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SpaceX Vehicles and Missions => SpaceX Missions Section => Topic started by: gongora on 04/09/2017 01:32 AM

Title: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion Thread 1
Post by: gongora on 04/09/2017 01:32 AM
NSF Threads for Falcon Heavy Demo : Updates (https://forum.nasaspaceflight.com/index.php?topic=44376.0) / Discussion Thread 1 (https://forum.nasaspaceflight.com/index.php?topic=42705.0) / Discussion Thread 2 (http://forum.nasaspaceflight.com/index.php?topic=44778.0) / Member Meetup (http://forum.nasaspaceflight.com/index.php?topic=44587.0;topicseen) / Cape Canaveral Launch Viewing (http://forum.nasaspaceflight.com/index.php?topic=44657.msg1770088;topicseen#new) / FH Demo Mission Payload Discussion (http://forum.nasaspaceflight.com/index.php?topic=44375.0) / FH Demo Discussion and Speculation (http://forum.nasaspaceflight.com/index.php?topic=41454.0) / FH Demo Payload Speculation (https://forum.nasaspaceflight.com/index.php?topic=42801.0) / L2 Coverage November-December (https://forum.nasaspaceflight.com/index.php?topic=44111.0) - January-February (http://forum.nasaspaceflight.com/index.php?topic=44312.0) / ASDS (https://forum.nasaspaceflight.com/index.php?board=66.0) / Party (https://forum.nasaspaceflight.com/index.php?topic=40089.msg1520968#msg1520968)

NSF Articles for Falcon Heavy Demo :
   [April 12, 2017] Falcon Heavy build up begins; SLC-40 pad rebuild progressing well (https://www.nasaspaceflight.com/2017/04/falcon-heavy-build-up-slc-40-pad-rebuild-progressing/)
   [April 25, 2017] SpaceX Static Fire spy sat rocket and prepare to test Falcon Heavy core (https://www.nasaspaceflight.com/2017/04/spacex-static-fire-tests-spy-sat-rocket-falcon-heavy-core/)
   [Nov. 1, 2017] SpaceX aims for late-December launch of Falcon Heavy (https://www.nasaspaceflight.com/2017/11/spacex-aims-december-launch-falcon-heavy/)
   [Dec. 30, 2017] Falcon Heavy preparing for Static Fire test (https://www.nasaspaceflight.com/2017/12/falcon-heavy-maiden-static-fire-test/)
   [Jan. 24, 2018] Falcon Heavy comes to life as SpaceX conduct Static Fire test (https://www.nasaspaceflight.com/2018/01/spacex-static-fire-falcon-heavy-1/)
   [Feb. 5/6, 2018] SpaceX successfully debuts Falcon Heavy in demonstration launch from KSC (https://www.nasaspaceflight.com/2018/02/spacex-debut-falcon-heavy-demonstration-launch/)
   [Feb. 9, 2018] Falcon Heavy success paves the way for open access to space beyond Earth (https://www.nasaspaceflight.com/2018/02/falcon-heavy-success-paves-space-beyond-earth/)

Successful launch Feb 6th at 1545 EST/2045 UTC from LC-39A at KSC carrying Tesla Roadster with Starman mannequin (mass around 1200 kg?).  Launch vehicle used a new center booster (1033) and reused side boosters (1023.2, 1025.2).  The side boosters successfully landed back at LZ-1 and LZ-2 at CCAFS.  The center core crashed into the ocean very close to the ASDS.



Now that we're starting to see hardware flow for the first FH, let's keep discussion in this new mission thread a bit more focused.  Discussion here should be about stuff we actually know about the mission.  Any speculation about Dragons carrying school buses made of cheese will be deleted.  There is still a thread you can use for speculation (http://forum.nasaspaceflight.com/index.php?topic=41454.0).

We're waiting for photos, but Gary for L2 McGregor is reporting FH side booster on the test stand! :)



Other SpaceX resources on NASASpaceflight:
   SpaceX News Articles (Recent) (http://www.nasaspaceflight.com/tag/spacex/)  /   SpaceX News Articles from 2006 (Including numerous exclusive Elon interviews) (http://forum.nasaspaceflight.com/index.php?topic=21862.0)
   SpaceX Dragon Articles (http://www.nasaspaceflight.com/tag/dragon/)  /  SpaceX Missions Section (with Launch Manifest and info on past and future missions) (https://forum.nasaspaceflight.com/index.php?board=55.0)
   L2 SpaceX Section (https://forum.nasaspaceflight.com/index.php?board=60.0)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 04/09/2017 02:35 AM
Hi Res set from Gary Blair (taken from a public area...as always) going into L2 over the coming hours, but this is a big milestone, so passing on at least a preview as "Conehead" is cool.

We believe this is 1023 (formerly the leaning Tower of Thaicom-8). One of the two flight proven S1's that will be with the Falcon Heavy debut.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 04/09/2017 05:17 PM
"Conehead"  Very good.  "We're NOT from France!" ;)

It is interesting that the guy wires are attached outside of the cone. 
Would this make for more rapid processing, not needing to take off the cone for test firing? 
Can they transport the stage from Hawthorne and to Florida with the cone attached? 
Isn't it said that the first stage is already at the length limit for transport? 
If they have to take off the cone for transport, why not use the standard (or slightly modified) cap for test firing? 
Why build this capability into flight hardware?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cppetrie on 04/09/2017 05:23 PM
"Conehead"  Very good.  "We're NOT from France!" ;)

It is interesting that the guy wires are attached outside of the cone. 
Would this make for more rapid processing, not needing to take off the cone for test firing? 
Can they transport the stage from Hawthorne and to Florida with the cone attached? 
Isn't it said that the first stage is already at the length limit for transport? 
If they have to take off the cone for transport, why not use the standard (or slightly modified) cap for test firing? 
Why build this capability into flight hardware?
Does the first stage normally transports with an interstage? If so, it might be that the cone replaces the interstage and doesn't add to the overall length of the rocket for transport. There is no reason for the nosecap to be easily removable since it isn't coming off inflight so it makes some sense to attach it semi-permanently at the factory and design a rig for testing with the cone already in place.

Just my 2 cents.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rberry on 04/09/2017 05:30 PM
"Conehead"  Very good.  "We're NOT from France!" ;)

It is interesting that the guy wires are attached outside of the cone. 
Would this make for more rapid processing, not needing to take off the cone for test firing? 
Can they transport the stage from Hawthorne and to Florida with the cone attached? 
Isn't it said that the first stage is already at the length limit for transport? 
If they have to take off the cone for transport, why not use the standard (or slightly modified) cap for test firing? 
Why build this capability into flight hardware?

I believe it was transported from Hawthorne to McGregor with the nose cone attached, so presumably it could also be transported to Florida.

*Edit Attached Image https://imgur.com/a/Vbxrx#zPdInH5
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 04/09/2017 05:43 PM
Does the first stage normally transports with an interstage?

Yes.

If so, it might be that the cone replaces the interstage and doesn't add to the overall length of the rocket for transport.

The nose cone replaces the interstage, and it appears to be quite a bit shorter.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 04/09/2017 11:33 PM
"Conehead"  Very good.  "We're NOT from France!" ;)

It is interesting that the guy wires are attached outside of the cone. 
Would this make for more rapid processing, not needing to take off the cone for test firing? 
Can they transport the stage from Hawthorne and to Florida with the cone attached? 
Isn't it said that the first stage is already at the length limit for transport? 
If they have to take off the cone for transport, why not use the standard (or slightly modified) cap for test firing? 
Why build this capability into flight hardware?

I believe it was transported from Hawthorne to McGregor with the nose cone attached, so presumably it could also be transported to Florida.

I didn't "fix" your quote.  Just colored it. ;)
I had forgotten that photo.  Thanks
So what are people's opinion of having the hold-down's as part of the "conehead"?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cppetrie on 04/09/2017 11:42 PM
So what are people's opinion of having the hold-down's as part of the "conehead"?

I don't think there are hard connections from the wires to the cone. It looks like there is just the gray metal ring that "sits" on/around the cone and the wires attach to the ring. Since the ring sits nearly all the way down where the cone attaches to the stage it should be able to carry the load into the stage without fixed attachment points. Think of it as a crown for the conehead. That's my impression from the photo anyway.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 04/12/2017 06:58 PM
Article for the side booster at McGregor, by Chris Gebhardt:

https://www.nasaspaceflight.com/2017/04/falcon-heavy-build-up-slc-40-pad-rebuild-progressing/

1023.2 may static fire at McGregor as early as today (Wednesday).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vaporcobra on 04/18/2017 06:21 AM
In light of reports that a core stage may have been set to static fire last week, I browsed the SpaceX tag on Instagram and came across this. Photo posted (not sure if taken) Saturday of the McGregor test site, and strongly suggests that 1023.2 did indeed have an apparently successful SF.

https://www.instagram.com/p/BS6nzBPDwed/
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: DLK on 04/18/2017 03:41 PM
It appears that it 'consumed mass quantites' of propellant indeed.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Flying Beaver on 04/18/2017 03:45 PM
In light of reports that a core stage may have been set to static fire last week, I browsed the SpaceX tag on Instagram and came across this. Photo posted (not sure if taken) Saturday of the McGregor test site, and strongly suggests that 1023.2 did indeed have an apparently successful SF.

https://www.instagram.com/p/BS6nzBPDwed/

Wrong stand. You can see the old tripod stand to the right, the booster stand is right beside it, further to the right out of frame.

This test's vapor plume is better placed for Raptor, as it's stand is a ways to the north of the booster, as well as Merlin, testing areas.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 04/18/2017 04:51 PM
In light of reports that a core stage may have been set to static fire last week, I browsed the SpaceX tag on Instagram and came across this. Photo posted (not sure if taken) Saturday of the McGregor test site, and strongly suggests that 1023.2 did indeed have an apparently successful SF.

https://www.instagram.com/p/BS6nzBPDwed/

Wrong stand. You can see the old tripod stand to the right, the booster stand is right beside it, further to the right out of frame.

This test's vapor plume is better placed for Raptor, as it's stand is a ways to the north of the booster, as well as Merlin, testing areas.

With the water tower on the right of the tripod, this is likely looking south-ish, not north. Meaning the plume is probably coming from the small site where they test Merlins.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Flying Beaver on 04/18/2017 10:37 PM
Interesting note on the supposed FH core sighted yesterday. Around the aft engine section there seems to be loads of coloured tape.

Without a closer look it's only guessing, but I was thinking they could be messages from Hawthorne employees, sending the first FH core on it's way.

It's a bit out there ;D

From here: https://www.reddit.com/r/spacex/comments/65z8yi/falcon_spotting_sighting_in_marana_az_im_pretty/?ref=share&ref_source=link (https://www.reddit.com/r/spacex/comments/65z8yi/falcon_spotting_sighting_in_marana_az_im_pretty/?ref=share&ref_source=link)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ronsmytheiii on 04/19/2017 04:19 PM
Here is an image of the core back at Hawthorne:

https://www.instagram.com/roninchausti/

Edit more:

https://www.instagram.com/p/BS-PgO-FX6L/
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: enzo on 04/21/2017 04:31 AM
Interesting note on the supposed FH core sighted yesterday. Around the aft engine section there seems to be loads of coloured tape.

Without a closer look it's only guessing, but I was thinking they could be messages from Hawthorne employees, sending the first FH core on it's way.

It's a bit out there ;D

From here: https://www.reddit.com/r/spacex/comments/65z8yi/falcon_spotting_sighting_in_marana_az_im_pretty/?ref=share&ref_source=link (https://www.reddit.com/r/spacex/comments/65z8yi/falcon_spotting_sighting_in_marana_az_im_pretty/?ref=share&ref_source=link)
Would be cute, but I think some kind of color artifact due to the reflective qualities of the black plastic combined with cheap phone camera.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 04/22/2017 08:55 AM
1023.2 has been taken off the McGregor stand and look who's taken its place, 1033.

(The bit you want to see from Gary Blair's L2 McGregor set:)

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 04/22/2017 01:23 PM
Five days from Hawthorne to on stand at McGregor.
Nice.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Kaputnik on 04/22/2017 10:19 PM
I've never been so excited by the letter 'H' before. Makes it seem suddenly very real.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: sevenperforce on 04/23/2017 04:34 AM
Oh, that's a beautiful sight. Love seeing where the core connections are.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 04/23/2017 01:57 PM
People keep asking for a wider shot (I thought the logo would be the thing people really wanted to see, so rushed that on the turnaround), so here's one from Gary Blair's L2 McGregor collection...well the one that's got as much of the core in it as trees and distance allow. Remember these shots are from a public area outside of the test center (obviously).

Article for this event (the static firing of the FH Center - we're not sure when it's due) and the Static Fire for NROL-76) will be early next week.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: matthewkantar on 04/23/2017 03:08 PM
So I guess the fold up struts that stayed on the center core in the FH CGI video are no longer the plan? It never made sense to me to have the weight of those on the core, better to send em home with the boosters.

Matthew
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 04/23/2017 03:15 PM
So I guess the fold up struts that stayed on the center core in the FH CGI video are no longer the plan? It never made sense to me to have the weight of those on the core, better to send em home with the boosters.

Matthew

That's definitely still the plan. But like fins and legs, they won't be attached until everything is ready for integration at the launch site. No reason to put them on for a static fire.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mme on 04/23/2017 06:49 PM
So I guess the fold up struts that stayed on the center core in the FH CGI video are no longer the plan? It never made sense to me to have the weight of those on the core, better to send em home with the boosters.

Matthew
Nose cone vs. interstage: They cant't fold up on the boosters as there is no place to latch. I don't know if folding down is an option.

The interstage also has a lot more volume for whatever mechanical systems are involved and there may be tradeoffs related to sharing the mechanical systems in the center booster vs. duplicating them on the two side boosters.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 04/24/2017 04:16 PM
So I guess the fold up struts that stayed on the center core in the FH CGI video are no longer the plan? It never made sense to me to have the weight of those on the core, better to send em home with the boosters.

Matthew
Nose cone vs. interstage: They cant't fold up on the boosters as there is no place to latch. I don't know if folding down is an option.

The interstage also has a lot more volume for whatever mechanical systems are involved and there may be tradeoffs related to sharing the mechanical systems in the center booster vs. duplicating them on the two side boosters.

A good reason to have most of the mechanical booster attachment hardware on the center core is aerodynamic and mass balance... Yes, you add some mass to the center core (FH has margin), but it will at least make the side boosters "cleaner" from an aerodynamic point of view. Sure, the center core will have some extra hardware sticking out from the FH trunk, but it will be balanced there as well.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: JasonAW3 on 04/24/2017 04:43 PM
Ok, I'm a bit confused.

      I thought the idea with the first demo flight was to try to recover all three cores.

      Has that changed, or are they simply waiting until they have the cores at the Cape to mount the landing legs?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: tvg98 on 04/24/2017 04:45 PM
Ok, I'm a bit confused.

      I thought the idea with the first demo flight was to try to recover all three cores.

      Has that changed, or are they simply waiting until they have the cores at the Cape to mount the landing legs?

They always attach landing legs, fins, etc at the Cape IIRC. Also, Elon said that the two side boosters will land at LZ-1 and the centre core will land on OCISLY.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 04/25/2017 10:27 AM
Added a round up of the FH milestones at McGregor into the NROL-76 Static Fire article. Thanks again to Gary for his L2 McGregor coverage. Looks like they are close to firing up this center booster. Also another of Nathan's cool L2 renders for the booster landings.

https://www.nasaspaceflight.com/2017/04/spacex-static-fire-tests-spy-sat-rocket-falcon-heavy-core/
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Sesquipedalian on 04/26/2017 02:04 AM
People keep asking for a wider shot (I thought the logo would be the thing people really wanted to see, so rushed that on the turnaround)

I suspect that if you had rushed the wider shot, people would have been clamoring to see the logo.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dcporter on 04/26/2017 04:51 AM
People keep asking for a wider shot (I thought the logo would be the thing people really wanted to see, so rushed that on the turnaround)

I suspect that if you had rushed the wider shot, people would have been clamoring to see the logo.

Confirmed I got very excited for the logo closeup.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: qralt on 05/09/2017 07:53 PM
SpaceX tweeted a video of the center core static fire:

https://twitter.com/SpaceX/status/862017305911320577 (https://twitter.com/SpaceX/status/862017305911320577)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: sanman on 05/09/2017 09:54 PM
Somebody put it up on Youtube, so here it is embedded:

https://www.youtube.com/watch?v=PSAWd-b5uhU
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 05/25/2017 02:52 AM
SpaceX show video of side booster 1023.2 in action at McGregor:

https://twitter.com/SpaceX/status/867568781928701954
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FutureSpaceTourist on 05/25/2017 06:28 AM
SpaceX show video of side booster 1023.2 in action at McGregor:

https://twitter.com/SpaceX/status/867568781928701954

Video attached.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Silmfeanor on 05/25/2017 10:45 AM
Tweet by Elon Musk, confirmation of combined static fire - or perhaps a few static fires:

https://twitter.com/elonmusk/status/867667009839931393 (https://twitter.com/elonmusk/status/867667009839931393)

Quote
Quote
Felix Beuster‏ @FBeuster
Will there be a static fire test of the combined boosters as well, or will Heavy static fires always be separated?

Elon Musk @elonmusk
Replying to @FBeuster

There will be a combined booster static fire. Maybe a few.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: abaddon on 05/25/2017 03:04 PM
Presumably that's just the regular static fire that SpaceX conducts at the pad before all launches, with the "perhaps a few" reflective of this being the maiden launch of a new configuration and (center) core variant?  Last I remember hearing, the McGregor core test capability wasn't sized for Heavy.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: wannamoonbase on 05/25/2017 03:59 PM
Presumably that's just the regular static fire that SpaceX conducts at the pad before all launches, with the "perhaps a few" reflective of this being the maiden launch of a new configuration and (center) core variant?  Last I remember hearing, the McGregor core test capability wasn't sized for Heavy.

Given it's a 3 body vehicle I could see them trying some simulated inputs to verify engine response.  But maybe they can do that with out the engines firing.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Navier–Stokes on 06/08/2017 07:03 PM
Quote from: https://twitter.com/elonmusk/status/872888863504474112
Elon Musk‏Verified account
@elonmusk 

Replying to @JohnnyZenith

All Falcon Heavy cores should be at the Cape in two to three months, so launch should happen a month after that

11:51 AM - 8 Jun 2017
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 06/08/2017 07:16 PM
Quote from: https://twitter.com/elonmusk/status/872888863504474112
Elon Musk‏Verified account
@elonmusk 

Replying to @JohnnyZenith

All Falcon Heavy cores should be at the Cape in two to three months, so launch should happen a month after that

11:51 AM - 8 Jun 2017

For those following along at home, that puts the launch NET Aug 8 to Sept 8, Standard Elon Time; which is roughly November, real world time.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cwr on 06/08/2017 07:26 PM
Quote from: https://twitter.com/elonmusk/status/872888863504474112
Elon Musk‏Verified account
@elonmusk 

Replying to @JohnnyZenith

All Falcon Heavy cores should be at the Cape in two to three months, so launch should happen a month after that

11:51 AM - 8 Jun 2017

For those following along at home, that puts the launch NET Aug 8 to Sept 8, Standard Elon Time; which is roughly November, real world time.

Actually, that sounds like all cores at the Cape between Aug 8 and Sep 8 and the launch between Sep 8 and Oct 8 taking Elon's quote at face value.

Carl
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mn on 06/08/2017 07:51 PM
Quote from: https://twitter.com/elonmusk/status/872888863504474112
Elon Musk‏Verified account
@elonmusk 

Replying to @JohnnyZenith

All Falcon Heavy cores should be at the Cape in two to three months, so launch should happen a month after that

11:51 AM - 8 Jun 2017

This ignores that fact that they are waiting for LC40 to be ready and then another 60 days to make LC39A ready for FH.

Of course the ever optimistic EM will tweet as if the pad is ready, doesn't mean it will be. (neither does this post mean it won't be)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: leetdan on 06/08/2017 07:57 PM
Alternatively, didn't Chris G recently quote SpaceX saying LC-40 was already "active"?  The 60 day window could start after Intelsat and still meet this projection.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 06/08/2017 07:57 PM
Quote from: https://twitter.com/elonmusk/status/872888863504474112
Elon Musk‏Verified account
@elonmusk 

Replying to @JohnnyZenith

All Falcon Heavy cores should be at the Cape in two to three months, so launch should happen a month after that

11:51 AM - 8 Jun 2017

This ignores that fact that they are waiting for LC40 to be ready and then another 60 days to make LC39A ready for FH.

Of course the ever optimistic EM will tweet as if the pad is ready, doesn't mean it will be. (neither does this post mean it won't be)

I highly doubt that Elon is ignoring pad availability, in his tweets or otherwise. I'm sure 3 to 4 months is aggressive, but possible if everything goes to plan.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 06/08/2017 08:02 PM
Alternatively, didn't Chris G recently quote SpaceX saying LC-40 was already "active"?  The 60 day window could start after Intelsat and still meet this projection.

No
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: tvg98 on 06/08/2017 08:25 PM
Alternatively, didn't Chris G recently quote SpaceX saying LC-40 was already "active"?  The 60 day window could start after Intelsat and still meet this projection.

I asked him about that, and it turns out that when they said "active" they actually meant there was a lot of activity at the pad.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mn on 06/08/2017 08:46 PM
Quote from: https://twitter.com/elonmusk/status/872888863504474112
Elon Musk‏Verified account
@elonmusk 

Replying to @JohnnyZenith

All Falcon Heavy cores should be at the Cape in two to three months, so launch should happen a month after that

11:51 AM - 8 Jun 2017

This ignores that fact that they are waiting for LC40 to be ready and then another 60 days to make LC39A ready for FH.

Of course the ever optimistic EM will tweet as if the pad is ready, doesn't mean it will be. (neither does this post mean it won't be)

I highly doubt that Elon is ignoring pad availability, in his tweets or otherwise. I'm sure 3 to 4 months is aggressive, but possible if everything goes to plan.

I don't suspect that he's ignoring it, he just chose not to mention it in his tweet, so I thought it's worth mentioning in case anyone reads his tweet and forgets about that elephant in the room.

Yes it's definitely possible, nobody is denying that, but from reading the LC40 repair thread I got the impression that it's a long shot, (just my impression, I know the official word is it will be 'activated' in august)

See here: https://forum.nasaspaceflight.com/index.php?topic=41060.msg1683397#msg1683397
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Eric Hedman on 06/08/2017 08:50 PM
Hi Res set from Gary Blair (taken from a public area...as always) going into L2 over the coming hours, but this is a big milestone, so passing on at least a preview as "Conehead" is cool.

We believe this is 1023 (formerly the leaning Tower of Thaicom-8). One of the two flight proven S1's that will be with the Falcon Heavy debut.
From the picture it looks like the guy wires are attached to some kind of ring placed over the cone.  Does the center core have attach points for the wires that the side cores don't or are covered up by the cone?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 06/08/2017 11:59 PM
Hi Res set from Gary Blair (taken from a public area...as always) going into L2 over the coming hours, but this is a big milestone, so passing on at least a preview as "Conehead" is cool.

We believe this is 1023 (formerly the leaning Tower of Thaicom-8). One of the two flight proven S1's that will be with the Falcon Heavy debut.
From the picture it looks like the guy wires are attached to some kind of ring placed over the cone.  Does the center core have attach points for the wires that the side cores don't or are covered up by the cone?

The center core (and normal F9s for that matter) have those same guy wires attach to their interstage separation mechanisms. Since the side boosters don't have those, they use that special ring solution.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: wredlich on 06/10/2017 11:35 PM
Hope this isn't a stupid question. I'm planning to drive up to watch the Falcon Heavy launch (and landings) in the fall. Thinking the best view might be from a boat.

There must be rules about how close boats can get to the launch site, but I can't find them. I searched on Google and also in the forums here. So far I can't find anything.

Can anyone point me to such rules?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: BruceM on 06/11/2017 12:54 AM
Hope this isn't a stupid question. I'm planning to drive up to watch the Falcon Heavy launch (and landings) in the fall. Thinking the best view might be from a boat.

There must be rules about how close boats can get to the launch site, but I can't find them. I searched on Google and also in the forums here. So far I can't find anything.

Can anyone point me to such rules?

The restrictions for Cape Canaveral launches are generally temporary and depend on launch date and time among other things.

Temporary restrictions are published as Notices to Mariners (and they also have similar Notices to Airmen).  You can access them for the entire US (along with much other navigation info) at Department of Homeland Security Navigation Center at: https://www.navcen.uscg.gov/?pageName=lnmMain.  For USCG District 7 which includes Cape Canaveral and much more north and south go here:  https://www.navcen.uscg.gov/?pageName=lnmDistrict&region=7.  You can also subscribe and DHS will send them to you as they are issued.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Kabloona on 06/11/2017 01:05 AM
Hope this isn't a stupid question. I'm planning to drive up to watch the Falcon Heavy launch (and landings) in the fall. Thinking the best view might be from a boat.

There must be rules about how close boats can get to the launch site, but I can't find them. I searched on Google and also in the forums here. So far I can't find anything.

Can anyone point me to such rules?

You can see the hazard areas designated as keep-out zones for previous launches on this map made by one of the forum members:

https://www.google.com/maps/d/viewer?mid=1GwvMWuWyokeVZJWqy9nNMH_Pug4&ll=28.60369278482171%2C-80.25713888830194&z=10

Just click the box for the particular mission to see the associated hazard map. You'll see the hazard area varies depending on the launch azimuth, etc. Don't know how the FH hazard areas will compare, but this should give you an idea of minimum allowable approach distances. Since FH carries much more propellant than F9, the FH hazard areas may be larger.

And if you do go, please don't be the "wayward boat" that wanders into the box and causes a launch scrub.  ;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: sanman on 06/11/2017 09:13 AM
Sorry if it's been answered - but what's the payload going to be on this demo mission? Or will it be kept secret until close to the launch date? Will a Dragon capsule be involved in this demo flight?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: KaiFarrimond on 06/11/2017 09:36 AM
Sorry if it's been answered - but what's the payload going to be on this demo mission? Or will it be kept secret until close to the launch date? Will a Dragon capsule be involved in this demo flight?

Gwynne has stated that there won't be a customer for the first FH flight during the LC-39A press conference before the CRS-10 launch. So most likely just a mass simulator.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 06/11/2017 03:32 PM
Just a reminder, payload speculation for the mission can go here:
Falcon Heavy Demo Mission Payload Speculation (https://forum.nasaspaceflight.com/index.php?topic=42801.0)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 07/28/2017 02:49 AM
Tweet from Elon Musk (https://twitter.com/elonmusk/status/890765027032039429):
Quote
Falcon Heavy maiden launch this November https://www.instagram.com/p/BXEkGKlgJDK/
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ThePonjaX on 07/28/2017 04:03 AM
Elon Musk‏
@elonmusk
Side booster rockets return to Cape Canaveral. Center lands on droneship.

https://twitter.com/elonmusk/status/890774088104370176

Another confirmation
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisC on 07/29/2017 02:55 AM
Not really news to us, but another confirmation for the record:

Q to Elon:  who lands first?

A from Elon: Sides run high thrust, center is lower thrust until sides separate & fly back. Center then throttles up, keeps burning & lands on droneship.  ... If we're lucky

https://twitter.com/elonmusk/status/890810308326940672
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: macpacheco on 07/30/2017 12:44 AM
Not really news to us, but another confirmation for the record:

Q to Elon:  who lands first?

A from Elon: Sides run high thrust, center is lower thrust until sides separate & fly back. Center then throttles up, keeps burning & lands on droneship.  ... If we're lucky

https://twitter.com/elonmusk/status/890810308326940672
Side boosters land first.
Center booster flies longer and higher, so when it finishes burning it has more energy => higher apogee => longer flight time
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jpo234 on 08/31/2017 11:31 AM
Cross post from core spotting:
FH side booster in McGregor:
https://m.facebook.com/groups/spacexgroup/permalink/10155786087011318/
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=42977.0;attach=1445474;image)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: spacexfuture on 08/31/2017 01:22 PM
Cross post from core spotting:
FH side booster in McGregor:
https://m.facebook.com/groups/spacexgroup/permalink/10155786087011318/
Beautiful shot.Can't wait to see the demo flight of FH.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: tvg98 on 08/31/2017 01:42 PM
It seems that the preliminary date for the launch is 11/28, but it is subject to change as we all know.

https://www.facebook.com/groups/spacexgroup/permalink/10155786131776318/ (https://www.facebook.com/groups/spacexgroup/permalink/10155786131776318/)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 09/01/2017 03:38 PM
 ;D FCC Application for Launch Vehicle Communications Mission 1346 - Falcon Heavy (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=80036&RequestTimeout=1000)

Quote
This STA is necessary to authorize launch vehicle communications for SpaceX Mission 1346, Complex 39a, Kennedy Space Center. Application includes three sub-orbital first stage boosters, and an orbital second stage. Trajectory data will be provided directly to NTIA, USAF, and NASA. All downrange Earth stations are receive-only. The launch licensing authority is FAA Office of Commercial Space Transportation.

Different frequencies are listed for communication with first stage, second stage, S1-a, and S1-b.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FutureSpaceTourist on 09/02/2017 03:13 AM
Quote
spacex Falcon Heavy’s three first stage cores have all completed testing at our rocket development facility in McGregor, Texas. This side booster previously launched SpaceX’s ninth resupply mission to the @ISS.

https://instagram.com/p/BYheQbWF0dm/ (https://instagram.com/p/BYheQbWF0dm/)

Edit to add video
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: guckyfan on 09/02/2017 06:28 AM
It is on YouTube now

https://www.youtube.com/watch?v=ptJYxCz0WmU
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 09/06/2017 01:06 AM
FCC Permit Application for FH Demo Stage Recovery (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=80084&RequestTimeout=1000)
Quote
This STA uses information from previous application 0739-EX-ST-2017, and covers three experimental first-stage recovery operations following a Falcon 9 launch from Cape Canaveral. This request for authority is limited to two functions: 1) pre-launch checkout test of the TC uplink from an onshore station at CCAFS (less than five minutes in duration) 2) experimental uplink testing from the an onshore station at CCAFS during first-stage descent (less than five minutes in duration) Both operations are pre-coordinated with the launch Range. Launch vehicle flight communications for this mission are covered by a separate STA.

The ASDS is closer to shore for this mission than it is normally stationed for GTO flights:
North  29  0  20    West  77  7  55
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CJ on 09/06/2017 03:21 AM
FCC Permit Application for FH Demo Stage Recovery (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=80084&RequestTimeout=1000)
Quote
This STA uses information from previous application 0739-EX-ST-2017, and covers three experimental first-stage recovery operations following a Falcon 9 launch from Cape Canaveral. This request for authority is limited to two functions: 1) pre-launch checkout test of the TC uplink from an onshore station at CCAFS (less than five minutes in duration) 2) experimental uplink testing from the an onshore station at CCAFS during first-stage descent (less than five minutes in duration) Both operations are pre-coordinated with the launch Range. Launch vehicle flight communications for this mission are covered by a separate STA.

The ASDS is closer to shore for this mission than it is normally stationed for GTO flights:
North  29  0  20    West  77  7  55

Anyone know why the ASDS might be closer to shore? The center core, all things being equal, would have a higher speed at MECO than a F9 ist stage. My SWAG would be far greater margins for this mission (so, a bit of a boostback) or, lofted trajectory.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: stcks on 09/06/2017 03:38 AM
Anyone know why the ASDS might be closer to shore? The center core, all things being equal, would have a higher speed at MECO than a F9 ist stage. My SWAG would be far greater margins for this mission (so, a bit of a boostback) or, lofted trajectory.

The center core should have a higher MECO speed -- but remember it can also have more gas left in the tank which allows for a boostback burn. It could also simply be a much loftier trajectory.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 09/06/2017 04:52 AM
No third pad for core to RTLS (yet), so barge landing.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: oldAtlas_Eguy on 09/07/2017 04:19 PM
Also it could have a max payload size dummy weight 20+mt. The max size for the current standard payload attach fittings. This would put the trajectory as a high LEO or even a GTO but with significant prop remaining in center stage. AF would be interested in the 20+mt real data lofting capabilities. SpaceX wants to know it too.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mheney on 09/07/2017 07:16 PM
There's a line somewhere between "Relevant Discussion" and "No Speculation" - we may be nearing that fuzzy boundary ....
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jfallen on 09/21/2017 11:37 AM
Has there been any movement on the date, since the tentative date of 11/28.  I am going to be in Orlando around then and I will change all plans to go see this.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 09/21/2017 01:58 PM
Has there been any movement on the date, since the tentative date of 11/28.  I am going to be in Orlando around then and I will change all plans to go see this.

We're waiting for confirmation that LC-40 will be a go for KoreaSat; if it is, then 11/28 is still roughly on track since it's 57 days after the last F9 off 39A.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 09/21/2017 02:11 PM
My 2c is that expecting LC-39A to be converted and FH ready to launch in November, especially on that specific date is ludicrous.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jfallen on 09/21/2017 06:05 PM
I would be happy to drive by and see it on the stand, maybe there is still a chance that will happen by 28 Nov.  I imagine they will have it up a few times before lighting up the candle(s).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vaporcobra on 09/21/2017 06:50 PM
I would be happy to drive by and see it on the stand, maybe there is still a chance that will happen by 28 Nov.  I imagine they will have it up a few times before lighting up the candle(s).

I suspect there is a good chance of pad tests by then, even if the launch slips into 2018. But the likelihood of those tests being on the same days you're available are rather tiny 😬
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 09/21/2017 07:23 PM
What to watch for:
1. TE/L tests at LC40
2. Fit checks at both
3. WDR FH
4. F9 launch from LC40
5. Payload for FH ;)
6. FH hotfire(s)
...
Launch!

My "cup of coffee" bet is launch before February, assuming November for 1. Redeemable only in Lompoc after a Falcon/Atlas launch.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 09/21/2017 07:58 PM
What to watch for:
1. TE/L tests at LC40
2. Fit checks at both
3. WDR FH
4. F9 launch from LC40
5. Payload for FH ;)
6. FH hotfire(s)
...
Launch!

My "cup of coffee" bet is launch before February, assuming November for 1. Redeemable only in Lompoc after a Falcon/Atlas launch.
That's a pretty good bet considering what I keep hearing from SpaceX folks. Chances of FH being launched before this year is out are slim. End of November 2017 is a NET. Very much a NET. And will shift several more times.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 09/21/2017 08:04 PM
LC39A still has significant chunks of the RSS as well, and my understanding is that needs to be down before FH can launch.  If the issue is vibration, probably needs to be down before FH static test.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 09/21/2017 08:13 PM
LC39A still has significant chunks of the RSS as well, and my understanding is that needs to be down before FH can launch.  If the issue is vibration, probably needs to be down before FH static test.

It doesn’t have to be, but it probably will be anyways at the rate it’s coming down.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 09/21/2017 09:07 PM
What to watch for:
1. TE/L tests at LC40
2. Fit checks at both
3. WDR FH
4. F9 launch from LC40
5. Payload for FH ;)
6. FH hotfire(s)
...
Launch!

My "cup of coffee" bet is launch before February, assuming November for 1. Redeemable only in Lompoc after a Falcon/Atlas launch.

So you are saying KoreaSat-5A isn't going off 40 in mid October?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 09/22/2017 01:53 AM
There's a line somewhere between "Relevant Discussion" and "No Speculation" - we may be nearing that fuzzy boundary ....

Right
This is rabidly veering into rampant speculation.  All we know about FH is the NET date.  No one has spotted anything relevant at LC-40 or LC-39A.  No official FH announcements. KoreasSat-5A has its own threads.

Mods: Delete this if you wish.  It's admittedly not an update or a discussion of an update, which we haven't had since perhaps gongora's post (http://forum.nasaspaceflight.com/index.php?topic=42705.msg1719795#msg1719795) two weeks ago.
I am as anxious as anyone for this to happen but can we stop posting questions here?
When there is something, it will be posted here.  Asking won't make it happen any sooner.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: leetdan on 09/22/2017 03:27 AM
Is this post considered less-than-definitive? (Re: SES-11 on 39 / Koreasat on 40)

L2 KSC schedule has updated for the first time since Irma:

Oct 2 is the NET.

39A is the pad (last one before FH).

Sept 29 is the Static Fire NET.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nisse on 09/26/2017 07:15 PM
Some FH update here.
https://www.nasaspaceflight.com/2017/09/spacex-realign-manifest-double-launch-salvo/

Quote
Depending on any potential get-ahead work SpaceX can conduct on the 39A TEL inbetween Falcon 9 mission, it is also becoming more unlikely Falcon Heavy will debut in November.

The November target was always notional based on the milestones the new rocket will have to pass before it even reaches launch day.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 09/26/2017 08:06 PM
Quote
Tweet from Stephen Clark (https://twitter.com/StephenClark1/status/912713399083130881)
SpaceX sets Oct. 7 & 9 launch dates for next two Falcon 9 flights from East and West Coasts. Koreasat 5A in late Oct. confirmed from pad 39A

Unless SpaceX can reduce the estimated 60 days minimum rework for 39A, that puts the FH demo NET late December which means likely 2018.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 09/26/2017 08:09 PM
Obviously November is extremely unlikely but we might as well wait a little longer for an updated estimate before we start changing the listed date.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 10/12/2017 01:31 PM
Three SpaceX leaders seem pretty confident that FH will fly in December:

Elon at IAC 2017.

Gwynne at Stanford yesterday:
http://forum.nasaspaceflight.com/index.php?topic=43934.msg1735739#msg1735739

Tom Ochinero, in this article by Peter B. de Selding:
https://www.spaceintelreport.com/spacex-reassures-commercial-satellite-market-falcon-9-wont-soon-scrapped-bfr/
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: abaddon on 10/12/2017 01:39 PM
...and, in related news, there are now zero scheduled launches of Falcon 9 in December.  So it does seem likely they are serious about at least getting Falcon Heavy on the pad at 39-A this calendar year.

Maybe also a sign that SLC-40 isn't going to be ready until next year.  Or maybe they just want all hands on deck for the Falcon Heavy maiden launch campaign.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 10/12/2017 01:48 PM
We really don't know yet if there will be East Coast Falcon 9 launches in December.  Right now I could just as easily see them clearing out November instead of December.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 10/12/2017 01:58 PM
We really don't know yet if there will be East Coast Falcon 9 launches in December.  Right now I could just as easily see them clearing out November instead of December.

If CRS-13 is Nov 28 and it bumps HispaSat back, I could easily seen both dropping into December. But both are tentatively expected to go from 40, so 39A could go into full FH demo mode once KoreaSat launches in a few weeks.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: octavo on 10/13/2017 02:17 PM


...and, in related news, there are now zero scheduled launches of Falcon 9 in December.  So it does seem likely they are serious about at least getting Falcon Heavy on the pad at 39-A this calendar year.

Maybe also a sign that SLC-40 isn't going to be ready until next year.  Or maybe they just want all hands on deck for the Falcon Heavy maiden launch campaign.

Crossposting:

Yes. According official FCC application (https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=80640&RequestTimeout=1000) issued last week (3th Oct) SpaceX plans launch CRS-13 mission from Complex 40.

They're serious about late Nov for slc - 40
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Michael Baylor on 10/15/2017 01:54 AM
A look at progress on the new landing zone over the last month.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vaporcobra on 10/15/2017 02:23 AM
A look at progress on the new landing zone over the last month.

Worth a repost.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 10/15/2017 04:23 AM
The last two images make a nice sequence.
It indeed looks like SpaceX started with the 200' square.
They poured the arc (or "lune") farthest from the road before the image above.
Then they poured the "side arcs" before the image above that one.
If we have the dates from the EXIFs we could guess if they have the last piece in place already.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vaporcobra on 10/15/2017 05:45 AM
The last two images make a nice sequence.
It indeed looks like SpaceX started with the 200' square.
They poured the arc (or "lune") farthest from the road before the image above.
Then they poured the "side arcs" before the image above that one.
If we have the dates from the EXIFs we could guess if they have the last piece in place already.

I wish Instagram preserved original EXIF data :( It was posted on 9 October and I expect it was taken a couple hours or days before at most.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ronsmytheiii on 10/20/2017 07:29 PM
core 1025 headed to the cape!

https://imgur.com/gallery/RJfT5
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Herb Schaltegger on 10/20/2017 09:32 PM
core 1025 headed to the cape!

https://imgur.com/gallery/RJfT5

That's exciting an all, but weren't we told weeks ago (longer maybe?) that all three FH cores were already there? 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 10/20/2017 10:10 PM
core 1025 headed to the cape!

https://imgur.com/gallery/RJfT5

That's exciting an all, but weren't we told weeks ago (longer maybe?) that all three FH cores were already there?

Yes, but this one hadn’t gone back to Texas yet for testing. Now they’re all at the Cape and they’ve all been tested.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: shuttlefan on 10/21/2017 02:43 PM
core 1025 headed to the cape!

https://imgur.com/gallery/RJfT5

That's exciting an all, but weren't we told weeks ago (longer maybe?) that all three FH cores were already there?

Yes, but this one hadn’t gone back to Texas yet for testing. Now they’re all at the Cape and they’ve all been tested.

Are they all in the Pad 39-A Horizontal Integration Facility?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: crandles57 on 10/22/2017 10:04 PM
http://spaceflight101.com/calendar/

has Dec 30 for Falcon Heavy Demo.
But it also says NET December and perhaps the new format is forcing them to put a date in, so it probably doesn't mean anything.

(Similar for HispaSat shown as Dec 17 but again says NET December.)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mdeep on 10/23/2017 02:12 AM
http://spaceflight101.com/calendar/

has Dec 30 for Falcon Heavy Demo.
But it also says NET December and perhaps the new format is forcing them to put a date in, so it probably doesn't mean anything.

(Similar for HispaSat shown as Dec 17 but again says NET December.)

It looks like their software isn't setup to handle vague NET dates.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Shanuson on 10/26/2017 06:31 AM
X-posting from KoreaSat Updates:
TEL is now back in the HIF. There are also reports that all three FH cores are in there as well, I'm sure it's nice and cozy!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 10/30/2017 12:18 PM
From the SpaceX photos on the KoreaSat thread. Was it public that the outside east and west holddowns were installed? I remember seeing that the outside north side ones were installed, but can't find that picture now.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 10/30/2017 12:55 PM
From the SpaceX photos on the KoreaSat thread. Was it public that the outside east and west holddowns were installed? I remember seeing that the outside north side ones were installed, but can't find that picture now.
The previous image that supposedly showed the outside west hold-down installed in fact showed a shadow: https://forum.nasaspaceflight.com/index.php?topic=41015.msg1735121#msg1735121 (https://forum.nasaspaceflight.com/index.php?topic=41015.msg1735121#msg1735121)

The new Koreasat image however clearly shows that the east and west outside hold-downs are now installed.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 10/30/2017 03:11 PM
Hopefully the webcast will show the south side holddowns installed as well :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cppetrie on 10/30/2017 06:26 PM
All three FH cores confirmed as being in the hanger during processing of today’s KoreaSat mission.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ronsmytheiii on 10/30/2017 07:13 PM
From Koreasat webcast, FH cores to the left and right
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ronsmytheiii on 10/30/2017 07:14 PM
And the Launch mount modifications with new TSMs
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cppetrie on 10/30/2017 07:20 PM
Is this one of the south side hold downs or light effect?
(https://uploads.tapatalk-cdn.com/20171030/752d87ed7bbf6e127ce327ce1018463a.jpg)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 10/30/2017 07:51 PM
Is this one of the south side hold downs or light effect?
(https://uploads.tapatalk-cdn.com/20171030/752d87ed7bbf6e127ce327ce1018463a.jpg)

It is a south side holddown, but it's the center one used for F9.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cppetrie on 10/30/2017 08:07 PM
Is this one of the south side hold downs or light effect?
(https://uploads.tapatalk-cdn.com/20171030/752d87ed7bbf6e127ce327ce1018463a.jpg)

It is a south side holddown, but it's the center one used for F9.
Can’t be. It isn’t inline with the booster on the TEL. Center south would be hidden by the erector arm in that pic and not visible.

Edit: I think see what you’re suggesting. That what I circled is the side panel of the center south hold down. Not totally convinced, but maybe.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: zubenelgenubi on 11/01/2017 03:57 PM
Operational question:
If the launch campaign for Falcon Heavy Demo is such that the vehicle is ready for launch during the "holidays," would it be better for the launch campaigners' managers to delay scheduling the launch until after New Year's Day?
(That is, for a launch that does not need to meet a celestial mechanics launch window or a national security imperative.)

To specify:
Are there substantial additional staff costs that would arise from attempting a launch from KSC between Saturday, December 23 and Monday, January 1, inclusive?

Or morale costs?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 11/01/2017 04:10 PM
Status Update, including L2 info - by Chris Gebhardt:
https://www.nasaspaceflight.com/2017/11/spacex-aims-december-launch-falcon-heavy/
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 11/01/2017 04:12 PM
Is this one of the south side hold downs or light effect?
(https://uploads.tapatalk-cdn.com/20171030/752d87ed7bbf6e127ce327ce1018463a.jpg)

It is a south side holddown, but it's the center one used for F9.
Can’t be. It isn’t inline with the booster on the TEL. Center south would be hidden by the erector arm in that pic and not visible.

Edit: I think see what you’re suggesting. That what I circled is the side panel of the center south hold down. Not totally convinced, but maybe.
All South Side TSM's have been installed. That is what is circled. Only the South side Hold Downs and North side TSM's await installation which should be done before ZUMA launches. Then its all of the Plumbing, Data, and wiring for the reaction frame and the final kitting out of the TEL that has to be done for FH-01 to fly.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 11/01/2017 09:29 PM
Thanks for the great article Chris G with Nathan's eye candy. Looks like we might be in for a great Christmas present! 8)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: robbak on 11/01/2017 11:37 PM
One question being bandied about on the reddit - the 2-engines-at-a-time start procedure - is that two engines per stack (so, 14 different start delays), or 2 engines per core, or 5 start delays? The 2-per stack might be smoother overall, but it does lead to off-center loads on each stack that are avoided if they light 2 per core at a time.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 11/01/2017 11:44 PM
One question being bandied about on the reddit - the 2-engines-at-a-time start procedure - is that two engines per stack (so, 14 different start delays), or 2 engines per core, or 5 start delays? The 2-per stack might be smoother overall, but it does lead to off-center loads on each stack that are avoided if they light 2 per core at a time.
AFAIK it is 2 per core.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Norm38 on 11/02/2017 02:35 AM
What does that mean?  They start 9 at a time now right?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Tomness on 11/02/2017 02:46 AM
Status Update, including L2 info - by Chris Gebhardt:
https://www.nasaspaceflight.com/2017/11/spacex-aims-december-launch-falcon-heavy/
Awesome Chris G and Chris B... so close... like to have shout out to all the men and women who are working tirelessly to make this FH come true...is going be awesome!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rsnellenberger on 11/02/2017 04:36 AM
Nice article. 

The info about the staggered startup was interesting, but I would have liked to see some mention or discussion of any testing that SpaceX has done to support that kind of startup.  Before AMOS-6, I could have imagined them trying it for the first time on 39A during the static test - it’s hard to believe that they’d try that now.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 11/02/2017 06:26 AM
One question being bandied about on the reddit - the 2-engines-at-a-time start procedure - is that two engines per stack (so, 14 different start delays), or 2 engines per core, or 5 start delays? The 2-per stack might be smoother overall, but it does lead to off-center loads on each stack that are avoided if they light 2 per core at a time.
AFAIK it is 2 per core.

To expand on this a bit, how certain are we that they're not already employing a staggered start for single stick F9 cores?

They definitely are employing a staggered shutdown as can be seen in all the footage plus I always got the impression that there is more than 1 TEA/TEB flash during pad ignition, but several rapid ones instead, at least in post v1.0 vehicles.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Star One on 11/02/2017 10:56 AM
The site is famous as we are sourced in this PM article about the launch.

http://www.popularmechanics.com/space/rockets/news/a28872/spacex-first-launch-falcon-heavy/
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mn on 11/02/2017 01:34 PM
Thanks Chris G for the excellent article. (as usual)

a: Where can I find more info on the issue of thrust torque, I don't remember seeing it and it doesn't come up in searches.

b: Can we assume the range is available any time in late December once FH is ready and SpaceX requests it? or are there also specific windows they need to squeeze into?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: abaddon on 11/02/2017 01:53 PM
b: Can we assume the range is available any time in late December once FH is ready and SpaceX requests it? or are there also specific windows they need to squeeze into?
Don't know about holiday schedule for the range, but nobody else has any scheduled launches in December from Canaveral/Kennedy.  So they should be relatively free to fit it in as they can.

The next scheduled flight from Florida for a non-SpaceX launcher is an Atlas V from SLC-41 in the middle of January.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: wannamoonbase on 11/02/2017 02:29 PM
The site is famous as we are sourced in this PM article about the launch.

http://www.popularmechanics.com/space/rockets/news/a28872/spacex-first-launch-falcon-heavy/

No doubt there are some rocket nerd PopSci folks lurking on this site.  Why wouldn't they, this is the best source of info.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: intrepidpursuit on 11/02/2017 02:40 PM
Nice article. 

The info about the staggered startup was interesting, but I would have liked to see some mention or discussion of any testing that SpaceX has done to support that kind of startup.  Before AMOS-6, I could have imagined them trying it for the first time on 39A during the static test - it’s hard to believe that they’d try that now.

I'm sure they've tested it on the stand at McGregor. If I understand the plumbing on F9 it can currently only start the engines in two groups, 3 used for boost back and the remaining 6, so they wouldn't be able to do the staggered startup on a standard static fire. They are probably building the granularity into Block 5 for uniformity, but I'd guess this is one of the modifications they made in Hawthorne to the flight proven boosters.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 11/02/2017 03:15 PM
Intrepidpursuit: I think you're confusing *restart* with *start*.  Only three of the F9's engines are equipped with on-board TEA/TEB reservoirs and plumbing necessary for in-flight restarts.  The other engines get their TEA/TEB plumbed from ground supplies pre-liftoff.

The 1/3 engine restrictions in-flight probably have nothing to do with "staggered start", which happens on the ground.

That said, it's reasonable to assume that staggered start would require GSE changes or maybe even additional valves on-vehicle.  I'm inclined to agree with you that staggered start (including GSE-side changes) would have been tested at McGregor when the FH cores went through there.  But the necessary replumbing might not have been done on the LC39A TEL yet.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 11/02/2017 03:49 PM
What does that mean?  They start 9 at a time now right?
F9 can start all 9 at once but for FH to allow SLC-39A and SLC-4E to avoid a domino effect of pad damage they are to be started differently to preserve the pad's flame trench (the results of the acoustic, vibration, and thrust impingement damage estimate models and concluded reasoning were discussed in detail in multiple previous threads). It is also my understanding as I remember reading about in a thread ages ago that liftoff will be at slighlty reduced thrust until clear of the pad and FSS before switching to full thrust mode.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Star One on 11/02/2017 03:56 PM
Was reading in a current book how demanding each Saturn V launch was on the launch infrastructure. How likely is this launch to damage the infrastructure, I mean a launcher this powerful hasn’t been launched in sometime, beyond the DH, and it’s not possible to perfectly model an event like this beforehand?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: wannamoonbase on 11/02/2017 04:01 PM
Nice article. 

The info about the staggered startup was interesting, but I would have liked to see some mention or discussion of any testing that SpaceX has done to support that kind of startup.  Before AMOS-6, I could have imagined them trying it for the first time on 39A during the static test - it’s hard to believe that they’d try that now.

I'm sure they've tested it on the stand at McGregor. If I understand the plumbing on F9 it can currently only start the engines in groups two groups, 3 used for boost back and the remaining 6, so they wouldn't be able to do the staggered startup on a standard static fire. They are probably building the granularity into Block 5 for uniformity, but I'd guess this is one of the modifications they made in Hawthorne to the flight proven boosters.

Machines work on a different time scale than humans.  The start up maybe staggered but appear almost simultaneous to us humans. 

The side booster staging event is going to be the money event of this launch.  We haven't seen a staging event like that since shuttle.

Likely with this first flight they can have extra time (fractions of a second perhaps) to be safe and those times can be trimmed with experience in successive flights.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meberbs on 11/02/2017 04:04 PM
What does that mean?  They start 9 at a time now right?
F9 can start all 9 at once but for FH to allow SLC-39A and SLC-4E to avoid a domino effect of pad damage they are to be started differently to preserve the pad's flame trench (the results of the acoustic, vibration, and thrust impingement damage estimate models and concluded reasoning were discussed in detail in multiple previous threads). It is also my understanding as I remember reading about in a thread ages ago that liftoff will be at slighlty reduced thrust until clear of the pad and FSS before switching to full thrust mode.
The article says that it is because of a thrust torque problem damaging the ocotwebs, not because of impingement damage to the flame trench. This makes sense due to the different load paths on the Falcon Heavy. There will always be a small difference in engine start time whether intentional or not. If one side booster started all engines slightly before the other one, this would create a massive torque. Starting 2 engines at a time with a pause in between reduces the maximum unbalanced torque.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rpapo on 11/02/2017 04:06 PM
The side booster staging event is going to be the money event of this launch.  We haven't seen a staging event like that since shuttle.
Just how different is it from what happens on Delta 4 Heavy launches?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 11/02/2017 04:11 PM
The side booster staging event is going to be the money event of this launch.  We haven't seen a staging event like that since shuttle.
Just how different is it from what happens on Delta 4 Heavy launches?

It's different than the Space Shuttle and Delta IV Heavy because the Falcon Heavy side cores are NOT equipped with separation rockets, or in KSP terms "sepratrons."

Cold-gas thrusters are too weak to help with the separation process.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rpapo on 11/02/2017 04:17 PM
The side booster staging event is going to be the money event of this launch.  We haven't seen a staging event like that since shuttle.
Just how different is it from what happens on Delta 4 Heavy launches?

It's different than the Space Shuttle and Delta IV Heavy because the Falcon Heavy side cores are NOT equipped with separation rockets, or in KSP terms "sepratrons."

Cold-gas thrusters are too weak to help with the separation process.
I was only wondering about the "since the shuttle" remark.  Delta 4 Heavy has flown since then.  I agree that this will be quite a challenge for what SpaceX prefers: mechanical separators.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 11/02/2017 04:52 PM
The only crucial events that SpaceX is worried about are the initial liftoff followed by tower clearance, Max-Q, and side core separation.

After that, it's treated like a normal Falcon 9 mission with the addition of two simultaneous landings of the side cores.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mme on 11/02/2017 04:57 PM
The only crucial events that SpaceX is worried about are the initial liftoff followed by tower clearance, Max-Q, and side core separation.

After that, it's treated like a normal Falcon 9 mission with the addition of two simultaneous landings of the side cores.
That's a fairly long list to say "only."  It's basically "everything up to second stage separation." :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 11/02/2017 04:58 PM
The only crucial events that SpaceX is worried about are the initial liftoff followed by tower clearance, Max-Q, and side core separation.

After that, it's treated like a normal Falcon 9 mission with the addition of two simultaneous landings of the side cores.

Sounded like control authority during booster return was also a question mark since the nose cone doesn't have a good flow separation point.

Do we know if all the Heavy boosters will have Ti grid fins?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 11/02/2017 05:00 PM
I remember Elon Musk saying that he's worried about a possible pad explosion, so if Falcon Heavy clears the tower, he's relieved for the time being because then the vehicle has to go through Max-Q, which could potentially rip everything apart if there's one or more defects.

