Author Topic: Can Falcon Heavy handle a larger fairing? (Read 38214 times)

spacenut · « **on:** 04/04/2017 02:28 am »

If so how large? Seems like the existing fairing is size limited for heavy 50 ton payloads, like large Bigelow inflatable modules.

Arcas · « **Reply #1 on:** 04/04/2017 02:52 am »

The Falcon Heavy can't lift 50 tons anyways, so seems like a moot point.

cppetrie · « **Reply #2 on:** 04/04/2017 02:59 am »

Quote from: Arcas on 04/04/2017 02:52 am

The Falcon Heavy can't lift 50 tons anyways, so seems like a moot point.

In expendable mode it can do 54 tons to LEO.

spacenut · « **Reply #3 on:** 04/04/2017 03:37 am »

From what I read it was 54 tons in reusable mode to LEO. It can't lift that to GTO or GSO. That is after the upgrade to Full Thrust recently. Two outer boosters would land back at the Cape, center core would land on the drone ship. I just think they will eventually need a larger fairing if they are to launch heavy LEO payloads for someone.

MDDevice · « **Reply #4 on:** 04/04/2017 03:40 am »

How much does the fairing actually limit? I know it's too small for some Bigelow modules, but is there any other cargo that the FH wouldn't be able to carry? It seems like there's not many 50 ton payloads going to LEO but I haven't been paying much attention to proposals lately.

spacenut · « **Reply #5 on:** 04/04/2017 03:43 am »

Here is the SpaceX website:

http://www.spacex.com/falcon-heavy

54 tons to LEO, 22 tons to GTO, and 13 tons to Mars. I don't think they want to use 3 boosters in expendable mode, they would want to retrieve them. Someone on another area of this website said it was about 60 tons in expendable mode or more.

Anyway, they show using the same fairing for both F9 and FH. F9 has launched large satellites that took up almost the whole volume of the existing fairing. FH can do larger. Just wanting to know if some of these rocket engineers have figured out the maximum size fairing that FH could use.

cppetrie · « **Reply #6 on:** 04/04/2017 03:55 am »

Quote from: spacenut on 04/04/2017 03:43 am

Here is the SpaceX website:

http://www.spacex.com/falcon-heavy

54 tons to LEO, 22 tons to GTO, and 13 tons to Mars.

From discussions elsewhere on this site those numbers listed on the site do not include recovery and are essentially max payloads using expendable boosters. The most recent mass published for GTO with recovery is 8,300kg. That number hasn't changed since the debut of Full Thrust so it seems likely to have increased but not to 22,000kg. The prevailing thought seems to be that recovery limits GTO payload to about 13,000kg and probably ~25,000kg to LEO.

edkyle99 · « **Reply #7 on:** 04/04/2017 04:10 am »

The numbers currently on the SpaceX website are for Block 5 (which has yet to fly) in full expendable mode.

All you have to do is review launch history to sense the real, demonstrated capability of the current (apparently Block 3) Falcon 9. Its most recent launch was slightly sub-GTO (actually appears to have been a couple thousand km short of the planned apogee) with a 5.282 tonne payload and downrange first stage recovery. Its heaviest GTO payload was 5.6 tonnes in full expendable mode.

- Ed Kyle

Arcas · « **Reply #8 on:** 04/04/2017 04:43 am »

I seem to remember the Falcon Heavy being limited to a much lower payload than 50 tons due to the structural limits of the payload adapter.

Robotbeat · « **Reply #9 on:** 04/04/2017 04:49 am »

Quote from: Arcas on 04/04/2017 04:43 am

I seem to remember the Falcon Heavy being limited to a much lower payload than 50 tons due to the structural limits of the payload adapter.

That's only a limit of the bog standard adapter, not the launch vehicle. Not every payload uses that adapter. For instance: Dragon doesn't use the adapter.

It's not hard to make a different adapter.

rokan2003 · « **Reply #10 on:** 04/04/2017 05:55 am »

This reply by Musk about Falcon Heavy's payload capability:

@elonmusk Is the GTO payload still projected for 22,200 kilograms?

@jasonlamb looks like it could do 20% more with some structural upgrades to handle higher loads. But that's in fully expandable mode.

31/03/2017 20:54

Sent from my Passport using Tapatalk

IRobot · « **Reply #11 on:** 04/04/2017 05:59 am »

Quote from: Arcas on 04/04/2017 04:43 am

I seem to remember the Falcon Heavy being limited to a much lower payload than 50 tons due to the structural limits of the payload adapter.

Given those limitations and the recent comments of Musk, I wonder, if they could go back in time, probably they would probably just go for a wider first stage instead of 3 slimmer.

guckyfan · « **Reply #12 on:** 04/04/2017 06:05 am »

Quote from: IRobot on 04/04/2017 05:59 am

Quote from: Arcas on 04/04/2017 04:43 am
I seem to remember the Falcon Heavy being limited to a much lower payload than 50 tons due to the structural limits of the payload adapter.
Given those limitations and the recent comments of Musk, I wonder, if they could go back in time, probably they would probably just go for a wider first stage instead of 3 slimmer.

