NASASpaceFlight.com Forum

SpaceX Vehicles and Missions => SpaceX Starship Program => Topic started by: Ludus on 12/28/2015 09:36 pm

Title: Where will BFR launch from?
Post by: Ludus on 12/28/2015 09:36 pm
BFR as currently understood is too big to launch from 39a. It's also so big it should be assembled near the launch site even if the raptor engines are built elsewhere. Perhaps it should be transportable by water to alternate launch sites.

The factory can't be built until the launch site is decided. The intent of SpaceX is to be able to launch BFR in the early 2020's. So where will the BFR launch site be constructed?

Title: Re: Where will BFR launch from?
Post by: chalz on 12/28/2015 09:41 pm
Puerto Rico.

Can we make this thread last until the early 2020's?
Title: Re: Where will BFR launch from?
Post by: QuantumG on 12/28/2015 09:44 pm
Brownsville, Texas.
Title: Re: Where will BFR launch from?
Post by: science_business on 12/28/2015 09:44 pm
offshore platform
Title: Re: Where will BFR launch from?
Post by: AncientU on 12/28/2015 09:46 pm
One of the reasons given when SpaceX was negotiating for LC-39A was to have a pad for their BFR.  (That was a whole year and a half ago, so things might have changed.). Certainly the three core monster was not flying out of there, but a smaller version certainly could.  Accident analyses will need to compare the hazard of the proposed design with SLS (and STS) -- wouldn't count the BFR out just yet.

Note: There will likely be multiple pads for the BFR.  Above mentioned location(s) may all be correct.
Title: Re: Where will BFR launch from?
Post by: Bubbinski on 12/28/2015 09:56 pm
If BFR is reusable with landings, could a remote inland launch site be used? Like, say, Dugway, UT?
Title: Re: Where will BFR launch from?
Post by: Helodriver on 12/28/2015 10:03 pm
Building site, new factory located at former location of the Sea Launch Home port. Water transport to Vandenberg AFB where it will launch from SLC-6 once Delta IV heavy is retired.
Title: Re: Where will BFR launch from?
Post by: AncientU on 12/28/2015 10:05 pm
If BFR is reusable with landings, could a remote inland launch site be used? Like, say, Dugway, UT?

I would expect that a few hundred successful RTLS flights might make inland launches feasible.  The rest of the usual debris trails (such as fairings, etc.) would also have to be cleaned up... but BFR has a chance to do this.
Title: Re: Where will BFR launch from?
Post by: Mongo62 on 12/28/2015 10:06 pm
Boca Chica offshore platform.

It's too big for 39A, so that location is out. And I expect that SpaceX will want it well offshore of Boca Chica as well, to reduce noise impact and for a safety buffer zone. I believe that the Gulf there is fairly shallow to a considerable distance offshore, so constructing an above-water bridge/causeway and platform should not be TOO expensive.
Title: Re: Where will BFR launch from?
Post by: joek on 12/28/2015 10:24 pm
If BFR is reusable with landings, could a remote inland launch site be used? Like, say, Dugway, UT?

Unlikely.  Kistler was going to launch/land from an area in the Nevada Test Site, which with Nellis covers a lot more area and airspace than Dugway.  The ascent and descent trajectories were constrained (not to mention it was a relatively small vehicle).  You can find the primary FAA Kistler EIA documents here (http://www.faa.gov/about/office_org/headquarters_offices/ast/licenses_permits/media/document8.pdf) and here (https://www.faa.gov/about/office_org/headquarters_offices/ast/environmental/nepa_docs/review/launch/media/kistler_fonsi_042902.pdf).
Title: Re: Where will BFR launch from?
Post by: enzo on 12/29/2015 12:23 am
so constructing an above-water bridge/causeway and platform should not be TOO expensive.
Why not throw in a relatively cheap volcano-based launch facility as well? Excellent sound suppression.
Title: Re: Where will BFR launch from?
Post by: science_business on 12/29/2015 01:02 am
It has been reported that spacex contracted with a large oceanography/civil engineering firm to do unspecified research. This leads me to suspect the offshore option. Plus room is needed for future expansion beyond BFR.

The easiest way to colonize mars successfully is to transport insanely large payloads way beyond terrestrial scale.
In effect you are transporting an entire city from earth to mars. The Europeans could not do that with north america, but surprisingly we could do this with Mars if we only had the will. I think Musk has the will.
Title: Re: Where will BFR launch from?
Post by: M_Puckett on 12/29/2015 01:25 am
so constructing an above-water bridge/causeway and platform should not be TOO expensive.
Why not throw in a relatively cheap volcano-based launch facility as well? Excellent sound suppression.

(http://www.jonsnow.youthconnect.in/wp-content/uploads/2015/06/i-see-what-you-did-there-futurama-fry-sneaky-sneak-Hk7gda_zps290ac531.jpg)
Title: Re: Where will BFR launch from?
Post by: JamesG123 on 12/29/2015 02:07 am
If BFR is reusable with landings, could a remote inland launch site be used? Like, say, Dugway, UT?

I don't think even Elon Musk could get the FAA and NASA to sign off on THAT launch license.

I would guess Tejas.
Title: Re: Where will BFR launch from?
Post by: Jdeshetler on 12/29/2015 03:49 am
Nomadd's frontyard...
Title: Re: Where will BFR launch from?
Post by: jfallen on 12/29/2015 03:59 am
I like the volcano option.  Sound suppression plus super-billionaire cred, no down sides.  Plus if you have a submarine car a volcano lair is the next logical step.
Title: Re: Where will BFR launch from?
Post by: mnelson on 12/29/2015 04:27 am
It's too big for 39A, so that location is out.

Pardon my ignorance, what makes it too big for 39A? Is it a range safety concern with that much fuel/oxidizer in one spot? Insufficient flame trench? Too big for the transporter/erector? Blockhouse not far enough away?
Title: Re: Where will BFR launch from?
Post by: Zed_Noir on 12/29/2015 05:32 am
Building site, new factory located at former location of the Sea Launch Home port. Water transport to Vandenberg AFB where it will launch from SLC-6 once Delta IV heavy is retired.

Or you could build the factory at ex-NAS Alameda in San Francisco and embark the BFR onto RoRo transport ships to floating launch facilities off Hawaii's big island.

If the BFR is too big for LC-39A than SLC-6 is probably to small as well. Especially if the BFR core is 15+ meter diameter.
Title: Re: Where will BFR launch from?
Post by: Mongo62 on 12/29/2015 12:22 pm
It's too big for 39A, so that location is out.

Pardon my ignorance, what makes it too big for 39A? Is it a range safety concern with that much fuel/oxidizer in one spot? Insufficient flame trench? Too big for the transporter/erector? Blockhouse not far enough away?

Pad 39A was built to handle a maximum thrust of 12.5 Mlb at takeoff (Saturn V was 7.65 Mlb at takeoff, Nova-class launcher would have been around 12 Mlb), while BFR is said to be around 15 Mlb thrust -- double that of a Saturn V.
Title: Re: Where will BFR launch from?
Post by: Llian Rhydderch on 12/29/2015 01:21 pm
It has been reported that spacex contracted with a large oceanography/civil engineering firm to do unspecified research. This leads me to suspect the offshore option. Plus room is needed for future expansion beyond BFR.

The easiest way to colonize mars successfully is to transport insanely large payloads way beyond terrestrial scale.
In effect you are transporting an entire city from earth to mars. The Europeans could not do that with north america, but surprisingly we could do this with Mars if we only had the will. I think Musk has the will.

Reported how?  Do you have a source?
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 12/29/2015 01:28 pm
Large scale civil engineering/oceanography? Sounds like a possible artificial island or peninsula? Interesting idea, and makes sense. Gives them a nice buffer while still allowing them to launch from terra firma.

...could also be a reference to firming up parts of their Boca Chica launch site. The roads are sometimes flooded over there already. And if this launch site is supposed to last through the rest of the century, then the flooding will only get worse due to sea level rise, so they'll want to take that into account.
Title: Re: Where will BFR launch from?
Post by: rst on 12/29/2015 01:47 pm
Building site, new factory located at former location of the Sea Launch Home port. Water transport to Vandenberg AFB where it will launch from SLC-6 once Delta IV heavy is retired.

If you just want to get maximum mass into orbit, Vandenberg isn't the best place to start:  you want the rocket heading eastward, to take the boost from the earth's rotation, but a rocket going straight east from Vandenberg goes over populated land uncomfortably close to Los Angeles.  It's possible to launch into an east-going orbit from Vandenberg, but it requires a dog-leg trajectory, heading south over water, then turning east; that expends fuel.  (Vandenberg's mostly used for launches into polar or high-inclination orbits, for which this isn't an issue.)

