Falcon Heavy - General Discussion

[ecarfan]

That’s when the CEO suggested the possibility of a Falcon Super Heavy — a Falcon Heavy with extra boosters. “We could really dial it up to as much performance as anyone could ever want. If we wanted to we could actually add two more side boosters and make it Falcon Super Heavy,” Musk said.

With Musk also talking up how BFR construction has started and his very ambitious target for a first BFR launch in 2022, a Falcon Super Heavy seems like pure speculation that will never become reality. I assume it would require redesigning the center core to handle two more side cores and building a completely new TEL.

 

[KarenRei]

They'll make it if someone wants to pay them to make it. Aka, if NASA wants a super-heavy launch vehicle alternative to SLS block 1A/1B/2 with a short time frame and relatively little risk, they know where to turn.

 

[ecarfan]

if NASA wants a super-heavy launch vehicle alternative to SLS block 1A/1B/2 with a short time frame and relatively little risk, they know where to turn.

Fair point. But “short time frame” and “relatively little risk”? I think you are getting ahead of yourself. The FH hasn’t even flown yet. The likelihood that everything will go nominally is not high.

Developing an “FSH” will not be a simple matter. My point is that such a rocket could take years to develop and fly reliably for the reasons I pointed out. Given that SpaceX is committed to building the BFR and launching it by 2022*, and the BFR will be vastly more capable than a “Falcon Super Heavy”, I don’t see why SpaceX would divert resources to such a vehicle even if the US government provided money for it.

* Yes, the BFR likely will not fly by 2022. But that is the goal. Just like the goal was for the FH to fly 5 years ago.

 

[Nikxice]

I don't know what the impact could be on the possible development of a Falcon Super Heavy, but yesterday Musk stated that the FH is unlikely to ever carry astronauts. As Karen speculated, if someone else wants to put up the bucks, SpaceX would probably go for it. Elon's decision will undoubtedly cut costs by not having to certify a human-rated FH. If this decision holds true, the SLS just got a big boost, courtesy of Elon.

I imagine this could be end of the story for those two potential FH/Dragon 2 moon voyagers. Unfortunately, it might be time for them to seek their deposit refund.

Elon Musk Says SpaceX’s New Falcon Heavy Rocket Unlikely to Carry Astronauts

It looks like this story is behind a paywall. Googling 'SpaceX news WSJ' should bring up this WSJ article.

 

[Grendal]

I don't know what the impact could be on the possible development of a Falcon Super Heavy, but yesterday Musk stated that the FH is unlikely to ever carry astronauts. As Karen speculated, if someone else wants to put up the bucks, SpaceX would probably go for it. Elon's decision will undoubtedly cut costs by not having to certify a human-rated FH. If this decision holds true, the SLS just got a big boost, courtesy of Elon.

I imagine this could be end of the story for those two potential FH/Dragon 2 moon voyagers. Unfortunately, it might be time for them to seek their deposit refund.

Elon Musk Says SpaceX’s New Falcon Heavy Rocket Unlikely to Carry Astronauts

It looks like this story is behind a paywall. Googling 'SpaceX news WSJ' should bring up this WSJ article.

Elon backtracked on this. He told Loren Grush that if BFR gets delayed they can still man-rate FH and probably will. The impression from him is that BFR is moving so fast that it is unnecessary to get the FH rated for humans. Here is where he backtracked:

Loren Grush on Twitter

Musk: If BFR development takes longer than expected, SpaceX will return to the idea of putting crew on Falcon Heavy. But BFR is moving along quickly and FH won't need to be qualified for human spaceflight

Loren Grush on Twitter

The numbers on the website re: Falcon Heavy are for full Block 5 version. This Falcon Heavy is mostly Block 4. The next FH that flies will be Block 5

 

[bxr140]

They'll make it if someone wants to pay them to make it.

Especially with successful 'smaller' products like F9 and FH that could stage super heavy lifts, its hard to imagine FSH ever having a home unless BFR gets canned. Like BFR, there's simply no practical FSH payloads in the near term, and the "long term" on-ramp for BFR doesn't seem to be too far away. Then of course you have the diameter problem to deal with--a falcon core is only 3.7m wide and, as noted earlier (or maybe another thread) that's not conducive to bolting a whole mess of stuff on top of it. People might put a mailbox on a 4x4 post, but they don't ask the UPS guy to balance that package on a 4x4 post...

In an industry where non-recurring/dev plays such a massive part in any product (launcher or payload) and hundreds of millions of dollars (or more) are on the line for every mission, "Build it and they will come" is far easier said than done.

 

[KarenRei]

Like BFR, there's simply no practical FSH payloads in the near term, and the "long term" on-ramp for BFR doesn't seem to be too far away.

In Elon-Time, perhaps.

BFR is a massive technological change. Nobody has as of yet managed to make *any* orbital rocket with cryogenic propellants in CF tanks (despite several attempts), let alone the largest rocket ever built, let alone designed for a thousand uses per craft! And they're going to a brand new propellant mix with a brand new, full flow staged combustion engine. There is nothing simple about any of this. FSH is a much simpler thing to bring to life in the near term if there is ever need for it (which would almost certainly come from NASA, if it came).

Then of course you have the diameter problem to deal with--a falcon core is only 3.7m wide

Core doesn't matter. The fairing is 5,2m ID, 4,6m ID. And yes, fairing size matters for some things, but not everything. If NASA wants to launch, say, a probe to Planet X, they're going to need a metric hecktonne of propellant (or for ion propulsion, a nuclear reactor and some really heavy foldable radiators), but there's no need for the fairing to be particularly wide.

