the difference between two results is much less sensitive than the total values.  That's why I almost always quote the differences.


Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/26/2016 03:28 pm
Outstanding!  I can't just "like" it!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Comga on 05/26/2016 03:33 pm
So, could this be the first (obvious?) reuse in a progression of components to piecewise confirm as much reflight possiblity as possible before using a complete core?  What other components are swappable?
{snip}

Way back when SpaceX was putting parachutes in the first stages of Falcon 1, Musk said that it would be worth the effort even if they just recovered the thrust structure. 
(The equivalent for the current Falcon 9 may be the "octoweb".)

edit:  But this is not specific to the Thiacom-8 launch so we are wandering OT.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: The Amazing Catstronaut on 05/26/2016 03:35 pm
I love how this thread has devolved/evolved into arguing about white stripes. Since when has anything on this forum been this mainstream before?

https://www.youtube.com/watch?v=0J2QdDbelmY (https://www.youtube.com/watch?v=0J2QdDbelmY)

Professional feedback would certainly be welcome as to what these are. Perhaps a SpaceX or KSC insider has sharable knowledge?

I know a thing or two about photography and I'm inclined to believe they're not simply reflections, although I'll happily eat my words if it turns out that it is the case. To me that looks like paint - although I wouldn't worry excessively about it changing the thermodynamics of the engine in any meaningful manner since it'd need to be darn' tough paint to stay bonded to the engine bell through considerable heat and air blasting. I wouldn't be surprised if it came off within the first few seconds of launch.

Providing the stage survives, we should have our answer before the day is out. It'll be one of the first details to spot for in the post recovery and launch photographs.

Edit: Brilliant and comprehensive calculations Lou. I wish I could offer more than a like.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mader Levap on 05/26/2016 04:20 pm
isn't that very risky to have a re-used engine on a commercial GEO mission? or they have 1 engine redundance?
Why you assume it is used engine at all? Just because it was painted? ::)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/26/2016 04:21 pm
Why you assume it is used engine at all? Just because it was painted? ::)
Why do you assume it was painted?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Wolfram66 on 05/26/2016 04:27 pm
Those stripes on the engine don't look like paint to me. I think it's reflections that make it look like paint stripes.

They may have taken a wet sponge and simply wiped the soot off to visually mark the previously flown and dirty engine bell.


We shall now refer to said striped engine as the BeetleJuice 3 Engine ... #Snarkasm ;D ::)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/26/2016 04:32 pm
So no answer yet to the mystery of the White Stripes. While it's pure speculation, I think LouScheffer's thermal telltale idea is our best guess so far. It has to be something they can't test at McGregor (hypersonic reentry, for instance). We'll see.

I don't think there'll be a post-launch press conference, though? This is not a CRS launch for NASA.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Craig_VG on 05/26/2016 04:38 pm
The answer is here:
http://forum.nasaspaceflight.com/index.php?topic=40256.msg1540087#msg1540087
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Kabloona on 05/26/2016 04:42 pm
Some sharp-eyed reddit user noticed similar stripes on the returned JCSAT-14 stage. On the second engine from right, the stripes are red, probably as a result of the white stuff having been burned off.

http://www.universetoday.com/wp-content/uploads/2016/05/JCSAT14-4.jpg
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/26/2016 05:14 pm
Some sharp-eyed reddit user noticed similar stripes on the returned JCSAT-14 stage. On the second engine from right, the stripes are red, probably as a result of the white stuff having been burned off.

Ah, so they've done it before. We don't usually get a closeup view of all the engines before launch, so it's understandable that nobody had noticed yet.

For the record, I see no such pattern on the engines of the ORBCOMM-2 (https://i.imgur.com/wyHQRkb.jpg) (here's another angle (http://i.imgur.com/Gp0sw7R.jpg)) returned first stage.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/26/2016 06:16 pm
SpaceX ‏@SpaceX 
Weather 90% go for 5:40pm ET launch today. Droneship landing challenging -- very hot and fast first-stage reentry
Given the presumably improved margins over JCSAT-14, this feels like they are sandbagging.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mme on 05/26/2016 06:24 pm
SpaceX ‏@SpaceX 
Weather 90% go for 5:40pm ET launch today. Droneship landing challenging -- very hot and fast first-stage reentry
Given the presumably improved margins over JCSAT-14, this feels like they are sandbagging.
I think they were surprised when the booster nailed the landing on the JCSAT-14 mission.  Elon has stated in the past that they expect to lose something like 30% of the ASDS attempts for the near future.  So while it's probably an "easier" landing then JCSAT-14, I don't think it's a sure thing by any stretch of the imagination.

In other words, I'll be holding my breath during the landing burn. :)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/26/2016 06:34 pm
I think they were surprised when the booster nailed the landing on the JCSAT-14 mission.  Elon has stated in the past that they expect to lose something like 30% of the ASDS attempts for the near future.  So while it's probably an "easier" landing then JCSAT-14, I don't think it's a sure thing by any stretch of the imagination.

In other words, I'll be holding my breath during the landing burn. :)
I agree, they seemed absolutely shocked. I guess I have to remember that public messages are for the benefit of the general public, not rocket nerds like us, so "challenging; hot and fast re-entry" is still more in contrast to something like CRS-8.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: wannamoonbase on 05/26/2016 06:44 pm
SpaceX ‏@SpaceX 
Weather 90% go for 5:40pm ET launch today. Droneship landing challenging -- very hot and fast first-stage reentry
Given the presumably improved margins over JCSAT-14, this feels like they are sandbagging.
I think they were surprised when the booster nailed the landing on the JCSAT-14 mission.  Elon has stated in the past that they expect to lose something like 30% of the ASDS attempts for the near future.  So while it's probably an "easier" landing then JCSAT-14, I don't think it's a sure thing by any stretch of the imagination.

In other words, I'll be holding my breath during the landing burn. :)

If the stage is recovered by can't fly again does it count?  At this point they are learning and collecting data. 

But after that's exhuasted then recovering something that can't be used may just be an expensive exercise.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Rebel44 on 05/26/2016 06:48 pm
SpaceX ‏@SpaceX 
Weather 90% go for 5:40pm ET launch today. Droneship landing challenging -- very hot and fast first-stage reentry
Given the presumably improved margins over JCSAT-14, this feels like they are sandbagging.
I think they were surprised when the booster nailed the landing on the JCSAT-14 mission.  Elon has stated in the past that they expect to lose something like 30% of the ASDS attempts for the near future.  So while it's probably an "easier" landing then JCSAT-14, I don't think it's a sure thing by any stretch of the imagination.

In other words, I'll be holding my breath during the landing burn. :)

If the stage is recovered by can't fly again does it count?  At this point they are learning and collecting data. 

But after that's exhuasted then recovering something that can't be used may just be an expensive exercise.

Even if whole stage cannot be reused, many of its components might be reused.

And when SpaceX upgrades F9 performance, later this year, they will have more fuel available for recovery, when launching to GTO.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: MattMason on 05/26/2016 07:01 pm
Since this is a daytime flight, let's hope for another good use of the camera drone that recorded the CRS-8 landing.

Or the Thaicom-8 anti-ASDS core sampling with extra-hot kaboomy goodness. I'm not particular.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: ericspittle on 05/26/2016 07:03 pm
Since this is a daytime flight, let's hope for another good use of the camera drone that recorded the CRS-8 landing.

Or the Thaicom-8 anti-ASDS core sampling with extra-hot kaboomy goodness. I'm not particular.
I believe that camera was hanging from a NASA asset, so we won't likely see it for a commercial launch.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: northenarc on 05/26/2016 07:07 pm
SpaceX ‏@SpaceX 
Weather 90% go for 5:40pm ET launch today. Droneship landing challenging -- very hot and fast first-stage reentry
Given the presumably improved margins over JCSAT-14, this feels like they are sandbagging.
My thought is they will use any extra margin to reduce stresses on the vehicle, they want landed stages to come back slightly less cooked than JCSAT-14's booster.   
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: envy887 on 05/26/2016 07:18 pm
If the stage is recovered by can't fly again does it count?  At this point they are learning and collecting data. 

But after that's exhuasted then recovering something that can't be used may just be an expensive exercise.
Even if whole stage cannot be reused, many of its components might be reused.

And when SpaceX upgrades F9 performance, later this year, they will have more fuel available for recovery, when launching to GTO.
This is a learning process. They don't know for certain what can survive reentry and what cannot. The whole point of recovery of GTO stages (like JCSAT-14 and this launch) is to implement changes that will allow rapid reuse of all future stages, including those sent on high-energy trajectories.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/26/2016 07:59 pm
Since this is a daytime flight, let's hope for another good use of the camera drone that recorded the CRS-8 landing.

Or the Thaicom-8 anti-ASDS core sampling with extra-hot kaboomy goodness. I'm not particular.
I believe that camera was hanging from a NASA asset, so we won't likely see it for a commercial launch.
I hope you are wrong, but I think you might be right. Hopefully SpaceX works something out.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/26/2016 07:59 pm
UNSOLICITED PLUG: pony up a few bucks/pounds/euro for a subscription. Well worth it, pays for the servers and the info nearly always makes its way into articles eventually anyway so it's not "supporting secrecy" like some morons claim.
Cannot emphasize enough how true this is. I bought a yearly, and a day later (with my jaw still kinda wide open in amazement) converted to lifetime...

I'm really tempted, but factoring in the currency exchange rate (I live in Mexico) and purchasing power parity, what's US$90 a year for you guys is more like US$200 a year to me. Economics is a bitch. Is there a third-world member discount option? :P
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/26/2016 08:00 pm
For anyone who might be viewing on mobile, here's a zoomed version of the stripes on the JCSAT14 booster.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mme on 05/26/2016 08:04 pm
SpaceX ‏@SpaceX 
Weather 90% go for 5:40pm ET launch today. Droneship landing challenging -- very hot and fast first-stage reentry
Given the presumably improved margins over JCSAT-14, this feels like they are sandbagging.
I think they were surprised when the booster nailed the landing on the JCSAT-14 mission.  Elon has stated in the past that they expect to lose something like 30% of the ASDS attempts for the near future.  So while it's probably an "easier" landing then JCSAT-14, I don't think it's a sure thing by any stretch of the imagination.

In other words, I'll be holding my breath during the landing burn. :)

If the stage is recovered by can't fly again does it count?  At this point they are learning and collecting data. 

But after that's exhuasted then recovering something that can't be used may just be an expensive exercise.
Only SpaceX knows if it's worth it.  I imagine they are doing it because they get someone useful from the exercise.  In decreasing "value" of possible benefits: A reusable rocket, data to improve the rocket or flight profile, information from experiments with new tweaks, reusable components, etc ...

TL;DR - If SpaceX tries to recover a booster, they think it's worth it.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: macpacheco on 05/26/2016 08:11 pm
Looks like there is a used engine with a white stripe tracking pattern painted on (spotted by Reddit user JM93)
Possible reused engine from OG2 or CRS-8 core?
SpaceX isn't going to reuse a single engine.
That's NOT how it works.
Rockets are engineered. Tested before flight.
You don't introduce a higher risk item and see if that works.
Its not enough to see if it works.
It has to work with sufficient margins.
Just because a Falcon 9 rocket can loose an engine, doesn't make it OK to loose an engine and the other 8 make up for the lost thrust.

For instance if SpaceX has engine losses it will impact SpaceX reputation in front of DoD and NASA for crew and other high value payload launches.

SpaceX will do ALL of their homework. When they fly reused engines, it will be the whole reused first stage, with whatever refurb needed. SpaceX isn't going to launch unless they expect a fully successful launch, all 9 engines perform perfectly throughout the whole flight.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Silmfeanor on 05/26/2016 08:41 pm
SpaceX isn't going to reuse a single engine.
That's NOT how it works.
Rockets are engineered. Tested before flight.
You don't introduce a higher risk item and see if that works.
Its not enough to see if it works.
It has to work with sufficient margins.
Just because a Falcon 9 rocket can loose an engine, doesn't make it OK to loose an engine and the other 8 make up for the lost thrust.

For instance if SpaceX has engine losses it will impact SpaceX reputation in front of DoD and NASA for crew and other high value payload launches.

SpaceX will do ALL of their homework. When they fly reused engines, it will be the whole reused first stage, with whatever refurb needed. SpaceX isn't going to launch unless they expect a fully successful launch, all 9 engines perform perfectly throughout the whole flight.

Thats your opinion, not a fact.

And it is simply not true that SpaceX could not reuse an engine and expect it to be fully succesful. After all, thats the whole point of requalification. You test your used engine to make sure it is as good as the new ones. Thus, you do not expect to lose an engine, and there is no higher risk, if your qualification is stringent enough.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Rocket Science on 05/26/2016 08:46 pm
Does this Falcon have more grid fins? I was just looking at Tony's video in the update section...
1:12
http://forum.nasaspaceflight.com/index.php?topic=40182.40

Could be the angle in the video perhaps?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: tobi453 on 05/26/2016 08:46 pm
I don't know whether this engine has flown before, but SpaceX does test new parts on its engines in real flight (after qualification obviously).

"On January 6, 2014, SpaceX launched its Falcon 9 rocket with a 3D-printed Main Oxidizer Valve (MOV) body in one of the nine Merlin 1D engines. The mission marked the first time SpaceX had ever flown a 3D-printed part, with the valve operating successfully with high pressure liquid oxygen, under cryogenic temperatures and high vibration."

And it was only one engine out of nine. So I wouldn't completely rule it out that this engine has indeed flown before.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: WmThomas on 05/26/2016 08:48 pm
The evidence does not show that an engine is being reused.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: macpacheco on 05/26/2016 09:03 pm
SpaceX isn't going to reuse a single engine.
That's NOT how it works.
Rockets are engineered. Tested before flight.
You don't introduce a higher risk item and see if that works.
Its not enough to see if it works.
It has to work with sufficient margins.
Just because a Falcon 9 rocket can loose an engine, doesn't make it OK to loose an engine and the other 8 make up for the lost thrust.

For instance if SpaceX has engine losses it will impact SpaceX reputation in front of DoD and NASA for crew and other high value payload launches.

SpaceX will do ALL of their homework. When they fly reused engines, it will be the whole reused first stage, with whatever refurb needed. SpaceX isn't going to launch unless they expect a fully successful launch, all 9 engines perform perfectly throughout the whole flight.

Thats your opinion, not a fact.

And it is simply not true that SpaceX could not reuse an engine and expect it to be fully succesful. After all, thats the whole point of requalification. You test your used engine to make sure it is as good as the new ones. Thus, you do not expect to lose an engine, and there is no higher risk, if your qualification is stringent enough.

There are plenty of issues your ignoring.
First, SpaceX has already stated that at least initially reused rockets will be used with the customer's concurrence. So requal isn't nearly enough to just do it.
Second, SpaceX told us the will do 10 static fires before launching a booster, so that's the path. There's zero talk of reusing a single engine. Again its some people's desires that is so strong we just want it to be true.
Finally there's effort vs benefit. Either SpaceX is confident enough they will relaunch the entire booster after whatever refurb it need or not at all.
SpaceX announces what they're doing. They don't do it stealth mode. That's not their modus operandi.
When you factor all information available I arrive that the conclusion I stated.
Sure its my opinion. But its a well informed one.
I also want to see SpaceX reflying boosters ASAP, but I don't let that wish to cloud my judgement.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: macpacheco on 05/26/2016 09:05 pm
I the webcast countdown to start of the launch window or beginning of webcast ? 34 minutes to go right now.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rocx on 05/26/2016 09:12 pm
I the webcast countdown to start of the launch window or beginning of webcast ? 34 minutes to go right now.

To launch window. The show starts about 20-15 minutes before that time.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: vanoord on 05/26/2016 09:20 pm
@SpaceX:

Quote
Launch team finalizing review of vehicle data and check outs. Will move T-0 into the 2 hour window
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rocx on 05/26/2016 09:22 pm
That sounds like a slight delay to me.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: SkipMorrow on 05/26/2016 09:23 pm
I the webcast countdown to start of the launch window or beginning of webcast ? 34 minutes to go right now.

To launch window. The show starts about 20-15 minutes before that time.
I thought the launch was scheduled for 5:40. And I thought there was no window, so it had to launch at 5:40 or no launch today. Or am I wrong (extremely likely, given my track record)?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: vanoord on 05/26/2016 09:24 pm
Some mutterings about a wayward boat. Might explain why (if) prop loading delayed.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: toruonu on 05/26/2016 09:25 pm
I thought the launch was scheduled for 5:40. And I thought there was no window, so it had to launch at 5:40 or no launch today. Or am I wrong (extremely likely, given my track record)?

It's a 2h window.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meat10af on 05/26/2016 09:34 pm
Seeing a craft directly off the Cape right now: http://www.marinetraffic.com/en/ais/home/centerx:-80.6/centery:28.5/zoom:10
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: chalz on 05/26/2016 09:35 pm
I the webcast countdown to start of the launch window or beginning of webcast ? 34 minutes to go right now.

To launch window. The show starts about 20-15 minutes before that time.
Although with J-CSAT 14 (and all previous) they started webcast 30 mins before launch so this flight was already planned to be different. Coupled with the late static fire it seems they are trying a condensed schedule for this mission.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: JAFO on 05/26/2016 09:35 pm
Anyone else having trouble with the live stream? I'm behind a VPN in China so that might have something to do with it.


TIA
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rocx on 05/26/2016 09:37 pm
I thought the launch was scheduled for 5:40. And I thought there was no window, so it had to launch at 5:40 or no launch today. Or am I wrong (extremely likely, given my track record)?

Geotransfer orbit launches, like this one, usually have a launch window of a few hours. Launch windows to the ISS are instantaneous (with the notable exception of Atlas V who preplanned inclination corrections).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mongo62 on 05/26/2016 09:37 pm
Anyone else having trouble with the live stream? I'm behind a VPN in China so that might have something to do with it.

No, your screenshot shows what I am seeing as well. It looks like a boat is downrange, delaying the launch until it clears.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: AC in NC on 05/26/2016 09:39 pm
Seeing a craft directly off the Cape right now: http://www.marinetraffic.com/en/ais/home/centerx:-80.6/centery:28.5/zoom:10

Need torpedos. 
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/26/2016 09:39 pm
There is a picture of venting on the Update thread.  So does that mean that they have in fact loaded prop (or are loading it)?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: vanoord on 05/26/2016 09:40 pm
Speculation that SpaceX are now targeting 7.40pm Eastern / 11:40pm UTC, i.e. the end of the launch window.

Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: vanoord on 05/26/2016 09:43 pm
There is a picture of venting on the Update thread.  So does that mean that they have in fact loaded prop (or are loading it)?

Are the tanks chilled before prop loading?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/26/2016 09:44 pm
Selfish of me, but I'm glad it is being delayed because I got stuck in traffic and this way I might actually have a chance to watch. As long as it actually launches today, of course.

Don't they have the Coast Guard or somebody clearing the exclusion zone? I would think there is an actual legal responsibility associated with staying out of rocket launch ranges.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: kevin-rf on 05/26/2016 09:44 pm
Speculation that SpaceX are now targeting 7.40pm Eastern / 11:40pm UTC, i.e. the end of the launch window.
Targeting the boat? Time to hit it then and head to the bar...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mongo62 on 05/26/2016 09:45 pm
Anyone else having trouble with the live stream? I'm behind a VPN in China so that might have something to do with it.


