SpaceX FH : Falcon Heavy Demo : Feb 6, 2018 : Discussion Thread 2

[ArdWar]

Hopefully this question is ok here. 

Considering that F9H and D4H are about the same size what is the primary reason for the performance differences?

DIV-H carry much less fuel mass than F9H

[Dolske]

Stunning and amazing. Congrats to SpaceX on a (so-far) successful launch and continued revolution of the launch industry!

[TrevorMonty]

That was awesume. 100% successful maiden launch of triple, incredible feat.

66% successful recovery still very impressive.

[Oersted]

If the center core didnīt make it (as some people are reporting) it actually just underlines that this was HARD! Too bad about the data they could have gotten from it, but... not important in the big picture.

[mlindner]

This is quite popular among general folk. My brother in Wisconsin just texted me saying,

 "My office is playing David Bowie music and will be showing the Falcon Heavy launch in the main presentation room on a 20ft screen".

He doesn't work in any industry related to space.

Update on my brother:

"My office erupted into cheers for the dual core landing" "Around 50 people watching"

[akfish]

The bottom views seems to be from the same booster. But if you look it closely, they are not identical. Looks like stereo camera to me.

Edit: added a screenshot

[miscme]

Outstanding Launch, worth staying up 5 hours past my bed time!

There was a 0.5 second shot of a view i have not seen before, any ideas what we are looking at here?

[GlassMoon]

Hopefully this question is ok here. 

Considering that F9H and D4H are about the same size what is the primary reason for the performance differences?

Delta IV uses Liquid Hydrogen, which has a density of about 70 kg/mģ.
Falcon 9 uses RP-1 (Kerosene), with a density of around 800-1000kg/mģ.
So they can fit around ten times the energy in the same volume.

[jimbowman]

One of the booster cams(top left) was getting pretty dirty

[llanitedave]

If the center core didnīt make it (as some people are reporting) it actually just underlines that this was HARD! Too bad about the data they could have gotten from it, but... not important in the big picture.

I wonder if the center core would be better off with the titanium grid fins as well.  Shame if it didn't make it, but that doesn't detract from the success overall.  Of all the fixes that they might have needed, this may end up being the easiest to correct.

[c4fusion]

Outstanding Launch, worth staying up 5 hours past my bed time!

There was a 0.5 second shot of a view i have not seen before, any ideas what we are looking at here?

I am guessing it's the mating point between the top of engine and the bottom of the upper stage.

[Kaputnik]

The announcer clearly states We lost the center core:

https://www.youtube.com/watch?v=wbSwFU6tY1c?t=38m25s

on the countdown net.

Might have just meant lost signal?

[abaddon]

Delta 4 Heavy weighs half as much as Falcon Heavy, but Delta 4 Heavy is a bigger rocket, physically.

The comparison all depends on whether Falcon Heavy is flown in recoverable mode or not. 

Right; Delta 4 Heavy really suffers in comparison to Falcon Heavy when operated in recoverable mode, as it gets 0 tonnes of payload to orbit.  However, it is far more fuel efficient than FH when operating this way, as it doesn't use any fuel at all.

[ugordan]

The announcer clearly states We lost the center core:

https://www.youtube.com/watch?v=wbSwFU6tY1c?t=38m25s

on the countdown net.

Might have just meant lost signal?

The webcast had the ASDS feed in the backrground with the sea bobbing etc, but no apparent hardware visible. FWIW.

[Oersted]

I wonder if the center core would be better off with the titanium grid fins as well.  Shame if it didn't make it, but that doesn't detract from the success overall.  Of all the fixes that they might have needed, this may end up being the easiest to correct.

Could also be that the beefing up of the structure was insufficient, or that it altered some characteristics... - Anyway, thatīs really secondary to this resounding success!

Would love to see a presser now.

[TomH]

Hopefully this question is ok here. 

Considering that F9H and D4H are about the same size what is the primary reason for the performance differences?

Energy density. Kerosene has a lot more energy per gallon of fuel than Hydrogen. Hydrogen has more energy per pound, but it is so light that it takes much larger tanks than kerosene. Given equal weights of Hydrogen and Kerosene, the Hydrogen has more energy, but that Hydrogen takes up much larger tanks. Given equal volumes of Kerosene and Hydrogen, the Kerosene has more energy. Kerosene is best utilized as a first state fuel. Hydrogen is best utilized as an upper state fuel. Methane is a good compromise AND it can be manufactured on Mars. That's why Musk's BFR Mars rocket will use Methane only.

[ricmsmith]

Usually when it takes this long to get word the landing was not successful. But wow, watching those two side cores landing simultaneously was just awesome, poetic even.

[Prettz]

If the center core didnīt make it (as some people are reporting) it actually just underlines that this was HARD! Too bad about the data they could have gotten from it, but... not important in the big picture.

Really too bad, lost all that wear data on the center core. I wonder why it didn't land, I would've thought that after the entry burn its descent is the same as any GTO mission.

[aero]

Maybe it is floating.

[lrk]

There is the off-chance the center core could be floating Remember, it is extra-reenforced after all, so it has an even better chance of surviving the tip-over.