And about the side core separation, well, there's no separation rockets, so we'll hope for the best.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 11/02/2017 05:01 PM
The only crucial events that SpaceX is worried about are the initial liftoff followed by tower clearance, Max-Q, and side core separation.

After that, it's treated like a normal Falcon 9 mission with the addition of two simultaneous landings of the side cores.

Sounded like control authority during booster return was also a question mark since the nose cone doesn't have a good flow separation point.

Do we know if all the Heavy boosters will have Ti grid fins?

The side boosters must have them for the control authority problems you mentioned, and it seems likely that the center core will have them due to higher than usual reentry velocities.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisGebhardt on 11/02/2017 05:22 PM
b: Can we assume the range is available any time in late December once FH is ready and SpaceX requests it? or are there also specific windows they need to squeeze into?
Don't know about holiday schedule for the range, but nobody else has any scheduled launches in December from Canaveral/Kennedy.  So they should be relatively free to fit it in as they can.

The next scheduled flight from Florida for a non-SpaceX launcher is an Atlas V from SLC-41 in the middle of January.

The only U.S federal holiday in December is Christmas Day, and holidays are not "absolutely no work under any circumstance" days.  Launches have and will occur on holidays.

As for other launches on the range, Hispasat is out there in late-December as well, though that one has no confirmed target date yet.  Hispasat is expendable, so it doesn't need the ASDS.  And since all the Falcon family rockets have AFTS and are both Falcons, we won't need range reconfigurations.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 11/02/2017 06:38 PM
What does that mean?  They start 9 at a time now right?
F9 can start all 9 at once but for FH to allow SLC-39A and SLC-4E to avoid a domino effect of pad damage they are to be started differently to preserve the pad's flame trench (the results of the acoustic, vibration, and thrust impingement damage estimate models and concluded reasoning were discussed in detail in multiple previous threads). It is also my understanding as I remember reading about in a thread ages ago that liftoff will be at slighlty reduced thrust until clear of the pad and FSS before switching to full thrust mode.
The article says that it is because of a thrust torque problem damaging the ocotwebs, not because of impingement damage to the flame trench. This makes sense due to the different load paths on the Falcon Heavy. There will always be a small difference in engine start time whether intentional or not. If one side booster started all engines slightly before the other one, this would create a massive torque. Starting 2 engines at a time with a pause in between reduces the maximum unbalanced torque.
I was actually talking about to separate topics and didn't make that clear enough it seems.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 11/02/2017 06:41 PM
I remember Elon Musk saying that he's worried about a possible pad explosion, so if Falcon Heavy clears the tower, he's relieved for the time being because then the vehicle has to go through Max-Q, which could potentially rip everything apart if there's one or more defects.

And about the side core separation, well, there's no separation rockets, so we'll hope for the best.
AFAIK, Cold gas thrusters on the top of the side boosters will be fired at separation to impart separation and arcing away from the core boosters velocity vector.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 11/02/2017 06:46 PM
I remember Elon Musk saying that he's worried about a possible pad explosion, so if Falcon Heavy clears the tower, he's relieved for the time being because then the vehicle has to go through Max-Q, which could potentially rip everything apart if there's one or more defects.

And about the side core separation, well, there's no separation rockets, so we'll hope for the best.
AFAIK, Cold gas thrusters on the top of the side boosters will be fired at separation to impart separation and arcing away from the core boosters velocity vector.

And the boosters' center engines will fire for a little bit after separation for high control
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 11/02/2017 06:48 PM
The side booster staging event is going to be the money event of this launch.  We haven't seen a staging event like that since shuttle.
Just how different is it from what happens on Delta 4 Heavy launches?

It's different than the Space Shuttle and Delta IV Heavy because the Falcon Heavy side cores are NOT equipped with separation rockets, or in KSP terms "sepratrons."

Cold-gas thrusters are too weak to help with the separation process.
not all Cold gas thrusters are weak. Sort of hot staging the boosters is what i have seen elsewhere.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Mike Jones on 11/02/2017 06:52 PM
Any clue about the payload for this Falcon Heavy maiden flight ?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: spacenut on 11/02/2017 06:53 PM
I would love to see them launch a Dragon capsule around the moon and back on the first launch. 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 11/02/2017 06:59 PM
Any clue about the payload for this Falcon Heavy maiden flight ?

Nothing at all definitive.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 11/02/2017 07:02 PM
I would love to see them launch a Dragon capsule around the moon and back on the first launch. 
To much internal risk as Dragon v2 still hasn't flown to LEO yet and SpaceX's BEO communications network not yet ready worldwide to handle such a mission.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 11/02/2017 07:04 PM
Can grid fins help with separation? Or is the aerodynamic regime too severe, or does using them 'in reverse' just not work? (turning them 180 at speed might not be the best approach.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: spacenut on 11/02/2017 07:07 PM
Since this is a demo, I was thinking about re-using a Dragon I capsule they use to supply ISS.  Just as a Demo, not a lot of money to spend. 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 11/02/2017 07:10 PM
Payload speculation/wishes don't go here, use the FH Demo Payload Speculation (https://forum.nasaspaceflight.com/index.php?topic=42801.0) thread.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 11/02/2017 07:28 PM
Can grid fins help with separation? Or is the aerodynamic regime too severe, or does using them 'in reverse' just not work? (turning them 180 at speed might not be the best approach.
Given the "floppiness" of gridfin deployments, I wouldn't expect them to work well with deploying against large forces in the opposite direction.  And the middle of a separation event isn't high on my list of times I'd like unpredictable force transients somewhat randomly applied to the nose of my vehicle.  But, I'm not at all sure that booster separation will be taking place low enough in the atmosphere for this to be an issue.  And, if it isn't low enough to be a factor nor will it be low enough to help/interfere with the separation either.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: georgegassaway on 11/03/2017 03:57 AM
Would not want to have the nose section of the outer boosters to do the main work of separation.  imagine if SpaceX used just explosive bolts and suddenly the three were flying free in parallel, and only forces on the noses pushed the boosters outward, nothing else. The rear of the boosters would pivot (pinch) inwards and hit the center core (due to pivoting about their CG’s). 

So for one, they need some rear attachment system on the Octawebs that will either allow the outer boosters to pivot outwards, or for the rear attachments to actively push the rear of the boosters outwards during separation (but at less of an acceleration rate than the noses are pushed outwards, to produce an outwards yaw rotation rate).  While the forward attachments will actively push the noses outwards pneumatically.

Once separated with some outwards velocity vector, and rotating (yawing) outwards a few degrees, whatever small amount of aerodynamic forces  (thin air) should help to push them outwards even more, crude aerodynamic lift despite not having the grid fins deployed yet. With the center core accelerating away, the outer boosters will be left behind quickly, and those boosters will be moving apart from each other, so the RCS (if not already used in the separation process) can work to pivot the boosters around quickly enough to begin the Boostback maneuver.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 11/03/2017 04:09 AM
What would happen if the center engines or (engine trios) were left on but kept pointed counter to the axis of the center stage, up to some angular limit? 
Suppose the acceleration of the nearly empty boosters is close to that of the center core.
Given a "modest" push outward, the boosters would "fall" outward. 
There would be some reaction towards the center core at the base, as their CGs would be low, but not at the pivot.
However, this could be counteracted by pivoting the engine(s) to thrust slightly outward.   
When the angular limit was hit, the thrust would push the boosters out.
Perhaps as george suggested this could continue into the boostback maneuver.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Steven Pietrobon on 11/03/2017 07:38 AM
The Russians solved the booster separation problem years ago with the R-7 (now Soyuz) without the need of solid separation motors. I believe the R-7 vents its LOX tank to help tip over the booster. Perhaps SpaceX is doing the same.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 11/03/2017 08:15 AM
I believe the R-7 vents its LOX tank to help tip over the booster. Perhaps SpaceX is doing the same.

R-7 strapons arent required to reignite seconds later for RTLS and I'm not sure venting the tank would be such a good idea.
2) F9 LOX vents are actually directed downwards, not sideways so they wouldn't do much.

Also, not that it matters that much, the placement of the vents vs core attachment would make the strapons separate a-la Titan IV SRMs and unlike Delta IV Heavy (sideways).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 11/03/2017 08:28 AM
I believe the R-7 vents its LOX tank to help tip over the booster. Perhaps SpaceX is doing the same.

R-7 strapons arent required to reignite seconds later for RTLS and I'm not sure venting the tank would be such a good idea.
2) F9 LOX vents are actually directed downwards, not sideways so they wouldn't do much.

Also, not that it matters that much, the placement of the vents vs core attachment would make the strapons separate a-la Titan IV SRMs and unlike Delta IV Heavy (sideways).

Has anyone here considered a solution to the separation event along the lines of Ariane 3 and Ariane 4?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vanoord on 11/03/2017 08:31 AM
Since this is a demo, I was thinking about re-using a Dragon I capsule they use to supply ISS.  Just as a Demo, not a lot of money to spend.

99.99% this flight will have a fairing - they need to fly the vehicle with three times (IIRC) to qualify it for government contracts.

What's inside the fairing is the question, but (i) it's not going to be a Dragon; and (ii) in that case it won't be coming back in one piece.

The words 'school' and 'bus' seem to have featured - but from my way of thinking, I doubt their structure is designed for the sort of G-loadings that orbital launch is going to put on them  (  ::) ) and it would be a lot easier just to use a mass simulator. Not to mention that if it's been Elon's idea, then he's busy trying to get the Tesla Model 3 into mass production, so humorous payloads are going to be much less of a priority.

My own thought was that if they were looking for a payload to carry inside a Dragon capsule, then some sort of commemorative metal discs (call them coins, medallions, whatever) which could be used as ballast, then recovered and  sold - I reckon there are plenty of people who would have been happy to pay for a commemorative coin that had been orbitally flown.

To be honest, if it's got a payload fairing on, a mass simulator inside and a modified S2 with heat tiles to see how long it can survive re-entry; and if the whole thing launches without failure, then it'll be a very good outcome.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cuddihy on 11/03/2017 10:10 AM

Has anyone here considered a solution to the separation event along the lines of Ariane 3 and Ariane 4?

What are you suggesting?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 11/03/2017 11:20 AM

Has anyone here considered a solution to the separation event along the lines of Ariane 3 and Ariane 4?

What are you suggesting?
Sorry. I keep forgetting that not everyone here is familiar with the earlier versions of the Ariane launch system.

What I am referring to is spring-assisted separation event.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 11/03/2017 12:04 PM
So for one, they need some rear attachment system on the Octawebs that will either allow the outer boosters to pivot outwards, or for the rear attachments to actively push the rear of the boosters outwards during separation (but at less of an acceleration rate than the noses are pushed outwards, to produce an outwards yaw rotation rate).  While the forward attachments will actively push the noses outwards pneumatically.

Both the nosecones and the octawebs have pneumatic pusher mechanisms, and the octawebs also have a beefy connection point at the hold-down lugs. Whether or not that pivots before full separation is to be seen though.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: intrepidpursuit on 11/03/2017 02:28 PM
We have a thread devoted to the topic of booster separation on Falcon Heavy that perhaps needs a bump now. This post more or less summarized what we know thanks to old_sellsward.

https://forum.nasaspaceflight.com/index.php?topic=43255.msg1698889#msg1698889
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: georgegassaway on 11/03/2017 02:39 PM

Both the nosecones and the octawebs have pneumatic pusher mechanisms, and the octawebs also have a beefy connection point at the hold-down lugs. Whether or not that pivots before full separation is to be seen though.

OK, thanks.  Given similar pneumatic pushers on the Octawebs, it may be that those would not provide as much of a push as the ones on the nose.  Therefore causing an outwards  yaw as well, not just a parallel outwards separation. Would not require RCS to begin the yaw  alone.

Will be VERY interesting to see onboard video(s) from the boosters as the separation time nears. Perhaps splitscreen with a camera on the center core, showing both outer boosters as they begin to separate, and a camera on one of the  boosters which would not only show separation, but as it yaws outwards, the other booster being in view for awhile.

Could also be interesting if they added a new camera location on the boosters, looking towards the core, to show a view like this from shuttle SRB's.  Not for PR purposes, they'd need to justify it for engineering study purposes (this is a very high-risk phase so they'd want to document this very well to see how well it goes, or worst-case try to figure what went wrong)

(http://www.maniacworld.com/booster-rocket-free-fall.jpg)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 11/16/2017 09:06 AM
Quote
Shotwell: a few more launches for SpaceX this year including “hopefully, knock on wood” first Falcon Heavy.

https://twitter.com/jeff_foust/status/931082821002846208 (https://twitter.com/jeff_foust/status/931082821002846208)


Note: less than two months ago no less than 3 SpaceX leaders were certain FH would launch in December this year (https://forum.nasaspaceflight.com/index.php?topic=42705.msg1735902#msg1735902). Now one of them is knocking on wood and hopes it will launch in December this year.


Slippery little bastards them heavies...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: 2megs on 11/16/2017 11:30 AM
Slippery little bastards them heavies...

I don't necessarily read it as a slip. Once they have it vertical on the pad, the timeline to launch may be driven as much by analyzing and resolving unknowns as by the work they already anticipate. Shotwell knows that; she's not Musk and tends to not over-promise.

So coming from her, I interpret a statement like that to mean the rocket will be vertical on the pad early enough that a launch in December can happen if no significant issues are identified in the WDR and static fire. It's in the realm of possibility, but not certainty, and with a new configuration that's all anyone can credibly promise.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: whatever11235 on 11/16/2017 11:41 AM
I agree with 2megs. Shotwell is much more conservative on schedule, maybee even too much. Anti-Musk.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 11/16/2017 11:53 AM
I think they make a good leadership pair.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 11/16/2017 11:58 AM
I think they make a good leadership pair.
When the history of how we finally became an interstellar civilization is written, I hope she gets all the credit she so richly deserves, because they make a GREAT team.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 11/16/2017 01:20 PM
I agree with 2megs. Shotwell is much more conservative on schedule, maybee even too much. Anti-Musk.

Not by a long shot. Take some time and compare Gwynne-provided estimates from the past 5 years with Elon-provided estimates from the past 5 years. Both are generally over-optimistic. The only difference is that Gwynne is slightly less over-optimistic compared to Elon. Both are anything but conservative on schedule.

Gwynne may be the SpaceX President and COO, but it is Elon (as CEO and CTO) who is setting the pace. Gwynne's only option is to follow.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 11/16/2017 01:47 PM
... follow .... Or quit.

And let's hope she doesn't do that. We're a bit off topic, but it would be a serious blow to lose her. She's the adult in the room :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 11/16/2017 02:54 PM
... follow .... Or quit.

And let's hope she doesn't do that. We're a bit off topic, but it would be a serious blow to lose her. She's the adult in the room :)

Frequently true. 
Making payroll for 7,000 employees is not to be taken lightly -- not that either of them do -- but his pragmatic approach to rapidly design/test/iterate is likely countered by her equally pragmatic financial approach, 'how-we-gonna-pay-for-that'?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 11/16/2017 09:41 PM
I agree with 2megs. Shotwell is much more conservative on schedule, maybee even too much. Anti-Musk.
I think they make a good leadership pair.

I agree with cscott but think its more Counter-Musk than Anti-Musk

At the risk of being an irrelevant discussion, I really hope this launch doesn't slip more than a week into the new year, because that would give me the chance to go see it.  A double triple sonic boom!

According to Google Maps, it's 9.63 km from the end of the pier at Jetty Park to where LZ-1, the first landing pad is, and ~9.69 km to the second pad as seen in the photo in this post. (http://forum.nasaspaceflight.com/index.php?topic=36513.msg1740232#msg1740232)  <100 meters is <0.30 seconds delay, which is is close to my impression of the delay between the first sonic boom and the latter pair of booms from the returning first stage.  It would be like fireworks as they overlap, if they land simultaneously. 
Does that mean SpaceX has to delay one so it doesn't interact with the shock wave from the other?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rpapo on 11/16/2017 09:59 PM
Does that mean SpaceX has to delay one so it doesn't interact with the shock wave from the other?
Actually, from the point of view of sonic booms, I would expect that having both rockets come down side by side, separated by a few hundred meters, would probably be best.  The interaction between the sonic booms would happen well above and away from the descending rockets.  The only dicey point would be the transonic regime, when the shock wave front is nearly planar.

EDIT: Thinking about this, I hope the tracking cameras can catch that area in their view.  It may be interesting.  How often do we see two large objects generating shock waves only a few hundred meters apart? 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: georgegassaway on 11/17/2017 03:32 AM
There is some likelihood that the two side boosters will not do a perfect mirror / synchronized separation pitch-around (& yaw-around) such that one might end up a little bit farther downrange than the other, and not “catch up” with the other one.  But let’s assume perfect synchronization so they’d be side by side downrange-wise, eventually landing at the same moment….. but far apart laterally for the sake of the comments below.

They would not necessarily be coming in a few hundred feet apart during the re-entry burn or going transsonic.  No need to come in at the same distance apart as the individual landing pads are. They could be programmed to intentionally be say a mile or two apart. Let’s say 2 miles apart, one a ballistic course a mile north of LZ-1 and one a mile south of LZ-1, if not more.  Somewhere between the re-entry burn and going transsonic, when the grid fins are aerodynamically steering each booster to “glide” to extend the ballistic path (which would otherwise impact offshore), they would use the same steering capability to begin to do a minor dog-leg for each to converge towards LZ-1 (South one landing at the original pad and the North one at the new pad).  So in that case, if shock waves were a concern, they could do it that way to keep them pretty far apart for a lot of the way down.

Will be interesting, after the flight, if there actually is a ground plot of the incoming booster paths, to show if they do something like that.  Last thing I would expect is they’d be  as close as 1200 feet apart horizontally (whatever the distance between the two landing pads are) during the re-entry burn or when they go subsonic (though by the time they go subsonic, they’d not be nearly as far apart as likely during re-entry, they'd be converging).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 11/17/2017 01:26 PM
How often do we see two large objects generating shock waves only a few hundred meters apart?

The military flies large supersonic jets fairly close to each other quite often.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rpapo on 11/17/2017 01:41 PM
How often do we see two large objects generating shock waves only a few hundred meters apart?

The military flies large supersonic jets fairly close to each other quite often.
I know that.  The Falcon is much larger.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FinalFrontier on 11/17/2017 02:02 PM
Fair question here, due to Zuma slip what will be the effect if any on FH still flying before the year ends?

And/or if there are further slips due to this fairing issue.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Mike_1179 on 11/17/2017 02:08 PM
How often do we see two large objects generating shock waves only a few hundred meters apart?

The military flies large supersonic jets fairly close to each other quite often.
I know that.  The Falcon is much larger.

The B1-B flies supersonic and is about 45m long. It's a bit larger than a Falcon 9 first stage. While I'm not going to say that flying a rocket backwards is no different from flying a plane, it's not such a rare thing.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: douglas100 on 11/17/2017 08:41 PM
Fair question here, due to Zuma slip what will be the effect if any on FH still flying before the year ends?

And/or if there are further slips due to this fairing issue.

Stands to reason that the longer Zuma stays on the pad the less time there will be to get the TEL converted and get FH off before the end of the year. It's quite possible that FH will slip into the New Year.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Herb Schaltegger on 11/17/2017 09:24 PM
How often do we see two large objects generating shock waves only a few hundred meters apart?

The military flies large supersonic jets fairly close to each other quite often.
I know that.  The Falcon is much larger.

The B1-B flies supersonic and is about 45m long. It's a bit larger than a Falcon 9 first stage. While I'm not going to say that flying a rocket backwards is no different from flying a plane, it's not such a rare thing.

The B-1A was designed to fly supersonically as a matter of course. The B-1B lost the variable geometry intakes that allowed for optimal supersonic cruise, which lowered its maximum speed at altitude quite a bit. Further, B model gained the dorsal ridge of ECM equipment and additional software/sensors for low level, high-subsonic penetration into hostile airspace. Supersonic flight is no longer the airframe's forte, and I daresay B-1Bs rarely break the sound barrier operationally at all, to the extent they ever did. More importantly for this discussion, B-1's of neither model were ever intended to fly supersonically within a few hundred yards of one another.

That said, B-1 generally is a typical supersonic aircraft design of the era - long, sleek and properly pointed at the end that creates the main shockwave, with swept wings and tail that also optimize their secondary shocks. By stark contrast, a falling F9 is a blunt body with vastly different aerodynamics. Presumable SpaceX has done plenty of CFD modeling of potential shock interactions and have no concerns. But we (as outside observers) should not handwave away the discussion by reference to conventional supersonic airframe design.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jakusb on 11/19/2017 10:55 AM
Fair question here, due to Zuma slip what will be the effect if any on FH still flying before the year ends?

And/or if there are further slips due to this fairing issue.

Stands to reason that the longer Zuma stays on the pad the less time there will be to get the TEL converted and get FH off before the end of the year. It's quite possible that FH will slip into the New Year.

I would expect the other option being them to do last modification ASAP, if the fairing would have to be build again...
Then a serious delay due to the fairing-rebuild could expedite the FH Demo pre-launch activities.
And maybe move Zuma to SLC-40..? After CSR-13 of course.
They should have a general idea of impact by now. All depends on it being a fix/modification or total rebuild of fairings.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rebel44 on 11/20/2017 06:12 PM
If Zuma really is delayed until at least December (which is currently being reported) can SpaceX move its launch to SLC-40 and start working on LC 39A to prepare it for Falcon Heavy launch?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: speedevil on 11/20/2017 06:25 PM
If Zuma really is delayed until at least December (which is currently being reported) can SpaceX move its launch to SLC-40 and start working on LC 39A to prepare it for Falcon Heavy launch?

Related also to if FH-demo will use a fairing.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisGebhardt on 11/20/2017 07:37 PM
If Zuma really is delayed until at least December (which is currently being reported) can SpaceX move its launch to SLC-40 and start working on LC 39A to prepare it for Falcon Heavy launch?

Related also to if FH-demo will use a fairing.

Bingo.  FH has a fairing, too.  But to the SLC-40 question, why?  What would be the need to move Zuma to SLC-40?

CRS-13 is getting ready to go from SLC-40, and with a crew rotation period coming up, ISS traffic is a factor in having CRS-13 in early-December (not mid- to late-December if that can be avoided). 

And there is no need to move Zuma to SLC-40 just so 39A work can proceed for a maiden voyage of a rocket that doesn't have to launch by the end of the December.  If FH goes in January, that is perfectly all right.

Why completely disrupt paying customers' launch schedules by taking a perfectly active pad offline to prepare for a mission that isn't for a customer, isn't for profit, and doesn't have a "we need it launched by this date" aspect to its mission?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: zubenelgenubi on 11/20/2017 09:39 PM
If Zuma really is delayed until at least December (which is currently being reported) can SpaceX move its launch to SLC-40 and start working on LC 39A to prepare it for Falcon Heavy launch?

Related also to if FH-demo will use a fairing.

Seeking confirmation: Is the FH PLF to be the same "make/model" as currently used on F9?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CuddlyRocket on 11/21/2017 04:01 AM
If Zuma really is delayed until at least December (which is currently being reported) can SpaceX move its launch to SLC-40 and start working on LC 39A to prepare it for Falcon Heavy launch?

Related also to if FH-demo will use a fairing.

Seeking confirmation: Is the FH PLF to be the same "make/model" as currently used on F9?

Does it matter? The demo mission is to demonstrate the launcher, not the fairing! If the fairing fails to open or opens improperly does that invalidate the test of the launcher which will have already passed through launch, maxQ, MECO, staging and second stage ignition? At worst you'll demonstrate an already suspected fault in the fairing. (Although the second stage might not complete its full firing sequence, it's a standard second stage - already flown on multiple missions.) Of course, you'll lose whatever's inside the fairing, but that might only be a mass simulator!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 11/21/2017 04:31 AM
Yes it matters. A fairing failure would stop all launches with fairings during the failure investigation.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: penguin44 on 11/21/2017 06:53 AM
If Zuma really is delayed until at least December (which is currently being reported) can SpaceX move its launch to SLC-40 and start working on LC 39A to prepare it for Falcon Heavy launch?

Related also to if FH-demo will use a fairing.

Seeking confirmation: Is the FH PLF to be the same "make/model" as currently used on F9?

Does it matter? The demo mission is to demonstrate the launcher, not the fairing! If the fairing fails to open or opens improperly does that invalidate the test of the launcher which will have already passed through launch, maxQ, MECO, staging and second stage ignition? At worst you'll demonstrate an already suspected fault in the fairing. (Although the second stage might not complete its full firing sequence, it's a standard second stage - already flown on multiple missions.) Of course, you'll lose whatever's inside the fairing, but that might only be a mass simulator!

Also you forgot that the fairing could fail any time after ignition. Could come apart before maxQ
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mn on 11/21/2017 02:37 PM
Yes it matters. A fairing failure would stop all launches with fairings during the failure investigation.

Seems that is already the case, without a failure.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Michael Baylor on 11/28/2017 08:25 PM
Numerous reports and confirmed by SpaceX: Falcon Heavy NET early 2018.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FutureSpaceTourist on 11/28/2017 08:52 PM
Bit more detail:

Quote
SpaceX confirms Aviation Week report that the Falcon Heavy’s debut test flight is now expected in early 2018, a few weeks after a hold-down static fire test at KSC in December.

https://twitter.com/stephenclark1/status/935619345182543872
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisGebhardt on 11/28/2017 11:27 PM
Bit more detail:

Quote
SpaceX confirms Aviation Week report that the Falcon Heavy’s debut test flight is now expected in early 2018, a few weeks after a hold-down static fire test at KSC in December.

https://twitter.com/stephenclark1/status/935619345182543872

In other words, it slipped by about 1 week.  And it's only "news" because it crossed a year boundary in that week. :D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: georgegassaway on 11/29/2017 05:13 AM
In other words, it slipped by about 1 week.  And it's only "news" because it crossed a year boundary in that week. :D

How did you extract "early 2018" to mean first week of January???  Not even January, but first week of January?

Heck, I take it to mean Q1 of 2018. Which is what I predicted during Q1 of this year (hoping I'd be wrong, but considering everything related to FH announced scheduling for years, that seemed more likely than July 2017 did at the time).

I'd love for it to be the first week of January. But fool me once, fool me twice, fool me 27 or so times.... eventually a pattern emerges.  :)   and  :(
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: hamerad on 11/29/2017 06:06 AM
In other words, it slipped by about 1 week.  And it's only "news" because it crossed a year boundary in that week. :D

How did you extract "early 2018" to mean first week of January???  Not even January, but first week of January?

Heck, I take it to mean Q1 of 2018. Which is what I predicted during Q1 of this year (hoping I'd be wrong, but considering everything related to FH announced scheduling for years, that seemed more likely than July 2017 did at the time).

I'd love for it to be the first week of January. But fool me once, fool me twice, fool me 27 or so times.... eventually a pattern emerges.  :)   and  :(
Maybe the part that says bold mine
Bit more detail:

Quote
SpaceX confirms Aviation Week report that the Falcon Heavy’s debut test flight is now expected in early 2018, a few weeks after a hold-down static fire test at KSC in December.
[/b]

https://twitter.com/stephenclark1/status/935619345182543872
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 11/29/2017 06:09 AM
Bit more detail:

Quote
SpaceX confirms Aviation Week report that the Falcon Heavy’s debut test flight is now expected in early 2018, a few weeks after a hold-down static fire test at KSC in December.

https://twitter.com/stephenclark1/status/935619345182543872 (https://twitter.com/stephenclark1/status/935619345182543872)

In other words, it slipped by about 1 week.  And it's only "news" because it crossed a year boundary in that week. :D

You should have seen the static I was sent privately when I reported info (https://forum.nasaspaceflight.com/index.php?topic=41015.msg1726990#msg1726990) (coming from SpaceX-ers no less), in september this year, that FH was fully expected to slip into 2018.

But in the end those SpaceX sources turned out to be correct.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: georgegassaway on 11/30/2017 12:01 AM

Maybe the part that says bold mine
Quote
SpaceX confirms Aviation Week report that the Falcon Heavy’s debut test flight is now expected in early 2018, a few weeks after a hold-down static fire test at KSC in December.

So, for your interpretation that  the launch to have just slipped one week into the first week of January,  you expect all hold down static firing tests  to be completed in the first week or two of December?

That’s the only way that “a few weeks” between then and the launch could be first week of January (if everything else worked out OK).

I’m willing to say “I was wrong” if it flies  before the 2nd week of January. Heck, I want to see it fly soon too.

Somewhere, there still may be someone expecting FH to launch tomorrow, because Elon said November.   :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: guckyfan on 11/30/2017 07:37 AM

You should have seen the static I was sent privately when I reported info (https://forum.nasaspaceflight.com/index.php?topic=41015.msg1726990#msg1726990) (coming from SpaceX-ers no less), in september this year, that FH was fully expected to slip into 2018.

But in the end those SpaceX sources turned out to be correct.

Actually no, they did not. Without the Zuma problems they might well have made it this year. Sources saying months ago that it can not happen this year were missing important developments like working in parallel on LC-40 and LC-39A.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Pete on 11/30/2017 09:55 AM

You should have seen the static I was sent privately when I reported info (https://forum.nasaspaceflight.com/index.php?topic=41015.msg1726990#msg1726990) (coming from SpaceX-ers no less), in september this year, that FH was fully expected to slip into 2018.

But in the end those SpaceX sources turned out to be correct.

Actually no, they did not. Without the Zuma problems they might well have made it this year. Sources saying months ago that it can not happen this year were missing important developments like working in parallel on LC-40 and LC-39A.

And yet, despite all your denials, the launch has still been moved to January. So YES they were correct.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: guckyfan on 11/30/2017 11:58 AM
And yet, despite all your denials, the launch has still been moved to January. So YES they were correct.

Not relevant. Their reasons were wrong.

Edit: Or to formulate it differently, their statement that FH would not fly this year was based on wrong assumptions. So invalid even if in the end FH now does not fly this year.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 11/30/2017 12:26 PM
And yet, despite all your denials, the launch has still been moved to January. So YES they were correct.

Not relevant. Their reasons were wrong.

Edit: Or to formulate it differently, their statement that FH would not fly this year was based on wrong assumptions. So invalid even if in the end FH now does not fly this year.

You have no idea what their reasons were.

And FH slipping to 2018 isn’t based purely on the Zuma situation anyways, it’s a complicated scenario with no one factor causing it.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 11/30/2017 01:43 PM
The blame and I-told-you-so game is boring the rest of us.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: JamesH65 on 11/30/2017 01:52 PM

You should have seen the static I was sent privately when I reported info (https://forum.nasaspaceflight.com/index.php?topic=41015.msg1726990#msg1726990) (coming from SpaceX-ers no less), in september this year, that FH was fully expected to slip into 2018.

But in the end those SpaceX sources turned out to be correct.

Actually no, they did not. Without the Zuma problems they might well have made it this year. Sources saying months ago that it can not happen this year were missing important developments like working in parallel on LC-40 and LC-39A.

Even myself, a world class optimist, expected it to be delayed to 2018. And I don't even work at SpaceX.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 12/01/2017 12:45 AM
Any time SpaceX schedules something right at the end of the calendar year like that, I pretty much automatically assume it will roll over into the next year.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FutureSpaceTourist on 12/01/2017 01:15 AM
Quote
Falcon Heavy's 3 cores are shown in the lower left corner at Aerospace Corp's launch-control room display, awaiting test fire <span class="emoji-outer emoji-sizer"><span class="emoji-inner" style="background: url(chrome-extension://immhpnclomdloikkpcefncmfgjbkojmh/emoji-data/sheet_apple_32.png);background-position:55.99294947121034% 10.047003525264394%;background-size:5418.75% 5418.75%" data-codepoints="1f525"></span></span>

https://twitter.com/sandymazza/status/936407173772353536



--

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: su27k on 12/01/2017 02:29 AM
Quote
Falcon Heavy's 3 cores are shown in the lower left corner at Aerospace Corp's launch-control room display, awaiting test fire 🔥

So why would Aerospace Corporation have access to SpaceX's hangar cameras? And why do they have a launch control room anyway, I thought AC just do analysis for the Air Force?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/01/2017 02:32 AM
I love the 39A pad shot cams, I could stare at live versions of those all day, just watching them work on the TEL...

Reminds me of the camera shot of Pad 0A at Wallops that they have inside the visitor center, if any of you have been there.

Looks like this, but zoomed in slightly.

(https://www.universetoday.com/wp-content/uploads/2013/07/IMG_7072a_Wallops_Ken-Kremer.jpg)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 12/01/2017 03:12 AM
Quote
Falcon Heavy's 3 cores are shown in the lower left corner at Aerospace Corp's launch-control room display, awaiting test fire

https://twitter.com/sandymazza/status/936407173772353536

Edit: added cropped & slightly rotated version. Note TEL at pad too.

Given that the launch trajectory on the right is showing Oct. 15th which was the date of the NROL-52 launch (Atlas V 421 out of CCAFS) there's a good chance that this pic isn't recent.  Though strangely, it also shows an Atlas V still in the barn.  So, I'm not sure what's up with that.  It can't be a current live shot because the next Atlas launch from SLC-41 (SBIRS-GEO 4 on Jan. 19th) is an Atlas V 411 and this one has at least 2 SRBs.  Weird.  Maybe the trajectory is a simulation prior to the launch?  Or just not live pictures of the Atlas?

Oops.  Actually Delta IV, not Atlas V in the corner.  Thanks Thorny. That's embarrassing.

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Thorny on 12/01/2017 03:19 AM
Though strangely, it also shows an Atlas V still in the barn.  So, I'm not sure what's up with that.  It can't be a current live shot because the next Atlas launch from SLC-41 (SBIRS-GEO 4 on Jan. 19th) is an Atlas V 411 and this one has at least 2 SRBs.  Weird. 

Isn't that a Delta IV?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: hernick on 12/01/2017 03:20 AM
Today is the 334th day of the year 2017. The on-screen display is reading 334 17:57:09; it seems to me like that photo was taken today.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Michael Baylor on 12/01/2017 03:22 AM
Though strangely, it also shows an Atlas V still in the barn.  So, I'm not sure what's up with that.  It can't be a current live shot because the next Atlas launch from SLC-41 (SBIRS-GEO 4 on Jan. 19th) is an Atlas V 411 and this one has at least 2 SRBs.  Weird. 

Isn't that a Delta IV?
It's the Delta IV at Vandenberg for NROL 47 on December 13. Now lets shut up before the off-topic police arrive on the scene.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 12/01/2017 03:45 AM
Quote
Falcon Heavy's 3 cores are shown in the lower left corner at Aerospace Corp's launch-control room display, awaiting test fire

So why would Aerospace Corporation have access to SpaceX's hangar cameras? And why do they have a launch control room anyway, I thought AC just do analysis for the Air Force?

The Aerospace Corp does a lot of mission support for a lot of customers, they might be contracted for Zuma or the FH Demo or both.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 12/01/2017 06:33 AM
Quote
Falcon Heavy's 3 cores are shown in the lower left corner at Aerospace Corp's launch-control room display, awaiting test fire 🔥

So why would Aerospace Corporation have access to SpaceX's hangar cameras? And why do they have a launch control room anyway, I thought AC just do analysis for the Air Force?
They are involved in both USAF and NASA cert efforts of SpaceX launch vehicles. Access to the cameras in the SpaceX processing facilities is part of the Insight/Oversight agreement between government agencies and SpaceX.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 12/01/2017 10:48 AM
The screen next to the three booster view is more recognisable as a view of the Heavy. It's pretty clear that there is three aft ends of the boosters together with legs visible there.

Second stage mating in progress.  Right hand picture.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Swoopert on 12/01/2017 10:54 AM
The screen next to the three booster view is more recognisable as a view of the Heavy. It's pretty clear that there is three aft ends of the boosters together with legs visible there.
Actually I believe that the left-hand camera is showing L-R - Zuma (with transporter ring above the legs), FH-side, FH-core, and the other FH-side is off camera to right as you can see reversed in the right-hand camera view...the FH-side booster is being supported by the crane and is slightly shifted compared to the core, I'm assuming for better access to the interstage for 2nd stage integration?

I believe that the left-hand camera is mounted on the crane jib? which is visible above the other FH-side booster in the right-hand camera view with the red drop downs in its foreground also visible and matching up, which explains why only the other 3 boosters are visible.

Edited to clarify to which screenshot I was referring and camera positioning.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/01/2017 01:34 PM
The outboard boosters both have nosecones. Not Zuma.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ATPTourFan on 12/01/2017 02:33 PM
The outboard boosters both have nosecones. Not Zuma.

Photos are shot from opposite sides. There's a S1/S2 integrated F9 alongside the 3 FH cores. When photo angle is reversed to see the aft engine ends, you can see the end of the integrated F9, then side FH and center FH and the other side FH booster is too close and "under" the frame.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 12/01/2017 07:12 PM
Quote
Falcon Heavy's 3 cores are shown in the lower left corner at Aerospace Corp's launch-control room display, awaiting test fire <span class="emoji-outer emoji-sizer"><span class="emoji-inner" style="background: url(chrome-extension://immhpnclomdloikkpcefncmfgjbkojmh/emoji-data/sheet_apple_32.png);background-position:55.99294947121034% 10.047003525264394%;background-size:5418.75% 5418.75%" data-codepoints="1f525"></span></span>

https://twitter.com/sandymazza/status/936407173772353536



--



Sandy has deleted her tweet and SpaceX has requested the main areas where SpaceX is discussed to remove attachments/screenshots of the tweet, so we have too.

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Tomness on 12/01/2017 08:55 PM
--


Sandy has deleted her tweet and SpaceX has requested the main areas where SpaceX is discussed to remove attachments/screenshots of the tweet, so we have too.
Understandable, first rule of the NRO club you do not talk about the NRO club..
Pulling a Yoda, "unlearn what you have you have learned"
When they launch this naughty rocket (FH)... people going to go nuts..
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 12/02/2017 05:15 PM
Moved all the Roadster posts into the standalone thread:
https://forum.nasaspaceflight.com/index.php?topic=42801.0
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: butterwaffle on 12/03/2017 01:49 AM
Does anyone have an idea on what the inclination will be near launch for a Mars trip? Will that impact what viewing location would be better? Will Playalinda and/or the causeway be open for the FH launch?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jim on 12/03/2017 01:59 AM
Does anyone have an idea on what the inclination will be near launch for a Mars trip? Will that impact what viewing location would be better? Will Playalinda and/or the causeway be open for the FH launch?

No impact
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jpo234 on 12/03/2017 08:26 AM
Not just a Roadster post, information about the orbit:

http://www.syfy.com/syfywire/elon-musk-on-the-roadster-to-mars

Quote
No, it’s not going to Mars. It’s going near Mars. He said it’ll be placed in “a precessing Earth-Mars elliptical orbit around the sun.” What he means by this is what’s sometimes called a Hohmann transfer orbit, an orbit around the Sun that takes it as close to the Sun as Earth and as far out as Mars. This is a low-energy orbit; that is, it takes the least amount of energy to put something in this orbit from Earth. That makes sense for a first flight.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: SmallKing on 12/03/2017 10:34 AM
Elon tweeted that the destination was deep space
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: MarekCyzio on 12/03/2017 12:31 PM
Does anyone have an idea on what the inclination will be near launch for a Mars trip? Will that impact what viewing location would be better? Will Playalinda and/or the causeway be open for the FH launch?

Expect Playalinda to be closed.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Michael Baylor on 12/03/2017 04:31 PM
Does anyone have an idea on what the inclination will be near launch for a Mars trip? Will that impact what viewing location would be better? Will Playalinda and/or the causeway be open for the FH launch?

Expect Playalinda to be closed.
Why? I thought it was approved to be open for all launches.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: tleski on 12/03/2017 04:47 PM
Does anyone have an idea on what the inclination will be near launch for a Mars trip? Will that impact what viewing location would be better? Will Playalinda and/or the causeway be open for the FH launch?

Expect Playalinda to be closed.
Why? I thought it was approved to be open for all launches.
My recommendation is to call the park headquarters before the launch to confirm if the beach is open. This is what I did when visiting the area last summer.
See the website below:
https://www.nps.gov/cana/planyourvisit/hours.htm
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dodo on 12/03/2017 06:11 PM
Layman question: in such a Hohmann transfer orbit (and when not terminated by Mars orbit insertion), is there a risk of the trajectory intersecting Earth at some point in the future? (Presumably not right on the first orbit, since Earth is no longer there, but at some common multiple of the Earth's and payload's orbital period, I imagine.)

Edit: s/Hoffman/Hohmann/
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Kaputnik on 12/03/2017 06:29 PM
Layman question: in such a Hohmann transfer orbit (and when not terminated by Mars orbit insertion), is there a risk of the trajectory intersecting Earth at some point in the future? (Presumably not right on the first orbit, since Earth is no longer there, but at some common multiple of the Earth's and payload's orbital period, I imagine.)

Edit: s/Hoffman/Hohmann/

Yes, but it's also possible to be in an orbit that has an exact resonance with Earth and will not intersect Earth's position.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dodo on 12/03/2017 06:34 PM
Layman question: in such a Hohmann transfer orbit (and when not terminated by Mars orbit insertion), is there a risk of the trajectory intersecting Earth at some point in the future? (Presumably not right on the first orbit, since Earth is no longer there, but at some common multiple of the Earth's and payload's orbital period, I imagine.)

Edit: s/Hoffman/Hohmann/

Yes, but it's also possible to be in an orbit that has an exact resonance with Earth and will not intersect Earth's position.

Follow up: are Mars and Earth in resonant orbits, like Jupiter's inner moons? (I don't think so.) If not, I reckon it may not be possible to compute an orbit that avoids BOTH Earth and Mars.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: kevin-rf on 12/03/2017 06:54 PM

Follow up: are Mars and Earth in resonant orbits, like Jupiter's inner moons? (I don't think so.) If not, I reckon it may not be possible to compute an orbit that avoids BOTH Earth and Mars.

Think 3d, if you change the inclination slightly, it is possible to always have an apogee that is above, or below Mar's orbital plane, forever missing. Though I do think the perigee will always intersection with Earth's plane.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: shooter6947 on 12/03/2017 07:01 PM

Follow up: are Mars and Earth in resonant orbits, like Jupiter's inner moons? (I don't think so.) If not, I reckon it may not be possible to compute an orbit that avoids BOTH Earth and Mars.

No; none of the planets in the Solar System are resonant, though we've found resonant exoplanets.  Pluto is 3:2 resonant with Neptune, but, you know, not really a planet. 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ictogan on 12/03/2017 08:42 PM
Layman question: in such a Hohmann transfer orbit (and when not terminated by Mars orbit insertion), is there a risk of the trajectory intersecting Earth at some point in the future? (Presumably not right on the first orbit, since Earth is no longer there, but at some common multiple of the Earth's and payload's orbital period, I imagine.)

Edit: s/Hoffman/Hohmann/

Yes, but it's also possible to be in an orbit that has an exact resonance with Earth and will not intersect Earth's position.
Under the assumption that there will be no system that is able to do any burns after the roadster has left earth's vincinity, wouldn't it be impossible for it to enter such a resonant non-earth-intersecting orbit?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dodo on 12/03/2017 08:55 PM
Under the assumption that there will be no system that is able to do any burns after the roadster has left earth's vincinity, wouldn't it be impossible for it to enter such a resonant non-earth-intersecting orbit?

Why? The final orbit is determined by the delta-V at Earth's departure, plus whatever change results from the close shave to Mars. (I imagine the shave won't be that close, if they have no way of fine-tuning the approach.)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ictogan on 12/03/2017 08:58 PM
Under the assumption that there will be no system that is able to do any burns after the roadster has left earth's vincinity, wouldn't it be impossible for it to enter such a resonant non-earth-intersecting orbit?

Why? The final orbit is determined by the delta-V at Earth's departure, plus whatever change results from the close shave to Mars. (I imagine the shave won't be that close, if they have no way of fine-tuning the approach.)
A resonant orbit would mean that it has the same position relative to earth every x years. If it starts at earth and goes into an orbit that has a resonance with earth, it should return to earth after x years.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/03/2017 09:19 PM
Any C3 escape launch will have its orbit intersect with Earth's orbit, because the US+payload are now in a new orbit that only differs by the net effective delta-v vector of the launch itself. (The exceptions to this would be in exceeding heliocentric escape velocity (never returns) or cancels enough of Earths orbital velocity to never intersect the orbit.)

Lets say you're not in the two above cases - what means could you use to avoid such intersection? Another propulsive maneuver out of the gravitational influence of the Earth (in significance) could change a parameter to never fall into the influence/intersection, or a gravitational interaction with a third body for like effect. One could also inject in/through/near a gravitational equipotential and cause a chaotic orbit that would never have a stable interaction with the Earth/Moon system that would coincide with an orbital intersection. You could never prove a solution that would ever cause it to return.

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rsdavis9 on 12/04/2017 01:57 PM
venus and earth are in a 3:2 resonance?

EDIT: a resonance of its rotation with the earths orbit.

https://en.wikipedia.org/wiki/Tidal_locking

Quote
Venus's 583.92-day interval between successive close approaches to Earth is equal to 5.001444 Venusian solar days, making approximately the same face visible from Earth at each close approach. Whether this relationship arose by chance or is the result of some kind of tidal locking with Earth is unknown.[14]
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/04/2017 02:14 PM
venus and earth are in a 3:2 resonance?

I looked it up and couldn't find anything on it.

EDIT: They're in a near 8:13 resonance according to Wikipedia.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: llanitedave on 12/05/2017 05:12 AM

Follow up: are Mars and Earth in resonant orbits, like Jupiter's inner moons? (I don't think so.) If not, I reckon it may not be possible to compute an orbit that avoids BOTH Earth and Mars.

Think 3d, if you change the inclination slightly, it is possible to always have an apogee that is above, or below Mar's orbital plane, forever missing. Though I do think the perigee will always intersection with Earth's plane.

Only in the absence of future perturbations.  But its orbit will be subject to at least semi-close encounters with Earth and Mars, and with small but frequent perturbations by Jupiter.  I suspect that over the ages, both perigee and apogee will change.  Maybe drastically.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Bynaus on 12/05/2017 06:03 AM
The typical dynamical lifetime of near Earth asteroids is on the order of a few 10 million years. Within that typical time frame, they either collide with the sun, a planet, or might even be ejected from the inner solar system. This of course applies for the roadster too. There is no orbit where it would be fully protected from destabilization, although some orbits are more stable than others. But since the roadster's orbit will always pass close to the Earth, its biggest risk for orbit destabilization will always be an Earth encounter.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Pete on 12/05/2017 06:33 AM
The typical dynamical lifetime of near Earth asteroids is on the order of a few 10 million years. Within that typical time frame, they either collide with the sun, a planet, or might even be ejected from the inner solar system.
Collide with the sun? From a earth-mars orbit?
Where would the object get the needed 20-25km/s of speed change?
.
Also for ejecting from the inner solar system, you would need to find some 10km/s++ from somewhere. That is possible with a series of gravity slings, but *ludicrously* unlikely.
Lifting the apoapse out of the inner solar system is a lot easier, and even that will take multiple fortuitous gravity encounters, most likely with earth.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dodo on 12/05/2017 06:08 PM
Lifting the apoapse out of the inner solar system is a lot easier, and even that will take multiple fortuitous gravity encounters, most likely with earth.

I am trying to imagine, without much success, where periapsis and apoapsis would be, if (I believe) the Earth-Mars trip is only a short arc of a much longer heliocentric orbit.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 12/05/2017 06:54 PM
Lifting the apoapse out of the inner solar system is a lot easier, and even that will take multiple fortuitous gravity encounters, most likely with earth.

I am trying to imagine, without much success, where periapsis and apoapsis would be, if (I believe) the Earth-Mars trip is only a short arc of a much longer heliocentric orbit.

If the trajectory is a Hohmann transfer, the periapsis is at Earth's orbit, and apoapsis is at Mars' orbit.

Faster transfers raise the apoapsis, but periapsis always lies on Earth's orbit. This is true even if the transfer is inclined out of the ecliptic - gravity always take you back the same place, at least until the orbit is perturbed.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Steve D on 12/05/2017 07:05 PM
A guy from work was telling me the boosters would not be recovered on this flight. I thought they were. Has there been a change of plans due to the Mars orbit they want to go to?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 12/05/2017 07:06 PM
A guy from work was telling me the boosters would not be recovered on this flight. I thought they were. Has there been a change of plans due to the Mars orbit they want to go to?

An early version of an article mistakenly said that and was later changed.  I haven't seen any other information saying the boosters will be expended.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 12/05/2017 07:14 PM
A guy from work was telling me the boosters would not be recovered on this flight. I thought they were. Has there been a change of plans due to the Mars orbit they want to go to?

An early version of an article mistakenly said that and was later changed.  I haven't seen any other information saying the boosters will be expended.
They will be recovered (that is: SpaceX will attempt recovery). Sources at KSC have spotted all three cores in the HIF sporting landing legs. SpaceX doesn't put landing legs on cores they intend to expend.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Steve D on 12/05/2017 07:25 PM
A guy from work was telling me the boosters would not be recovered on this flight. I thought they were. Has there been a change of plans due to the Mars orbit they want to go to?

An early version of an article mistakenly said that and was later changed.  I haven't seen any other information saying the boosters will be expended.
They will be recovered (that is: SpaceX will attempt recovery). Sources at KSC have spotted all three cores in the HIF sporting landing legs. SpaceX doesn't put landing legs on cores they intend to expend.


Cool. That didn't sound right to me but we also thought this was just an LEO flight. Going for escape velocity I wasn't sure if they would have to expend the boosters or not.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 12/05/2017 08:23 PM
A guy from work was telling me the boosters would not be recovered on this flight. I thought they were. Has there been a change of plans due to the Mars orbit they want to go to?

An early version of an article mistakenly said that and was later changed.  I haven't seen any other information saying the boosters will be expended.
They will be recovered (that is: SpaceX will attempt recovery). Sources at KSC have spotted all three cores in the HIF sporting landing legs. SpaceX doesn't put landing legs on cores they intend to expend.


Cool. That didn't sound right to me but we also thought this was just an LEO flight. Going for escape velocity I wasn't sure if they would have to expend the boosters or not.

An expendable Falcon Heavy could launch about 13 Roadsters to Mars transfer. No problems going with recovery for this light payload.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Eagandale4114 on 12/06/2017 04:25 AM
Quote from: /u/TheRealWhiskers
If this isn't already known, the TEL has been on the pad for at least two days now in the 'post-launch' configuration. They have the two F9 side hold-down clamps removed and sitting at the east edge of the pad complete with the white supporting structure beneath them partially covered in soot. Of course, in my infinite wisdom, I drove 1,500 miles and forgot to bring the cable to transfer pictures from my DSLR.

Quote from: /u/TheRealWhiskers
It's a bit difficult to tell through all of the other pad structure getting in the way, but it looks like all 6 hold downs are now in place. I'll admit I'm not 100% sure what to look for as in TSM's so I can't help much there.
I also forgot to mention, this morning and into the early afternoon the south HIF door was raised about 15 feet for a fork lift to move in and out. I snapped some pictures through the moving bus window but my camera didn't do a stellar job. It may get a lot better with some editing, but you can clearly see the top ends of the FH center core, a side booster with nose cone, and another F9 core.
Edit: FH S2 may have been present but blocked from view by a large white crate sitting in the doorway. It was definitely not attached to the center core.

No pictures yet, as he forgot his camera to computer cable but we should get some soon.

Reddit link (https://www.reddit.com/r/spacex/comments/7hjp03/falcon_heavy_demo_launch_campaign_thread/dqtucdr/?st=jaum1ofy&sh=5554093b)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/06/2017 04:38 AM
All 6? I assume he knows that there will be *8* (eight) hold downs for FH.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: robert_d on 12/06/2017 09:04 AM
How close to first roll-out then? Any chance for the 'money shot' with Falcon 9 on the pad at the same time as the Falcon Heavy? Too far apart? Are the pads far enough apart that they could risk the Heavy on the pad at the lift off of the Falcon 9?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: codav on 12/06/2017 09:31 AM
All 6? I assume he knows that there will be *8* (eight) hold downs for FH.
Yes, eight hold-down clamps (three for each side booster, two for the center core) and two compression bridges. The latter don't hold the boosters down, they just provide structural support for the center core.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/06/2017 09:48 AM
With triple the cores and therefore way more densified LOX required, do we know if a launch (or static fire) can be held without scrubbing to rechill the LOX?

Or enough for a recycle - as in, is there in the very least six cores, plus two second stage’s worth of densified LOX available at LC-39A?

Edited for semantics
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 12/06/2017 12:47 PM
A guy from work was telling me the boosters would not be recovered on this flight. I thought they were. Has there been a change of plans due to the Mars orbit they want to go to?

An early version of an article mistakenly said that and was later changed.  I haven't seen any other information saying the boosters will be expended.
They will be recovered (that is: SpaceX will attempt recovery). Sources at KSC have spotted all three cores in the HIF sporting landing legs. SpaceX doesn't put landing legs on cores they intend to expend.


Cool. That didn't sound right to me but we also thought this was just an LEO flight. Going for escape velocity I wasn't sure if they would have to expend the boosters or not.

An expendable Falcon Heavy could launch about 13 Roadsters to Mars transfer. No problems going with recovery for this light payload.

You are assuming that the roadster is the only payload.  What about the Hail Mary, try to land second stage clue?
The roadster could be the '(midnight) cherry on top' of a more ambitious payload.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: lrk on 12/06/2017 12:57 PM
A guy from work was telling me the boosters would not be recovered on this flight. I thought they were. Has there been a change of plans due to the Mars orbit they want to go to?

An early version of an article mistakenly said that and was later changed.  I haven't seen any other information saying the boosters will be expended.
They will be recovered (that is: SpaceX will attempt recovery). Sources at KSC have spotted all three cores in the HIF sporting landing legs. SpaceX doesn't put landing legs on cores they intend to expend.


Cool. That didn't sound right to me but we also thought this was just an LEO flight. Going for escape velocity I wasn't sure if they would have to expend the boosters or not.

An expendable Falcon Heavy could launch about 13 Roadsters to Mars transfer. No problems going with recovery for this light payload.

You are assuming that the roadster is the only payload.  What about the Hail Mary, try to land second stage clue?
The roadster could be the '(midnight) cherry on top' of a more ambitious payload.

I don't see how that is still possible, given that the stage will be on an escape trajectory - unless the Roadster has its own propulsion system attached for the last bit of dV to leave earth orbit. 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/06/2017 12:59 PM
What about the Hail Mary, try to land second stage clue?

I'd like to see them make this stage come back after injecting itself and the roadster into an Earth escape trajectory...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Kaputnik on 12/06/2017 01:28 PM
What about the Hail Mary, try to land second stage clue?

I'd like to see them make this stage come back after injecting itself and the roadster into an Earth escape trajectory...

It's not beyond the laws of physics for the payload to be separated immediately after TMI, and for the US to promptly rotate and make another burn to bring the apogee back down again. You'd then need to wait a whole orbit (with one more burn at apogee) before starting entry. The limit is likely to be stage lifetime rather than propellant.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: crandles57 on 12/06/2017 01:38 PM
I assume they could make apogee less than Mars' perigee.

If it was an instantaneous delta-V you couldn't avoid perigee being below Earth's apogee. However it doesn't have to be an effective instantaneous delta-V, does it? Couldn't they throttle back the engines for a while til further from Earth then give a final delta-V to make the orbit less elliptical so perigee is sufficiently well above Earth's apogee? Also could passing below Mars be used to give a delta-V to make the orbit less elliptical?

(Still not completely safe as an asteroid could pass close and change its orbit but still fairly safe?