TIA

youtube is banned in the people's republic of china, sorry

That's not it, though -- I am seeing the same thing in Canada. The problem is that the launch has been delayed, likely due to some boater deciding to enter the exclusion zone.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mlindner on 05/26/2016 09:46 pm
SpaceX isn't going to reuse a single engine.
That's NOT how it works.
Rockets are engineered. Tested before flight.
You don't introduce a higher risk item and see if that works.
Its not enough to see if it works.
It has to work with sufficient margins.
Just because a Falcon 9 rocket can loose an engine, doesn't make it OK to loose an engine and the other 8 make up for the lost thrust.

For instance if SpaceX has engine losses it will impact SpaceX reputation in front of DoD and NASA for crew and other high value payload launches.

SpaceX will do ALL of their homework. When they fly reused engines, it will be the whole reused first stage, with whatever refurb needed. SpaceX isn't going to launch unless they expect a fully successful launch, all 9 engines perform perfectly throughout the whole flight.

Thats your opinion, not a fact.

And it is simply not true that SpaceX could not reuse an engine and expect it to be fully succesful. After all, thats the whole point of requalification. You test your used engine to make sure it is as good as the new ones. Thus, you do not expect to lose an engine, and there is no higher risk, if your qualification is stringent enough.

But he's correct.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: SkipMorrow on 05/26/2016 09:47 pm
What are the links to the video feeds? Especially the "technical feed" which only has 37 viewers :)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: drsnooker on 05/26/2016 09:48 pm
Periscope link is up:
https://www.periscope.tv/murphypak/1MnxnjLAkwexO
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: toruonu on 05/26/2016 09:49 pm
What are the links to the video feeds? Especially the "technical feed" which only has 37 viewers :)

Just go to YouTube and SpaceX channel, it has both hosted and technical webcasts there. The technical one is dropping, at 29 viewers already. Hosted at 667.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/26/2016 09:50 pm
I'm viewing both feeds (hosted and technical) :D
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: dnavas on 05/26/2016 09:50 pm
What are the links to the video feeds? Especially the "technical feed" which only has 37 viewers :)

https://www.youtube.com/watch?v=wPYOtCFSLKw

there's a small link under spacex.com/webcast

There are 189 people presently watching a black screen.  :>
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: JamesH65 on 05/26/2016 09:51 pm
SpaceX isn't going to reuse a single engine.
That's NOT how it works.
Rockets are engineered. Tested before flight.
You don't introduce a higher risk item and see if that works.
Its not enough to see if it works.
It has to work with sufficient margins.
Just because a Falcon 9 rocket can loose an engine, doesn't make it OK to loose an engine and the other 8 make up for the lost thrust.

For instance if SpaceX has engine losses it will impact SpaceX reputation in front of DoD and NASA for crew and other high value payload launches.

SpaceX will do ALL of their homework. When they fly reused engines, it will be the whole reused first stage, with whatever refurb needed. SpaceX isn't going to launch unless they expect a fully successful launch, all 9 engines perform perfectly throughout the whole flight.

Thats your opinion, not a fact.

And it is simply not true that SpaceX could not reuse an engine and expect it to be fully succesful. After all, thats the whole point of requalification. You test your used engine to make sure it is as good as the new ones. Thus, you do not expect to lose an engine, and there is no higher risk, if your qualification is stringent enough.

But he's correct.

Is he? Why? Insider knowledge?

What's the point of stating a fact without some sort of indication why its is actually a fact and not conjecture? Is he saying, which he appears to be, the SpaceX will never take a used engine and put it on a new stage? Or by implication, that once an engine is on a stage, it will never be used on a different stage? ie Unless it fails, it stays on that stage forever. That seems a very ambitious statement to me.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mn on 05/26/2016 09:52 pm
Speculation that SpaceX are now targeting 7.40pm Eastern / 11:40pm UTC, i.e. the end of the launch window.

I interpret that as "we have an issue, maybe we'll get it resolved by 7:40pm so lets not say 'scrub' yet". (i.e. hoping rather than 'targeting')

And about that boat: if they were holding for a boat SpaceX would have said that, they clearly said they are holding to review data.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: SkipMorrow on 05/26/2016 09:54 pm
I must be doing it wrong. When I go to the technical webcast, I just get a black screen. Where are the pictures in the update thread coming from?
https://www.youtube.com/watch?v=wPYOtCFSLKw
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Kryten on 05/26/2016 09:56 pm
I must be doing it wrong. When I go to the technical webcast, I just get a black screen. Where are the pictures in the update thread coming from?
Those images are from people who are physically at the cape, none of the streams are live yet.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Bubbinski on 05/26/2016 09:59 pm
Is the boat away from the area now?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: buraianto on 05/26/2016 10:00 pm
The way this lady on Periscope is talking she makes it sound like a propellant load problem. Is there any word elsewhere on that?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: JasonAW3 on 05/26/2016 10:01 pm
I'm still getting no feed!  Arrgh!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/26/2016 10:01 pm
There is no boat, they would've called it clearly. It's a so-far-undisclosed technical issue, it seems.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: russianhalo117 on 05/26/2016 10:01 pm
The way this lady on Periscope is talking she makes it sound like a propellant load problem. Is there any word elsewhere on that?
yes , but cant say where
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: andrewsdanj on 05/26/2016 10:04 pm
Technical now showing 00:36 (BST) as a launch time, counting down through 92 mins now.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Bubbinski on 05/26/2016 10:04 pm
Now there's a countdown on the webcast, supposed to start in 1 hour 32 min
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: JasonAW3 on 05/26/2016 10:05 pm
I'm getting a 1hour 30 minute countdown?  I thought the Launch was to happen shortly.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: tadaniels on 05/26/2016 10:05 pm
SFN is reporting that the new target T-0 is 19:36 EDT
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: vanoord on 05/26/2016 10:07 pm
SFN is reporting that the new target T-0 is 19:36 EDT

Clock on the webcast confirms that.

Counter-argument is that's a placeholder pending resolution of whatever problem (prop loading?) caused the delay in the first place.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: russianhalo117 on 05/26/2016 10:09 pm
I'm getting a 1hour 30 minute countdown?  I thought the Launch was to happen shortly.
SFN is reporting that the new target T-0 is 19:36 EDT
SFN is reporting that the new target T-0 is 19:36 EDT
Clock on the webcast confirms that.
Counter-argument is that's a placeholder pending resolution of whatever problem (prop loading?) caused the delay in the first place.


This is a troubleshoot with the option being held to go at the end of the window. If they don't resolve the issue it'll be scrub (obviously). So end of the window is only an option right now.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris Bergin on 05/26/2016 10:09 pm
Sorry, I've only just read this thread (after someone reported it) and if someone had asked me I'd have said...so I will. The stripes are just TPS for entry heating.

I don't read every thread (no time, too busy ;D)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: manoweb on 05/26/2016 10:12 pm
The stripes are just TPS for entry heating.

TPS = ???
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris Bergin on 05/26/2016 10:13 pm
The stripes are just TPS for entry heating.

TPS = ???

Thermal Protection System. SpaceX testing things, as they do..... Obviously refining the protection of the stage as it returns.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mleigh on 05/26/2016 10:42 pm
Webcasts just jumped to 22hours 58minutes. Not official, but different information.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: ejb749 on 05/26/2016 10:47 pm
Twitter users are reporting scrub, too.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Johnnyhinbos on 05/26/2016 10:47 pm
Here's the reason from the man...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/26/2016 10:50 pm
Here's the reason from the man...
Sounds similar to an issue they had back in 2015. https://twitter.com/elonmusk/status/552437001291841539
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: JasonAW3 on 05/26/2016 10:55 pm
Sorry, I've only just read this thread (after someone reported it) and if someone had asked me I'd have said...so I will. The stripes are just TPS for entry heating.

I don't read every thread (no time, too busy ;D)

Interesting!

     If the TPS works for the engines, perhaps it could be used with the second stage.  Thermal, aerodynamic pressures, and vibration should be similar in scope and duration.  Could be it would only work on engines, but it IS something to think about.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jim on 05/26/2016 10:57 pm

     If the TPS works for the engines, perhaps it could be used with the second stage.  Thermal, aerodynamic pressures, and vibration should be similar in scope and duration.  Could be it would only work on engines, but it IS something to think about.

Different environment and application.  The issue for TPS on the second stage is mass and not if it will work.  We have no idea about the properties of this TPS to make any assertions for other uses.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/26/2016 11:04 pm
Sounds similar to an issue they had back in 2015. https://twitter.com/elonmusk/status/552437001291841539

Wow, nice memory. Indeed sounds very similar.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: starhawk92 on 05/26/2016 11:41 pm
The stripes are just TPS for entry heating.

TPS = ???

They are a specific set of reports which should be provided to upper management in a folder.  Did you get the memo?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: dorkmo on 05/27/2016 12:04 am
does the rocket world have an equivalent to AOG for aircraft?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: CyndyC on 05/27/2016 12:32 am
Here's the reason from the man...

So how does anyone examine & fix an actuator inside the 2nd stage at this point? It isn't like you can just open the hood or jack it up.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Rocket Science on 05/27/2016 12:37 am
Here's the reason from the man...

So how does anyone examine & fix an actuator inside the 2nd stage at this point? It isn't like you can just open the hood or jack it up.
They can access the interstage like "tin snips guy" a few years back...

http://forum.nasaspaceflight.com/index.php?topic=37476.620
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rsdavis9 on 05/27/2016 01:33 am
I thought the tvc was supplied pressurized kerosene from the fuel turbo pump? If so how do they test motion when the rocket isn't running?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Robotbeat on 05/27/2016 01:55 am
SpaceX isn't going to reuse a single engine.
That's NOT how it works.
Rockets are engineered. Tested before flight.
You don't introduce a higher risk item and see if that works.
Its not enough to see if it works.
It has to work with sufficient margins.
Just because a Falcon 9 rocket can loose an engine, doesn't make it OK to loose an engine and the other 8 make up for the lost thrust.

For instance if SpaceX has engine losses it will impact SpaceX reputation in front of DoD and NASA for crew and other high value payload launches.

SpaceX will do ALL of their homework. When they fly reused engines, it will be the whole reused first stage, with whatever refurb needed. SpaceX isn't going to launch unless they expect a fully successful launch, all 9 engines perform perfectly throughout the whole flight.

Thats your opinion, not a fact.

And it is simply not true that SpaceX could not reuse an engine and expect it to be fully succesful. After all, thats the whole point of requalification. You test your used engine to make sure it is as good as the new ones. Thus, you do not expect to lose an engine, and there is no higher risk, if your qualification is stringent enough.

But he's correct.
Is he? SpaceX has introduced some higher-risk items, for instance, on one of their engines (but not all), they had a 3D printed oxygen valve as a flight demo. I could definitely see them refly some of the recovered hardware like even a whole engine even if the whole stage doesn't refly.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sanman on 05/27/2016 02:16 am
So their youtube channel says tomorrow at 5:40pm - is that the new tentative launch time?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lar on 05/27/2016 02:28 am
So their youtube channel says tomorrow at 5:40pm - is that the new tentative launch time?
OrbitalATK is cited as saying 5:39pm
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lee Jay on 05/27/2016 02:39 am
So their youtube channel says tomorrow at 5:40pm - is that the new tentative launch time?
OrbitalATK is cited as saying 5:39pm

SpaceX says so too:

http://www.spacex.com/webcast

"Launch of THAICOM 8 scheduled for no earlier than Friday, May 27th at 5:39pm ET."
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jim on 05/27/2016 03:02 am
I thought the tvc was supplied pressurized kerosene from the fuel turbo pump? If so how do they test motion when the rocket isn't running?

That is first stage, I believe second stage has EMA's
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: linxiaoyi on 05/27/2016 03:04 am
I thought the tvc was supplied pressurized kerosene from the fuel turbo pump? If so how do they test motion when the rocket isn't running?

That is first stage, I believe second stage has EMA's

What is EMS?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Robotbeat on 05/27/2016 03:05 am
electromagnetic actuator, I believe.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Kim Keller on 05/27/2016 03:17 am
electromagnetic actuator, I believe.

electro-mechanical
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Fluke72 on 05/27/2016 04:34 am
I thought the tvc was supplied pressurized kerosene from the fuel turbo pump? If so how do they test motion when the rocket isn't running?

That is first stage, I believe second stage has EMA's

Second stage also has TVCs.... both are hydromechanical. GSE provides pressure during static testing.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/27/2016 05:13 am
Sounds similar to an issue they had back in 2015. https://twitter.com/elonmusk/status/552437001291841539

Wow, nice memory. Indeed sounds very similar.
Uhhh, you can credit Google for the memory.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: darkenfast on 05/27/2016 08:27 am
If this actuator is in fact a device that gimbals the engine, would I be correct in assuming that the static fire countdown included a test of it as well?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Hankelow8 on 05/27/2016 08:41 am
If this actuator is in fact a device that gimbals the engine, would I be correct in assuming that the static fire countdown included a test of it as well?

I would have expected the static fire to simulate the countdown up to engine ignition, so one should assume activation of that device should have been included in the checkout tests.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Hauerg on 05/27/2016 08:48 am
Is he? SpaceX has introduced some higher-risk items, for instance, on one of their engines (but not all), they had a 3D printed oxygen valve as a flight demo. I could definitely see them refly some of the recovered hardware like even a whole engine even if the whole stage doesn't refly.

Also: The F9 now has a BIG margin by using the fuel reserved for landing for supporting ascent in case of an engine failure.
But yeah, unless they are 99.xx% sure the used engine will work just fine they will not risk ist.

NOW would be a good time to have some kind of primitive orbital refueling infrastructure. Would be perfect for higher risk "test" flights.


Edit/Lar: Fix Quotes....  Could people PLEASE use the preview  button to make sure you haven't mangled things? If possible. Please and thank you.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: cuddihy on 05/27/2016 11:06 am
I thought the tvc was supplied pressurized kerosene from the fuel turbo pump? If so how do they test motion when the rocket isn't running?

That is first stage, I believe second stage has EMA's

Second stage also has TVCs.... both are hydromechanical. GSE provides pressure during static testing.

Folks, even hydromechanical powered actuators need electromechanical valves...there's not exactly a dude up there to turn the valves by hand 😀
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Kim Keller on 05/27/2016 04:40 pm
Folks, even hydromechanical powered actuators need electromechanical valves...there's not exactly a dude up there to turn the valves by hand 😀

Electro-mechanical actuators are referred to as such because they use electricity to drive movement. Hydraulic actuators use fluid.

An EMA is not a hydraulic actuator, and a hydraulic actuator is not an EMA.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: The_Ronin on 05/27/2016 06:59 pm
Is it even vertical on the pad?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/27/2016 07:10 pm
Hey guys, the party thread is here: http://forum.nasaspaceflight.com/index.php?topic=40089.0.  Please use it.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Bubbinski on 05/27/2016 07:28 pm
The live stream countdown is at 2 hours 11 minutes at SpaceX.com. So they haven't scrubbed as of now.

Edited to add: it appears the webcast will start at 5:38 Eastern if the countdown clock on the webcast is right. Either they're starting the webcast 1 min before launch or they'll postpone the launch to sometime later in the window
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: ericspittle on 05/27/2016 07:34 pm
The live stream countdown is at 2 hours 11 minutes at SpaceX.com. So they haven't scrubbed as of now.

Edited to add: it appears the webcast will start at 5:38 Eastern if the countdown clock on the webcast is right. Either they're starting the webcast 1 min before launch or they'll postpone the launch to sometime later in the window
It always looks like that, the actual webcast normally starts ~20 minutes earlier than the countdown says it will.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/27/2016 07:35 pm
The live stream countdown is at 2 hours 11 minutes at SpaceX.com. So they haven't scrubbed as of now.

Edited to add: it appears the webcast will start at 5:38 Eastern if the countdown clock on the webcast is right. Either they're starting the webcast 1 min before launch or they'll postpone the launch to sometime later in the window
I'm pretty sure that in the past they have sometimes started the webcast earlier than the posted time.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: just-nick on 05/27/2016 07:54 pm
The live stream countdown is at 2 hours 11 minutes at SpaceX.com. So they haven't scrubbed as of now.

Edited to add: it appears the webcast will start at 5:38 Eastern if the countdown clock on the webcast is right. Either they're starting the webcast 1 min before launch or they'll postpone the launch to sometime later in the window
It always looks like that, the actual webcast normally starts ~20 minutes earlier than the countdown says it will.
I think that they are using a T-0 clock on the webcast, not a webcast-start-time. Don't know why...just fits the data (and did yesterday, at the original T-0.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lar on 05/27/2016 08:31 pm
Hey guys, the party thread is here: http://forum.nasaspaceflight.com/index.php?topic=40089.0.  Please use it.

Some posts moved there. If you think I moved yours incorrectly....  for only 9.99 I'll move it back...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: laika_fr on 05/27/2016 08:37 pm
So i've quickly checked the weather and it's looking pretty good :

- relatively stable sunny weather over the whole state of Florida
- scattered showers in the south
- same goes with the clouds, that should not be a risk and bodes well for a clear sky above the Cape.

winds  :
- the steady surface wind may be the biggest concern, yet it remains moderate at less than 19 Miles/h (30 km/h), can't tell about the gusts. (The stage may cross 40+ Km/h winds while hovering the barge).
- no significant upper level winds or wind shear

waves : they can be seen reaching the shores, but these are small and the sea is calm at large large (max 3m) 
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: JoerTex on 05/27/2016 08:56 pm
Yes, weather looks good.  A cloud layer at 3500, but not solid.  Gust to 20 reported before 1400, but low 2 digits now.  Radar looks clear.  Forecast wind-aloft from Aviation model are never fast, calm at some levels.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: whitelancer64 on 05/27/2016 09:20 pm
WEBCAST HAS STARTED!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: buraianto on 05/27/2016 09:32 pm
What is the liquid spilling out from the connections at the base of the booster? Is that liquid oxygen?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris_Pi on 05/27/2016 09:34 pm
What is the liquid spilling out from the connections at the base of the booster? Is that liquid oxygen?

I think so. Looks like they're really hosing it down.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: fatdeeman on 05/27/2016 09:47 pm
Jaw on the floor at that onboard reentry footage
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: JebK on 05/27/2016 09:49 pm
Jaw on the floor at that onboard reentry footage

That was VERY cool.  They are starting to make this S1 landing thing look easy.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sewebster on 05/27/2016 09:49 pm
So.... doesn't it look like the entire entry burn takes place before there is any heating type stuff happening? Does this mean that the whole "plasma shield thing" or whatever isn't happening?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: yokem55 on 05/27/2016 09:50 pm
Right before the interstage camera cut out, it looked like the fins were catching on fire. But damn, they are making this look easy.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: a_godumov on 05/27/2016 09:50 pm
It was such a nice surprise when they showed the Stage 1 onboard footage. I feel like a kid in a candy store. And they made the landing look so routine! I'm crossing my fingers everything else is OK with this flight.

