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Falcon Heavy - General Discussion

bxr140

Active Member
Nov 18, 2014
3,310
5,634
Bay Area
WTF! "that they're not really doing anything revolutionary"


Reusability isn't a new concept. See: Space Shuttle. Spacex is just taking the concept to a new level. = evolution.

"spacex never having done this before", no, No one has done it before.

You're right, no one has ever put three spacex core stages in a hanger before.

We're talking about a picture here. Context, man.
 

Ben W

2008 Roadster, 2017 M3, 2022 MY
Feb 27, 2009
774
773
Santa Barbara, CA
Elon Musk tweet:

"Falcon Heavy side boosters can use most of the same airframe as Falcon 9, but center core needs to be buffed up a lot for transfer loads"

I wonder if it might be possible to connect the side cores directly to the 2nd stage (e.g. with load-bearing struts), to take some of the transfer loads off the center core? The advantage would be a lighter center core, perhaps allowing the same airframe for all three cores, and the struts themselves could detach at side-booster separation, so the center core wouldn't have to push the extra weight post-separation. (Also, less weight for the boostback/landing burns.)

Another idea: could the grid fins for the side cores be stowed inside the nose cap, to increase aerodynamic efficiency? I'm picturing the nose caps unfolding like flower petals and _becoming_ the grid fins, or at least becoming "flaps" to help the core decelerate as it reenters. Are the grid fins covered by fairings at launch to reduce drag?
 

VolkerP

EU Model S P-37
Jul 6, 2011
2,464
27
Germany
I understand that the key to increased payload mass is the amount of fuel left in the center core at the moment of booster separation. And how to reach this without propellant cross feed.
If FH requires a modified center core, SpaceX could increase its fuel capacity right from the start. The limit is lift-off weight < initial thrust.
 

ecarfan

Well-Known Member
Moderator
Yes, near the bottom of that page it shows this:
--------------------------------------------------------------
NovemberFalcon Heavy • Demo Flight
Launch window: TBD
Launch site: LC-39A, Kennedy Space Center, Florida
A SpaceX Falcon Heavy rocket will launch on its first demonstration flight. The heavy-lift rocket is formed of three Falcon 9 rocket cores strapped together with 27 Merlin 1D engines firing at liftoff. Delayed from 3rd Quarter of 2015 and April and September 2016. [March 16]
--------------------------------------------------------------

That will be awesome. No mention of any stage recovery attempts.
 

ggr

Expert in Dunning-Kruger Effect!
Moderator
Mar 24, 2011
7,237
31,013
San Diego, CA
I watched the Delta-4-Heavy launch of the NRO spysat the other day, and noticed that they also use the trick of full thrust on the outer cores while throttling the center core. Then they shed the outers and keep going with the center. I had thought it was SpaceX's idea, but I think D4H well predates them. Now I wonder whether the idea of crossfeed (sending fuel from the outer cores to the center one, which I don't think they are currently intending to do) was new to them or not?
 
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GoTslaGo

Learning Member
Dec 25, 2015
3,063
4,740
US
I watched the Delta-4-Heavy launch of the NRO spysat the other day, and noticed that they also use the trick of full thrust on the outer cores while throttling the center core. Then they shed the outers and keep going with the center. I had thought it was SpaceX's idea, but I think D4H well predates them. Now I wonder whether the idea of crossfeed (sending fuel from the outer cores to the center one, which I don't think they are currently intending to do) was new to them or not?

I'll have to watch that one again!
 
I watched the Delta-4-Heavy launch of the NRO spysat the other day, and noticed that they also use the trick of full thrust on the outer cores while throttling the center core. Then they shed the outers and keep going with the center. I had thought it was SpaceX's idea, but I think D4H well predates them. Now I wonder whether the idea of crossfeed (sending fuel from the outer cores to the center one, which I don't think they are currently intending to do) was new to them or not?
The idea's been around for quite a while. The Soviet Union's proposed UR-700 had a variant with crossfeeding, but it was never built:
UR-700
 

Grendal

SpaceX Moderator
Moderator
Jan 31, 2012
6,793
9,531
Santa Fe, New Mexico
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