Anyway what if roadster was on a collision course with Earth in a few million years, would it burn up fairly harmlessly or reach the surface?)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/06/2017 01:53 PM
What about the Hail Mary, try to land second stage clue?

I'd like to see them make this stage come back after injecting itself and the roadster into an Earth escape trajectory...

It's not beyond the laws of physics for the payload to be separated immediately after TMI, and for the US to promptly rotate and make another burn to bring the apogee back down again. You'd then need to wait a whole orbit (with one more burn at apogee) before starting entry. The limit is likely to be stage lifetime rather than propellant.

Let's run some BOTE numbers. Wikipedia (https://en.wikipedia.org/wiki/Delta-v_budget#Interplanetary) says a typical delta-V requirement from LEO to Mars transfer is 4.6 km/s (although another number shows only 0.6 km/s above C3=0 escape, hmm).

Let's say we take the first number, 7.8 km/s + 4.6 km/s = 12.4 km/s for TMI. To get back to a GTO-like trajectory, you need to reduce those 12.4 or so km/s down to around 10 km/s for GTO perigee velocity. That's 2.5 km/s of delta V right there. 2nd number (0.6 km/s of Oberth effect above C3=0) works out to roughly 2 km/s.  And that only puts you into a several hour long orbit.

Theoretically you wouldn't even need to make another burn at apogee, you could set up perigee right at the reentry burn with some cosine losses, but you'd still probably want to do some kind of burn high up if for nothing else but to control the *timing* of the reentry and hence the reentry groundtrack on the Earth as it rotates under you. Highly eccentric orbits can have large differences in orbital period with small delta-V differences.

2 km/s is not a small number for a kerolox stage, hence why I'm pretty skeptical we'll be seeing this happen.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: speedevil on 12/06/2017 02:21 PM
I don't see how that is still possible, given that the stage will be on an escape trajectory - unless the Roadster has its own propulsion system attached for the last bit of dV to leave earth orbit.

Which raises a question - is there a nearish term goal for such a kick stage for a few million newton-seconds that might appeal to spacex.
Something broadly similar to a STAR48, perhaps.
A simple tank with two superdracos and three tons or so of propellant would almost be a no-brainer.
Almost, not counting the hypergolic nature of the superdracos.

It seems a bit early for a methalox gas thruster as intended for the BFR to be ready, though that might also almost suit.
Fueling such a thruster on the pad might almost be worse than the hypergols though.

https://en.wikipedia.org/wiki/Green_Propellant_Infusion_Mission which is planned for the third FH launch might be in principle interesting, though there have been no signs of interest in exotic hypergols so far.
It would be moderately amusing if they decided on the basis of what they'd seen from integration of the SPIM mission they decided to use it for a highly capable booster. (which would incidentally eat a little of orbital ATKs market potentially)

Following AMOS-6, they're probably unlikely to be willing to do anything too novel without much more thought than simple robust options would give them.

Something like the above would give a pretty nice boost to FH to higher energy orbits.

In principle, it could also allow the second stage in some cases to reenter at a noticably lower speed after staging earlier, simplifying reentry.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 12/06/2017 02:57 PM
Recovering the second stage from TMI is really not "relevant discussion".
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Zed_Noir on 12/06/2017 03:50 PM
I don't see how that is still possible, given that the stage will be on an escape trajectory - unless the Roadster has its own propulsion system attached for the last bit of dV to leave earth orbit.

Which raises a question - is there a nearish term goal for such a kick stage for a few million newton-seconds that might appeal to spacex.
Something broadly similar to a STAR48, perhaps.
A simple tank with two superdracos and three tons or so of propellant would almost be a no-brainer.
Almost, not counting the hypergolic nature of the superdracos.

[snip]

You are thinking too hard. A few Dracos in an array with 3+ tonnes of propellant will be better. No need to developed a vacuum optimized Superdraco. It is the total delta-V that matters.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/06/2017 04:58 PM
The STAR48 disappeared from the F9/FH user manual years ago. Just checked, no mention.

As to TMI, it's not really going to Mars, but an elliptical heliocentric orbit who's apohelion is around Mar's distance from the sun, and perihelion that's Earth's current distance at launch.

Next question to ask is the number of US burns, as well as the downrange for the core. That will tell you something about the mission profile and delta-v requirements. From the launch azimuth and staging, you'll be able to get above/below ecliptic and thus factor in the angular momentum of the earth with the successive vectors of boost, core, and US.

If the plan is to have a least stress launch for the side boosters phase, this light payload won't use the core at all at launch, and go up with enough TWR to clear the tower/facility in less than 30 seconds, then gradually increase thrust to not exceed potential torsional events from TO/uneven thrust, so max Q likely much higher than usual, and possibly staging well before it. Core would ramp just after staging, pass max Q then ramp to maximum, likely also a highly lofted trajectory unless the core burnout requires more downrange to make higher parking/direct injection.

Timing of launch and burn to depletion of US will give you an idea of where the thing is headed above/below the ecliptic.

Would not be surprised if its a direction injection to above the ecliptic with a single US burn no coast, with a highly lofted core burn - then you can track the US/payload post burnout for a few minutes w/o additional resource elsewhere.

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mheney on 12/06/2017 07:20 PM
Please note the "non-payload" part of this thread's title ...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rockets4life97 on 12/06/2017 07:26 PM
Do we know whether these boosters are considered block 3 or block 4? or is that not a relevant category for the first FH?

This launch is somewhat of a one-off with future FH's will be block 5. Is this expected to effect certification?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 12/06/2017 07:28 PM
Do we know whether these boosters are considered block 3 or block 4? or is that not a relevant category for the first FH?

This launch is somewhat of a one-off with future FH's will be block 5. Is this expected to effect certification?

Both boosters are Block 3 since the Block 4 boosters did not start flying until August 2017.

Their first flights were in May and July 2016.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rockets4life97 on 12/06/2017 07:30 PM
Do we know whether these boosters are considered block 3 or block 4? or is that not a relevant category for the first FH?

This launch is somewhat of a one-off with future FH's will be block 5. Is this expected to effect certification?

Both boosters are Block 3 since the Block 4 boosters did not start flying until August 2017.

Their first flights were in May and July 2016.

Yes, my question was getting at whether when the boosters were converted they were also upgraded to block 4.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 12/06/2017 07:36 PM
Do we know whether these boosters are considered block 3 or block 4? or is that not a relevant category for the first FH?

This launch is somewhat of a one-off with future FH's will be block 5. Is this expected to effect certification?

Both boosters are Block 3 since the Block 4 boosters did not start flying until August 2017.

Their first flights were in May and July 2016.

Yes, my question was getting at whether when the boosters were converted they were also upgraded to block 4.

My opinion is that when Block 3 boosters are reused, there's no need to upgrade to Block 4.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 12/06/2017 08:57 PM
Do we know whether these boosters are considered block 3 or block 4? or is that not a relevant category for the first FH?

This launch is somewhat of a one-off with future FH's will be block 5. Is this expected to effect certification?

Both boosters are Block 3 since the Block 4 boosters did not start flying until August 2017.

Their first flights were in May and July 2016.

No, both boosters are Block 2. The center core is Block 3.

And no, rockets4life97, they're still their original Blocks.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 12/06/2017 08:57 PM
I thought Block 2 referred to the v1.1 config.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/06/2017 09:02 PM
I thought Block 2 referred to the v1.1 config.

I thought so to, I think that's a common argument
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Norm38 on 12/06/2017 09:10 PM
So this is finally clear?  Zuma moves to 40 and there’s nothing left to do at 39-A but get this on the pad?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: lrk on 12/06/2017 09:10 PM
I thought Block 2 referred to the v1.1 config.

I thought so to, I think that's a common argument

It has since been confirmed multiple times that the 'blocks' are revisions within 'v1.2'/Full Thrust/F9 upgrade/(whatever the upgrade was that introduced subcooled LOX), but I can't actually seem to find a source at the moment.  I also distinctly remember hearing somewhere that the CRS-8/SES-11 core was a Block 1 booster (also can't remember where, I think maybe on reddit?) 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Formica on 12/06/2017 11:57 PM
So this is finally clear?  Zuma moves to 40 and there’s nothing left to do at 39-A but get this on the pad?

I believe so! Exciting times, FH flow is well underway with no launches in front of it!  :D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/07/2017 12:08 AM
So following CRS13 ... 39A HIF is cleared of Zuma, then booster/US integration, and we see TE tests?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/07/2017 12:16 AM
So following CRS13 ... 39A HIF is cleared of Zuma, then booster/US integration, and we see TE tests?

I wouldn't be surprised to see rollout and fit checks in about 1.5-2 weeks.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/07/2017 12:44 AM
So following CRS13 ... 39A HIF is cleared of Zuma, then booster/US integration, and we see TE tests?

I wouldn't be surprised to see rollout and fit checks in about 1.5-2 weeks.

True, it's most likely that the delays will likely come after that, as they master fueling/safeing/draining.

With LC40 back to normal operation (will take a 2-3 launches before that settles down), they can accept the delay of sorting out all the details of processing, sequencing, and proving the multiple cores/GSE work, and the launch conductor procedures/aborts/restarts/sequencing has no surprises. It'll likely be quite a challenge to track all 27 engine characteristics stepping through the cold flows, feed lines, cryogenic "effects", as we have chilled propellants (another first here, a clustered vehicle with them, sure to have surprises). Lots of little details to reconcile, building to ignition sequencing (outboard to inner? staggered shutdown? cavitation?).

So likely a very tedious December/January, even if we see a roll-out so soon.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: oiorionsbelt on 12/07/2017 01:02 AM
So following CRS13 ... 39A HIF is cleared of Zuma, then booster/US integration, and we see TE tests?

I wouldn't be surprised to see rollout and fit checks in about 1.5-2 weeks.

True, it's most likely that the delays will likely come after that, as they master fueling/safeing/draining.

With LC40 back to normal operation (will take a 2-3 launches before that settles down), they can accept the delay of sorting out all the details of processing, sequencing, and proving the multiple cores/GSE work, and the launch conductor procedures/aborts/restarts/sequencing has no surprises. It'll likely be quite a challenge to track all 27 engine characteristics stepping through the cold flows, feed lines, cryogenic "effects", as we have chilled propellants (another first here, a clustered vehicle with them, sure to have surprises). Lots of little details to reconcile, building to ignition sequencing (outboard to inner? staggered shutdown? cavitation?).

So likely a very tedious December/January, even if we see a roll-out so soon.
Sounds like some BFR BFS applicable knowledge.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisC on 12/07/2017 01:38 PM
Thank you gongora for splitting up the threads and finally giving us an updates-only thread!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Proponent on 12/07/2017 02:13 PM
2 km/s is not a small number for a kerolox stage, hence why I'm pretty skeptical we'll be seeing this happen.

That's true, but this stage would be lightly loaded for the TMI burn and completely unloaded after that, which should improve the delta-V noticeably.

EDIT:  "loaded" -> "unloaded" (rather crucial!)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Basto on 12/07/2017 02:15 PM
Sorry if I missed this but has the TEL been moved back into the HIF?  Last I heard it was on the pad for modifications.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/07/2017 02:21 PM
2 km/s is not a small number for a kerolox stage, hence why I'm pretty skeptical we'll be seeing this happen.

That's true, but this stage would be lightly loaded for the TMI burn and completely loaded after that, which should improve the delta-V noticeably.
I think you have that backwards, but good point. What's the mass ratio between a roadster and an FH S2?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jjyach on 12/07/2017 02:55 PM
Sorry if I missed this but has the TEL been moved back into the HIF?  Last I heard it was on the pad for modifications.

I believe yesterday it was still up at the pad.  Most of the crews at 39A went over to 40 to help.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Proponent on 12/07/2017 03:27 PM
That's true, but this stage would be lightly loaded for the TMI burn and completely loaded after that, which should improve the delta-V noticeably.
I think you have that backwards, but good point. What's the mass ratio between a roadster and an FH S2?

Quite right, I meant unloaded and have corrected my previous post accordingly.

This site (https://www.vehiclehistory.com/vehicle-curb-weight-specifications/tesla/roadster/2010) gives 2690 kg for a 2010 Tesla Roadster.  And this one won't need its full complement batteries, so it could easily be quite a bit lighter.  Either way, it's much less than Falcon Heavy (http://www.spacex.com/falcon-heavy)'s stated TMI payload of 16,800 kg.

On the Falcon simulation threads, someone must have worked pretty hard on estimating the stage's relevant masses, but let's start with Space Launch Report (http://spacelaunchreport.com/falconH.html)'s estimates that the stage's dry mass at about 4100 kg and the propellant load a bit over 100,000 kg.  So, with the standard TMI payload, the mass ratio is 5.79 and the delta-V is 6000 m/s, assuming a vacuum specific impulse of 348 s.

Replace the standard TMI payload with a Tesla Roadster, and we've got a mass ratio of 15.7 and a delta-V of 9400 m/s.  In other words, we pick up an extra 3400 m/s, even if we assume that the Roadster remains attached to depletion.  And we actually do a little better than that, since the delta-V provided by the boosters and first stage will increase a bit due to the decreased payload mass.  Jettison the Roadster after TMI, and the delta-V increases further.

These numbers are rough, but they do suggest there is some delta-V to play with.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 12/07/2017 03:31 PM
That's true, but this stage would be lightly loaded for the TMI burn and completely loaded after that, which should improve the delta-V noticeably.
I think you have that backwards, but good point. What's the mass ratio between a roadster and an FH S2?

Quite right, I meant unloaded and have corrected my previous post accordingly.

This site (https://www.vehiclehistory.com/vehicle-curb-weight-specifications/tesla/roadster/2010) gives 2690 kg for a 2010 Tesla Roadster.  And this one won't need its full complement batteries, so it could easily be quite a bit lighter.  Either way, it's much less than Falcon Heavy (http://www.spacex.com/falcon-heavy)'s stated TMI payload of 16,800 kg.

On the Falcon simulation threads, someone must have worked pretty hard on estimating the stage's relevant masses, but let's start with Space Launch Report (http://)'s estimates that the stage's dry mass at about 4100 kg and the propellant load a bit over 100,000 kg.  So, with the standard TMI payload, the mass ratio is 5.79 and the delta-V is 6000 m/s, assuming a vacuum specific impulse of 348 s.

Replace the standard TMI payload with a Tesla Roadster, and we've got a mass ratio of 15.7 and a delta-V of 9400 m/s.  In other words, we pick up an extra 3400 m/s, even if we assume that the Roadster remains attached to depletion.  And we actually do a little better than that, since the delta-V provided by the boosters and first stage will increase a bit due to the decreased payload mass.  Jettison the Roadster after TMI, and the delta-V increases further.

These numbers are rough, but they do suggest there is some delta-V to play with.

Those are pounds, not kg. See the curb weight at Car and Driver:
https://www.caranddriver.com/reviews/2010-tesla-roadster-sport-instrumented-test
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Nomadd on 12/07/2017 03:38 PM


This site (https://www.vehiclehistory.com/vehicle-curb-weight-specifications/tesla/roadster/2010) gives 2690 kg for a 2010 Tesla Roadster.  And this one won't need its full complement batteries, so it could easily be quite a bit lighter.  Either way, it's much less than Falcon Heavy (http://www.spacex.com/falcon-heavy)'s stated TMI payload of 16,800 kg.

On the Falcon simulation threads, someone must have worked pretty hard on estimating the stage's relevant masses, but let's start with Space Launch Report (http://)'s estimates that the stage's dry mass at about 4100 kg and the propellant load a bit over 100,000 kg.  So, with the standard TMI payload, the mass ratio is 5.79 and the delta-V is 6000 m/s, assuming a vacuum specific impulse of 348 s.

Replace the standard TMI payload with a Tesla Roadster, and we've got a mass ratio of 15.7 and a delta-V of 9400 m/s.  In other words, we pick up an extra 3400 m/s, even if we assume that the Roadster remains attached to depletion.  And we actually do a little better than that, since the delta-V provided by the boosters and first stage will increase a bit due to the decreased payload mass.  Jettison the Roadster after TMI, and the delta-V increases further.

These numbers are rough, but they do suggest there is some delta-V to play with.

Those are pounds, not kg. See the curb weight at Car and Driver:
https://www.caranddriver.com/reviews/2010-tesla-roadster-sport-instrumented-test
Where were you when the Mars Climate Orbiter was on it's way?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 12/07/2017 03:59 PM
Sorry if I missed this but has the TEL been moved back into the HIF?  Last I heard it was on the pad for modifications.

I believe yesterday it was still up at the pad.  Most of the crews at 39A went over to 40 to help.
I recall that a final 2 week stint on the pad is required to finish everything for FH and that started when ZUMA's launcher was demated from the TEL and the TEL rolled back out and fully secured at the pad.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Formica on 12/07/2017 04:51 PM
All credit to u/TheRealWhiskers on Reddit. (https://www.reddit.com/r/spacex/comments/7hjp03/falcon_heavy_demo_launch_campaign_thread/dqwgon3/?sh=255045d1&st=JAWL3YTA) Here's some shots of the TEL at 39A and a peek inside the HIF. All eight holddowns are clearly installed and the F9 baskets can be seen removed from the base. The pictures were taken over the past three days.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: StuffOfInterest on 12/07/2017 06:45 PM
The picture of the pickup next to the baskets sure gives a sense of scale.

I can see the hold-downs, but can any confirm if the rest of the tail service masts have been installed?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 12/07/2017 07:15 PM
All TSM's have been installed to the reaction frame, which is visibly confirmed by your photo and the pictures in Formica's post.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rsdavis9 on 12/07/2017 07:49 PM
For the "what an object looks like" challenged...

The baskets are right above the pickup truck to the right and left?
I thought those looked like the hold down clamps?
Can somebody help me and put an arrow to a basket and a clamp?
Also what does the basket do?

thanks
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/07/2017 07:54 PM
The baskets are the white framework either side of the pickup. They support the weight of the rocket when it's vertical.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/07/2017 07:58 PM
Just to add a bit more clarity - the baskets are the white structures that live on the underside of the frame. The hold downs are attached to the baskets. You are seeing both the removed hold downs AND the baskets. All one structure.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Bob Shaw on 12/07/2017 08:16 PM
What I’m reading here suggests to me that one of Musk’s objectives with this launch might be bragging rights regarding his Tesla making a fast transit to the distance of Mars (though IIRC Pioneer 10 & 11 are likely to remain the fastest spacecraft, his Tesla would be the first and fastest man-rated vehicle to make the journey). And yes, I appreciate that this thread isn’t about payloads, but I reckon that the trajectory aspect makes this the appropriate place for this post!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris_Pi on 12/10/2017 07:15 PM
In that last photo through the open HIF door, Am I seeing a Heavy center/side core top connection with maybe a S2 in front of the side core? I think that's what it is.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: shuttlefan on 12/10/2017 07:46 PM
So is 39-A still capable of launching a Falcon 9 or has the configuration for Falcon Heavy taken that capability away?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cppetrie on 12/10/2017 07:57 PM
So is 39-A still capable of launching a Falcon 9 or has the configuration for Falcon Heavy taken that capability away?
Still can do single sticks. Just swap out compression bridges and swap in hold down baskets. Probably a day or two op max.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jpo234 on 12/10/2017 09:14 PM
So is 39-A still capable of launching a Falcon 9 or has the configuration for Falcon Heavy taken that capability away?
Since 39A is the pad for Commercial Crew, it has to be able to handle regular F9s.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vaporcobra on 12/10/2017 09:54 PM
Pro tip: If you have time to ask questions about it here, please please please read around a bit first (SpaceNews, NASASpaceflight (!), Florida Today, etc.). Articles posted this week alone can answer all your questions and then some, more likely than not.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Michael Baylor on 12/11/2017 03:50 PM
SpaceX's Jenson at the CRS13 press conference confirms that the Falcon Heavy static fire is still on for this year. Launch will take place "a few weeks after that." All regulations are being followed for the Tesla Roadster.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AbuSimbel on 12/11/2017 05:15 PM
The original plan was to fit test FH by the end of November and Fire it 15 days later. If the SF is now slated for the end of December we should see the beast vertical on the pad soon. A few days after CRS-13 maybe?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jimvela on 12/14/2017 12:05 AM
No idea if this actually belongs in this section, but...
I was taking a sponsored community college kid on a bus tour at KSC a few days back on the 8th.
We got stopped by the escort vehicles for... this.
Headed to 39A as far as I could tell...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: octavo on 12/14/2017 03:57 AM
No idea if this actually belongs in this section, but...
I was taking a sponsored community college kid on a bus tour at KSC a few days back on the 8th.
We got stopped by the escort vehicles for... this.
Headed to 39A as far as I could tell...
That looks like a payload fairing... Zuma?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jarnis on 12/14/2017 07:31 AM
More like for FH?

Zuma is supposed to go from 40, no?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ludovic_f on 12/14/2017 12:37 PM
But the core + S2 are still in LC39A HIF, are they not?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 12/14/2017 12:41 PM
Is the item in the picture even big enough to be a fairing?

It would be unusual for a fairing without a payload already in it to go to LC-39A.  There isn't a payload processing facility at that pad.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/14/2017 01:46 PM
I'd say it's about the size of a Gen 1 Roadster, possibly red, and associated bits (whatever those are)...

(I know this comment isn't non-payload, but I actually think I may be right :-) )
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 12/14/2017 02:04 PM
I'd say it's about the size of a Gen 1 Roadster, possibly red, and associated bits (whatever those are)...

(I know this comment isn't non-payload, but I actually think I may be right :-) )

As gongora just noted, there's no payload processing facility on the pad. Why would the payload go there unencapsulated, instead of going through the normal process like every other SpaceX payload?

Are the compression bridges already installed? The bottom half of that looks like one, although the top profile doesn't. Maybe it's covered with something under the tarp.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rockets4life97 on 12/14/2017 02:13 PM
Static fire with the payload on? Seems like losing the car is part of the PR deflection in case of a failure.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Nomadd on 12/14/2017 02:21 PM
Is the item in the picture even big enough to be a fairing?

It would be unusual for a fairing without a payload already in it to go to LC-39A.  There isn't a payload processing facility at that pad.
Not even close. That thing's about half the diameter of a fairing.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jim on 12/14/2017 06:45 PM
No idea if this actually belongs in this section, but...
I was taking a sponsored community college kid on a bus tour at KSC a few days back on the 8th.
We got stopped by the escort vehicles for... this.
Headed to 39A as far as I could tell...

Maybe it should be in the Blue Origin LC-36 section?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 12/14/2017 07:33 PM
Heavy breathing!

HAWTHORNE, Calif. – Dec. 14, 2017. Media accreditation is now open for Falcon Heavy’s Demonstration Mission from Launch Complex 39A (LC-39A) at Kennedy Space Center in Florida. The launch is targeted for January 2018.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jim on 12/14/2017 07:41 PM
No idea if this actually belongs in this section, but...
I was taking a sponsored community college kid on a bus tour at KSC a few days back on the 8th.
We got stopped by the escort vehicles for... this.
Headed to 39A as far as I could tell...

Where exactly was this?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jimvela on 12/14/2017 08:21 PM
Where exactly was this?

Just up the road from 39A, in the KSC tour bus.
I thought I recognized that transporter as one of the ones that SpaceX bought as surplus from NASA, but I'm not certain.

I wasn't able to watch it actually enter 39A as shortly after it passed, the tour bus went back on its way.

The door at 39A was open just before as we passed it, but as is my practice did not shoot photos into the building nor of the escort (security) vehicles. 

Just prior to this I did grab a few shots of the TE that was out at 39A.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jimvela on 12/14/2017 08:32 PM
Looks like something on casters on the flatbed, under a tarp, which is on top of tubed ribbing to keep from giving away shape otherwise.

It would be kinda dumb to not process a payload in "payload processing", but it's not supposes to be an active payload  but a peculiar mass simulator, possibly bolted to the payload adapter? So one presumes in this case, it's CG has been located, contents have been prepared/passivated, and all that remains is to bolt it in position to the payload adapter, then the mated pair of fairing secured? Goofy but possible.

Yes, my thoughts were that this was something on a transport cart of some kind.  That white transport cart looks similar to countless others I've seen over the years.

I couldn't decide if the "arms" under the tarp were structure or possibly just straps securing something to the transport cart below, with the tarp just hastily thrown over.

I mulled about in my head whether perhaps it was something for the Transproter/Erector, strapped to a transport cart, but it didn't really have that sort of feel to it as I watched it go by.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: JoerTex on 12/15/2017 01:13 PM
Go to the payload discussion for talk about a Red Tesla.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Inoeth on 12/15/2017 03:19 PM
I'm sure you guys noticed, we did get to see both landing pads, with the second one looking fully completed with a new paint job as F9 came in for a landing during this morning's CRS 13 mission.  Very happy to see that looking finished as to me that's one more point in favor of this rocket launching sooner than later.

Any word on when they''ll be doing the wet dress rehearsal and the static fire (I know they said before the end of December) but id love to see this beast vertical on the pad- it'll make it that much more real after all the years of delays.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: karki on 12/15/2017 05:01 PM
I'm sure you guys noticed, we did get to see both landing pads, with the second one looking fully completed with a new paint job as F9 came in for a landing during this morning's CRS 13 mission.  Very happy to see that looking finished as to me that's one more point in favor of this rocket launching sooner than later.

Any word on when they''ll be doing the wet dress rehearsal and the static fire (I know they said before the end of December) but id love to see this beast vertical on the pad- it'll make it that much more real after all the years of delays.

I'm interested to know why they painted the new one white? I believe the black paint on the main landing pad helps with sensors that determine distance (radar?) so did they figure out how to make the same sensors work just as well with white paint or is there something different about these updated boosters?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/15/2017 05:50 PM
There is radar-reflective paint on the first pad, but perhaps it comes in multiple colors? Alternatively, we're seeing a base coat, and the radar-reflective stuff will be added on top of that.

A bunch of other options, too: since they knew they'd need the additional radar-reflectivity before the started work on the pad, perhaps the radar-reflective layer is below the surface top coat.  Or (as I seem to recall hearing somewhere in NSF) they could have integrated the radar-reflective materials into the concrete (maybe just extra rebar?) and not need the paint.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/15/2017 07:05 PM
No idea if this actually belongs in this section, but...
I was taking a sponsored community college kid on a bus tour at KSC a few days back on the 8th.
We got stopped by the escort vehicles for... this.
Headed to 39A as far as I could tell...
Whatever that thing is - it's sitting on a wheeled dolly - like the kind of thing you see when moving a payload around on a nice clean level floor (there is very little clearance beneath the carriage for anything other than a concrete floor)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 12/15/2017 07:17 PM
We don't actually know that the thing in the picture has anything to do with SpaceX.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 12/15/2017 07:18 PM
We don't actually know that the thing in the picture has anything to do with SpaceX.
Like that's gonna stop us.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: abaddon on 12/15/2017 07:48 PM
Given this is the non-payload discussion thread, unless anyone thinks it's a part of the rocket (seems like the general consensus is "no"), this is off-topic and should be discussed elsewhere, no?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/15/2017 08:13 PM
We don't actually know that the thing in the picture has anything to do with SpaceX.
Like that's gonna stop us.
Back in the early days at the Cape people would stare at the lighthouse from far away thinking it was a rocket sitting on the pad... ;D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: MATTBLAK on 12/15/2017 08:21 PM
Heavy breathing!

HAWTHORNE, Calif. – Dec. 14, 2017. Media accreditation is now open for Falcon Heavy’s Demonstration Mission from Launch Complex 39A (LC-39A) at Kennedy Space Center in Florida. The launch is targeted for January 2018.

Come for a visit and cover it here!  Well put you up for a few days Chris!
The launch I want to be at with Accreditation is the FH/Dragon with lunar tourists - if and when they do it (2018-2020)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: MATTBLAK on 12/15/2017 08:30 PM
We don't actually know that the thing in the picture has anything to do with SpaceX.
Like that's gonna stop us.
Back in the early days at the Cape people would stare at the lighthouse from far away thinking it was a rocket sitting on the pad... ;D
When I was a kid here in Auckland; directly though my kitchen window at night I could see the One Tree Hill monument lit up in the distance. I used to think that it looked like a rocket on the pad:

https://i.pinimg.com/474x/a4/da/f1/a4daf10310d7d5e813560367febd9f41--one-tree-hill-auckland.jpg

https://i.pinimg.com/564x/c6/8f/c9/c68fc945780b80b814513ea210214599--one-tree-hill-auckland-new-zealand.jpg
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Michael Baylor on 12/16/2017 01:46 AM
I measured the distance between the two landing zones using the new Planet Labs measuring tool. They are only ~300 meters apart from center to center. The landing is going to be even more epic than I thought! I knew they would be close, but less than 1/5 of a mile close?  8)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jcc on 12/16/2017 01:51 PM
I measured the distance between the two landing zones using the new Planet Labs measuring tool. They are only ~300 meters apart from center to center. The landing is going to be even more epic than I thought! I knew they would be close, but less than 1/5 of a mile close?  8)

I'm kind of curious about why one pad it black and the other white. If the black paint is radar reflective to make landings more precise, did they find radar reflective white paint, or integrate equivalent or better reflectivity in the concrete?

Or just to make it look cool.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 12/16/2017 02:26 PM
I'm guessing the radar reflective paint is an underneath, and what were seeing is just a weather and heat resistant overcoat.

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Saabstory88 on 12/16/2017 03:30 PM
I'm kind of curious about why one pad it black and the other white. If the black paint is radar reflective to make landings more precise, did they find radar reflective white paint, or integrate equivalent or better reflectivity in the concrete?

Or just to make it look cool.

Well, if you wanted to test different coatings, then having two boosters landing at the same time would control for weather conditions and time of day.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CuddlyRocket on 12/16/2017 03:31 PM
I'm kind of curious about why one pad it black and the other white. If the black paint is radar reflective to make landings more precise, did they find radar reflective white paint, or integrate equivalent or better reflectivity in the concrete?
Perhaps there's a difference in the radar reflectivity of the two pads to enable the individual boosters to distinguish between the two, thereby reducing the chances of one booster getting confused and both attempting to land at the same pad?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/16/2017 03:35 PM
I think it's just refinement of pad construction using lessons learned. If we see a third pad built, I bet it looks just like the second pad.

Unless, of course, it has a cradle for BFR.  Then all bets are off and it's unexplored R&D territory again.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: pb2000 on 12/16/2017 03:38 PM
Could also be the pads will be colour coded. If a third one is built for 3 core RTLS, I wouldn't be surprised if it was painted blue with a white X. Makes a it a lot easier to understand where each core is suppose to go and reduce the likelihood of one core thinking it was a second stage and trying to land on the interstage of the other  ;D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Nomadd on 12/16/2017 03:49 PM
I'm kind of curious about why one pad it black and the other white. If the black paint is radar reflective to make landings more precise, did they find radar reflective white paint, or integrate equivalent or better reflectivity in the concrete?
Perhaps there's a difference in the radar reflectivity of the two pads to enable the individual boosters to distinguish between the two, thereby reducing the chances of one booster getting confused and both attempting to land at the same pad?
I'm pretty sure radar is just for the altimeter.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/16/2017 03:52 PM
Maybe they made a white radar-reflective paint, or they're just happy with its accuracy without the special paint.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: shuttlefan on 12/16/2017 04:03 PM
Have the strap-ons been mated to the core?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 12/16/2017 05:27 PM
Have the strap-ons been mated to the core?
I think the preferred term is side booster? Strap-ons? Mating? Might be a different forum you're thinking of?

That said I think they have been but we haven't seen any public pics yet IIRC.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: TaurusLittrow on 12/16/2017 06:23 PM
Heavy breathing!

HAWTHORNE, Calif. – Dec. 14, 2017. Media accreditation is now open for Falcon Heavy’s Demonstration Mission from Launch Complex 39A (LC-39A) at Kennedy Space Center in Florida. The launch is targeted for January 2018.

Wouldn't media accreditation/badging be through NASA/KSC given that the launch is from 39A?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: shuttlefan on 12/16/2017 06:23 PM
Have the strap-ons been mated to the core?
I think the preferred term is side booster? Strap-ons? Mating? Might be a different forum you're thinking of?

That said I think they have been but we haven't seen any public pics yet IIRC.

Even though I thought you were too critical of my wording, thanks for the answer! :D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: clongton on 12/16/2017 06:27 PM
Have the strap-ons been mated to the core?
I think the preferred term is side booster? Strap-ons? Mating? Might be a different forum you're thinking of?

That said I think they have been but we haven't seen any public pics yet IIRC.

The term in longest use in the industry is strap-on boosters. I remember this term from back in the 60's and 70's. But there are many variations and almost any of them are readily identifiable for what they are.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: the_other_Doug on 12/17/2017 03:45 AM
Have the strap-ons been mated to the core?
I think the preferred term is side booster? Strap-ons? Mating? Might be a different forum you're thinking of?

That said I think they have been but we haven't seen any public pics yet IIRC.

The term in longest use in the industry is strap-on boosters. I remember this term from back in the 60's and 70's. But there are many variations and almost any of them are readily identifiable for what they are.

It's been an AWFUL long time since some members of this forum have thought about anything except in terms of rockets, it appears.

C'mon, guys -- humans are animals too, y'know... :D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Nomadd on 12/17/2017 04:49 AM
Have the strap-ons been mated to the core?
I think the preferred term is side booster? Strap-ons? Mating? Might be a different forum you're thinking of?

That said I think they have been but we haven't seen any public pics yet IIRC.

The term in longest use in the industry is strap-on boosters. I remember this term from back in the 60's and 70's. But there are many variations and almost any of them are readily identifiable for what they are.
At least they don't look like New Shepard.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 12/17/2017 05:42 AM
Have the strap-ons been mated to the core?
I think the preferred term is side booster? Strap-ons? Mating? Might be a different forum you're thinking of?

That said I think they have been but we haven't seen any public pics yet IIRC.

Even though I thought you were too critical of my wording, thanks for the answer! :D

I wasn't CRITICAL, I was having some fun with it. As often is my wont, because I love words and word play...

I'll elaborate a bit further, I now know for a fact the side boosters have been connected to the center core but that's all I can say. That really shouldn't be all that surprising given the calendar...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: docmordrid on 12/17/2017 09:19 AM
Have the strap-ons been mated to the core?
I think the preferred term is side booster? Strap-ons? Mating? Might be a different forum you're thinking of?

That said I think they have been but we haven't seen any public pics yet IIRC.

The term in longest use in the industry is strap-on boosters. I remember this term from back in the 60's and 70's. But there are many variations and almost any of them are readily identifiable for what they are.
At least they don't look like New Shepard.

My first thought on seeing NS was "Flesh Gordon!"

/sorry
/sort of
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: shuttlefan on 12/17/2017 01:01 PM
Have the strap-ons been mated to the core?
I think the preferred term is side booster? Strap-ons? Mating? Might be a different forum you're thinking of?

That said I think they have been but we haven't seen any public pics yet IIRC.

Even though I thought you were too critical of my wording, thanks for the answer! :D

I wasn't CRITICAL, I was having some fun with it. As often is my wont, because I love words and word play...

I'll elaborate a bit further, I now know for a fact the side boosters have been connected to the center core but that's all I can say. That really shouldn't be all that surprising given the calendar...

I apologize for taking you the wrong way, Lar. Thanks again for that information.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Tea Party Space Czar on 12/18/2017 05:16 PM
Just like Falcon pushed the ball forward - Falcon Heavy will open the gateway to the moon... and beyond.

Hang in there kids.

Respectfully,
Andrew Gasser
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: JAFO on 12/18/2017 05:59 PM
Have the strap-ons been mated to the core?
I think the preferred term is side booster? Strap-ons? Mating? Might be a different forum you're thinking of?

That said I think they have been but we haven't seen any public pics yet IIRC.

The term in longest use in the industry is strap-on boosters. I remember this term from back in the 60's and 70's. But there are many variations and almost any of them are readily identifiable for what they are.

It's been an AWFUL long time since some members of this forum have thought about anything except in terms of rockets, it appears.

C'mon, guys -- humans are animals too, y'know... :D


We know that rockets aren’t Legos, but the way we talk about them, I believe a lot of us feel like rockets are human, or at least, sentinent.


(In before the trim, btw.)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 12/18/2017 07:30 PM
This thread is specifically for the demo mission.  Let's please get this back on topic.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: sevenperforce on 12/18/2017 07:38 PM
In CRS-13, the camera angle made it look like the booster flipped horizontally (yaw-wise) rather than vertically (pitch-wise). This was not the case, but it got me thinking...if the side boosters for Heavy do a yaw-flip rather than a pitch-flip, then boostback would tend to push them further away from each other, providing additional clearance and reducing the chance of interactions.

I'd imagine they'd want the closest approach (after separation) to be the landing itself.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/18/2017 08:03 PM
It does get me thinking, though. Ideally, they'd want as much separation between the two side boosters as possible, to prevent any possible interactions. Flipping horizontally and firing up the three boostback engines mid-flip would push the boosters as far away from each other as possible; then they'd be following a trajectory such that their closest approach would be the landing burn itself.

If you're talking about Falcon Heavy, they way the 2 thruster pods are located with respect to the booster raceways makes me think they might actually employ a combination of Delta IV Heavy separation (sideways) and Titan IV SRM separation (one mostly goes "up", the other "down"). FH side boosters only have one useful cold gas thruster pointed toward the center core (and has the problem of pushing the engine section actually *toward* the center core since it's below booster center of gravity), but two useful ones pointed sideways ("up/down" in this view, one pod on either side of the core). All things being equal that means they could impart a greater angular acceleration vertically. Something kind of like this type of motion as sketched below, primarily motion of the *top* of the booster, the engine section is heavier and would see less movement. That's probably what Titan SRMs do as well, but it mostly looks like they peel off in an up/down fashion)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: shuttlefan on 12/19/2017 12:38 AM
Any set date yet for rollout to Pad A for fit checks, static fire, etc.? ;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 12/19/2017 12:49 AM
Any set date yet for rollout to Pad A for fit checks, static fire, etc.? ;)
nothing at this time.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deadman719 on 12/19/2017 12:54 AM
I'd explain more as how this would apply to this and other potential missions, but it's the wrong thread for that apparently.

Only for the Demo mission, not for FH specific items, or other missions.

But, you should closely watch for how "horizontal staging" works on this Demo mission. SX has had problems with staging on other inaugural flights of new vehicles, especially Falcon 1, where they had issues for consecutive missions with recontact.

Watch for booster engine cutoff, notice if the combined vehicle "twists" (there are multiple engines, they don't tail-off all the same) or "oscillates" - the boosters should be entirely passive before separation.

One means that has worked well for SX separation events has been spring separation - constant force through distance (F=kX) rather than thrusters (or other) means a predictable trajectory that avoids contact (thrusters have variable impulse requiring different amounts of time to get the same cumulative force).

Also, observe the roll of the core and stages, to see if residual torques from the spin-down of the turbopumps/gas generators.
Could the thrusters be used to null out any roll that is induced during the spin-down?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Wolfram66 on 12/19/2017 02:09 AM
I'm kind of curious about why one pad it black and the other white. If the black paint is radar reflective to make landings more precise, did they find radar reflective white paint, or integrate equivalent or better reflectivity in the concrete?
Perhaps there's a difference in the radar reflectivity of the two pads to enable the individual boosters to distinguish between the two, thereby reducing the chances of one booster getting confused and both attempting to land at the same pad?
I'm pretty sure radar is just for the altimeter.

So true, Nomadd. Also each booster has the GPS coordinates preprogrammed into return flight paths. Same reason why S1’s don’t try and land on GO twins instead of OCISLY
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: fthomassy on 12/19/2017 10:36 AM
... constant force through distance (F=kX) ...
Not constant force. Unless you claim SX uses non-linear springs.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/19/2017 02:07 PM
Strap-on boosters or rocket motors (for solids) is an accepted terminology... For Falcon Heavy it may make sense for terminology to use; Booster one flies back to LZ-1 and Booster two to LZ-2, Core to Drone Ship... IMHO
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 12/19/2017 02:49 PM
... constant force through distance (F=kX) ...
Not constant force. Unless you claim SX uses non-linear springs.
...or with negative Hook’s constants.
In fact, the comment is backwards. Thrusters provide constant thrust. Springs are nonlinear.

Space Ghost’s other comments are good:  They need stable systems to avoid unmodeled torques so the can get clean separation and prevent recontact.

Personally I would think they would leave the center engines running to fly the boosters away from the core, but we will see their choices soon enough.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: john smith 19 on 12/19/2017 03:14 PM

If you looked at the inaugural launches for many vehicles, they had a slight roll rate (Falcon 1, 9, and most recently Electron) - that is because the estimated control to counteract the vehicle's movement (roll) wasn't sufficient.
Most notoriously on one of the Ariane 5 upgrades when the cooling channel in the nozzle was spiral and apparently got the flow spinning. Not easy to start, but not easy to stop either. :(
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/19/2017 03:46 PM
The booster "cradle separation" method used on JAXA's HII is also interesting...
http://global.jaxa.jp/projects/rockets/h2a/f8/pdf/h-2af8.pdf
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: LouScheffer on 12/19/2017 03:52 PM
Personally I would think they would leave the center engines running to fly the boosters away from the core, but we will see their choices soon enough.
Keeping one engine burning seems reasonable.  They can throttle one down to about 300 kN.  The side booster masses at least 40,000 kg at that point (something like 27,000 at landing, plus boostback and re-entry burn fuel).  So at most 7.5 m/s^2 acceleration for the side booster.  Meanwhile the core has 9 engines x 845 kN = 7.6 MN.  Mass is at most 600,000 kg (that would be a full center booster (450,000 kg) plus a massive second stage + payload (this was at 125.000 kg for Falcon 9)).  So acceleration is at least 12.6 m/s and probably much more.  So the center core is definitely pulling away from the side cores, even though they still have an engine running.

However, if I had to pick an engine to keep running, I'd pick the one closest to the center core. This would add torque to point the side booster away from the core.  From previous estimates (https://forum.nasaspaceflight.com/index.php?topic=43255.msg1699331#msg1699331), we can guess the moment of inertia of the core about the engines to be about 15,000,000 kg/m^2.   300,000 N applied 1.66 m from the center line is about 500,000 N-m of torque.  This gives an angular acceleration of about 1/3 radian/s^2, or about 20 degrees in a second.  At this point the engine is pushing the booster away from the core at a substantial fraction of a G, and under very positive control.  The cold gas thrusters can help too.

Using the center engine is also possible, but the separation would be slower.  But maybe it's enough, and the center engine is already plumbed to run by itself.  Only SpaceX knows for sure....
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 12/19/2017 04:05 PM
Personally I would think they would leave the center engines running to fly the boosters away from the core, but we will see their choices soon enough.
Keeping one engine burning seems reasonable.  They can throttle one down to about 300 kN.  The side booster masses at least 40,000 kg at that point (something like 27,000 at landing, plus boostback and re-entry burn fuel).  So at most 7.5 m/s^2 acceleration for the side booster.  Meanwhile the core has 9 engines x 845 kN = 7.6 MN.  Mass is at most 600,000 kg (that would be a full center booster (450,000 kg) plus a massive second stage + payload (this was at 125.000 kg for Falcon 9)).  So acceleration is at least 12.6 m/s and probably much more.  So the center core is definitely pulling away from the side cores, even though they still have an engine running.

However, if I had to pick an engine to keep running, I'd pick the one closest to the center core. This would add torque to point the side booster away from the core.  From previous estimates (https://forum.nasaspaceflight.com/index.php?topic=43255.msg1699331#msg1699331), we can guess the moment of inertia of the core about the engines to be about 15,000,000 kg/m^2.   300,000 N applied 1.66 m from the center line is about 500,000 N-m of torque.  This gives an angular acceleration of about 1/3 radian/s^2, or about 20 degrees in a second.  At this point the engine is pushing the booster away from the core at a substantial fraction of a G, and under very positive control.  The cold gas thrusters can help too.

Using the center engine is also possible, but the separation would be slower.  But maybe it's enough, and the center engine is already plumbed to run by itself.  Only SpaceX knows for sure....

Using the closest engine to core would tend to push tail into core engines... want the opposite effect.  Use the center engine and when the nose is rotating away from center core at good rate, use TVC to kick tail away from center core.  You'd be neutralizing some of the rotation, but physically pushing the tail away from contact.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: shuttlefan on 12/19/2017 05:15 PM
I would think with the static fire at the end of the month they would roll it out to the pad any day now for fit checks, etc.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: LouScheffer on 12/19/2017 05:22 PM
Using the closest engine to core would tend to push tail into core engines... want the opposite effect.  Use the center engine and when the nose is rotating away from center core at good rate, use TVC to kick tail away from center core.  You'd be neutralizing some of the rotation, but physically pushing the tail away from contact.

If they can vector the closest engine enough to point through the center of gravity, then they can push away from the core without imparting any rotation.  In combination with the gas jets at the top, this should allow pure translation away from the core, then use thrust vectoring to keep it away.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: GWH on 12/19/2017 05:43 PM
Hey guys there is already a multi page thread discussing this issue: https://forum.nasaspaceflight.com/index.php?topic=43255.0
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mdeep on 12/19/2017 07:00 PM
I want to pull this in from the update thread:

FAA thinks launch is close:

Quote
Second day of the Next-Generation Suborbital Researchers Conference starts with keynotes by FAA’s George Nield and NASA’s Steve Jurczyk. #NSRC2017
https://twitter.com/jeff_foust/status/943132943383453697 (https://twitter.com/jeff_foust/status/943132943383453697)

Quote
Nield: 2017 has been pretty exciting for commercial spaceflight, but 2018 will be even more exciting, starting with Falcon Heavy first launch in the next month. #NSRC2017
https://twitter.com/jeff_foust/status/943135747477065728 (https://twitter.com/jeff_foust/status/943135747477065728)

FH before Zuma?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 12/19/2017 07:16 PM
I want to pull this in from the update thread:

FAA thinks launch is close:

Quote
Second day of the Next-Generation Suborbital Researchers Conference starts with keynotes by FAA’s George Nield and NASA’s Steve Jurczyk. #NSRC2017
https://twitter.com/jeff_foust/status/943132943383453697 (https://twitter.com/jeff_foust/status/943132943383453697)

Quote
Nield: 2017 has been pretty exciting for commercial spaceflight, but 2018 will be even more exciting, starting with Falcon Heavy first launch in the next month. #NSRC2017
https://twitter.com/jeff_foust/status/943135747477065728 (https://twitter.com/jeff_foust/status/943135747477065728)

FH before Zuma?
In the same month around the same time as Zuma is now on SLC-40, but FH launch date is dependent solely on FH pad testing and static fires before a date is set. It depends if FH has teething issues or not.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 12/19/2017 08:08 PM
FH before Zuma?

Not a chance (unless Zuma gets another big delay).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 12/20/2017 12:10 AM
Quote
Nield: 2017 has been pretty exciting for commercial spaceflight, but 2018 will be even more exciting, starting with Falcon Heavy first launch in the next month. #NSRC2017
https://twitter.com/jeff_foust/status/943135747477065728 (https://twitter.com/jeff_foust/status/943135747477065728)

FH before Zuma?

I think you're misreading the (somewhat ambiguous) tweet.  Nield was saying that the debut launch of the Falcon Heavy is currently planned to happen next month (January).  Not that the FH launch will be the first launch of that month. So, no.  Zuma will very likely be first.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: MATTBLAK on 12/20/2017 09:06 AM
There's something in my eye... :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: 0x32 on 12/20/2017 09:10 AM
Well, there it is, in all its glory. From Elon's Twitter.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jimbowman on 12/20/2017 09:10 AM
What is the ice from inside the nozzles? Or is that just soot from when they tested the stages?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/20/2017 09:11 AM
Larger versions

Note that the overhead view was photoshopped, a composite of at least two frames, possibly 3. The interstage is too short and it's missing the obvious stage separation pusher that's visible above the FH logo in the other shot.

I guess they couldn't capture the entire vehicle from overhead in a single frame without gross fisheye distortion so they had to mosaic separate frames with significantly different perspective.

Anyway, nice to finally see the mated hardware, the cores are actually a bit closer together than I imagined them to be due to the leg spacing, etc.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/20/2017 09:12 AM
What is the ice from inside the nozzles?

The consensus seems to be that it might be TEA/TEB residue from previous firings.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jimbowman on 12/20/2017 09:14 AM

The consensus seems to be that it might be TEA/TEB residue from previous firings.

Gotcha. Looked like icicles as first before I opened the higher res pictures. They would have had the hanger A/C on pretty low for that. Haha.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FutureSpaceTourist on 12/20/2017 09:17 AM
Can I just say how beautiful FH is?

Looks like titanium grid fins on the side boosters but aluminium on the central core.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: octavo on 12/20/2017 09:18 AM
Can I just say how beautiful FH is?

Looks like titanium grid fins on the side boosters but aluminium on the central core.
Lol, ninja'd. Yes and lots of pusher hardware on display.

It seems odd to be using such old hardware on a maiden flight. It's so incongruous to how space flight normally works, that my mind struggles with it.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/20/2017 09:19 AM
Interesting the side boosters have Ti grid fins while the centre core has Al fins. I would have assumed the other way round as the centre core has the hotter reentry.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jebbo on 12/20/2017 09:28 AM
Interesting that the two side boosters seem to be different ways up ...

--- Tony
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vanoord on 12/20/2017 09:37 AM
Interesting that the two side boosters seem to be different ways up ...

--- Tony

The two side cores are identical, ie the attachment points are at the same point on the radius of the octaweb - hence when attached to the centre core, they will be "different ways up".

From a point of view of ease of manufacture they only need to build one type of side core and presumably the only difference is to upload software that tells the core whether it's port or starboard (which they'd have to do if they built different 'handed' cores anyway).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jebbo on 12/20/2017 09:43 AM
The two side cores are identical, ie the attachment points are at the same point on the radius of the octaweb - hence when attached to the centre core, they will be "different ways up".

Thanks.  Makes sense ... i just hadn't thought about it before

--- Tony
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vanoord on 12/20/2017 09:44 AM
That, incidentally, puts to bed the debate as to whether the FH stack is assembled on the floor / whether the cranes are insufficient to lift an assembled stack onto the TEL / whether the stack is assembled on the TEL.

It's an impressive-looking beast, particularly at the business end.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Req on 12/20/2017 09:48 AM
https://twitter.com/elonmusk/status/943420026593337344

@elonmusk
Falcon Heavy at the Cape
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Cheapchips on 12/20/2017 10:11 AM
The titanium fins are bigger, so they felt they needed more control authority on the side boosters?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: loki on 12/20/2017 10:26 AM
Quite impressive as expected. Can’t wait for launch.
I guess Spacex needs this demo asap,  because design of busters has to be verified before starting production of Block5?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: eweilow on 12/20/2017 10:29 AM
https://twitter.com/elonmusk/status/943420026593337344

@elonmusk
Falcon Heavy at the Cape
It's worth noting that the first of the pictures (the one from above) is obviously a stitch of more than one picture and has resulted in some missing features just above the Falcon Heavy logo (like the separation pushers, which are clearly visible in the second picture) :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/20/2017 10:38 AM
The titanium fins are bigger, so they felt the needed more control authority on the side boosters?

Yes.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/20/2017 10:41 AM
https://twitter.com/elonmusk/status/943420026593337344

@elonmusk
Falcon Heavy at the Cape
It's worth noting that the first of the pictures (the one from above) is obviously a stitch of more than one picture and has resulted in some missing features just above the Falcon Heavy logo (like the separation pushers, which are clearly visible in the second picture) :)

http://forum.nasaspaceflight.com/index.php?topic=42705.msg1761564#msg1761564
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jet Black on 12/20/2017 10:45 AM
I'm curious as to why the outer cores have Ti grid fins rather than the Al of the center core. Could that be because the outer cores will be released lower in the atmosphere and need more control, since they will be relatively close together and have to redirect more quickly while performing a more complex maneuver (RTLS, boost back etc) than the center core, which will just go out to an ASDS somewhere out at sea?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/20/2017 10:51 AM
The large fins are due to increased control authority, but not for the purposes of clean separation of the two side boosters. At that point they are in effective vacuum and, besides, the fins are stowed during the most critical separation period.

Not sure what is public knowledge about this so I'll just say L2 has more info on this.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Skylab on 12/20/2017 11:47 AM
The large frame connecting the boosters surprised me. Guess I was just going by the early renderings, but it's quite big.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: JamesH65 on 12/20/2017 12:09 PM
I'm curious as to why the outer cores have Ti grid fins rather than the Al of the center core. Could that be because the outer cores will be released lower in the atmosphere and need more control, since they will be relatively close together and have to redirect more quickly while performing a more complex maneuver (RTLS, boost back etc) than the center core, which will just go out to an ASDS somewhere out at sea?

I wonder if they need the extra control to move the boosters further apart during reentry, perhaps to increase the time between each landing by one running an S shape return, one being straight.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IntoTheVoid on 12/20/2017 12:10 PM
https://twitter.com/elonmusk/status/943420026593337344

@elonmusk
Falcon Heavy at the Cape
It's worth noting that the first of the pictures (the one from above) is obviously a stitch of more than one picture and has resulted in some missing features just above the Falcon Heavy logo (like the separation pushers, which are clearly visible in the second picture) :)

If at the side of the picture, you look at the perspective of the steel ribs of the HIF, it seems pretty clear that it's 3 photos; one centered on the second stage, one centered at the grid fins, and one centered on the landing legs.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 12/20/2017 12:11 PM
The large frame connecting the boosters surprised me. Guess I was just going by the early renderings, but it's quite big.

The big frame at the top is very close to what was shown in renders two years ago.
What those renders from 2 years ago didn't show was the connections at the bottom.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/20/2017 12:40 PM
What those renders from 2 years ago didn't show was the connections at the bottom.

Including the missing TSMs, heh.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Skylab on 12/20/2017 12:47 PM
Two years is the blink of an eye in Falcon Heavy terms. ;) Glad to finally be on the eve of seeing the first launch.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 12/20/2017 01:44 PM
Larger versions
This is perhaps the most magnificent post in a long time
(with honorable mentions for the posts of the same photos in lower resolution)
Can anyone make out any details other than the grid fins?
Anything special about the PAF which can only be partly seen?
(No Roadster but that will be encapsulated before being attached.  Boo hoo)
The attach mechanisms all seem to be held dynamically against the launch forces. Not what I expected.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Nomadd on 12/20/2017 01:50 PM
Interesting the side boosters have Ti grid fins while the centre core has Al fins. I would have assumed the other way round as the centre core has the hotter reentry.

No interstage on the sides, so they need the bigger fins because of the airflow.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 12/20/2017 02:37 PM
Anything special about the PAF which can only be partly seen?

The PAF isn’t even present, that’ll be with the payload wherever it’s being processed. The top of the second stage is the avionics tower.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/20/2017 02:40 PM
I wonder if they are production-constrained on the Ti fins?  It was discussed here (tea-leaf-reading on some ambiguous tweets from Elon) that perhaps the first prototype Ti fins were machined from a solid block while the production fins would be forged, and that the forging process had significant setup costs/lead time, so they might not want to get that going until the Ti fin design had been thoroughly vetted... presumably including on this FH maiden flight.

So there might be only two sets of prototype Ti fins in existence, and they've been dedicated to the two FH side boosters... explaining why some other recent high-energy F9 flight candidates haven't opted for Ti.