So, if you want to launch from Vandenberg into a parking orbit, with the ultimate destination of Mars, doing it from Vandenberg has a nontrivial payload penalty, and there'd have to be some really compelling advantage to make up for that.  I'm not sure pre-existing facilities would do -- they've already got access to the largest available pre-existing pad and GSE at LC39 (where no odd dog-legs are needed), and if that's big enough, they'll just use it there.
Title: Re: Where will BFR launch from?
Post by: Ludus on 12/29/2015 03:47 pm
I suspect the politics of local and environmental impact will be a major factor. Launching a rocket that's quite a bit bigger than a Saturn 5 and returning it to the launch site will potentially stir up a lot of opposition.

That suggests that KSC/Canaveral have an edge because it's not a scary novelty and the local economy is already oriented to be supportive.

Brownsville might come to be more like this after years of operations but I don't know if there's time for that to happen before they have to start construction.

Might they build a new pad at 39, I guess it would be "d"? They did originally plan for more than the two pads that got built for Apollo. I'm sure there would still be objections but that's the one place it's not a scary novelty.
Title: Re: Where will BFR launch from?
Post by: Ben the Space Brit on 12/29/2015 04:11 pm
I'll say this much: The lead time required for a pad to launch a 10m/33'-diameter core that uses cryogenic fuel and could withstand regular launches at >Saturn-V thrust would probably be 5 years at least so, one way or another, SpaceX needs to already be looking at sites.

Is LC-39C's never-used site still extant and available?
Title: Re: Where will BFR launch from?
Post by: RonM on 12/29/2015 04:15 pm
Building platforms and causeways a few kilometers offshore of Brownsville is the way to go. Far enough offshore to be safe and not too loud, but not too far so tourists can still see the launch from the beach. If the platform was 10 m above sea level, you could still see it from the beach up to about 12 km away. That's over twice the distance of the LC39 Press Site from the pads.
Title: Re: Where will BFR launch from?
Post by: science_business on 12/29/2015 04:43 pm
I searched for the article, but did not spend a lot of time....It was out of Long Beach i believe.
Title: Re: Where will BFR launch from?
Post by: Kansan52 on 12/29/2015 04:52 pm
I'll say this much: The lead time required for a pad to launch a 10m/33'-diameter core that uses cryogenic fuel and could withstand regular launches at >Saturn-V thrust would probably be 5 years at least so, one way or another, SpaceX needs to already be looking at sites.

Is LC-39C's never-used site still extant and available?

Strangely enough, some of the history says 39-c was built and renamed 39-a.

But the land is still there but no third, fourth, ect pads were ever started. Looking at the map, if SpaceX could get permission for land south of the 39-a, bird's eye view says that would be best and they could use the same barge channel that SLS will use.

Politics, environment, soil conditions, ect may rule that out. North of 39-b might be more available.
Title: Re: Where will BFR launch from?
Post by: TomH on 12/29/2015 05:55 pm
I'll say this much: The lead time required for a pad to launch a 10m/33'-diameter core that uses cryogenic fuel and could withstand regular launches at >Saturn-V thrust would probably be 5 years at least so, one way or another, SpaceX needs to already be looking at sites.

Is LC-39C's never-used site still extant and available?

Strangely enough, some of the history says 39-c was built and renamed 39-a.

But the land is still there but no third, fourth, ect pads were ever started. Looking at the map, if SpaceX could get permission for land south of the 39-a, bird's eye view says that would be best and they could use the same barge channel that SLS will use.

Politics, environment, soil conditions, ect may rule that out. North of 39-b might be more available.

The initial map showed five pad locations in Complex 39. Beyond A and B, NASA only actually gave consideration to C. Environmental regulations today could make construction in any of the remaining three areas difficult. Though it seems counterintuitive, the area also is a wildlife sanctuary.
Title: Re: Where will BFR launch from?
Post by: Nomadd on 12/29/2015 10:32 pm
Nomadd's frontyard...
If it gets rid of those Fire ants, I'm all for it.
Title: Re: Where will BFR launch from?
Post by: Bob Shaw on 12/29/2015 10:39 pm
From what I've read about the BFR, the thing is so huge that it can take off from wherever it wants, and land wherever it wants, too. Don't argue with it!
Title: Re: Where will BFR launch from?
Post by: Saabstory88 on 12/29/2015 11:00 pm
I would agree with the offshore sentiment if it were not for some of the less frequently remembered words uttered by Elon. He want's all of the above to be largely automated. I don't think we will see a solution which requires any shipping of stages farther than an electric automated stage transporter can ferry it. I imagine that conceptually, the launch site will be structured like so:

[Landing Pad] -> [Processing Facility] -> [Launch Pad]
                                     ^
                                     ||
                                [Factory]

Not exactly conducive to a sea based platform, unless we are talking Dubai artificial island scales here. This sort of automation, and co-location of facilities is arguable just as important as being able to get the stages back to land.
Title: Re: Where will BFR launch from?
Post by: RonM on 12/30/2015 02:46 am
I would agree with the offshore sentiment if it were not for some of the less frequently remembered words uttered by Elon. He want's all of the above to be largely automated. I don't think we will see a solution which requires any shipping of stages farther than an electric automated stage transporter can ferry it. I imagine that conceptually, the launch site will be structured like so:

[Landing Pad] -> [Processing Facility] -> [Launch Pad]
                                     ^
                                     ||
                                [Factory]

Not exactly conducive to a sea based platform, unless we are talking Dubai artificial island scales here. This sort of automation, and co-location of facilities is arguable just as important as being able to get the stages back to land.

Offshore pads connected to shore by a bridge.
Title: Re: Where will BFR launch from?
Post by: chalz on 12/30/2015 03:39 am

[Landing Pad] -> [Processing Facility] -> [Launch Pad]
                                     ^
                                     ||
                                [Factory]

Not exactly conducive to a sea based platform, unless we are talking Dubai artificial island scales here. This sort of automation, and co-location of facilities is arguable just as important as being able to get the stages back to land.

Sea borne TEL.

[Landing Pad] -> [Processing Facility] -> [Ferry trip] -> [Launch Pad]
                                     ^
                                     ||
                                [Factory]
Title: Re: Where will BFR launch from?
Post by: Vultur on 12/30/2015 07:09 am
Far enough offshore to be safe

I remember someone posting on this forum that recent study had shown that old numbers for liquid-rocket safe distances were massively over-stated because liquid fuels can't really mix sufficiently to detonate well... is that correct? If so, what would the safe distance for a (say) 2x Saturn V fuel load really be like?
Title: Re: Where will BFR launch from?
Post by: WmThomas on 12/30/2015 03:41 pm
All this talk about fancy off-shore launch site is probably way off base.

Elon is very focused on costs and convenience. His MO is to re-use existing infrastructure if at all possible.

Since the pad that can launch BFR doesn't exist, it will have to be built. But you can bet it will be built on land.

The two most likely candidates are near Boca Chica (Brownsville) or at the Cape.

Title: Re: Where will BFR launch from?
Post by: Jcc on 12/31/2015 01:36 pm
All this talk about fancy off-shore launch site is probably way off base.

Elon is very focused on costs and convenience. His MO is to re-use existing infrastructure if at all possible.

Since the pad that can launch BFR doesn't exist, it will have to be built. But you can bet it will be built on land.

The two most likely candidates are near Boca Chica (Brownsville) or at the Cape.

I agree, but I wonder how big a buffer zone really is needed? Boca Chica seems unlikely to have enough undeveloped land, especially to prevent the buffer zone from extending into Mexico. There should be a big enough buffer at the Cape, but the problem there is you would need new dredge and fill permits to destroy a chunk of wetland, which were easy to come by in the 60's but not so much now.

The other thing that worries me about the Cape is competition for range availability. My understanding is that it takes days to reconfigure the range monitoring equipment to monitor a particular launch, which will be a bigger and bigger constraint as more launch providers use the Cape. If that system were upgraded, then they ought to be able to do a launch a day during clear weather, why not?

I guess one way to find more buffer space at Boca Chica is to build an artificial island in the middle of South Bay, which would still require a new dredge and fill permit, but could create new wetlands to mitigate any destroyed ones.
Title: Re: Where will BFR launch from?
Post by: RedLineTrain on 12/31/2015 02:08 pm
The South Bay idea is interesting.  But any move away from civilization seems to include more involvement with the Mexican authorities.  Could be tricky.