I have a question though - what is the object next to the landed Stage 1 on the drone ship?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris_Pi on 05/27/2016 09:52 pm
Could mean it is happening. Saw some spots on the left grid fin start glowing just a couple seconds after engine shutdown. Happened pretty quick.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/27/2016 09:52 pm
I have a question though - what is the object next to the landed Stage 1 on the drone ship?
Was confused about that myself, but I don't think it is next to it, I think it is camera foreshortening that is causing it to look like that.  Think it is close to the edge of the ship.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: HarryM on 05/27/2016 09:52 pm
You could see some heating happening around the middle part of the grid fins (where they are solid), at least that's what it looked like to me. Nice landing! I would hope that camera on S1 was running the whole time and storing it and we'll get to see the whole thing at some point. 
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: matthewkantar on 05/27/2016 09:52 pm
So.... doesn't it look like the entire entry burn takes place before there is any heating type stuff happening? Does this mean that the whole "plasma shield thing" or whatever isn't happening?

It did look like the grid fins were on fire, or getting cooked. Way to go SpaceX.

Matthew
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Devlin98 on 05/27/2016 09:52 pm
It looks like the interstage camera clouded up and then cracked.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meekGee on 05/27/2016 09:53 pm
Such lovely footage...

You can see when the grid fins are starting to bite...   And yeah, they showed the timing of the re-entry burn - I'm very surprised at that.  I thought that was secret sauce.  (Though anyone with a good telescope can figure that out, and also probably figure out the acceleration of the stage, so I guess it's not THAT much of a secret)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/27/2016 09:54 pm
It looks like the interstage camera clouded up and then cracked.

Cracked? Why do you think that?

Amazing footage S1 footage, though. A wonderful surprise!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/27/2016 09:54 pm
It looks like the interstage camera clouded up and then cracked.
They mentioned that they expected the camera to clear up again, but never cut back to it.  Hopefully we will get some post-flight video released that shows it all the way down!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: cartman on 05/27/2016 09:54 pm
screenshot of the grid fins
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: tyrred on 05/27/2016 09:54 pm
Looked to me on initial view that the fiery grid fin was the major contributor to the camera getting baked.

Probably wrong, but that was my first impression.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ben the Space Brit on 05/27/2016 09:54 pm
The commentators were saying that it might have just been something getting on the camera window and it might clear off. Certainly you could see that the grid fins were starting to cook from re-entry.

I'm thinking it was SPAM combustion products (SPAM soot, in other words) from the grid fins coating the lens.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: jimbowman on 05/27/2016 09:55 pm
So.... doesn't it look like the entire entry burn takes place before there is any heating type stuff happening? Does this mean that the whole "plasma shield thing" or whatever isn't happening?

It did look like the grid fins were on fire, or getting cooked. Way to go SpaceX.

Matthew

Could be perfectly normal given that was the first time we have seen onboard F9 reentry footage like that.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sanman on 05/27/2016 09:55 pm
Very cool - was that ablative stuff clogging the camera lens onboard stage 1? Wonder if there's a way to avoid that.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: LaunchedIn68 on 05/27/2016 09:55 pm
Anyone notice on staging what appeared to be a large amount of pitch/yaw?  I saw a thruster firing and then it was corrected on S2 ignition.  I mean I don't remember the earth moving so much after staging.  Also did anyone here the SECO call?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sewebster on 05/27/2016 09:55 pm
Could mean it is happening. Saw some spots on the left grid fin start glowing just a couple seconds after engine shutdown. Happened pretty quick.

Yeah, it is interesting. I guess it didn't "look to me" (me knowing little) how I would have expected if there was some kind of "protective sheath". I would have expected the camera to probably not have been working for one thing, and a dramatic change as soon as the engines shut down. Instead it seemed like nothing at all was happening during the burn (perfect shield effect?) and then some time after the shutdown (not too long mind you) it started getting hot...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mike_1179 on 05/27/2016 09:56 pm
So.... doesn't it look like the entire entry burn takes place before there is any heating type stuff happening? Does this mean that the whole "plasma shield thing" or whatever isn't happening?

It did look like the grid fins were on fire, or getting cooked.

Matthew

Looked like the center of the grid fin, near the actuator - I thought we were looking at hydraulic fluid burning there.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/27/2016 09:56 pm
It looks like the interstage camera clouded up and then cracked.
I saw one or two frames of what looked like a clear view before it froze. So at least it appeared to have cleared off a little bit. But yes it looked like it cracked again. Hopefully SpaceX can recover the video like they did for the CRS-8 mission and upload it to Youtube. The view we got before it froze was amazing though. Maybe they will be able to upload more than last time. A full onboard liftoff to landing video would be incredible.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/27/2016 09:56 pm
Looked to me on initial view that the fiery grid fin was the major contributor to the camera getting baked.

Probably wrong, but that was my first impression.

Baked... !?! 

EDIT: (based on many replies here) Geez, the number of people who think that they are image analysts never fails to astound.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: whitelancer64 on 05/27/2016 09:56 pm
Very cool - was that ablative stuff clogging the camera lens onboard stage 1? Wonder if there's a way to avoid that.

No, it's condensation from the atmosphere.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ohsin on 05/27/2016 09:57 pm
It looks like the interstage camera clouded up and then cracked.

Cracked? Why do you think that?

Amazing footage S1 footage, though. A wonderful surprise!

It has cracked once before.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Earendil on 05/27/2016 09:57 pm
Consider what we are witnessing here.. A year ago there were so many sceptics landing this way was even possible..  Very very soon it will look trivial..
No need to speculate on every tiny detail.. these people in SX know what they're doing..
Great times to live in!

Sent from my Lenovo B8080-H using Tapatalk

Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: macpacheco on 05/27/2016 09:57 pm
Jaw on the floor at that onboard reentry footage

That was VERY cool.  They are starting to make this S1 landing thing look easy.

Routine, sure. Boring perhaps after a few more landings.
But easy... Then do it yourself.
If it was easy, all other launch providers would be doing it !
Sorry to be an ass. The last thing we'll ever be able to say is that rocket landings are easy.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: toruonu on 05/27/2016 09:58 pm
Anyone notice on staging what appeared to be a large amount of pitch/yaw?  I saw a thruster firing and then it was corrected on S2 ignition.  I mean I don't remember the earth moving so much after staging.  Also did anyone here the SECO call?

Yeah, that got me worried too for a moment, thought there had been contact during separation and we might have LOM, but the thruster corrected the initial momentum and the engine the rest, but would be interesting to know what happened as it didn't quite look by plan...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: llanitedave on 05/27/2016 09:58 pm
Anyone notice on staging what appeared to be a large amount of pitch/yaw?  I saw a thruster firing and then it was corrected on S2 ignition.  I mean I don't remember the earth moving so much after staging.  Also did anyone here the SECO call?

Yeah, I noticed what I thought was a slow wobble right at the beginning of the stage 2 burn.  Seemed to dampen out after  a few seconds.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Joffan on 05/27/2016 09:59 pm
Anyone notice on staging what appeared to be a large amount of pitch/yaw?  I saw a thruster firing and then it was corrected on S2 ignition.  I mean I don't remember the earth moving so much after staging.  Also did anyone here the SECO call?


Yeah, it was odd -  I wondered it they (deliberately) started the S1 flip motion before stage separation, then corrected the S2 back into line when its engine started up.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/27/2016 09:59 pm
But easy... Then do it yourself.
If it was easy, all other launch providers would be doing it !
Sorry to be an ass. The last thing we'll ever be able to say is that rocket landings are easy.
"Make it look easy" usually implies the thing being done is complicated/hard, but it is pulled off so well that it "looks easy".  I think it is appropriate here...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: HarryM on 05/27/2016 09:59 pm
Anyone notice on staging what appeared to be a large amount of pitch/yaw?  I saw a thruster firing and then it was corrected on S2 ignition.  I mean I don't remember the earth moving so much after staging.  Also did anyone here the SECO call?

Seemed like that to me too.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Greg Hullender on 05/27/2016 10:00 pm
Great to see!

I'd agree that it's still "experimental" until they refly one. We still don't know that they're in good enough condition to reuse without prohibitive amounts of refurbishing.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meekGee on 05/27/2016 10:00 pm
Well if they were expecting to lose 30% of landed stages, they are quickly falling behind.  Typical.

#SpaceXNeverHitsItsNumbersOrSomething
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mtakala24 on 05/27/2016 10:00 pm
Anyone know where spaceX is going to store this stage? LC-39A is getting full...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: FishInferno on 05/27/2016 10:01 pm
Don't know if this has been asked, but a little bit before MECO the rocket seemed to be pitching up relative to prograde, did anyone else notice this or just the camera angle?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: intrepidpursuit on 05/27/2016 10:01 pm
Basically no post landing fire. There are usually a half a dozen people asking if that is normal. This time when the engines shut off so did the flame.

I wonder if the is coincidental (unlikely) or if they've changed something to prevent the fire.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: toruonu on 05/27/2016 10:01 pm
Anyone know where spaceX is going to store this stage? LC-39A is getting full...

They need to start launching them out of the way ... oh wait, they tend to come back in a few days ...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: llanitedave on 05/27/2016 10:02 pm
Anyone know where spaceX is going to store this stage? LC-39A is getting full...

I volunteer my back yard.  I have a few spare acres.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: LaunchedIn68 on 05/27/2016 10:02 pm
Anyone notice on staging what appeared to be a large amount of pitch/yaw?  I saw a thruster firing and then it was corrected on S2 ignition.  I mean I don't remember the earth moving so much after staging.  Also did anyone here the SECO call?


Yeah, it was odd -  I wondered it they (deliberately) started the S1 flip motion before stage separation, then corrected the S2 back into line when its engine started up.

Okay it wasn't just me then.  With the scrub yesterday related to S2 it made me go uh oh...then whew. ???
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: FishInferno on 05/27/2016 10:02 pm
Anyone know where spaceX is going to store this stage? LC-39A is getting full...

Judging by their previous photos, I would say they can fit 5 stages in the LC39A hangar, but that won't leave much room for anything else
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/27/2016 10:03 pm
Well if they were expecting to lose 30% of landed stages, they are quickly falling behind.  Typical.

#SpaceXNeverHitsItsNumbersOrSomething
#SpaceXSandBagging
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ben the Space Brit on 05/27/2016 10:03 pm
Anyone know where spaceX is going to store this stage? LC-39A is getting full...

I understood that the JCSAT-14 core is going to be scrapped and the ORBCOMM-G2/2 core is going to be the gate guardian at Hawthorne, so I'd expect two to be gone soon enough. From what I've seen, LC-39A can store four cores with reasonable working space between them.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: llanitedave on 05/27/2016 10:04 pm
Anyone know where spaceX is going to store this stage? LC-39A is getting full...

I understood that the JCSAT-14 core is going to be scrapped and the ORBCOMM-G2/2 core is going to be the gate guardian at Hawthorne, so I'd expect two to be gone soon enough. From what I've seen, LC-39A can store four cores with reasonable working space between them.

Scrapped?  Bite your tongue!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/27/2016 10:05 pm
Don't know if this has been asked, but a little bit before MECO the stage seemed to be pitching up relative to prograde, did anyone else notice this or just the camera angle?

It did look like it, but it may have just been an optical illusion due to the camera angle.

As for as the 2nd stage gimbaling and correcting after start, that's not unusual, although it may have been slightly more than usual. Attempting to shutting down several engines at the same time can leave some rotation in the stack that the 2nd stage has to correct after separation. It happens for Atlas V sometimes as well.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Rebel44 on 05/27/2016 10:05 pm
JAST-14 core is going west for ground testing (IIRC)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/27/2016 10:05 pm
Judging by their previous photos, I would say they can fit 5 stages in the LC39A hangar, but that won't leave much room for anything else
Probably several months before we could see FH hardware arrive on-site.  So there is probably some wiggle room here.

I remember writing a long time ago (well over a year I think) about how they might have a difficulty having to store stages between the period where they started recovering stages and when they could start reflying them.  Nobody listened :).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: LaunchedIn68 on 05/27/2016 10:05 pm
Don't know if this has been asked, but a little bit before MECO the rocket seemed to be pitching up relative to prograde, did anyone else notice this or just the camera angle?

Ya know...yeah, but I shrugged it off, thought it was me.  But that might explain the S2 pitch we saw after staging.  ???
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: macpacheco on 05/27/2016 10:05 pm
Well if they were expecting to lose 30% of landed stages, they are quickly falling behind.  Typical.

#SpaceXNeverHitsItsNumbersOrSomething
Undersell then Overdeliver. Always cause a good impression to the customers, but the critics always look for a way to call it glass half full.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: CorvusCorax on 05/27/2016 10:06 pm
So.... doesn't it look like the entire entry burn takes place before there is any heating type stuff happening? Does this mean that the whole "plasma shield thing" or whatever isn't happening?

Either that, or what we are seeing is *because* of the plasma shield. Aka, the reason the grid fins are only cooked after the engine shuts off could be because the shock cone is too wide to hit them while they are firing.

I'll have to watch the video again later to see how much delay there is between engine cutoff and grid fins on fire.





Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: vanoord on 05/27/2016 10:06 pm
Anyone know where spaceX is going to store this stage? LC-39A is getting full...

I understood that the JCSAT-14 core is going to be scrapped and the ORBCOMM-G2/2 core is going to be the gate guardian at Hawthorne, so I'd expect two to be gone soon enough. From what I've seen, LC-39A can store four cores with reasonable working space between them.

'Delta Qualification testing' which seems to equate to test it, then strip it down to component parts.

"Will they put it back together after again?" (with apologies to Red Dwarf).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: bassnfool2 on 05/27/2016 10:06 pm
It's snowing!
Is that coming from the second stage where the lox tank freezes the condensation?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/27/2016 10:06 pm
Anyone know where spaceX is going to store this stage? LC-39A is getting full...

I understood that the JCSAT-14 core is going to be scrapped and the ORBCOMM-G2/2 core is going to be the gate guardian at Hawthorne, so I'd expect two to be gone soon enough. From what I've seen, LC-39A can store four cores with reasonable working space between them.
Yeah, right now they should be ok. However, once Falcon Heavy starts being used there is going to be a LOT less room in that hangar. I am sure they will be building more storage space.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Devlin98 on 05/27/2016 10:07 pm
It looks like the interstage camera clouded up and then cracked.

Cracked? Why do you think that?

Amazing footage S1 footage, though. A wonderful surprise!

In the onboard footage near the end it looks like a line across the camera lens starting from the top just left of the center to right of the camera. Looks like a crack in glass. It starts as a small section but then the next second it goes across the entire lens.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: CorvusCorax on 05/27/2016 10:09 pm
Don't know if this has been asked, but a little bit before MECO the rocket seemed to be pitching up relative to prograde, did anyone else notice this or just the camera angle?

Ya know...yeah, but I shrugged it off, thought it was me.  But that might explain the S2 pitch we saw after staging.  ???


Yeah, I noticed that too, seems almost like they had an abnormal shutdown on stage 1 - with uneven transients giving the entire rocket a kick - both the 1st and 2nd stage kept rotating - luckily both stages managed to compensate - 2nd with engine and 1st with thrusters.

I guess that's an issue they're gonna look into, even though it didn't affect the mission.

And how awesome is this: They have the engines back on the gnd to have a look at them - if there was an issue and why.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris_Pi on 05/27/2016 10:12 pm
Wonder if that new center pusher could've been needed on this one? It seemed to be quite a bit of tilt there.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/27/2016 10:14 pm
Wonder if that new center pusher could've been needed on this one? It seemed to be quite a bit of tilt there.

All F9's now use the center pusher, this is the 4th(?) flight using that.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mvpel on 05/27/2016 10:16 pm
Yeah, I noticed that too, seems almost like they had an abnormal shutdown on stage 1 - with uneven transients giving the entire rocket a kick - both the 1st and 2nd stage kept rotating - luckily both stages managed to compensate - 2nd with engine and 1st with thrusters.

I guess that's an issue they're gonna look into, even though it didn't affect the mission.

Suppose it was a new maneuver to help reduce the impingement of the S2 plume on the top of S1 until it gets farther away, without having to change the S2 startup timing?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: CorvusCorax on 05/27/2016 10:17 pm
Don't know if this has been asked, but a little bit before MECO the rocket seemed to be pitching up relative to prograde, did anyone else notice this or just the camera angle?

Ya know...yeah, but I shrugged it off, thought it was me.  But that might explain the S2 pitch we saw after staging.  ???


Yeah, I noticed that too, seems almost like they had an abnormal shutdown on stage 1 - with uneven transients giving the entire rocket a kick - both the 1st and 2nd stage kept rotating - luckily both stages managed to compensate - 2nd with engine and 1st with thrusters.

I guess that's an issue they're gonna look into, even though it didn't affect the mission.

And how awesome is this: They have the engines back on the gnd to have a look at them - if there was an issue and why.

Just rewatched the video - it looks to me like the 2nd stage rotates the other way than the 1st stage. That would point against a thrust transient and more like an uneven push during stage separation - an asymetric push rod would have them rotate like that.

So maybe not an engine issue.  Well, never mind, they got the interstage back too, so they can also look into the separation mechanism, and find out what happened ;)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sunbingfa on 05/27/2016 10:18 pm

‏@elonmusk
Rocket landing speed was close to design max & used up contingency crush core, hence back & forth motion. Prob ok, but some risk of tipping


Meaning?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/27/2016 10:18 pm
https://twitter.com/elonmusk/status/736320322996076548

Maybe this should be the one that is used as the worst case scenario benchmark? Sounds like this one may have come in even hotter than the last one.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: CorvusCorax on 05/27/2016 10:19 pm
Yeah, I noticed that too, seems almost like they had an abnormal shutdown on stage 1 - with uneven transients giving the entire rocket a kick - both the 1st and 2nd stage kept rotating - luckily both stages managed to compensate - 2nd with engine and 1st with thrusters.

I guess that's an issue they're gonna look into, even though it didn't affect the mission.

Suppose it was a new maneuver to help reduce the impingement of the S2 plume on the top of S1 until it gets farther away, without having to change the S2 startup timing?

You're right, that could totally be it. That's ingenious!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: tyrred on 05/27/2016 10:21 pm
Looked to me on initial view that the fiery grid fin was the major contributor to the camera getting baked.

Probably wrong, but that was my first impression.

Baked... !?! 

EDIT: (based on many replies here) Geez, the number of people who think that they are image analysts never fails to astound.

Like I said before... Probably wrong.  But that was my first impression as an avid, uneducated young grasshopper rocket enthusiast.

Given the conditions at the time the camera became clouded, what do you surmise was the major contributor, heat?  Pressure?  Condensation/icing? 

I defer to the experts here   :)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris_Pi on 05/27/2016 10:22 pm
Wonder if that new center pusher could've been needed on this one? It seemed to be quite a bit of tilt there.

All F9's now use the center pusher, this is the 4th(?) flight using that.

Know it's currently in use, Meant that maybe this one might have bumped the interstage on the way out  if it hadn't had it.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rcoppola on 05/27/2016 10:24 pm
Hmm. So what exactly is a "Contingency Crush Core"? Kind of like a crumple zone in a car crash I suppose.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ben the Space Brit on 05/27/2016 10:25 pm
@elonmusk
Rocket landing speed was close to design max & used up contingency crush core, hence back & forth motion. Prob ok, but some risk of tipping


Meaning?

Meaning that the first stage has a part of its hull that is deliberately designed to crumple along its long axis to absorb landing force at extreme high-end landing velocities. However, there is no way to guarantee that this feature (something like the 'crumple zone' in modern cars) will compress symmetrically. Because of this, the stage's centre of mass is now slightly off-axis.