For that matter, they obviously see no reason *not* to use Al fins, like on the center booster here, so Al not be end-of-lifed with F9 block 5.  Put another way, the only "problem" with Al fins is limited reusability, not functionality (for F9; FH needs the extra control).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: matthewkantar on 12/20/2017 02:54 PM
Nice detail.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: StevenV on 12/20/2017 03:00 PM
The center core also has no use for the greater cross-range the titanium fins give.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 12/20/2017 03:16 PM
I wonder if they are production-constrained on the Ti fins?  It was discussed here (tea-leaf-reading on some ambiguous tweets from Elon) that perhaps the first prototype Ti fins were machined from a solid block while the production fins would be forged, and that the forging process had significant setup costs/lead time, so they might not want to get that going until the Ti fin design had been thoroughly vetted... presumably including on this FH maiden flight.

So there might be only two sets of prototype Ti fins in existence, and they've been dedicated to the two FH side boosters... explaining why some other recent high-energy F9 flight candidates haven't opted for Ti.

For that matter, they obviously see no reason *not* to use Al fins, like on the center booster here, so Al not be end-of-lifed with F9 block 5.  Put another way, the only "problem" with Al fins is limited reusability, not functionality (for F9; FH needs the extra control).
They may 3D print the fins in the future if they want to pursue maximum achievable strength, quality, reduced lead and manpower times and cost reduction.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/20/2017 03:19 PM
It has been mentioned by Elon they they will be forged. The biggest Ti forgings ever.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/20/2017 03:25 PM
Elon has tweeted forged as well as machined at various times.  (He's never mentioned printed.) Let's please not reopen that debate.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/20/2017 03:29 PM
I just noticed that the white gunk/residue inside the nozzles actually contains markings on some engines. The right side booster has two nozzles marked "6" and "8", although that would make them clocked the opposite way of what the F9 user guide shows. The left side booster also appears to contain the number 8 in the expected location, considering the two cores are 180 deg apart.

Edit: nvm, it's the same clockwise direction.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 12/20/2017 03:44 PM
Larger versions

Note that the overhead view was photoshopped, a composite of at least two frames, possibly 3. The interstage is too short and it's missing the obvious stage separation pusher that's visible above the FH logo in the other shot.

I guess they couldn't capture the entire vehicle from overhead in a single frame without gross fisheye distortion so they had to mosaic separate frames with significantly different perspective.

Anyway, nice to finally see the mated hardware, the cores are actually a bit closer together than I imagined them to be due to the leg spacing, etc.

Not to mention that operator looking up (twice), next to the yellow command cord...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: pb2000 on 12/20/2017 05:11 PM
I'm sure this has been asked multiple times in the past, but what's with the strap holding up the center engines? I've seen it before on recovered cores being transferred back to the HIF, but not during rollout prep.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: matthewkantar on 12/20/2017 05:28 PM
I'm sure this has been asked multiple times in the past, but what's with the strap holding up the center engines? I've seen it before on recovered cores being transferred back to the HIF, but not during rollout prep.

Just a guess: the center engine may have a different gimbal than the outsiders, needs a little help to stabilize it while moving. For instance the outside engines are more accessible, or more easily lockable than the center.

Matthew
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: the_other_Doug on 12/20/2017 05:33 PM
I have a question about the upper attach structure.  I doubt we will know for certain how it is planned to work until we see the flight, but here goes:

In the detail below, it would appear that the cross-struts that attach tangentially across the center core cannot remain on the center core -- at least where they are right now -- and still allow its grid fins to deploy and have full freedom of movement.  But I would suspect the same thing of the side cores, were these struts to separate in the middle and depart with the side cores.

Do they actually fold up along the side of the interstage on the center core?  Do they stay with the side cores, giving them uneven airflow and thus requiring the additional control authority of the larger titanium grid fins?  Or are they simply jettisoned at some point, a small amount of hardware given up to the rocket equation gods?

Sorry if this has been discussed in detail elsewhere and I have missed it.  It's not humanly possible to read every post in this forum and still maintain heavy life responsibilities... sigh...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/20/2017 05:36 PM
I have a question about the upper attach structure.  I doubt we will know for certain how it is planned to work until we see the flight, but here goes:

In the detail below, it would appear that the cross-struts that attach tangentially across the center core cannot remain on the center core -- at least where they are right now -- and still allow its grid fins to deploy and have full freedom of movement.  But I would suspect the same thing of the side cores, were these struts to separate in the middle and depart with the side cores.

Do they actually fold up along the side of the interstage on the center core?  Do they stay with the side cores, giving them uneven airflow and thus requiring the additional control authority of the larger titanium grid fins?  Or are they simply jettisoned at some point, a small amount of hardware given up to the rocket equation gods?

Sorry if this has been discussed in detail elsewhere and I have missed it.  It's not humanly possible to read every post in this forum and still maintain heavy life responsibilities... sigh...
They fold up per the animation
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 12/20/2017 05:40 PM
I have a question about the upper attach structure.  I doubt we will know for certain how it is planned to work until we see the flight, but here goes:

In the detail below, it would appear that the cross-struts that attach tangentially across the center core cannot remain on the center core -- at least where they are right now -- and still allow its grid fins to deploy and have full freedom of movement.  But I would suspect the same thing of the side cores, were these struts to separate in the middle and depart with the side cores.

Do they actually fold up along the side of the interstage on the center core?  Do they stay with the side cores, giving them uneven airflow and thus requiring the additional control authority of the larger titanium grid fins?  Or are they simply jettisoned at some point, a small amount of hardware given up to the rocket equation gods?

Sorry if this has been discussed in detail elsewhere and I have missed it.  It's not humanly possible to read every post in this forum and still maintain heavy life responsibilities... sigh...

I seem to recall seeing the answer to this but I can't recall where. So this is phrased as a guess. I am guessing that the two arms remain attached to the center stage. They pivot downward at hinge points that are not very far from the center point of the center core. This pivot gives the clearance necessary for the center stage grid fins to do their thing. Since they stay attached to the center stage, they have no effect on the side core grid fins post separation.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/20/2017 05:45 PM
They remain on the center core and pivot upward. You can see the latches just above the US flag.

https://www.youtube.com/watch?v=4Ca6x4QbpoM
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: the_other_Doug on 12/20/2017 05:55 PM
They remain on the center core and pivot upward. You can see the latches just above the US flag.

Thanks.  I thought those lumps up on the interstage looked like latch points.  And yeah, I recall what the original CGI showed, but the SpaceX CGIs have not always been accurate, especially after several intervening years of design-fiddling.

I will be quite impressed with a strut system that has a hinge right where it encounters the greatest stress.  When I see it fly, that is.  It just seems counter-intuitive to place a hinge right at that extremely high-tension-stress location on the stack.  I thought the folding struts were a CGI flight of fancy and expected a rigid structure of some kind would replace the kewl folding struts, to be honest.

I shouldn't have asked about this prior to the flight.  Now I'll worry about it from liftoff all the way through side core sep... :(
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/20/2017 06:00 PM
Maybe there is a beam that goes through the hinge that takes the load and is retracted after sep to allow the hinge to fold, who knows? I think there will be a lot of people worrying/watching with popcorn all though this launch!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: biosehnsucht on 12/20/2017 06:14 PM
Someone on reddit (https://www.reddit.com/r/spacex/comments/7l0fi9/falcon_heavy_at_cape/dringaq/) pointed out what might be stitching errors or some kind of intentional editing.

https://i.imgur.com/PQSPi2z.png

These details along the raceway are lined up in one image, but not in the other. I'm guessing someone was just not paying attention when it came time to stitch, or left it to automated software and it got confused.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: sevenperforce on 12/20/2017 06:29 PM
I have a question about the upper attach structure.  I doubt we will know for certain how it is planned to work until we see the flight, but here goes:

In the detail below, it would appear that the cross-struts that attach tangentially across the center core cannot remain on the center core -- at least where they are right now -- and still allow its grid fins to deploy and have full freedom of movement.  But I would suspect the same thing of the side cores, were these struts to separate in the middle and depart with the side cores.

Do they actually fold up along the side of the interstage on the center core?  Do they stay with the side cores, giving them uneven airflow and thus requiring the additional control authority of the larger titanium grid fins?  Or are they simply jettisoned at some point, a small amount of hardware given up to the rocket equation gods?

Sorry if this has been discussed in detail elsewhere and I have missed it.  It's not humanly possible to read every post in this forum and still maintain heavy life responsibilities... sigh...
They are hinged at the attachment point on the core and fold up. If you look very closely, you can see that the slightly angled rods/arms above the cross-struts (attached to them at the center) have a narrow section and a wide section; those are hydraulic pistons that will retract, pulling the cross-struts up against the core, where they latch into the attachment manifold right above the flag.

I will be quite impressed with a strut system that has a hinge right where it encounters the greatest stress.  When I see it fly, that is.  It just seems counter-intuitive to place a hinge right at that extremely high-tension-stress location on the stack.  I thought the folding struts were a CGI flight of fancy and expected a rigid structure of some kind would replace the kewl folding struts, to be honest.
I'd assume the primary vector for force transfer is at the pair of lower clasps holding the three octawebs together. These struts are likely just to prevent differential yaw/pitch, not to transfer force from the side boosters to the core.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 12/20/2017 06:47 PM
They remain on the center core and pivot upward. You can see the latches just above the US flag.

Thanks.  I thought those lumps up on the interstage looked like latch points.  And yeah, I recall what the original CGI showed, but the SpaceX CGIs have not always been accurate, especially after several intervening years of design-fiddling.

I will be quite impressed with a strut system that has a hinge right where it encounters the greatest stress.  When I see it fly, that is.  It just seems counter-intuitive to place a hinge right at that extremely high-tension-stress location on the stack.  I thought the folding struts were a CGI flight of fancy and expected a rigid structure of some kind would replace the kewl folding struts, to be honest.

I shouldn't have asked about this prior to the flight.  Now I'll worry about it from liftoff all the way through side core sep... :(

In a good truss system, the individual struts are always hinged, or assumed to be hinged, so do not transfer any torques.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: the_other_Doug on 12/20/2017 06:51 PM
I'd assume the primary vector for force transfer is at the pair of lower clasps holding the three octawebs together. These struts are likely just to prevent differential yaw/pitch, not to transfer force from the side boosters to the core.

Interesting.  I had always heard that the Shuttle's intertank structure had to be so heavily built was because the upper attach points were where the thrust actually transferred into the stack.  On the Shuttle stack, anyway, most of the thrust transfer happened up top, not down below.  I also recall reading the same comment about the SRB connections on the Titan III and IV family.

Granted, my memory fails me more often than it used to.  But I guess I had been assuming that this was a generic feature of most side-mounted booster systems, and that the upper attach points would be carrying the majority of the load into the stack.  Of course, on a lot of those configs, the lower attach point wasn't, as it is on FH, located roughly where the engine thrust was being transferred to each individual core -- in fact, a lot of those configs had quite different planes along the stack height where thrust transferred into the individual cores.  Perhaps that impacts the stability of using the lower attach points for primary thrust transfer into the stack.

One thing I do know, and that is that a lot of people with engineering degrees have been working on this for years.  If their analyses said the was no problem with the amount of stress being put through a hinge -- no matter how well the main strut is cross-loaded -- then my far less informed worries are probably just that: uninformed worries.

;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Archibald on 12/20/2017 06:52 PM
Saw the pictures on Parabolic arc. And here. what an amazing rocket. Hopefully it won't fire while laying horizontal in the hangar.
Now it only lacks the roadster and fairing. Boom and zoom, onto Mars with Space Oddity.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RoboGoofers on 12/20/2017 07:13 PM
I have a question about the upper attach structure.  I doubt we will know for certain how it is planned to work until we see the flight, but here goes:

In the detail below, it would appear that the cross-struts that attach tangentially across the center core cannot remain on the center core -- at least where they are right now -- and still allow its grid fins to deploy and have full freedom of movement.  But I would suspect the same thing of the side cores, were these struts to separate in the middle and depart with the side cores.

Do they actually fold up along the side of the interstage on the center core?  Do they stay with the side cores, giving them uneven airflow and thus requiring the additional control authority of the larger titanium grid fins?  Or are they simply jettisoned at some point, a small amount of hardware given up to the rocket equation gods?

Sorry if this has been discussed in detail elsewhere and I have missed it.  It's not humanly possible to read every post in this forum and still maintain heavy life responsibilities... sigh...
They are hinged at the attachment point on the core and fold up. If you look very closely, you can see that the slightly angled rods/arms above the cross-struts (attached to them at the center) have a narrow section and a wide section; those are hydraulic pistons that will retract, pulling the cross-struts up against the core, where they latch into the attachment manifold right above the flag.

Are you talking about the yellow saddle piece?  Because i'm wondering where it and the struts it's attached to go.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: groknull on 12/20/2017 07:31 PM
I have a question about the upper attach structure.  I doubt we will know for certain how it is planned to work until we see the flight, but here goes:

In the detail below, it would appear that the cross-struts that attach tangentially across the center core cannot remain on the center core -- at least where they are right now -- and still allow its grid fins to deploy and have full freedom of movement.  But I would suspect the same thing of the side cores, were these struts to separate in the middle and depart with the side cores.

Do they actually fold up along the side of the interstage on the center core?  Do they stay with the side cores, giving them uneven airflow and thus requiring the additional control authority of the larger titanium grid fins?  Or are they simply jettisoned at some point, a small amount of hardware given up to the rocket equation gods?

Sorry if this has been discussed in detail elsewhere and I have missed it.  It's not humanly possible to read every post in this forum and still maintain heavy life responsibilities... sigh...
They are hinged at the attachment point on the core and fold up. If you look very closely, you can see that the slightly angled rods/arms above the cross-struts (attached to them at the center) have a narrow section and a wide section; those are hydraulic pistons that will retract, pulling the cross-struts up against the core, where they latch into the attachment manifold right above the flag.

Are you talking about the yellow saddle piece?  Because i'm wondering where it and the struts it's attached to go.

Conjecture:

Yellow saddle pieces do not fly*.  Diagonal struts (between the tangential ones) from side stages to the center stage stay with the side stages.  Possibly pull out of sockets on the center stage (fat section under tangential struts), then fold up against the side booster nose cone.  There is a small fairing on the inboard side of each side booster nose cone that might be a latch point**.

Edit: * may be an assembly jig or strap; ** or a vent, or more likely, a camera port.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Coastal Ron on 12/20/2017 07:41 PM
The left side booster also appears to contain the number 8 in the expected location, considering the two cores are 180 deg apart.

Actually the two side boosters are not 180 degrees apart. I noticed the feed line that runs down the side of the boosters are installed so that they are on the same side of the center stage.

Speculation: Having both on one side provides consistent lift characteristics? For instance, if the "bottom" of the stage in flight is the side with the feed lines, then the flat area of the feed lines may provide some level of aerodynamic lift when compared with a side that does not have feed lines.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 12/20/2017 07:45 PM
The left side booster also appears to contain the number 8 in the expected location, considering the two cores are 180 deg apart.

Actually the two side boosters are not 180 degrees apart. I noticed the feed line that runs down the side of the boosters are installed so that they are on the same side of the center stage.

What precisely do you mean by feed lines? To the best that my eye can see, they are identical cores, one simply rotated 180 degrees. Like Atlas V HLV would have done and unlike Delta IV Heavy.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/20/2017 07:47 PM
The left side booster also appears to contain the number 8 in the expected location, considering the two cores are 180 deg apart.

Actually the two side boosters are not 180 degrees apart. I noticed the feed line that runs down the side of the boosters are installed so that they are on the same side of the center stage.

Speculation: Having both on one side provides consistent lift characteristics? For instance, if the "bottom" of the stage in flight is the side with the feed lines, then the flat area of the feed lines may provide some level of aerodynamic lift when compared with a side that does not have feed lines.

Are you seeing some other image than we are??  :o It is clear that one side booster is matches the rotation of the core, but the other one is rotated 180 degrees. Just look at the big racetrack piping on the right core.

You can also see the rotation in the engine view, by noting the color of the propellant attachments. Blue or Red. (for LOX or RP1)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: docmordrid on 12/20/2017 08:22 PM
Elon Musk ✔ @elonmusk
Max thrust at lift-off is 5.1 million pounds or 2300 metric tons. First mission will run at 92%.
4:13 PM - Dec 20, 2017

https://twitter.com/elonmusk/status/943590152181448704
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: sevenperforce on 12/20/2017 08:36 PM
They are hinged at the attachment point on the core and fold up. If you look very closely, you can see that the slightly angled rods/arms above the cross-struts (attached to them at the center) have a narrow section and a wide section; those are hydraulic pistons that will retract, pulling the cross-struts up against the core, where they latch into the attachment manifold right above the flag.

Are you talking about the yellow saddle piece?  Because i'm wondering where it and the struts it's attached to go.
No, I'm talking about the white connector arms that are just barely angled and are attached at the center of those struts.

The piston is pulled into the sheath via hydraulics, which rotates the strut up.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/20/2017 08:58 PM
Yellow saddle piece is part of the pusher mechanism to separate the boosters, I think. (Although I agree that the yellow piece itself will probably not fly.)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/20/2017 09:00 PM
Someone on reddit (https://www.reddit.com/r/spacex/comments/7l0fi9/falcon_heavy_at_cape/dringaq/) pointed out what might be stitching errors or some kind of intentional editing.

https://i.imgur.com/PQSPi2z.png

These details along the raceway are lined up in one image, but not in the other. I'm guessing someone was just not paying attention when it came time to stitch, or left it to automated software and it got confused.
Yes, discussed earlier.  On the right on the uncropped version you can see the guy holding the yellow cable to trigger the camera... twice.  Consensus here was that there are three images stitched together; you can actually see the yellow command cord a third time at the bottom, but the photographer themself has been stitched away.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/20/2017 09:05 PM
Someone on reddit (https://www.reddit.com/r/spacex/comments/7l0fi9/falcon_heavy_at_cape/dringaq/) pointed out what might be stitching errors or some kind of intentional editing.

https://i.imgur.com/PQSPi2z.png

These details along the raceway are lined up in one image, but not in the other. I'm guessing someone was just not paying attention when it came time to stitch, or left it to automated software and it got confused.
Yes, discussed earlier.  On the right on the uncropped version you can see the guy holding the yellow cable to trigger the camera... twice.  Consensus here was that there are three images stitched together; you can actually see the yellow command cord a third time at the bottom, but the photographer themself has been stitched away.

The sep nodes for the second stage on the interstage are missing too
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: sevenperforce on 12/20/2017 09:59 PM
Quote
Max thrust at lift-off is 5.1 million pounds or 2300 metric tons. First mission will run at 92%.

https://twitter.com/elonmusk/status/943590152181448704

Quote
Falcon Heavy launching from same @NASA pad as the Saturn V Apollo 11 moon rocket. It was 50% higher thrust with five F-1 engines at 7.5M lb-F. I love that rocket so much.

https://twitter.com/elonmusk/status/943592480926076928
Just add one core to the front of the core, another to the back, rotate 45 degrees, and redo the launch mount/reaction frame?  ;)
Nine Merlin 1Ds have just 12% more thrust than a single F1.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Zed_Noir on 12/20/2017 10:09 PM
Quote
Max thrust at lift-off is 5.1 million pounds or 2300 metric tons. First mission will run at 92%.

https://twitter.com/elonmusk/status/943590152181448704

Quote
Falcon Heavy launching from same @NASA pad as the Saturn V Apollo 11 moon rocket. It was 50% higher thrust with five F-1 engines at 7.5M lb-F. I love that rocket so much.

https://twitter.com/elonmusk/status/943592480926076928
Just add one core to the front of the core, another to the back, rotate 45 degrees, and redo the launch mount/reaction frame?  ;)

Yes, but think it will be easier to assemble you quint core LV on a new customized MLP inside the VAB and launch from LC_39B.

Of course that requires a new reinforced center core that can handle the stress of 4 strapped-on booster cores.

The Falcon Heavy should go with a new Raptor upper stage for increase performance instead of more cores. It will take less money and time. ;)


Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/20/2017 10:46 PM
Well, there it is, in all its glory. From Elon's Twitter.
Welcome to the forum and spectacular first post!! 8)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/20/2017 10:49 PM
Can I just say how beautiful FH is?

Looks like titanium grid fins on the side boosters but aluminium on the central core.
Lol, ninja'd. Yes and lots of pusher hardware on display.

It seems odd to be using such old hardware on a maiden flight. It's so incongruous to how space flight normally works, that my mind struggles with it.
I like to use the word "proven" instead of "old" hardware... ;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: MATTBLAK on 12/21/2017 01:26 AM
Possibly belongs in a cheerleading thread; but I reckon there's only one piece of music to dub to first (successful) flight footage of this monster... 

https://www.youtube.com/watch?v=rFF41xB6KII
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: TripD on 12/21/2017 01:42 AM
Tweaked to bring out more details.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: sevenperforce on 12/21/2017 01:50 AM
I wonder if the fairing will come off after booster sep but before core staging.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 12/21/2017 01:54 AM
A video with a view from the outside looking into the hangar (though unfortunately with bad window glare).

https://www.instagram.com/p/Bc7fyjWFPjB/


Edit: This was from earlier this week.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 12/21/2017 01:59 AM
I wonder if the fairing will come off after booster sep but before core staging.

That's a possibility, but then again, fairing sep could occur after second stage engine start; just like the Delta IV Heavy.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 12/21/2017 02:12 AM
A video with a view from the outside looking into the hangar (though unfortunately with bad window glare).

https://www.instagram.com/p/Bc7fyjWFPjB/

The Zuma booster and upper stage are still on the transporter in the HIF, and the RSS legs are still up in that video so it's at least a day or two old.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vaporcobra on 12/21/2017 03:22 AM
A video with a view from the outside looking into the hangar (though unfortunately with bad window glare).

https://www.instagram.com/p/Bc7fyjWFPjB/

It's probably obvious to anyone who clicks on the link, but fair warning that this video is from last Friday, just before 1043 was moved.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rangertech1 on 12/21/2017 05:03 AM
Quote
Max thrust at lift-off is 5.1 million pounds or 2300 metric tons. First mission will run at 92%.

https://twitter.com/elonmusk/status/943590152181448704

Quote
Falcon Heavy launching from same @NASA pad as the Saturn V Apollo 11 moon rocket. It was 50% higher thrust with five F-1 engines at 7.5M lb-F. I love that rocket so much.

https://twitter.com/elonmusk/status/943592480926076928
Just add one core to the front of the core, another to the back, rotate 45 degrees, and redo the launch mount/reaction frame?  ;)

Yes, but think it will be easier to assemble you quint core LV on a new customized MLP inside the VAB and launch from LC_39B.

Of course that requires a new reinforced center core that can handle the stress of 4 strapped-on booster cores.

The Falcon Heavy should go with a new Raptor upper stage for increase performance instead of more cores. It will take less money and time. ;)

But you don't get to mine the diamonds that are created in the flame trench after that "quint" core abomination leaves the pad. :-X
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: MATTBLAK on 12/21/2017 11:03 AM
Possibly belongs in a cheerleading thread; but I reckon there's only one piece of music to dub to first (successful) flight footage of this monster... 

https://www.youtube.com/watch?v=rFF41xB6KII
Heh; I did a dub of the music onto the standard SpaceX animation. I think it almost works...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/21/2017 12:40 PM
A bit of a tease but sounds like payload is either in processing or encapsulated:

Can confirm that it is already mated to the payload adapter.

Can you confirm whether or not this was it:

I was taking a sponsored community college kid on a bus tour at KSC a few days back on the 8th.
We got stopped by the escort vehicles for... this.
Headed to 39A as far as I could tell...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Norm38 on 12/21/2017 01:43 PM
Did they change the Ti grid fin design?  I don't see the scalloped edges in the latest FH images.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: matthewkantar on 12/21/2017 01:58 PM
Did they change the Ti grid fin design?  I don't see the scalloped edges in the latest FH images.

The two outer cores are fitted with TI grid fins, the center core has Al fins.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/21/2017 01:59 PM
Did they change the Ti grid fin design?  I don't see the scalloped edges in the latest FH images.

I think it's there, the scalloped side is the side against the stage so hard to see.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Coastal Ron on 12/21/2017 08:44 PM
The left side booster also appears to contain the number 8 in the expected location, considering the two cores are 180 deg apart.

Actually the two side boosters are not 180 degrees apart. I noticed the feed line that runs down the side of the boosters are installed so that they are on the same side of the center stage.

What precisely do you mean by feed lines? To the best that my eye can see, they are identical cores, one simply rotated 180 degrees. Like Atlas V HLV would have done and unlike Delta IV Heavy.

OK, apparently it was an optical delusion on my part. I mistook the underside of the legs for the external "structure" that runs down the side of each 1st stage (what I called feed lines, but not sure now). The wide angle of the camera lens meant that you don't see the other legs easily, which added to my confusion.

Nothing to see here...  :o
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: abaddon on 12/21/2017 09:57 PM
Been meaning to ask a (rather trivial) question but keep forgetting: does anyone know why some (but not all) of the engine bells on the left booster are shiny/reflective, while all the other engine bells are matte/sooty?  Any significance to that?

(Best seen from the overhead views)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jcc on 12/21/2017 11:32 PM
Did they change the Ti grid fin design?  I don't see the scalloped edges in the latest FH images.

The two outer cores are fitted with TI grid fins, the center core has Al fins.

I find that a bit odd, I would think that the center core would be higher energy than the side boosters.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/21/2017 11:36 PM
Due to the turbulence produced by the nose cone of the side boosters while it is traveling backwards more control authority is needed by the side booster than the centre stage. Hence they have the larger Ti grid fins.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 12/21/2017 11:58 PM
Due to the turbulence produced by the nose cone of the side boosters while it is traveling backwards more control authority is needed by the side booster than the centre stage. Hence they have the larger Ti grid fins.

And/or they want more authority during separation (and forward flight) to ensure control of the separating stages.

If they can get the cores to "peel" using the grid fins, beyond a certain angle, the force on the entire body of the side boosters will point outwards and thus be safe.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/22/2017 12:04 AM
The separation is performed in vacuum, grid fins can't help then.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 12/22/2017 07:14 AM
Been meaning to ask a (rather trivial) question but keep forgetting: does anyone know why some (but not all) of the engine bells on the left booster are shiny/reflective, while all the other engine bells are matte/sooty?  Any significance to that?

(Best seen from the overhead views)

SpaceX stopped shining the nozzles at some point and switched to a matte finish.  Since they are reusing old boosters, the full switch must have happened between the original launch dates for the side cores.  Before they went to all engines on a booster matte, they experimented with a mix of both.  Well, first I think they experimented with a few only partially shined bells (they looked like they had stripes running up and down), then went forward incrementally from there.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 12/22/2017 11:56 AM
The separation is performed in vacuum, grid fins can't help then.
That would indeed be a problem..  but how high are we talking about?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/22/2017 12:05 PM
Around 100km, I've attached below a brilliant bit of visualization from redditor veebay that shows a detailed Falcon 9 Stage 1 Landing Analysis (https://www.reddit.com/r/spacex/comments/7ajf09/falcon_9_stage_1_landing_analysis/). It's really good so I hope attaching it here is ok, if not follow the link. In fact follow the link anyway and check it out.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Norm38 on 12/22/2017 01:39 PM
Due to the turbulence produced by the nose cone of the side boosters while it is traveling backwards more control authority is needed by the side booster than the centre stage. Hence they have the larger Ti grid fins.

This I can't picture. The tails of aircraft aren't open cylinders, they taper to points.
I get that the two are different and have different control responses. But why does the nosecone produce
worse turbulence? Is it not long enough or something?

Edit:  I guess this belongs in an FH thread.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: wolfpack on 12/22/2017 01:53 PM
What do we think the biggest risks are for this mission? If I had to guess, in order:

1. Side booster sep
2. Liftoff
3. MaxQ
4. Faring sep
5. S/C sep

Anyone else?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/22/2017 02:32 PM
Due to the turbulence produced by the nose cone of the side boosters while it is traveling backwards more control authority is needed by the side booster than the centre stage. Hence they have the larger Ti grid fins.

This I can't picture. The tails of aircraft aren't open cylinders, they taper to points.
I get that the two are different and have different control responses. But why does the nosecone produce
worse turbulence? Is it not long enough or something?

Edit:  I guess this belongs in an FH thread.

It probably should be in the FH thread and there is a discussion in the L2 version but you asked the question here so...

You guessed the answer, the nose cone isn't long enough, or rather it's not designed to fly backwards but it is the right shape for assent which is more important. For some reason the booster with the interstage still attached is fine. So you could make it fit this thread by asking why doesn't the booster need larger fins as it flies today?

https://www.youtube.com/watch?v=IPBKR9cSce0
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: drnscr on 12/22/2017 02:32 PM
What do we think the biggest risks are for this mission? If I had to guess, in order:

1. Side booster sep
2. Liftoff
3. MaxQ
4. Faring sep
5. S/C sep

Anyone else?

So, in other words, everything except engine startup.  I have to put engine startup at the top of the list.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Xentry on 12/22/2017 02:46 PM
1. MaxQ
2. Engine Startup
3. Liftoff
4. Side booster sep
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Michael.Kalenty on 12/22/2017 02:49 PM
What do we think the biggest risks are for this mission? If I had to guess, in order:

1. Side booster sep
2. Liftoff
3. MaxQ
4. Faring sep
5. S/C sep

Anyone else?

Biggest risks will be anything different from Falcon 9 that they can't test on the ground. Those would be:
1. Booster sep
2. Ignition (The launch itself is just releasing the holddowns. Larger risk is the near-simultanious ignition of 27 engines.)
3. The entire ascent between liftoff and booster sep. (This portion of flight is a essnetially flying 3 rockets side by side, so the boosters run the risk of ripping away from the core, or the opposite)

Anything after booster sep (Core/S2 sep, fairing sep, S/C sep) is essentially identical to a Falcon 9 flight, so I'd rate the risk level of these events the same I would on a Falcon 9 mission.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: TaurusLittrow on 12/22/2017 02:57 PM
Any estimates of the time between the static fire of Falcon Heavy (assuming successful) and the initial launch attempt?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jarnis on 12/22/2017 02:59 PM
Any estimates of the time between the static fire of Falcon Heavy (assuming successful) and the initial launch attempt?

1-2 weeks would be my guess. Zuma is I think January 4th and I don't think they're fully equipped for two east coast teams, so I do not think they can launch before that. Might not even get a static fire before that.

...and the next east coast one after that is very late in January, so... somewhere in between those, assuming everything "just works". If they see any issues during WDR and/or static fire, all depends on how long the fixes take.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 12/22/2017 04:44 PM
Been meaning to ask a (rather trivial) question but keep forgetting: does anyone know why some (but not all) of the engine bells on the left booster are shiny/reflective, while all the other engine bells are matte/sooty?  Any significance to that?

(Best seen from the overhead views)

SpaceX stopped shining the nozzles at some point and switched to a matte finish.  Since they are reusing old boosters, the full switch must have happened between the original launch dates for the side cores.  Before they went to all engines on a booster matte, they experimented with a mix of both.  Well, first I think they experimented with a few only partially shined bells (they looked like they had stripes running up and down), then went forward incrementally from there.

I did some detective work last night while Abaddon's original post was the last one just sitting there for hours. First of all you can tell the shiny bells are not brand new replacements because the larger photo of the underside shows TEA/TEB trails inside every bell. Next, it's clear the shiny bells are on core 23 which was the Thaicom 8 booster, one of the earliest successful landings at #4 and the "Leaning Tower of Thaicom". Yes SpaceX was removing & replacing bells early on, adding ample opportunity to clean a few before a decision that cleaning the rest was unnecessary, or just to give an intern or someone with some downtime something to work on temporarily, but take your pick from a wealth of landing videos. It looks like those bells might have come in that clean, or cleaner enough to wipe down more easily than the others. My guess is the shiny bells were on the high side opposite the crushed leg and residual flaming, and the sooty exception inbetween them was part of the 1-3-1 landing burn.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 12/22/2017 04:47 PM
What do we think the biggest risks are for this mission? If I had to guess, in order:

1. Side booster sep
2. Liftoff
3. MaxQ
4. Faring sep
5. S/C sep

Anyone else?

So, in other words, everything except engine startup.  I have to put engine startup at the top of the list.

They will be testing that in the static fire, probably starting with a few engines and building up as they get some data. If it works there it's low risk for the launch.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 12/22/2017 05:22 PM
What do we think the biggest risks are for this mission? If I had to guess, in order:

1. Side booster sep
2. Liftoff
3. MaxQ
4. Faring sep
5. S/C sep

Anyone else?

So, in other words, everything except engine startup.  I have to put engine startup at the top of the list.

They will be testing that in the static fire, probably starting with a few engines and building up as they get some data. If it works there it's low risk for the launch.

From Chris Gebhardt's latest FH article dated Nov 1st at https://www.nasaspaceflight.com/2017/11/spacex-aims-december-launch-falcon-heavy/

Quote
Due to thrust torque (a thrust-induced rotation) scenario that could destroy or severely damage the octawebs at the base of each Falcon core that house the Merlin 1D engines, the Falcon Heavy’s 27 engines will not be lit simultaneously like the Falcon 9 engines. Instead, Falcon Heavy will take a page from the Space Shuttle’s book and will employ a staggered start sequence – like main engine start on Shuttle where each main engine started 120 milliseconds after the previous. For Falcon Heavy, it is understood that two engines will be lit simultaneously followed by the next two… and so on until all 27 are up and running.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Paul_G on 12/22/2017 05:25 PM
Due to the turbulence produced by the nose cone of the side boosters while it is traveling backwards more control authority is needed by the side booster than the centre stage. Hence they have the larger Ti grid fins.

This I can't picture. The tails of aircraft aren't open cylinders, they taper to points.
I get that the two are different and have different control responses. But why does the nosecone produce
worse turbulence? Is it not long enough or something?

Edit:  I guess this belongs in an FH thread.

My guess - the open cylinder of a standard F9 stage creates drag, that helps keeps the stage pointing the right way. The cone ends of the side boosters do not create so much drag, meaning the engine end could end up being more 'dragy' than the top of the stage. Larger grid find help create the drag to keep the side boosters facing the right way?

Paul
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cppetrie on 12/22/2017 06:02 PM
Due to the turbulence produced by the nose cone of the side boosters while it is traveling backwards more control authority is needed by the side booster than the centre stage. Hence they have the larger Ti grid fins.

This I can't picture. The tails of aircraft aren't open cylinders, they taper to points.
I get that the two are different and have different control responses. But why does the nosecone produce
worse turbulence? Is it not long enough or something?

Edit:  I guess this belongs in an FH thread.

My guess - the open cylinder of a standard F9 stage creates drag, that helps keeps the stage pointing the right way. The cone ends of the side boosters do not create so much drag, meaning the engine end could end up being more 'dragy' than the top of the stage. Larger grid find help create the drag to keep the side boosters facing the right way?

Paul
There was a fairly lengthy discussion in L2 when the design and size of the new grid fins was first discovered. I’m was not (and still am not) very knowledgeable on the topic so I found the explanation counterintuitive. My layman’s summary is that the grid fins require turbulent airflow through them to work. The open cylinder of the interstage creates said turbulent airflow. The smooth nose cone creates less turbulent flow and decreases the effectiveness of the grid fins, which is why the side boosters require larger ones with scalloped leading edges that result in greater control authority. I’ve probably oversimplified the explanation so if someone more knowledgeable wants to chime in go ahead, but that was my take away. It’s counterintuitive to me and the physics of ailerons and tails on the back end of a cone-shaped plane operating at subsonic speed aren’t applicable.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Norm38 on 12/22/2017 07:30 PM
That makes sense, but the post I responded to implied that the nosecones produce more turbulence, not less.
At least, that's how I read it.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 12/22/2017 09:43 PM
There was a fairly lengthy discussion in L2 when the design and size of the new grid fins were first discovered. I’m was not (and still am not) very knowledgeable on the topic so I found the explanation counterintuitive. My layman’s summary is that the grid fins require turbulent airflow through them to work. The open cylinder of the interstage creates said turbulent airflow. The smooth nose cone creates less turbulent flow and decreases the effectiveness of the grid fins, which is why the side boosters require larger ones with scalloped leading edges that result in greater control authority. I’ve probably oversimplified the explanation so if someone more knowledgeable wants to chime in go ahead, but that was my take away. It’s counterintuitive to me and the physics of ailerons and tails on the back end of a cone-shaped plane operating at subsonic speed aren’t applicable.

That seems logical, and so did a comment on SFN that said the larger surface area of an interstage helps provide more lift than a nosecone's, relieving the grid fins of part of their duty. So maybe say "stronger" turbulence & structural lift from an interstage to put the 2 ideas together if both are accurate.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: TripD on 12/22/2017 11:31 PM
Quote
The open cylinder of the interstage creates said turbulent airflow.

This doesn't seem correct.  Since the engine end is leading on the final return, all airflow will have passed through the fins before experiencing the open end of the interstage.  Or did I miss the context?

Edit/  I didn't include the part of the quote about the effect on the fins.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: zhangmdev on 12/22/2017 11:46 PM
Remember this?

https://www.nasa.gov/centers/dryden/multimedia/imagegallery/Shuttle/EC05-0166-27.html (https://www.nasa.gov/centers/dryden/multimedia/imagegallery/Shuttle/EC05-0166-27.html)

Having nose/tail cone to smooth the airflow and reduce drag is not necessarily good to landing.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/22/2017 11:46 PM
As I understand it, it's actually the fact that the smooth laminar airflow tends to *mostly* "stick" to the tapered nosecone --- but can detach suddenly, which causes a strong side force if/when it happens. What's worse, if the stage is allowed to "lean in" to the force generated, the airflow will reattach and then separate on the opposite side, leading to oscillation. (There are videos of this vortex-shedding oscillation floating around youtube, maybe even posted earlier in this thread.) It's "better" to have an open cylinder end, where the airflow detaches immediately in a predictable way.  Since the end can't be blunt on the booster when it's pointing up during ascent, instead the larger fins were added to ensure that they have sufficient control authority to counteract any vortex-shedding and prevent oscillation.

EDIT: the vortex-shedding oscillation is what caused the Tacoma narrows bridge to collapse, and I encountered an example in a walk near my house not too long ago (attached).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Herb Schaltegger on 12/22/2017 11:50 PM
Quote
The open cylinder of the interstage creates said turbulent airflow.

This doesn't seem correct.  Since the engine end is leading on the final return, all airflow will have passed through the fins before experiencing the open end of the interstage.  Or did I miss the context?

In a very simplified nutshell (and admittedly it's been a couple decades-plus since undergrad aerodynamics), the open end creates turbulent flow around the now-aft end of the falling/descending stage body. The grid fins have marginal overall effect on this.  But as a result of that turbulent flow, the grid fins have greater general control of the attitude (and thus flight path) of the stage than they would otherwise. With a nosecone on the now-aft end of the falling/descending stage body, the nosecone is acting in essence as a streamlined tailcone. That results in vastly different aerodynamics as opposed to a stage with an open-ended blunt cylinder interstage.  SpaceX's analysis has found that as a result, the grid fins on the boosters must be larger and have greater overall control authority to handle the changed aerodynamics.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: TripD on 12/23/2017 12:03 AM
That seems straight forward.  I was actually responding to cppetrie and wondering if the turbulence from the open interstage could actually provide turbulence to the fins for better control.  This was all pertaining to the issue of laminar vs. turbulent flow through the fins.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 12/23/2017 12:03 AM
In a very simplified nutshell (and admittedly it's been a couple decades-plus since undergrad aerodynamics), the open end creates turbulent flow around the now-aft end of the falling/descending stage body. The grid fins have marginal overall effect on this.  But as a result of that turbulent flow, the grid fins have greater general control of the attitude (and thus flight path) of the stage than they would otherwise. With a nosecone on the now-aft end of the falling/descending stage body, the nosecone is acting in essence as a streamlined tailcone. That results in vastly different aerodynamics as opposed to a stage with an open-ended blunt cylinder interstage.  SpaceX's analysis has found that as a result, the grid fins on the boosters must be larger and have greater overall control authority to handle the changed aerodynamics.

I wonder how close the trade on jettisoning the nose cones post booster separation vs enhancing the gridfin system was.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cppetrie on 12/23/2017 12:13 AM
In a very simplified nutshell (and admittedly it's been a couple decades-plus since undergrad aerodynamics), the open end creates turbulent flow around the now-aft end of the falling/descending stage body. The grid fins have marginal overall effect on this.  But as a result of that turbulent flow, the grid fins have greater general control of the attitude (and thus flight path) of the stage than they would otherwise. With a nosecone on the now-aft end of the falling/descending stage body, the nosecone is acting in essence as a streamlined tailcone. That results in vastly different aerodynamics as opposed to a stage with an open-ended blunt cylinder interstage.  SpaceX's analysis has found that as a result, the grid fins on the boosters must be larger and have greater overall control authority to handle the changed aerodynamics.

I wonder how close the trade on jettisoning the nose cones post booster separation vs enhancing the gridfin system was.
My recollection from the discussion in L2 at the time was that having no nose cone didn’t solve the problem because the location of the turbulent flow wasn’t right when no cone or interstage was present. There were some ideas on having the cone open to extend the cylinder in a fashion to replicate the aero effects of the interstage but it appears SpaceX just elected to use larger fins to solve the problem.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/23/2017 12:21 AM
In a very simplified nutshell (and admittedly it's been a couple decades-plus since undergrad aerodynamics), the open end creates turbulent flow around the now-aft end of the falling/descending stage body. The grid fins have marginal overall effect on this.  But as a result of that turbulent flow, the grid fins have greater general control of the attitude (and thus flight path) of the stage than they would otherwise. With a nosecone on the now-aft end of the falling/descending stage body, the nosecone is acting in essence as a streamlined tailcone. That results in vastly different aerodynamics as opposed to a stage with an open-ended blunt cylinder interstage.  SpaceX's analysis has found that as a result, the grid fins on the boosters must be larger and have greater overall control authority to handle the changed aerodynamics.

The laminar airflow reconnects around the nose (now tail cone). The region close to the booster passing though the grid fins minimally deviates and so functions to lose control authority. The larger grid fin's area includes the more turbulent outer radius flow and so regains the lost control authority.

None of this matters after the stage goes transonic.

I wonder how close the trade on jettisoning the nose cones post booster separation vs enhancing the gridfin system was.
Passive system improvements have much lower risk - it may be that larger fins for the core as well might become standard for other reasons.

Active separation systems are another separation event to fail, thus more costly. Worst parts are the increased weight/drag of the passive improvement. Perhaps also flight rate/erosion might matter if they intend high frequency FH flight rate?

Also, they've assembled the vehicle faster than expected. Interesting to see if they are as quick to make it fit on the TE, and have fit checks erect on the launch mount.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 12/23/2017 01:11 AM
An ejectable/jettisonable nose cone is another part that has to be replaced each time. More expensive grid fins were likely a clearly better trade.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: zhangmdev on 12/23/2017 01:25 AM
Will there be camera on the side booster? Consider where the nose cone begins, it is hard for a downward facing camera to observe those gird fins.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 12/23/2017 01:55 AM
An ejectable/jettisonable nose cone is another part that has to be replaced each time. More expensive grid fins were likely a clearly better trade.

Not to mention the fact you can’t even jettison the nosecone because the grid fins are inside it...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 12/23/2017 02:10 AM
An ejectable/jettisonable nose cone is another part that has to be replaced each time. More expensive grid fins were likely a clearly better trade.

Not to mention the fact you can’t even jettison the nosecone because the grid fins are inside it...

They could have made a 2-part assembly with a base/barrel section that housed the fins and control systems and a detachable upper/cone section, but clearly they chose a different route.  I'm sure lots of things played into that discussion beyond just reusability.  I was wondering on if it was an easy/clear choice or a more "could have gone either way" one.  Given they're already flying a reusable system, the improved grid fins seem like an easy choice. 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: tyrred on 12/23/2017 05:58 AM
Will there be camera on the side booster? Consider where the nose cone begins, it is hard for a downward facing camera to observe those gird fins.
Looking closely at the inboard nosecones, are those camera pods on each, facing downwards towards the yellow linkage apparatus?  Perhaps I'm wrong, but it seems like a good place to situate a camera (to a layman).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/23/2017 08:12 AM
Elon just tweeted this... 

https://twitter.com/elonmusk/status/944495421161742336
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: macpacheco on 12/23/2017 08:28 AM
The Titanium fins are installed on the side boosters to give them better glide ratio, reducing the duration of the boost back required that still gets the boosters to the LZ.
Since the center core lands on ASDS, they might handle the higher re-entry speed with a longer entry burn.
Just educated guesses, but it actually makes sense.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: zhangmdev on 12/23/2017 10:05 AM
Looking closely at the inboard nosecones, are those camera pods on each, facing downwards towards the yellow linkage apparatus?

The angle seems wrong. Grid fins and legs are likely outside field of view. But maybe they are more focused on observing how upper part of separation mechanism behaves. If they have side viewing cameras to document lower part of separation and keep recording all the way to touchdown, that would be awesome.

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: clongton on 12/23/2017 12:35 PM
Can someone explain why they didn't use the Tangent Ogive shape of the Ariane 5 booster?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/23/2017 12:42 PM
Can someone explain why they didn't use the Tangent Ogive shape of the Ariane 5 booster?
My only theory is for boundary layer/flow separation symmetry and controlabilty for landing (as it then becomes a "boatail" during entry and approach) and maintain known flight control algorithms from Falcon 9 S1... However; I have no actual aero data to compare both during descent to back it up... I don't believe they are going to jettison the nose cone AFAIK....
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/23/2017 12:50 PM
Can someone explain why they didn't use the Tangent Ogive shape of the Ariane 5 booster?

Maybe it's from the experiences with Titan and Shuttle that have conic booster nose cones. With the nose cones on the Ariane V aerodynamic  forces are always going to be pushing the booster into the stage. Maybe the force produced with conic booster nose cones depends on the speed of the booster and can vary more. So harder to deal with.

At least that is what I think.



Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/23/2017 01:02 PM
Can someone explain why they didn't use the Tangent Ogive shape of the Ariane 5 booster?

Maybe it's from the experiences with Titan and Shuttle that have conic booster nose cones. With the nose cones on the Ariane V aerodynamic  forces are always going to be pushing the booster into the stage. Maybe the force produced with conic booster nose cones depends on the speed of the booster and can vary more. So harder to deal with.

At least that is what I think.
With that in mind, it is interesting to note the current booster for SLS and the proposed "Dark Knight" configuration...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Herb Schaltegger on 12/23/2017 01:05 PM
Elon just tweeted this... 

https://twitter.com/elonmusk/status/944495421161742336

For those who don't do Twitter:

Quote
If you liked tonight’s launch, you will really like Falcon Heavy next month: 3 rocket cores & 3X thrust. 2 cores return to base doing synchronized aerobatics. 3rd lands on droneship.
3:10 AM - 23 Dec 2017

That's a lot more confident-sounding than prior statements.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 12/23/2017 01:23 PM
Can someone explain why they didn't use the Tangent Ogive shape of the Ariane 5 booster?
Because Ariane 5 doesn't care about recovering the side boosters? They will have off kilter aerodynamics due to the strong asymmetry.

Also because reducing loads on the core may not be as important to this vehicle as it is to Ariane 5?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/23/2017 01:25 PM
Because Ariane 5 doesn't care about recovering the side boosters?

Ariane 5 booster are recoverable, but it's not often done.
http://www.esa.int/esapub/bulletin/bullet85/gigo85.htm
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: clongton on 12/23/2017 01:30 PM
Can someone explain why they didn't use the Tangent Ogive shape of the Ariane 5 booster?

Maybe it's from the experiences with Titan and Shuttle that have conic booster nose cones. With the nose cones on the Ariane V aerodynamic  forces are always going to be pushing the booster into the stage. Maybe the force produced with conic booster nose cones depends on the speed of the booster and can vary more. So harder to deal with.

At least that is what I think.
With that in mind, it is interesting to note the current booster for SLS and the proposed "Dark Knight" configuration...

Yea I forgot about that. But you're right. The Dark Knight nose cone is essentially the same as the Ariane 5 booster nosecone.
As for pushing the booster toward the core, the Poles had an easy solution to that on their Meteor-2K rocket - simply rotate the cone around 180 degrees, which might even improve the whole concern.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: clongton on 12/23/2017 01:34 PM
Because Ariane 5 doesn't care about recovering the side boosters?


Ariane 5 boosters are recovered.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/23/2017 01:36 PM
Also because reducing loads on the core may not be as important to this vehicle as it is to Ariane 5?

I was wondering this too. In the shuttle the boosters lift from their tops so there is a strong cross beam there able to withstand high loads. Falcon booster lift from the bottom, I don't know about Ariane 5 but looking at cutaways I think the boosters lift from the bottom as there is no crossbeam at the top of the booster as with the shuttle ET. I have even less idea about the Titan IV.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 12/23/2017 02:19 PM
Because Ariane 5 doesn't care about recovering the side boosters?


Ariane 5 boosters are recovered.

But not reused?

Quote
The possibility of refurbishing and reusing the recovered boosters has, however, been rejected. It is currently considered a non-cost-effective option because of the specific design and reliability complications that this would incur. It is currently planned to recover four boosters per year.
(from http://www.esa.int/esapub/bulletin/bullet85/gigo85.htm cited above by nacnud.)

Why bother? Seriously. There might be some minor learnings but if you're not even going to TRY to reuse them, it's just a big boondoggle.  Some contracts must have been let and then found to be too expensive to cancel, or something.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/23/2017 02:31 PM
Why bother? Seriously. There might be some minor learnings but if you're not even going to TRY to reuse them, it's just a big boondoggle.  Some contracts must have been let and then found to be too expensive to cancel, or something.

You could have said the same about reusing the shuttle boosters, IIRC the refurbishment cost was quite close to the cost of just building new each time. The reason for getting them back on occation is engineering data, validating the design.

While it's obvious now the way to get to reuse is liquid boosters as the refurbishment cost is lower having the Ariane booster solid kept the knowledge of how to build large solid alive in Europe. And solids are great when it comes to sitting inert in silos for extended periods of time...  :-\
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lar on 12/23/2017 03:22 PM
You could have said the same about reusing the shuttle boosters (snip...)

It would be hard to prove now but I beleive I DID say exactly that, way back in the day.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/23/2017 03:42 PM
Can someone explain why they didn't use the Tangent Ogive shape of the Ariane 5 booster?

Because that would make the booster hard to fly and land on its own. (Imagine trying to land a plane with a tail rudder permanently angled to one side)

Also it that ULA is moving away from booster nose cones like that (the upgraded Atlas V SRBs have plain conical nose cones), so the benefits of them are clearly not significant.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: zhangmdev on 12/23/2017 04:22 PM
I remember someone said an SRB is virtually unsinkable after splashdown, if not retrieved those two giant steel casing floating around could be hazardous to shipping.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/23/2017 05:17 PM
Can someone explain why they didn't use the Tangent Ogive shape of the Ariane 5 booster?
Flight frequency? Need? Development schedule overload? Lifetime of vehicle?

Never really thought that FH has gotten the same amount of attention that F9/BFS/BFR have had.

It started out as "Falcon 9 Heavy" as a simple expedite, in part to launch those Iridium missions like last night. (I wonder if they just had bolted together three F9 1.0's and flown them as if a single expendable booster no separation of boosters, and accept the non optimality to begin.)

Instead, more like BO, they've obsessed with single core performance with enhanced engines, and the FH program has evolved constantly til the point that SLC-4E's TEL, which was intended to fly it, couldn't.

FH has become one of the last steps of the Falcon launch vehicle family, probably done before block 4/5 because you'd want to have the vehicle operational so you can apply the flight history to the reuse improvements for them to both share the FH/F9 economics closely (very much unlike DIVH which was much more problematic).

Possibly if FH has more applicability (like in the case of lunar free return flights?),  the tangent ogive's might be factored in.

As for Ariane, it only flew/flies with the side boosters, so all considerations for the entire vehicle were from the start.

My only theory is for boundary layer/flow separation symmetry and controllabilty for landing (as it then becomes a "boatail" during entry and approach) and maintain known flight control algorithms from Falcon 9 S1.
Nope. What it would do is change the area affected by the larger grid fins, shifting the center line off center.

The vehicles already have to compensate for asymmetries, and on the F9 RTLS they have been using greater angle of attack on the boosters, which provokes a similar asymmetry, which the guidance software deals with as well as things like crosswinds.

They will have off kilter aerodynamics due to the strong asymmetry.
Not really.

Just shifts CP going up, shifts "ineffectual" area coming down (you could lengthen the fins still more to compensate if you needed even more control authority above transonic, but I doubt it -- it's not going to tumble ;) ).

Quote
Also because reducing loads on the core may not be as important to this vehicle as it is to Ariane 5?
Reducing loads on the boosters means better mass fraction for all F9 boosters.

Side compressive loads on the booster core is the typical load holding the stack together, when you need it lower to max Q - the side TO cancels across the core's transverse loads bottom to top.

Also it that ULA is moving away from booster nose cones like that (the upgraded Atlas V SRBs have plain conical nose cones), so the benefits of them are clearly not significant.
The greater area/faster/longer duration of flight, the more it helps.

The benefit would be better mass fraction. If you fly enough, perhaps it matters. And its something you can do later if you want.

add:
Investigating the staging velocity and necessary choice implied, the height of the optimal tangent ogive would be above the core interstage, so perhaps there might be clearance issues with the core's gridfins that might complicate matters too.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 12/23/2017 05:44 PM
Because Ariane 5 doesn't care about recovering the side boosters?


Ariane 5 boosters are recovered.

Not quite correct Chuck. The booster for Ariane 5 have been recovered only a few times. It was for post-flight inspection to validate the design.

Standard MO for Ariane 5 boosters is to fall into the drink and sink.


But not reused?
Quote
The possibility of refurbishing and reusing the recovered boosters has, however, been rejected. It is currently considered a non-cost-effective option because of the specific design and reliability complications that this would incur. It is currently planned to recover four boosters per year.
(from http://www.esa.int/esapub/bulletin/bullet85/gigo85.htm cited above by nacnud.)

Why bother? Seriously. There might be some minor learnings but if you're not even going to TRY to reuse them, it's just a big boondoggle.  Some contracts must have been let and then found to be too expensive to cancel, or something.

Recovery of the boosters proved to be extremely troublesome. The ELS package was experimental and unreliable. The very first recovery attempt failed completely because of that.

Even the planned four retrievals per year went away quickly after the first successful recovery validated the basic design of the boosters.

The fact that no humans were going to fly on Ariane 5 (after Hermes was cancelled) also aided the decision to not recover the boosters after the initial sets.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FutureSpaceTourist on 12/26/2017 03:31 PM
Usual amazing work by Oli Braun:

Quote
Some FH artwork :) available as high res prints anytime soon :) @NASASpaceflight @FHeavyBooster @SpaceXPad39A

https://twitter.com/oli_braun/status/945647229456527360 (https://twitter.com/oli_braun/status/945647229456527360)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/26/2017 03:56 PM
Usual amazing work by Oli Braun:

Quote
Some FH artwork :) available as high res prints anytime soon :) @NASASpaceflight @FHeavyBooster @SpaceXPad39A

https://twitter.com/oli_braun/status/945647229456527360 (https://twitter.com/oli_braun/status/945647229456527360)

That guy is amazing
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/26/2017 04:13 PM
Wow - FH payload picture on the update thread. That’s a First I believe! You can see the TEL inside. Does this mean a static fire with payload attached??
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dnavas on 12/26/2017 04:18 PM
https://twitter.com/elonmusk/status/943420026593337344

@elonmusk
Falcon Heavy at the Cape

As a tinker-toy construct, it seemed so obvious, but faced with the reality, I wonder how I ever thought this was going to work.  Imagining the staging is giving me the heebie jeebies.  Perhaps particularly after having reviewed Falcon 1 launches....
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/26/2017 04:24 PM
Wow - FH payload picture on the update thread. That’s a First I believe! You can see the TEL inside. Does this mean a static fire with payload attached??