Edit:  I understand that there are a few huge LNG terminals being planned for construction near the Brownsville Ship Channel.  Would have to check that.
Title: Re: Where will BFR launch from?
Post by: modemeagle on 12/31/2015 04:12 pm
Far enough offshore to be safe

I remember someone posting on this forum that recent study had shown that old numbers for liquid-rocket safe distances were massively over-stated because liquid fuels can't really mix sufficiently to detonate well... is that correct? If so, what would the safe distance for a (say) 2x Saturn V fuel load really be like?

I think you are right. Lemme put it this way.  The press observation gantry at pads 39 feels like it would have been waaaaaaay too close for comfort if a Saturn 5 rocket or the Shuttle actually exploded when people were standing there!

Oh, and this:  http://forum.nasaspaceflight.com/index.php?topic=35248.msg1236646#msg1236646

I think they could put a raised causeway and integrated facility near Houston or Brownsville and be just fine miles off-shore with that shallow water.  Though the Florida Coast does have obvious advantages as SpaceX_MS has stated in the past (http://forum.nasaspaceflight.com/index.php?topic=35419.msg1307505#msg1307505).

Attached shows the flight paths from each pad.  Not sure if they will want to build an offshore launch site that is in the path of other launching vehicles.  One bad day for those launches could cause a bad day for SpaceX too.  The only place I could see that would be safe is north of 39A and B.
Title: Re: Where will BFR launch from?
Post by: MickQ on 12/31/2015 11:16 pm
From what I've read about the BFR, the thing is so huge that it can take off from wherever it wants, and land wherever it wants, too. Don't argue with it!

And you call it "Sir ".
Title: Re: Where will BFR launch from?
Post by: philw1776 on 01/01/2016 04:31 pm
Nomadd's frontyard...
If it gets rid of those Fire ants, I'm all for it.

Brings to mind "THEM".  Just hope firing off huge methalox rockets doesn't modify the ants DNA and...
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 01/01/2016 05:43 pm
I recall that, back in 1961, when NASA was still debating the lunar landing mode decision, Debus and Petrone were tasked with figuring out how what would become the Launch Operations Center (later to be renamed KSC) would launch the vehicles being discussed for Apollo.

Von Braun had come up with a high flight rate model for Saturn vehicles, assuming the need to salvo-launch as many as three or four C-4's to support a single lunar expedition.  This high flight rate assumption is what led to the VAB/crawler architecture that was eventually adopted.

However, for Nova (had Direct Ascent been chosen for Apollo), the assumption had always been that it would have a flight rate of one to two flights per year, so it would be assembled and launched from an offshore launch platform.  Without any need for a high flight rate, Nova would not need the VAB/crawler approach, and so would have a removable scaffolding surrounding it during assembly.

The interesting and applicable point to all of this is that early NASA thinking on the stacking and launching of Nova, which is the only vehicle ever proposed that is even a moderate fraction of the size of the BFR, was that it would be stacked at, and launched from, an offshore platform.

I think this makes an offshore platform a good bet for a launch complex for the BFR.  However, because Musk will be going for a high flight rate model, I'd bet that the BFR gets assembled onshore and transported via causeway to the offshore launch platform, rather than being stacked on the pad.

Offshore from KSC, CCAFS, Boca Chica/Brownsville (i.e., far south Texas), even the Virginia coast or Hawaii, could be good bets for a BFR launch site if it needs to be on American soil.  If not, there are any number of locations across the world that lay closer to the equator, giving BFR and MCT a performance boost they may need to accomplish their missions.  Unlike NASA looking for a launch site for, say, Apollo, SpaceX isn't necessarily limited to launching its own Mars colonization missions from American soil, eh?
Title: Re: Where will BFR launch from?
Post by: meekGee on 01/01/2016 06:23 pm
I recall that, back in 1961, when NASA was still debating the lunar landing mode decision, Debus and Petrone were tasked with figuring out how what would become the Launch Operations Center (later to be renamed KSC) would launch the vehicles being discussed for Apollo.

Von Braun had come up with a high flight rate model for Saturn vehicles, assuming the need to salvo-launch as many as three or four C-4's to support a single lunar expedition.  This high flight rate assumption is what led to the VAB/crawler architecture that was eventually adopted.

However, for Nova (had Direct Ascent been chosen for Apollo), the assumption had always been that it would have a flight rate of one to two flights per year, so it would be assembled and launched from an offshore launch platform.  Without any need for a high flight rate, Nova would not need the VAB/crawler approach, and so would have a removable scaffolding surrounding it during assembly.

The interesting and applicable point to all of this is that early NASA thinking on the stacking and launching of Nova, which is the only vehicle ever proposed that is even a moderate fraction of the size of the BFR, was that it would be stacked at, and launched from, an offshore platform.

I think this makes an offshore platform a good bet for a launch complex for the BFR.  However, because Musk will be going for a high flight rate model, I'd bet that the BFR gets assembled onshore and transported via causeway to the offshore launch platform, rather than being stacked on the pad.

Offshore from KSC, CCAFS, Boca Chica/Brownsville (i.e., far south Texas), even the Virginia coast or Hawaii, could be good bets for a BFR launch site if it needs to be on American soil.  If not, there are any number of locations across the world that lay closer to the equator, giving BFR and MCT a performance boost they may need to accomplish their missions.  Unlike NASA looking for a launch site for, say, Apollo, SpaceX isn't necessarily limited to launching its own Mars colonization missions from American soil, eh?

That's a good analysis.

I'll add one thing though.  Equatorial launch is important when you have a rocket that has capacity X, and you absolutely need to launch 1.05X.  (In terms of mass or dV or whatever).

(I don't remember the exact value of the equatorial boost - the ground velocity at the equator is 1000 miles/day, which is not very much, and it's not like the ground velocity at Latitude 30 is a lot less...

But the mission here is to colonize Mars, which will take hundreds of flights (if not more).  So unless there's some atomic unit that is too large for BFR, the difference between X and 1.05X is simply between flying 100 times and flying 105 times...  So if launching from TX or FL has logistical advantages, the equatorial boost is a secondary consideration.
Title: Re: Where will BFR launch from?
Post by: CuddlyRocket on 01/01/2016 07:07 pm
... SpaceX isn't necessarily limited to launching its own Mars colonization missions from American soil, eh?

I suspect those enforcing the ITAR regulations would have something to say about that.
Title: Re: Where will BFR launch from?
Post by: kch on 01/01/2016 07:10 pm

Equatorial launch is important when you have a rocket that has capacity X, and you absolutely need to launch 1.05X.  (In terms of mass or dV or whatever).

(I don't remember the exact value of the equatorial boost - the ground velocity at the equator is 1000 miles/day, which is not very much, and it's not like the ground velocity at Latitude 30 is a lot less...

Ground velocity at the equator is more like 1000 miles/hour (calculator gives 1047 for Earth diameter of 8000 miles); at 30 degrees latitude it'd be closer to 866 (again, calculator gives 906).  In either case, it's a significant boost ... and a good reason to not launch over the poles (or, worse yet, retrograde) unless you really need to do so.



But the mission here is to colonize Mars, which will take hundreds of flights (if not more).  So unless there's some atomic unit that is too large for BFR, the difference between X and 1.05X is simply between flying 100 times and flying 105 times...  So if launching from TX or FL has logistical advantages, the equatorial boost is a secondary consideration.

Agreed.
Title: Re: Where will BFR launch from?
Post by: meekGee on 01/01/2016 07:18 pm

Equatorial launch is important when you have a rocket that has capacity X, and you absolutely need to launch 1.05X.  (In terms of mass or dV or whatever).

(I don't remember the exact value of the equatorial boost - the ground velocity at the equator is 1000 miles/day, which is not very much, and it's not like the ground velocity at Latitude 30 is a lot less...

Ground velocity at the equator is more like 1000 miles/hour (calculator gives 1047 for Earth diameter of 8000 miles); at 30 degrees latitude it'd be closer to 866 (again, calculator gives 906).  In either case, it's a significant boost ... and a good reason to not launch over the poles (or, worse yet, retrograde) unless you really need to do so.



But the mission here is to colonize Mars, which will take hundreds of flights (if not more).  So unless there's some atomic unit that is too large for BFR, the difference between X and 1.05X is simply between flying 100 times and flying 105 times...  So if launching from TX or FL has logistical advantages, the equatorial boost is a secondary consideration.

Agreed.

You are right of course, but still - you get 1000 miles/hr at the equator, about about .88 of that at latitude 28, right?    So the difference is 120 miles/hr?