What's the point of recovering a stage if it's a write-off as a result? Well, a full analysis of a flown spacecraft can yield much in terms of engineering and science data. Additionally, some components (engines, octoweb, etc.) can still be salvaged and reused and the returned tanks and hull can probably be returned to the alloy manufacturers for recycling. So, even if the stage can't be reflown, SpaceX still gains.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: somepitch on 05/27/2016 10:27 pm
@elonmusk
Rocket landing speed was close to design max & used up contingency crush core, hence back & forth motion. Prob ok, but some risk of tipping


Meaning?

Meaning that the first stage has a part of its hull that is deliberately designed to crumple along its long axis to absorb landing force at extreme high-end landing velocities. However, there is no way to guarantee that this feature (something like the 'crumple zone' in modern cars) will compress symmetrically. Because of this, the stage's centre of mass is now slightly off-axis.

What's the point of recovering a stage if it's a write-off as a result? Well, a full analysis of a flown spacecraft can yield much in terms of engineering and science data. Additionally, some components (engines, octoweb, etc.) can still be salvaged and reused and the returned tanks and hull can probably be returned to the alloy manufacturers for recycling. So, even if the stage can't be reflown, SpaceX still gains.

Or maybe the crush zone is in the leg cylinders and the stage is fine.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meekGee on 05/27/2016 10:29 pm
I know he said "core", but it could be in the leg actuation mechanism too.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/27/2016 10:29 pm
Could this crush core be in the legs?  Uneven crushing could result in an asymmetrical and unbalanced aspect...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: matthewkantar on 05/27/2016 10:29 pm
Nice shout out to Douglas Adams at the end of the broadcast. Make sure you have your towel.

Enjoy, Matthew
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: punder on 05/27/2016 10:29 pm
Anyone notice on staging what appeared to be a large amount of pitch/yaw?  I saw a thruster firing and then it was corrected on S2 ignition.  I mean I don't remember the earth moving so much after staging.  Also did anyone here the SECO call?

It's okay, the earth moved for me too.   :D
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/27/2016 10:30 pm
Could this crush core be in the legs?  Uneven crushing could result in an asymmetrical and unbalanced aspect...
Some people on the SpaceX reddit are thinking the same thing.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: NovaSilisko on 05/27/2016 10:30 pm
I am assuming the crushable material is in either the pistons or the leg feet - crushable feet have been a common technique on lunar landers
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: jimbowman on 05/27/2016 10:30 pm
Some of the energy from landing would still transfer from the legs to the attachment points to that part of the core.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: x_gunsman_x on 05/27/2016 10:31 pm
I am thinking "crush core" is in legs, if you compare CRS-8 to Thiacom-8, the engine bells look higher up on CRS-8 than Thiacom-8, Thiacom-8 legs look splayed out further, which leads me to believe a mechanism in legs "crushes", giving margin on landing velocity, Thiacom-8 having a bit more than CRS-8
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: BrightLight on 05/27/2016 10:32 pm
Falcon 9 - 24 out of 25, not to bad.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/27/2016 10:32 pm
Like I said before... Probably wrong.  But that was my first impression as an avid, uneducated young grasshopper rocket enthusiast.

Given the conditions at the time the camera became clouded, what do you surmise was the major contributor, heat?  Pressure?  Condensation/icing? 

I defer to the experts here   :)
I'm no expert, but it looked mostly like condensation and heat. Someone mentioned a glass crack earlier, and it looks like the technical webcast had a longer shot that appeared to show that. Or it was some sort of dirt/debris ablated from the lower part of the stage.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: NovaSilisko on 05/27/2016 10:32 pm
And in such a case, the "core" refers to the central portion of the leg piston. I mean, I would assume they're not having the rocket core itself be crushed, that would probably void the warranty...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/27/2016 10:33 pm
Or maybe the crush zone is in the leg cylinders and the stage is fine.
Well... as long as it doesn't tip over :|.

Wonder how they handle bringing in a stage that is in a potentially unsafe condition.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/27/2016 10:33 pm
From DShadelz on the SpaceX reddit: I'm being told by an intern that "The landing legs have a crush core of aluminium honeycomb that compresses on massive impact."

https://www.reddit.com/r/spacex/comments/4l9uou/rspacex_thaicom_8_official_launch_discussion/d3mbwy6
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: NovaSilisko on 05/27/2016 10:34 pm
From DShadelz on the SpaceX reddit: I'm being told by an intern that "The landing legs have a crush core of aluminium honeycomb that compresses on massive impact."

https://www.reddit.com/r/spacex/comments/4l9uou/rspacex_thaicom_8_official_launch_discussion/d3mbwy6

Well, now we know exactly why they take the legs off.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: GusTurbo on 05/27/2016 10:35 pm
From DShadelz on the SpaceX reddit: I'm being told by an intern that "The landing legs have a crush core of aluminium honeycomb that compresses on massive impact."

https://www.reddit.com/r/spacex/comments/4l9uou/rspacex_thaicom_8_official_launch_discussion/d3mbwy6

Makes sense. I was thinking there was no way the stage itself would be crumpling if the legs were intact.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/27/2016 10:36 pm
From the update thread: (people, read the thread titles!)

elonmusk: Rocket landing speed was close to design max & used up contingency crush core, hence back & forth motion. Prob ok, but some risk of tipping.

https://twitter.com/elonmusk/status/736320322996076548

Does this explain what looks like a list to F9 on the barge ??

No, that is because of the wide angle lens.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ohsin on 05/27/2016 10:36 pm
(https://c2.staticflickr.com/8/7028/6503010689_26e5b7ab47.jpg)

https://www.flickr.com/photos/jurvetson/6503010689

Edit:

More details
https://www.flickr.com/photos/jurvetson/6503010689#comment72157628401556307
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Skylab on 05/27/2016 10:39 pm
Sorry if this is a duplicate question, but I've noticed the S1 landing very close to some white object on the deck that I can't recall from earlier attempts/landings. What is that?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jarnis on 05/27/2016 10:43 pm
Sorry if this is a duplicate question, but I've noticed the S1 landing very close to some white object on the deck that I can't recall from earlier attempts/landings. What is that?

Probably some kind of fire hose... it is right in front of the camera, not on the deck but on top of the container that also has the camera.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Zed_Noir on 05/27/2016 10:44 pm
Did SpaceX have strips of materials in the grid fins to indicate interaction with the atmosphere by flaring up?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/27/2016 10:48 pm
A few fun facts:
- F9 FT ties F91.0 for the second-most flown variant of F9; now a perfect 5 for 5
- 6th successful flight since loss of CRS-7
- 5th flight of calendar 2016
- 4th successful landing out of 6 attempts (4th out of 5 for F9 FT) since first successful landing (Orbcomm OG-2)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ohsin on 05/27/2016 10:52 pm
https://twitter.com/elonmusk/status/736328917317910528

Quote
Crush core is aluminum honeycomb for energy absorption in the telescoping actuator. Easy to replace (if Falcon makes it back to port).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Endeavour126 on 05/27/2016 10:55 pm
A few fun facts:
- F9 FT ties F91.0 for the second-most flown variant of F9; now a perfect 5 for 5
- 6th successful flight since loss of CRS-7
- 5th flight of calendar 2016
- 4th successful landing out of 6 attempts (4th out of 5 for F9 FT) since first successful landing (Orbcomm OG-2)

In addition this is the sixth launch in 158 days (new record for SpaceX). The previous was six in 169 days with the sixth not success (CRS-7).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/27/2016 10:56 pm
https://twitter.com/elonmusk/status/736328917317910528

Quote
Crush core is aluminum honeycomb for energy absorption in the telescoping actuator. Easy to replace (if Falcon makes it back to port).
How will the crew be able to work on it if there is a chance that it could fall over? This will be interesting.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 05/27/2016 10:59 pm
From the update thread: (people, read the thread titles!)

elonmusk: Rocket landing speed was close to design max & used up contingency crush core, hence back & forth motion. Prob ok, but some risk of tipping.

https://twitter.com/elonmusk/status/736320322996076548

Does this explain what looks like a list to F9 on the barge ??

No, that is because of the wide angle lens.

Disagree. Elon wouldn't make multiple references to stage possibly tipping if there wasn't a risk. And it seems pretty clear that one leg compressed more than the other three, given Elon's tweets - I don't think the possibility of asymmetrical crushing is a surprise to them. I think the risk is that the stage will tip before or during efforts to secure it in the next several hours.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: kevinof on 05/27/2016 10:59 pm
If it's stable (ie not moving) then stick some opposite list into the ASDS and bring it to vertical.

https://twitter.com/elonmusk/status/736328917317910528

Quote
Crush core is aluminum honeycomb for energy absorption in the telescoping actuator. Easy to replace (if Falcon makes it back to port).
How will the crew be able to work on it if there is a chance that it could fall over? This will be interesting.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: JebK on 05/27/2016 10:59 pm

Quote
How will the crew be able to work on it if there is a chance that it could fall over? This will be interesting.

Maybe they won't go on board OCISLY and that is why Musk is implying that it may not make it back to port.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 05/27/2016 11:00 pm
Did SpaceX have strips of materials in the grid fins to indicate interaction with the atmosphere by flaring up?

Nope. That's supersonic (perhaps still locally hypersonic) air flowing through the grids of the fins and causing localized heating of the ablative coatings applied to the fins.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/27/2016 11:04 pm
From the update thread: (people, read the thread titles!)

elonmusk: Rocket landing speed was close to design max & used up contingency crush core, hence back & forth motion. Prob ok, but some risk of tipping.

https://twitter.com/elonmusk/status/736320322996076548

Does this explain what looks like a list to F9 on the barge ??

No, that is because of the wide angle lens.

Disagree. Elon wouldn't make multiple references to stage possibly tipping if there wasn't a risk. And it seems pretty clear that one leg compressed more than the other three, given Elon's tweets - I don't think the possibility of asymmetrical crushing is a surprise to them. I think the risk is that the stage will tip before or during efforts to secure it in the next several hours.

The listing/leaning angle is different that motion. It looks like it is permanently leaning because of the wide angle lens. Don't make me look for photography 101 links. :) Any *motion* the stage might have - that is what Elon is referring to.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 05/27/2016 11:05 pm
From the update thread: (people, read the thread titles!)

elonmusk: Rocket landing speed was close to design max & used up contingency crush core, hence back & forth motion. Prob ok, but some risk of tipping.

https://twitter.com/elonmusk/status/736320322996076548

Does this explain what looks like a list to F9 on the barge ??

No, that is because of the wide angle lens.

Disagree. Elon wouldn't make multiple references to stage possibly tipping if there wasn't a risk. And it seems pretty clear that one leg compressed more than the other three, given Elon's tweets - I don't think the possibility of asymmetrical crushing is a surprise to them. I think the risk is that the stage will tip before or during efforts to secure it in the next several hours.

The listing/leaning angle is different that motion. It looks like it is permanently leaning because of the wide angle lens. Don't make me look for photography 101 links. :) Any *motion* the stage might have - that is what Elon is referring to.

Don't make me explain optics 101 and crush zone design to you. :p
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: dcporter on 05/27/2016 11:17 pm
Is the reentry video available to replay yet? I was otherwise engaged during the launch and missed out!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/27/2016 11:19 pm
Is the reentry video available to replay yet? I was otherwise engaged during the launch and missed out!

Yes, here is a snippet:
https://streamable.com/1216

EDIT: And copied from the update thread (as posted by Graham), here are the webcasts, now archived:

Technical:
https://www.youtube.com/watch?v=wPYOtCFSLKw

Hosted:
https://www.youtube.com/watch?v=zBYC4f79iXc
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: corrodedNut on 05/27/2016 11:28 pm
I'm looking at the landing replay and it looks to me that the right most (to the viewer) leg tip is several inches above the barge deck, not touching it.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rickl on 05/27/2016 11:28 pm
- 4th successful landing out of 6 attempts (4th out of 5 for F9 FT) since first successful landing (Orbcomm OG-2)

I would go so far as to say they're 5 out of 6 for successful landings (since Orbcomm).  With Jason 3, one of the legs failed to lock open and it fell over, but it looked like the landing itself was good.

If this booster tips over before it can be secured, will the landing have to be downgraded to a failure?  Unlike Jason 3, this time the landing itself damaged one of the legs.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Space Junkie on 05/27/2016 11:32 pm
So, based on Elon's tweets and the discussion above, we should not really consider this landing successful until we hear that the stage has been securely fastened to the deck.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: corrodedNut on 05/27/2016 11:33 pm
I'm looking at the landing replay and it looks to me that the right most (to the viewer) leg tip is several inches above the barge deck, not touching it.

I don't see that.

Look for the leg I described casting its shadow on the yellow circle.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/27/2016 11:35 pm
I'm looking at the landing replay and it looks to me that the right most (to the viewer) leg tip is several inches above the barge deck, not touching it.

I don't see that.

Look for the leg I described casting its shadow on the yellow circle.

I still think It looks like it is touching the ground.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: cartman on 05/27/2016 11:39 pm
I think it is mathematically impossible for it to not touch the ground, unless the rocket manages to balance itself on 2 legs on a tilting barge.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sewebster on 05/27/2016 11:46 pm
I think it is mathematically impossible for it to not touch the ground, unless the rocket manages to balance itself on 2 legs on a tilting barge.

There are four lights legs!

?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: RotoSequence on 05/27/2016 11:46 pm
I think it is mathematically impossible for it to not touch the ground, unless the rocket manages to balance itself on 2 legs on a tilting barge.

Or the legs are uneven, and the stage is behaving like a wobbly stool.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rpapo on 05/27/2016 11:47 pm
I think it is mathematically impossible for it to not touch the ground, unless the rocket manages to balance itself on 2 legs on a tilting barge.
Think about it: if one of the legs crushed a bit, it will be shorter than the rest.  If the rocket is leaning on that leg, then the opposite foot may well be off the ground a little bit.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: corrodedNut on 05/27/2016 11:47 pm
I'm looking at the landing replay and it looks to me that the right most (to the viewer) leg tip is several inches above the barge deck, not touching it.

I don't see that.

Look for the leg I described casting its shadow on the yellow circle.

I still think It looks like it is touching the ground.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: cartman on 05/27/2016 11:49 pm
Oops sorry my bad! for a while I thought it had 3! I blame it on me being a photographer using tripods all day.  ;D

I think it is mathematically impossible for it to not touch the ground, unless the rocket manages to balance itself on 2 legs on a tilting barge.

There are four lights legs!

?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: NovaSilisko on 05/27/2016 11:49 pm
It's definitely touching the ground. There's either a gap in the yellow circle's paint, or a scorch mark over it. The geometry wouldn't make sense otherwise.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/27/2016 11:55 pm
It's definitely touching the ground. There's either a gap in the yellow circle's paint, or a scorch mark over it. The geometry wouldn't make sense otherwise.

Yep, I tend to agree, but I'm not 100% sure. But we'll see for sure soon when they post higher resolution still images from the drone ship.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rickl on 05/28/2016 12:08 am
There are indeed four gaps in the yellow circle.  It looks like all the legs are on the deck to me.

https://www.flickr.com/photos/spacex/18610429514/ (https://www.flickr.com/photos/spacex/18610429514/)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: DrLucky on 05/28/2016 12:10 am
I think this is a slightly different angle clearer shot (from SpaceX Twitter).  I'll leave it to others to have opinions on leg position.

https://pbs.twimg.com/media/Cjfpe5NVAAE35KP.jpg

(https://pbs.twimg.com/media/Cjfpe5NVAAE35KP.jpg)

Tweet:

https://twitter.com/SpaceX/status/736313781907685376

Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: georgegassaway on 05/28/2016 12:12 am
It would seem the crushable core would be similar to what was used for the LEM landing gear to absorb shock:

http://heroicrelics.org/info/lm/landing-gear-strut-honeycomb.html

(https://www.hq.nasa.gov/alsj/a11/a11lm5strut.jpg)

Not exactly the same geometry, but the crushable absorber concept.

- George Gassaway
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Robotbeat on 05/28/2016 12:14 am
@elonmusk
Rocket landing speed was close to design max & used up contingency crush core, hence back & forth motion. Prob ok, but some risk of tipping


Meaning?

Meaning that the first stage ...
No.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Robotbeat on 05/28/2016 12:19 am
This thing is so tall, if they can't secure it, I wonder they will have to shove it overboard before entering the shipping lanes and the port itself.

Anyone know?
No. As long as they depressurize it, it shouldn't be a risk to other structures other than the droneship.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rickl on 05/28/2016 12:33 am
Is the 91,000 km apogee a record for SpaceX?  I don't recall hearing of one that high before.

If so, it's all the more impressive that they could do that and still land the first stage.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Robotbeat on 05/28/2016 12:34 am
Is the 91,000 km apogee a record for SpaceX?  I don't recall hearing of one that high before.

If so, it's all the more impressive that they could do that and still land the first stage.
DISCOVR higher.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: NovaSilisko on 05/28/2016 01:02 am
I think this is a slightly different angle clearer shot (from SpaceX Twitter).  I'll leave it to others to have opinions on leg position.

https://pbs.twimg.com/media/Cjfpe5NVAAE35KP.jpg

[image snipped]

Tweet:

https://twitter.com/SpaceX/status/736313781907685376

It most decidedly is touching the deck. Remember, the little footpad on the bottom of the leg extends a few centimeters below the aerodynamic housing. Any remaining percieved gap is due to that.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jdeshetler on 05/28/2016 01:12 am
The core is swinging a bit....

Can't get around latest Adobe GIF bug so here are mpg & quicktime clips speed up by 3X.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: MarsInMyLifetime on 05/28/2016 01:16 am
I can't get the gif to activate, but I believe you. In the landing vid, as the smoke is clearing away, the top of the stage is moving relative to a droplet on the camera lens. If both were in stasis, there would be no relative movement. It is rocking.

(starting from 2:23 in this vid: https://www.youtube.com/watch?v=XdtK0poWp20)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: NovaSilisko on 05/28/2016 01:45 am
Interestingly, you can see that the leg opposite to the direction of the tilt (the one accused of being aloft) doesn't seem to ever actually lift up, rather the piston extends a little to allow the foot to continue to rest on the deck.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: RocketGoBoom on 05/28/2016 02:17 am
This makes landing bingo so much easier to figure out the winner !!!

The complete landing from the perspective of the first stage, from grid deployment to the barge...

https://www.instagram.com/p/BF7wQGkF8ZJ/?taken-by=spacex
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: JebK on 05/28/2016 02:19 am
This makes landing bingo so much easier to figure out the winner !!!

https://www.instagram.com/p/BF7wQGkF8ZJ/?taken-by=spacex

WOW! Amazing video!  Here's hoping they release that at normal speed!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 02:23 am
I calculated the entry and landing burns to be about 18 seconds each. For the landing burn, the starting point was from the beginning of the callout.

For the supposed camera cracking, that looked like a bit of dirt hitting the camera lens to me.

Update. The landing video shows that the camera did not crack.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: cscott on 05/28/2016 02:31 am
I wonder if the "sped up" nature is due to itar and/or protecting their "special sauce".  They might be able to insert just enough frame rate jitter to obscure the exact duration of various key events.

Or maybe they just thought it looked cooler this way.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Elmar Moelzer on 05/28/2016 02:38 am
This makes landing bingo so much easier to figure out the winner !!!

https://www.instagram.com/p/BF7wQGkF8ZJ/?taken-by=spacex

WOW! Amazing video!  Here's hoping they release that at normal speed!
I second that hope! I don't get why they think they had to accelerate it. This is cool enough to watch in real time all the the way down!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: docmordrid on 05/28/2016 02:47 am
https://www.youtube.com/watch?v=4jEz03Z8azc
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/28/2016 02:50 am
I wonder if the "sped up" nature is due to itar and/or protecting their "special sauce".  They might be able to insert just enough frame rate jitter to obscure the exact duration of various key events.

