Author Topic: SpaceX Falcon Heavy Discussion (Thread 2)  (Read 171814 times)

Online MP99

Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #40 on: 08/15/2014 08:54 AM »
OK, but that just increases the prop load on each booster by another 1.5t, when I was suggesting a bigger booster prop load, anyway.

Cheers, Martin

Offline UberNobody

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #41 on: 08/24/2014 11:12 PM »
Has anyone compiled a list of payload capability for Falcon Heavy?
Crossfeed vs no crossfeed, reusable vs expendable, LEO vs GTO etc?

Would be nice to have it all down in one place, what we know and what we don't know (and what we can guess).

Thanks in advance.

Offline wannamoonbase

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #42 on: 08/25/2014 02:33 AM »
Has anyone compiled a list of payload capability for Falcon Heavy?
Crossfeed vs no crossfeed, reusable vs expendable, LEO vs GTO etc?

Would be nice to have it all down in one place, what we know and what we don't know (and what we can guess).

Thanks in advance.

I don't have the numbers to produce a chart.  But I suggested a while ago that a plot be plotted, for a given inclination,  of payload mass versus altitude for he F9R, F9E, FHR, FHE, FHCF (or whatever all the possible FH combinations are, seems like many, if you get into crossfeed, partially reuseable, RTLS, Downrange recovery etc.)

Something like 4 or 5 different colors lines on an excel chart.  That could help a lot, but perhaps just lead to more debate.
I know they don't need it, but Crossfeed would be super cool.

Offline TrevorMonty

Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #43 on: 08/25/2014 03:05 AM »
Most of this information is in the thread if go back a few weeks. Alternatively try Wikipedia.

Offline Crews

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #44 on: 08/26/2014 05:38 PM »
Began following this discussion about midway through first thread-- with Boca Chica launch site, and followed since.

My question/thoughts...

Do we have any idea of the range of Falcon's (and Heavy) s1 boost?

For reusable, returning Falcon shot from Texas Coast, I am supposing that a near equivalent for first stage boost is the Saturn V, S1-- for about 400 miles/650 km, horizontal, from launch to splash.

That would place the boost phase plus momentum to surface of S1 almost due south of New Orleans-- the nearest land, and which is connected to Gulf Intracoastal Waterway back to Brownsville. 

Would not that be more efficient than a flying the return to Boca Chica (and more feasible than any attempt to reach Cape Canaveral-- as some had suggested)?

Otherwise, a floating platform would seem most cost effective for a landing site.

Then again, the Saturn comparison may not be close-- huge payload.

Offline Zed_Noir

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #45 on: 08/26/2014 09:05 PM »
...
Do we have any idea of the range of Falcon's (and Heavy) s1 boost?

For reusable, returning Falcon shot from Texas Coast, I am supposing that a near equivalent for first stage boost is the Saturn V, S1-- for about 400 miles/650 km, horizontal, from launch to splash.

That would place the boost phase plus momentum to surface of S1 almost due south of New Orleans-- the nearest land, and which is connected to Gulf Intracoastal Waterway back to Brownsville. 

Would not that be more efficient than a flying the return to Boca Chica (and more feasible than any attempt to reach Cape Canaveral-- as some had suggested)?
...
Not going to happen. To many populated areas along the flight path and around landing zone.

The authorities will have a very dim view of any large ballistic reentry objects near a metropolitan area like New Orleans.

Offline Crews

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #46 on: 08/27/2014 12:16 AM »
Not going to happen. To many populated areas along the flight path and around landing zone.

The authorities will have a very dim view of any large ballistic reentry objects near a metropolitan area like New Orleans.

Right.  Let me try again.

Brownsville is to Boca Chica as New Orleans is to [blank].  Lots of unused coastal, but channel accessible, land.  You need a landing pad/area, a crane, a tug and barge; and preferable, I would think, to a mid-Gulf platform as has been suggested.

What I am trying to discern is what are the abilities and likely geographic resources for the reusable Falcons flown out of Boca Chica.  It may be that all the way back to Boca Chica is what is intended.

Besides range of the S1, I'm also interested in launch declinations.  Think maybe I should take these questions to the Boca Chica thread-- but, in essence, they really are Falcon Heavy specific as the answers must be built on it's first stage abilities, both in boost and in return ranges.

And those, I have not read or seen discussed.

Offline dglow

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #47 on: 08/27/2014 01:48 AM »
Not going to happen. To many populated areas along the flight path and around landing zone.

The authorities will have a very dim view of any large ballistic reentry objects near a metropolitan area like New Orleans.

Right.  Let me try again.

Brownsville is to Boca Chica as New Orleans is to [blank].  Lots of unused coastal, but channel accessible, land.  You need a landing pad/area, a crane, a tug and barge; and preferable, I would think, to a mid-Gulf platform as has been suggested.

What I am trying to discern is what are the abilities and likely geographic resources for the reusable Falcons flown out of Boca Chica.  It may be that all the way back to Boca Chica is what is intended.

Besides range of the S1, I'm also interested in launch declinations.  Think maybe I should take these questions to the Boca Chica thread-- but, in essence, they really are Falcon Heavy specific as the answers must be built on it's first stage abilities, both in boost and in return ranges.