Orbital plane has little to do with it, since you're presumably not launching to LEO but to some high parking orbit (if not L2)
Title: Re: Where will BFR launch from?
Post by: kch on 01/01/2016 07:24 pm

You are right of course, but still - you get 1000 miles/hr at the equator, about about .88 of that at latitude 28, right?    So the difference is 120 miles/hr?

Right.  :)
Title: Re: Where will BFR launch from?
Post by: meekGee on 01/01/2016 07:30 pm

You are right of course, but still - you get 1000 miles/hr at the equator, about about .88 of that at latitude 28, right?    So the difference is 120 miles/hr?

Right.  :)

So hence the point - does that speed (~54 m/s) really justify launching out of remote launch sites? 

I think given all the logistics of the Mars colonization campaign, they will launch from the mainland.  I do like the idea of an off-shore launch pad, as it get around a lot of issues.   If you're going to build one from scratch (as opposed to re-purposing an existing pad like 39A) then it makes a lot of sense.  And if you're going to build a few of them, then even more so.
Title: Re: Where will BFR launch from?
Post by: kch on 01/01/2016 07:46 pm

You are right of course, but still - you get 1000 miles/hr at the equator, about about .88 of that at latitude 28, right?    So the difference is 120 miles/hr?

Right.  :)

So hence the point - does that speed (~54 m/s) really justify launching out of remote launch sites? 

I think given all the logistics of the Mars colonization campaign, they will launch from the mainland.  I do like the idea of an off-shore launch pad, as it get around a lot of issues.   If you're going to build one from scratch (as opposed to re-purposing an existing pad like 39A) then it makes a lot of sense.  And if you're going to build a few of them, then even more so.

As you stated above -- and I agreed (still do!):


... if launching from TX or FL has logistical advantages, the equatorial boost is a secondary consideration.
Title: Re: Where will BFR launch from?
Post by: Ludus on 01/01/2016 11:20 pm
Since the launch platform would be a few miles offshore a causeway that could handle heavy traffic would be very costly and just floating large things out to it would be easy. SpaceX wants launch as automated as possible so presumably few people would work on the platform to set up for launch.

Any notions what an offshore launch site would be like? Artificial island like Dubai or South China Sea or a platform on legs? Was there a design for Nova?
Title: Re: Where will BFR launch from?
Post by: CraigLieb on 01/02/2016 09:56 pm
where is there enough space for the factory? This is the primary consideration which may drive the launch location. It seems Boca Chica/Brownsville tx area is ripe for the development. Land is cheap, the coast in that region is already approved for a launch site. Why wouldn't they just build their new site to be able to launch F9, FH and allow for the design flexibility to accommodate BFR as a growth option?
Challenges abound to be sure including ground stability, additional environmental impacts, and sufficient qualified labor in the area. And Nomadd may need another set of ear plugs...😳😉
Title: Re: Where will BFR launch from?
Post by: Dave G on 01/04/2016 05:44 am
My guess: BFR will be built at the Brownsville seaport.  From there, it can be shipped to any coastal launch site.

Why would SpaceX want to build BFR in Brownsville?

1) Cost of living is one of the lowest in the nation.  That means inexpensive labor for locally hired machinists, construction workers, secretaries, security guards, electricians, janitors, etc., etc.  Lowering costs is a major goal for SpaceX.  Affordable labor aligns with that goal.  My guess: Of the 100 or so people working at a BFR assembly plant, perhaps only 12 would need to be imported.  The rest could be local hires.  Note: This assumes Raptor engines, avionics, etc. are still manufactured in Hawthorne.  Brownsville would just do the large tank manufacturing and core assembly.

2) World class seaport, capable of handling huge ships (aircraft carriers, oil drilling rigs, etc.).  Setting up a manufacturing facility along this port would easily allow BFR to be shipped to the KSC, VAFB, etc.   There's also a new road specifically built to handle freight to/from the seaport, bypassing Brownsville's city center.

3) An international airport for getting people to/from Brownsville, and for air freight.  Note that this airport is just 5 miles from the seaport.  Very convenient.  They're also going to extend the main runway in order to handle large air freight.

4) A state university campus with a budding space engineering department.  Note that SpaceX and UT Brownsville are already working together on the STARGATE tracking center, just 2 miles from the launch site.  Lots of future synergy also possible there.

5) Some local talent.  The area now has some local aerospace machine shops, and ULA also has a manufacturing plant just 15 miles away in Harlingen.

6) Available land is plentiful and cheap.  Lots of room to expand.  Low property taxes.  Low taxes in general.

7) Clean slate.  Many have played down Brownsville as not having enough existing infrastructure for an aerospace manufacturing plant, but for SpaceX, this may actually be a perceived advantage.  For cost and schedule reasons, SpaceX has often steered clear of established aerospace companies.

To be clear, Brownsville wouldn't have been my first thought for building rockets, but after digging deeper, it seems to have all the right ingredients.

Title: Re: Where will BFR launch from?
Post by: docmordrid on 01/04/2016 07:08 am
My guess: BFR will be built at the Brownsville seaport.  From there, it can be shipped to any coastal launch site.

Why would SpaceX want to build BFR in Brownsville?
>
>
that

Not that mention that Musk mentioned building their large launcher near the launch site during his Texas state legislature testimony, this in the runup to SpaceX's launch site selection. I don't remember seeing heavy industrial support infrastructures equivalent to Brownsville in Puerto Rico or many other places mentioned as alternatives.

https://youtu.be/3_iu75TFgX8
Title: Re: Where will BFR launch from?
Post by: guckyfan on 01/04/2016 07:08 am
My guess: BFR will be built at the Brownsville seaport.  From there, it can be shipped to any coastal launch site.

Why would SpaceX want to build BFR in Brownsville?

I was thinking of that wedge shaped area where SpaceX and the State of Texas already own most of the lots.

(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=35425.0,3Battach=1090961,3Bimage.pagespeed.ic.Wdp3Pkzm_u.jpg)
Title: Re: Where will BFR launch from?
Post by: Lobo on 01/04/2016 09:54 pm
It's too big for 39A, so that location is out.

Pardon my ignorance, what makes it too big for 39A? Is it a range safety concern with that much fuel/oxidizer in one spot? Insufficient flame trench? Too big for the transporter/erector? Blockhouse not far enough away?

Unless it's over 20m wide, it won't be too "big" for 39A.

It might be too "powerful".  But if Elon's old statement if 15Mlbs of thrust is still relatively accurate, 39A may be able to be upgraded to accommodate that.  It was built to handle up to a 12Mlbs of thrust Nova class Rocket originally as I understand.  So with some upgrades and mods it's plausible it could handle 20% more thrust.

KSC would be my bet...it's already a BFR launch site, with an outside chance of SLC-6 at VAFB.  Althouigh there are some trajectory issues from there.  Location is good to have room to launch and recover big rockets.

I Think Boca Chica will handle their comsat business with Falcon, along with LC-40 and SLC-4E.  And not be upgraded to the sort of operation needed for MCT.  I think we'd see something form SpaceX by now on EIS's or something for LV's and operations of that scale in that area.  They are already getting a lot of push back for just F9 and FH scale.

Title: Re: Where will BFR launch from?
Post by: Robotbeat on 01/04/2016 11:57 pm
They'd have to totally rebuild LC39A at this point since I believe they filled in part of the flame trench with cement. They'd be better off at a clean site with no pad than demolishing LC39A and starting from scratch.
Title: Re: Where will BFR launch from?
Post by: guckyfan on 01/05/2016 09:03 am
Would they even consider a site where they would have to compete for launch slots with ULA and BlueOrigin? That may be ok for early testing but not for operations.

As they cannot launch from the Cape without building massive infrastructure that seems to be out too. Unless SLS is cancelled, they can get LC39B for cheap and can launch with a throttled version from there for early testing. Not a likely scenario IMO.
Title: Re: Where will BFR launch from?
Post by: bstrong on 01/07/2016 01:57 am
How about Kourou? I suspect the flight rate will be dropping precipitously there in a few years, and ESA might welcome a new tenant to help pay the bills (well, maybe not exactly welcome, but be forced to resort to, perhaps).

ITAR doesn't seem to restrict the launch of US satellites from there, so presumably US rockets would be OK, too? Not a super high likelihood, but I would add it to the list.
Title: Re: Where will BFR launch from?
Post by: go4mars on 01/07/2016 03:48 am
LNG is at sea.  Oxygen can be shipped in essentially the same way.
Cruise ships can either just supply interested spectators, or provide "orientation training" for the 80,000 colonists per synodic period.   
If 105 mass units can be launched each time by equator plus down range landing barges instead of 100, then it's clearly worth thinking through. 