Or maybe they just thought it looked cooler this way.
I highly doubt it. They showed it in normal speed during the webcast, and even though it cutoff while reentering I am sure that if they had a solid connection they would have showed it the whole way in. I watched the hosted webcast after watching the technical one live, and one of the guys even made it sound like they were originally planning on showing it even after reentry. Besides, there is a lot more to it than just the timing of the events.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Space Ghost 1962 on 05/28/2016 02:50 am
Note the torque on entry burn engine shutdown.

Also, looks like they aim for a near miss off the edge of the barge until braking burn engine starts. Then the redirect to the center of the barge.

You also can note that the grid fins roast after the entry burn before transonic.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Wolfram66 on 05/28/2016 02:58 am
49:56 into technical broadcast, a big chunk of something comes off the MVac right after shutdown. ice, coke or insulation? Any ideas, gang?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 05/28/2016 03:01 am
I watched the Technical webcast live and then later this evening watched the Hosted webcast through until SECO1 and parking orbit. Did anyone else notice one of the hosts, at about 38:30 in the webcast during the landing burn discussion, mention that they apparently did a 1-3-1 engine landing burn? I watched it twice and that's what it sounded to me like he was saying.

If so, I wonder if Lou can work his calculator magic and come up with some good dV estimates for the landing profile.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: AC in NC on 05/28/2016 03:02 am
Also, looks like they aim for a near miss off the edge of the barge until braking burn engine starts. Then the redirect to the center of the barge.

Somewhere there was a diagram that showed just that.  However, I thought it was dramatic how late the move to center was.  Very impressive that they don't need to have the landing point of impact centered earlier than that.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Elmar Moelzer on 05/28/2016 03:06 am
Not sure if this has been discussed before, but what about that "tarp"? covering part of the second stage engine? Is that some sort of extra insulation for the restart later, or what is the purpose of it? I don't think I have seen it before.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: arsenal on 05/28/2016 03:09 am
I watched the Technical webcast live and then later this evening watched the Hosted webcast through until SECO1 and parking orbit. Did anyone else notice one of the hosts, at about 38:30 in the webcast during the landing burn discussion, mention that they apparently did a 1-3-1 engine landing burn? I watched it twice and that's what it sounded to me like he was saying.

If so, I wonder if Lou can work his calculator magic and come up with some good dV estimates for the landing profile.
At 38:30 there were no hosts, just the graphic of the second stage in relationship to the Earth.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 05/28/2016 03:11 am
I watched the Technical webcast live and then later this evening watched the Hosted webcast through until SECO1 and parking orbit. Did anyone else notice one of the hosts, at about 38:30 in the webcast during the landing burn discussion, mention that they apparently did a 1-3-1 engine landing burn? I watched it twice and that's what it sounded to me like he was saying.

If so, I wonder if Lou can work his calculator magic and come up with some good dV estimates for the landing profile.
At 38:30 there were no hosts, just the graphic of the second stage in relationship to the Earth.

You missed the part I bolded above.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: ChrisC on 05/28/2016 03:21 am
I haven't seen it discussed yet, but there seemed be an awful lot of snow and even debris floating around in the minute or so before second stage relight.  In the technical webcast it starts at the 47m50s point (https://www.youtube.com/watch?v=wPYOtCFSLKw#t=47m50s) (ignition occurs at 48m40s).  I don't recall it being that bad before.  You can also see the ice quickly growing on the engine, but I expect to see that, part of chilldown.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/28/2016 03:21 am
The video really demonstrates how effective the grid find are!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Wolfram66 on 05/28/2016 03:37 am
Could anyone see how the BeetleJuice engine faired on the landing stage? Did the stripes remain on the bell?

 8) ::)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rabe0070 on 05/28/2016 03:37 am
I watched the Technical webcast live and then later this evening watched the Hosted webcast through until SECO1 and parking orbit. Did anyone else notice one of the hosts, at about 38:30 in the webcast during the landing burn discussion, mention that they apparently did a 1-3-1 engine landing burn? I watched it twice and that's what it sounded to me like he was saying.

If so, I wonder if Lou can work his calculator magic and come up with some good dV estimates for the landing profile.

It was very clear that he said it was a 1-3-1 and I would also appreciate the the estimates for the landing profile.

Also, I know it was sped up, but it seemed they were able to stop the spinning and orient the stage pretty quickly before the reentry burn.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meekGee on 05/28/2016 03:40 am
I'm surprised by just how quickly the jets are able to stop the end-over-end tumble.

One second it's tumbling, and then it just stops with almost no slow-down...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: chalz on 05/28/2016 03:42 am
I haven't seen it discussed yet, but there seemed be an awful lot of snow and even debris floating around in the minute or so before second stage relight.  In the technical webcast it starts at the 47m50s point (https://www.youtube.com/watch?v=wPYOtCFSLKw#t=47m50s) (ignition occurs at 48m40s).  I don't recall it being that bad before.  You can also see the ice quickly growing on the engine, but I expect to see that, part of chilldown.
I think these particles have become more apparent since they started using the digital cameras. Probably an upgrade they did with the full thrust model.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Joffan on 05/28/2016 04:37 am
I haven't seen it discussed yet, but there seemed be an awful lot of snow and even debris floating around in the minute or so before second stage relight.  In the technical webcast it starts at the 47m50s point (https://www.youtube.com/watch?v=wPYOtCFSLKw#t=47m50s) (ignition occurs at 48m40s).  I don't recall it being that bad before.  You can also see the ice quickly growing on the engine, but I expect to see that, part of chilldown.

I noticed that too - I wondered if it was the exhaust from the attitude motors settling the prop tank. After final SECO there was no such "snow".
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: MarsInMyLifetime on 05/28/2016 04:49 am
This thing is so tall, if they can't secure it, I wonder they will have to shove it overboard before entering the shipping lanes and the port itself.

Anyone know?
No. As long as they depressurize it, it shouldn't be a risk to other structures other than the droneship.

I'm not sure your thesis is correct.
IMHO, A 150 foot long, several thousand kg, depressurized tube in the water or falling on top of a cruise ship seems just as dangerous as a 150 foot long pressurized tube...
I think it's the difference between the kinetic energy of the tipping stage--like a falling tree--and the potential energy of the pressurants that initiate RUD.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: John.bender on 05/28/2016 04:56 am
I heard the 1-3-1 point he made too. Never heard that before.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: deruch on 05/28/2016 05:23 am
I heard the 1-3-1 point he made too. Never heard that before.

Makes sense.  Having big control authority through the gimballed center engine could compensate for any difference in the rate that the 2 outboard engines come up to full thrust.  For coarser maneuvers like the reentry burn (or a boostback burn, though one wasn't used on this mission) it wouldn't be that important.  But for the finer, terminal targeting of the landing burn, where the F9 is coming in hot and doesn't have much time or margin to adjust, that extra bit of control might make a difference.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 06:08 am
Screen grabs from the hosted webcast.

Our presenters. I thought the addition of "Earth" for the location of Hawthorne was amusing.

JCSat 14 entered atmosphere at 6300 km/h (1750 m/s). Five times aerodynamic heating of CRS-8. Landing burn at 850 m altitude. Touchdown at 4 km/h (1.1 m/s) 2 m from bulls eye. Three seconds of propellant remaining. The TVC actuator was off in yesterdays attempt.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 06:10 am
Talking about Thaicom 8. Mass about 3000 kg.

Payload fairing deployment from a previous mission.

Engineers are looking into ways for fairing recovery. Droneship 680 km off coast.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 06:17 am
Talking about recovered boosters. OG2 booster going to Hawthorne, JCSat 14 booster called "life leader" and CRS-8 booster to refly later this year. Reuse to lower cost by up to 30%.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 06:20 am
Interesting view of the JCSat 14 landing.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 06:21 am
JCSat 14 recovery.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 06:23 am
Thaicom 8 launch. Just to make sure you know, Cape Canaveral is located on Earth. :-)

Welcome to our new overlords!

First Stage cutoff.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 06:26 am
Interstage just before stage separation.

Second stage ignition.

Mvac ring separation. First stage is to left of engine nozzle.

First stage dropping away.

Inside the fairing.

Fairing separation.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 06:42 am
Launch speed up to 8000 km/h (2220 m/s). Slow down from 5800 km/h (1610 m/s). Parking orbit is 160x485 km.

First stage descent. Cold gas thruster working.

Entry burn starts at T+6:34.

Entry burn ends at T+6:52 for an 18 second burn.

Small flames near the fin attachment points.

Engine flame above drone ship.

Touchdown!

Smoke clearing away.

Second stage cutoff at T+8:59 minutes, 26,930 km/h (7480.6 m/s relative to rotating Earth) and 164 km. I really wish SpaceX would give inertial speed. I estimate the inertial speed to be 7889.5 m/s.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 06:49 am
Mvac thrust can vary from 80 to 210 klbf (356-934 kN). Throttling started soon after second stage second ignition.

Second stage cutoff at 36440 km/h (10,122.2 m/s relative, 10,531.2 m/s inertial).

Simple launch animation. I've enhanced these to make them a bit clearer.

Fairing separation incorrectly shown after second stage first cutoff.

Geosynchronous altitude correctly show as about 36,000 km.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/28/2016 06:52 am
Spacecraft separation.

A happy set of presenters.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Elmar Moelzer on 05/28/2016 07:01 am
So what is that black tarp over the second stage engine all about? Is this new? I cant remember seeing it before.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jarnis on 05/28/2016 07:27 am
So what is that black tarp over the second stage engine all about? Is this new? I cant remember seeing it before.

Been there at least since F9 FT started to fly.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Elmar Moelzer on 05/28/2016 07:47 am
So what is that black tarp over the second stage engine all about? Is this new? I cant remember seeing it before.

Been there at least since F9 FT started to fly.
Ha! Somehow I never noticed it! What is it for?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: NovaSilisko on 05/28/2016 09:15 am
So what is that black tarp over the second stage engine all about? Is this new? I cant remember seeing it before.

Been there at least since F9 FT started to fly.
Ha! Somehow I never noticed it! What is it for?

Thermal control seems most likely. They don't want to risk a restart failure from frozen lines ever again.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Paul_G on 05/28/2016 10:35 am
Note the torque on entry burn engine shutdown.

Also, looks like they aim for a near miss off the edge of the barge until braking burn engine starts. Then the redirect to the center of the barge.

You also can note that the grid fins roast after the entry burn before transonic.

I wonder if this gives us a clue as to why the impact point for the SES 9 recovery attempt was where it was - watching this landing, you can see how a landing burn that didn't quite work our for what ever reason would end up with a fast moving stage coming in to the corner of the droneship.

Paul
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: corrodedNut on 05/28/2016 12:54 pm
Note the torque on entry burn engine shutdown.

Also, looks like they aim for a near miss off the edge of the barge until braking burn engine starts. Then the redirect to the center of the barge.

You also can note that the grid fins roast after the entry burn before transonic.

I wonder if this gives us a clue as to why the impact point for the SES 9 recovery attempt was where it was - watching this landing, you can see how a landing burn that didn't quite work our for what ever reason would end up with a fast moving stage coming in to the corner of the droneship.

Paul

Just because the stage is *pointing* a certain direction doesn't necessarily mean that it is *aiming* for the same location.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: gregpet on 05/28/2016 01:13 pm
I wonder if you will start seeing experiments with the re-entry burn.  Different profiles of burn times, engine firings (maybe just 2 outboard instead of all three), etc to help reduce propellant usage so that they can increase margin on the landing burn.  It seems like the landing burn will need to be increased to slow S1 for these higher velocity launches (or much stronger landing legs that will add weight).

All that said, you have to survive the re-entry to get the opportunity to try a landing so maybe not a lot of margin there either!

Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: StevenV on 05/28/2016 02:15 pm
Did anyone notice from the video, or know of, any new fairing recovery experiments with this launch?

It was mentioned in the webcast that they're working on fairing recovery, but nothing specific.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: testguy on 05/28/2016 02:37 pm
Anyone notice a second cheer from employees within a minute after the employees cheered for the landing?  May have been for a fairing video they could see but we didn't.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: cscott on 05/28/2016 02:42 pm
No, the cheer was for second stage MECO1 SECO1, which happens very shortly after first stage landing.

Edit: SECO not MECO, thanks @baldusi.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: ugordan on 05/28/2016 03:08 pm
Note the torque on entry burn engine shutdown.

What looks to me like is happening is the reentry burn is done with a certain angle of attack (going back to CRS-4 IR footage, there were hints of this in the plume asymmetry), you can tell the exhaust appears the be swept by predominantly to the left. Near the end of the burn, aero-torque becomes significant, but the engines burning and having control authority still maintain that AoA. Once shutdown, the stage immediately relaxes to zero AoA position (or at least to the limits of the grid fin authority) due to airflow.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: ugordan on 05/28/2016 03:12 pm
No, the cheer was for second stage MECO1 SECO1, which happens very shortly after first stage landing.

Edit: SECO not MECO, thanks @baldusi.

SECO happened more than a minute prior to the 2nd cheer. I'm pretty sure they were cheering because they got the ASDS video back after the dropout and the stage was still standing. Rewatch the hosted stream and look at the mission control background.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: llanitedave on 05/28/2016 03:25 pm
Not sure if this has been discussed before, but what about that "tarp"? covering part of the second stage engine? Is that some sort of extra insulation for the restart later, or what is the purpose of it? I don't think I have seen it before.

It was there and I made a post mentioning it during the previous mission.  I don't know when they started using it.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: RedSky on 05/28/2016 03:56 pm
This take on the on-board video is pretty interesting.  While it has been slowed down a bit (.25)... what makes this great is he tracks the location of OCISLY most of the way down.  I tried doing this by keeping track of cloud patterns, and it seems he's gone and done it really well.

www.youtube.com/watch?v=b-yWTH7SJDA
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: llanitedave on 05/28/2016 04:01 pm
This take on the on-board video is pretty interesting.  While it has been slowed down a bit (.25)... what makes this great is he tracks the location of OCISLY most of the way down.  I tried doing this by keeping track of cloud patterns, and it seems he's gone and done it really well.

www.youtube.com/watch?v=b-yWTH7SJDA (http://www.youtube.com/watch?v=b-yWTH7SJDA)

This is a good perspective to look for wobble from the asymmetrical crushing of the leg's shock absorbers.  I don't see any.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sewebster on 05/28/2016 04:02 pm
The TVC actuator was off in yesterdays attempt.

What does this mean?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Davp99 on 05/28/2016 04:12 pm
For a minute I thought John Federspiel was Clark Kent.. 8)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Wolfram66 on 05/28/2016 04:57 pm
Around :19 sec of sped up video, you can see the transonic shockwave briefly as stage drops below supersonic velocity
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sanman on 05/28/2016 05:04 pm
Somehow I feel that SpaceX's decision to give us the onboard rocketcam descent video was influenced by Blue Origin's previous release of their onboard rocketcam descent video.

Hey SpaceX - can you give us some sound next time, too? :)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: starhawk92 on 05/28/2016 05:09 pm
For those who have been comparing this (Thaicom) S1 reentry profile to the prior (JSCAT) S1 reentry profile (with ASDS being placed differently) -- do we expect a core with less damage this time?  Or is trajectory not the influencing factor?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: abaddon on 05/28/2016 05:54 pm
I expect less damage, mostly due to  no post-landing engine bay fire, and maybe a little bit due to a likely less extreme reentry.  Just my gut feeling though.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Robotbeat on 05/28/2016 06:07 pm
I expect less damage, mostly due to  no post-landing engine bay fire, and maybe a little bit due to a likely less extreme reentry.  Just my gut feeling though.
I think they may have done some quick things like bolted down TPS better or added a little bit of SPAM or some other protective material.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: terryy on 05/28/2016 07:04 pm
I was curious to figure out how fast they sped up the landing video, so I did some quick calculations from the webcast video.

On the webcast video re-entry burn started at T+6:33 and the stage landed on OCISLY at T+8:40 for a total duration of 127 seconds.

On the sped up video the re-entry burn started at 13 seconds into the video and landing occurred 24 seconds in for a duration of 11 seconds.

So ROUGHLY it looks like they sped the video up by 12x.  Too bad YouTube doesn't have an option for us to set the playback speed that low.  :P
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mongo62 on 05/28/2016 07:27 pm
I expect less damage, mostly due to  no post-landing engine bay fire, and maybe a little bit due to a likely less extreme reentry.  Just my gut feeling though.

Is it possible that changes have already been made to the engine plumbing in response to the previous propellant fires? As far as I know, the three previous recovered cores had all experienced fires in the engine bays after landing and engine shutdown, so the lack of a fire this time indicates (to me) that a fix has been applied.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sevenperforce on 05/28/2016 07:46 pm
I expect less damage, mostly due to  no post-landing engine bay fire, and maybe a little bit due to a likely less extreme reentry.  Just my gut feeling though.

Is it possible that changes have already been made to the engine plumbing in response to the previous propellant fires? As far as I know, the three previous recovered cores had all experienced fires in the engine bays after landing and engine shutdown, so the lack of a fire this time indicates (to me) that a fix has been applied.
Probably, though I am inclined to think it more likely that a change in the engine shutdown sequence is responsible, rather than any alteration to the plumbing of the engine bay.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Bob Shaw on 05/28/2016 07:47 pm
I'm presently uploading a 25% speed version of the SpaceX video to YouTube - it'll be available, I think, in about 30 minutes. Still no SpaceX sound, but some suitably bouncy music from Kevin McLeod!

https://www.youtube.com/watch?v=aEkJffhMK5Q
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: wannamoonbase on 05/28/2016 09:00 pm
Somehow I feel that SpaceX's decision to give us the onboard rocketcam descent video was influenced by Blue Origin's previous release of their onboard rocketcam descent video.

Hey SpaceX - can you give us some sound next time, too? :)

SpaceX has nothing to prove with regards to BO.

I'm sure they've had this same feed for awhile and are sharing when they are comfortable.

What would be super sweet to see is during the telecasts if they had telemetry for the S1 from separation to landing.  Altitude and speed combined with that feed and side by side with the S2 would be some great TV.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: kevinof on 05/28/2016 09:10 pm
Can't get over how stable they have that stage - zero roll that I can see. Really good control.

I'm presently uploading a 25% speed version of the SpaceX video to YouTube - it'll be available, I think, in about 30 minutes. Still no SpaceX sound, but some suitably bouncy music from Kevin McLeod!

https://www.youtube.com/watch?v=aEkJffhMK5Q
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Bob Shaw on 05/28/2016 09:34 pm
Somehow I feel that SpaceX's decision to give us the onboard rocketcam descent video was influenced by Blue Origin's previous release of their onboard rocketcam descent video.

Hey SpaceX - can you give us some sound next time, too? :)

SpaceX has nothing to prove with regards to BO.

I'm sure they've had this same feed for awhile and are sharing when they are comfortable.

What would be super sweet to see is during the telecasts if they had telemetry for the S1 from separation to landing.  Altitude and speed combined with that feed and side by side with the S2 would be some great TV.