Possibly!

Either that or they're moving it there to free up space in the integration facility.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dnavas on 12/26/2017 04:29 PM
Does this mean a static fire with payload attached??

Maybe just pictures before WDR?  Particularly if you can nab Zuma and FH on pads at the same time?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: WH2OPaddler on 12/26/2017 05:16 PM
Now that the 1st FH is assembled, any word on when the static fire is planned?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: tvg98 on 12/26/2017 05:18 PM
Now that the 1st FH is assembled, any word on when the static fire is planned?

NET early January.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 12/26/2017 05:32 PM
Now that the 1st FH is assembled, any word on when the static fire is planned?
First rollout may occur before the end of the year for a dry systems test with the fully integrated stack.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: pospa on 12/26/2017 07:06 PM
Great find. Higher res attached.

I would say we can also see for the first time FH integrated to TEL in the background darkness of HIF. :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: douglas100 on 12/26/2017 07:43 PM
Looks like there's another single core as well, parked to the right of the FH/TEL.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: douglas100 on 12/26/2017 07:47 PM
Does this mean a static fire with payload attached??

Maybe just pictures before WDR?  Particularly if you can nab Zuma and FH on pads at the same time?

No reason why they can't do the static fire fully assembled. It's not like it's a customer's payload or anything. If they lose the vehicle on the pad then the loss of the Tesla is the least of their worries.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cro-magnon gramps on 12/26/2017 08:06 PM
I created a rough time line on Friday. The TEL integration was pre CHRISTMAS day with TEL fit check happening after boxing day. That led into a roll out around the weekend before NewYears Day. The static fire won't happen before ZUMA launches because they will be into pad Fit checks and the danger posed by an explosion on the pad at 39A. That leads to a Net  of Jan 11th to 15th for launch. AT LEAST that's my rationalization: :D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: pospa on 12/26/2017 08:08 PM
Looks like there's another single core as well, parked to the right of the FH/TEL.

That light ring is assembly jig only. No other boosters then FH in HIF right now.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RocketLover0119 on 12/26/2017 08:17 PM
Also tried my attempt at removing the darkness from the photo

Great find. Higher res attached.

I would say we can also see for the first time FH integrated to TEL in the background darkness of HIF. :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Flying Beaver on 12/26/2017 08:37 PM
Yeah.. Not getting any better than this :P.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: clongton on 12/26/2017 09:16 PM
Now that the 1st FH is assembled, any word on when the static fire is planned?
First rollout may occur before the end of the year for a dry systems test with the fully integrated stack.

Elon said in a tweet (I'll have to look for it now) that **IF** the WDR goes all the way without a hitch that they would proceed immediately to the static fire.
That's a big if for a new vehicle.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 12/26/2017 09:22 PM
Now that the 1st FH is assembled, any word on when the static fire is planned?
First rollout may occur before the end of the year for a dry systems test with the fully integrated stack.

Elon said in a tweet (I'll have to look for it now) that **IF** the WDR goes all the way without a hitch that they would proceed immediately to the static fire.
That's a big if for a new vehicle.
yep Tweets are a bit behind L2.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Norm38 on 12/27/2017 05:28 PM
It is a new vehicle and it isn't. They have to fuel the three cores separately, procedures for that should be the same as for F9. Did they build two extra tank farms, meaning the three cores are completely separate?  Or one big farm?  Triple flow that splits three ways adds complexity over separate feeds. But once the vehicle is fueled they should be able to quickly static fire. What would prevent that?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 12/27/2017 08:53 PM
Yeah.. Not getting any better than this :P.

Is that the top of the second stage, or is it the interstage? It looks white and convex like the cap normally atop the upper stage during static fires, not shadowed and hollow like the interstage.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RocketLover0119 on 12/27/2017 09:06 PM
If you look reeeeaaaalllyy hard I think I can make out the cap on top..... Maybe, maybe not, may just be seeing things

Yeah.. Not getting any better than this :P.

Is that the top of the second stage, or is it the interstage? It looks white and convex like the cap normally atop the upper stage during static fires, not shadowed and hollow like the interstage.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 12/27/2017 09:16 PM
If you look reeeeaaaalllyy hard I think I can make out the cap on top..... Maybe, maybe not, may just be seeing things

Yeah.. Not getting any better than this :P.

Is that the top of the second stage, or is it the interstage? It looks white and convex like the cap normally atop the upper stage during static fires, not shadowed and hollow like the interstage.
AFAIK, FH was fully integrated minus payload unit for WDR/SF ahead of transfer and mate to the TEL.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ketivab on 12/28/2017 10:38 AM
Chris Bergin in update thread: (https://forum.nasaspaceflight.com/index.php?topic=44376.msg1764936#msg1764936)
Quote
We understand the big rocket is going to be on the pad very soon, or at least rolled out (fit checks can take a fair amount of work). Will be the full stack, per the fit check requirements. ...
Does 'full stack' mean 'with payload fairing'?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/28/2017 10:39 AM
I think so. It's not a full fit check without it.  :D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 12/28/2017 11:07 AM
Yep, full stack is launch configuration.....including the car. ;D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ketivab on 12/28/2017 11:46 AM
Thank you!

I can't wait!  ;D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RocketLover0119 on 12/28/2017 12:01 PM
So just to clarify, this is simply a rollout/erect test, not a WDR?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jakusb on 12/28/2017 12:19 PM
So just to clarify, this is simply a rollout/erect test, not a WDR?

Could be anything...
- Photo-op
- Fit test with GSE
- WDR unlikely on first roll-out

I am going for combo of first 2... ;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RocketLover0119 on 12/28/2017 12:24 PM
My other question s how "soon?" Today? Few hours?

Yep, full stack is launch configuration.....including the car. ;D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cro-magnon gramps on 12/28/2017 12:42 PM
I created a rough time line on Friday. The TEL integration was pre CHRISTMAS day with TEL fit check happening after boxing day. That led into a roll out around the weekend before NewYears Day. The static fire won't happen before ZUMA launches because they will be into pad Fit checks and the danger posed by an explosion on the pad at 39A. That leads to a Net  of Jan 11th to 15th for launch. AT LEAST that's my rationalization: :D

I'm looking for WDR / SF at about the 7th - 8th of January, 3 days after Zuma Launches... with LRR finalized 2-3 days later, and launch NET January 11th ranging to January 15th... keeping eyes, fingers, and toes crossed... :D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RocketLover0119 on 12/28/2017 01:39 PM
Julia Bergeron on twitter said that roadblocks are in place and the bus tours to 39a are not taking their normal behind the hanger route, indicating rollout is indeed today

EDIT: tweet to it:  Conversation
Julia
Julia
@julia_bergeron
·
33m

Embedded
2
1
11
Chris B - NSF
Chris B - NSF
@NASASpaceflight
·
24m
Good work! First sighting is likely to be on base, with the HIF door open and the FH at the base of the ramp on the TEL.  Getting up the ramp and vertical is a lot of work, so the trick will be to get confirmation when FH is out of the barn :)
2
7
Julia
Julia
@julia_bergeron
Replying to @NASASpaceflight and 2 others
Hard shot to get since roadblocks are up and no bus tour there. First shot may come from somebody that works at KSC...if they dare...

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RocketLover0119 on 12/28/2017 01:47 PM
GOING VERTICLE!!!!!!! According to SFN- Falcon Heavy is going vertical for the first time at pad 39A at the Kennedy Space Center.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: loki on 12/28/2017 01:59 PM
Stand up Heavy!! :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RocketLover0119 on 12/28/2017 02:04 PM
SFN reports a fully vertical FH!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 12/28/2017 02:12 PM
Fast.  Barn to vertical.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Herb Schaltegger on 12/28/2017 02:26 PM
This is where the geometric dimensioning and tolerancing training for your engineers and drafting staff come into play. Difficult enough for a single linear structure like a TEL. All those hold-downs and service masts for three cores has got to be ... tricky. :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 12/28/2017 02:34 PM
This is where the geometric dimensioning and tolerancing training for your engineers and drafting staff come into play. Difficult enough for a single linear structure like a TEL. All those hold-downs and service masts for three cores has got to be ... tricky. :)

We'll see how long they stay on the hill for fit checks... should tell us something.
Didn't waste much time between TEL heading into the HIF* (+ Christmas) to roll-out and vertical.

* Assume all the hold-downs and tail service masts are mated to the boosters in the HIF, and TSMs were previously mated to their plumbing on the pad last week or two.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cebri on 12/28/2017 02:41 PM
Quote
(https://cdn.discordapp.com/attachments/316186751565824001/395963737695322123/DSJOJPmXUAE6GYr.png)

credit to https://twitter.com/julia_bergeron

There she is.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: PahTo on 12/28/2017 02:54 PM
Might just be the angle or an artifact of the photo (or the earlier renders), but the interstage/2nd stage looks longer/taller than renders over the past years...
(that is, the PLF appears higher/farther from the side boosters)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Basto on 12/28/2017 02:57 PM
Might just be the angle or an artifact of the photo (or the earlier renders), but the interstage/2nd stage looks longer/taller than renders over the past years...
(that is, the PLF appears higher/farther from the side boosters)

It looks consistent with the renders on SpaceX’s website.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cebri on 12/28/2017 03:03 PM
A "clearer" shot.

Quote
(https://i.imgur.com/DWVikwB.jpg)

Credit to @ExploreSpaceKSC
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/28/2017 03:08 PM
Two questions:

1) Is that a BLACK landing leg on the left-hand booster or just a play of the light?

2) Are people saying that the FH interstage / 2nd stage is longer than the F9? If so, that's news to me - I thought that the FH and the F9 were the same height...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/28/2017 03:12 PM
I think the 'landing leg' you are seeing is a rain bird.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ben the Space Brit on 12/28/2017 03:14 PM
Quote
It is real! Look at that @SpaceX  #FalconHeavy 🚀 View from Playalinda National Seashore vista. @NASASpaceflight @lorengrush

https://twitter.com/julia_bergeron/status/946404807379771394

It's good to see FH-001 on the pad. Maybe, in the not-too-distant future, we'll be seeing crewed BLEO flights from LC-39A again!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: billh on 12/28/2017 03:16 PM
Here's a video of FH going vertical supplied by a friend on Facebook.
https://www.facebook.com/ADPedro88/videos/10155370936843165/
Video is from SpaceflightNow:
https://spaceflightnow.com/2017/12/28/time-lapse-video-falcon-heavy-goes-vertical/
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/28/2017 03:17 PM
FH "fills up the pad" quite nicely... 8)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ben the Space Brit on 12/28/2017 03:32 PM
Maybe more knowledgable folks  than me can say: As there is no launch license in place for the FH Demo Launch that I am aware of, what is the earliest possible date from today that they can launch this vehicle?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Herb Schaltegger on 12/28/2017 03:36 PM
Maybe more knowledgable folks  than me can say: As there is no launch license in place for the FH Demo Launch that I am aware of, what is the earliest possible date from today that they can launch this vehicle?
The FAA has sometimes issued prior launch licenses the day before a launch, even on a weekend.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 12/28/2017 03:44 PM
Maybe more knowledgable folks  than me can say: As there is no launch license in place for the FH Demo Launch that I am aware of, what is the earliest possible date from today that they can launch this vehicle?
The FAA has sometimes issued prior launch licenses the day before a launch, even on a weekend.

...and the license might not be publicly posted on the FAA web site until after the launch has already happened (maybe not even then).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dpark on 12/28/2017 06:04 PM
I think the 'landing leg' you are seeing is a rain bird.
So no landing legs yet, huh? Was that expected for the WDR?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/28/2017 06:06 PM
I think the 'landing leg' you are seeing is a rain bird.
So no landing legs yet, huh? Was that expected for the WDR?

They are there. Just white. Look closer in the image from this post: http://forum.nasaspaceflight.com/index.php?topic=42705.msg1765037#msg1765037
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ketivab on 12/28/2017 06:09 PM
I think the 'landing leg' you are seeing is a rain bird.
So no landing legs yet, huh? Was that expected for the WDR?
It has white landing legs. See THESE (https://twitter.com/elonmusk/status/943420026593337344) photos from Elon.  ;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/28/2017 06:14 PM
Neat comparison images, source: http://www.forum-conquete-spatiale.fr/t17713p250-spacex-lancement-falcon-heavy-janvier-2018#408836

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: saliva_sweet on 12/28/2017 06:16 PM
So, as she stands right there... is it the most powerful rocket since the Saturn V? Or at least the Shuttle?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Craftyatom on 12/28/2017 06:23 PM
So, as she stands right there... is it the most powerful rocket since the Saturn V? Or at least the Shuttle?
Less liftoff mass and thrust than shuttle, but more payload than anything since Energia.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/28/2017 06:23 PM
The largest potentially payload to LEO/above since Saturn V.

(And the cheapest to (re)launch hands down.)

Finally, the TE no longer looks small and empty, as it did with just a Falcon 9 on it.

So ... how long has this been waiting on by those here? Good Christmas for you all?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: PahTo on 12/28/2017 06:25 PM
So, as she stands right there... is it the most powerful rocket since the Saturn V? Or at least the Shuttle?

She hasn't flown yet, but...
most powerful liquid rocket since Saturn V (7+mlf).  Shuttle had more total thrust (approx 5mlf for FH v 6+mlf)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: DecoLV on 12/28/2017 06:31 PM
I never thought we would see this day. FH is real.  :D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Semmel on 12/28/2017 06:31 PM
So, as she stands right there... is it the most powerful rocket since the Saturn V? Or at least the Shuttle?

Energia was the most powerful rocket since Saturn V and still is. Unfortunately, it flew only two times, in 1987 and 88 and had a LEO capacity of about 100 mT and . More than Falcon Heavy. Space Shuttle could only get 28mT to LEO. In pure payload numbers, Shuttle is more comparable to F9 B5 expendable (not quite but close) than FH. But of course Shuttle could launch payload and astronauts at the same time and return the orbital stage to earth, which is quite some different game than Falcon Heavy.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/28/2017 06:34 PM
I never thought we would see this day. FH is real.  :D
Perhaps we need to see a launch/success ... for it to be ... real?

But for sure ... not a paper rocket.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ike17055 on 12/28/2017 06:39 PM
Crud.  I just left the cape this morning after ending a 10-day vacation trip there. What time was the pad appearance? Sitting in Sanford airport waiting for my flight and read about this just a few minutes ago.  sooooo close....
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: PahTo on 12/28/2017 06:40 PM
I never thought we would see this day. FH is real.  :D
Perhaps we need to see a launch/success ... for it to be ... real?

But for sure ... not a paper rocket.

Yeah--that's where I was going with my answer--need to have an operational rocket (why I left out Energia, though at least she/they flew a couple times as a test).  And of course thrust v performance, etc etc.
btw, nice hat, SG1962...
:)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/28/2017 06:48 PM
This is coming together at the pad a lot faster than I remember the inaugural Delta IV Heavy.

If it hot fires/launches well, has adequate performance, and lands all ... it may well be a very capable LV, and the first cluster vehicle to achieve what all the others could not - feasibility.

Yes DIVH works but it's a nightmare in many ways to get on/off the pad. Angara has been many decades in the making. Both don't have a huge number of flights.

If it does go well, and does so within two years again ... many heads will be turned. Congrats SX, you did it much faster than I thought you would.

Here's betting on a smooth inaugural flight.

I never thought we would see this day. FH is real.  :D
Perhaps we need to see a launch/success ... for it to be ... real?

But for sure ... not a paper rocket.

Yeah--that's where I was going with my answer--need to have an operational rocket (why I left out Energia, though at least she/they flew a couple times as a test).  And of course thrust v performance, etc etc.
Indeed.

(Energia also was a costly, touchy ... iffy thing.) F9/FH seem to be more about "utility" thenthan "shock and awe".

Quote
btw, nice hat, SG1962...
:)
Thanks, it's festive for this FH season ;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Oersted on 12/28/2017 06:59 PM
Space Shuttle could only get 28mT to LEO.

If we think of the whole orbiter (gross lift-off weight 110 tonnes) as the "payload" then STS got a lot more into LEO. But that is of course a question of how you define payload. However, I think we can consider the orbiter as a spaceship the same way that we consider Dragon a spaceship, and then indeed STS got 110 tonnes into LEO. The fact that the orbiter was reusable supports considering it as "payload". 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Semmel on 12/28/2017 07:01 PM
This is coming together at the pad a lot faster than I remember the inaugural Delta IV Heavy.

If it hot fires/launches well, has adequate performance, and lands all ... it may well be a very capable LV, and the first cluster vehicle to achieve what all the others could not - feasibility.

I agree with you on the examples you gave.

But dont forget Soyuz. With more than 1000 flights over many iterations, its in an entirely different league than any other launcher in the world. And its a cluster vehicle. I would say it counts in terms of feasibility ;-)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Oersted on 12/28/2017 07:05 PM
Can't comment on why I say this, but man I am happy that I have an L2 membership of this site :-)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 12/28/2017 07:05 PM
F9/FH seem to be more about "utility" then "shock and awe".

(then vs. than)  I don't think that was the one you meant to use there.  But it fits, too, so I'll allow it.   :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/28/2017 07:08 PM
Space Shuttle could only get 28mT to LEO.

If we think of the whole orbiter (gross lift-off weight 110 tonnes) as the "payload" then STS got a lot more into LEO. But that is of course a question of how you define payload. However, I think we can consider the orbiter as a spaceship the same way that we consider Dragon a spaceship, and then indeed STS got 110 tonnes into LEO. The fact that the orbiter was reusable supports considering it as "payload".
STS was also able to transport crew along with payload - so not exactly apples to apples when comparing to FH. Perhaps FH with a Dragon 2 - then STS wins on crew # and payload capacity and FH wins on throw distance...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: speedevil on 12/28/2017 07:17 PM
New fairing design visible in photographs just after rollout.
(https://i.imgur.com/4FhDRY3m.jpg)
( https://twitter.com/Helodriver2004/status/851553717077889029 )
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/28/2017 07:20 PM
Space Shuttle could only get 28mT to LEO.

If we think of the whole orbiter (gross lift-off weight 110 tonnes) as the "payload" then STS got a lot more into LEO. But that is of course a question of how you define payload. However, I think we can consider the orbiter as a spaceship the same way that we consider Dragon a spaceship, and then indeed STS got 110 tonnes into LEO. The fact that the orbiter was reusable supports considering it as "payload".

Relax, shuttle huggers, there are still records it holds that aren't broken. :) Come back in a few years, though...  ;D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: loki on 12/28/2017 07:32 PM
Space Shuttle could only get 28mT to LEO.

If we think of the whole orbiter (gross lift-off weight 110 tonnes) as the "payload" then STS got a lot more into LEO. But that is of course a question of how you define payload. However, I think we can consider the orbiter as a spaceship the same way that we consider Dragon a spaceship, and then indeed STS got 110 tonnes into LEO. The fact that the orbiter was reusable supports considering it as "payload".

Please, define "Spaceship".
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: NX-0 on 12/28/2017 07:50 PM
Neat comparison images, source: http://www.forum-conquete-spatiale.fr/t17713p250-spacex-lancement-falcon-heavy-janvier-2018#408836

Astronauts are going to need a bike to get from one end of the CAA to the Dragon 2.
That's going to be quite a walk...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cuddihy on 12/28/2017 09:23 PM
So  is it possible they would proceed directly to static fire TODAY???!!!???
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Herb Schaltegger on 12/28/2017 09:23 PM
So  is it possible they would proceed directly to static fire TODAY???!!!???

No. There is L2 info if you're a member, but short answer is no.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Craig_VG on 12/28/2017 09:24 PM
So  is it possible they would proceed directly to static fire TODAY???!!!???

No, consensus seems to be that they will be waiting until after Zuma (Jan 4)

EDIT: living in the past...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 12/28/2017 09:27 PM
Whoa. That escalated quickly! ;D

It's a positive time, so rather than trawling back through a sudden flood of report to mods...

Keep Calm and Falcon Heavy.

--

People ignored this, so now I'm trimming the thread. You only have yourselves to blame! :)

Thread title helps you. "SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion" <---we have threads for general FH stuff and most of it was about comparing with Shuttle, which is both wrong and totally not on topic.

Sent most of the longer off topic posts back to the members who created them. Personally I'd let you all go nuts, but people complain, lots of people.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 12/28/2017 09:36 PM
So  is it possible they would proceed directly to static fire TODAY???!!!???
No. Not this week Only dry tests and a dry dress rehearsal per say for now. The public side should here soon as to when the Static fire and targeted launch date is.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Endeavour_01 on 12/28/2017 11:39 PM
What a beautiful site to see. FH on the pad.  :D I have to admit those comparison images that Lars-J posted make me feel a bit emotional. I guarantee you that if this thing launches during my Physics II class I am stopping lecture and putting it up on the screen. I have a good feeling that we will be witnessing an important part of space history.  :D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: david1971 on 12/29/2017 02:26 AM
I guarantee you that if this thing launches during my Physics II class I am stopping lecture and putting it up on the screen. I have a good feeling that we will be witnessing an important part of space history.  :D

You won't be the only physics professor doing that.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Brovane on 12/29/2017 03:00 AM
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?

 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mme on 12/29/2017 05:31 AM
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?
I bet they leave it attached. It's not a "real" payload. But I have no inside information.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: docmordrid on 12/29/2017 06:20 AM
ISTM it gets either a ride to space or a Viking funeral. Either is preferable to an auto parts yard.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: zhangmdev on 12/29/2017 07:36 AM
Will this static fire test be different? Longer duration? 20 sec? Or multiple times?
 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: topopesto on 12/29/2017 07:57 AM
I'm very happy for this new news! I like to see the FH on the PAD 39A. The 2018 to start good!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ben the Space Brit on 12/29/2017 08:45 AM
It amazes me how difficult it is to scale some of these pictures in my head. I didn't really understand how wide the FH payload fairing is until I saw that a Tesla Roadster can be fit in one horizontally rather than be flipped up so it points along the long axis of the fairing!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ricmsmith on 12/29/2017 08:59 AM
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?

 

I'm almost certain they'll leave it attached, it's not a customer payload - just a mass simulator, it's not a point of failure during the static fire. In fact, fuelling and COPV issues aside, I don't think the static fire itself is going to be at all problematic, certainly not from a catastrophic failure point of view. Things are only really going to get interesting post launch. Can they control 27 engines across 3 cores and keep them balanced? Will there be unanticipated mechanical or (perhaps more likely) aerodynamic loads? Any of those could lead to mission failure.

I don't have any inside line on this, just my personal view.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: matt_ellis on 12/29/2017 09:17 AM
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?

 

I'm almost certain they'll leave it attached, it's not a customer payload - just a mass simulator, it's not a point of failure during the static fire. In fact, fuelling and COPV issues aside, I don't think the static fire itself is going to be at all problematic, certainly not from a catastrophic failure point of view. Things are only really going to get interesting post launch. Can they control 27 engines across 3 cores and keep them balanced? Will there be unanticipated mechanical or (perhaps more likely) aerodynamic loads? Any of those could lead to mission failure.

I don't have any inside line on this, just my personal view.

I think the static fire test has the potential to be interesting for exactly the same reasons as you list for launch - getting all 27 engines to fire up in a balanced manor without RUD... (e.g. torque stresses ripping the rocket apart, not to mention 3 times the potential failure points of a standard F9) 

No doubt the SpaceX engineers have run numerous simulations and looked at data from the nearly 50(!) previous F9 launches, but I am sure there will be a 'Pucker Factor' on this test as well as the launch.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: JamesH65 on 12/29/2017 09:21 AM
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?

 

I'm almost certain they'll leave it attached, it's not a customer payload - just a mass simulator, it's not a point of failure during the static fire. In fact, fuelling and COPV issues aside, I don't think the static fire itself is going to be at all problematic, certainly not from a catastrophic failure point of view. Things are only really going to get interesting post launch. Can they control 27 engines across 3 cores and keep them balanced? Will there be unanticipated mechanical or (perhaps more likely) aerodynamic loads? Any of those could lead to mission failure.

I don't have any inside line on this, just my personal view.

My view on the multi engine control thing is it's not a problem. They already control 9 engines very successfully. There are of course some added complications (The three cores need to be synchronised to know what each is doing in order to compensate for things going on) , but they have had a long time to work through the control software and should have it pretty much good enough by now! As for aero loads, again, they have had years to work this out in CFD sims, which of course are not perfect, but pretty damn good.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ben the Space Brit on 12/29/2017 10:12 AM
Is this just a fit test with payload/fairing attached to verify the TEL and will it be removed before the static fire?

The only reason to remove the payload before the static fire is to protect the customer's payload from any possible catastrophic failure during the test. That isn't a consideration for this flight.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: StuffOfInterest on 12/29/2017 10:15 AM
Seeing all of the photos of the FH vertical left me with two questions, one that can be answered if someone has better eyes than me and one that probably can't be answered yet.

First, can anyone tell if the TE is providing support to the top of the side boosters or are they only supported by the attachment to the center core?  The pictures of the back side of the rocket are not very clear and although it looks like there may be something back there I can't tell for sure.

Second, I know the top support will fold forward to get out of the way of the grid fins.  Any speculation on if that support will fold while the center core is under thrust or if they will wait until staging to fold it?  When the side boosters go I presume the rocket will be above enough of the atmosphere that there won't be any significant aerodynamic load on the support so it may just make sense to let it stay out there until first stage thrust shuts off.  Less power in the retraction piston required.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/29/2017 10:53 AM
My guess is they’ll remove the payload prior to static fire. Why? Because that’s now SOP for their customers’ payloads. So they will want to try to replicate that process as accurately as possible. Additionally, demating and mating a payload to a FH stack would be good practice as I’m sure there are subtle differences to the same operation for F9.

Regardless, we’ll know soon enough. Which is amazing!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 12/29/2017 11:16 AM
Yeah, I'm really not sure. Standard is to remove the payload, but yes it's not some expensive satellite....and they may want some three core ignition data on how the entire stack behaves.

I've seen notes claiming both scenarios, so I don't know for sure.

More people heading down to KSC today, so let's keep an eye on the rocket, in case they lower her off the pad, so we can at least warn people on a several hour car trip.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 12/29/2017 12:07 PM
Yeah, I'm really not sure. Standard is to remove the payload, but yes it's not some expensive satellite....and they may want some three core ignition data on how the entire stack behaves.

I've seen notes claiming both scenarios, so I don't know for sure.

More people heading down to KSC today, so let's keep an eye on the rocket, in case they lower her off the pad, so we can at least warn people on a several hour car trip.

I really wish SpaceX (or somebody else who had cameras in the vicinity) would livestream the first Falcon Heavy SF, like what happened for the first Falcon 9.  Even with zero commentary, discussion, talking, etc.  That would definitely be lit.  [sorry, couldn't help myself there]

http://forum.nasaspaceflight.com/index.php?topic=20787.0
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 12/29/2017 12:13 PM
My guess is they’ll remove the payload prior to static fire. Why? Because that’s now SOP for their customers’ payloads. So they will want to try to replicate that process as accurately as possible. Additionally, demating and mating a payload to a FH stack would be good practice as I’m sure there are subtle differences to the same operation for F9.

Regardless, we’ll know soon enough. Which is amazing!

SOP is to fire first, then mate the payload. They don't demate during a nominal flow.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Chris Bergin on 12/29/2017 12:33 PM
Yeah, I'm really not sure. Standard is to remove the payload, but yes it's not some expensive satellite....and they may want some three core ignition data on how the entire stack behaves.

I've seen notes claiming both scenarios, so I don't know for sure.

More people heading down to KSC today, so let's keep an eye on the rocket, in case they lower her off the pad, so we can at least warn people on a several hour car trip.

I really wish SpaceX (or somebody else who had cameras in the vicinity) would livestream the first Falcon Heavy SF, like what happened for the first Falcon 9.  Even with zero commentary, discussion, talking, etc.  That would definitely be lit.  [sorry, couldn't help myself there]


http://forum.nasaspaceflight.com/index.php?topic=20787.0


Good call. I'll ask them as they absolutely have all the cameras for it.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FutureSpaceTourist on 12/29/2017 01:24 PM
Quote
A quick check of the coast reveals no #FalconHeavy on pad. Although up in the late night hours, it appears to possibly be back in the barn. Is it all good or adjustments needed? Nobody knows yet. @SpaceX

https://twitter.com/julia_bergeron/status/946737095565107204

So FH spent less than a day at the pad doing fit checks.

Is that what people expected? Good news, or not?! I don’t know what the procedures would be for something like this. Assuming there were some snags to fix, would they try and do that with FH at the pad or would it go back to the HIF first?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ben the Space Brit on 12/29/2017 01:27 PM
I imagine that there will be more appearances of the vehicle at the pad. After all, they have to complete the launch campaign for Zuma before SpaceX's East Range team doing any serious work with the FH demonstration flight. I imagine, for now, they're going through connection tests and taking the opportunity of having an FH assembled to make sure the umbilicals and command and control data lines all work properly for a three-core stack.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dnavas on 12/29/2017 01:53 PM
I think the static fire test has the potential to be interesting for exactly the same reasons as you list for launch - getting all 27 engines to fire up in a balanced manor without RUD... (e.g. torque stresses ripping the rocket apart, not to mention 3 times the potential failure points of a standard F9)

I think it also wise to remember that all companies have an operating philosophy, and that when operation falls outside of well-practiced norms, bad things can happen.  SpaceX is more of a design, test, and fix company than is standard in the industry (at least, from what I've seen), and that suits them because it allows them to try things other companies won't.  Other companies have designed rockets with higher "throw weight to orbit" [dodging 'payload'] where two human beings were going to be part of that "throw weight" on first launch -- that requires a different operating philosophy.  I don't want to be distracted by better or worse, it's just different.  The real problem for SpaceX is that there hasn't been a test of all 27 going off outside of sims, and sims don't tend to model random corrosion problems in nuts (for example).  What is it that they've missed?  Untested is always dangerous.

I'm short, and a little past middle-aged, but I'm not that short or that old (or that wise), and I don't run around forests fronting my direct objects, so I'll try not to act as if I am, but ...  But, if I had to lay down odds for full mission success, they would not be extraordinarily high.  Their first stage landings, which are amazing, were "hard fought".  And two of the first three Falcon 1 launches had problems with stage recontact.  The entire launch regime has "new" written all over it.  Because, hey, while we're at it, why not just go interplanetary....  I'm sure that SpaceX believes there is a reasonable chance of success here, but there's also a reason why they're not launching a "pay"load.

I really, really want to see a success here.  I'm going to be completely distracted from work until launch.  As an engineer, I'll worry about what's being forgotten or overlooked even if I will be concocting plans for building a moon colony and launching a Stanford Torus in my head.  I really hope a successful launch proves every fear I have wrong.  But it seems to me that an ounce of humility goes a long way until then.  The thing I know is, whether the first rocket fails or succeeds, there will be one that works.  Whatever bad thing happens, that thing will get fixed.  Because that's what SpaceX does.

["The cave.  Remember your failure at the cave!"  Urk .. Damn.]
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/29/2017 02:06 PM
Personally I give this mission high probably of success. This is not the SpaceX of Falcon 1, nor is it the SpaceX of the first landing attempts, or of the rammed 2nd stage, or of the LOX curfuffle last year.

This is the SpaceX of now - a SpaceX that has solved booster return, stage separation, densified props, fairing separation, TEL protection, precision RADAR distance measurement, engine relights, ... (I can go on, but you get the idea).

SpaceX has fought hard to learn hard lessons - and these lessons are directly applicable to the FH.

And as a side note - it’s also the same reason I marvel when people place New Glenn in the mix as if it’s a done deal. BO has a huge and daunting task ahead of itself before the have a dependable orbital class launcher. I’m sure they’ll succeed, but SpaceX has already put many of these lessons behind them and will keep pushing forward while BO has still to learn those same lessons...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: wannamoonbase on 12/29/2017 02:09 PM
I think the probability of success is pretty high, but not as high as a F9 of course.

SpaceX has experience, latest design and modeling technology.  Things can happen but I don’t think there are many unknowns and that SpaceX will be conservative on this first one, as much as they can be anyway.   
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mn on 12/29/2017 02:28 PM
Quote
torque stresses

So I've seen this mentioned several times but I never saw an explanation.

Can someone please explain what this is about, and in particular why it would be more difficult on 3 cores vs 1 core.

(My simple mind would think that whatever stress is induced by the engines is local to the core, so you don't have 3 times the stress, you just have the same stress 3 times)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 12/29/2017 02:40 PM
Quote
torque stresses

So I've seen this mentioned several times but I never saw an explanation.

Can someone please explain what this is about, and in particular why it would be more difficult on 3 cores vs 1 core.

(My simple mind would think that whatever stress is induced by the engines is local to the core, so you don't have 3 times the stress, you just have the same stress 3 times)
Generally speaking single propeller boats can only back down in one direction - this is because the propeller is rotating in one direction, thereby imparting a rotational torque on the boat (visualize a prop "walking" along the ground as it turns - that will show you the direction of the torque.) In forward this torque is offset by the prop wash hitting the rudder and the rudder counter acting this torque, but in reverse the wash runs in the opposite direction and therefore the rudder loses it's effectiveness.

Twin prop boats deal with this torque issue by spinning the props in opposite directions.

The FH is a 27 prop boat... with three groups of nine props, each group arranged in a circle, and the three groups of circles all in a line. That line will get torqued as the three circles want to rotate.

So what imparts the torque within each engine? I'll leave that for you to answer... :-)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mhenderson on 12/29/2017 02:46 PM
What are the logistical factors involved in sourcing fuel, liquid oxygen, helium, and igniter hypergolics in the quantities required for a Falcon Heavy static fire test or launch? 

1) Many of these are no biggie to keep on hand.  I would expect RP1 fuel to be stable for storage, probably already on site for a static fire test. I would expect Helium to be stable, but prone to leakage losses.  Hypergolics are probably nasty to keep around (toxic and corrosive), but stable to store under the proper conditions.  Am I correct?  And do they fully tank all of these fluids during a static fire or do they "cheat" and just load a lesser amount sufficient for a brief firing? (I assume they top each of them off completely for a valid test run, but hey, you guys are the experts.)

2) My expectation is that LOX is both dangerous to handle and the most costly to store for any period of time. FH requires ~3X the amount of an F9 launch ... how far in advance of a static fire or launch does the supplier need to gear up production? Are those quantities substantial to a big liquid air supplier?  i.e. Is it even produced as a big special run or is it made in a more routine and steady fashion and stored? LOX has a boiling point of -297.3°F  = -183°C = 162°R = 90K, but SpaceX uses it at a much colder temperature to get the benefit of packing more oxidizer into the tanks.  Is it stored in bulk at the subcooled temperature?  Or do they store it at a temperature close to the boiling point and 'finish' it during the transfer/loading process?  Here's a NASA doc on subcooling on the run:
 https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050203875.pdf
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: zhangmdev on 12/29/2017 03:10 PM

First, can anyone tell if the TE is providing support to the top of the side boosters or are they only supported by the attachment to the center core?

My understand is there is no need for additional support. Like Delta 4 Heavy

http://www.spaceflightinsider.com/wp-content/uploads/2014/10/delta-iv-raise.jpg (http://www.spaceflightinsider.com/wp-content/uploads/2014/10/delta-iv-raise.jpg)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/29/2017 03:21 PM
There are arms on the TEL at the right height to support the boosters, see the pic in the post below.

https://forum.nasaspaceflight.com/index.php?topic=44376.msg1762298#msg1762298
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Paul_G on 12/29/2017 03:25 PM
What are the logistical factors involved in sourcing fuel, liquid oxygen, helium, and igniter hypergolics in the quantities required for a Falcon Heavy static fire test or launch? 

1) Many of these are no biggie to keep on hand.  I would expect RP1 fuel to be stable for storage, probably already on site for a static fire test. I would expect Helium to be stable, but prone to leakage losses.  Hypergolics are probably nasty to keep around (toxic and corrosive), but stable to store under the proper conditions.  Am I correct?  And do they fully tank all of these fluids during a static fire or do they "cheat" and just load a lesser amount sufficient for a brief firing? (I assume they top each of them off completely for a valid test run, but hey, you guys are the experts.)

2) My expectation is that LOX is both dangerous to handle and the most costly to store for any period of time. FH requires ~3X the amount of an F9 launch ... how far in advance of a static fire or launch does the supplier need to gear up production? Are those quantities substantial to a big liquid air supplier?  i.e. Is it even produced as a big special run or is it made in a more routine and steady fashion and stored? LOX has a boiling point of -297.3°F  = -183°C = 162°R = 90K, but SpaceX uses it at a much colder temperature to get the benefit of packing more oxidizer into the tanks.  Is it stored in bulk at the subcooled temperature?  Or do they store it at a temperature close to the boiling point and 'finish' it during the transfer/loading process?  Here's a NASA doc on subcooling on the run:
 https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050203875.pdf

1. I believe that tanks are fully loaded - essentially the hot fire is as if the rocket were launching, except they turn off the engines after x seconds, and don't release the hold downs. The hypergolic for engine startup come from the pad, not from tanks on the stage - the stage stored hypergolic are used for engine restarts after stage separation.

2. I read recently that the Lox is stored at regular lox temperatures, and chilled down as part of the loading process.

Rgds

Paul
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/29/2017 03:41 PM
Allow me to borrow some lines from the film Marooned:
-"Yes or no, will the bird fly?"
-"It'll fly..." ;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mn on 12/29/2017 03:43 PM
Quote
torque stresses

So I've seen this mentioned several times but I never saw an explanation.

Can someone please explain what this is about, and in particular why it would be more difficult on 3 cores vs 1 core.

(My simple mind would think that whatever stress is induced by the engines is local to the core, so you don't have 3 times the stress, you just have the same stress 3 times)
Generally speaking single propeller boats can only back down in one direction - this is because the propeller is rotating in one direction, thereby imparting a rotational torque on the boat (visualize a prop "walking" along the ground as it turns - that will show you the direction of the torque.) In forward this torque is offset by the prop wash hitting the rudder and the rudder counter acting this torque, but in reverse the wash runs in the opposite direction and therefore the rudder loses it's effectiveness.

Twin prop boats deal with this torque issue by spinning the props in opposite directions.

The FH is a 27 prop boat... with three groups of nine props, each group arranged in a circle, and the three groups of circles all in a line. That line will get torqued as the three circles want to rotate.

So what imparts the torque within each engine? I'll leave that for you to answer... :-)

Thanks for explanation, but I'm still stumped by the 1 vs 3 core?

Whatever torque issues are on one core they have obviously solved, so what happens when you have 3 cores side by side? as I said in my question: why is it a larger problem and not the same problem 3 times (with the same solution applied 3 times)?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/29/2017 03:50 PM
Because of the longer momentum arm the torque is applied on?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 12/29/2017 03:57 PM
Fast.  Barn to vertical.

And back to barn... one work day for fit-up*!

* assuming there isn't a second day planned in the future before roll-put for static fire.

Falcon Heavy on its way back to the HIF:

(https://i.redd.it/7usspmipbv601.jpg)

source (https://www.reddit.com/r/spaceporn/comments/7mugop/oc_falcon_heavy_back_to_horizontal_3024x4032/)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: abaddon on 12/29/2017 04:08 PM
The Falcon 9 single stick clearly doesn’t have any net torque when it’s flying (the very first Falcon 9 did have some unplanned roll immediately after liftoff).  I would assume the three boosters will be the same once flying.  However there might be torque in the startup sequence before the hold-down clamps are released.  I’d imagine any torque concerns are in this part of the timeline, not in flight.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/29/2017 04:12 PM
Thrust asymmetries during startup cause torques.  With 27 engines, more of the engines are further from the centerline, and so the worst-case torques are higher.  With FH there's the additional problem of torques applied across the long moment arm of the booster, causing the nose of the booster to move in relation to the core.

Since SpaceX is doing a staggered start, we know that there is some combination of startup transients that would "break things".  The staggered start is intended to ensure that the worst-possible worst-case transients can't add together in the bad way.  But of course the staggered start of all 27 engines hasn't been tested yet.  There are some unknown unknowns there that could cause the "break things" result.

And with respect to the "are the tanks full" question: the weight of the propellants in the tanks is part of what keeps the rocket on the ground during the static fire.  If you were to fire with lower fuel quantities, you'd either have to beef up the hold down to handle the greater thrust loads or (as they do in McGregor) fit a weighted "beanie cap" on top of the rocket to apply an equivalent gravity load.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: yokem55 on 12/29/2017 04:13 PM


I think the probability of success is pretty high, but not as high as a F9 of course.
I think 50-50 is about right.  That's what Elon suggested, if I recall correctly. 

There are certainly some untested aspects of this vehicle, especially base heating, max-q transonic aerodynamic stresses, pogo, etc.  History is a guide.  The first Delta 4 Heavy failed, as did three of the first six Titan IIIC missions and one of the first two Saturn 5 launches, though only one of those five combined failures was an outright Fail to Orbit.

As Elon said, we'll all be happy if this thing gets off the pad and over the Atlantic without mishap.  I believe that the odds of at least that happening are pretty good.

 - Ed Kyle

You might be able to add the first shuttle flight to that list.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mme on 12/29/2017 04:15 PM
...

Thanks for explanation, but I'm still stumped by the 1 vs 3 core?

Whatever torque issues are on one core they have obviously solved, so what happens when you have 3 cores side by side? as I said in my question: why is it a larger problem and not the same problem 3 times (with the same solution applied 3 times)?
If you watch the the liftoff of the first Falcon 9, it clearly rotates.  For a single stick, that's not really a big deal.  But now bolt three of them together and rather than rotate freely in space they will be torquing the connections.

https://www.youtube.com/watch?v=H6hYEqrP56I
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mn on 12/29/2017 04:21 PM
Now I remember where I first saw this mentioned:

https://www.nasaspaceflight.com/2017/11/spacex-aims-december-launch-falcon-heavy/

Quote
Due to thrust torque (a thrust-induced rotation) scenario that could destroy or severely damage the octawebs at the base of each Falcon core that house the Merlin 1D engines, the Falcon Heavy’s 27 engines will not be lit simultaneously like the Falcon 9 engines

So it seems we are dealing with an issue local to each core (worry about damage to the octaweb). so hence my question, why are 3 cores different than one core in this respect.

Suppose we stood 3 cores side by side without any hardware connecting them (obviously would need 3 TELs) would igniting them be different than usual?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: NX-0 on 12/29/2017 04:25 PM

If you watch the the liftoff of the first Falcon 9, it clearly rotates.  For a single stick, that's not really a big deal.  But now bolt three of them together and rather than rotate freely in space they will be torquing the connections.

https://www.youtube.com/watch?v=H6hYEqrP56I

Waves and waves of nostalgia there.
F9 V1.0 is such a different animal from what we are seeing now.
'stubby' looking even, especially with no legs

3x3 engines looks freaky, now.
Did Octoweb help with some of the roll issues?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mn on 12/29/2017 04:28 PM
...

Thanks for explanation, but I'm still stumped by the 1 vs 3 core?

Whatever torque issues are on one core they have obviously solved, so what happens when you have 3 cores side by side? as I said in my question: why is it a larger problem and not the same problem 3 times (with the same solution applied 3 times)?
If you watch the the liftoff of the first Falcon 9, it clearly rotates.  For a single stick, that's not really a big deal.  But now bolt three of them together and rather than rotate freely in space they will be torquing the connections.

https://www.youtube.com/watch?v=H6hYEqrP56I

The issue they are worried about is during ignition, not during flight.

(and we've seen many launches since then, I don't think they have a problem here)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Gotorah on 12/29/2017 04:46 PM
The gimbal of the engines is fully capable of eliminating or inducing any roll wanted or unwanted.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/29/2017 05:04 PM
I'm not concerned by any flight control guidance authority issues, just potential pneumatics and unlatch hangs at  booster sep...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/29/2017 05:10 PM
I think the probability of success is pretty high, but not as high as a F9 of course.
I think 50-50 is about right.  That's what Elon suggested, if I recall correctly. 

There are certainly some untested aspects of this vehicle, especially base heating, max-q transonic aerodynamic stresses, pogo, etc.  History is a guide.  The first Delta 4 Heavy failed, as did three of the first six Titan IIIC missions and one of the first two Saturn 5 launches, though only one of those five combined failures was an outright Fail to Orbit.

As Elon said, we'll all be happy if this thing gets off the pad and over the Atlantic without mishap.  I believe that the odds of at least that happening are pretty good.

 - Ed Kyle

I'm amazed that people continue to not understand the expectations game that Elon plays - all the time.

If they truly think that FH only has a 50% chance of succeeding, they are not going to launch. Period. They are going to want to be a lot more confident than that.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: BeamRider on 12/29/2017 05:26 PM
Due to thrust torque (a thrust-induced rotation)...

I believe the torque mentioned is around a horizontal axis. A single stick might use an asymmetric engine ignition sequence without overstressing its own octaweb. But placed side by side, the asymmetric startup thrusts could overstress one or both webs. Now think of that happening on both sides of the center booster web simultaneously... complex.

I thought the problem would actually be in any mismatch in the overall thrust startup of the two side boosters, which could result (say) in the links on one side of the center booster being lift-loaded before the other. Could cause a center tube or link failure, I would imagine. Fireball.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: abaddon on 12/29/2017 05:27 PM
If you watch the the liftoff of the first Falcon 9, it clearly rotates.  For a single stick, that's not really a big deal.  But now bolt three of them together and rather than rotate freely in space they will be torquing the connections.
I'm sure that would be a problem if SpaceX was trying to launch three of the very first Falcon 9 1.0 rockets together... given that none of the 45 subsequent Falcon 9's have done this, I'd have to think it isn't a factor today.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/29/2017 05:29 PM
Due to thrust torque (a thrust-induced rotation)...

I believe the torque mentioned is around a horizontal axis. A single stick might use an asymmetric engine ignition sequence without overstressing its own octaweb. But placed side by side, the asymmetric startup thrusts could overstress one or both webs. Now think of that happening on both sides of the center booster web simultaneously... complex.

Yep, those are all potential failure points. BUT... Given that we have seen absolutely ZERO evidence of any torque induced roll in any flight after F9 flight 1, I think they are completely aware and it will not be an issue that I have any concerns about.

I thought the problem would actually be in any mismatch in the overall thrust startup of the two side boosters, which could result (say) in the links on one side of the center booster being lift-loaded before the other. Could cause a center tube or link failure, I would imagine. Fireball.

And this is why they are going to be doing hotfires of the 3 cores together (perhaps more than one), and why they have hold-downs that won't release FH unless the thrust is good on all cores.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/29/2017 05:39 PM
Due to thrust torque (a thrust-induced rotation)...

I believe the torque mentioned is around a horizontal axis. A single stick might use an asymmetric engine ignition sequence without overstressing its own octaweb. But placed side by side, the asymmetric startup thrusts could overstress one or both webs. Now think of that happening on both sides of the center booster web simultaneously... complex.

I thought the problem would actually be in any mismatch in the overall thrust startup of the two side boosters, which could result (say) in the links on one side of the center booster being lift-loaded before the other. Could cause a center tube or link failure, I would imagine. Fireball.
My thoughts are that it would then result in a pad abort shutdown and then safing the vehicle...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: topopesto on 12/29/2017 05:49 PM
I think that this mission it's be fine without problem.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mhenderson on 12/29/2017 06:12 PM
How much heavier is this experimental FH than future commercial versions? 

The first prototype is likely to be heavier than future vehicles because of higher margins allowed for unknown stresses, the ongoing march of materials technology, and the use of extra instrumentation on the first flight that becomes irrelevant after a few flight experiences.

The first space shuttle to reach orbit (Columbia) weighed about 4000 kg more than its successors.  Part of this (~500 kg) was due to instrumentation used on the first four test flights and not needed on successive flights.  Columbia was "put on a diet" and updated to replace gear with lighter advanced materials / designs, or to remove those unnecessary instruments.  https://spaceflightnow.com/shuttle/features/000414overhaul/weightloss.html

In this case, much of the center FH booster core, the interstage and upper stage have been refined through dozens of launches of single stick rockets.  The outer cores on this vehicle are "block 3" (or whatever the heck they are calling them this week) cores.

SpaceX has also announced that they intend to freeze Falcon and redirect resource to BFR development, leaving less manpower for successive improvements to FH. 

So, how close is this beast to the "final" FH?   

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/29/2017 06:29 PM
So, how close is this beast to the "final" FH?

F9 and FH will continue to evolve, so I'm not sure what you are asking for. (For example, every single F9 that has launched has likely had some unique tweak, this is common)

But I do not expect any significant mass changes. Sure some mass might be removed for added efficiency, but mass might also be added for recovery hardware. And FH has so much performance margin that there isn't much need for reducing mass.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 12/29/2017 07:01 PM
I think the probability of success is pretty high, but not as high as a F9 of course.
I think 50-50 is about right.  That's what Elon suggested, if I recall correctly. 

There are certainly some untested aspects of this vehicle, especially base heating, max-q transonic aerodynamic stresses, pogo, etc.  History is a guide.  The first Delta 4 Heavy failed, as did three of the first six Titan IIIC missions and one of the first two Saturn 5 launches, though only one of those five combined failures was an outright Fail to Orbit.

As Elon said, we'll all be happy if this thing gets off the pad and over the Atlantic without mishap.  I believe that the odds of at least that happening are pretty good.

 - Ed Kyle

I'm amazed that people continue to not understand the expectations game that Elon plays - all the time.

If they truly think that FH only has a 50% chance of succeeding, they are not going to launch. Period. They are going to want to be a lot more confident than that.

If you take Ed's tradition definition of failure, which includes inaccurate orbital insertions at the very least, then 50-50 is not grotesque (though still pessimistic IMO).

I'd say the odds for a picture-perfect mission, correct trajectory, two good landings - that's 50-50.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: biosehnsucht on 12/29/2017 07:30 PM
Re: start up torque

don't forget that there's more hold downs on the FH than the F9, so there's more paths for any torque to have the force removed than just via the octowebs. It should also be trivial to design the startup sequence to balance the torque across a given core, and with only a few engines starting at a time, the maximum imbalance across all cores even if there are initial thrust variations before thrust settles for a given set of engines starting, should be trivial compared to a full F9 startup.

I think that torque during startup is a non-issue, and for launch mainly because they'll wait until thrust is balanced out before launching (and abort otherwise).

I'd be far more concerned with aerodynamic and thrust (in a non-torque sense) loads and the separation sequence.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: BeamRider on 12/29/2017 07:45 PM
Ideally you are correct. I suppose it depends on the precise engineering of the hold-downs and structure as to whether any torques or displacements can exist prior to release, and be transmitted from one core to another. Hopefully the answer is NO.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mme on 12/29/2017 07:50 PM
If you watch the the liftoff of the first Falcon 9, it clearly rotates.  For a single stick, that's not really a big deal.  But now bolt three of them together and rather than rotate freely in space they will be torquing the connections.
I'm sure that would be a problem if SpaceX was trying to launch three of the very first Falcon 9 1.0 rockets together... given that none of the 45 subsequent Falcon 9's have done this, I'd have to think it isn't a factor today.
We had pages of "what torsional forces?" and I was trying to provide a clear example where one could visualize the forces acting on a single booster. The fact that you don't "see" the rotation after launch does not mean there are not extreme torsional forces during start up nor that there are not small constant corrections in flight.

With the F9 as you gimbal the engines any vectoring differences go into the single octaweb.  With the FH you have the sum of the vectors going into the octaweb of each booster and then the resulting forces being transmitted into the attachment points of the octawebs.

The GNC needs to vector/throttle 27 engines in a way that controls a rocket as a whole and it needs to do it in a way that does not over-stress the attachment points. Depending on the information available to the GNC that may be trickier than it sounds.

I have no doubt that SpaceX has done their very best to model all of this. I am optimistic that this mission will succeed. But I think people are over simplifying the dampening and feedback effects of bolting three really powerful rockets together.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Karloss12 on 12/29/2017 09:08 PM
I'm amazed that people continue to not understand the expectations game that Elon plays - all the time.

If they truly think that FH only has a 50% chance of succeeding, they are not going to launch. Period. They are going to want to be a lot more confident than that.

How do you suggest they become more confident?  You can do Engineering calculations until the cows come home, however they will only ever get you so far.  Sometimes you just have to be brave to go for it and learn from a 50:50 failure.  It's not like the Block 3 cores are going to be used again if it is a success.
The cores operating independently have now been proven with F9 launches, so I don't see any issues with individual cores failing.
As there is a very light payload, the axial forces will be low on the centre core, therefore I don't expect the centre core to fail.
In the side cores, everything above the octaweb is over designed as they are designed to lift a payload positioned on top of them.  For FH, the side cores are lifting the centre core from the base.
I think the primary purpose of the FH demo launch will be to test the core connection mechanisms during lift off, flight and separation under light loading.
If they can confirm that then additional weight will be added for the next test.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/29/2017 09:31 PM
They are doing a staggered start. They would not be adding that complexity if there weren't a startup situation that would cause a Bad Day otherwise.  So some combination of ignition delays and thrust asymmetries can overtorque the octowebs. The only question is whether the staggered start is sufficient to address the issue, or whether we will find out the hard way about another bad coupling mode between the engines.  With N engines, there are N^2/2 possible interactions between them...

I agree with others that any bad effect here would most likely be found during static fire and would be resolved before the hold downs were released.  But it doesn't seem impossible to me that the first all-up static fire will torque the FH in such a way that they need to stand down and send the FH back to the shed to repair/replace components. I'm sure SpaceX has done all the modelling possible to ensure this doesn't occur.  But there are unknown unknowns... and also always the possibility of human error, as in the test stand failure that resulted in damaging 8 of 9 engine bells at McGregor.  Murphy is always fond of discovering ways to do "impossible" things.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Oersted on 12/29/2017 09:41 PM
Things can happen but I don’t think there are many unknowns and that SpaceX will be conservative on this first one, as much as they can be anyway.

SpaceX conservative?

Flying with just one side booster would be the conservative choice. Going all out with two side boosters? Now that's gutsy.







;-)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Alpha Control on 12/29/2017 10:20 PM
I have a question that I don't think I've seen addressed yet:  Has a 2nd Falcon Heavy core been produced at this point?  As we know the FH core is considerably different from the standard F9, and I'm assuming they take longer to build than a standard core.  I haven't seen a mention of the status of a second core at this point in time.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: John Alan on 12/29/2017 10:41 PM
I have a question that I don't think I've seen addressed yet:  Has a 2nd Falcon Heavy core been produced at this point?  As we know the FH core is considerably different from the standard F9, and I'm assuming they take longer to build than a standard core.  I haven't seen a mention of the status of a second core at this point in time.

It seems widely accepted here at NSF, that the next FH flight on the manifest (STP-2) mid year would be using all new build 'block 5' class hardware...
My opinion is to agree with that idea, as it's a demo for the US Air Force... with payloads provided by them...
So it's likely that these three boosters are soon to be started on the assy lines...
More likely after this first flight... and using the data and post flight inspections to guide any changes needed...
The other thought was after this flight mid year... SpaceX would reuse these three boosters for the next two FH launches (assuming no losses)...
That said... I have no linkage or proof to back up these statements...  ???
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FutureMartian97 on 12/30/2017 12:52 AM
Are they going to take the fairing off for the static fire? It seems like a waste for this flight if they do. I mean, the payload is already attached, and its not a $100 million satellite, and it would be good to get vibration data on the full completed vehicle.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: R.Simko on 12/30/2017 02:04 AM
Perhaps it's time we had a poll.
Example:
1. Flight complete success, with all 3 first stages landing intact.
2. Makes it past first stage separation and lands at least 2 first stages.
3. Makes it past max Q.
4. Does not make max Q.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/30/2017 02:20 AM
Perhaps it's time we had a poll.
Example:
1. Flight complete success, with all 3 first stages landing intact.
2. Makes it past first stage separation and lands at least 2 first stages.
3. Makes it past max Q.
4. Does not make max Q.