The ocean is more NIMBYless than almost anywhere in US territory.

Peter Thiel still has influence and SpaceX shares - and is a founder of the seasteading institute. 
A sea-stead can be a lower risk, lower cost, high volume proof of concept demonstrating Mars crops, recycling, and other tech's.   

I guess I like the idea of a sales-pitch training and launch flotilla that pays for itself, while testing things needed for Mars - maybe even eventually including political experiments that reward and accelerate innovation - as the seasteading institute founders hope. 

I like the concept anyway.

Cheers.

http://forum.nasaspaceflight.com/index.php?topic=35419.msg1307630#msg1307630
Title: Re: Where will BFR launch from?
Post by: dorkmo on 01/07/2016 06:15 am
perhaps theyll make a dual use take off/landing mega barge.

being at sea is a pain but with enough planning the benefits seem to be there to exploit.
Title: Re: Where will BFR launch from?
Post by: bstrong on 01/07/2016 03:51 pm
I'd be interested in hearing opinions on Cumberland County, GA as a potential BFR launch site, per the info on the new EIS filing (for F9, not BFR) here:

http://forum.nasaspaceflight.com/index.php?topic=31525.msg1471313#msg1471313

Launch pad is here in the FAA docs:

https://goo.gl/maps/pzknwW1VexH2
Title: Re: Where will BFR launch from?
Post by: RonM on 01/07/2016 06:16 pm
I'd be interested in hearing opinions on Cumberland County, GA as a potential BFR launch site, per the info on the new EIS filing (for F9, not BFR) here:

http://forum.nasaspaceflight.com/index.php?topic=31525.msg1471313#msg1471313

Launch pad is here in the FAA docs:

https://goo.gl/maps/pzknwW1VexH2

Piney Bluff is about five miles away. Jekyll Island is over six miles away from the launch site. The area around Kings Bay Naval Base is about seven miles away. They might have to buy more land to cover it, but I think it would work.

Maybe it will be too loud for some of the residents at Piney Bluff and I'll be able to get a tidal marsh house for cheap.  :)
Title: Re: Where will BFR launch from?
Post by: Prettz on 01/07/2016 09:02 pm
Supposing that they wanted to launch it from an ocean platform like Sea Launch, does there currently exist any such platforms big enough to handle the BFR? Like, especially, one with a big open area near the center, large enough for all the first stage's engines to blow straight down into the water?
Title: Re: Where will BFR launch from?
Post by: go4mars on 01/08/2016 01:14 am
Supposing that they wanted to launch it from an ocean platform like Sea Launch, does there currently exist any such platforms big enough to handle the BFR? Like, especially, one with a big open area near the center, large enough for all the first stage's engines to blow straight down into the water?
Like the Allseas 72,000 tonne lifting boat?

Edit: A quick Google shows that "Amazing Grace" (72 Mt) won't be operational until 2021. It's still being designed.  Primarily for decommissioning huge top sides in the North Sea in a single lift - which apparently is much safer and cheaper.  Plenty of time to add some blast shielding and GSE...   Right?  🚢🚀🚀🚀

It's little sister - "Pioneering Spirit" seems to be out and about.  It has a 48 Gigagram lifting capacity. 
It's the biggest boat by gross tonnage.
Title: Re: Where will BFR launch from?
Post by: sghill on 01/08/2016 05:05 pm
Far enough offshore to be safe

I remember someone posting on this forum that recent study had shown that old numbers for liquid-rocket safe distances were massively over-stated because liquid fuels can't really mix sufficiently to detonate well... is that correct? If so, what would the safe distance for a (say) 2x Saturn V fuel load really be like?

I think you are right. Lemme put it this way.  The press observation gantry at pads 39 feels like it would have been waaaaaaay too close for comfort if a Saturn 5 rocket or the Shuttle actually exploded when people were standing there!

Oh, and this:  http://forum.nasaspaceflight.com/index.php?topic=35248.msg1236646#msg1236646

I think they could put a raised causeway and integrated facility near Houston or Brownsville and be just fine miles off-shore with that shallow water.  Though the Florida Coast does have obvious advantages as SpaceX_MS has stated in the past (http://forum.nasaspaceflight.com/index.php?topic=35419.msg1307505#msg1307505).

Attached shows the flight paths from each pad.  Not sure if they will want to build an offshore launch site that is in the path of other launching vehicles.  One bad day for those launches could cause a bad day for SpaceX too.  The only place I could see that would be safe is north of 39A and B.

That's a cool overlay.  Thanks!

But it misses the point though that once you use a causeway and get the actual launch and landing pads off shore, you can put the launch facilities pretty much anywhere that it makes sense to have the onshore factory, processing, and training facilities- and the most important piece, a willingness of the surrounding public to have them there. 

Once they get the launch pad off of the coast, SpaceX doesn't have to go to Brownsville- they could go to Houston!  Or Jacksonville. Or Savannah. etc....

The difference in cost of this type of complex is mostly the raised causeway- and I addressed it's cost in the link above.  The development time and environmental approval savings are huge if a community wants the facility without putting up with noise and dangers of a land launch.

Title: Re: Where will BFR launch from?
Post by: Ludus on 01/16/2016 10:17 pm
It's not obvious that there's any need for a causeway connecting to an offshore launch site. It would be one of the most expensive elements and mostly serve the need for regular travel by lots of personnel. Large objects are better transported by water anyway. Automation significantly reduces the need to move people on a regular basis.
Title: Re: Where will BFR launch from?
Post by: OxCartMark on 01/19/2016 03:34 am
The search for an appropriate place on the planet to have such a facility is seemingly being limited in this discussion by a few assumptions that I don't think are necessarily necessary.  Do we need a big 39A/B style pad?  It seems if the goal is to launch large numbers of these BFRs in a short period of time you'd need a prohibitive(ly expensive) number of pads and they'd each need to be separated by so much distance that the facility would become bigger than even the bigness being assumed.  I'd be looking for a novel launch method and one that doesn't have the ground in close proximity to the blast, requiring a flame trench, water spray etc.  Examples of such concepts would be (just tossing out some quick ideas not real suggestions) a launch from a high platform (like a scaled up version of the tripod they have at McGregor) surrounded by unprepared ground, Launching from a hastily built platform between two catamaraned ship hulks, launching from water immersion (see Sea Dragon), launching from the landing pad with perhaps legs that come off shortly thereafter (to get enough clearance to not fry the pad surface).  I'm betting the upcoming Mars architecture will have more novel architecture than just the flying bits.  Neil Armstrong didn't need a launch pad to get off the moon.  MCT won't use a launch pad to get off the surface of Mars.  All of those 1950s version of the future rockets didn't need launch pads.  BFR will find a way to do it using something much less expensive and more quickly recyclable than a conventional launch pad.
Title: Re: Where will BFR launch from?
Post by: sghill on 05/06/2016 02:05 pm
It's not obvious that there's any need for a causeway connecting to an offshore launch site. It would be one of the most expensive elements and mostly serve the need for regular travel by lots of personnel. Large objects are better transported by water anyway. Automation significantly reduces the need to move people on a regular basis.

Yes, a causeway is extremely expensive, but it brings the on-going expense of moving workers, fuel, and materials back and forth to the pad to next to zero when compared to moving things by boat.  Flexibility goes way up when you can drive out there in five minutes to work on something. Moving things by boat is expensive, dangerous, and slow.
Title: Re: Where will BFR launch from?
Post by: Ludus on 05/14/2016 09:08 pm
By mass, the biggest share of stuff going out to a launch platform is propellant, LOX and liquid methane. I've got no idea what the difficulties and limitations of that are. I assume that tanks out at a platform are too dangerous but can they be piped for miles?
Title: Re: Where will BFR launch from?
Post by: llanitedave on 05/15/2016 12:22 am
By mass, the biggest share of stuff going out to a launch platform is propellant, LOX and liquid methane. I've got no idea what the difficulties and limitations of that are. I assume that tanks out at a platform are too dangerous but can they be piped for miles?


Yes, they often are.
Well, at least crude oil is.

http://www.marineinsight.com/offshore/how-single-point-mooring-spm-offshore-operation-works/ (http://www.marineinsight.com/offshore/how-single-point-mooring-spm-offshore-operation-works/)
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/15/2016 12:46 am
I don't see the problem with tanks out at a platform.
Title: Re: Where will BFR launch from?
Post by: Helodriver on 05/15/2016 01:10 am
My money is on LC-39A. Its those giant rainbirds that make me think it. Over on SLC-4E at Vandenberg they are installing new rainbirds that are sized for F9FT and FH operations and they are not nearly so big, or strongly reinforced. My thought is they will upgrade the launch stand for BFR when the time comes perhaps after Boca Chica is up and running or maybe there is another F9/FH class pad somewhere else.