There's no doubt that the sound in the BO descent footage from the GH vent camera added enormously to the presentation, but they were going rather slower and lower so there was more chance of hearing something - though having some Merlins lighting up at the other end of the stage would surely at least result in considerable transmitted noise. I still love the airliner-like clunks and whirrs on the BO footage!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: nisse on 05/28/2016 09:42 pm
In the beginning of the hosted webcast the presenter made a claim that the Falcon 9 was assembled on the transporter erector launcher. Is that true? I was under the impression that the rocket got assembled on fixtures that could rotate the rocket and then lifted onto the TEL later once assembled.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meekGee on 05/28/2016 09:56 pm
I'm presently uploading a 25% speed version of the SpaceX video to YouTube - it'll be available, I think, in about 30 minutes. Still no SpaceX sound, but some suitably bouncy music from Kevin McLeod!

https://www.youtube.com/watch?v=aEkJffhMK5Q

Nice music track, nice timing...

Of course you can watch this one at 0.25x, but that's like getting postcards in the mail...  Can't wait for the HiFi version.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Bob Shaw on 05/28/2016 09:58 pm
I'm presently uploading a 25% speed version of the SpaceX video to YouTube - it'll be available, I think, in about 30 minutes. Still no SpaceX sound, but some suitably bouncy music from Kevin McLeod!

Nice music track, nice timing...

Of course you can watch this one at 0.25x, but that's like getting postcards in the mail...  Can't wait for the HiFi version.

Me too!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rpapo on 05/28/2016 10:15 pm
In the beginning of the hosted webcast the presenter made a claim that the Falcon 9 was assembled on the transporter erector launcher. Is that true? I was under the impression that the rocket got assembled on fixtures that could rotate the rocket and then lifted onto the TEL later once assembled.
You've got it right.  Do you ever see the TEL present in the hangar in those pre-launch pictures showing off the nice clean rockets being prepared for launch?  I can't recall any such picture.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sanman on 05/28/2016 10:28 pm
There's no doubt that the sound in the BO descent footage from the GH vent camera added enormously to the presentation, but they were going rather slower and lower so there was more chance of hearing something - though having some Merlins lighting up at the other end of the stage would surely at least result in considerable transmitted noise. I still love the airliner-like clunks and whirrs on the BO footage!

Indeed, the actual sounds of the spacecraft's machinery really added to the realism and vividness for me. Hearing it for the Falcon9 would be great if they could give us that. We'll have to hope they'll let us hear it sooner or later. :)

Some have already noted that sound conducts through the vehicle's structure, even in a vacuum .
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: macpacheco on 05/28/2016 10:37 pm
I was curious to figure out how fast they sped up the landing video, so I did some quick calculations from the webcast video.

On the webcast video re-entry burn started at T+6:33 and the stage landed on OCISLY at T+8:40 for a total duration of 127 seconds.

On the sped up video the re-entry burn started at 13 seconds into the video and landing occurred 24 seconds in for a duration of 11 seconds.

So ROUGHLY it looks like they sped the video up by 12x.  Too bad YouTube doesn't have an option for us to set the playback speed that low.  :P
I downloaded the youtube video in mp4 format and used linux mplayer -speed 0.01 to slowdown 100x. It certainly didn't look like a full 100x slowdown but perhaps 20x.

http://en.savefrom.net/#url=https://www.youtube.com/watch?v=4jEz03Z8azc
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: MarsInMyLifetime on 05/28/2016 11:12 pm
I noticed that the contrail shadow from launch shows on both the 2nd stage camera's view from the Technical Webcast and at the very start of the sped up view from the booster's camera. I chose the second stage frame to include the booster to show its relationship with the scenery below which should match closely to the time of the frame from the sped-up booster clip. Mainly an interesting point of relationship between the two clips and viewpoints.

Second stage view back towards booster and trail shadow, then...
Booster view in the same direction at the same time.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: LouScheffer on 05/29/2016 01:38 am
Here's my estimation of the delta-v required to establish GEO from the supersynchronous Thaicom-8 orbit. The inclination change is split optimally between the apogee and circularization burns

I find that lowest delta-v is aprox. 1487 m/s doing 94% of the inclination change during the apogee burn and the remaining 6% at circularization.

I get 1491 m/s with all the inclination change at apogee, which is entirely consistent.

Also, assuming both JCSAT and Thaicom started from 189x189x27.5 degree orbits, then going to the JCSAT orbit (189x33600, 23.70 degrees) takes about 2550 m/s.  Going to a Thaicom like orbit of 189x90000, 21.21 degrees, takes about 3040 m/s or about +490 m/s more. (These are not the exact orbits, and these are not completely impulsive burns, but the number should be close.)

That's almost exactly what we   calculated upthread  (http://forum.nasaspaceflight.com/index.php?topic=40256.msg1539728#msg1539728) for the difference in payload mass and the slightly shorter first stage burn.  (-126 m/s for the shorter first stage burn, +20 m/s for the first stage with lighter payload, and +600 for second stage performance with less mass)  In particular this is consistent with a 4.5t empty mass of the second stage.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/29/2016 04:47 am
The TVC actuator was off in yesterdays attempt.
What does this mean?

We're not exactly sure as SpaceX did not give any details. It could be a time lag between actuation and movement, an offset in the angle of movement or something else.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: sewebster on 05/29/2016 04:55 am
The TVC actuator was off in yesterdays attempt.
What does this mean?

We're not exactly sure as SpaceX did not give any details. It could be a time lag between actuation and movement, an offset in the angle of movement or something else.
Ah, right, off as in "off spec", not "turned off".
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: nisse on 05/29/2016 08:23 am
In the beginning of the hosted webcast the presenter made a claim that the Falcon 9 was assembled on the transporter erector launcher. Is that true? I was under the impression that the rocket got assembled on fixtures that could rotate the rocket and then lifted onto the TEL later once assembled.
You've got it right.  Do you ever see the TEL present in the hangar in those pre-launch pictures showing off the nice clean rockets being prepared for launch?  I can't recall any such picture.
So why would they make such a claim? SpaceX hosts don't know what they are talking about?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: darkenfast on 05/29/2016 09:04 am
I think it was just a slightly imprecise use of the language, as in: the rocket and the TEL are finally brought together (assembled) for roll-out.  When you're in front of a camera in the middle of a factory and being a presenter is not your main job, it's easy to mix-up a word or phrase.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Brick_top on 05/29/2016 10:18 am
sorry for the non-technical off-topic post... but congrats to spacex for another great launch and landing, as strange as it might be, i feel that landings are now normal.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Barrie on 05/29/2016 10:54 am
sorry for the non-technical off-topic post... but congrats to spacex for another great launch and landing, as strange as it might be, i feel that landings are now normal.

Yes, it seemed to me that they turned a corner with this one. Both landing and launch seemed relatively straightforward, in spite of the one-day slip. It's easy to think the hardware does it all, but the success is also down to the people working it.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: MechE31 on 05/29/2016 12:16 pm
In the beginning of the hosted webcast the presenter made a claim that the Falcon 9 was assembled on the transporter erector launcher. Is that true? I was under the impression that the rocket got assembled on fixtures that could rotate the rocket and then lifted onto the TEL later once assembled.
You've got it right.  Do you ever see the TEL present in the hangar in those pre-launch pictures showing off the nice clean rockets being prepared for launch?  I can't recall any such picture.
So why would they make such a claim? SpaceX hosts don't know what they are talking about?

Have you ever seen the payload attached when it wasn't on the TE?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rpapo on 05/29/2016 12:56 pm
In the beginning of the hosted webcast the presenter made a claim that the Falcon 9 was assembled on the transporter erector launcher. Is that true? I was under the impression that the rocket got assembled on fixtures that could rotate the rocket and then lifted onto the TEL later once assembled.
You've got it right.  Do you ever see the TEL present in the hangar in those pre-launch pictures showing off the nice clean rockets being prepared for launch?  I can't recall any such picture.
So why would they make such a claim? SpaceX hosts don't know what they are talking about?

Have you ever seen the payload attached when it wasn't on the TE?
Yes, when the payload was Dragon.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 05/29/2016 01:28 pm
I get 1491 m/s with all the inclination change at apogee, which is entirely consistent.

The difference between doing all the inclination change at apogee and splitting it between the burns is so small (for instance, using a slightly different value for the radius of the Earth makes a bigger difference) that you could do it all at apogee with no measurable impact on fuel reserves.

But I've seen that satellite operators sometimes (usually?) do multiple burns to get their craft to GEO (SES-8, also injected into supersynchronous transfer by SpaceX, was said to have done 5 burns (http://space.stackexchange.com/questions/2914/how-long-does-it-take-for-a-satellite-to-reach-geo), and the Indians used 3 apogee burns (http://www.planetary.org/blogs/jason-davis/20140116-how-to-get-a-satellite-to-gto.html?referrer=https://www.google.com.mx/) for GSAT-14 after they launched it to standard GTO).

Does anyone have info on Thaicom-8's exact trajectory plan?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mvpel on 05/29/2016 03:17 pm
You've got it right.  Do you ever see the TEL present in the hangar in those pre-launch pictures showing off the nice clean rockets being prepared for launch?  I can't recall any such picture.

(http://spaceflightnow.com/wp-content/uploads/2014/12/CRS-3-DRAGON-FALCON-9-MATE.jpeg)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ronsmytheiii on 05/29/2016 05:41 pm

They already  have Building AO to process stages before going to the SLC-40 HIF.  Going to 39 isn't going to provide any more advantages.

I thought that the first stage outgrew AO when they switched to v1.1. If not then SpaceX might need to use it with the newest returned core.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mlindner on 05/29/2016 08:35 pm
There has been some discussion that the rocket is not aimed retrograde during it's descent. I want to dispel that idea and note that when the stage re-orients during its descent for the re-entry burn, this is done to avoid drifting of the IIP (Instantaneous Impact Point) of the stage. The engine burns off-retrograde and then returns to retrograde. This is also somewhat shown by how the stage appears to move toward the center of the frame while it is aimed retrograde and then it is not doing that while it is thrusting off retrograde.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: AC in NC on 05/29/2016 08:56 pm
I want to dispel that idea and note that when the stage re-orients during its descent for the re-entry burn, this is done to avoid drifting of the IIP (Instantaneous Impact Point) of the stage. The engine burns off-retrograde and then returns to retrograde.

Excellent post and I actually think I understand it.   :o
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Elladan on 05/30/2016 01:34 am
I was curious to figure out how fast they sped up the landing video, so I did some quick calculations from the webcast video.

[...]

So ROUGHLY it looks like they sped the video up by 12x.  Too bad YouTube doesn't have an option for us to set the playback speed that low.  :P

Using your 12x value, I've used a video interpolation tool to slow the video down by 12x and insert interpolated frames in between (attached).

It came out a little muddy, but it's fun to watch!

Edit: In case you have trouble with the mp4 file, here's a YouTube version: https://www.youtube.com/watch?v=RY7MPAkMCuA
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meekGee on 05/30/2016 02:21 am
I was curious to figure out how fast they sped up the landing video, so I did some quick calculations from the webcast video.

[...]

So ROUGHLY it looks like they sped the video up by 12x.  Too bad YouTube doesn't have an option for us to set the playback speed that low.  :P

Using your 12x value, I've used a video interpolation tool to slow the video down by 12x and insert interpolated frames in between (attached).

It came out a little muddy, but it's fun to watch!

Magic fire!   cool.

I find it interesting that the grid fins activate on the dot when the engines turn off.

I think this corroborates the notion that the engines protect the rest of the rocket from the flow.

Also, clearly the engines provide control during that phase - perhaps the fins don't get enough bite at that point, but the body is large enough that it does, so tumbling is an issue.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: the_other_Doug on 05/30/2016 03:22 am
Hmm...  I have several media players that can play .mp4 files, and each of them starts this file up and then immediately say it's done.  They also say the file runs zero seconds.

Since others can watch it, I'm chalking it up to some issue with my media players.  And it's not like I haven't seen this video, just not this version of it.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: FutureSpaceTourist on 05/30/2016 05:45 am
I haven't seen any discussion of the press kit saying MECO would be at 2:35 but it was actually more like 2:42.

I know timings in the press kit are approximate but given they had bothered to change the MECO by a few seconds from the previous launch's press kit, 7s off seems a lot?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Steven Pietrobon on 05/30/2016 07:10 am
I believe part of the seven second  delay we are seeing is from the onboard video. A comparison

        Press Kit   YouTube  View
SES 9     2:36       2:39   Ground
JCSat 14  2:38       2:39   Ground
Thaicom 8 2:35       2:42   Vehicle


SpaceX might have added a delay as well so that they can cut the video before anyone sees any kabloomy goodness.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rocx on 05/30/2016 08:17 am
But kabloomy goodness is half the reason we watch rocket launches! We should just crowdfund to compensate the loss of a launch failure, as long as we get to see the explosions live from all angles.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: PlanetStorm on 05/30/2016 08:54 am
But kabloomy goodness is half the reason we watch rocket launches! We should just crowdfund to compensate the loss of a launch failure, as long as we get to see the explosions live from all angles.

Not for me it isn't. I imagine you said that in jest, but remember, some people have watched loved ones die. Others have watched in despair as they see the destruction of years of effort, the investment of a large part of their working career in designing and building a satellite coming to nothing. 
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rpapo on 05/30/2016 09:07 am
Using your 12x value, I've used a video interpolation tool to slow the video down by 12x and insert interpolated frames in between (attached).
I think this video settles one question reasonably well: most of the soot deposition and charring appears to be from reentry, not from the entry burn and certainly not from the launch burn.  The grid fins are clean during the stage flip, slightly darkened from the reentry burn, and quite charred after reentry has taken place.  All of which is of a piece with the smoky haze we see during reentry.  The wonder is that the supersonic air flow somehow cleans the camera lens before landing.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: gospacex on 05/30/2016 09:44 am
But kabloomy goodness is half the reason we watch rocket launches! We should just crowdfund to compensate the loss of a launch failure, as long as we get to see the explosions live from all angles.

Not for me it isn't. I imagine you said that in jest, but remember, some people have watched loved ones die. Others have watched in despair as they see the destruction of years of effort, the investment of a large part of their working career in designing and building a satellite coming to nothing.

If they don't want to see a possible kaboom, they should just avoid watching the launch live. Can always watch a successful launch afterwards.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: chalz on 05/30/2016 10:24 am
But kabloomy goodness is half the reason we watch rocket launches! We should just crowdfund to compensate the loss of a launch failure, as long as we get to see the explosions live from all angles.

Not for me it isn't. I imagine you said that in jest, but remember, some people have watched loved ones die. Others have watched in despair as they see the destruction of years of effort, the investment of a large part of their working career in designing and building a satellite coming to nothing.

If they don't want to see a possible kaboom, they should just avoid watching the launch live. Can always watch a successful launch afterwards.
That epically misses the point. PlanetStorm pointed out that a launch accident will affect some people personally and does not want to forget that. Those people will be affected whether they happen to watch it live or not! Retaining empathy for people in their position and not relishing in destruction seems a fine, humane response. Other opinions are available.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: ugordan on 05/30/2016 10:35 am
SpaceX might have added a delay as well so that they can cut the video before anyone sees any kabloomy goodness.

Or... it's just the nature of reassembling telemetry packets and processing MP4-type video streams across several pipelines. ULA telemetry visualizations have a similar 4 second delay probably for the same reasons.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: douglas100 on 05/30/2016 11:48 am

I think this video settles one question reasonably well: most of the soot deposition and charring appears to be from reentry, not from the entry burn and certainly not from the launch burn.  The grid fins are clean during the stage flip, slightly darkened from the reentry burn, and quite charred after reentry has taken place.  All of which is of a piece with the smoky haze we see during reentry.  The wonder is that the supersonic air flow somehow cleans the camera lens before landing.

Tend to agree. It looks like most of the discoloration on the RP-1 tank is charring. Whether this is an ablator or just paint isn't clear. If it's ordinary paint then presumably the low temperature at the bottom of the LOX tank prevents charring there and produces the sharp boundary that's seen on every flight.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mongo62 on 05/30/2016 12:20 pm
So ROUGHLY it looks like they sped the video up by 12x.  Too bad YouTube doesn't have an option for us to set the playback speed that low.  :P

Using your 12x value, I've used a video interpolation tool to slow the video down by 12x and insert interpolated frames in between (attached).

I certainly looks to me like the frame selection rate is not the same through the released video. It is probably around every 12th frame on average, but the landing burn appears to be significantly oversampled (it lasts 44 seconds in the interpolated video), while conversely the descent through the lower atmosphere appears to be undersampled.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: DrLucky on 05/30/2016 04:43 pm
Using your 12x value, I've used a video interpolation tool to slow the video down by 12x and insert interpolated frames in between (attached).
I think this video settles one question reasonably well: most of the soot deposition and charring appears to be from reentry, not from the entry burn and certainly not from the launch burn.  The grid fins are clean during the stage flip, slightly darkened from the reentry burn, and quite charred after reentry has taken place.  All of which is of a piece with the smoky haze we see during reentry.  The wonder is that the supersonic air flow somehow cleans the camera lens before landing.

I had assumed that SpaceX were using a removable protective film or layer which is either passively removed by increasing drag, or commanded to be removed.  Sort of akin to the camera protective films used on race cars.

I don't have any evidence to back this up, other than the frames of the landing video in which the obstructions seem to peel away, and the guess that some of the material (residue from ablative fin coatings, eg) deposited on the camera lens cover ought to be extremely difficult to remove cleanly.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: nicp on 05/30/2016 04:47 pm
If I recall correctly the early F9 ocean 'landings' with on board footage did not have the lens clear late on. So I agree - there must me some active 'race car' cam type film removal or cleaning going on.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: hrissan on 05/30/2016 06:10 pm
There has been some discussion that the rocket is not aimed retrograde during it's descent. I want to dispel that idea and note that when the stage re-orients during its descent for the re-entry burn, this is done to avoid drifting of the IIP (Instantaneous Impact Point) of the stage. The engine burns off-retrograde and then returns to retrograde. This is also somewhat shown by how the stage appears to move toward the center of the frame while it is aimed retrograde and then it is not doing that while it is thrusting off retrograde.
But it seems the stage is flying with its side forward before reorienting for entry burn?

So while the atmosphere is not dense enough to hurt it uses maximum possible air breaking area...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: wannamoonbase on 05/30/2016 06:24 pm
If I recall correctly the early F9 ocean 'landings' with on board footage did not have the lens clear late on. So I agree - there must me some active 'race car' cam type film removal or cleaning going on.

A changeable lens that handles re-entry heating. 

I thought that was pretty cool.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/30/2016 06:33 pm
There has been some discussion that the rocket is not aimed retrograde during it's descent. I want to dispel that idea and note that when the stage re-orients during its descent for the re-entry burn, this is done to avoid drifting of the IIP (Instantaneous Impact Point) of the stage. The engine burns off-retrograde and then returns to retrograde. This is also somewhat shown by how the stage appears to move toward the center of the frame while it is aimed retrograde and then it is not doing that while it is thrusting off retrograde.
But it seems the stage is flying with its side forward before reorienting for entry burn?

So while the atmosphere is not dense enough to hurt it uses maximum possible air breaking area...

No, it just hasn't finished reorienting itself.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rpapo on 05/30/2016 06:54 pm
No, it just hasn't finished reorienting itself.
From a thruster fuel perspective, there is no value in making the reorientation go faster than it needs to.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: the_other_Doug on 05/30/2016 06:57 pm
My take on the temporary occlusion of the rocket cam's field of view is that something (a strip of insulation, possibly) came up and flattened itself onto the camera's lens port.  A few seconds later, it got pulled off by increasing aerodynamic force on the vehicle, and after that most of the crud covering the camera port was blown/eroded off.