There is already a poll in the poll section of the forum.

Edit/Lar: Indeed:  http://forum.nasaspaceflight.com/index.php?topic=44559
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 12/30/2017 02:47 AM
There are certainly some untested aspects of this vehicle, especially..... pogo.....  History is a guide.

I don't think "torque", or force of rotation around an axis, is the right word or focus. Where is everyone seeing so many spinning parts that can go wrong?

From everything I've Googled today, pogo oscillations appear to be the real risk, up and down variations in thrust & LOX & fuel flow. They brought down the 4th & final 30-engine N-1 launch, and have a long history of plaguing US launches as well. They also have a long history of mitigation by various kinds of engineering, the latest written up by our own Philip Sloss just this month (https://www.nasaspaceflight.com/2017/12/rs-25-next-phase-testing-stennis-hot-fire/#more-53504), a 3D-printed POGO Suppression Accumulator built by Aerojet Rocketdyne for NASA's Space Launch System R-25 engines. In the past NASA instituted a safety level of G forces to be tolerated by such oscillations, +/-0.25G (https://www.popsci.com/how-little-vibrations-break-big-rockets).

Here's one description related to the 4th N-1 launch:

Quote
Pogo oscillation is exactly what it sounds like – a violent up-and-down motion that could make anybody sick, but makes rockets really really sick. It results from a variation in thrust from different engines, and with thirty unreliable ones, you can get a lot of variation. Once it starts, it's very hard to correct, as the variable acceleration leads to variable fuel pump pressures, which leads to more variables acceleration, and so on and so on until eventually you match the vehicle's resonance frequency and vibrate the whole thing to death.
https://jalopnik.com/this-insane-rocket-is-why-the-soviet-union-never-made-i-1448356326
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Grandpa to Two on 12/30/2017 03:15 AM
There are certainly some untested aspects of this vehicle, especially..... pogo.....  History is a guide.

I don't think "torque", or force of rotation around an axis, is the right word or focus. Where is everyone seeing so many spinning parts that can go wrong?

From everything I've Googled today, pogo oscillations appear to be the real risk, up and down variations in thrust & LOX & fuel flow. They brought down the 4th & final 30-engine N-1 launch, and have a long history of plaguing US launches as well. They also have a long history of mitigation by various kinds of engineering, the latest written up by our own Philip Sloss just this month (https://www.nasaspaceflight.com/2017/12/rs-25-next-phase-testing-stennis-hot-fire/#more-53504), a 3D-printed POGO Suppression Accumulator built by Aerojet Rocketdyne for NASA's Space Launch System R-25 engines. In the past NASA instituted a safety level of G forces to be tolerated by such oscillations, +/-0.25G (https://www.popsci.com/how-little-vibrations-break-big-rockets).

Here's one description related to the 4th N-1 launch:

Quote
Pogo oscillation is exactly what it sounds like – a violent up-and-down motion that could make anybody sick, but makes rockets really really sick. It results from a variation in thrust from different engines, and with thirty unreliable ones, you can get a lot of variation. Once it starts, it's very hard to correct, as the variable acceleration leads to variable fuel pump pressures, which leads to more variables acceleration, and so on and so on until eventually you match the vehicle's resonance frequency and vibrate the whole thing to death.
https://jalopnik.com/this-insane-rocket-is-why-the-soviet-union-never-made-i-1448356326

I also was researching pogo and believe it could be the greatest risk to this first flight. It’s impossible to check until the Heavy is running. Maybe we’ll see a much longer static fire so they can get an idea of how the vibrations affect the rocket. Once airbourne will come the real test for pogo. I’m glad Elon is going to keep thrust down to 92% for this flight.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: georgegassaway on 12/30/2017 04:16 AM
Hmm, the historic examples of Pogo were with non-throttled engines (AFAIK). Makes me wonder if the rate of throttle response might be fast enough to reduce some Pogo effect., if programmed to do so.  But I do not know anything about the throttle response rate. 

Ideally of course they want a design/physical fix for Pogo as the primary solution, regardless.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/30/2017 04:16 AM
I see very little (if any) risk for POGO for FH, since they are flying the same stages as F9. Same engines, same tank lengths. POGO - if present - will show up in early launches.

All this talk of possible failure points - one more dramatic than the next - starts to border on concern trolling, IMO. “Surely SpaceX has not thought of *this*?”
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Surfdaddy on 12/30/2017 04:23 AM
I see very little (if any) risk for POGO for FH, since they are flying the same stages as F9. Same engines, same tank lengths. POGO - if present - will show up in early launches.

All this talk of possible failure points - one more dramatic than the next - starts to border on concern trolling, IMO. “Surely SpaceX has not thought of *this*?”

I'm no expert, but wouldn't the pogo risk be increased because of potential flexibilities in the triple stage cluster that could impart motions/resonances and vibrations and flexing that would NOT be the same as the relative simplicity of single boosters?

Put simply. I disagree with the assumption that "since we know the F9 works fine, clustering 3 together will work fine without those problems as well".
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vaporcobra on 12/30/2017 04:52 AM
If the question starts with "I'm no expert...," the answer is almost invariably, "Yes, dozens of highly skilled and experienced engineers considered it and implemented the best possible solution over the course of many iterations of analysis, modeling, and testing."
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/30/2017 05:20 AM
Emily Lakdawalla points out that the FH demo launch is too early for an optimal earth-mara trajectory:
https://twitter.com/elakdawalla/status/946941586373451776

Can someone with the technical chops compute if FH has to capability to put a roadster-sized payload arbitrarily close to Mars (ie, for purposes of computation, on a path impacting Mars) even if launched mid-January?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 12/30/2017 05:47 AM
Emily Lakdawalla points out that the FH demo launch is too early for an optimal earth-mara trajectory:
https://twitter.com/elakdawalla/status/946941586373451776

Can someone with the technical chops compute if FH has to capability to put a roadster-sized payload arbitrarily close to Mars (ie, for purposes of computation, on a path impacting Mars) even if launched mid-January?

It’s not going to Mars. It’s going out to Mars orbit. It will get close to Mars *eventually*, but the launch window(s) are not as rare as she thinks.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: pargoo on 12/30/2017 06:05 AM
So...let me get this strait.  We have the most eagerly-awaited rocket roll-out in decades, and all we get are long-distance shots and no up-close hi-res's from SpaceX?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vaporcobra on 12/30/2017 06:05 AM
Yeah, judging from some coincidentally accurate porkchop plots and a few articles, Roadster can certainly make it to a rather close encounter with Mars, it just might take anywhere from a 12-24 month coast period to get there. Rather improbable that S2 can remain functional over that period without some intense modifications (and solar panels).

Edit: Found a very convenient table of trajectory calculations over the 2017-2018 period and they look quite promising. Jan 2018 is certainly less efficient than the May that Emily mentions, but it's a minor improvement compared to 2017 (500-900 days, 5000-8000 m/s dV). The random forum user's calculations show that a launch to TMI from LEO in Jan 2018 would have a coast period of ~260 days and a dV cost of ~4500 m/s.

InSight's May 2018 launch will have a coast of ~250 days with a dV cost of ~3550 m/s.

https://www.orbiter-forum.com/showthread.php?t=37063
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vaporcobra on 12/30/2017 06:06 AM
So...let me get this strait.  We have the most eagerly-awaited rocket roll-out in decades, and all we get are long-distance shots and no up-close hi-res's from SpaceX?

Patience, young Padawan.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 12/30/2017 06:21 AM
Emily Lakdawalla points out that the FH demo launch is too early for an optimal earth-mara trajectory:
https://twitter.com/elakdawalla/status/946941586373451776

Can someone with the technical chops compute if FH has to capability to put a roadster-sized payload arbitrarily close to Mars (ie, for purposes of computation, on a path impacting Mars) even if launched mid-January?

My search results: It could do a flyby of Mars (https://trajbrowser.arc.nasa.gov/traj_browser.php?chk_maxMag=on&maxMag=25&chk_maxOCC=on&maxOCC=4&chk_target_list=on&target_list=Mars&mission_class=oneway&mission_type=flyby&LD1=2018&LD2=2019&maxDT=3.0&DTunit=yrs&maxDV=14.0&min=DV&wdw_width=-1&submit=Search#a_load_results) (view the 1st one with a Jan departure date [C3=20.1]) with a launch opportunity on January 2nd.  So, I guess, given the actual, likely date being mid-month, it probably still could if the payload had the ability to do some course correction (which it doesn't).  LSP's elvperf calculator says that a Falcon Heavy (with recovery) can launch 2960kg to the C3 that trajectory would require.  The roadster had a curb weight of 1305kg (though this one may have been modified, either for Elon's driving pleasure or in the effort to turn it into a spacecraft).  So, that is well within the capability of FH even if you added some weight to enable trajectory maneuvers, etc.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ben the Space Brit on 12/30/2017 06:53 AM
I don't think that there is any realistic prospect of SpaceX confirming actively that the roadster gets to its destination orbit. All they will be able to do is monitor the second stage for as long as possible to confirm its trajectory. All they'll ever be able to say is: "With a high degree of confidence..."
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: pargoo on 12/30/2017 10:32 AM
OK, I guess it's coming up to the New Year, but still..
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Oersted on 12/30/2017 11:14 AM
So...let me get this strait.  We have the most eagerly-awaited rocket roll-out in decades, and all we get are long-distance shots and no up-close hi-res's from SpaceX?

To the general public it would look weird with a headline saying "the rocket went to the launch pad and was then carted back into its hangar again". They'll roll out the PR train when it comes out for launch.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Herb Schaltegger on 12/30/2017 12:45 PM
I don't think that there is any realistic prospect of SpaceX confirming actively that the roadster gets to its destination orbit. All they will be able to do is monitor the second stage for as long as possible to confirm its trajectory. All they'll ever be able to say is: "With a high degree of confidence..."

Doppler tracking and telemetry from the stage itself within milliseconds of the S2 injection burn cutoff will tell them EXACTLY what the final trajectory will be, absent any unplanned venting events (debris impact or valve failure leading to overpressure). They don't need an active second stage, broadcasting for days, weeks or months to "follow" the stage and watch.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: clongton on 12/30/2017 01:13 PM
I know I am not going to make any friends by saying this but it needs to be said.

I would majorly hate to be a member of the generation that just can't stand to wait until it [whatever "it" may be] actually happens. I get the impression that they would never be able to stand the wait time of several YEARS while a probe makes its way to Jupiter, Saturn, Uranus, Neptune, Pluto or the Ort cloud. Their heads would explode. Try launching a probe like that knowing that you yourself may very well not live long enough to see it arrive and that children who are in 4th grade at launch date would likely be the scientists that would monitor and record the arrival. Do you have the patience for that?

Jeepers people. The solar system isn't your back yard that can be crossed in a leap and a bound.
SpaceX will provide photographs when it wants to and not one second before - they don't owe any of us a thing.
Falcon Heavy will launch when it is ready. - Give it a rest and have a cup of tea or coffee or latte-mocha-chi-whatever.
Chill. It will happen when it happens.
THIS site will be the first to let you know it's happening so just stay tuned and quit complaining.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: SimonFD on 12/30/2017 01:21 PM
I know I am not going to make any friends by saying this but it needs to be said.

I would majorly hate to be a member of the generation that just can't stand to wait until it [whatever "it" may be] actually happens. I get the impression that they would never be able to stand the wait time of several YEARS while a probe makes its way to Jupiter, Saturn, Uranus, Neptune, Pluto or the Ort cloud. Their heads would explode. Try launching a probe like that knowing that you yourself may very well not live long enough to see it arrive and that children who are in 4th grade at launch date would likely be the scientists that would monitor and record the arrival. Do you have the patience for that?

Jeepers people. The solar system isn't your back yard that can be crossed in a leap and a bound.
SpaceX will provide photographs when it wants to and not one second before - they don't owe any of us a thing.
Falcon Heavy will launch when it is ready. - Give it a rest and have a cup of tea or coffee or latte-mocha-chi-whatever.
Chill. It will happen when it happens.
THIS site will be the first to let you know it's happening so just stay tuned and quit complaining.

Ah, the impatience of youth, assisted by a culture hell bent on instant gratification, topped by the photos-or-it-didn't-happen dogma.

 ;) 8)

Just in case that wasn't clear - I agree with Chuck
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 12/30/2017 01:24 PM
I know I am not going to make any friends by saying this but it needs to be said.

I would majorly hate to be a member of the generation that just can't stand to wait until it [whatever "it" may be] actually happens. I get the impression that they would never be able to stand the wait time of several YEARS while a probe makes its way to Jupiter, Saturn, Uranus, Neptune, Pluto or the Ort cloud. Their heads would explode. Try launching a probe like that knowing that you yourself may very well not live long enough to see it arrive and that children who are in 4th grade at launch date would likely be the scientists that would monitor and record the arrival. Do you have the patience for that?

Jeepers people. The solar system isn't your back yard that can be crossed in a leap and a bound.
SpaceX will provide photographs when it wants to and not one second before - they don't owe any of us a thing.
Falcon Heavy will launch when it is ready. - Give it a rest and have a cup of tea or coffee or latte-mocha-chi-whatever.
Chill. It will happen when it happens.
THIS site will be the first to let you know it's happening so just stay tuned and quit complaining.

Ah, the impatience of youth, assisted by a culture hell bent on instant gratification, topped by the photos-or-it-didn't-happen dogma.

 ;) 8)

The flip side is waiting patiently, like an 'adult,' for decades -- all the while knowing deep down that it will never happen. 

Seems to me, it takes a healthy portion of each to get something useful done.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/30/2017 01:30 PM


Yeah, judging from some coincidentally accurate porkchop plots and a few articles, Roadster can certainly make it to a rather close encounter with Mars, it just might take anywhere from a 12-24 month coast period to get there.

What's with the asymptote in that porkchop plot?  It seems like the required dV around Jan 15 is actually extremely sensitive to the exact date selected.  Is that just an artifact of some other choice made in the plot, or is there an actual orbital mechanics reason why Jan 15 would be so much worse than Jan 1?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: woods170 on 12/30/2017 01:50 PM
So...let me get this strait.  We have the most eagerly-awaited rocket roll-out in decades, and all we get are long-distance shots and no up-close hi-res's from SpaceX?

Patience, young Padawan.

Yeah, I keep telling Pargoo that but he just won't listen. Stubborn he is. ;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: daveklingler on 12/30/2017 02:07 PM
So...let me get this strait.  We have the most eagerly-awaited rocket roll-out in decades, and all we get are long-distance shots and no up-close hi-res's from SpaceX?

Patience, young Padawan.

Yeah, I keep telling Pargoo that but he just won't listen. Stubborn he is. ;)

Launch it.  :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/30/2017 02:28 PM
Photos and video are more than likely being taken for engineering documentation, just not released...They have other priorities at this time which also happens to be in the middle of a holiday week... Keep calm, Go SpaceX...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: the_other_Doug on 12/30/2017 04:31 PM
Just a quick question -- I've seen a lot of images of FH being brought out to the pad, erected, then brought back down to horizontal.  But nothing showing that it has been put back in the HIF.

Is it being left outside and on the pad?  If so, should we expect a couple more test erections and de-erections?

:)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mme on 12/30/2017 04:36 PM
So...let me get this strait.  We have the most eagerly-awaited rocket roll-out in decades, and all we get are long-distance shots and no up-close hi-res's from SpaceX?

Patience, young Padawan.

Yeah, I keep telling Pargoo that but he just won't listen. Stubborn he is. ;)
Someone over in a. competitor’s thread just called SX risk averse. :D

I think launches are addictive. The more we get, the more we want.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: atsf90east on 12/30/2017 05:15 PM
I can't help but wonder what the excitement and comments would have been like if the internet had existed in May of 1966 when Saturn V 500F was rolled out to Pad 39A for fit checks.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 12/30/2017 05:23 PM
I see very little (if any) risk for POGO for FH, since they are flying the same stages as F9. Same engines, same tank lengths. POGO - if present - will show up in early launches.

All this talk of possible failure points - one more dramatic than the next - starts to border on concern trolling, IMO. “Surely SpaceX has not thought of *this*?”

According to what I Googled, pogo was successfully mitigated throughout the Shuttle launch program with only 3 engines each but had a way of creeping back into the Apollo program in spite of mitigation, all the way through Apollo 17.

I doubt people here think they are pointing out anything SpaceX people don't already know, but instead are trying to figure out their extra concerns based on the scary odds Elon has given the launch attempt, beyond the lists Chris Gebhardt has presented in his single core static fire articles.

The majority of concerns are probably even more innocuous than mn's suggestion of issues discretely times 3 in place of 3 times the issues. There might be one valve in one core that needs replacing as there has been in the past. 

I'm amazed that people continue to not understand the expectations game that Elon plays - all the time.

If they truly think that FH only has a 50% chance of succeeding, they are not going to launch. Period. They are going to want to be a lot more confident than that.

The 1st statement is true to some extent. I've only witnessed his giving the same odds for the 1st landing attempt, and even though when asked in a Reddit AMA shortly in advance how he had calculated those odds he admitted they were completely estimated, look what happened then.

However, the 2nd statement I tend to agree with, and since Elon gave the 50/50 odds some months ago, and there are obviously many who trust his instincts, some of those same people have probably done additional checks & corrections & increased the odds of success in the interim.

The biggest indication for observers of the odds of success or failure closer to launch time is going to be the range of the hazard area, and I would NOT want to be in the USAF's position of determining that. I won't go as far as quoting the aftermath of the historically largest pad explosion, but suffice it to say windows were blown off buildings as far away as 35 & 40 km (~22 & 25 mi), and for those feeling strong enough to read more my source is http://www.russianspaceweb.com/n1_5l.html.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FutureSpaceTourist on 12/30/2017 05:49 PM
Just a quick question -- I've seen a lot of images of FH being brought out to the pad, erected, then brought back down to horizontal.  But nothing showing that it has been put back in the HIF.

Is it being left outside and on the pad?  If so, should we expect a couple more test erections and de-erections?

:)

Now have confirmation it’s back in the HIF:
http://forum.nasaspaceflight.com/index.php?topic=44376.msg1765919#msg1765919 (http://forum.nasaspaceflight.com/index.php?topic=44376.msg1765919#msg1765919)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RocketLover0119 on 12/30/2017 06:17 PM
According to Chris B's (awesome) article, we currently ( but don't be shocked if this slips) have a SF targeted for the 6th with a window opening on the 15th. And also what time of day is it going to be?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Heinrich on 12/30/2017 06:24 PM
I knew the engines were going to be started 2 at a time. But I always thought this meant at each core. (So in total 6 at a time, 5 steps). Todays article by Chris says:
"It is understood that two Merlin 1D engines will be lit simultaneously followed by the next two… and so on until all 27 are up and running, providing a controlled ramp up to full power for the business end of the vehicle."
Which to me suggests only 2 at a time, so 14 steps in total.


Can someone clarify?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dnavas on 12/30/2017 06:46 PM
I know I am not going to make any friends by saying this but it needs to be said.

I would majorly hate to be a member of the generation that just can't stand to wait until it [whatever "it" may be] actually happens.
The flip side is waiting patiently, like an 'adult,' for decades -- all the while knowing deep down that it will never happen. 

I think the flip side is getting off your own backside and doing something about it.  Either you're waiting to be a witness, or you're pressing to be a participant.

Most of us here are witnesses, and my counsel would be to find many things to watch in between the times when you work.  We've got a launch on the 4th, and a static fire on the 6th.  Then we wait to see what the outcome of that is (from launch mid-month to another pad rebuild .. ).  While we wait, there's CES the week after with cameras (to photograph launches) and maybe even processors (to edit the footage).  And then, hopefully, a launch....  Not sure I understand where the impatience comes from -- there's a LOT going on, especially in this corner of the world.  Heck, the last launch I watched was actually two -- JAXA and SpaceX, practically at the exact same time!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Rocket Science on 12/30/2017 06:49 PM
I see very little (if any) risk for POGO for FH, since they are flying the same stages as F9. Same engines, same tank lengths. POGO - if present - will show up in early launches.

All this talk of possible failure points - one more dramatic than the next - starts to border on concern trolling, IMO. “Surely SpaceX has not thought of *this*?”
Over the years they though up a "lot of things" that went off with a "bang"... Flight testing is not just to uncover what you haven't thought of but also to "confirm" what you have by building confidence in the modeling... So please don't worry too much by trying to be the "SpaceX thought police"...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jpo234 on 12/30/2017 07:33 PM



I think launches are addictive. The more we get, the more we want.

There will be a saturation point when the Starlink build-up goes into full swing.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: tvg98 on 12/30/2017 07:39 PM



I think launches are addictive. The more we get, the more we want.

There will be a saturation point when the Starlink build-up goes into full swing.

Assuming most if not all are broadcast to us of course. If launches become too numerous and common then I can see them only broadcasting special launches such as Crew launches, FH launches, etc. But anyway, back to Falcon Heavy.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: archae86 on 12/30/2017 07:53 PM
Larger versions
In the post (on the update thread) I'm referencing, the posted image of the 27-Merlin business end (FH-mated3.jpg) has four curious objects, a pair between each side booster and the main.  A colleague on another forum speculated that they might be damping devices, and I speculate they might be actuators in the separation system.  I've cropped a closeup from the cited photo and am attaching it as FH_Whazzat_0.jpg. 

Does anyone know what they are, or care to guess?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/30/2017 08:34 PM
Larger versions
In the post (on the update thread) I'm referencing, the posted image of the 27-Merlin business end (FH-mated3.jpg) has four curious objects, a pair between each side booster and the main.  A colleague on another forum speculated that they might be damping devices, and I speculate they might be actuators in the separation system.  I've cropped a closeup from the cited photo and am attaching it as FH_Whazzat_0.jpg. 

Does anyone know what they are, or care to guess?

[GUESS]

I'd guess it's a pusher, while the other attachment points just hold it in place. Once they let go these would push the booster away.

[/GUESS]
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 12/30/2017 08:37 PM



I think launches are addictive. The more we get, the more we want.

There will be a saturation point when the Starlink build-up goes into full swing.

If you're near SFO, look up the Elephant Bar, located on the shoreline in line with the threshold for runway 28, and watch them land in pairs as you get the Seared Ahi-Tuna and a Jack Daniels.

If THAT doesn't get old, I can't see how a few launches per day would.  :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jim on 12/30/2017 08:56 PM
So...let me get this strait.  We have the most eagerly-awaited rocket roll-out in decades, and all we get are long-distance shots and no up-close hi-res's from SpaceX?

Not decades.  There were many others, just not hyped
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: old_sellsword on 12/30/2017 09:11 PM
Larger versions
In the post (on the update thread) I'm referencing, the posted image of the 27-Merlin business end (FH-mated3.jpg) has four curious objects, a pair between each side booster and the main.  A colleague on another forum speculated that they might be damping devices, and I speculate they might be actuators in the separation system.  I've cropped a closeup from the cited photo and am attaching it as FH_Whazzat_0.jpg. 

Does anyone know what they are, or care to guess?

They are the pneumatic pusher mechanisms. Two for each booster’s octaweb.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jim on 12/30/2017 09:14 PM
Larger versions
In the post (on the update thread) I'm referencing, the posted image of the 27-Merlin business end (FH-mated3.jpg) has four curious objects, a pair between each side booster and the main.  A colleague on another forum speculated that they might be damping devices, and I speculate they might be actuators in the separation system.  I've cropped a closeup from the cited photo and am attaching it as FH_Whazzat_0.jpg. 

Does anyone know what they are, or care to guess?

not dampers.  no need for such.  It is the sep system
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 12/30/2017 09:26 PM
I know I am not going to make any friends by saying this but it needs to be said.

I would majorly hate to be a member of the generation that just can't stand to wait until it [whatever "it" may be] actually happens. I get the impression that they would never be able to stand the wait time of several YEARS while a probe makes its way to Jupiter, Saturn, Uranus, Neptune, Pluto or the Ort cloud. Their heads would explode. Try launching a probe like that knowing that you yourself may very well not live long enough to see it arrive and that children who are in 4th grade at launch date would likely be the scientists that would monitor and record the arrival. Do you have the patience for that?

Jeepers people. The solar system isn't your back yard that can be crossed in a leap and a bound.
SpaceX will provide photographs when it wants to and not one second before - they don't owe any of us a thing.
Falcon Heavy will launch when it is ready. - Give it a rest and have a cup of tea or coffee or latte-mocha-chi-whatever.
Chill. It will happen when it happens.
THIS site will be the first to let you know it's happening so just stay tuned and quit complaining.

Bah!
I DID wait through the 9.5 year journey to Pluto (Having worked on the mission)
One of my personal efforts has been in the works for twenty years, and it can't really yet be said to be a going concern.
But I want MORE PROGRESS.
I still remember the rapid progress of the "Space Race".
FASTER!
Fly that Heavy, already!

There.  I said it.  Now back to waiting.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 12/30/2017 10:07 PM


Yeah, judging from some coincidentally accurate porkchop plots and a few articles, Roadster can certainly make it to a rather close encounter with Mars, it just might take anywhere from a 12-24 month coast period to get there.

What's with the asymptote in that porkchop plot?  It seems like the required dV around Jan 15 is actually extremely sensitive to the exact date selected.  Is that just an artifact of some other choice made in the plot, or is there an actual orbital mechanics reason why Jan 15 would be so much worse than Jan 1?
I found the answer to my own question:
http://hopsblog-hop.blogspot.com/2013/01/deboning-porkchop-plot.html

So we're rapidly approaching the time period where an expensive 180 degree phase change is necessary to intercept Mars.  Unless SpaceX is willing to wait until late February, they are going to have to do a mid-course burn to do the necessary inclination change to intercept Mars.

This might have been a factor in SpaceX's desire to get the first FH launch off in December. Given that they don't seem like they're going to wait 50 days to launch it --- does that imply that the S2 can do a second inclination-change burn after a hundred days of loiter?  Or is there some other clever way to intercept Mars (a transfer that doesn't take 180 degrees of anomaly, for instance)?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mme on 12/30/2017 10:18 PM


Yeah, judging from some coincidentally accurate porkchop plots and a few articles, Roadster can certainly make it to a rather close encounter with Mars, it just might take anywhere from a 12-24 month coast period to get there.

What's with the asymptote in that porkchop plot?  It seems like the required dV around Jan 15 is actually extremely sensitive to the exact date selected.  Is that just an artifact of some other choice made in the plot, or is there an actual orbital mechanics reason why Jan 15 would be so much worse than Jan 1?
I found the answer to my own question:
http://hopsblog-hop.blogspot.com/2013/01/deboning-porkchop-plot.html

So we're rapidly approaching the time period where an expensive 180 degree phase change is necessary to intercept Mars.  Unless SpaceX is willing to wait until late February, they are going to have to do a mid-course burn to do the necessary inclination change to intercept Mars.

This might have been a factor in SpaceX's desire to get the first FH launch off in December. Given that they don't seem like they're going to wait 50 days to launch it --- does that imply that the S2 can do a second inclination-change burn after a hundred days of loiter?  Or is there some other clever way to intercept Mars (a transfer that doesn't take 180 degrees of anomaly, for instance)?
The Roadster is not going to Mars.  It’s going to orbit around the sun with its aphelion being about the same as Mars’ orbit.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rpapo on 12/30/2017 10:26 PM
So we're rapidly approaching the time period where an expensive 180 degree phase change is necessary to intercept Mars.
Weren't we told that this would be a launch to a Mars transfer orbit equivalent, not the real thing?  In such a case, all they are trying to do is launch to an orbit which will have as its apogee the orbit of Mars, and the perigee somewhere around the Earth.  In such a case, "porkchop" plots are meaningless.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Herb Schaltegger on 12/30/2017 10:54 PM

Bah!
I DID wait through the 9.5 year journey to Pluto (Having worked on the mission)
One of my personal efforts has been in the works for twenty years, and it can't really yet be said to be a going concern.
But I want MORE PROGRESS.
I still remember the rapid progress of the "Space Race".
FASTER!
Fly that Heavy, already!

There.  I said it.  Now back to waiting.

I can relate. Some of the hardware I spec'd and other stuff I actually designed as a baby engineer 27 years ago still gets mention in the L2 ISS Daily Status Reports thread every few weeks. Does my crusty old heart good, it does. Wish it'd all been replaced by a moonbase or mission to Mars by now but ...

Anyway, if this thing manages to launch next month without an Earth-shattering kaboom, I'll be that much closer to someone, ANYONE, sending people to Mars than I've ever personally been in my lifetime. :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/31/2017 12:18 AM
So FH spent less than a day at the pad doing fit checks.
Fit checks are short. No obvious issue present. If they were to repeat the rollout, then there may have been an issue. Looks fine.

I think the probability of success is pretty high, but not as high as a F9 of course.
I think 50-50 is about right.  That's what Elon suggested, if I recall correctly.
Your usual measure of success as the qualifier of the "50=50"?

Quote
The first Delta 4 Heavy failed...
Successful launch. Mission failure due to under performance (booster, US couldn't make up within margins).

It made it to a lower orbit due to a performance shortfall (main engine early shutdown was triggered by an empty tank signal from the fuel sensor during the first stage due to cavitation around the propellant feed). Unforeseen issue.

...

Thanks for explanation, but I'm still stumped by the 1 vs 3 core?

Whatever torque issues are on one core they have obviously solved, so what happens when you have 3 cores side by side? as I said in my question: why is it a larger problem and not the same problem 3 times (with the same solution applied 3 times)?
If you watch the the liftoff of the first Falcon 9, it clearly rotates.  For a single stick, that's not really a big deal.  But now bolt three of them together and rather than rotate freely in space they will be torquing the connections.

https://www.youtube.com/watch?v=H6hYEqrP56I

The issue they are worried about is during ignition, not during flight.

(and we've seen many launches since then, I don't think they have a problem here)
The issue is the vehicle ensemble, not ignition.

Static fire includes assessing vehicle performance briefly while still on the launch mount.  It won't be released if anomalous on launch.

The gimbal of the engines is fully capable of eliminating or inducing any roll wanted or unwanted.
For each core. The concern is the ensemble acting unpredictably.

After release, your concern is clearing the pad/TE/tower/facility. Sufficient performance and control.

I'm not concerned by any flight control guidance authority issues, just potential pneumatics and unlatch hangs at  booster sep...
That's late in flight. Before that you'll have structural issues to contend with, as well as guidance.

Vehicle stability pre/post sep is as important as sep event itself.

Due to thrust torque (a thrust-induced rotation)...

I believe the torque mentioned is around a horizontal axis. A single stick might use an asymmetric engine ignition sequence without overstressing its own octaweb. But placed side by side, the asymmetric startup thrusts could overstress one or both webs. Now think of that happening on both sides of the center booster web simultaneously... complex.

I thought the problem would actually be in any mismatch in the overall thrust startup of the two side boosters, which could result (say) in the links on one side of the center booster being lift-loaded before the other. Could cause a center tube or link failure, I would imagine. Fireball.
Three axial, elastic cylinders each with roll/pitch/yaw and coupling. Also TO which is unpredictable with resonance in the ensemble.

Much of this has been well simulated so unlikely a fireball. More likely is stability/performance issues where the vehicle does not perform adequately, possibly to the point of RSO/AFTS termination, if the GNC can't handle it.

add:
Almost forgot - DIVH first flew 12/21/2004, so also at the turn of the year 13 years ago.


Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: LouScheffer on 12/31/2017 12:58 AM
If they truly think that FH only has a 50% chance of succeeding, they are not going to launch. Period. They are going to want to be a lot more confident than that.

I don't agree.  I'm not sure it's possible to get more than 50% confident.

Of course, SpaceX will have addressed 100% of the problems that they have thought of.   But so has every other rocket maker, and historically about 50% of the first try of a new rocket have failed (see Rocketlab for the most recent example...).

So Musk might well believe, that after addressing every problem they know about, there is still a 50% chance of failure.  And there is nothing they can do about this, since they have already addressed every problem they could imagine.   The only way to proceed is to launch and let nature have a go at seeing what SpaceX could not.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 12/31/2017 03:02 AM
If they truly think that FH only has a 50% chance of succeeding, they are not going to launch. Period. They are going to want to be a lot more confident than that.

I don't agree.  I'm not sure it's possible to get more than 50% confident.

Of course, SpaceX will have addressed 100% of the problems that they have thought of.   But so has every other rocket maker, and historically about 50% of the first try of a new rocket have failed (see Rocketlab for the most recent example...).

So Musk might well believe, that after addressing every problem they know about, there is still a 50% chance of failure.  And there is nothing they can do about this, since they have already addressed every problem they could imagine.   The only way to proceed is to launch and let nature have a go at seeing what SpaceX could not.
Yup. Musk hasn't forgotten F1, or the two F9 failures.  I don't know how he got through 18 launches this year w/o a heart attack.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: dorkmo on 12/31/2017 04:39 AM
Larger versions
In the post (on the update thread) I'm referencing, the posted image of the 27-Merlin business end (FH-mated3.jpg) has four curious objects, a pair between each side booster and the main.  A colleague on another forum speculated that they might be damping devices, and I speculate they might be actuators in the separation system.  I've cropped a closeup from the cited photo and am attaching it as FH_Whazzat_0.jpg. 

Does anyone know what they are, or care to guess?

id guess the left side is the release mechanism. The right cylinder might be a dampener.

interesting white dots. Might be used to record video of dampener movement?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: wannamoonbase on 12/31/2017 04:42 AM
I see very little (if any) risk for POGO for FH, since they are flying the same stages as F9. Same engines, same tank lengths. POGO - if present - will show up in early launches.

All this talk of possible failure points - one more dramatic than the next - starts to border on concern trolling, IMO. “Surely SpaceX has not thought of *this*?”

Agreed, lots of smart people, with hands on experience doing very hard things have done tons of work on this.

I think it will work fine, but if something gets it, it’s not likely something like structural analysis not being thorough enough.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisC on 12/31/2017 04:51 AM
I love Elon's remark (about a year ago) that if Falcon Heavy just lifts off and clears the LC-39A launchpad, he'll consider the test a success.  Certainly it would be a Bad Day for all involved to lose LC-39A.

Has anyone done the math for at what point during flight, if the whole stack breaks up, will the ballistics carry the debris back down to earth CLEAR of the launch complex?  (i.e. NOT do what Antares did to Wallops Pad 0 in Oct 2014)  Obviously this moment would be after the pitchover starts.

The simplest calc would be to just treat the whole stack as a point mass and then run that back down to ground -- i.e. just watch the instantaneous impact point (IIP) and wait for it to clear the fenceline, plus whatever distance is appropriate for the impact fireball.  The harder calc would be assuming that the stack detonates, and now you've got a debris cloud that's raining down, including some that was propelled BACK to the west.  So how much further would it need to be out for the propelled debris to also clear?

My guess is it's around 30 seconds, give or take 10 seconds.  That's the moment on the mission clock that I'll be watching for ...

Sorry to be macabre.  It's what engineers do, anticipate everything that can go wrong, right?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 12/31/2017 05:53 AM
I love Elon's remark (about a year ago) that if Falcon Heavy just lifts off and clears the LC-39A launchpad, he'll consider the test a success.  Certainly it would be a Bad Day for all involved to lose LC-39A.

Has anyone done the math for at what point during flight, if the whole stack breaks up, will the ballistics carry the debris back down to earth CLEAR of the launch complex?  (i.e. NOT do what Antares did to Wallops Pad 0 in Oct 2014)  Obviously this moment would be after the pitchover starts.

The simplest calc would be to just treat the whole stack as a point mass and then run that back down to ground -- i.e. just watch the instantaneous impact point (IIP) and wait for it to clear the fenceline, plus whatever distance is appropriate for the impact fireball.  The harder calc would be assuming that the stack detonates, and now you've got a debris cloud that's raining down, including some that was propelled BACK to the west.  So how much further would it need to be out for the propelled debris to also clear?

My guess is it's around 30 seconds, give or take 10 seconds.  That's the moment on the mission clock that I'll be watching for ...

Sorry to be macabre.  It's what engineers do, anticipate everything that can go wrong, right?
I think the main damage is the unburned fuel.

The kinetics of the rocket structure coming back down can't be that destructive.

Going back to that Delta II, the pieces of the solids were I think mostly acting as incindiaries.

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: kevinof on 12/31/2017 07:31 AM
Not sure about the timing but I'll be holding my breath until it clears away from the pad. Would hate to damage/destroy all that. For me that's about 10/15 seconds and anything after that should be over the ocean.

...
My guess is it's around 30 seconds, give or take 10 seconds.  That's the moment on the mission clock that I'll be watching for ...

Sorry to be macabre.  It's what engineers do, anticipate everything that can go wrong, right?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: john smith 19 on 12/31/2017 07:34 AM

I don't agree.  I'm not sure it's possible to get more than 50% confident.

Of course, SpaceX will have addressed 100% of the problems that they have thought of.   But so has every other rocket maker, and historically about 50% of the first try of a new rocket have failed (see Rocketlab for the most recent example...).

So Musk might well believe, that after addressing every problem they know about, there is still a 50% chance of failure.  And there is nothing they can do about this, since they have already addressed every problem they could imagine.   The only way to proceed is to launch and let nature have a go at seeing what SpaceX could not.
Bayesian statistics also look at the history of successful (or unsuccessful) "trials."

Obviously FH <> F9 but the question is how much different is it? The F9 has had a pretty successful year and the launch crew has had plenty of practice. The boosters are flight proven so the big unknowns are the core and the interactions between the cores and the whole assembly with the launch pad during launch.

I'd suggest that puts confidence > 50%. How  much above 50% is of course debatable.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: TorenAltair on 12/31/2017 10:57 AM
Not sure about the timing but I'll be holding my breath until it clears away from the pad. Would hate to damage/destroy all that. For me that's about 10/15 seconds and anything after that should be over the ocean.

...
My guess is it's around 30 seconds, give or take 10 seconds.  That's the moment on the mission clock that I'll be watching for ...

Sorry to be macabre.  It's what engineers do, anticipate everything that can go wrong, right?

And I thought I'm the only one who will hold my breath until 50-60 Seconds (and therefore H=10km) will have been passed.
Mission target 1 in my eyes: Don't destroy anything except the rocket.
Target 2: get to side-core-sep
Target 3: get rid of the central core
Then I would rate it as a 99% success. Landing (esp. 2 cores in parallel would be nice to watch of course) and stage 2 are just bonuses in my eyes.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Oersted on 12/31/2017 02:44 PM
If you look at this fabulous Falcon Heavy launch simulation vid by Zach and freeze it at the right time you should get an idea of when the stack wouldn't tumble back on the launch pad:

https://www.youtube.com/watch?v=lDvzUG92wGY

Looks like around 15 seconds elapsed mission time to me.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: kevinof on 12/31/2017 03:58 PM
If you look at this fabulous Falcon Heavy launch simulation vid by Zach and freeze it at the right time you should get an idea of when the stack wouldn't tumble back on the launch pad:

https://www.youtube.com/watch?v=lDvzUG92wGY

Looks like around 15 seconds elapsed mission time to me.
I saw that. At 15 secs it's 500m altitude but still right above the pad. Think I might stretch that 15 secs to 30.

Sent from my SM-J510FN using Tapatalk

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/31/2017 04:08 PM
I think we can stop worrying when it clears land, not just the pad complex.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisC on 12/31/2017 04:12 PM
My guess is it's around 30 seconds, give or take 10 seconds.  That's the moment on the mission clock that I'll be watching for ...

If you look at this fabulous Falcon Heavy launch simulation vid by Zach and freeze it at the right time you should get an idea of when the stack wouldn't tumble back on the launch pad ... Looks like around 15 seconds elapsed mission time to me.

Thanks Oersted for the link to that GREAT simulation.

Zach (was that ZachS09?), could you run that with a view from the side, showing the IIP during the first 30 seconds?  (in other words, keep the ground in view, and we can use the stack height to estimate horizontal distance.

Per the simulation, the pitchover doesn't even start until +15 seconds, so +15 secs is definitely NOT long enough (it will fall straight back down, a la Antares as I mentioned).  By my guess, looking at downrange distance, altitude and apogee, it's not until about +25 seconds (+/- 5 secs) that the IIP would clear the LC-39A fenceline, 400 meters from the pad.  We are converging on a solution :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 12/31/2017 04:30 PM
My guess is it's around 30 seconds, give or take 10 seconds.  That's the moment on the mission clock that I'll be watching for ...

If you look at this fabulous Falcon Heavy launch simulation vid by Zach and freeze it at the right time you should get an idea of when the stack wouldn't tumble back on the launch pad ... Looks like around 15 seconds elapsed mission time to me.

Thanks Oersted for the link to that GREAT simulation.

Zach, could you run that with a view from the side, showing the IIP during the first 30 seconds?  (in other words, keep the ground in view, and we can use the stack height to estimate horizontal distance.

Per the simulation, the pitchover doesn't even start until +15 seconds, so +15 secs is definitely NOT long enough (it will fall straight back down, a la Antares as I mentioned).  By my guess, looking at downrange distance, altitude and apogee, it's not until about +25 seconds (+/- 5 secs) that the IIP would clear the LC-39A fenceline, 400 meters from the pad.  We are converging on a solution :)
Antares didn't activate the flight termination system, so it came down as two full tanks.

(I never saw an explanation why, btw)

Hopefully SpaceX will be faster on the trigger if it happens.

Propellant dispersal is really important in these situations.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 12/31/2017 04:37 PM
My guess is it's around 30 seconds, give or take 10 seconds.  That's the moment on the mission clock that I'll be watching for ...

If you look at this fabulous Falcon Heavy launch simulation vid by Zach and freeze it at the right time you should get an idea of when the stack wouldn't tumble back on the launch pad ... Looks like around 15 seconds elapsed mission time to me.

Thanks Oersted for the link to that GREAT simulation.

Zach, could you run that with a view from the side, showing the IIP during the first 30 seconds?  (in other words, keep the ground in view, and we can use the stack height to estimate horizontal distance.

Per the simulation, the pitchover doesn't even start until +15 seconds, so +15 secs is definitely NOT long enough (it will fall straight back down, a la Antares as I mentioned).  By my guess, looking at downrange distance, altitude and apogee, it's not until about +25 seconds (+/- 5 secs) that the IIP would clear the LC-39A fenceline, 400 meters from the pad.  We are converging on a solution :)
Antares didnt activate the flight termination system, so it came down as two full tanks.

Hopefully SpaceX will be faster on the trigger if it happens.

Propellant dispersal is really important in these situations.

Every gallon of propellant burned in the air is a gallon of propellant not burning the pad up.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/31/2017 04:51 PM
It's 975m from the pad due east to the ocean. Assuming that if the vehicle fails it travels ballistically from that point onwards the sim suggests that any time after 30 seconds the pad is safe. After 40 seconds or so the remains would land in the water and after a minute the vehicle is flying over the sea.

Sources: the above linked sim and the ruler buried in the left click menu of google maps.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 12/31/2017 04:57 PM
If you look at this fabulous Falcon Heavy launch simulation vid by Zach and freeze it at the right time you should get an idea of when the stack wouldn't tumble back on the launch pad:

https://www.youtube.com/watch?v=lDvzUG92wGY

Looks like around 15 seconds elapsed mission time to me.
Watch the bouncing IIP as it suddenly has a horizontal component. I'd say a half minute.

(Zach's video does a fine job. If I were to add anything it would be corrected sways/bends in combined flight, then minor twists during booster sep. Great work!)

One might fire it up on actual FH launch in side by side - then you'll notice the little differences more easily in the actual.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Greg Hullender on 12/31/2017 04:59 PM
I thought the center core was only going to fire until shortly after liftoff and then reignite when the side boosters separated. Has that changed?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jak Kennedy on 12/31/2017 05:05 PM
I seem to recall some rockets start moving actively move away from directly above the pad as soon as they clear the tower. ie sliding in a horizontal direction for a few seconds so that any debris would clear the pad.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mme on 12/31/2017 05:16 PM
The center core will throttle downn but it will not shutdown its engines.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 12/31/2017 05:46 PM
My guess is it's around 30 seconds, give or take 10 seconds.  That's the moment on the mission clock that I'll be watching for ...

If you look at this fabulous Falcon Heavy launch simulation vid by Zach and freeze it at the right time you should get an idea of when the stack wouldn't tumble back on the launch pad ... Looks like around 15 seconds elapsed mission time to me.

Thanks Oersted for the link to that GREAT simulation.

Zach (was that ZachS09?), could you run that with a view from the side, showing the IIP during the first 30 seconds?  (in other words, keep the ground in view, and we can use the stack height to estimate horizontal distance.

Per the simulation, the pitchover doesn't even start until +15 seconds, so +15 secs is definitely NOT long enough (it will fall straight back down, a la Antares as I mentioned).  By my guess, looking at downrange distance, altitude and apogee, it's not until about +25 seconds (+/- 5 secs) that the IIP would clear the LC-39A fenceline, 400 meters from the pad.  We are converging on a solution :)

It was a different Zach that ran that simulation. I had nothing to do with it.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Oersted on 12/31/2017 05:59 PM
Watch the bouncing IIP as it suddenly has a horizontal component. I'd say a half minute.

Yup, true, 15 seconds is a bit too early. At half a minute into the flight the projected path has moved quite a bit away from the launch complex, in my estimation. Still a bit too early for comfort, though!

Here is a screenie of the dots you need to keep an eye on...

(Please note that the lift-off is 20 seconds in from the beginning of the movie. This screenie is consequently 11 seconds into the flight, where - if the engines were to stop immediately - the rocket would just rise by a bit more than its own length before it would fall back down.)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 12/31/2017 06:07 PM
It's easier just to keep a note of the downrange distance displayed in the top left of the sim.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: speedevil on 12/31/2017 07:01 PM
It's easier just to keep a note of the downrange distance displayed in the top left of the sim.

(altitude/downrange) gives a rough estimate of the current launch angle from vertical.
perigee*2/(altitude/downrange) is a conservative estimate of how far it will travel horizontally.

At 100m altitude, it's gone 20m, apogee is 87m.

200 24 233 55
400 24 540 64
1000 36 1562 112
1500 54 2300 165
2500 124 4200 416
3500 200 6000 685
5000 350 8400 1176

So, ~5km, ~40s in means the IIP is likely to be on water.

But, I don't believe this at all for a few reasons. Unless the stage just stops thrusting, and falls intact, it's really, really not going to be ballistic.
Once apogee hits ~1km or so, 12s in, if the FTS triggers, you're getting shards, not any part of the rocket.
So, hold your breath, and when you let it out it's fine.
If it explodes, once you're over a few hundred meters, most of the cloud of debris is going to be shards of sooty fuel tank, with the COPVs and engines falling intact.
Very small tweaks to the trajectory that are essentially free variables and have no impact on launch performance can change the impact dramatically.

Still, a minute in is certainly pad safe,
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: wannamoonbase on 12/31/2017 09:26 PM
If it makes it past the first few seconds it’s likely fine till staging. 

Then, hey, who knows, if it survives staging the side boosters I think it will be completely successful.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: zlynn1990 on 12/31/2017 10:29 PM
Oersted I'm the Zach who made the sim :) Most of that trajectory was done by OneSpeed, and he has the gravity turn starting at 10 seconds. Take the entire thing was a large grain of salt because there are a lot of unknowns right now.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Surfdaddy on 12/31/2017 11:11 PM
If it makes it past the first few seconds it’s likely fine till staging. 

Then, hey, who knows, if it survives staging the side boosters I think it will be completely successful.

I want to believe you, but I've seen a lot of launch videos where problems happen in your "safe" time period.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Oersted on 12/31/2017 11:27 PM
Oersted I'm the Zach who made the sim :) Most of that trajectory was done by OneSpeed, and he has the gravity turn starting at 10 seconds. Take the entire thing was a large grain of salt because there are a lot of unknowns right now.

Yes, I realise it is a good guess more than anything else. Nevertheless, splendid effort. Thanks so much for putting the vid together. It is clear that a lot of love went into it. Kudos and happy new year!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 01/01/2018 12:56 AM
My guess is it's around 30 seconds, give or take 10 seconds.  That's the moment on the mission clock that I'll be watching for ...

If you look at this fabulous Falcon Heavy launch simulation vid by Zach and freeze it at the right time you should get an idea of when the stack wouldn't tumble back on the launch pad ... Looks like around 15 seconds elapsed mission time to me.

Thanks Oersted for the link to that GREAT simulation.

Zach (was that ZachS09?), could you run that with a view from the side, showing the IIP during the first 30 seconds?  (in other words, keep the ground in view, and we can use the stack height to estimate horizontal distance.

Per the simulation, the pitchover doesn't even start until +15 seconds, so +15 secs is definitely NOT long enough (it will fall straight back down, a la Antares as I mentioned).  By my guess, looking at downrange distance, altitude and apogee, it's not until about +25 seconds (+/- 5 secs) that the IIP would clear the LC-39A fenceline, 400 meters from the pad.  We are converging on a solution :)

Usually the IIP is the thing to watch, but this assumes the rocket continues as an inert solid body - as if the engines are shut off and nothing else breaks.

In an early failure scenario, two things will likely happen - off-axis thrust will move the IIP very quickly in some random directions, and then FTS will make the whole thing "stop cold" and fall straight down, but influenced by wind.

At some altitude, the liquid fuel will have time to burn on the way down, or disperse enough that it doesn't pool on the ground, and that will already be a "safe" situation.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: joek on 01/01/2018 02:44 AM
Usually the IIP is the thing to watch, but this assumes the rocket continues as an inert solid body - as if the engines are shut off and nothing else breaks.

IIP is a point spread function based on numerous parameters.  You can only state "probability of IIP at point X,Y is Z based on parameters T, P, Q, R, ...".  Constrain the parameters sufficiently and you can assert that it "continues as an inert solid body".  However, most real-world models (probabilistic-time-based) do not apply such constraints or make such assumptions--unless the parameters are well bounded and understood  (e.g., close to lift off).  Which is why the models tend to vary their parameters over the flight path (in particular, probability vs. time, as spread-uncertainty tends to increase with time).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 01/01/2018 05:16 AM
Usually the IIP is the thing to watch, but this assumes the rocket continues as an inert solid body - as if the engines are shut off and nothing else breaks.

IIP is a point spread function based on numerous parameters.  You can only state "probability of IIP at point X,Y is Z based on parameters T, P, Q, R, ...".  Constrain the parameters sufficiently and you can assert that it "continues as an inert solid body".  However, most real-world models (probabilistic-time-based) do not apply such constraints or make such assumptions--unless the parameters are well bounded and understood  (e.g., close to lift off).  Which is why the models tend to vary their parameters over the flight path (in particular, probability vs. time, as spread-uncertainty tends to increase with time).
I forget where I saw a realtime IIP displayed, but I got the impression it was simply ballistic.

You're correct that a true IIP estimate is a stochastic thing.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gadgetmind on 01/01/2018 09:47 AM
I wonder how FH would handle an engine failure on a side booster? I guess it would need to throttle down the other side? Throw in scenarios of failures of two engines in various configurations and it could all get complicated.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: SLC on 01/01/2018 01:57 PM
I wonder how FH would handle an engine failure on a side booster? I guess it would need to throttle down the other side? Throw in scenarios of failures of two engines in various configurations and it could all get complicated.
Would it be too off-topic to give this link to the last time a rocket with this many engines made its (short) first flight -  the Soviet N1 moon rocket 49 years ago next month:

http://www.russianspaceweb.com/n1_3l.html

On that occasion the KORD control system did indeed diagnose an engine failure on one side, it did shut down the symmetrically opposite engine to compensate, and then it all got complicated ...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: speedevil on 01/01/2018 02:11 PM
I wonder how FH would handle an engine failure on a side booster? I guess it would need to throttle down the other side? Throw in scenarios of failures of two engines in various configurations and it could all get complicated.

Maybe.
From memory, it has been said that the first launch will be at 82% thrust.
This is considerably more than 9/8ths, so you can lose certain engines, and simply throttle up on others with no external changes in thrust vector.
For example, lose an inboard engine on a booster, and if you throttle the remaining outboard ones to 92%, the centre of thrust moves out from the core by perhaps half an engine diameter.

If you throttle the outer engine to nearly minimum, the ones next to the core to ~105%, then it may not move at all.

Only once you can no longer keep a booster or cores thrust vector within narrow limits would you need to make changes to the thrust profile of the stack as a whole.

Would it be too off-topic to give this link to the last time a rocket with this many engines made its (short) first flight -  the Soviet N1 moon rocket 49 years ago next month:
Yes.

More seriously, N1 failures are not comparable in so many ways, as overall QC and management was so terrible that it loses all meaning as a reasonable comparator.

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: the_other_Doug on 01/01/2018 02:33 PM
From memory, it has been said that the first launch will be at 82% thrust.

And from actuality (not your memory), it will fly at 92% thrust.  Not 82%.  And not just "has been said," but tweeted by Elon Musk.

It's refreshing to see other people have even worse memories than I do... :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: speedevil on 01/01/2018 03:12 PM
From memory, it has been said that the first launch will be at 82% thrust.

And from actuality (not your memory), it will fly at 92% thrust.  Not 82%.  And not just "has been said," but tweeted by Elon Musk.

It's refreshing to see other people have even worse memories than I do... :)

Thanks. This would put required thrust for other engines at ~103% on a core, and remove capability for playing with the thrust levels to bring the centre of thrust to the same place.
One engine out on any or even all cores is probably quite managable.
More than one a core especially early in flight might lead to problems.
 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Semmel on 01/01/2018 04:32 PM
If the engine failure at the side booster happens before the throttle back of the center core, the situation may become hairy as the thrust difference between center and side boosters might not work with the structure of the heavy assembly. Maybe the center would have to throttle back prematurely.
The thrust to weight at launch should be around 1.5. With 11% thrust missing it should still be launching without much problems.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 01/01/2018 05:08 PM
If the engine failure at the side booster happens before the throttle back of the center core, the situation may become hairy as the thrust difference between center and side boosters might not work with the structure of the heavy assembly. Maybe the center would have to throttle back prematurely.
The thrust to weight at launch should be around 1.5. With 11% thrust missing it should still be launching without much problems.

One engine is 3.7%
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Gotorah on 01/01/2018 05:30 PM
This is not comparing Falcon Heavy 1 vs Falcon Heavy 2. It is comparing right side vs left side for balanced thrust. If one is lost on one side, those remaining on that side can be throttled up a few percent and if needed the ones on the opposite booster can be throttled down a few.  I bet a dollar to a doughnut that the SpaceX Flight Software engineers have it all programmed. All we have to do is watch in awe !
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Semmel on 01/01/2018 05:50 PM
If the engine failure at the side booster happens before the throttle back of the center core, the situation may become hairy as the thrust difference between center and side boosters might not work with the structure of the heavy assembly. Maybe the center would have to throttle back prematurely.
The thrust to weight at launch should be around 1.5. With 11% thrust missing it should still be launching without much problems.

One engine is 3.7%

If center and opposite core need to match the loss of thrust, it's 11.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 01/01/2018 07:22 PM
If the engine failure at the side booster happens before the throttle back of the center core, the situation may become hairy as the thrust difference between center and side boosters might not work with the structure of the heavy assembly. Maybe the center would have to throttle back prematurely.
The thrust to weight at launch should be around 1.5. With 11% thrust missing it should still be launching without much problems.