As we've seen at SLC-3W, Omelek, LC-40 and SLC-4E SpaceX is not adverse to building launch stands often and abandoning them even after few uses as vehicles evolve and plans change.

I also believe Musk is respective of space history and launching the first crewed missions to Mars, from the same pad that launched the lunar missions, a pad that's now his, just feels right.
Title: Re: Where will BFR launch from?
Post by: FishDaddyFlex on 05/15/2016 08:00 am
Im in the boat of starting basically from scratch but keeping it on land.  Upgrading 39 seems like an enormous effort.  I dont even know how possible it is without basically scrapping the old pad.  Not to mention the construction/upgrade time would take away a potential launch site from Space-X's regular commercial launches (although the Texas site might take that need away). 

Why not lease another essentially abandoned pad (or 2 adjacent pads as some of the other pads are significantly smaller compared to 39)?  Those pads look relatively simple to build upon or rip out and start over with.  My ideal pad would be LC-46 but I dont know if that is possible/available.  It has a large area available to expand, appears it would be the safest point to launch from (most eastern tip of the Cape), and hasn't been used since 1999.... although launches are planned for the next two years.  I dont know for sure, but I might be able to see a route from the "Turn Basin" all the way to LC-46 if rocket components had to be brought in by ship.
Title: Re: Where will BFR launch from?
Post by: MP99 on 05/15/2016 02:44 pm
Boca Chica is the obvious location, but seems too close to the village to be viable.

This makes me think of an offshore pad.

Possibly a ship that's loaded onshore, then moves to the launch location. Possibly with a foundation on the seabed and it lifts itself to provide stability.

Could be a barge - plenty of space below-decks to install prop tanks.

While there's no need for the factory to be close by the launch site, putting it at Boca Chica does reduce the cycle time before the next launch, since that seems to be their ambition.

Cheers, Martin
Title: Re: Where will BFR launch from?
Post by: mattstep on 05/15/2016 03:06 pm
If SpaceX were thinking of using 39a for BFR, wouldn't that show up in their lease agreement with NASA?  Is their usage of the pad constrained in any way (thrust at liftoff, noise, etc.)?
Title: Re: Where will BFR launch from?
Post by: The Amazing Catstronaut on 05/15/2016 03:10 pm


I also believe Musk is respective of space history and launching the first crewed missions to Mars, from the same pad that launched the lunar missions, a pad that's now his, just feels right.

Are the rainbirds big enough for BFR?  Sure, you could always install more, but is there anything in the immediate area that BFR would be an unacceptable acoustic hazard to?

If one blows up, it'll make N1 look like Antares.
Title: Re: Where will BFR launch from?
Post by: dorkmo on 05/15/2016 04:47 pm
Im going to bet $5 that it'll launch/land on a mega ASDSheavyv1.3FT within 1,000 miles of Kiritimati https://en.wikipedia.org/wiki/Kiritimati

and theyll load it in long beach
Title: Re: Where will BFR launch from?
Post by: darkenfast on 05/16/2016 06:22 am
There was an approximately three-mile area kept clear around the 39 pads during Saturn V launches.  A BFR will need more than that.  Draw a circle with a four or five mile radius around the launch site at Boca Chica.  Does it run into anything (including an international border)?  If it does, you have a problem with that location that must be addressed.
Title: Re: Where will BFR launch from?
Post by: Zed_Noir on 05/16/2016 10:51 am
Im going to bet $5 that it'll launch/land on a mega ASDSheavyv1.3FT within 1,000 miles of Kiritimati
More likely within 100 miles (160 km) of the Hawaii Big Island. If SpaceX pick the offshore launch option. It is a lot easier to move people and logistics needed to support BFR launches to Hawaii than setting up & supporting floating logistics and accommodation complexes in the middle of the Pacific. For example how do you move the propellants required to the middle of the Pacific and store them there?

Quote
and theyll load it in long beach
::)
Just the little matter of getting the BFR core to Long Beach. The transport infrastructure is not capable handling a 8.4 meter core never mind the BFR's rumor 15+ meter core.

So SpaceX will most likely load the BFR directly from where ever they put down their seaside BFR assembly facility.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 05/16/2016 02:17 pm
Im going to bet $5 that it'll launch/land on a mega ASDSheavyv1.3FT within 1,000 miles of Kiritimati
More likely within 100 miles (160 km) of the Hawaii Big Island. If SpaceX pick the offshore launch option. It is a lot easier to move people and logistics needed to support BFR launches to Hawaii than setting up & supporting floating logistics and accommodation complexes in the middle of the Pacific. For example how do you move the propellants required to the middle of the Pacific and store them there?

Quote
and theyll load it in long beach
::)
Just the little matter of getting the BFR core to Long Beach. The transport infrastructure is not capable handling a 8.4 meter core never mind the BFR's rumor 15+ meter core.

So SpaceX will most likely load the BFR directly from where ever they put down their seaside BFR assembly facility.

Boca Chica still makes sense to me.  You can site your BFR construction/assembly facilities there, you can set up your propellant creation/storage equipment there (i.e., liquefying the LOX and sub-cooling the propellants), and you can do your refurb on returned stages there.

You can build the launch pads as platforms out into the Gulf, three or four miles from the beach, and build appropriately robust causeways out to the pads.  These pads would be far enough away from population and facilities on-shore to protect them from a Bad Day on the pad, and still keep all the facilities clustered close enough together to support the prodigious launch rates SpaceX seems to be planning for their Mars architecture.

I'm thinking that Boca Chica will end up being Spaceport Earth within the SpaceX Mars architecture, I really am...
Title: Re: Where will BFR launch from?
Post by: Thorny on 05/16/2016 03:05 pm
I'm thinking that Boca Chica will end up being Spaceport Earth within the SpaceX Mars architecture, I really am...

Why limit yourself to such a narrow launch azimuth, though?
Title: Re: Where will BFR launch from?
Post by: spacenut on 05/16/2016 03:44 pm
The Gulf of Mexico is shallow, so building a launch platform a mile or two offshore isn't impossible.  Also, the LNG and LOX facilities can be onshore and piped out to the platform, or liquefied on site with facilities on the platform, and the natural gas and oxygen gas just piped underwater to he platform.  A bridge may not even be necessary, one for security, two hovercraft can carry people to and from the platform quickly.  The BFR can be built and assembled in Brownsville and shipped to the platform, in short time.  The American production and infrastructure can bring all the parts together quickly at Brownsville, engines, avionics, etc, for assembly. 

Also, with the Gulf being shallow and the water not so choppy as the Atlantic can be, landing on a large ocean going barge or even another platform further out at sea, wouldn't be a big problem, brought back to Brownsville for refurbishment, and sent back for another launch. 

Any facility further away from the America infrastructure would be problematic and shipping costs would be greater.  Brownsville is about as far south as you can get and still be connected to the American infrastructure of roads, intercoastal waterway, shipping, pipelines, communications, airport, and communications.  Texas would probably help put up some money for any infrastructure needed to get the manufacturing and jobs, to increase it's tax base. 

Because of the above opinion, only the Cape facilities would be the next logical location.  Vandenburg is for mostly polar orbits, getting a BFR flying east over populated areas would be a problem. 

Another area of consideration would be somewhere in the Florida Keys.  However, that area has more people, is geared for tourism, and not for industry.   Nearest potential industrial facilities would be near Miami, which is further away than Brownsville from a potential launch site.  Weather can be worse there also. 
Title: Re: Where will BFR launch from?
Post by: The Amazing Catstronaut on 05/16/2016 04:50 pm
What about a mile long artificial island/causeway with the pad at the end? Means you don't need to load the assembled BFR on any boats - just roll it out there and raise it up. Load passengers after erection.



Title: Re: Where will BFR launch from?
Post by: Zed_Noir on 05/16/2016 05:49 pm
Im going to bet $5 that it'll launch/land on a mega ASDSheavyv1.3FT within 1,000 miles of Kiritimati
More likely within 100 miles (160 km) of the Hawaii Big Island. If SpaceX pick the offshore launch option. It is a lot easier to move people and logistics needed to support BFR launches to Hawaii than setting up & supporting floating logistics and accommodation complexes in the middle of the Pacific. For example how do you move the propellants required to the middle of the Pacific and store them there?

Quote
and theyll load it in long beach
::)
Just the little matter of getting the BFR core to Long Beach. The transport infrastructure is not capable handling a 8.4 meter core never mind the BFR's rumor 15+ meter core.