And those, I have not read or seen discussed.

Crews, I think I see where you're going/what you're asking, and I'm fairly certain it has been discussed. There is so much great discussion around here, it is difficult to follow all being said and nigh-impossible to come up-to-speed on that already said. The archives are deep, so no harm no foul.

Aside: if someone ever invents a magic piece of machine learning which generates summary-conclusions of online discussion... a 'here's the latest we know and how we got here, as well as the the most current-and-well-supported speculation' machine... well, NSF would be the place to beta-test it.

To your question: AFAIK, the only potential non-RTLS (non-Boca Chica) landing site for Boca Chica launches which has been realistically considered is the Florida Keys  and even then, only in the context of much larger, largely-theoretical rockets that SpaceX may build in the future. For F9 and FH launches, the Keys are too distant.

Launches from Boca Chica cannot cross over land and therefore must route between Florida and the Caribbean islands  what's called a dogleg maneuver. As such, New Orleans does not seem a likely landing site. More recently, some have speculated about the use of mobile landing platforms, e.g. barges, oil rigs, etc.

(All: please add to and/or correct this summary as best seen fit.)

Offline Darkseraph

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #48 on: 08/27/2014 02:29 AM »
I'm by no means an expert and I'm pulling this opnion out of the quantum vacuum fluctuations.....but I'll say it here. I don't think Falcon Heavy will be used for very many missions in the long run, esp if large methane engines are developed and first stage re-usability is proven doable and cost effective.


My haphazard reasoning goes that, nearly every Falcon launch so far has had problems. This vehicle has about three times as many potential problems thanks to its design. Landing a single core back on land is an impressive feat, but having that many stage separation and 3 core landings with 27 engines running perfectly sounds like a bridge too far and that a good few of them will fail.

In my mind, if they could prove reusability for the F9R and can successfully develop a large SC Methane engine, it might be better just to design a 5 meter core, 2 stage methane launcher with far fewer engines than 27 that can lift the largest plausible military and commercial commsats that will be needed in the next 15 years. Whatever there multiplanetary life plans are, those kinda of missions are going to be their bread and butter and it might be worth making a simpler reusable vehicle scaled for them that tests MCT technology before committing to things bigger than Saturn V. Such a vehicle doesn't even need to lift a ridiculous number to LEO like 53 tons or 20 odds ones to GTO, but could get more volume for mass than FH, making several possible lunar and neo missions a lot less hard to design. Given the current Raptor stats, such a vehicle might only need between 2 and 4 engines, or perhaps 9 if it was a smaller derivative of that technology.

That Golden Spike lander looks horrendous for the astronauts and basically not sustainable past the first few missions.

Anyway, I'm sure there are people here that are better with the numbers than me and could give specs for a more optimal vehicle.

EDIT: Okay, essentially what I'm advocating is something similar to the Falcon X that was proposes with a roughly similar diameter and engine count. That could put a good 38 tons into LEO with a 6 metre diameter, without being reusable or the higher ISP of methane. I suspect a similar vehicle, but with reusable with methane, given the payload hit would still be able to launch just about any Satellite of the near future and land back at the site with both stages.
« Last Edit: 08/27/2014 02:41 AM by Darkseraph »
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Online MP99

Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #49 on: 08/27/2014 08:30 AM »


Began following this discussion about midway through first thread-- with Boca Chica launch site, and followed since.

My question/thoughts...

Do we have any idea of the range of Falcon's (and Heavy) s1 boost?

For reusable, returning Falcon shot from Texas Coast, I am supposing that a near equivalent for first stage boost is the Saturn V, S1-- for about 400 miles/650 km, horizontal, from launch to splash.

That would place the boost phase plus momentum to surface of S1 almost due south of New Orleans-- the nearest land, and which is connected to Gulf Intracoastal Waterway back to Brownsville. 

Would not that be more efficient than a flying the return to Boca Chica (and more feasible than any attempt to reach Cape Canaveral-- as some had suggested)?

Otherwise, a floating platform would seem most cost effective for a landing site.

Then again, the Saturn comparison may not be close-- huge payload.

Elon has said that FH's core will overshoot Florida. (Not sure if that's only for the crossfeed version.)

Assuming that, most efficient mission design should be a braking burn shortly after MECO (in place of the boostback burn for F9 / FH boosters).

The advantage of this is that any speed reduction here will reduce size of the reentry burn.

ISTM the question is whether to land on East, South or West coasts of Florida. South is probably the lowest dV penalty, and easiest to avoid the IIP crossing Florida during the post-MECO burn.

Cheers, Martin

Offline llanitedave

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #50 on: 08/28/2014 03:32 PM »
I was pretty sure that it was agreed that the core would undershoot Florida.  My memory might be faulty, though.
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Offline guckyfan

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #51 on: 08/28/2014 05:07 PM »
I was pretty sure that it was agreed that the core would undershoot Florida.  My memory might be faulty, though.