Using the Merlin/RP-1/LOX/metal tank architecture the FH still makes all kind of sense. Not so for the next generation with Raptor. But I am convinced the decision stands in hindsight.

John Alan · « **Reply #13 on:** 04/04/2017 06:13 am »

As to the original topic...
It likely could handle bigger...
BUT, I think they would farm it out and charge the customer at great expense for it...

Quote from: IRobot on 04/04/2017 05:59 am

Quote from: Arcas on 04/04/2017 04:43 am
I seem to remember the Falcon Heavy being limited to a much lower payload than 50 tons due to the structural limits of the payload adapter.
Given those limitations and the recent comments of Musk, I wonder, if they could go back in time, probably they would probably just go for a wider first stage instead of 3 slimmer.

THE number one reason why F9 is the size it is...

The cost and time needed to move it around is the lowest in the world... IMHO...

70 MPH cross country with a handful of people... Makes everyone else look silly in comparison...

Any bigger diameter... and it will add millions to the logistical expenses...

Rei · « **Reply #14 on:** 04/04/2017 08:33 am »

Quote from: MDDevice on 04/04/2017 03:40 am

How much does the fairing actually limit? I know it's too small for some Bigelow modules, but is there any other cargo that the FH wouldn't be able to carry?

Habitats... telescopes... the sort of things that you generally want a heavy launch vehicle for. I mean, the current fairing is fine for throwing big probes around the solar system and heavy satellites to GEO. And to be fair, their fairing size is basically industry standard. ~4,3-4,6m ID is very common for large launch vehicles the world over. Which is fine for most "traditional" payloads. But when you're looking to make use of heavy lift capacity, it is a bit limiting.

I've done some layouts for a Venus habitat, where most structures are fold-out and ambient pressure, but there was one enclosed, pressuretight section to act as a shelter when deployed / pressurized cargo storage during transit. Since it was smaller than the foldout areas, I had it be a lab, and since it was to double as a shelter, it had to include the toilet. Since you ideally don't want people to have to walk through the lab every time they wanted to use the toilet and you need privacy, this meant a dividing wall, an interior door, and ideally two exterior doors. Laying it out felt sort of like laying out an RV... "No, this door is going to run into that wall... what if we make these doors tiny and people have to sort of just turn around there... we have to move that wall back, they're not going to have any room to slide their chairs back over here..." etc. I mean, you can do it fine, but I'd hate to be constrained like that for long-term orbital, lunar, or Mars modules where everyone is inside them all the time. Even where you go for a horizontal layout, so that you have one long axis in the room, you still have to deal with total volume constraints.

And obviously for things like telescopes, the larger the fairing, the less convoluted James Webb-style origami you have to do.

If you engineer to a large fairing, and then the fairing or vehicle goes away, you're back to stage one. So you can engineer to a bit over 4m ID and trust that no matter what there will be something to launch it. But if you're engineering to a large fairing, you better work in close cooperation with the manufacturer and have faith in their ability to bring it to / keep it in service.

spacenut · « **Reply #15 on:** 04/04/2017 02:32 pm »

I was thinking about the Bigelow 330 module. At least a fairing large enough to get it to orbit. Or like someone said, a large telescope. Maybe even large components for a moon station. It would need a larger fairing to compete with SLS for some components.

Jim · « **Reply #16 on:** 04/04/2017 02:37 pm »

Quote from: John Alan on 04/04/2017 06:13 am

The cost and time needed to move it around is the lowest in the world... IMHO...
70 MPH cross country with a handful of people... Makes everyone else look silly in comparison...
Any bigger diameter... and it will add millions to the logistical expenses...

Unsupported statements. It would not add millions and it does not make others silly

abaddon · « **Reply #17 on:** 04/04/2017 02:45 pm »

Seriously, water transport is a little slow but it is not particularly expensive. Can we please not indulge in breathless hyperbole about everything SpaceX does?

spacenut · « **Reply #18 on:** 04/04/2017 03:56 pm »

Yes, I just want to know if the second stage as is, can handle a larger fairing. Wider and maybe a little longer for some larger future potential payloads like a 330 module. I know one of the Atlas V fairings encompasses the entire second stage. Just wondering if a 6m fairing say a little longer.

edkyle99 · « **Reply #19 on:** 04/04/2017 05:21 pm »

Quote from: spacenut on 04/04/2017 03:56 pm

Yes, I just want to know if the second stage as is, can handle a larger fairing. Wider and maybe a little longer for some larger future potential payloads like a 330 module. I know one of the Atlas V fairings encompasses the entire second stage. Just wondering if a 6m fairing say a little longer.

We can look at Titan 4 for an example of what has been done. Titan 4 carried a 200 in diameter fairing up to 1,067 inches long atop a 120 inch diameter core second stage. A 144 inch diameter Falcon 9 second stage might be expected to handle a fairing up to 240 inches (6.096 meters) diameter if the same relative diameter change were possible.

This does not answer whether the current Falcon 9 stage can structurally handle such a fairing. My guess would be that some changes would be needed, and of course the entire configuration would have to be qualified (wind tunnels, separation tests, etc.).

- Ed Kyle