So SpaceX will most likely load the BFR directly from where ever they put down their seaside BFR assembly facility.

Boca Chica still makes sense to me.  You can site your BFR construction/assembly facilities there, you can set up your propellant creation/storage equipment there (i.e., liquefying the LOX and sub-cooling the propellants), and you can do your refurb on returned stages there.

You can build the launch pads as platforms out into the Gulf, three or four miles from the beach, and build appropriately robust causeways out to the pads.  These pads would be far enough away from population and facilities on-shore to protect them from a Bad Day on the pad, and still keep all the facilities clustered close enough together to support the prodigious launch rates SpaceX seems to be planning for their Mars architecture.

I'm thinking that Boca Chica will end up being Spaceport Earth within the SpaceX Mars architecture, I really am...

Your point was discuss on previous thread. It is doable if you can attracted enough workers to South Texas to manned the assembly facility. However SpaceX was sited in South California because they have hard time getting the L.A. talent pool to move to the Bay area AIUI. 
 
Title: Re: Where will BFR launch from?
Post by: philw1776 on 05/16/2016 06:16 pm
What about a mile long artificial island/causeway with the pad at the end? Means you don't need to load the assembled BFR on any boats - just roll it out there and raise it up. Load passengers after erection.   :P

That should make at least some BFR passengers REALLY happy!

Seriously, the launch needs to be maybe 6-8 miles offshore given the exclusion zone for the much smaller Saturn V.  Ocean depths are only 100 or so feet there.  I don't know what it costs to place a large platform in say 120 ft deep relatively shallow ocean.
Causeway is capital expensive but tug barges aren't for propellant, BFRs, etc. with hydrofoils to shuttle workers.

Title: Re: Where will BFR launch from?
Post by: oldAtlas_Eguy on 05/16/2016 06:22 pm
What about a mile long artificial island/causeway with the pad at the end? Means you don't need to load the assembled BFR on any boats - just roll it out there and raise it up. Load passengers after erection.
In an launch rate environment of a launch per week this would be sufficient to warrant the costs of such a civil engineering endeavor. But first is there any close to this as a natural feature?

Added: As a bit history perspective on a new BFR pad. Boca Chica from start of environmental assessment in 2012 to operational status in 2018 is 6 years!!!! A new pad in a new area takes a lot of time. And the BFR pad will be 3-4 times the size of Boca Chica.

So the survey and pick of a site must be ongoing now with a narrowing and possible start of a environmental assessment to be started in 2018 for support of a first BFR launch in NET 2024/2025. That would be the schedule taht would support the original flying in 10 years stated in 2014/2015.
Title: Re: Where will BFR launch from?
Post by: Bob Shaw on 05/16/2016 06:34 pm

In an launch rate environment of a launch per week this would be sufficient to warrant the costs of such a civil engineering endeavor. But first is there any close to this as a natural feature?


Several possibilities:

(a) A tombolo

(b) A coral atoll

(c)  A coral barrier reef

(d) Tidal mud flats with causeways
Title: Re: Where will BFR launch from?
Post by: RonM on 05/16/2016 06:38 pm
What about a mile long artificial island/causeway with the pad at the end? Means you don't need to load the assembled BFR on any boats - just roll it out there and raise it up. Load passengers after erection.
In an launch rate environment of a launch per week this would be sufficient to warrant the costs of such a civil engineering endeavor. But first is there any close to this as a natural feature?

An artificial island would be too expensive, a massive engineering project. They make sense for Dubai where the water is only a few meters deep. Off the coast of Brownsville is shallow for platforms, but too deep for an artificial island.

A bridge to the platform would be convenient, but the question is would it be cheaper than a barge and crane? The platform would need to be far enough offshore, several kilometers, making a bridge expensive.
Title: Re: Where will BFR launch from?
Post by: oldAtlas_Eguy on 05/16/2016 06:51 pm
What about a mile long artificial island/causeway with the pad at the end? Means you don't need to load the assembled BFR on any boats - just roll it out there and raise it up. Load passengers after erection.
In an launch rate environment of a launch per week this would be sufficient to warrant the costs of such a civil engineering endeavor. But first is there any close to this as a natural feature?

An artificial island would be too expensive, a massive engineering project. They make sense for Dubai where the water is only a few meters deep. Off the coast of Brownsville is shallow for platforms, but too deep for an artificial island.

A bridge to the platform would be convenient, but the question is would it be cheaper than a barge and crane? The platform would need to be far enough offshore, several kilometers, making a bridge expensive.
Using a barge in a high launch rate system (once a week or even more often) is not cost effective compared to a bridge even though the bridge represents a high capitol cost up front with its cost spread across 50+ flights/yr over 4 years could be lower than the cost of operating a barge, cranes, ports, handling equipment etc per flight. Plus a bridge could easily outlast a barge representing a gradual decrease in costs per flight when using a bridge vs a forever constant  and possibly increasing amount when using barges etc.
Title: Re: Where will BFR launch from?
Post by: JasonAW3 on 05/16/2016 07:00 pm
I'm thinking a barge going out to a platform, hoisted up, barge and all, lifted to the vertical.  Might even be able to make the barge part of the actual launch tower.
Title: Re: Where will BFR launch from?
Post by: RDMM2081 on 05/16/2016 07:13 pm
My vote is Boca Chica, on land.  My ignorant bliss is telling me that by the time they begin launching BFR, they will have a track record established, and "accommodations" will be made in the interest of getting a lot of stuff to Mars, really quickly.  I still think we are at least 6 years from BFR first launch, they have plenty of time to establish their track record and earn these hypothetical "accommodations".
Title: Re: Where will BFR launch from?
Post by: The Amazing Catstronaut on 05/16/2016 08:10 pm


That should make at least some BFR passengers REALLY happy!



Well, if you don't, it'd be entertaining.
Title: Re: Where will BFR launch from?
Post by: spacenut on 05/16/2016 08:55 pm
Oil platforms are built every day.  That isn't as big a problem as it seems.  Huge platforms were built for the North Sea, and the Gulf is way easier. 

As far as environmental issues.  What does our jurisdiction extend to 3 miles, 6 miles.  A platform could be just inside international waters, to avoid any environmental issues.  Actually oil platforms add structure to the sea and increases marine life around the structure.  However, a rocket firing would run fish off, or some type of acoustics could scare the fish off before a launch.  Pipelines can carry the fuel and lox.  There is a large natural gas pipeline running from Texas to Tampa all under the gulf to avoid land environmental issues. 

Also taking out passengers and cargo by boat or hydrofoil would probably be cheaper than building a bridge out to the platform. 

Once this area develops for Falcon 9's and Falcon Heavies, more people will move to the area.  By the time BFR gets going, Brownsville and the surrounding area might grow to the size of Houston.  Dearborn, Michigan was just a farm town until Ford built a factory there.  Birmingham was just a farm town, until they found iron ore, with both coal and limestone nearby.  Build it and they will come. 
Title: Re: Where will BFR launch from?
Post by: Kansan52 on 05/16/2016 09:13 pm
In addition to other Gulf platforms mention, there are floating platforms that era tether to the sea floor.
Title: Re: Where will BFR launch from?
Post by: dorkmo on 05/16/2016 11:11 pm
do we know if bfr will be rtls?
Title: Re: Where will BFR launch from?
Post by: philw1776 on 05/16/2016 11:59 pm
do we know if bfr will be rtls?


We KNOW little about BFR but informed speculation based on calculations suggests it's easier & cheaper to build a BFR that does droneship landings..  Boostback eats propellant. 
Title: Re: Where will BFR launch from?
Post by: Chris Bergin on 05/17/2016 01:28 am
The smart money is on the Yorkshire Coast, Northern England.

What? At least I'd get a bloody webcam set up! ;D
Title: Re: Where will BFR launch from?
Post by: Impaler on 05/17/2016 02:34 am
A location few miles offshore similar to an oil-platform seems reasonable.  I would imagine it would simply have a doughnut hole in the middle and use the water as a giant flame-trench.

A causeway normally means a pile of Earth emerging out of the water with a linear transport infrastructure on it, I think people might have meant a viaduct which is a series of pillars supporting said infrastructure.  Closely spaced supporting pylons won't allow ships to pass but because this is a projection into the open ocean this is no problem and it significantly reduces the cost.  In addition the viaduct can be designed to only support the well distributed weight of the BFR's empty stage, that weight can distributed over a distance longer then the rocket itself.  Lets estimate the rocket masses 200 mt dry and a carrying sled is likewise 200 mt but 200 m long, the viaduct only needs to support 2 mt per meter length.