As for faring-to-core-size ratios, anyone remember the Titan IV?

It actually gets easier to have an oversized fairing, the more the cores you have.

 

[jbcarioca]

FH fueling just began

 

[KarenRei]

FH fueling just began

The suspense is killing me I'm trying to work on my tropical plants database in the meantime, but I keep thinking, "Is it time for the launch yet???"

 

[jbcarioca]

The suspense is killing me I'm trying to work on my tropical plants database in the meantime, but I keep thinking, "Is it time for the launch yet???"

RP-1 Fast Fill began 20 minutes ago, all is normal. supercooled LOX is now filling.42 minutes to go.
You can follow all this live with spaceflightnow.com but it does cost to see it live. If you're interested membership is cheap enough.

 

[Cosmacelf]

Success!

 

[HVM]

 

[Grendal]

Elon mentioned at the post launch conference that none of this rocket will be reused. Of the cores that flew, SpaceX wanted to recover the side boosters most because they had the reusable titanium grid fins. The next FH will be a Block 5.

 

[Unpilot]

I don't care if you a a Tesla hater or fan boy. This is freaking awesome. I could watch Starman all day!

 

[bxr140]

Core doesn't matter.

Primary modes are a thing. The CLA is everything. Wider = better. Obviously there’s different constraints on the fat side of things too, but the history of heavy launchers shows that 3.5-5m core for a 5m fairing is the obvious design space, with Titan IV being the low end outlier [that also has some unique characteristics that don’t translate to the modern launchers].

It actually gets easier to have an oversized fairing, the more the cores you have.

It’s more complicated than that. The extra ‘support structure’ definitely helps, but the obvious practical constraints of plopping a fat fairing on a skinny core become a problem. If I had to guess, I’d say a 7m fairing (and more importantly, the payload it represents) is probably about the limit for a falcon core.

 

[KarenRei]

Primary modes are a thing. The CLA is everything. Wider = better.

The point I was making was not that a wider core isn't better, it's that you don't put a payload inside the core - you put it inside a fairing, and the current standard Falcon fairing is 5,2m OD, 4,6m ID. Which is a pretty standard fairing size, you see pretty much the same thing from ULA, ESA/Ariane, the larger Russian launch vehicles, etc (China is working up towards that as well). The nice thing about there being so many launch options for that size is that you can design your payload for it and know that if one launch provider goes down, you can always switch to a different one. If SpaceX comes out with some massive fairing and you design your payload for it, then for whatever reason SpaceX has to stop flying, you're out of luck.

Larger fairings will be great, and I look forward to them. But you can do plenty with current fairings. And a larger fairing certainly isn't needed for FH's payload capacity to be useful.

 

[timk225]

I didn't read through 24 pages to see if anyone else mentioned this or not, but seeing the live views of Starman in the Tesla Roadster reminds me of the beginning of Heavy Metal.

 

[dpeilow]

Delta IV was always planned for a 7 core Super-Heavy variant (imagine the $$$). I always assumed SpaceX was thinking along the same lines until the BFR was proposed. Always made more sense to me to stockpile paid for 1st stages from commercial launches and gang them together to launch the fun stuff...

 

[tezzla]

With Musk also talking up how BFR construction has started and his very ambitious target for a first BFR launch in 2022, a Falcon Super Heavy seems like pure speculation that will never become reality. I assume it would require redesigning the center core to handle two more side cores and building a completely new TEL.

At a press conference last night, Elon said he plans to launch (test?) the BFR in 2019.

 

[bxr140]

The point I was making was not that a wider core isn't better, it's that you don't put a payload inside the core - you put it inside a fairing

...and the more important thing is that the payload gets attached to the core. The core is the payload load path.. The wider the core, the larger the potential payload, which of course needs a bigger fairing at some point. In context of a FSH--which is where this particular conversation started--the core, and specifically its ability to carry heavier and heavier loads becomes more and more of the limiting factor.

If SpaceX comes out with some massive fairing and you design your payload for it, then for whatever reason SpaceX has to stop flying, you're out of luck.

100% agree--that's the biggest hurdle for BFR IMHO Its definitely not a build-it-and-they-will-come situation unless its dirt cheap or has competition. Note that Spacex seems to be winning at 'dirt cheap'...

And a larger fairing certainly isn't needed for FH's payload capacity to be useful.

Agree, to a point. FH can potentially eliminate expendable missions, and since those are basically all GTO missions at this point [that are all built to the 5m fairing form factor] fairing size isn't a huge constraint for legacy GEO platforms. FH can also lift constellations (like all the internet ones, which are typically a bit higher than LEO but still low) at a lower price-to-orbit per unit, and its possible to max the mass in the 5m volume. That said, for both of those situations, the 5m fairing is really a design constraint on the form factor--in the case of the constellation, its a super frustrating design constraint that's more size than mass.

Anyway, FH's most practical limiting case is low orbit heavy lift, which is where my whole point comes together: You'd be hard pressed to find a low orbit payload that a) maxes out the lift capacity, b) fits in a 5m fairing, and c) doesn't break the CLA. A wider fairing enables all three of those factors but only to a point, and specifically (IMHO) a) breaks before c) for FH. So when you circle back to FSH, which solves the a) problem, you're left with c) being the limiting factor. So to horse beat my point: FSH is going to be limited by the falcon core's ability to carry a massive load.

Hence, BFR***.

***Or, you know, a million other things...like a super beefy central core...