One engine is 3.7%

If center and opposite core need to match the loss of thrust, it's 11.

Since running at 92%, the remaining engines in a core can throttle up to compensate - at any point in the flight.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 01/01/2018 08:34 PM
I think this is an interesting conversation. However I believe it would be better suited to be on the general Falcon Heavy discussion thread rather than on this mission specific thread?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Nomadd on 01/01/2018 09:25 PM
I think this is an interesting conversation. However I believe it would be better suited to be on the general Falcon Heavy discussion thread rather than on this mission specific thread?
The 92% thrust level might only be for this mission.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 01/01/2018 09:33 PM
The 92% thrust level might only be for this mission.

I've wondered if the thrust "reduction" on this mission is just because he's giving thrust numbers for FH Block 5 and this vehicle is running at Block 3 levels.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 01/01/2018 09:47 PM
The 92% thrust level might only be for this mission.

I've wondered if the thrust "reduction" on this mission is just because he's giving thrust numbers for FH Block 5 and this vehicle is running at Block 3 levels.

Maybe this Falcon Heavy is running at 92% of the Block 3 thrust level, which is about 4.14 million pounds as opposed to 4.5 million pounds.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 01/01/2018 11:57 PM
The 92% thrust level might only be for this mission.

I've wondered if the thrust "reduction" on this mission is just because he's giving thrust numbers for FH Block 5 and this vehicle is running at Block 3 levels.

Here's the tweet that was threaded with the photos. Agree the older side cores wouldn't be capable of taking this flight to 100% of 5.1

https://twitter.com/elonmusk/status/943590152181448704
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: butters on 01/02/2018 12:22 AM
It's safe to say that this will be only Falcon Heavy ever to use pre-Block 5 cores. After re-scoping Falcon Heavy to chase F9 iterations to v1.1 and then to FT specifications, now there's Block 5 coming. SpaceX needed to make the decision whether to bring the FH demo vehicle up to Block 5 spec with bolted octowebs etc. and accept further delays to a program already repeatedly delayed by F9 iteration churn -- or to simply launch the damn thing already even though it will end up being a one-off. This will forever be the unique "albino" FH demo vehicle.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jpo234 on 01/02/2018 12:55 AM
It's safe to say that this will be only Falcon Heavy ever to use pre-Block 5 cores. After re-scoping Falcon Heavy to chase F9 iterations to v1.1 and then to FT specifications, now there's Block 5 coming. SpaceX needed to make the decision whether to bring the FH demo vehicle up to Block 5 spec with bolted octowebs etc. and accept further delays to a program already repeatedly delayed by F9 iteration churn -- or to simply launch the damn thing already even though it will end up being a one-off. This will forever be the unique "albino" FH demo vehicle.
As mentioned in the STP - 2 thread, there might only be one other FH. Reason: B5 cores should have more flights in them than there are FH missions on the manifest.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: allio on 01/02/2018 01:24 AM
First time poster.

Regarding the 92% thrust.

Is this not simply because it's an LV capable of lifting 16000kg to MTO that is in fact only lifting off with a 1500kg payload. An LV that can hoist 60000kg off the pad only lifting 1500kg (or whatever the weight of the tesla + mounting is) would go into a massive over g situation within seconds lifting that light a load. As it is I would imagine the 92% will only be until it clears the pad, then a massive throttle down until well past max q and throttling down all the way up. A lot of rockets auto throttle to constant 5g acceleration for structural reasons IIRC. This baby in its maiden config will have plenty of horses to spare.

Or am I wrong on that?

Edit: Does anyone know if there is extra ballast in the payload to counteract this? Or what the actual final payload weight actually will be?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 01/02/2018 02:42 AM
First time poster.

Regarding the 92% thrust.

Is this not simply because it's an LV capable of lifting 16000kg to MTO that is in fact only lifting off with a 1500kg payload. An LV that can hoist 60000kg off the pad only lifting 1500kg (or whatever the weight of the tesla + mounting is) would go into a massive over g situation within seconds lifting that light a load. As it is I would imagine the 92% will only be until it clears the pad, then a massive throttle down until well past max q and throttling down all the way up. A lot of rockets auto throttle to constant 5g acceleration for structural reasons IIRC. This baby in its maiden config will have plenty of horses to spare.

Or am I wrong on that?

Edit: Does anyone know if there is extra ballast in the payload to counteract this? Or what the actual final payload weight actually will be?

Not exactly
Most of the mass being carried by by the first stage, or the core in the case of Heavy, is the fueled second stage. Others can give you the numbers, but in general having a very light payload  doesn’t change things dramatically until well into the second stage burn.
Looked at it another way, running at 92% thrust cuts it by about a half million pounds. The payload is not 100,000 pounds less than the advertised maximum. Even at the max acceleration before staging it’s a smaller effect than the throttling. 
(Sorry for the archaic units. Trying to use one for all and I know the thrust in pounds.)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 01/02/2018 03:18 AM
Here's a reminder of the thrust profile, tweeted way back in July. Took a minute to find again but I knew I'd seen it somewhere

https://twitter.com/elonmusk/status/890810308326940672
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: allio on 01/02/2018 03:31 AM
there is abou 135000 lbs difference between max payload and that tesla :)

I may have overstated the throttling earlier :) but maybe not, as a quick read indicates that the fully loaded shuttles would be running at 65% thrust by max q, with the SRB's deigned to derate their thrust to 66% through propellant design after 50 seconds as well. And that's for a full load.

I believe the shuttle and falcon max q points are similar(13-14km).

at max q i'd expect the boosters in the FH configuration to have burned over half their fuel, with the core down by a third of it's fuel, at which point that 135k lbs in the nose becomes a much greater ratio of the remaining weight of the craft, which in turn adversely affects TWR forcing more throttling etc.

I thought throttling was used to maintain a specific TWR so as not to accelerate too early in the flight where the atmosphere is thicker where overspeed can lead to instability, extra structural loading and heating from excess aerodynamic resistance etc.

I would imagine that the core booster will throttle down earlier to offset the light payload.

anyway. just my basic understanding of rocketry

cyndy- That tweet references how the rocket thrust profile will work in general, not how the individual mission thrust profile will be deployed.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Stan-1967 on 01/02/2018 05:11 AM
there is abou 135000 lbs difference between max payload and that tesla :)

I believe the shuttle and falcon max q points are similar(13-14km).

at max q i'd expect the boosters in the FH configuration to have burned over half their fuel, with the core down by a third of it's fuel, at which point that 135k lbs in the nose becomes a much greater ratio of the remaining weight of the craft, which in turn adversely affects TWR forcing more throttling etc.

I thought throttling was used to maintain a specific TWR so as not to accelerate too early in the flight where the atmosphere is thicker where overspeed can lead to instability, extra structural loading and heating from excess aerodynamic resistance etc.

I would imagine that the core booster will throttle down earlier to offset the light payload.

anyway. just my basic understanding of rocketry


I think you have the right concept about how throttling is used to manage Max-Q, heating, & loading, however you are in error regarding the importance you assign to the weight of the Tesla in comparison to the largest theoretical payload FH can carry when you focus on the 135k lbs difference. 

Keep in mind there is no payload on the FH manifest that exceeds 8t ( 17.6k lbs ).  The largest payload that Delta V Heavy can lift to GTO is around 14.2t ( 31.4k lbs), & FH hopes to enter the market for this payload class.  That is the ballpark maximum foreseeable payload for FH.    Also understand that the existing F9 or FH PAF can only accomodate up to 24k lbs.   The max payload of FH may never be used.

The thrust profile for the Tesla will not be radically different than what will be used for FH GTO launches.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: hkultala on 01/02/2018 06:06 AM
there is abou 135000 lbs difference between max payload and that tesla :)

No, there is not.

The 63 tonne number in spacex web site is for LEO (total delta-v about 9km/s), and even that number is notional as there actually currently is no a payload adapter capable of holding that mass.

The roadster will go to non-optimal trajectory that goes near Mars(over 13km/s needed).
On optimal trajectory, FH payload to Mars is about 17 tonnes.







I may have overstated the throttling earlier :) but maybe not, as a quick read indicates that the fully loaded shuttles would be running at 65% thrust by max q, with the SRB's deigned to derate their thrust to 66% through propellant design after 50 seconds as well. And that's for a full load.

I believe the shuttle and falcon max q points are similar(13-14km).
[/quote]

FH should initially accelerate much faster than STS, as it has considerable higher T/W ratio at liftoff.

On the other hand, to make booster RTLS use less delta-v, FH will have higher trajectory than STS, making it also rise from the dense air to the thinner air earlier.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Tonioroffo on 01/02/2018 06:53 AM
I see a lot did posts concerning "when can it explode to not damage towers/endanger infra" but what about the aftermath?  If we do get late New Year fireworks, are we automatically looking at (long) stand down for the entire F9 family?  I would think months of delays for Crew effort?  Or am I wrong?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: MattMason on 01/02/2018 07:18 AM
I see a lot did posts concerning "when can it explode to not damage towers/endanger infra" but what about the aftermath?  If we do get late New Year fireworks, are we automatically looking at (long) stand down for the entire F9 family?  I would think months of delays for Crew effort?  Or am I wrong?

Even with my limited understanding of launch mechanics, I know that an FH failure won't sideline any F9 flights. The worst case (explosion on pad; <1% chance) means that Commercial Crew flights may be delayed since they must use LC39A. The F9 is its own tried and true vehicle. FH is a new vehicle--thus, the test flight to rack up flight data.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CJ on 01/02/2018 08:06 AM
I see a lot did posts concerning "when can it explode to not damage towers/endanger infra" but what about the aftermath?  If we do get late New Year fireworks, are we automatically looking at (long) stand down for the entire F9 family?  I would think months of delays for Crew effort?  Or am I wrong?

Even with my limited understanding of launch mechanics, I know that an FH failure won't sideline any F9 flights. The worst case (explosion on pad; <1% chance) means that Commercial Crew flights may be delayed since they must use LC39A. The F9 is its own tried and true vehicle. FH is a new vehicle--thus, the test flight to rack up flight data.

That's not necessarily true. There's a lot of commonality between FH and F9, so depending on what the failure is, it might cause an F9 stand down, in the same way that the F9R destruct at McGreggor caused an F9 stand down until they were sure the cause wasn't something that would affect a flight F9. 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gadgetmind on 01/02/2018 08:31 AM
On that occasion the KORD control system did indeed diagnose an engine failure on one side, it did shut down the symmetrically opposite engine to compensate, and then it all got complicated ...

Thanks for the link. Interesting that they kept changing the control system to *not* shut down engines willy nilly even when things went very bad as they didn't want to destroy the pad. OK, they still destroyed the pad, but it was a good plan despite this.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ictogan on 01/02/2018 10:12 AM
I see a lot did posts concerning "when can it explode to not damage towers/endanger infra" but what about the aftermath?  If we do get late New Year fireworks, are we automatically looking at (long) stand down for the entire F9 family?  I would think months of delays for Crew effort?  Or am I wrong?

Even with my limited understanding of launch mechanics, I know that an FH failure won't sideline any F9 flights. The worst case (explosion on pad; <1% chance) means that Commercial Crew flights may be delayed since they must use LC39A. The F9 is its own tried and true vehicle. FH is a new vehicle--thus, the test flight to rack up flight data.
And what makes you so certain there's <1% chance of an explosion on the pad? Would you have said the same about F9 prior to AMOS-6?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: sevenperforce on 01/02/2018 12:11 PM
I see a lot did posts concerning "when can it explode to not damage towers/endanger infra" but what about the aftermath?  If we do get late New Year fireworks, are we automatically looking at (long) stand down for the entire F9 family?  I would think months of delays for Crew effort?  Or am I wrong?

Even with my limited understanding of launch mechanics, I know that an FH failure won't sideline any F9 flights. The worst case (explosion on pad; <1% chance) means that Commercial Crew flights may be delayed since they must use LC39A. The F9 is its own tried and true vehicle. FH is a new vehicle--thus, the test flight to rack up flight data.
And what makes you so certain there's <1% chance of an explosion on the pad? Would you have said the same about F9 prior to AMOS-6?
Falcon 9 has had 46 launch attempts, with at least one static fire per launch attempt, plus one additional post-recovery static fire for most of the 20 recovered boosters. So we have well over 100 launch and ignition sequences, which means a single explosion during prop loading (AMOS-6) is still statistically <1%.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Robotbeat on 01/02/2018 12:42 PM

Also understand that the existing F9 or FH PAF can only accomodate up to 24k lbs.  .
This is not correct.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Kaputnik on 01/02/2018 12:51 PM
First time poster.

Regarding the 92% thrust.

Is this not simply because it's an LV capable of lifting 16000kg to MTO that is in fact only lifting off with a 1500kg payload. An LV that can hoist 60000kg off the pad only lifting 1500kg (or whatever the weight of the tesla + mounting is) would go into a massive over g situation within seconds lifting that light a load. As it is I would imagine the 92% will only be until it clears the pad, then a massive throttle down until well past max q and throttling down all the way up. A lot of rockets auto throttle to constant 5g acceleration for structural reasons IIRC. This baby in its maiden config will have plenty of horses to spare.

Or am I wrong on that?

Edit: Does anyone know if there is extra ballast in the payload to counteract this? Or what the actual final payload weight actually will be?

You need to consider payload as a portion of gross lift of mass. Expecting the early stages of flight to be noticeably different due to the small payload is akin to being able to spot a HGV accelerating more quickly just because the driver lost some weight.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Kaputnik on 01/02/2018 12:53 PM
Apologies in case this has been done to death, but am I correct in thinking that the initial FH side boosters are b3 and the core is b4?
What are people's thoughts on the likelihood of each of these cores flying again?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 01/02/2018 01:03 PM
Apologies in case this has been done to death, but am I correct in thinking that the initial FH side boosters are b3 and the core is b4?
What are people's thoughts on the likelihood of each of these cores flying again?

It's possible that both side boosters will be retired after landing while the center core COULD be reused for one reflight before retirement.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: hopalong on 01/02/2018 01:07 PM
Apologies in case this has been done to death, but am I correct in thinking that the initial FH side boosters are b3 and the core is b4?
What are people's thoughts on the likelihood of each of these cores flying again?

I suspect between unlikely and zero.
SpaceX will want to take them apart after recovery to look for any cracks and alike in the load bearing structure and it has already been stated that future Heavies will be block 5 based.   

edited for spelling
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: wannamoonbase on 01/02/2018 01:27 PM
Apologies in case this has been done to death, but am I correct in thinking that the initial FH side boosters are b3 and the core is b4?
What are people's thoughts on the likelihood of each of these cores flying again?

I’ve been thinking about this for awhile and I think it’s possible this FH team of 3 cores gets another flight. 

The 2 Block 3 Cores have been significantly reworked since their first flight, maybe they’ve been reworked enough to be considered fresh.  The core certainly is.

SpaceX could offer a new or existing FH customer to jump the queue with a FH ride.  They have spent a huge amount of money on developing FH and building this specific article.  If they can generate more revenue from this vehicle I think they’ll book a flight, after the Dragon 2 demo and LC39A has an open window.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Oersted on 01/02/2018 01:59 PM
Only with SpaceX do you get people speculating about further flights of a launch vehicle that is about to embark on a perilous first flight... Sign of confidence!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 01/02/2018 02:05 PM
Only with SpaceX do you get people speculating about further flights of a launch vehicle that is about to embark on a perilous first flight... Sign of confidence!

The mission patch shows a guy whistling in the wind while standing under a ladder - they're that confident.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: sevenperforce on 01/02/2018 02:06 PM
First time poster.

Regarding the 92% thrust.

Is this not simply because it's an LV capable of lifting 16000kg to MTO that is in fact only lifting off with a 1500kg payload. An LV that can hoist 60000kg off the pad only lifting 1500kg (or whatever the weight of the tesla + mounting is) would go into a massive over g situation within seconds lifting that light a load. As it is I would imagine the 92% will only be until it clears the pad, then a massive throttle down until well past max q and throttling down all the way up. A lot of rockets auto throttle to constant 5g acceleration for structural reasons IIRC. This baby in its maiden config will have plenty of horses to spare.

Or am I wrong on that?

Edit: Does anyone know if there is extra ballast in the payload to counteract this? Or what the actual final payload weight actually will be?

You need to consider payload as a portion of gross lift of mass. Expecting the early stages of flight to be noticeably different due to the small payload is akin to being able to spot a HGV accelerating more quickly just because the driver lost some weight.
Putting this to rest...

A Falcon 9 first stage masses roughly 22.2 tonnes dry plus 411 tonnes of propellant. A Falcon 9 upper stage masses roughly 4 tonnes with 107.5 tonnes of propellant.

FH's theoretical maximum payload to LEO is 63.8 tonnes.

Thus, a Falcon Heavy with the maximum payload would come in at 1,475 tonnes. A Falcon Heavy with no payload (just a bare upper stage) would come in at 1411 tonnes. Thus, the TWR difference between launching with the maximum expendable LEO payload and no payload at all is just 4.3%. Nothing you'd ever notice.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rsdavis9 on 01/02/2018 02:33 PM
First time poster.

Regarding the 92% thrust.

Is this not simply because it's an LV capable of lifting 16000kg to MTO that is in fact only lifting off with a 1500kg payload. An LV that can hoist 60000kg off the pad only lifting 1500kg (or whatever the weight of the tesla + mounting is) would go into a massive over g situation within seconds lifting that light a load. As it is I would imagine the 92% will only be until it clears the pad, then a massive throttle down until well past max q and throttling down all the way up. A lot of rockets auto throttle to constant 5g acceleration for structural reasons IIRC. This baby in its maiden config will have plenty of horses to spare.

Or am I wrong on that?

Edit: Does anyone know if there is extra ballast in the payload to counteract this? Or what the actual final payload weight actually will be?

You need to consider payload as a portion of gross lift of mass. Expecting the early stages of flight to be noticeably different due to the small payload is akin to being able to spot a HGV accelerating more quickly just because the driver lost some weight.
Putting this to rest...

A Falcon 9 first stage masses roughly 22.2 tonnes dry plus 411 tonnes of propellant. A Falcon 9 upper stage masses roughly 4 tonnes with 107.5 tonnes of propellant.

FH's theoretical maximum payload to LEO is 63.8 tonnes.

Thus, a Falcon Heavy with the maximum payload would come in at 1,475 tonnes. A Falcon Heavy with no payload (just a bare upper stage) would come in at 1411 tonnes. Thus, the TWR difference between launching with the maximum expendable LEO payload and no payload at all is just 4.3%. Nothing you'd ever notice.

and for the second stage the payload fraction at stage 2 ignition is 63.8/(107.4+4)=.57 so much more significant here.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 01/02/2018 04:10 PM
cyndy- That tweet references how the rocket thrust profile will work in general, not how the individual mission thrust profile will be deployed.

The thrust profile tweet was part of the thread announcing the maiden launch when it was planned for November, easily seen in its entirety by clicking on the link I included.

That profile obviously adds up to less than 100%, just as the maiden launch has been confirmed will. Although there is one customer payload currently on the manifest and I don't know what the thrust requirements will be for that one, I doubt they can plan on less than 100% for all time without knowing what their other future payloads will be.

There are at least 2 of us here who think the most logical reason for the lower center thrust is to match or coordinate with a lower maximum thrust on the much older side cores, and it appears the idea of a need to accommodate an underweight payload has been put to rest.

However, an interesting side note is that the Shuttle boosters were routinely responsible for 83% of the full assembly's thrust, if WikiP is to be believed. Whether or not the FH attachment points could or will withstand more discrepancy after the maiden launch has yet to be known.

https://twitter.com/elonmusk/status/890810308326940672
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 01/02/2018 04:19 PM
That profile obviously adds up to less than 100%, just as the maiden launch has been confirmed will.

Throttling down the center core early in flight will happen on every FH launch, that is what the vehicle is designed to do.  That part has nothing to do with the max thrust of the vehicle on any particular flight.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 01/02/2018 04:36 PM
That profile obviously adds up to less than 100%, just as the maiden launch has been confirmed will.

Throttling down the center core early in flight will happen on every FH launch, that is what the vehicle is designed to do.  That part has nothing to do with the max thrust of the vehicle on any particular flight.

ok
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: UKobserver on 01/02/2018 04:47 PM
The 92% thrust level might only be for this mission.

I've wondered if the thrust "reduction" on this mission is just because he's giving thrust numbers for FH Block 5 and this vehicle is running at Block 3 levels.

There was some discussion about this in the Merlin 1D update thread a few days ago;

https://forum.nasaspaceflight.com/index.php?topic=41014.200

It was prompted by the following Instagram post from a SpaceX employee, showing off a new Block 5 booster engine, which he claimed was rated at 205,000lbf.

https://www.instagram.com/p/Bc8pqAng9rH/

While there have been suggestions that these new engines may have actually been tested on the stand at thrust levels as high as 245,000lbf, presumably to establish safety margins, it looks like they will be introducing a new flight rating of 205,000lbf when these engines debut on the new block 5 booster.

This first FH is a composite of B3 side boosters and a B4 core, whose Merlin 1Ds I believe run at 190,000lbf thrust. AncientU pointed out that 27 x 190,000lbf is 5.1Mlbf, which matches the thrust that Elon said FH would have at liftfoff.

190,000 is 92% of 205,000, so those facts combined would suggest that this first test will run at what are normal thrust levels for each of the respective cores (albeit that the centre core will throttle down after lift-off), but that the total thrust available on this flight is only 92% of what a full-up Block 5 Falcon Heavy will be capable of.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 01/02/2018 04:58 PM
Good sleuthing! 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 01/02/2018 05:05 PM
There was some discussion about this in the Merlin 1D update thread a few days ago;

https://forum.nasaspaceflight.com/index.php?topic=41014.200

It was prompted by the following Instagram post from a SpaceX employee, showing off a new Block 5 booster engine, which he claimed was rated at 205,000lbf.

https://www.instagram.com/p/Bc8pqAng9rH/

While there have been suggestions that these new engines may have actually been tested on the stand at thrust levels as high as 245,000lbf, presumably to establish safety margins, it looks like they will be introducing a new flight rating of 205,000lbf when these engines debut on the new block 5 booster.

On the SpaceX web site it shows thrust at sea level of 190k lbf and thrust in vacuum of 205k lbf.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 01/02/2018 05:09 PM
Good sleuthing!

No kidding! That certainly explains everything! Good to know & understand!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Formica on 01/02/2018 05:17 PM

This first FH is a composite of B3 side boosters and a B4 core, whose Merlin 1Ds I believe run at 190,000lbf thrust. AncientU pointed out that 27 x 190,000lbf is 5.1Mlbf, which matches the thrust that Elon said FH would have at liftfoff.


1033.1, the center core, is definitely based on Block 3 tech. 1023.2 and 1025.2 started life as Block 2, and may have been upgraded to Block 3 tech in the same way that 1021.2 was for its reflight. There was an intern from KSC who posted on Reddit about upgrading 1021.2 during its refurbishment, describing the process of replacing Block 1 parts with Block 3 parts. I'm still looking for a link to that post.

Here's a community based spreadsheet (https://docs.google.com/spreadsheets/d/1N8AaRRaPyVZZ2Rxpe9lWEFXWIyRqAJqXJ--TqHuhBYw/htmlview), with references, that keeps track of the blocks. It is as accurate as it can be without input from SpaceX, as far as I can tell.

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 01/02/2018 05:31 PM
Good sleuthing!

It's really not.  The 190k lbf is the sea level thrust of Block 5, not Block 3.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 01/02/2018 05:51 PM
Well the current booster engine has 190k lbf, the instagrammed booster engine has 205k lbf. One is 92% of the other.

I don't think we ever got to the bottom of the instagrammed engine, but Elons 92% tweet makes me think that it really had been uprated to 205k. Which I was doubting as there could have been some confusion between booster and vacuum engines.

The only info we have is from keeping a close watch on the public internet and waiting for more into from Spacex/Elon. But in reference to FH it's reasonable to think that this launch will have 190k lbf Merlin D engines while then next block 5 FH will have 205k lbf Merlin D engines.

We'll have to keep trawling social media for clues! :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 01/02/2018 05:54 PM
Well the current booster engine has 190k lbf, the instagrammed booster engine has 205k lbf. One is 92% of the other.

I don't think we ever got to the bottom of the instagrammed engine, but Elons 92% tweet makes me think that it really had been uprated to 205k. Which I was doubting as there could have been some confusion between booster and vacuum engines.

The only info we have is from keeping a close watch on the public internet and waiting for more into from Spacex/Elon. But in reference to FH it's reasonable to think that this launch will have 190k lbf Merlin D engines while then next block 5 FH will have 205k lbf Merlin D engines.

We'll have to keep trawling social media for clues! :)

The Block 5 values as shown on the SpaceX web site are 190k/sea level, 205k/vacuum.  For the same first stage engines.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 01/02/2018 06:12 PM
I took a look at the falcon 9 (http://www.spacex.com/falcon9) page but couldn't determine the model of F9 it was referring to, so I assumed it was the current one, not B5.

I could be wrong though.

I also noted that Vac M1D has a thrust of 210k lbs, when I thought it had 205k, so yeah I could be getting rather confused.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RocketLover0119 on 01/02/2018 06:20 PM
Chris B on the ZUMA update thread says there is a potential 2nd SF coming up, if so, that would definitely push back the FH SF this week.....
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: UKobserver on 01/02/2018 07:04 PM
Well the current booster engine has 190k lbf, the instagrammed booster engine has 205k lbf. One is 92% of the other.

I don't think we ever got to the bottom of the instagrammed engine, but Elons 92% tweet makes me think that it really had been uprated to 205k. Which I was doubting as there could have been some confusion between booster and vacuum engines.

The only info we have is from keeping a close watch on the public internet and waiting for more into from Spacex/Elon. But in reference to FH it's reasonable to think that this launch will have 190k lbf Merlin D engines while then next block 5 FH will have 205k lbf Merlin D engines.

We'll have to keep trawling social media for clues! :)

The Block 5 values as shown on the SpaceX web site are 190k/sea level, 205k/vacuum.  For the same first stage engines.

I'm not disagreeing, as it's completely plausible that the SpaceX website is showing B5 stats and that the employee was referring to thrust level in a vacuum, but are you suggesting that it's just a massive co-incidence that they are running at 92% this time? Why 92%? And 92% of what?

Is S/L thrust also 92% of vacuum thrust for previous versions of the M1D, such as on the B2 and B3 boosters? Is that due to the expansion ratio of the nozzle? If so, does Elon mean that they are going to gradually throttle down each engine as this FH climbs so as to keep the maximum thrust from each engine at S/L thrust levels all the way through the flight, perhaps for structural reasons?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 01/02/2018 07:11 PM
I'm not disagreeing, as it's completely plausible that the SpaceX website is showing B5 stats and that the employee was referring to thrust level in a vacuum, but are you suggesting that it's just a massive co-incidence that they are running at 92% this time?
Yes

Quote
Why 92%?
I don't know

Quote
And 92% of what?
5.1M lbf

Quote
Is S/L thrust also 92% of vacuum thrust for previous versions of the M1D, such as on the B2 and B3 boosters?
The previous value I see from their site is 170k lbf @ SL/185k lbf @ vacuum, so yes.

Quote
Is that due to the expansion ratio of the nozzle? If so, does Elon mean that they are going to gradually throttle down each engine as this FH climbs so as to keep the maximum thrust from each engine at S/L thrust levels all the way through the flight, perhaps for structural reasons?
I'm assuming Elon was talking about thrust at lift-off, period.  Engines throttle to various settings during flight as needed (around Max-Q, limiting acceleration as the vehicle gets lighter, etc.)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/02/2018 07:24 PM
Quote
Why 92%?
I don't know

92% of what the website lists is about what all the 2017 flights have been running at - see the sims thread. I'm guessing it's what Block 3 and 4 cores are rated for, since SpaceX used to list Merlin at 170 klbf at liftoff (89.5% of 190 klbf). This would seem to apply to all early blocks of FT/v1.2, with only Block 5 getting a thrust upgrade.

https://web.archive.org/web/20160101081059/http://www.spacex.com/falcon9
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: UKobserver on 01/02/2018 07:29 PM
I'm not disagreeing, as it's completely plausible that the SpaceX website is showing B5 stats and that the employee was referring to thrust level in a vacuum, but are you suggesting that it's just a massive co-incidence that they are running at 92% this time?
Yes

Quote
Why 92%?
I don't know

Quote
And 92% of what?
5.1M lbf

Quote
Is S/L thrust also 92% of vacuum thrust for previous versions of the M1D, such as on the B2 and B3 boosters?
The previous value I see from their site is 170k lbf @ SL/185k lbf @ vacuum, so yes.

Quote
Is that due to the expansion ratio of the nozzle? If so, does Elon mean that they are going to gradually throttle down each engine as this FH climbs so as to keep the maximum thrust from each engine at S/L thrust levels all the way through the flight, perhaps for structural reasons?
I'm assuming Elon was talking about thrust at lift-off, period.  Engines throttle to various settings during flight as needed (around Max-Q, limiting acceleration as the vehicle gets lighter, etc.)

Thanks, that's useful to know re earlier models/expansion ratio. I really doubt that 92% is a co-incidence though; I can't imagine anyone picking that exact number unless it matched up with something, like the difference between maximum thrust levels of the side and core boosters, or structural limits, or something else. I also think Elon would have explicitly stated that S/L thrust was 92% of that produced in a vacuum if he meant it that way. I could be completely wrong but I interpreted his statement as meaning that at some point in flight the thrust levels will be only 92% of either, a) what these engines are actually capable of producing, or b) what the B5 engines will be capable of producing, at that same point in flight. But who knows.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: MP99 on 01/02/2018 07:32 PM
It's safe to say that this will be only Falcon Heavy ever to use pre-Block 5 cores. After re-scoping Falcon Heavy to chase F9 iterations to v1.1 and then to FT specifications, now there's Block 5 coming. SpaceX needed to make the decision whether to bring the FH demo vehicle up to Block 5 spec with bolted octowebs etc. and accept further delays to a program already repeatedly delayed by F9 iteration churn -- or to simply launch the damn thing already even though it will end up being a one-off. This will forever be the unique "albino" FH demo vehicle.
I believe that the initial flight is using pre-block-5 cores because there is some question whether it will reach orbit.

I believe all following flights will be block 5 because they expect to learn enough from flight #1 that subsequent flights have a much better chance of succeeding.

Cheers, Martin

Sent from my GT-N5120 using Tapatalk

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 01/02/2018 07:41 PM
It's safe to say that this will be only Falcon Heavy ever to use pre-Block 5 cores. After re-scoping Falcon Heavy to chase F9 iterations to v1.1 and then to FT specifications, now there's Block 5 coming. SpaceX needed to make the decision whether to bring the FH demo vehicle up to Block 5 spec with bolted octowebs etc. and accept further delays to a program already repeatedly delayed by F9 iteration churn -- or to simply launch the damn thing already even though it will end up being a one-off. This will forever be the unique "albino" FH demo vehicle.
I believe that the initial flight is using pre-block-5 cores because there is some question whether it will reach orbit.

I believe all following flights will be block 5 because they expect to learn enough from flight #1 that subsequent flights have a much better chance of succeeding.

Cheers, Martin

The initial flight is using pre-Block 5 cores because it was meant to fly before Block 5 was ready.  Block 5 was never a requirement for FH.  All following flights will be Block 5 because all of the cores they'll be building will be Block 5.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisGebhardt on 01/02/2018 09:31 PM
That moment when you find a poll with your name on it and you've got the most votes and you go "What?"

But yes, I'll happily take charge of organizing something surrounding Falcon Heavy.  I'll be at KSC press site for the launch, but as we'll likely have A LOT of people coming for this, maybe I can dust off the old Shuttle dinner gatherings I used to organize and we can see who all wants to meet up for dinner/drinks the night before the first launch?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: OnWithTheShow on 01/03/2018 12:02 AM
maybe I can dust off the old Shuttle dinner gatherings I used to organize and we can see who all wants to meet up for dinner/drinks the night before the first launch?

Dixie Crossroads?
Im gonna try to make it down.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: OneSpeed on 01/03/2018 12:31 AM
92% of what the website lists is about what all the 2017 flights have been running at - see the sims thread. I'm guessing it's what Block 3 and 4 cores are rated for, since SpaceX used to list Merlin at 170 klbf at liftoff (89.5% of 190 klbf). This would seem to apply to all early blocks of FT/v1.2, with only Block 5 getting a thrust upgrade.

https://web.archive.org/web/20160101081059/http://www.spacex.com/falcon9

Yes, most of the Block 3 and 4 sims are at 91% thrust up to and after throttle down for max-Q. What this tells me is that my mass estimate for F9 is about 1% too low, so I will be updating that figure.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mdeep on 01/03/2018 01:56 AM
But yes, I'll happily take charge of organizing something surrounding Falcon Heavy.  I'll be at KSC press site for the launch, but as we'll likely have A LOT of people coming for this, maybe I can dust off the old Shuttle dinner gatherings I used to organize and we can see who all wants to meet up for dinner/drinks the night before the first launch?

Always meant to go to one of these. As long as it doesn't conflict with remotes, I'll definitely try to join in.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Flying Beaver on 01/03/2018 02:18 AM
...who all wants to meet up for dinner/drinks the night before the first launch?

Well I look forward to joining everyone for every evening for a week or 2 week (plus) in that case  ;D.

(Kinda) Just joking, i'm sure they'll fly on the first or second attempt if the static fire goes well.

Was able to eye up the OG-2 F2 launch date well enough (one day off but punted 24hrs, in line with Elon :P) that i'd be confident getting plane tickets after a static fire confirmation, in line with the best estimates of launch date at that point, plus a 5/6 day buffer.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Flying Beaver on 01/03/2018 03:11 AM
Interesting detail from the pad pics are these three points on all the cores, facing the same way, even with the west booster being rotated 180degs. I assume these are telemetry transmitters? As they would be facing downwards as the vehicle pitches over during accent.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: oiorionsbelt on 01/03/2018 03:34 AM
Interesting detail from the pad pics are these three points on all the cores, facing the same way, even with the west booster being rotated 180degs. I assume these are telemetry transmitters? As they would be facing downwards as the vehicle pitches over during accent.
Speaking of one booster being rotated 180degrees. Couldn't help but notice these.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisC on 01/03/2018 03:58 AM
But yes, I'll happily take charge of organizing something surrounding Falcon Heavy.  I'll be at KSC press site for the launch, but as we'll likely have A LOT of people coming for this, maybe I can dust off the old Shuttle dinner gatherings I used to organize and we can see who all wants to meet up for dinner/drinks the night before the first launch?

Mods, split these meetup posts to a new thread, like the old STS launch days?

EDIT -- the new thread is here: https://forum.nasaspaceflight.com/index.php?topic=44587.0
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: allio on 01/03/2018 05:14 AM
Was thinking the other day, How cool would five foot plushies of Jebediah, Bill, Bob and valentina strapped into the front of the tesla be?

AWESOME!
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ugordan on 01/03/2018 08:44 AM
Interesting detail from the pad pics are these three points on all the cores, facing the same way, even with the west booster being rotated 180degs.

Note also something that looks like a wire in the leftmost two cores coming out of that same section. Wonder if its some instrumentation for the static fire because it doesn't look secure enough for a flight environment, but then why paint the wiring white?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: bdub217 on 01/03/2018 01:59 PM
I am interesting in seeing how big the initial launch window will be when the launch date is posted. Clearly there should be no operational restraints for launching a tesla in the general vicinity of a martian heliocentric orbit. I'd also imagine they'd want plenty of time to call a delay if anything should look unusual. That said - wouldn't an especially  lengthy active launch window negatively impact air and sea navigation around the cape?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ben the Space Brit on 01/03/2018 02:06 PM
Are there any viable slingshot orbits to enable trans-Martian injection coming up (via Venus or the Moon perhaps)?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 01/03/2018 02:52 PM
AIUI the inclination-from-the-ecliptic difference between Earth and Mars is "maximally bad" this month, so you'd either have to do something fancy---or else refire S2 after a couple months of coasting.

I'm starting to be persuaded that the "fancy" orbit is just a "simple" apogee-at-Mars-distance elliptical orbit, and the inclination difference is going to be sold as a planetary-protection "feature".
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jacqmans on 01/03/2018 03:19 PM
That moment when you find a poll with your name on it and you've got the most votes and you go "What?"

But yes, I'll happily take charge of organizing something surrounding Falcon Heavy.  I'll be at KSC press site for the launch, but as we'll likely have A LOT of people coming for this, maybe I can dust off the old Shuttle dinner gatherings I used to organize and we can see who all wants to meet up for dinner/drinks the night before the first launch?

Dixie Crossroads like with the shuttle, you might want to count me in ;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/03/2018 04:28 PM
Are there any viable slingshot orbits to enable trans-Martian injection coming up (via Venus or the Moon perhaps)?

There's no particular reason to do this. SpaceX can define a reference orbit that is similar to a TMI, and see how close the actual injection is relative to that target. No point in running any chance of actually hitting Mars down the road.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisGebhardt on 01/03/2018 06:07 PM
But yes, I'll happily take charge of organizing something surrounding Falcon Heavy.  I'll be at KSC press site for the launch, but as we'll likely have A LOT of people coming for this, maybe I can dust off the old Shuttle dinner gatherings I used to organize and we can see who all wants to meet up for dinner/drinks the night before the first launch?

Always meant to go to one of these. As long as it doesn't conflict with remotes, I'll definitely try to join in.

It definitely won't as it'll have to be around all the media events that I'll be at, too.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisGebhardt on 01/03/2018 06:30 PM
With confirmation that there's a good deal of interest in having an NSF member meet up for Falcon Heavy's debut, I've started a dedicated thread for that.

https://forum.nasaspaceflight.com/index.php?topic=44587.new#new
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: CyndyC on 01/04/2018 01:53 AM
AIUI the inclination-from-the-ecliptic difference between Earth and Mars is "maximally bad" this month, so you'd either have to do something fancy---or else refire S2 after a couple months of coasting.

I'm starting to be persuaded that the "fancy" orbit is just a "simple" apogee-at-Mars-distance elliptical orbit, and the inclination difference is going to be sold as a planetary-protection "feature".

There is also the question is that going to be close enough to Mars orbit for Elon Musk and enough SpaceX employees? If they delay the launch further just to get closer to Mars orbit, till late February as you said in a previous post on this topic, employees who don't care as much where the Roadster ends up and the public would only be disappointed for another 50 days, whereas if they don't delay the launch, Elon and employees who do care where the Roadster ends up would be disappointed for a billion years. I'm serious  ;)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 01/04/2018 02:58 AM
AIUI the inclination-from-the-ecliptic difference between Earth and Mars is "maximally bad" this month, so you'd either have to do something fancy---or else refire S2 after a couple months of coasting.

I'm starting to be persuaded that the "fancy" orbit is just a "simple" apogee-at-Mars-distance elliptical orbit, and the inclination difference is going to be sold as a planetary-protection "feature".
Mars is quite far away at the moment - 16.15 light minutes distance, in a telescope 4.8 arc seconds, about 3/4 of the furthest it can get from earth. Visible low in the morning sky.

Opposition is July 26th, when they will be 3.22 light minutes apart and 24.2 arc seconds. Insight will launch May 5th to transit optimally.

If you want to make it to Mars, you'll wait on your launch to later this year. Now, if you want the long transit time with an encounter (no props to assist capture),  you don't need to wait to May to do so, but you still need to wait.

(Yes you could conceive of an aerobrake by skimming the Tesla through the low atmosphere, possibly melting portions of it, which might lose enough delta-v to be captured into an orbit around Mars, but given that you'd like to minimize encounter velocity you'd have to wait close to a year and a half so as to launch and encounter Mars 180 degrees apart (too late for this opposition, would have had to happen many months ago - see more in Earth--Mars Transfers with Ballistic Capture (https://arxiv.org/abs/1410.8856)). As it's the wrong shape for entry, the tumbling would be unpredictable so you'll have a large sheaf of possible trajectories depending on how the payload gyrates during entry and ends up exitting the atmosphere, likely to re encounter it again with similar instabilities.)

In any event, you'd need a GNC with thruster package around center of mass, to do mid course corrections. And, in keeping with planetary protection protocols, you'd have to insure a clean miss with your mission operations team until your final commit to encounter, likely a month or so out. Oh, and you'll need DSN time to track/communicate such corrections and to monitor.

So much for bringing "Mars the planet" into the picture - work, work, work. Much better to just transit it's heliocentric distance from the sun, and not have to worry about all that and niggling things like being in the plane of the orbit, at a time when that might complicate ascent and ground tracking from the same location as launch ...
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: freda on 01/04/2018 02:33 PM
Interesting detail from the pad pics are these three points on all the cores, facing the same way, even with the west booster being rotated 180degs. I assume these are telemetry transmitters? As they would be facing downwards as the vehicle pitches over during accent.

Similar artifacts also shown on S2.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: nacnud on 01/04/2018 02:38 PM
We're gonna need a four picture split screen to watch all those downlinked vids! Plus one for the Tesla!  8)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Surfdaddy on 01/04/2018 05:20 PM
1 - Do we know if this is going to a direct TMI (or Mars-distance orbital injection) or whether they'll coast in earth orbit for a bit?
2 - I would assume for publicity purposes that Elon will have arranged an epic live video shot of the Tesla payload separating from the upper stage. Or do we think that they'll just have it remain attached to stage 2 for total simplicity?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 01/04/2018 05:41 PM
Consensus seems to be direct injection and no separation, but there's no a lot of evidence either way. Only: longest S2 coast was for DSCOVR (30 min) & it would require S2 modifications for significantly longer; and no obvious hardware on the roadster (solar panels, comm antennas) to support a mission apart from the S2. Of course there could be surprises.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 01/04/2018 05:46 PM
1 - Do we know if this is going to a direct TMI (or Mars-distance orbital injection) or whether they'll coast in earth orbit for a bit?
2 - I would assume for publicity purposes that Elon will have arranged an epic live video shot of the Tesla payload separating from the upper stage. Or do we think that they'll just have it remain attached to stage 2 for total simplicity?
1. They won't coast because they need to stay in range as long as possible to get tracking from Florida assets nothing elsewhere.
2. Very likely it'll remain with F9US because it's easier to track, has active control/telemetry for the life of the stage, and deals with disposal of stage.

Consensus seems to be direct injection and no separation, but there's no a lot of evidence either way. Only: longest S2 coast was for DSCOVR (30 min) & it would require S2 modifications for significantly longer; and no obvious hardware on the roadster (solar panels, comm antennas) to support a mission apart from the S2. Of course there could be surprises.
Attitude controls for a Tesla?  :o
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Brian45 on 01/04/2018 06:00 PM
Someone mentioned here that under a certain scenario, the S2 might need to fire for a Mars course correction quite a while after launch. Seems to me this would be an excellent opportunity to gather some more data points for the performance of the S2 engine under unique conditions.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 01/04/2018 06:10 PM
Someone mentioned here that under a certain scenario, the S2 might need to fire for a Mars course correction quite a while after launch.
Too early for a significant course correction.

Where it is heading isn't Mars but Mars-like in distance/reach, so you don't need a course correction at all to get there.

What you could do is at furthest range do a burn to insure that the payload+F9US wasn't captured by the earth-moon system, but that would be chancy because it isn't the right geometry at the moment for various reasons.

Quote
Seems to me this would be an excellent opportunity to gather some more data points for the performance of the S2 engine under unique conditions.
The F9US would have to be outfitted for long duration. No signs of that at the moment.

And they'd have to have tracking assets to allow such, and that does not yet appear to be arranged for.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Brian45 on 01/04/2018 06:24 PM
Well, it was just a thought. Eventually SpaceX will need to develop and/or ensure the capability of firing the engine after extended periods (days, weeks, months?) in space, so maybe someone at SpaceX said - what the heck, what do we have to lose?

Have they ever done this, firing the engine after a long period?

Again, just a thought. Maybe a little off-topic though.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: kevinof on 01/04/2018 06:34 PM
Batteries won't last that long and there's no other way to generate power.

Well, it was just a thought. Eventually SpaceX will need to develop and/or ensure the capability of firing the engine after extended periods (days, weeks, months?) in space, so maybe someone at SpaceX said - what the heck, what do we have to lose?

Have they ever done this, firing the engine after a long period?

Again, just a thought. Maybe a little off-topic though.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisC on 01/04/2018 06:35 PM
FYI, someone who monitors the Facebook SpaceX group tells me they are saying that Playalinda Beach will be closed for the FH launch.  So, that's third hand information, but I thought it worth mentioning here because I have seen no such report here, just that we don't know yet either way.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/04/2018 07:15 PM
1 - Do we know if this is going to a direct TMI (or Mars-distance orbital injection) or whether they'll coast in earth orbit for a bit?
2 - I would assume for publicity purposes that Elon will have arranged an epic live video shot of the Tesla payload separating from the upper stage. Or do we think that they'll just have it remain attached to stage 2 for total simplicity?
1. They won't coast because they need to stay in range as long as possible to get tracking from Florida assets nothing elsewhere.
2. Very likely it'll remain with F9US because it's easier to track, has active control/telemetry for the life of the stage, and deals with disposal of stage.

Consensus seems to be direct injection and no separation, but there's no a lot of evidence either way. Only: longest S2 coast was for DSCOVR (30 min) & it would require S2 modifications for significantly longer; and no obvious hardware on the roadster (solar panels, comm antennas) to support a mission apart from the S2. Of course there could be surprises.
Attitude controls for a Tesla?  :o

If they inject directly into heliocentric orbit the apoapsis will be significantly out of the ecliptic and very far away from Mars. This might not be a bad thing, but it's not really a Mars-like orbit.

All GTO launches coast for about 1/4 orbit and relight over the equator. SpaceX obviously has the necessary tracking assets to do this, and even streams live video from the S2 over Africa, well out of range of the Florida stations. I see no reason why the TMI burn wouldn't also occur over Africa.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: 1 on 01/04/2018 08:45 PM
If they inject directly into heliocentric orbit the apoapsis will be significantly out of the ecliptic and very far away from Mars. This might not be a bad thing, but it's not really a Mars-like orbit.

All GTO launches coast for about 1/4 orbit and relight over the equator. SpaceX obviously has the necessary tracking assets to do this, and even streams live video from the S2 over Africa, well out of range of the Florida stations. I see no reason why the TMI burn wouldn't also occur over Africa.

I imagine the equator is of little use for this launch, because the Earth is tilted a good 23ish degrees from the plane of the ecliptic.

(http://1.bp.blogspot.com/-fI0BeZ44DeU/ToJxftzfnkI/AAAAAAAAAXY/DkDDdwLHpbg/s1600/earth+lines.gif)

As such, I assume SpaceX won't do much more than wait until the Earth rotates the rocket near the plane of the ecliptic and then just go for direct injection. Could probably zero out that 4 degree difference pretty easily if they really wanted to; but I too think that they'll deliberately send the stage slightly off-plane so they can guarantee that it will never hit Mars.

If they do need to go to an intermediate parking orbit, I think 23.5 degree is what they'd need to aim for.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Heinrich on 01/04/2018 08:55 PM
In case the above post (by 1) is right, what will the approximate launch time?
(Would be nice to know whether it will be within or outside of office hours)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: atsf90east on 01/04/2018 09:05 PM
If Zuma is delayed until Sunday will the FH static fire at LC39A still happen on Saturday, or will it be pushed back until Zuma launches from LC40 so that manpower is not stretched too thin?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 01/04/2018 09:13 PM
If Zuma is delayed until Sunday will the FH static fire at LC39A still happen on Saturday, or will it be pushed back until Zuma launches from LC40 so that manpower is not stretched too thin?
They could do it as currently scheduled but there a risk factor with ZUMA soon rolling to SLC-40 for PI. Will know sooner rather than later if they officially bump ZUMA to Sunday.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Celestar on 01/04/2018 09:22 PM
Batteries won't last that long and there's no other way to generate power.

There's something else on board that has some relatively huge batteries ...

Celestar
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 01/04/2018 09:28 PM
If they inject directly into heliocentric orbit the apoapsis will be significantly out of the ecliptic and very far away from Mars. This might not be a bad thing, but it's not really a Mars-like orbit.
Yes expect direct injection - am very interested in how much C3 a kerolox cluster vehicle can impart.

If they launch in the late evening during December, they can direct inject close to optimal with Earth's orbital velocity in a "Mars-like" transfer orbit, a little above the plane. If they launch during the day, it'll be closer to the ecliptic but more out of plane with Mars, and likely an launch azimuth above 90.

Quote
All GTO launches coast for about 1/4 orbit and relight over the equator. SpaceX obviously has the necessary tracking assets to do this, and even streams live video from the S2 over Africa, well out of range of the Florida stations. I see no reason why the TMI burn wouldn't also occur over Africa.
Yes closer to the equator obviously will be better, but I wonder if only Florida tracking will be used for this launch.

In that case if they coast then they'll be over the horizon and have to use those other assets.

There are some advantages to keeping it all in the range. Especially for a new vehicle.

If Zuma is delayed until Sunday will the FH static fire at LC39A still happen on Saturday, or will it be pushed back until Zuma launches from LC40 so that manpower is not stretched too thin?

We don't know the issues that remain with the vehicle. Could be they need more time anyways. Which could also stretch static fire, as well as after static fire. Frankly I'm already amazed its assembled and having been erected at the pad so quickly. This isn't something that goes fast. Ever.

If Zuma is delayed until Sunday will the FH static fire at LC39A still happen on Saturday, or will it be pushed back until Zuma launches from LC40 so that manpower is not stretched too thin?
They could do it as currently scheduled but there a risk factor with ZUMA soon rolling to SLC-40 for PI. Will know sooner rather than later if they officially bump ZUMA to Sunday.
Speaking of the slowest of slow boats ... will this thing ever go? A real "high touch" mission ... <groan>.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: 1 on 01/04/2018 09:34 PM
In case the above post (by 1) is right, what will the approximate launch time?
(Would be nice to know whether it will be within or outside of office hours)

My WAG is that a direct injection launch in late January (approximately one month later) would happen somewhere around 22:00 Florida time. This is nothing more than running with the approximation that the "tipping over" of the northern hemisphere during southern solstice is centered at local midnight. After a month, that point should be about two hours earlier going with the normal 4 minute/day differential between sidereal time and civil time. Complete guess on my part; so don't plan your schedule around that.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: kevinof on 01/04/2018 09:39 PM
I doubt there are any batteries in the car and anyway they would need to be heated someway to get them to work good (I should know!). You would also need to connect it to the S2 which is not something they would do for a one shot deal.

Batteries won't last that long and there's no other way to generate power.

There's something else on board that has some relatively huge batteries ...

Celestar
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: LouScheffer on 01/04/2018 11:08 PM
In case the above post (by 1) is right, what will the approximate launch time?
(Would be nice to know whether it will be within or outside of office hours)

My WAG is that a direct injection launch in late January (approximately one month later) would happen somewhere around 22:00 Florida time. This is nothing more than running with the approximation that the "tipping over" of the northern hemisphere during southern solstice is centered at local midnight. After a month, that point should be about two hours earlier going with the normal 4 minute/day differential between sidereal time and civil time. Complete guess on my part; so don't plan your schedule around that.

My guess would be about 6:00 PM (18:00) local time.  My reasoning is this:  injection is most efficient when exactly the opposite of the intended target.  To get maximum throw, they need the target to be tangent to the Earth's orbit.   This puts the opposite point at about 18:00 local time.   This is only true for direct injection - with a parking orbit, the earth departure burn needs to happen about 18:00 local time (in the probe's time zone) but the launch can be anytime.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Skylab on 01/04/2018 11:15 PM
A tweet showing the positions and workings of the holddown clamps. This seemed like the best place for it.

https://twitter.com/joebarnard/status/949059630352642048
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 01/04/2018 11:27 PM
That's just ... wildly inaccurate.  :P (Sure, there are 3 cores and 8 hold-downs, but everything else is way off)

EDIT: Looks like it is a closeup of a design for a FH model and its 3d printed pad hold downs. Here is a video clip a launch of a single core model: https://twitter.com/joebarnard/status/924506150254665729
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/05/2018 02:41 AM
If they inject directly into heliocentric orbit the apoapsis will be significantly out of the ecliptic and very far away from Mars. This might not be a bad thing, but it's not really a Mars-like orbit.

All GTO launches coast for about 1/4 orbit and relight over the equator. SpaceX obviously has the necessary tracking assets to do this, and even streams live video from the S2 over Africa, well out of range of the Florida stations. I see no reason why the TMI burn wouldn't also occur over Africa.

I imagine the equator is of little use for this launch, because the Earth is tilted a good 23ish degrees from the plane of the ecliptic.

(http://1.bp.blogspot.com/-fI0BeZ44DeU/ToJxftzfnkI/AAAAAAAAAXY/DkDDdwLHpbg/s1600/earth+lines.gif)

As such, I assume SpaceX won't do much more than wait until the Earth rotates the rocket near the plane of the ecliptic and then just go for direct injection. Could probably zero out that 4 degree difference pretty easily if they really wanted to; but I too think that they'll deliberately send the stage slightly off-plane so they can guarantee that it will never hit Mars.

If they do need to go to an intermediate parking orbit, I think 23.5 degree is what they'd need to aim for.

Good point. They would still need a second burn to reduce inclination to 23.5 degrees, but it would happen over the Atlantic somewhere, before reaching Africa. Or just inject directly and stay 4+ degrees out of plane.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/05/2018 02:44 AM
In case the above post (by 1) is right, what will the approximate launch time?
(Would be nice to know whether it will be within or outside of office hours)

My WAG is that a direct injection launch in late January (approximately one month later) would happen somewhere around 22:00 Florida time. This is nothing more than running with the approximation that the "tipping over" of the northern hemisphere during southern solstice is centered at local midnight. After a month, that point should be about two hours earlier going with the normal 4 minute/day differential between sidereal time and civil time. Complete guess on my part; so don't plan your schedule around that.

My guess would be about 6:00 PM (18:00) local time.  My reasoning is this:  injection is most efficient when exactly the opposite of the intended target.  To get maximum throw, they need the target to be tangent to the Earth's orbit.   This puts the opposite point at about 18:00 local time.   This is only true for direct injection - with a parking orbit, the earth departure burn needs to happen about 18:00 local time (in the probe's time zone) but the launch can be anytime.

Shouldn't that be midnight local time? For a Hohmann transfer, apoapsis and periapsis are on opposite sides of the sun, and the tangent to Earth is on the far side from the Sun.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Johnnyhinbos on 01/05/2018 02:58 AM
Okay, so... and it ain’t going to be me due to the 12 SpaceX limit poll thread - but maybe it’s time for an unofficial poll - will the Tesla payload separate from the Falcon Heavy second stage?

I say yes - here’s my logic...

- Payload adapter. If you examine the photos, there seems to me to be separation mechanisms. Why add if not separating?

- Fairing. Even though not fully installed in the photos, why go through the expense to put in a fairing separation system if the payload will stay attached to the second stage?

(Okay, fine, that second point is easily arguable. Proof of concept, weight, photo op - there, I did it for you)

Regardless - my vote is separation. I simply don’t see it any other way. I can only see Elon wanting the Tesla in a slow tumble away from camera. Sorry - it’s just the only way I see it...