I'd also say that there was likely a clear port in the side of the rocket, behind which the camera was set.  I doubt we ever see any direct interaction between the actual camera lens and anything outside of the vehicle -- think of it as the camera looks out a little window, and sometimes stuff comes up and cruds over the window.  Then, later, wind blows the window clean... :)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: BigDustyman on 05/30/2016 07:02 pm
in the webcast one of the engineers mentioned a moving film like they use in nascar
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: AC in NC on 05/30/2016 07:05 pm
It did seem to me that it was not a continuous reorientation.  Seemed to spend more than instantaneous at about perpendiculat to retrograde.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mvpel on 05/30/2016 07:42 pm
It did seem to me that it was not a continuous reorientation.  Seemed to spend more than instantaneous at about perpendiculat to retrograde.

I suppose that could be an optical illusion. Remember, the trajectory of the booster is not a straight line and not parallel to the surface of the earth as in an orbit.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: catdlr on 05/31/2016 03:55 am
SpaceX - Elons' Word 05-28-2016

USLaunchReport

Published on May 30, 2016
SpaceX has launched and landed another booster. Do we become complacent with launches and landings, or do we listen when Elon speaks. By setting the original goal, Colonize Mars; we believe it is a part of our DNA to follow and be there.

https://www.youtube.com/watch?v=wpyDlLqb2oU?t=001

https://www.youtube.com/watch?v=wpyDlLqb2oU
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Liryc on 05/31/2016 09:12 am
Hi,

I was looking at the landing video : https://www.youtube.com/watch?v=4jEz03Z8azc#t=24
and I saw some outgasing at t=28sec.

I haven't seen anywhere on this discussion (or I missed it) but do you know what that would be ?
It seems rather short and soon after landing for a tank emptying procedure + it comes from the attitude control hole. Do you have any idea ?

Do you know what kind of gaz they use for attitude control ? (gaz from the oxygen or hydrogen tanks or some specific gaz ?)

Thanks !

P.S : any hotos or videos of the launcher return to the main land ?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Welsh Dragon on 05/31/2016 09:45 am
The thrusters are cold nitrogen. Not sure about the post-landing outgassing, would guess oxygen tank depressurisation?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Glom on 05/31/2016 09:49 am
That is so surreal.

What does it say on the landing deck? I couldn't quite make it out.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: DaveS on 05/31/2016 09:55 am
That is so surreal.

What does it say on the landing deck? I couldn't quite make it out.
It's the name of the ASDS, Of Course I still Love You.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: mvpel on 05/31/2016 12:22 pm
Post landing jet may have been a reaction to crush core-related tipping about which Elon Tweeted.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rpapo on 05/31/2016 12:26 pm
Post landing jet may have been a reaction to crush core-related tipping about which Elon Tweeted.
Very much like what happened with CRS-6, where the stage desperately tried to right itself.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rsdavis9 on 05/31/2016 01:10 pm
This may not be the correct place to post...

Is there a table of launches and meco velocity, time, altitude?
I get from watching the thaicom video:
2317m/s 65.9km 240s
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: MarsInMyLifetime on 05/31/2016 03:45 pm
Post landing jet may have been a reaction to crush core-related tipping about which Elon Tweeted.
Another possibility is that this is the post-landing LOX dump operation.



Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 05/31/2016 04:42 pm
Post landing jet may have been a reaction to crush core-related tipping about which Elon Tweeted.
Another possibility is that this is the post-landing LOX dump operation.

No, this burst was from the RCS, so it was Nitrogen. We have seen before that the RCS system is vented after landing.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: MarsInMyLifetime on 05/31/2016 06:45 pm
I verified this through comparison of an obvious RCS burst at landing with the venting event. Thanks for the clarification.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Rhyshaelkan on 05/31/2016 07:37 pm
Did she stay upright on the voyage home?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lar on 05/31/2016 07:40 pm
Did she stay upright on the voyage home?
Rumor has it we'll find out in 12 hours or less...

see  http://forum.nasaspaceflight.com/index.php?topic=40393
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jarnis on 05/31/2016 08:33 pm
Did she stay upright on the voyage home?

Yes.

http://i.imgur.com/I0HZgxL.jpg
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Bubbinski on 05/31/2016 08:35 pm
I would have thought if it had tipped over there'd be some kind of indication by now (tweet, warning over the nautical equivalent of NOTAMS of a hazard to navigation, something here or on Reddit, etc). Of course it was the Memorial Day weekend too, so maybe that would preclude getting info from the usual channels?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lar on 05/31/2016 08:54 pm
Did she stay upright on the voyage home?

Yes.

http://i.imgur.com/I0HZgxL.jpg

Is that imgur link the same image you shared in this post, Jarnis?
http://forum.nasaspaceflight.com/index.php?topic=40393.msg1542821#msg1542821

(Imgur is blocked at this client... told them I just wanted to look at rocket porn but that didn't fly)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: ricmsmith on 05/31/2016 08:58 pm
Post landing jet may have been a reaction to crush core-related tipping about which Elon Tweeted.
Another possibility is that this is the post-landing LOX dump operation.

I'm fairly sure it's something like that, I remember seeing it on each landing.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: docteurgeek on 05/31/2016 10:09 pm
Releasing lox is the last thing you want to do with a burning fire just near! Maybe nitrogen ...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jarnis on 06/01/2016 05:01 am
Did she stay upright on the voyage home?

Yes.

http://i.imgur.com/I0HZgxL.jpg

Is that imgur link the same image you shared in this post, Jarnis?
http://forum.nasaspaceflight.com/index.php?topic=40393.msg1542821#msg1542821

(Imgur is blocked at this client... told them I just wanted to look at rocket porn but that didn't fly)

Yes, didn't want to re-download and reattach the photo since I already did that once to ensure it is saved (and deleted it locally) so I just put a link.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: kdhilliard on 06/01/2016 04:25 pm
What would cause n2yo to give these strange numbers?

  http://www.n2yo.com/satellite/?s=41552
  Thaicom 8 / NORAD ID: 41552
  Perigee: -6,371.0 km
  Apogee: -6,371.0 km
  Inclination: 7.0
  Period: 0.0 minutes

Back on Saturday, 2016-05-28 04:07:07 it was showing a good supersynchronous orbit:
  41552:     354.6 km x 90,197.6 km @ 21.2 / 1,946.8 minutes

~Kirk
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Mike_1179 on 06/01/2016 04:44 pm
6,371 km is the radius of the Earth, so unless professor Otto Lidenbrock is there, it looks like they have no data on the satellite because it maneuvered. Need to wait for new data and they can publish new elements.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: the_other_Doug on 06/01/2016 04:50 pm
Either that or they are accidentally giving the location of Thaicom 9, still in its factory being constructed...
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: kevin-rf on 06/01/2016 05:02 pm
Wouldn't a negative be the earth's core and not the factory?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: pericynthion on 06/01/2016 06:20 pm
What would cause n2yo to give these strange numbers?

  http://www.n2yo.com/satellite/?s=41552
  Thaicom 8 / NORAD ID: 41552
  Perigee: -6,371.0 km
  Apogee: -6,371.0 km
  Inclination: 7.0
  Period: 0.0 minutes

Back on Saturday, 2016-05-28 04:07:07 it was showing a good supersynchronous orbit:
  41552:     354.6 km x 90,197.6 km @ 21.2 / 1,946.8 minutes

~Kirk

Its TLE looks legit in Celestrak (https://celestrak.com/cgi-bin/TLE.pl?CATNR=41552), so probably an n2yo bug.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: eeergo on 06/02/2016 06:40 pm
Unless I've missed it, I haven't seen a clear analysis on what happened to the camera on descent that made it (suddenly) lose the fogginess it acquired from re-entry. There was talk of a "rolling film" ( la NASCAR) that kept the lens clean, but I don't think it's the system at play here.


In fact, I'm inclined to think it was just an accident that the view cleared up so much!


It looks to my eye that the protective glass on the casing was just shattered inwards by the re-entry forces and possibly the TPS peppering it, while the camera was just able to withstand the remaining entry environment.


See the attached pictures for 1) worst-case fogged up view; 2) crack develops; 3) chipped glass in the center of the frame; 4) blow-in of the shards; 5) shards rattling around in the casing; 6) shards blown away from FOV; 7) camera fogs up again (and image rattles, consistent with an unintended wind buffeting on the camera structure). View clears up again around Max-Q, which I infer to happen around the time the Prandt-Glauert singularities appear around the fins.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: saliva_sweet on 06/02/2016 07:26 pm
This fogging up was first seen on CRS-4, after which IIRC Elon tweeted that they will add rolling film in front of the camera to keep the view clean. Also, in the hosted webcast it they said that this camera will get dirty, but not to worry, they will clean the camera after reentry and will show as much as they can (they didn't show this view later on the live webcast though).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: eeergo on 06/02/2016 07:42 pm
This fogging up was first seen on CRS-4, after which IIRC Elon tweeted that they will add rolling film in front of the camera to keep the view clean. Also, in the hosted webcast it they said that this camera will get dirty, but not to worry, they will clean the camera after reentry and will show as much as they can (they didn't show this view later on the live webcast though).

I agree they did mention some fogging was expected and would be cleared later on... but if I'm not mistaken there hasn't yet been any (published) event showing this "cracking" + sudden clearing up with pieces flying around + re-fogging + clearing up again.

In the experimental landings where we saw this onboard view there was a minor clearing with lots of ice present (Orbcomm, v=CQnR5fhCXkQ) or some debris that also looked like cracking but an otherwise clearer view (CRS-8, v=Z587WYqUDZI). The CRS-3 restored video (v=CjZ33C9JZTM) didn't show any fogging at landing but that may have had a different entry regime or camera position since it was one of the first landing attempts.

Maybe the external window *was* supposed to shatter, clearing the TPS impingement - but the rattling and the lingering of the fragments make me suspect it wasn't.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: tinorex on 06/04/2016 11:11 am
Here's my estimation of the delta-v required to establish GEO from the supersynchronous Thaicom-8 orbit. The inclination change is split optimally between the apogee and circularization burns

I find that lowest delta-v is aprox. 1487 m/s doing 94% of the inclination change during the apogee burn and the remaining 6% at circularization.
Excellent estimation.

n2yo:
Perigee: 37,866.6 km 
Apogee: 97,684.0 km 
Inclination: 1.4
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/04/2016 01:06 pm
Excellent estimation.

n2yo:
Perigee: 37,866.6 km 
Apogee: 97,684.0 km 
Inclination: 1.4

So perigee is finally near GEO altitude.

I wonder why they take so long / use so many maneuvers to establish GEO. My delta-v estimation assumed they did it using the minimum of two burns, and the whole transfer to GEO took about 41 hours:

(http://i.imgur.com/pPuzJnum.png) (http://i.imgur.com/pPuzJnu.png)

My guess is that they can only do continuous burns for a limited time so they split the maneuvers up.

So far these are the orbits we've seen:

350 x 90226 km, 21.22 (launch)
13057 x 90444, 6.96
37866.6 x 97684.0, 1.4

It's also weird that apogee increased 7000 km in the last maneuver (the NORAD TLE (https://www.celestrak.com/NORAD/elements/tle-new.txt) confirms it).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 06/04/2016 01:12 pm
Excellent estimation.

n2yo:
Perigee: 37,866.6 km 
Apogee: 97,684.0 km 
Inclination: 1.4

So perigee is finally near GEO altitude.

I wonder why they take so long / use so many maneuvers to establish GEO. My delta-v estimation assumed they did it using the minimum of two burns, and the whole transfer to GEO took about 41 hours:

(http://i.imgur.com/pPuzJnum.png) (http://i.imgur.com/pPuzJnu.png)

My guess is that they can only do continuous burns for a limited time so they split the maneuvers up.

So far these are the orbits we've seen:

350 x 90226 km, 21.22 (launch)
13057 x 90444, 6.96
37866.6 x 97684.0, 1.4

It's also weird that apogee increased 7000 km in the last maneuver (the NORAD TLE (https://www.celestrak.com/NORAD/elements/tle-new.txt) confirms it).


Because real-life dV doesn't happen instantaneously. Any maneuvers performed at the off-optimal time is unavoidably inefficient. If you aren't in a terrible hurry, it's more efficient to use multiple smaller maneuvers, each timed as close as possible to bracket that optimal instant. Remember, these satellites have a lifetime on the order of 12 - 15 years or more. Spending a few weeks to get to its assigned GSO slot is nothing, especially since there's already typically a month or two of activation and checkout after launch before the satellite can go into commercial service anyway.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: macpacheco on 06/04/2016 01:49 pm
Because real-life dV doesn't happen instantaneously. Any maneuvers performed at the off-optimal time is unavoidably inefficient. If you aren't in a terrible hurry, it's more efficient to use multiple smaller maneuvers, each timed as close as possible to bracket that optimal instant. Remember, these satellites have a lifetime on the order of 12 - 15 years or more. Spending a few weeks to get to its assigned GSO slot is nothing, especially since there's already typically a month or two of activation and checkout after launch before the satellite can go into commercial service anyway.
How about the time to arrive at the proper GEO station ?
Does this happen after the inclination, apogee and perigee is correct or is it mixed in somehow ?
Or perhaps part of the timing is such that the manuevers are completed such that the bird arrives at the right station ?
Just thinking out loud, don't know a think for a fact about this.
thanks.

PS: Posted to the Thaicom-8 UPDATEs thread, then I realized this isn't an update at all. Questions here (DISCUSSION), UPDATEs only there. Moved.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/04/2016 02:05 pm
Excellent estimation.

n2yo:
Perigee: 37,866.6 km 
Apogee: 97,684.0 km 
Inclination: 1.4

So perigee is finally near GEO altitude.

I wonder why they take so long / use so many maneuvers to establish GEO. My delta-v estimation assumed they did it using the minimum of two burns, and the whole transfer to GEO took about 41 hours:

(http://i.imgur.com/pPuzJnum.png) (http://i.imgur.com/pPuzJnu.png)

My guess is that they can only do continuous burns for a limited time so they split the maneuvers up.

So far these are the orbits we've seen:

350 x 90226 km, 21.22 (launch)
13057 x 90444, 6.96
37866.6 x 97684.0, 1.4

It's also weird that apogee increased 7000 km in the last maneuver (the NORAD TLE (https://www.celestrak.com/NORAD/elements/tle-new.txt) confirms it).


Because real-life dV doesn't happen instantaneously. Any maneuvers performed at the off-optimal time is unavoidably inefficient. If you aren't in a terrible hurry, it's more efficient to use multiple smaller maneuvers, each timed as close as possible to bracket that optimal instant. Remember, these satellites have a lifetime on the order of 12 - 15 years or more. Spending a few weeks to get to its assigned GSO slot is nothing, especially since there's already typically a month or two of activation and checkout after launch before the satellite can go into commercial service anyway.

(NOTE: moving this discussion from the UPDATES thread.)

That's a good point, but my impression was that at these altitudes the spacecraft is moving slow enough that it can do long burns and still be very close to the impulsive approximation.

But I hadn't really estimated how long these burns actually are. Thaicom-8 has a launch mass of about 3100 kg and uses the 450 N, 329 s BT-4 engine (SF101 (http://spaceflight101.com/falcon-9-thaicom-8/thaicom-8/)). Using these numbers, a 1000 m/s maneuver (approx. my estimated apogee maneuver) would take about ... 5923 seconds ... about 1.6 hours. That's really long!

While it's long, it's not *that* long at apogee of a 16-hour orbit. So perhaps it's a bit of both: engine burn-time limitations and minimizing the departure from the impulsive approximation?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/04/2016 02:10 pm
How about the time to arrive at the proper GEO station ?
Does this happen after the inclination, apogee and perigee is correct or is it mixed in somehow ?
Or perhaps part of the timing is such that the manuevers are completed such that the bird arrives at the right station ?
Just thinking out loud, don't know a think for a fact about this.
thanks.

Timing is important to get the sat to its proper place in GEO, true, but you can simply move the launch window to acommodate any mission profile. That is, the planned trajectory defines the launch window, not the other way around.

PS: thanks for pointing out we were posting in the wrong thread. Let's continue the discussion here. I hope Herb notices.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 06/04/2016 02:36 pm
While it's long, it's not *that* long at apogee of a 16-hour orbit. So perhaps it's a bit of both: engine burn-time limitations and minimizing the departure from the impulsive approximation?

That's a long time for any number of other reasons - dynamic (vibration + duration) load limits, almost certainly thermal limits, etc.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/04/2016 03:09 pm
While it's long, it's not *that* long at apogee of a 16-hour orbit. So perhaps it's a bit of both: engine burn-time limitations and minimizing the departure from the impulsive approximation?

That's a long time for any number of other reasons - dynamic (vibration + duration) load limits, almost certainly thermal limits, etc.

Yes, I agree: my intuition was that it was more a spacecraft/engine limitation than something related to finite burn inefficiency (orbital mechanics).

I found a paper (http://central.oak.go.kr/journallist/articlepdf.do?url=/repository/journal/10809/OJOOBS_2011_v28n3_203.pdf&article_seq=10809) that analyzes finite-burn losses in a lunar-orbit capture for a ~840 kg hypothetical spacecraft using a similar 450 N engine (Thaicom-8 weighs about 4 times more than that, so it only manages about 1/4 as much acceleration). They find that a 6.5-minutes 355 m/s burn (with the burn started half the burn time before perilune - nice to see this confirmed) incurs less than 1% finite-burn losses compared to the ideal impulsive maneuver. While I don't know how this scales to Thaicom-8's situation, I have a feeling that finite-burn losses are probably not large either.

I've always wanted to learn how to estimate finite-burn losses, but I suspect there's no simple approximation to it and one requires full-blown trajectory optimization software.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Jim on 06/04/2016 06:51 pm

Yes, I agree: my intuition was that it was more a spacecraft/engine limitation than something related to finite burn inefficiency (orbital mechanics).


No, it is  orbital mechanics and not spacecraft systems
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: baldusi on 06/04/2016 08:33 pm
Let's not forget the thermal and illumination requirements of the spacecrafts. That's why Ariane 5 has a 2hr launch window pero day.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/05/2016 12:15 am

Yes, I agree: my intuition was that it was more a spacecraft/engine limitation than something related to finite burn inefficiency (orbital mechanics).


No, it is  orbital mechanics and not spacecraft systems

Can you elaborate? Is it the finite-burn losses then?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: cuddihy on 06/05/2016 11:43 am
It's that you need to lower your inclination at apogee while passing through the equitorial plane. So if you can't do it all at once, you have to do each small part of it at apogee to be effective. On an orbit with GSO semi-major axis, by definition, you only hit apogee once a day, even less often on a supersynch GTO because it's farther out.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: CorvusCorax on 06/05/2016 12:09 pm

Yes, I agree: my intuition was that it was more a spacecraft/engine limitation than something related to finite burn inefficiency (orbital mechanics).


No, it is  orbital mechanics and not spacecraft systems

Can you elaborate? Is it the finite-burn losses then?

Timing.