Same with me on both parts. Undershoot the keys, that is. Overshooting would be good, though. They would have to do a brake/reentry burn and can chose the final touchdown point in a wide range with almost the same amount of fuel.

BTW Garrett Reisman seemed to know very little about Falcon Heavy in his presentation but he stated clearly, that FH would not be manrated, at least initially.

IMO it should not be too hard to add that capability, when required.

Online MP99

Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #52 on: 08/28/2014 06:49 PM »
I was pretty sure that it was agreed that the core would undershoot Florida.  My memory might be faulty, though.

Quote from: https://twitter.com/yatpay/statuses/330394578442133504
Is it possible to launch from Texas and land in Florida?

Quote from: https://twitter.com/elonmusk/statuses/330395232564826112
Side boosters fall short & center core goes too far + Florida is heavily populated. Landing permission tricky :)

Edit: if they can afford the sideways divert (and keep the IIP off land during the divert burn), they will have permission to land cores at CCAFS.

cheers, Martin
« Last Edit: 08/28/2014 06:52 PM by MP99 »

Offline Lars_J

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #53 on: 08/28/2014 06:55 PM »
Quote from: https://twitter.com/elonmusk/statuses/330395232564826112
Side boosters fall short & center core goes too far + Florida is heavily populated. Landing permission tricky :)

Edit: if they can afford the sideways divert (and keep the IIP off land during the divert burn), they will have permission to land cores at CCAFS.

That would be a *massive* sideways divert, that would take the IIP across many shipping lanes and flight corridors. (Can you imagine closing all that down?) That's not going to happen unless they can prove an exceptional safety record.

Online MP99

Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #54 on: 08/28/2014 07:12 PM »
Quote from: https://twitter.com/elonmusk/statuses/330395232564826112
Side boosters fall short & center core goes too far + Florida is heavily populated. Landing permission tricky :)

Edit: if they can afford the sideways divert (and keep the IIP off land during the divert burn), they will have permission to land cores at CCAFS.

That would be a *massive* sideways divert, that would take the IIP across many shipping lanes and flight corridors. (Can you imagine closing all that down?) That's not going to happen unless they can prove an exceptional safety record.

Had only thought about avoiding land, but sounds reasonable.

Will they have to clear shipping out of the "thread the needle" South of Florida?

Would it then be a relatively small extra imposition to transition across to a landing on the Southern tip of Florida?

cheers, Martin

Offline watermod

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #55 on: 08/28/2014 07:54 PM »
From the fiso mp3 it is obvious that the plumbing is different on the side boosters compared to the central core booster.
The central core was stated to be a standard F9.1 stack in every way.

This begs the question how many F9H vs F9 missions?

I suspect quite a few more F9s.

My cost reduction strategy would be to reuse "a many times used" F9 for the central core as an expendable on the F9H and just recover the side rockets. 

In the same discussion it was mentioned the Boca Chica is not intended for human flight.    That means you don't need to worry about abort landing sites for the Dragons.




Offline guckyfan

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #56 on: 08/28/2014 08:34 PM »
From the fiso mp3 it is obvious that the plumbing is different on the side boosters compared to the central core booster.
The central core was stated to be a standard F9.1 stack in every way.


The fiso mp3 showed clearly that Reissman knows very little about Falcon Heavy. He stated that the sidecores are the same as the central core and that is clearly not true. I don't see any reason why the plumbing of the side cores would be different as long as there is no crossfeed. And when there is crossfeed the plumbing of the central core needs to change too.


Offline mvpel

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #57 on: 08/28/2014 09:13 PM »
E-gad. If the FAA had been around in the early 1900's, airliners wouldn't be allowed to fly over cities at 37,000 feet, I suspect.
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Online Coastal Ron

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #58 on: 08/28/2014 09:37 PM »
From the fiso mp3 it is obvious that the plumbing is different on the side boosters compared to the central core booster.
The central core was stated to be a standard F9.1 stack in every way.


The fiso mp3 showed clearly that Reissman knows very little about Falcon Heavy.

Since your knowledge (and all of ours) lacks any real facts to determine whether what Reissman said is true or not, it would be premature to make that assessment.

Plus, he may have been generalizing for the audience.  For instance, the boosters have the same engines as the core, and the boosters have the same design and use the same tooling as the core.  So from a design standpoint they may in fact be 99% common from a functional standpoint, with the main difference being the attachment points.

Quote
He stated that the sidecores are the same as the central core and that is clearly not true.

Where do you get your facts from? Artist concepts?  But again, he could be generalizing.

Quote
I don't see any reason why the plumbing of the side cores would be different as long as there is no crossfeed. And when there is crossfeed the plumbing of the central core needs to change too.

Even with cross-feed they could run the plumbing through an insert at the bottom of the core where the plumbing already terminates at the engines.  That would simplify their plumbing off the LOX and RP-1 tanks.
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Offline Jim

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Re: SpaceX Falcon Heavy Discussion (Thread 2)
« Reply #59 on: 08/28/2014 09:44 PM »

He stated that the sidecores are the same as the central core and that is clearly not true.

Where do you get your facts from? Artist concepts?  But again, he could be generalizing.


They are longer than the core

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