Edit/Lar: no such poll limit... this doesn't seem a good topic for a poll though.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: LouScheffer on 01/05/2018 03:10 AM
My guess would be about 6:00 PM (18:00) local time.  My reasoning is this:  injection is most efficient when exactly the opposite of the intended target.  To get maximum throw, they need the target to be tangent to the Earth's orbit.   This puts the opposite point at about 18:00 local time.   This is only true for direct injection - with a parking orbit, the earth departure burn needs to happen about 18:00 local time (in the probe's time zone) but the launch can be anytime.

Shouldn't that be midnight local time? For a Hohmann transfer, apoapsis and periapsis are on opposite sides of the sun, and the tangent to Earth is on the far side from the Sun.

You want to leave Earth at midnight local time, but the way to do that is to burn at 18:00 local time, then the Earth bends the trajectory around 1/4 turn.   To see this, imagine a super long and skinny orbit around the Earth with a 40,000,000 km apogee.  If the long axis of this orbit is tangent to the Earth's orbit, then the perigee is at the trailing edge of Earth, or about 18:00 local time.  Since firing at perigee is the most efficient time, that's where the injection should be.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: MP99 on 01/05/2018 07:47 AM


If they inject directly into heliocentric orbit the apoapsis will be significantly out of the ecliptic and very far away from Mars. This might not be a bad thing, but it's not really a Mars-like orbit.
Yes expect direct injection - am very interested in how much C3 a kerolox cluster vehicle can impart.

This mission seems to be launching a very light payload to a C3 far short of what should be possible. (Unless there's a lot of ballast?)

Does this really demonstrate FH's capabilities?

Cheers, Martin












Sent from my GT-N5120 using Tapatalk

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: hkultala on 01/05/2018 07:58 AM


If they inject directly into heliocentric orbit the apoapsis will be significantly out of the ecliptic and very far away from Mars. This might not be a bad thing, but it's not really a Mars-like orbit.
Yes expect direct injection - am very interested in how much C3 a kerolox cluster vehicle can impart.

This mission seems to be launching a very light payload to a C3 far short of what should be possible. (Unless there's a lot of ballast?)

Does this really demonstrate FH's capabilities?

Yes, it demostrates capability to:
1) clear the pad and reach orbit with the 27 1st stage engines
2) two boosters to simultaneously RTLS
3) center core to do deorbit burn and land on barge from much higher velocity than what was has been done during F9 missions. Actually this light >C3 payload maximizes the velocity for the center core, making it harder than for average FH (military satellite) payload mission.
4) guidance system to push payloads into precise trajectories going very far away


The fact that is does not use all the fuel/lifting capacity available does not matter. If there would be something wrong decreasing the capacity, they would notice it because their tanks would ocntain less fuel than what they have calculated.

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: MP99 on 01/05/2018 08:28 AM


If they inject directly into heliocentric orbit the apoapsis will be significantly out of the ecliptic and very far away from Mars. This might not be a bad thing, but it's not really a Mars-like orbit.
Yes expect direct injection - am very interested in how much C3 a kerolox cluster vehicle can impart.

This mission seems to be launching a very light payload to a C3 far short of what should be possible. (Unless there's a lot of ballast?)

Does this really demonstrate FH's capabilities?

Yes, it demostrates capacity to:
1) clear the pad and reach orbit with the 27 1st stage engines
2) two boosters to simultaneously RTLS
3) center core to do deorbit burn and land on barge from much higher velocity than what was has been done during F9 missions. Actually this light >C3 payload maximizes the velocity for the center core, making it harder than for average FH (military satellite) payload mission.
4) guidance system to push payloads into precise trajectories going very far away


The fact that is does not use all the fuel/lifting capacity available does not matter. If there would be something wrong decreasing the capacity, they would notice it because their tanks would ocntain less fuel than what they have calculated.
Yeah, I get that F9US is a mature system and they can gauge remaining prop loads from the acceleration profile, and therefore guesstimate the unused performance.

Nevertheless, it is disappointing that they aren't burning to depletion., with the Tesla doing a flyby of mars instead.

I suspect that the Tesla can't cope with the G levels. Don't want things breaking off and shifting the CoG.

But, still: boo!

Cheers, Martin

Sent from my GT-N5120 using Tapatalk

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Pete on 01/05/2018 09:53 AM
This mission seems to be launching a very light payload to a C3 far short of what should be possible. (Unless there's a lot of ballast?)

Does this really demonstrate FH's capabilities?

Cheers, Martin


The purpose of this Falcon 9 Heavy launch is NOT to show the FH's improved lifting capabilities, but simply its ability to actually fly in a controlled and safe way.

IF all the bits work as planned, SpaceX knows quite accurately what the resultant performance will be.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: jee_c2 on 01/05/2018 10:08 AM
Hi,

do we know about the FAA license for the flight?
It is not listed here: https://www.faa.gov/data_research/commercial_space_data/licenses/ (https://www.faa.gov/data_research/commercial_space_data/licenses/)
Probably it is shown some other way, since a lot of planned flights are not listed here.
Thanks.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: john smith 19 on 01/05/2018 10:13 AM
Yes, it demostrates capability to:
1) clear the pad and reach orbit with the 27 1st stage engines
2) two boosters to simultaneously RTLS
3) center core to do deorbit burn and land on barge from much higher velocity than what was has been done during F9 missions. Actually this light >C3 payload maximizes the velocity for the center core, making it harder than for average FH (military satellite) payload mission.
4) guidance system to push payloads into precise trajectories going very far away


The fact that is does not use all the fuel/lifting capacity available does not matter. If there would be something wrong decreasing the capacity, they would notice it because their tanks would ocntain less fuel than what they have calculated.
For future FH missions (and the ultimate goal of Mars) those are much more interesting capabilities that just sending an old car to Mars.
1) & 2) look to be in the "Shouldn't be an issue, but..." category. The shear number of things happening together, especially interaction effects. In principal a lot of this stuff should have been worked out well in advance, but of course there is always the possibility of those  "Unknown unknowns" lurking.
3) Looks like the closest SX will come to being able to study the damage level of a returning US short of returning an upper stage. Expanding the knowledgebase prior to BFS heatshield design.
4) is good for any payloads. The tighter the repeatable orbital parameters the smaller the margins  you can use, leaving either a bigger payload or more spare propellant for other purposes. But yes Mars is
potentially 500 000x further away than LEO and still close to 6000x further out than GEO. Unless you're JPL this is not something you're doing routinely, or planning to, unless  you're SX.

Compared to acquiring these capabilities (and their effects on SX competitiveness for NSS launches) putting a Tesla in the vicinity of Mars is (literally) a side show.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: octavo on 01/05/2018 10:38 AM
Is the roadster mounted at the angle it is to keep the 2nd stage thrust vector through the CoG?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: vanoord on 01/05/2018 11:19 AM
Is the roadster mounted at the angle it is to keep the 2nd stage thrust vector through the CoG?

IIRC it's slightly too large to fit inside the fairing flat - the angle reduces the effective 'length' so it will fit.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: OneSpeed on 01/05/2018 11:36 AM
My guess would be about 6:00 PM (18:00) local time.  My reasoning is this:  injection is most efficient when exactly the opposite of the intended target.  To get maximum throw, they need the target to be tangent to the Earth's orbit.   This puts the opposite point at about 18:00 local time.   This is only true for direct injection - with a parking orbit, the earth departure burn needs to happen about 18:00 local time (in the probe's time zone) but the launch can be anytime.

Shouldn't that be midnight local time? For a Hohmann transfer, apoapsis and periapsis are on opposite sides of the sun, and the tangent to Earth is on the far side from the Sun.

You want to leave Earth at midnight local time, but the way to do that is to burn at 18:00 local time, then the Earth bends the trajectory around 1/4 turn.   To see this, imagine a super long and skinny orbit around the Earth with a 40,000,000 km apogee.  If the long axis of this orbit is tangent to the Earth's orbit, then the perigee is at the trailing edge of Earth, or about 18:00 local time.  Since firing at perigee is the most efficient time, that's where the injection should be.

Yes, you do want to leave Earth orbit at midnight. But for direct injection, the burn only takes about 10 minutes, so launch should be at about 11:50pm local time.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rpapo on 01/05/2018 11:53 AM
Yes, you do want to leave Earth orbit at midnight. But for direct injection, the burn only takes about 10 minutes, so launch should be at about 11:50pm local time.
Rather than having a night launch as the first attempt, wouldn't it be better to launch in daylight (preferably just before sunset for the best lighting of the ascent), and then do the Hohmann transfer orbit injection burn once everything is (hopefully) safe in orbit?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Heinrich on 01/05/2018 12:15 PM

Yes, you do want to leave Earth orbit at midnight. But for direct injection, the burn only takes about 10 minutes, so launch should be at about 11:50pm local time.

You're forgetting the fact that the rocket travels downrange in those ten minutes. ..
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: kevinof on 01/05/2018 12:25 PM
Yes. I can't see them launching the first FH in the dark, just to make a preferred orbit timing. The launch is the primary goal, where the roadster ends up is very secondary.

Yes, you do want to leave Earth orbit at midnight. But for direct injection, the burn only takes about 10 minutes, so launch should be at about 11:50pm local time.
Rather than having a night launch as the first attempt, wouldn't it be better to launch in daylight (preferably just before sunset for the best lighting of the ascent), and then do the Hohmann transfer orbit injection burn once everything is (hopefully) safe in orbit?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: OneSpeed on 01/05/2018 12:37 PM
Yes, you do want to leave Earth orbit at midnight. But for direct injection, the burn only takes about 10 minutes, so launch should be at about 11:50pm local time.
Rather than having a night launch as the first attempt, wouldn't it be better to launch in daylight (preferably just before sunset for the best lighting of the ascent), and then do the Hohmann transfer orbit injection burn once everything is (hopefully) safe in orbit?

It depends how lofted the demo mission profile will be. If the core stage ASDS landing is only 342 kms downrange as indicated here: https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=current&application_seq=80084&RequestTimeout=1000 , then my money is on direct injection. Conversely, an optimal FH burn to LEO would land the core stage much further downrange, and imply a separate TMI burn, as you suggest.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 01/05/2018 02:05 PM
If they inject directly into heliocentric orbit the apoapsis will be significantly out of the ecliptic and very far away from Mars. This might not be a bad thing, but it's not really a Mars-like orbit.

All GTO launches coast for about 1/4 orbit and relight over the equator. SpaceX obviously has the necessary tracking assets to do this, and even streams live video from the S2 over Africa, well out of range of the Florida stations. I see no reason why the TMI burn wouldn't also occur over Africa.

I imagine the equator is of little use for this launch, because the Earth is tilted a good 23ish degrees from the plane of the ecliptic.

(http://1.bp.blogspot.com/-fI0BeZ44DeU/ToJxftzfnkI/AAAAAAAAAXY/DkDDdwLHpbg/s1600/earth+lines.gif)

As such, I assume SpaceX won't do much more than wait until the Earth rotates the rocket near the plane of the ecliptic and then just go for direct injection. Could probably zero out that 4 degree difference pretty easily if they really wanted to; but I too think that they'll deliberately send the stage slightly off-plane so they can guarantee that it will never hit Mars.

If they do need to go to an intermediate parking orbit, I think 23.5 degree is what they'd need to aim for.

As I understand it, to launch into the ecliptic in the direction of the Earth’s motion the escape burn has to happen over the intersection of the terminator and the ecliptic. At the Winter Solstice, with the South Pole tipped directly at the Sun, that would be the Equator. As time goes by it slides north, reaching 23.5 deg, the Tropic is Cancer, at the Vernal Equinox. The direction of travel to that antipode doesn't matter .
The point on the terminator is adjusted to change the inclination of the orbit with some small loss in velocity and aphelion.
Adjusting in that and longitude changes the location of the aphelion relative to the ecliptic and the orbit of Mars.
SpaceX can use this to prevent the Roadster intersecting Mars, or to get close if Musk wanted to start colonizing Mars on a microscopic scale. 😉
All of this can be found in any orbital mechanics textbook but they always supposed that the goal is to maximize payload and minimize the required velocity. This is not the case for Falcon Heavy throwing a little Roadster without a precise target.


Edit: That puts the launch near solar noon. Daytime to the extreme.
Edit 2: In the diagram above, assuming launch is soon, the Earth is viewed from forward along the Earth’s velocity and the antipode, the place for the burn, is opposite the shiny spot on the Equator.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/05/2018 02:38 PM
If they inject directly into heliocentric orbit the apoapsis will be significantly out of the ecliptic and very far away from Mars. This might not be a bad thing, but it's not really a Mars-like orbit.

All GTO launches coast for about 1/4 orbit and relight over the equator. SpaceX obviously has the necessary tracking assets to do this, and even streams live video from the S2 over Africa, well out of range of the Florida stations. I see no reason why the TMI burn wouldn't also occur over Africa.

I imagine the equator is of little use for this launch, because the Earth is tilted a good 23ish degrees from the plane of the ecliptic.

(http://1.bp.blogspot.com/-fI0BeZ44DeU/ToJxftzfnkI/AAAAAAAAAXY/DkDDdwLHpbg/s1600/earth+lines.gif)

As such, I assume SpaceX won't do much more than wait until the Earth rotates the rocket near the plane of the ecliptic and then just go for direct injection. Could probably zero out that 4 degree difference pretty easily if they really wanted to; but I too think that they'll deliberately send the stage slightly off-plane so they can guarantee that it will never hit Mars.

If they do need to go to an intermediate parking orbit, I think 23.5 degree is what they'd need to aim for.

As I understand it, to launch into the ecliptic in the direction of the Earth’s motion the escape burn has to happen over the intersection of the terminator and the ecliptic. At the Winter Solstice, with the South Pole tipped directly at the Sun, that would be the Equator. As time goes by it slides north, reaching 23.5 deg, the Tropic is Cancer, at the Vernal Equinox. The direction of travel to that antipode doesn't matter .
The point on the terminator is adjusted to change the inclination of the orbit with some small loss in velocity and aphelion.
Adjusting in that and longitude changes the location of the aphelion relative to the ecliptic and the orbit of Mars.
SpaceX can use this to prevent the Roadster intersecting Mars, or to get close if Musk wanted to start colonizing Mars on a microscopic scale. 😉
All of this can be found in any orbital mechanics textbook but they always supposed that the goal is to maximize payload and minimize the required velocity. This is not the case for Falcon Heavy throwing a little Roadster without a precise target.


Edit: That puts the launch near solar noon. Daytime to the extreme.
Edit 2: In the diagram above, assuming launch is soon, the Earth is viewed from forward along the Earth’s velocity and the antipode, the place for the burn, is opposite the shiny spot on the Equator.

I think that graphic is the view from the Sun at the Autumnal Equinox, with the "shiny spot" being a representation of the Sun's specular reflection.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 01/05/2018 02:57 PM
I think that graphic is the view from the Sun at the Autumnal Equinox, with the "shiny spot" being a representation of the Sun's specular reflection.

The image is generic and always true.
The viewpoint changes with the seasons.
It was the view back along the Eart’s orbit two weeks ago at the the Solstice.
Today it is swung around ~15 degrees.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/05/2018 03:26 PM
I think that graphic is the view from the Sun at the Autumnal Equinox, with the "shiny spot" being a representation of the Sun's specular reflection.

The image is generic and always true.
The viewpoint changes with the seasons.
It was the view back along the Eart’s orbit two weeks ago at the the Solstice.
Today it is swung around ~15 degrees.

Indeed. But you will only see a fully-lit disk when looking from the direction of the Sun.

At any rate, why would the departure burn be at the terminator? At that point, the vehicle will be flying directly away from (or towards) the Sun.

Optimal Earth departure into a heliocentric Hohmann transfer towards an outer planet requires that the LEO velocity vector be aligned as closely as possible with the direction of the Hohmann orbit at periapsis. This Hohmann orbit is tangent with the the Earth's orbit, meaning the LEO orbit direction needs to be as close as possible to the Earth's heliocentric orbit direction which only happens at local midnight.

That is opposite the "shiny spot", as you mentioned, assuming the view is from the direction of the Sun. But if the view is from the direction of the Earth's travel then it would be on the left side of the disk and coming out of the page towards the viewer. Either way it's at local midnight.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Nomadd on 01/05/2018 03:55 PM


The image is generic and always true.
The viewpoint changes with the seasons.
It was the view back along the Eart’s orbit two weeks ago at the the Solstice.
Today it is swung around ~15 degrees.
That view is obviously at the equinox.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: LouScheffer on 01/05/2018 04:03 PM

At any rate, why would the departure burn be at the terminator? At that point, the vehicle will be flying directly away from (or towards) the Sun.

Optimal Earth departure into a heliocentric Hohmann transfer towards an outer planet requires that the LEO velocity vector be aligned as closely as possible with the direction of the Hohmann orbit at periapsis. This Hohmann orbit is tangent with the the Earth's orbit, meaning the LEO orbit direction needs to be as close as possible to the Earth's heliocentric orbit direction which only happens at local midnight.

The problem is that the Earth's gravity turns the direction of the vector after the burn.  If you add infinite velocity, then the Earth's gravity has no impact, and it's best to burn at midnight.   But in practice, you are just above Earth escape, and you get a bend of almost 90 degrees.   Imagine a really high apogee orbit as shown below, where the bend is exactly 90 degrees.   The dot shows where you need to burn to go from the circular parking orbit to the high apogee orbit.  This is the same place the direct injection needs to terminate.
(http://lscheffer.com/images/BurnAt1800.png)
Now as you add velocity above Earth escape, the optimum point rotates around, until with infinite added velocity it's at midnght.  But a Mars apogee orbit is very much closer to earth escape than infinity, so the burn position is close to that shown.  On the other hand, as another poster pointed out, the launch takes a finite amount of time, which rotates the launch point further clockwise.  Overall you should launch much closer to 1800 than midnight.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 01/05/2018 04:50 PM
Please also keep in mind two things:

The planets aren't always in the ecliptic (Mars and Jupiter are in Libra, both above the ecliptic) - see image.

The planets are non-coplanar, and if you are actually "shooting" for  intersecting Mars orbit, one has to  target in (at least) the Earth Sun N body case where it will be (for orbital entry or landing, you also need your entry vector into the Mars Sun N body case correct too). All this adds up to launch azimuth and  inclination of ascent (gravity losses), and yes if you want to use props wisely absent the need to keep costs/margin/tracking requirement minimums, you'll want to handle this at the equator.

Oh and FH is a three stage LV, so optimum use of the core you'd also like to burn considerably downrange as well in the helioicentric frame, trading off the Earth/Sun (and often Moon) frame for the best choice of momentum transfer.

(Given the payload size, and the nature of this somewhat obtuse need to be "Mars-like" on a test launch, much of this is overkill (there's no kill like overkill).)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 01/05/2018 05:09 PM

At any rate, why would the departure burn be at the terminator? At that point, the vehicle will be flying directly away from (or towards) the Sun.

Optimal Earth departure into a heliocentric Hohmann transfer towards an outer planet requires that the LEO velocity vector be aligned as closely as possible with the direction of the Hohmann orbit at periapsis. This Hohmann orbit is tangent with the the Earth's orbit, meaning the LEO orbit direction needs to be as close as possible to the Earth's heliocentric orbit direction which only happens at local midnight.

The problem is that the Earth's gravity turns the direction of the vector after the burn.  If you add infinite velocity, then the Earth's gravity has no impact, and it's best to burn at midnight.   But in practice, you are just above Earth escape, and you get a bend of almost 90 degrees.   Imagine a really high apogee orbit as shown below, where the bend is exactly 90 degrees.   The dot shows where you need to burn to go from the circular parking orbit to the high apogee orbit.  This is the same place the direct injection needs to terminate.
(http://lscheffer.com/images/BurnAt1800.png)
Now as you add velocity above Earth escape, the optimum point rotates around, until with infinite added velocity it's at midnght.  But a Mars apogee orbit is very much closer to earth escape than infinity, so the burn position is close to that shown.  On the other hand, as another poster pointed out, the launch takes a finite amount of time, which rotates the launch point further clockwise.  Overall you should launch much closer to 1800 than midnight.

That's a great illustration. So it seems like a late afternoon launch would be close to perfect. (It also allows them to launch during daylight hours, which is probably an internal requirement for collecting the maximum visual data on the launch)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/05/2018 05:10 PM

At any rate, why would the departure burn be at the terminator? At that point, the vehicle will be flying directly away from (or towards) the Sun.

Optimal Earth departure into a heliocentric Hohmann transfer towards an outer planet requires that the LEO velocity vector be aligned as closely as possible with the direction of the Hohmann orbit at periapsis. This Hohmann orbit is tangent with the the Earth's orbit, meaning the LEO orbit direction needs to be as close as possible to the Earth's heliocentric orbit direction which only happens at local midnight.

The problem is that the Earth's gravity turns the direction of the vector after the burn.  If you add infinite velocity, then the Earth's gravity has no impact, and it's best to burn at midnight.   But in practice, you are just above Earth escape, and you get a bend of almost 90 degrees.   Imagine a really high apogee orbit as shown below, where the bend is exactly 90 degrees.   The dot shows where you need to burn to go from the circular parking orbit to the high apogee orbit.  This is the same place the direct injection needs to terminate.
(http://lscheffer.com/images/BurnAt1800.png)
Now as you add velocity above Earth escape, the optimum point rotates around, until with infinite added velocity it's at midnght.  But a Mars apogee orbit is very much closer to earth escape than infinity, so the burn position is close to that shown.  On the other hand, as another poster pointed out, the launch takes a finite amount of time, which rotates the launch point further clockwise.  Overall you should launch much closer to 1800 than midnight.

Thanks, I wasn't accounting for that. That places the optimal injection burn time, but what about the launch time?

For a launch due east out of Canaveral to be as close to the ecliptic plane as possible at 1800 local time, the Earth would need to be near the vernal equinox (when the difference is about 4 degrees). But this launch will be much nearer the winter solstice, so SpaceX will either

1) launch N orbits early (when Canaveral is in plane) and coast to the injection burn - not sure what N values work here
2) launch direct to injection but inject out of the ecliptic or
3) launch ~1/4 orbit early (around 12:00 local) to near the equator and do a plane change to match the ecliptic, rather like a GTO launch
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Lars-J on 01/05/2018 05:13 PM
envy887, the Roadster is not going to Mars. It is going to be more of a Mars-like transfer orbit. (In fact, the less risk of impacting Mars, the better - Musk wants it to be up there for a billion years)

So there is no need to be so exact.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: octavo on 01/05/2018 05:40 PM
envy887, the Roadster is not going to Mars. It is going to be more of a Mars-like transfer orbit. (In fact, the less risk of impacting Mars, the better - Musk wants it to be up there for a billion years)

So there is no need to be so exact.
Unless you're also trying to demonstrate pinpoint long range trajectories maybe?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: RoboGoofers on 01/05/2018 06:00 PM

At any rate, why would the departure burn be at the terminator? At that point, the vehicle will be flying directly away from (or towards) the Sun.

Optimal Earth departure into a heliocentric Hohmann transfer towards an outer planet requires that the LEO velocity vector be aligned as closely as possible with the direction of the Hohmann orbit at periapsis. This Hohmann orbit is tangent with the the Earth's orbit, meaning the LEO orbit direction needs to be as close as possible to the Earth's heliocentric orbit direction which only happens at local midnight.

The problem is that the Earth's gravity turns the direction of the vector after the burn.  If you add infinite velocity, then the Earth's gravity has no impact, and it's best to burn at midnight.   But in practice, you are just above Earth escape, and you get a bend of almost 90 degrees.   Imagine a really high apogee orbit as shown below, where the bend is exactly 90 degrees.   The dot shows where you need to burn to go from the circular parking orbit to the high apogee orbit.  This is the same place the direct injection needs to terminate.
(http://lscheffer.com/images/BurnAt1800.png)
Now as you add velocity above Earth escape, the optimum point rotates around, until with infinite added velocity it's at midnght.  But a Mars apogee orbit is very much closer to earth escape than infinity, so the burn position is close to that shown.  On the other hand, as another poster pointed out, the launch takes a finite amount of time, which rotates the launch point further clockwise.  Overall you should launch much closer to 1800 than midnight.

That's a great illustration. So it seems like a late afternoon launch would be close to perfect. (It also allows them to launch during daylight hours, which is probably an internal requirement for collecting the maximum visual data on the launch)

It gets scoffed at a lot as just a video game, but Kerbal Space Program is an excellent teacher of basic orbital mechanics. Elementary school kids that play this "game" can teach this lesson to their apollo-era grandparents.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: hektor on 01/05/2018 06:14 PM
envy887, the Roadster is not going to Mars. It is going to be more of a Mars-like transfer orbit. (In fact, the less risk of impacting Mars, the better - Musk wants it to be up there for a billion years)

So there is no need to be so exact.
Unless you're also trying to demonstrate pinpoint long range trajectories maybe?

I have the impression that the later FH launches, the closer it is possible to bring it to Mars.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/05/2018 06:43 PM
envy887, the Roadster is not going to Mars. It is going to be more of a Mars-like transfer orbit. (In fact, the less risk of impacting Mars, the better - Musk wants it to be up there for a billion years)

So there is no need to be so exact.
Unless you're also trying to demonstrate pinpoint long range trajectories maybe?

No, since they can define a arbitrary target orbit and then measure how close to it they got.

The only reason to not do direct launch to injection is if they want to demonstrate LEO long coast, or want to get closer to Mars' orbital plane without the performance hit of a plane change. I don't think either of those are necessary: they demonstrated long LEO coast on NROL-76, they have plenty of performance for a plane change, and there's no particular reason to get in plane with Mars since that increases the chance of actually hitting Mars, which they don't want to do.

So direct launch to injection is likely, IMO. which puts launch time around 1800 local time in Florida, +/- an hour or so.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: kevinof on 01/05/2018 06:51 PM
Will there still be daylight at 18:00 local time? I really can't see them launching in the dark - my thinking is they will want cameras recording everything especially the separation events so sending this thing up in the dark would scupper that.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ZachS09 on 01/05/2018 06:55 PM
Will there still be daylight at 18:00 local time? I really can't see them launching in the dark - my thinking is they will want cameras recording everything especially the separation events so sending this thing up in the dark would scupper that.

Around the end of January 2018, sunset is approximately 6:00 PM Eastern Time (23:00 UTC). So, there's technically still daylight at that time.

Find the coordinates to LC-39A and enter them in the location box on this link.

https://www.esrl.noaa.gov/gmd/grad/solcalc/
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: clongton on 01/05/2018 07:07 PM
The problem is that the Earth's gravity turns the direction of the vector after the burn.  If you add infinite velocity, then the Earth's gravity has no impact, and it's best to burn at midnight.   But in practice, you are just above Earth escape, and you get a bend of almost 90 degrees.   Imagine a really high apogee orbit as shown below, where the bend is exactly 90 degrees.   The dot shows where you need to burn to go from the circular parking orbit to the high apogee orbit.  This is the same place the direct injection needs to terminate.

<snip> </snip>

Now as you add velocity above Earth escape, the optimum point rotates around, until with infinite added velocity it's at midnight.  But a Mars apogee orbit is very much closer to earth escape than infinity, so the burn position is close to that shown.  On the other hand, as another poster pointed out, the launch takes a finite amount of time, which rotates the launch point further clockwise.  Overall you should launch much closer to 1800 than midnight.


That's a great illustration, thanks.
I would add that without an additional phase burn that the trajectory would still not be in the solar plane of ecliptic, but rather will enter a heliocentric trajectory on the earth orbital inclination, and will thus not encounter Mars at all, demonstrating only that the Falcon Heavy has the ability to send a payload out as far as Mars.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: LouScheffer on 01/05/2018 07:10 PM
Will there still be daylight at 18:00 local time? I really can't see them launching in the dark - my thinking is they will want cameras recording everything especially the separation events so sending this thing up in the dark would scupper that.

I agree - I think a daylight launch, a short coast, then a terminator-ish Mars injection.  This also gives the possibility of a big launch window.

So I'd guess a window of 1000 to 1400 local, a coast (10--30 minutes) that depends on the time of launch, the an injection at about 1800 local time for the payload.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rakaydos on 01/05/2018 07:11 PM
Is the roadster mounted at the angle it is to keep the 2nd stage thrust vector through the CoG?

I suspect it is to aid Horizontal Integration. The tesla may be able to hang vertically from it's jack points when the fairing is sideways, but why risk it?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/05/2018 07:11 PM
The problem is that the Earth's gravity turns the direction of the vector after the burn.  If you add infinite velocity, then the Earth's gravity has no impact, and it's best to burn at midnight.   But in practice, you are just above Earth escape, and you get a bend of almost 90 degrees.   Imagine a really high apogee orbit as shown below, where the bend is exactly 90 degrees.   The dot shows where you need to burn to go from the circular parking orbit to the high apogee orbit.  This is the same place the direct injection needs to terminate.

<snip> </snip>

Now as you add velocity above Earth escape, the optimum point rotates around, until with infinite added velocity it's at midnight.  But a Mars apogee orbit is very much closer to earth escape than infinity, so the burn position is close to that shown.  On the other hand, as another poster pointed out, the launch takes a finite amount of time, which rotates the launch point further clockwise.  Overall you should launch much closer to 1800 than midnight.


That's a great illustration, thanks.
I would add that without an additional phase burn that the trajectory would still not be in the solar plane of ecliptic, but rather will enter a heliocentric trajectory on the earth orbital inclination, and will thus not encounter Mars at all, demonstrating only that the Falcon Heavy has the ability to send a payload out as far as Mars.

They can also demonstrate orbit injection accuracy relative to a predefined target orbit. There's no need to define the target orbit relative to Mars.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Space Ghost 1962 on 01/05/2018 07:15 PM
Also, this is a test launch.

You want good illumination, good weather / visibility so that you can see any deviation.

Also, you want to track in the eastern range (especially to F9US engine start), so not so much downrange with the core as you otherwise might for such a light payload.

It's not about the payload on this flight, its about the flight data. 
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rsdavis9 on 01/05/2018 07:43 PM
I think people (or me) are missing the 28deg of Cape Canaveral. At the winter solstice Cape Canaveral is just about exactly on the ecliptic at midnight. (28-23.5=4.5). If you boost straight east you get the maximum assist from the earth's rotation in the desired direction. So the following changes this position:
1. not at solstice.
2. not instantaneous delta-v application
3. not infinite velocity so gravity curves the trajectory

So I guess somewhere around 1800-2400 lies the maximum ecliptic delta-v vector addition.
So given any season to launch in the ecliptic. What season gives the most delta-v in the earths orbit vector?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: mme on 01/05/2018 07:53 PM
Also, this is a test launch.

You want good illumination, good weather / visibility so that you can see any deviation.

Also, you want to track in the eastern range (especially to F9US engine start), so not so much downrange with the core as you otherwise might for such a light payload.

It's not about the payload on this flight, its about the flight data.
This. A million times this.

This mission is not targeting Mars, it's not about maximizing delta-v and it's not about the upper-stage doing something new or different. It's about proving the FH works as expected and collecting the maximum amount of data to verify that and/or be able to determine what went wrong.

Also the last thing they want is to actually impact Mars.

My money is on a mission that has a daylight launch with a long launch window without the US having a longer than already proven linger time.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: john smith 19 on 01/05/2018 09:05 PM
I think that graphic is the view from the Sun at the Autumnal Equinox, with the "shiny spot" being a representation of the Sun's specular reflection.

The image is generic and always true.
The viewpoint changes with the seasons.
It was the view back along the Eart’s orbit two weeks ago at the the Solstice.
Today it is swung around ~15 degrees.
I never really understood why the Tropics of Cancer and Capricorn were special.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: 1 on 01/05/2018 09:13 PM

At any rate, why would the departure burn be at the terminator? At that point, the vehicle will be flying directly away from (or towards) the Sun.

Optimal Earth departure into a heliocentric Hohmann transfer towards an outer planet requires that the LEO velocity vector be aligned as closely as possible with the direction of the Hohmann orbit at periapsis. This Hohmann orbit is tangent with the the Earth's orbit, meaning the LEO orbit direction needs to be as close as possible to the Earth's heliocentric orbit direction which only happens at local midnight.

The problem is that the Earth's gravity turns the direction of the vector after the burn.  If you add infinite velocity, then the Earth's gravity has no impact, and it's best to burn at midnight.   But in practice, you are just above Earth escape, and you get a bend of almost 90 degrees.   Imagine a really high apogee orbit as shown below, where the bend is exactly 90 degrees.   The dot shows where you need to burn to go from the circular parking orbit to the high apogee orbit.  This is the same place the direct injection needs to terminate.
(http://lscheffer.com/images/BurnAt1800.png)
Now as you add velocity above Earth escape, the optimum point rotates around, until with infinite added velocity it's at midnght.  But a Mars apogee orbit is very much closer to earth escape than infinity, so the burn position is close to that shown.  On the other hand, as another poster pointed out, the launch takes a finite amount of time, which rotates the launch point further clockwise.  Overall you should launch much closer to 1800 than midnight.

But that's the thing. As others mentioned, we don't actually have a target to reach since this is a vehicle test. We're just going for a generic heliocentric orbit where aphelion reaches out towards Mars. I don't think we want to go 'left'. We want to go 'down'. And if Space Ghost's thoughts about keeping the launch over Florida range assets as long as possible are plausible, we might not even want to launch east but rather do something like launch at 6 in the morning going more or less straight up. Energetically efficient? Probably not, but who cares as long as the vehicle works properly?

Edit:
Also, to some others, yes, that first image I dug up was just a generic image; not intended to show where the Earth is today. My post subsequent to that first one explained my assumptions on where the Earth is now.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Comga on 01/05/2018 10:08 PM

At any rate, why would the departure burn be at the terminator? At that point, the vehicle will be flying directly away from (or towards) the Sun.

Optimal Earth departure into a heliocentric Hohmann transfer towards an outer planet requires that the LEO velocity vector be aligned as closely as possible with the direction of the Hohmann orbit at periapsis. This Hohmann orbit is tangent with the the Earth's orbit, meaning the LEO orbit direction needs to be as close as possible to the Earth's heliocentric orbit direction which only happens at local midnight.

The problem is that the Earth's gravity turns the direction of the vector after the burn.  If you add infinite velocity, then the Earth's gravity has no impact, and it's best to burn at midnight.   But in practice, you are just above Earth escape, and you get a bend of almost 90 degrees.   Imagine a really high apogee orbit as shown below, where the bend is exactly 90 degrees.   The dot shows where you need to burn to go from the circular parking orbit to the high apogee orbit.  This is the same place the direct injection needs to terminate.
(http://lscheffer.com/images/BurnAt1800.png)
Now as you add velocity above Earth escape, the optimum point rotates around, until with infinite added velocity it's at midnght.  But a Mars apogee orbit is very much closer to earth escape than infinity, so the burn position is close to that shown.  On the other hand, as another poster pointed out, the launch takes a finite amount of time, which rotates the launch point further clockwise.  Overall you should launch much closer to 1800 than midnight.

Thanks, I wasn't accounting for that. That places the optimal injection burn time, but what about the launch time?

For a launch due east out of Canaveral to be as close to the ecliptic plane as possible at 1800 local time, the Earth would need to be near the vernal equinox (when the difference is about 4 degrees). But this launch will be much nearer the winter solstice, so SpaceX will either

1) launch N orbits early (when Canaveral is in plane) and coast to the injection burn - not sure what N values work here
2) launch direct to injection but inject out of the ecliptic or
3) launch ~1/4 orbit early (around 12:00 local) to near the equator and do a plane change to match the ecliptic, rather like a GTO launch

We'll have what's behind door number three.
(except no plane change is needed.  That's only relative to the Earth, which on the scale of solar orbits is small.)
If you want the orbit to cross the equator and terminator you launch due east at solar noon.
After a quarter orbit the spacecraft is at the that point, the equator and terminator.
That makes for the most efficient launch "forward" with respect to the Earth's orbit around the Sun.

Note that with a light payload, SpaceX doesn't have to be maximally efficient, so they can do this slightly differently.
Also, as pointed out by Space Ghost and myself, there is the issue of the inclination of the orbit and the location of the perihelion relative to the orbit of Mars.  To avoid contact, or gravitational perturbation which will eventually be chaotic (unpredictable with available precision of launch injection) SpaceX may further modify the launch timing and aiming.

edit: Launching "N orbits early" requires a second stage operational lifetime that has not been demonstrated to date.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: the_other_Doug on 01/06/2018 12:19 AM
My guess would be about 6:00 PM (18:00) local time.  My reasoning is this:  injection is most efficient when exactly the opposite of the intended target.  To get maximum throw, they need the target to be tangent to the Earth's orbit.   This puts the opposite point at about 18:00 local time.   This is only true for direct injection - with a parking orbit, the earth departure burn needs to happen about 18:00 local time (in the probe's time zone) but the launch can be anytime.

Shouldn't that be midnight local time? For a Hohmann transfer, apoapsis and periapsis are on opposite sides of the sun, and the tangent to Earth is on the far side from the Sun.

You want to leave Earth at midnight local time, but the way to do that is to burn at 18:00 local time, then the Earth bends the trajectory around 1/4 turn.   To see this, imagine a super long and skinny orbit around the Earth with a 40,000,000 km apogee.  If the long axis of this orbit is tangent to the Earth's orbit, then the perigee is at the trailing edge of Earth, or about 18:00 local time.  Since firing at perigee is the most efficient time, that's where the injection should be.

Hopefully, this point hasn't been made yet.  Dangers of responding two pages up from the end of the thread...

I think SpaceX will launch during daylight.  This is first and foremost a demonstration of the launcher.  They will want the best overall visibility of the rocket for the tracking cameras (in case of an RUD and also to gather the most info they can from the flight), and you just don't get that with night launches.  With a night launch, the light of the exhaust completely overwhelms detailed imagery of what the rocket itself is doing.  Not a good idea on a first flight.

All they want to demonstrate is that they can push a payload out to the "neighborhood" of Mars.  It doesn't have to be exactly in Mars' orbital inclination.  Remember, no one at this point needs to demonstrate that FH can target a payload actually to the planet Mars, as it seems it will never be called upon to do so.  Just getting the payload out as far away from the Sun as Mars in a heliocentric orbit is all SpaceX really has to worry about.

For that, you can launch pretty much any time of day you like, as far as inclination to the ecliptic is concerned.  And I imagine you could launch pretty much any time past local noon to get a direct injection into a solar orbit with an aphelion of one and a half AU.

So, as I say, since there is no reason to actually target the planet Mars with this launch, I can't at all imagine they will launch the FH first check-flight at night, when they can't see the dynamics of the elements of the rocket, except insofar as they impact the plumes.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cscott on 01/06/2018 01:15 AM
Just to throw a wrench in the orbit discussion: https://physics.stackexchange.com/questions/123029/why-is-there-a-gap-in-porkchop-plots and http://hopsblog-hop.blogspot.com/2013/01/deboning-porkchop-plot.html

See the porkchop plot below (from http://forum.nasaspaceflight.com/index.php?topic=42705.msg1765780.msg#1765780 ): we're in the middle of the "ridge" between type 1 and type 2 orbits this month.

Unless SpaceX is going to do a midpoint burn of the S2 (ie after approx 100 days,  significantly longer than the longest S2 loiter to date which is... I think, almost 31 minutes ---

Anyway, unless it is going to do that, as the "deboning the pork chop" post explains, the great circle route to Mars actually takes you "up" in a polar-ish orbit over the plane of the ecliptic.

 If we're not going to hit Mars anyway, there's really no reason to try to aim for 0-degree inclination to the ecliptic.
(https://uploads.tapatalk-cdn.com/20180106/e62aa4d5296971827fe02dfda0046890.jpg)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: TorenAltair on 01/07/2018 12:08 PM
I really need some vacation.. What a dream last night.. Falcon Heavy (unfuelled) tipped over and crashed onto the pad. I thought .. "oh..will the Tesla survive this one?". As the fairing hit the ground, it exploded.. poor Tesla.  :o
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Mike_1179 on 01/07/2018 12:42 PM

I never really understood why the Tropics of Cancer and Capricorn were special.


On the day of the equinox at the equator at noon, a vertical pole casts no shadow and you can see to the bottom of your well. Every day after that equinox, the sun will be off-vertical more and more at noon on the equator and will cast a longer and longer shadow each day until the solstice, where shadows would then get shorter until the next equinox.

If you’re a little above the equator, the day the sun casts no shadow at noon is a few days after the equinox, this day gets further and further from the equinox the more north or south you go (depending on the season). On the summer solstice, the place where the sun casts no shadow is along the Tropic of Cancer. It is the most northerly circle of latitude on Earth at which the Sun can be directly overhead. The same happens along the Tropic of Capricorn on the day of the winter solstice.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: crandles57 on 01/07/2018 01:42 PM
Could it be possible to use Mars' gravitational pull to partially circularise the orbit so that orbit remains higher than Earth's orbit? Just wondering if this might be a reason to aim for apoapsis somewhere near Mars L1 point so it gets pulled up and round the sun a bit more by Mars to keep it away from Earth.

(For that matter, what is speed at apoapsis if at distance of Mars L1 point from sun, and how does that compare with Mars L1 orbit speed? Seems like this could be a route to Mars orbit that requires less energy?)

Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: rsdavis9 on 01/07/2018 02:26 PM

I never really understood why the Tropics of Cancer and Capricorn were special.


On the day of the equinox at the equator at noon, a vertical pole casts no shadow and you can see to the bottom of your well. Every day after that equinox, the sun will be off-vertical more and more at noon on the equator and will cast a longer and longer shadow each day until the solstice, where shadows would then get shorter until the next equinox.

If you’re a little above the equator, the day the sun casts no shadow at noon is a few days after the equinox, this day gets further and further from the equinox the more north or south you go (depending on the season). On the summer solstice, the place where the sun casts no shadow is along the Tropic of Cancer. It is the most northerly circle of latitude on Earth at which the Sun can be directly overhead. The same happens along the Tropic of Capricorn on the day of the winter solstice.

Cancer and Capricorn refer to the signs of the zodiac or constellations(I think signs) that the sun is in at the solstices.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Perchlorate on 01/07/2018 04:05 PM
"If you’re a little above the equator, the day the sun casts no shadow at noon is a few days after the equinox, this day gets further and further from the equinox the more north or south you go (depending on the season). On the summer solstice, the place where the sun casts no shadow is along the Tropic of Cancer. It is the most northerly circle of latitude on Earth at which the Sun can be directly overhead. The same happens along the Tropic of Capricorn on the day of the winter solstice."

Not inaccurate.  Given that the tropic lines are where the sun is directly overhead at solstice, would it be more appropriate to say, "The same happens along the Tropic of Capricorn on the day of the summer solstice in the Southern Hemisphere."?

[...and I have this eerie feeling of a mod lurking, ready to rein in this excursion into tangential relevance.]
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: 321_SNI on 01/07/2018 05:49 PM
I really need some vacation.. What a dream last night.. Falcon Heavy (unfuelled) tipped over and crashed onto the pad. I thought .. "oh..will the Tesla survive this one?". As the fairing hit the ground, it exploded.. poor Tesla.  :o

Her hee, TorenAltair, do anything to get rid of such horribly ridiculous (or,well, just plain horrible!) dreams.  Don't need ANY energy like that!!  So tonight, after the Zuma launch, think of the beautiful, fluffy white engine plumes sweetly lifting it into flight!  Or...just try some warm milk before bed!!  **But more seriously, do you, (or does anyone) know if the great machine is on the pad yet?  (The great FH, that is).
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: TorenAltair on 01/07/2018 07:18 PM
@321_SNI

As far as I know no, it is not on the pad. I assume they are all busy now to get that Zuma thing finally thrown to orbit.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 01/07/2018 07:28 PM
I really need some vacation.. What a dream last night.. Falcon Heavy (unfuelled) tipped over and crashed onto the pad. I thought .. "oh..will the Tesla survive this one?". As the fairing hit the ground, it exploded.. poor Tesla.  :o

Her hee, TorenAltair, do anything to get rid of such horribly ridiculous (or,well, just plain horrible!) dreams.  Don't need ANY energy like that!!  So tonight, after the Zuma launch, think of the beautiful, fluffy white engine plumes sweetly lifting it into flight!  Or...just try some warm milk before bed!!  **But more seriously, do you, (or does anyone) know if the great machine is on the pad yet?  (The great FH, that is).
Roll out appears next week if you read SpaceX and Elon tweets carefully.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Yeknom-Ecaps on 01/07/2018 07:48 PM
https://twitter.com/elonmusk/status/949075475036487680

@elonmusk
Falcon Heavy goes vertical

Video attached

Is Falcon Heavy back on the pad for the second time or was this video a repeat of the December rising on pad 39A?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: IanThePineapple on 01/07/2018 08:14 PM
https://twitter.com/elonmusk/status/949075475036487680

@elonmusk
Falcon Heavy goes vertical

Video attached

Is Falcon Heavy back on the pad for the second time or was this video a repeat of the December rising on pad 39A?

Probably from the December fit check, we would know if they did another
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Jdeshetler on 01/08/2018 02:39 AM
SpaceX FH Demo - Simulation of 2 boosters returning side by side in daytime thru long range tracking camera.

https://www.youtube.com/watch?v=qBHVnrJkCzw
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: meekGee on 01/08/2018 02:58 AM
SpaceX FH Demo - Simulation of 2 boosters returning side by side in daytime thru long range tracking camera.

https://www.youtube.com/watch?v=qBHVnrJkCzw
Haha... I knew what this would be even before clicking, but then watched it anyway, and with a smile...

Guilty as charged :)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: cuddihy on 01/08/2018 04:58 AM
They’re too far apart unless the camera is in between LZ-1 & LZ-2. 🤓
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Mader Levap on 01/08/2018 12:05 PM
I have opposite impression: they are too close to each other.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Zed_Noir on 01/08/2018 12:33 PM
SpaceX FH Demo - Simulation of 2 boosters returning side by side in daytime thru long range tracking camera.

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

 ;D
So Saurion opens both eyes!
 ;D
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: maitri982 on 01/08/2018 02:23 PM
Anyone have expected launch dates on this yet?  There was some info on L2 about press pass dates...not sure if that is super duper top secret L2 stuff or not.  But the dates were different than prior expectations.

I am scheduling trip to FL around seeing this launch.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Ben the Space Brit on 01/08/2018 03:33 PM
SpaceNews has claimed that SpaceX is 'aiming' for late this month but that really doesn't have much weight. They've been occasionally 'aiming' for certain long-past targets several times in the last five or so years.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: gongora on 01/08/2018 03:36 PM
Planning a long distance trip for this one might require some quick reflexes.  You can't really count on a launch date until they conduct a good static fire, and after conducting a good static fire it might not be that long (a couple/few weeks) before the launch attempt.  Late January seems to be the current target, let's see what happens with testing in the next week.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: john smith 19 on 01/08/2018 03:37 PM
Launch date is end of January per Elon's instagram:

Quote
Falcon Heavy now vertical on the former Apollo 11 moon rocket launchpad. At 2500 tons of thrust, equal to 18 Boeing 747 aircraft at full throttle, it will be the most powerful rocket in the world by a factor of two. Excitement on launch day guaranteed, one way or another.

Hold-down test fire next week. Launch end of the month.
Even the hold down firing test will be pretty exciting. If27 engines are starting up with 0.2secs between each pair that alone will last close to 3 secs between the first and the last pair igniting.

Anyone. Any idea how long for a Merlin to get to steady state on these tests? will they have all of them run together, or will they shut down each pair as it reaches steady state?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: maitri982 on 01/08/2018 03:44 PM
Planning a long distance trip for this one might require some quick reflexes.  You can't really count on a launch date until they conduct a good static fire, and after conducting a good static fire it might not be that long (a couple/few weeks) before the launch attempt.  Late January seems to be the current target, let's see what happens with testing in the next week.

HA!!! No need to tell me.  I have tried twice to make launches (I live in Central PA...so not a short trip) and have been foiled over and over again.  Once by damn air force radar not working on what would have been beautiful day for launch.

I have scheduled trip for January 27-Feb 4th.  So may the launch gods have some mercy on me for once.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: oiorionsbelt on 01/08/2018 04:00 PM
Even the hold down firing test will be pretty exciting. If27 engines are starting up with 0.2secs between each pair that alone will last close to 3 secs between the first and the last pair igniting.
Is it certain that it's two engines at a time or two engines per core at a time?
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: oiorionsbelt on 01/08/2018 04:21 PM
To follow up on that question, what single engine will fire last? 27 and 9 are odd numbers.
 I assumed two per core with the center engine last.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 01/08/2018 04:34 PM
Even the hold down firing test will be pretty exciting. If27 engines are starting up with 0.2secs between each pair that alone will last close to 3 secs between the first and the last pair igniting.
Is it certain that it's two engines at a time or two engines per core at a time?

My understanding was one per core at a time, separated by 120ms. -- whole start about one second in duration, which we won't see except in slo-mo replay.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: wannamoonbase on 01/08/2018 05:09 PM
Even the hold down firing test will be pretty exciting. If27 engines are starting up with 0.2secs between each pair that alone will last close to 3 secs between the first and the last pair igniting.
Is it certain that it's two engines at a time or two engines per core at a time?

My understanding was one per core at a time, separated by 120ms. -- whole start about one second in duration, which we won't see except in slo-mo replay.

I recall it being pairs, 2 at a time, not 1 per core.

Edit: This is likely one, as well as staging are areas where they expect to tune (shorten) this once they get operational data and experience.

Edit-Edit: I like that SpaceX takes this approach.  NASA would spent billions and years modeling and testing.  SpaceX builds, assemblies, flies, gets paid, changes and fly again.  I really like this iterative approach, it has huge advantages for companies that have to pay their own way.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: BeamRider on 01/08/2018 05:30 PM
In reference to “launching straight up”, my understanding would be that this would NOT be a valid test of the vehicle. I am under the impression that when launching into orbit, LEO or GTO, the rocket stack experiences some non-trivial amount of aerodynamic “lift” force after it has assumed a horizontal trajectory. If this is true, launching straight up would not be a real test of the flight or booster sep characteristics.

If I am wrong I would appreciate correction. I think I heard EM make reference to the lift characteristics of a cylinder in this regard, and without some lift, I fail to see how the whole thing would not fall into a ballistic trajectory that terminated into the ocean. I appreciate that at exo-atmospheric altitudes there would be no aerodynamic forces, but at the altitudes up to and including side-booster sep, there could certainly be some.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Paul_G on 01/08/2018 05:42 PM
In reference to “launching straight up”, my understanding would be that this would NOT be a valid test of the vehicle. I am under the impression that when launching into orbit, LEO or GTO, the rocket stack experiences some non-trivial amount of aerodynamic “lift” force after it has assumed a horizontal trajectory. If this is true, launching straight up would not be a real test of the flight or booster sep characteristics.

If I am wrong I would appreciate correction. I think I heard EM make reference to the lift characteristics of a cylinder in this regard, and without some lift, I fail to see how the whole thing would not fall into a ballistic trajectory that terminated into the ocean. I appreciate that at exo-atmospheric altitudes there would be no aerodynamic forces, but at the altitudes up to and including side-booster sep, there could certainly be some.

Launching straight up will not get you to orbit. To go to orbit, you need to be moving very fast sideways, not so much up ways. On ascent, I don't think the lift of the stage (the cylinder) is a hugely meaningful part of the force needed to get into orbit, however on its way down, the lift does come in to play. My understanding is that SpaceX use the gridfins to position the stage so that it can use that lift to control where the stage comes down.

Paul
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Greg Hullender on 01/08/2018 05:46 PM
My impression was that there's enough lift that you have to take it into account, but not enough that it's worth trying to exploit. Someone probably has precise figures.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: ChrisGebhardt on 01/08/2018 06:42 PM
Cross posting here.  Last Friday I recorded a podcast with "Are We There Yet?".  We talked for an hour about the things coming up in 2018... including Falcon Heavy.

http://www.wmfe.org/exciting-year-ahead-for-space-exploration/82019
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: maitri982 on 01/08/2018 07:10 PM
Public source says NET the 29th:

 http://spaceflight101.com/calendar/ (http://spaceflight101.com/calendar/)
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Formica on 01/08/2018 07:25 PM
Pure speculation: might we see a second static fire? Much and more has been made of the complexity of lighting twenty seven engines. It would seem logical to analyze the first static fire and then, based on that, optimize and test again before launching.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: envy887 on 01/08/2018 07:52 PM
Pure speculation: might we see a second static fire? Much and more has been made of the complexity of lighting twenty seven engines. It would seem logical to analyze the first static fire and then, based on that, optimize and test again before launching.

Unless the first one goes perfectly, there will probably be a second.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: spacetraveler on 01/08/2018 07:59 PM
Launch date is end of January per Elon's instagram:

Quote
Falcon Heavy now vertical on the former Apollo 11 moon rocket launchpad. At 2500 tons of thrust, equal to 18 Boeing 747 aircraft at full throttle, it will be the most powerful rocket in the world by a factor of two. Excitement on launch day guaranteed, one way or another.

Hold-down test fire next week. Launch end of the month.
Even the hold down firing test will be pretty exciting. If27 engines are starting up with 0.2secs between each pair that alone will last close to 3 secs between the first and the last pair igniting.

Anyone. Any idea how long for a Merlin to get to steady state on these tests? will they have all of them run together, or will they shut down each pair as it reaches steady state?

I have to believe they want to get at least some data for all engines burning concurrently.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: FutureMartian97 on 01/08/2018 08:43 PM
If we see FH go back into the hanger we'll know the Zuma mishap was a vehicle issue.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: GeneBelcher on 01/08/2018 08:45 PM
And now on the pad!

Note: Payload is attached

Great view of the reaction frame as well.

https://twitter.com/SkeerRacing/status/950406990387433473

What's the red/pink ring around the boosters? Looks like something wrapped around and over the attach points of the grid fins.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: AncientU on 01/08/2018 08:46 PM
If we see FH go back into the hanger we'll know the Zuma mishap was a vehicle issue.

Don't get out ahead of the headlights... 'the Zuma mishap' is TBD, and FH is on the pad morning after launch.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: deruch on 01/08/2018 09:09 PM
And now on the pad!

Note: Payload is attached

Great view of the reaction frame as well.

https://twitter.com/SkeerRacing/status/950406990387433473

What's the red/ping ring around the boosters? Looks like something wrapped around and over the attach points of the grid fins.

"Plastic wrap" for moisture protection.  It is over the joints between stages. They do it for F9 launches too.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: Inoeth on 01/08/2018 09:39 PM
If we see FH go back into the hanger we'll know the Zuma mishap was a vehicle issue.

Perhaps you're right... I entirely missed the info about the possible Zuma issue... tho the fact that they rolled out the FH this morning many, many hours after the launch makes me guess that whatever issue Zuma is having, it's not SpaceX's fault.
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: moralec on 01/08/2018 09:50 PM

I never really understood why the Tropics of Cancer and Capricorn were special.


On the day of the equinox at the equator at noon, a vertical pole casts no shadow and you can see to the bottom of your well. Every day after that equinox, the sun will be off-vertical more and more at noon on the equator and will cast a longer and longer shadow each day until the solstice, where shadows would then get shorter until the next equinox.

If you’re a little above the equator, the day the sun casts no shadow at noon is a few days after the equinox, this day gets further and further from the equinox the more north or south you go (depending on the season). On the summer solstice, the place where the sun casts no shadow is along the Tropic of Cancer. It is the most northerly circle of latitude on Earth at which the Sun can be directly overhead. The same happens along the Tropic of Capricorn on the day of the winter solstice.

This is one of my favourite posts ever. Totally offtopic but amazing nonetheless.


Sent from my iPhone using Tapatalk
Title: Re: SpaceX FH : Falcon Heavy Demo : early 2018 : Discussion
Post by: russianhalo117 on 01/08/2018 09:50 PM