The sattelite makes its final orbital insertion at perigee - at roughly 35700 km. This must happen very close or exactly at its intended orbital slot at 78.5

The launch window is not timed to get the sat to the perfect spot, but to optimize its thermal and solar exposure - so you launch in the evening, resulting in a "local midnight" second burn over the equator, to ensure apogee of the supersynchronous transfer orbit is on the sunny-side.

you could do a two impulse burn to get to GEO - one impulse to raise perigee to 35700 (and fix most of the inclination) the second to lower apogee down to GEO as well. That would get the sattelite to GEO the quickest, but it would end up in the wrong slot.

You also don't want to spend additional delta-v to move slots.

So the solution is to do the perigee raise in two halves - timed exactly such that the orbital period after the first raise will have the second raise one orbit later get you not only to the correct perigee but also reach that perigee exactly at 78.5 - the intended slot. Once there you only lower apogee and you're done.

You still did it very fast, you only used one additional orbit (less than a day) but more importantly, you did this synchronization with zero delta-v expense.

And from a supersynchronous GTO, you can use this trick to get to ANY slot from ANY original orbit, the only change is how you spread the ration between first and second perigee-raise and as such how much time you spend on the "waiting loop" in between these raises.


Edit: I blame SpaceX and their Zillion for getting my numbers wrong ;)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: baskerbosse on 06/06/2016 03:52 am
This fogging up was first seen on CRS-4, after which IIRC Elon tweeted that they will add rolling film in front of the camera to keep the view clean. Also, in the hosted webcast it they said that this camera will get dirty, but not to worry, they will clean the camera after reentry and will show as much as they can (they didn't show this view later on the live webcast though).

I found this too.
Sounds about right.
At about 28:40 in the hosted webcast:
https://www.youtube.com/watch?v=zBYC4f79iXc&t=1710s
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/06/2016 04:35 pm
Timing.
[...]
The launch window is not timed to get the sat to the perfect spot, but to optimize its thermal and solar exposure - so you launch in the evening, resulting in a "local midnight" second burn over the equator, to ensure apogee of the supersynchronous transfer orbit is on the sunny-side.
[...]
And from a supersynchronous GTO, you can use this trick to get to ANY slot from ANY original orbit, the only change is how you spread the ration between first and second perigee-raise and as such how much time you spend on the "waiting loop" in between these raises.

Mmmh, I admit you make a compelling case.

I understand that the thermal/solar exposure issue is important. It's why there's a launch window for GEO transfers in the first place: because the target orbital spot rotates with the Earth, without the thermal/solar restriction you could launch at any time whatsoever and the exact same transfer trajectory will take you to the target spot.

I guess having extra intermediate orbits also lets you correct for small deviations due to launcher injection errors or incurred during the large-ish apogee burn. And as somebody said before, these sats become operational *weeks* after launch, so there's no hurry in getting them to their GEO spot as soon as possible.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: DrLucky on 06/06/2016 05:29 pm

So far these are the orbits we've seen:

350 x 90226 km, 21.22 (launch)
13057 x 90444, 6.96
37866.6 x 97684.0, 1.4

It's also weird that apogee increased 7000 km in the last maneuver (the NORAD TLE (https://www.celestrak.com/NORAD/elements/tle-new.txt) confirms it).

I found the apogee raise interesting, too. 

If it was done intentionally with perigee burns at the very start of orbit raising, I think it's a push, or even slightly advantageous in terms of overall dV. 

Done later, it would be a waste of dV, I think.

Of course, a 90,000km apogee is also a quarter of the way to the moon.  Anyone notice if it got a gravity assist / perturbation?  Then again, wouldn't that mostly show up as a perigee raise? 

I'm spectacularly under-equipped to figure out where the moon was in relation to that orbit.

Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: kevin-rf on 06/06/2016 06:19 pm
Of course, a 90,000km apogee is also a quarter of the way to the moon.  Anyone notice if it got a gravity assist / perturbation?  Then again, wouldn't that mostly show up as a perigee raise? 
Just as a reminder, several years ago, an Atlas launched a GEO without taking into account lunar perturbations. It almost ended very badly, with the perigee dipping very, almost too low.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Lars-J on 06/06/2016 06:40 pm
Of course, a 90,000km apogee is also a quarter of the way to the moon.  Anyone notice if it got a gravity assist / perturbation?  Then again, wouldn't that mostly show up as a perigee raise? 
Just as a reminder, several years ago, an Atlas launched a GEO without taking into account lunar perturbations. It almost ended very badly, with the perigee dipping very, almost too low.

Which flight was that?
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ben the Space Brit on 06/06/2016 06:52 pm
I found the apogee raise interesting, too. 

If it was done intentionally with perigee burns at the very start of orbit raising, I think it's a push, or even slightly advantageous in terms of overall dV. 

Done later, it would be a waste of dV, I think.

It may have been a hazard avoidance measure - To keep the Falcon-9 upper-stage well away from the Clarke Ring so that it isn't a collision hazard. Not only with active spacecraft but also inactive ones that may have drifted away from their assigned retirement stations and are waiting to trigger a Kessler Syndrome if struck and knocked into other spacecraft (even a low-energy contact of a few metres per second might be enough).
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: kevin-rf on 06/06/2016 06:58 pm
Of course, a 90,000km apogee is also a quarter of the way to the moon.  Anyone notice if it got a gravity assist / perturbation?  Then again, wouldn't that mostly show up as a perigee raise? 
Just as a reminder, several years ago, an Atlas launched a GEO without taking into account lunar perturbations. It almost ended very badly, with the perigee dipping very, almost too low.

Which flight was that?

SuperBird 6, AC-163

http://space.skyrocket.de/doc_sdat/superbird-6.htm
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/06/2016 07:25 pm
It may have been a hazard avoidance measure - To keep the Falcon-9 upper-stage well away from the Clarke Ring so that it isn't a collision hazard. Not only with active spacecraft but also inactive ones that may have drifted away from their assigned retirement stations and are waiting to trigger a Kessler Syndrome if struck and knocked into other spacecraft (even a low-energy contact of a few metres per second might be enough).

Nope, we're discussing the orbit of Thaicom-8 (catalog number 41552) here, not of the Falcon 9 upper stage that launched it. NORAD still reports (https://www.celestrak.com/NORAD/elements/tle-new.txt) the Falcon 9 upper stage (catalog number 41553) on a 381.8 x 90935.0 km @ 21.12 orbit.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Herb Schaltegger on 06/06/2016 07:42 pm
[quote author=DrLucky
It may have been a hazard avoidance measure - To keep the Falcon-9 upper-stage well away from the Clarke Ring so that it isn't a collision hazard. Not only with active spacecraft but also inactive ones that may have drifted away from their assigned retirement stations and are waiting to trigger a Kessler Syndrome if struck and knocked into other spacecraft (even a low-energy contact of a few metres per second might be enough).

"Assigned retirement stations" are generally "graveyard orbits" several hundred kilometers above GSO.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: baldusi on 06/06/2016 08:05 pm
[quote author=DrLucky
It may have been a hazard avoidance measure - To keep the Falcon-9 upper-stage well away from the Clarke Ring so that it isn't a collision hazard. Not only with active spacecraft but also inactive ones that may have drifted away from their assigned retirement stations and are waiting to trigger a Kessler Syndrome if struck and knocked into other spacecraft (even a low-energy contact of a few metres per second might be enough).

"Assigned retirement stations" are generally "graveyard orbits" several hundred kilometers above GSO.
Specifically, the standard graveyard orbit is GSO+200km circular.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/06/2016 08:32 pm
I finally found a website that lists all past orbits for satellites: Zarya.info (http://www.zarya.info) :). Launches of 2016 here (http://www.zarya.info/Diaries/Launches/Launches.php?year=2016).

And it's reporting an updated orbit (http://www.zarya.info/Diaries/Launches/Launches.php?year=2016#031) today (monday 6th june) for our Thaicom-8: 35,887 x 43,303 km, 0.31. Seems the apogee is almost to geosynchronous altitude. One more maneuver?

Thaicom-8's orbit history is thus as follows:

Date (UTC)           Perigee  Apogee  Inclination
2016 May 27, 23:16   375      90928   21.12
2016 May 30, 16:00   13075    90292   6.95
2016 Jun 3, 08:21    37806    97550   1.42
2016 Jun 6, 14:20    35887    43303   0.31

Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ben the Space Brit on 06/07/2016 10:59 am
It may have been a hazard avoidance measure - To keep the Falcon-9 upper-stage well away from the Clarke Ring so that it isn't a collision hazard. Not only with active spacecraft but also inactive ones that may have drifted away from their assigned retirement stations and are waiting to trigger a Kessler Syndrome if struck and knocked into other spacecraft (even a low-energy contact of a few metres per second might be enough).

Nope, we're discussing the orbit of Thaicom-8 (catalog number 41552) here, not of the Falcon 9 upper stage that launched it. NORAD still reports (https://www.celestrak.com/NORAD/elements/tle-new.txt) the Falcon 9 upper stage (catalog number 41553) on a 381.8 x 90935.0 km @ 21.12 orbit.

I think that you misread my post. I'm taking about Thaicom-8's apogee-raising manoeuvre; why would it need a higher apogee than its insertion stage? I'm suggesting it's because they didn't want the insertion stage getting all the way up to the altitude of GSO.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: douglas100 on 06/07/2016 12:11 pm
It may have been a hazard avoidance measure - To keep the Falcon-9 upper-stage well away from the Clarke Ring so that it isn't a collision hazard. Not only with active spacecraft but also inactive ones that may have drifted away from their assigned retirement stations and are waiting to trigger a Kessler Syndrome if struck and knocked into other spacecraft (even a low-energy contact of a few metres per second might be enough).

Nope, we're discussing the orbit of Thaicom-8 (catalog number 41552) here, not of the Falcon 9 upper stage that launched it. NORAD still reports (https://www.celestrak.com/NORAD/elements/tle-new.txt) the Falcon 9 upper stage (catalog number 41553) on a 381.8 x 90935.0 km @ 21.12 orbit.

I think that you misread my post. I'm taking about Thaicom-8's apogee-raising manoeuvre; why would it need a higher apogee than its insertion stage? I'm suggesting it's because they didn't want the insertion stage getting all the way up to the altitude of GSO.

I think the misunderstanding arises from the use of the phrase "injection stage." Are you referring to the spacecraft, the Falcon second stage or the actual operation of injecting the spacecraft into its initial transfer orbit?

Quote
I'm suggesting it's because they didn't want the insertion stage getting all the way up to the altitude of GSO.I'm suggesting it's because they didn't want the insertion stage getting all the way up to the altitude of GSO.

(My bold.)
Look at the numbers meithan quoted. The apogees of both spacecraft and second stage were ~90,000km at spacecraft separation. So the "insertion stage" (however you define it) was already well above geosynchronous height.

It was nothing to do with collision avoidance. The initial transfer orbit was inclined to geosynchronous orbit so both stage and spacecraft would not pass anywhere near operational spacecraft. The chance of a collision would be vanishingly small.

The reason for the maneuvers is almost certainly to get the spacecraft to its slot reasonably quickly with the minimum delta V, as discussed upthread.

EDIT: added explanation.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Kabloona on 06/07/2016 12:33 pm
It may have been a hazard avoidance measure - To keep the Falcon-9 upper-stage well away from the Clarke Ring so that it isn't a collision hazard. Not only with active spacecraft but also inactive ones that may have drifted away from their assigned retirement stations and are waiting to trigger a Kessler Syndrome if struck and knocked into other spacecraft (even a low-energy contact of a few metres per second might be enough).

Nope, we're discussing the orbit of Thaicom-8 (catalog number 41552) here, not of the Falcon 9 upper stage that launched it. NORAD still reports (https://www.celestrak.com/NORAD/elements/tle-new.txt) the Falcon 9 upper stage (catalog number 41553) on a 381.8 x 90935.0 km @ 21.12 orbit.

I think that you misread my post. I'm taking about Thaicom-8's apogee-raising manoeuvre; why would it need a higher apogee than its insertion stage?

The very short answer is that a higher apogee gives a longer "lever arm" for plane change maneuvers, thus requiring less delta V from the satellite to rotate its plane from its parking orbit inclination down to zero degrees.

The savings gained there outweigh the small additional delta V needed to reduce apogee back down to GSO altitude after plane change and perigee raising are done.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/07/2016 01:30 pm
It may have been a hazard avoidance measure - To keep the Falcon-9 upper-stage well away from the Clarke Ring so that it isn't a collision hazard. Not only with active spacecraft but also inactive ones that may have drifted away from their assigned retirement stations and are waiting to trigger a Kessler Syndrome if struck and knocked into other spacecraft (even a low-energy contact of a few metres per second might be enough).

Nope, we're discussing the orbit of Thaicom-8 (catalog number 41552) here, not of the Falcon 9 upper stage that launched it. NORAD still reports (https://www.celestrak.com/NORAD/elements/tle-new.txt) the Falcon 9 upper stage (catalog number 41553) on a 381.8 x 90935.0 km @ 21.12 orbit.

I think that you misread my post. I'm taking about Thaicom-8's apogee-raising manoeuvre; why would it need a higher apogee than its insertion stage? I'm suggesting it's because they didn't want the insertion stage getting all the way up to the altitude of GSO.

Yep, you're right, I didn't quite understand what you were saying, sorry. I think douglas100 got it though: it seems you were under the impression that the initial apogee of 90,000 km was geosynchronous altitude. But nope, geosynchronous altitude is about 35,800 km. This apogee much higher than GEO is the reason this is called a "supersynchronous" transfer. And as Kabloona said, the advantage of a supersynchronous transfer is reducing the delta-v required for the inclination change.

Which brings us back to why they did that further 7,000 km apogee raise, a week after launch. I don't think it's to save further delta-v on inclination change; the inclination was already down to 7. I'm with douglas100: it's probably to adjust the orbital period so that it reaches the proper GEO slot at perigee.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: baldusi on 06/07/2016 02:31 pm
At those distances the moon might tug the satellite enough to lower its perigee to dangerous altitudes (anything below 150km). So increasing the perigee is critical.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris Bergin on 06/07/2016 07:26 pm
Worth noting per the thread conversation that a source of mine has noted that the 97550 km apogee reported by other sites is in error.

I'm told the apogee for that orbit was closer to the 90292 km reported for the previous orbit.  There was no maneuver by Thaicom-8 to increase apogee during this mission.

Source is very good, so there is no need to speculate further on this.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/07/2016 07:45 pm
Worth noting per the thread conversation that a source of mine has noted that the 97550 km apogee reported by other sites is in error.

I'm told the apogee for that orbit was closer to the 90292 km reported for the previous orbit.  There was no maneuver by Thaicom-8 to increase apogee during this mission.

Source is very good, so there is no need to speculate further on this.

Makes sense. Thanks a lot for the tip, Chris. I'm saving my pennies for an L2 account soon, where I'm sure all these details are well divulged.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: pericynthion on 06/07/2016 07:46 pm
If I may, I'll speculate on the source of the error - objects at such high altitudes aren't the easiest for JSpOC to track, for at least three reasons:
1. The r^4 loss at such distances gives poor SNR.
2. The long periods give infrequent opportunities to make new measurements.
3. Small errors in velocity at perigee result in large changes in estimated apogee.

Unfortunately JSpOC doesn't publish covariance (uncertainty) estimates along with the TLEs, but even for LEO they can have surprisingly large errors.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Chris Bergin on 06/07/2016 11:56 pm
Worth noting per the thread conversation that a source of mine has noted that the 97550 km apogee reported by other sites is in error.

I'm told the apogee for that orbit was closer to the 90292 km reported for the previous orbit.  There was no maneuver by Thaicom-8 to increase apogee during this mission.

Source is very good, so there is no need to speculate further on this.

Makes sense. Thanks a lot for the tip, Chris. I'm saving my pennies for an L2 account soon, where I'm sure all these details are well divulged.

Pleasure and just so there's no false advertising (heh), that was direct to the open site, not via L2. L2 is very cool, but we aim to make all of NSF very cool as a minimum goal. The above note was to correct public misinformation, thus is a direct response for this thread. :)
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: dcporter on 06/08/2016 06:17 am
Worth noting per the thread conversation that a source of mine has noted that the 97550 km apogee reported by other sites is in error.

I'm told the apogee for that orbit was closer to the 90292 km reported for the previous orbit.  There was no maneuver by Thaicom-8 to increase apogee during this mission.

Source is very good, so there is no need to speculate further on this.

Makes sense. Thanks a lot for the tip, Chris. I'm saving my pennies for an L2 account soon, where I'm sure all these details are well divulged.

Pleasure and just so there's no false advertising (heh), that was direct to the open site, not via L2. L2 is very cool, but we aim to make all of NSF very cool as a minimum goal. The above note was to correct public misinformation, thus is a direct response for this thread. :)

yea but also L2 is dope
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: meithan on 06/10/2016 01:03 pm
Seems our bird arrived to its nest on wednesday. Mean motion is now 0.99993250 revs/day.

Date (UTC)           Perigee  Apogee  Inclination
2016 May 27, 23:16   375      90928   21.12
2016 May 30, 16:00   13075    90292   6.95
2016 Jun 3, 08:21    37806    975501  1.42
2016 Jun 6, 14:20    35887    43303   0.31
2016 Jun 8, 00:34    35886    38731   0.13
2016 Jun 8, 19:04    35881    35892   0.03   80 east


1Reliable sources report this value is in error; actual apogee virtually unchanged compared to previous orbit.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Ronsmytheiii on 06/12/2016 06:39 pm
Not sure which core it is, but one of the returned Falcon 9 stages is leaving the LC-39A HIF

https://twitter.com/spacekscblog/status/742062804761448449
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rockets4life97 on 06/12/2016 06:46 pm
Not sure which core it is, but one of the returned Falcon 9 stages is leaving the LC-39A HIF

https://twitter.com/spacekscblog/status/742062804761448449

My guess is that it is the Orbcomm core. It was looking clean and ready to go to Hawthorne in the last published picture.
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: baldusi on 06/12/2016 09:44 pm
And they are ruining the Bingo thread name! Someone should talk with Elon!
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: Graham on 06/12/2016 09:49 pm
Not sure which core it is, but one of the returned Falcon 9 stages is leaving the LC-39A HIF

https://twitter.com/spacekscblog/status/742062804761448449

My guess is that it is the Orbcomm core. It was looking clean and ready to go to Hawthorne in the last published picture.

Stephen Smith tweeted that it was "not the cleaned up one". This means it is likely JCSAT or CRS 8 heading to McGregor

https://twitter.com/spacekscblog/status/742067468408094722
Title: Re: SpaceX Falcon-9 - Thaicom-8 - May 27, 2016 - DISCUSSION
Post by: rberry on 06/12/2016 09:55 pm
Not sure which core it is, but one of the returned Falcon 9 stages is leaving the LC-39A HIF

https://twitter.com/spacekscblog/status/742062804761448449

My guess is that it is the Orbcomm core. It was looking clean and ready to go to Hawthorne in the last published picture.

Stephen Smith tweeted that it was "not the cleaned up one". This means it is likely JCSAT

https://twitter.com/spacekscblog/status/742067468408094722

Based on picture evidence it looks like the only options are OG-2 or Thiacomm....

The way the stages are oriented in the HIF it would mean that CRS-8 and JCSAT-14 are the two stages visible to the the left of the truck. If it really isn't the cleaned up one (I have no reason to doubt Stephen Smith), then it would be Thiacomm.

Plus, discussing this here -> http://forum.nasaspaceflight.com/index.php?topic=39167.420