The BFR would certainly need to be transported on it's side down the causeway and the carrying vehicle would likely be a large flatbed vehicle moving on several parallel train-tracks.  The tricky think is how to do a hand-off to the erector, my thought is that the erector is a pier like extension on the platform and the transporter drives onto this (across a bridge covering the doughnut hole) then the rocket is grasped by the erector then the transporter crouches slightly and drives back along the causeway.  The rocket is then erected and fueled via propellant piped down the underside of the causeway.  Personnel can reach the platform via a small cable-car like booth likewise on the underside of the causeway.

Here is a depth chart of the local waters, http://www.nauticalchartsonline.com/chart/zoom?chart=11301

It looks like you can get 20 km off shore with the water just over 100 ft deep, the main thing to avoid is the Brownsville shipping lane (Brazos Santiago Pass) which is ~10 km from Boca at the shore and the Mexican international water boarder, these two features are running mostly East but do converge slightly, still it looks feasible that a platform might be placed out their.
Title: Re: Where will BFR launch from?
Post by: groundbound on 05/17/2016 03:04 am
The smart money is on the Yorkshire Coast, Northern England.

What? At least I'd get a bloody webcam set up! ;D

I assume you're implying that no one will care if an accident drops stages onto the Dutch or the Germans.  :)

Since I'm not either of those, I'll have to abstain from judgement.
Title: Re: Where will BFR launch from?
Post by: dorkmo on 05/17/2016 05:20 am
Im going to bet $5 that it'll launch/land on a mega ASDSheavyv1.3FT within 1,000 miles of Kiritimati https://en.wikipedia.org/wiki/Kiritimati

and theyll load it in long beach

if its okay i'd like to amend my bet...

it'll launch from one megaASDS launch/land mobile complex and then land on a second megaASDS downrange. they will act as a pair, swapping back and forth to get into launch and landing position.

and the final assembly will take place on the megaASDS in long beach
Title: Re: Where will BFR launch from?
Post by: rumble on 05/17/2016 05:47 am
Wait...  they're not launching from 39A because..?  ISTR it's because of noise concerns for Titusville 20 miles away.  If so, a BFR platform would need to be farther than that from Brownsville by...50%? (I don't know the acoustic dissipation gradient with increasing distance).
...just asking...
Title: Re: Where will BFR launch from?
Post by: dorkmo on 05/17/2016 05:59 am
i was just thinking they could ring the equator with launch/landing sites and theyd never have to transport the stage. or design for rtls.
Title: Re: Where will BFR launch from?
Post by: llanitedave on 05/17/2016 06:04 am
What about a mile long artificial island/causeway with the pad at the end? Means you don't need to load the assembled BFR on any boats - just roll it out there and raise it up. Load passengers after erection.
In an launch rate environment of a launch per week this would be sufficient to warrant the costs of such a civil engineering endeavor. But first is there any close to this as a natural feature?

An artificial island would be too expensive, a massive engineering project. They make sense for Dubai where the water is only a few meters deep. Off the coast of Brownsville is shallow for platforms, but too deep for an artificial island.

A bridge to the platform would be convenient, but the question is would it be cheaper than a barge and crane? The platform would need to be far enough offshore, several kilometers, making a bridge expensive.


There may be some for lease in the South China Sea.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 05/17/2016 02:29 pm
Wait...  they're not launching from 39A because..?  ISTR it's because of noise concerns for Titusville 20 miles away.  If so, a BFR platform would need to be farther than that from Brownsville by...50%? (I don't know the acoustic dissipation gradient with increasing distance).
...just asking...

My understanding is that LC-39 was sized for the Saturn V, and that, among other things, the flame trench is not big enough to handle a BFR -- assuming a BFR of the size we're speculating about, with a liftoff thrust a good 40% or more greater than the Saturn V.

Even NASA, when they considered building the Nova, were planning on launching it from a platform off the coast, not from Merritt Island or the Cape itself.  So, there is history to support LC-39 not being suitable for launchers larger than the Saturn V...
Title: Re: Where will BFR launch from?
Post by: oldAtlas_Eguy on 05/17/2016 03:25 pm
Wait...  they're not launching from 39A because..?  ISTR it's because of noise concerns for Titusville 20 miles away.  If so, a BFR platform would need to be farther than that from Brownsville by...50%? (I don't know the acoustic dissipation gradient with increasing distance).
...just asking...

My understanding is that LC-39 was sized for the Saturn V, and that, among other things, the flame trench is not big enough to handle a BFR -- assuming a BFR of the size we're speculating about, with a liftoff thrust a good 40% or more greater than the Saturn V.

Even NASA, when they considered building the Nova, were planning on launching it from a platform off the coast, not from Merritt Island or the Cape itself.  So, there is history to support LC-39 not being suitable for launchers larger than the Saturn V...
You could still do it you just need to evacuate Merritt Island. In fact if SpaceX took over all the KSC facilities on the Island (no NASA offices would be occupied requiring new buildings off the Island) it could be done giving BFR two pads to launch from. It would be possible to do two launches a week in this case. But would require a complete relocation of almost all NASA personnel away from their current offices.
Title: Re: Where will BFR launch from?
Post by: Ludus on 05/17/2016 05:06 pm
Wait...  they're not launching from 39A because..?  ISTR it's because of noise concerns for Titusville 20 miles away.  If so, a BFR platform would need to be farther than that from Brownsville by...50%? (I don't know the acoustic dissipation gradient with increasing distance).
...just asking...

No, because 39a wasn't built for BFR's projected thrust at liftoff. Rebuilding it would take it out of use for Falcon Heavy and Dragon 2 service to the ISS.
Title: Re: Where will BFR launch from?
Post by: rumble on 05/18/2016 01:20 am
Wait...  they're not launching from 39A because..?  ISTR it's because of noise concerns for Titusville 20 miles away.  If so, a BFR platform would need to be farther than that from Brownsville by...50%? (I don't know the acoustic dissipation gradient with increasing distance).
...just asking...

No, because 39a wasn't built for BFR's projected thrust at liftoff. Rebuilding it would take it out of use for Falcon Heavy and Dragon 2 service to the ISS.
39a was designed for up to?  11M lbf thrust?  (can't remember)  still shy of BFR regardless...

...so it's flame trench strength more than acoustic pressure in Titusville?  I stand corrected.

Edit:  I brought this up thinking acoustic SPL would dictate launch platform distance from Brownsville.

thx
--matt;
Title: Re: Where will BFR launch from?
Post by: TomH on 05/18/2016 01:28 am
Titusville has grown since the Apollo days. The main problem is the acoustics. You can rebuild a flame trench. Replacing a million busted house windows and facing  a million person class-action lawsuit.......that's another issue entirely.
Title: Re: Where will BFR launch from?
Post by: docmordrid on 05/18/2016 02:04 am
Not to mention that a Cleveland disaster level gas explosion near the ground would be the equivalent of a ~2kt tactical nuke in terms of blast. Unhealthy.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 05/18/2016 02:38 am
Wait...  they're not launching from 39A because..?  ISTR it's because of noise concerns for Titusville 20 miles away.  If so, a BFR platform would need to be farther than that from Brownsville by...50%? (I don't know the acoustic dissipation gradient with increasing distance).
...just asking...

No, because 39a wasn't built for BFR's projected thrust at liftoff. Rebuilding it would take it out of use for Falcon Heavy and Dragon 2 service to the ISS.
39a was designed for up to?  11M lbf thrust?  (can't remember)  still shy of BFR regardless...

...so it's flame trench strength more than acoustic pressure in Titusville?  I stand corrected.

Edit:  I brought this up thinking acoustic SPL would dictate launch platform distance from Brownsville.

thx
--matt;

No, LC-39 was sized for the Saturn V -- 7.5 millions lbs of thrust, not 11.  That was Nova, and LC-39 was not sized for Nova.  Had Nova been built, it would have been flown off of an offshore platform, per Rocco Petrone, the guy who set up all of the specifications for LC-39.

It's a flame trench issue, it's  matter of the size of the actual concrete pad, it's a matter of the acoustic energy generated by (in the case of Nova vs. Saturn V) eight F-1 engines vs five... it's a lot of things.

So, no, LC-39 was never, ever considered viable for launching anything larger than the Saturn V.  Really.
Title: Re: Where will BFR launch from?
Post by: Impaler on 05/18/2016 03:34 am
What are the actual physical forces that limit the thrust a pad (not any thing nearby) can handle?  Is it heat, vibration, the shear force of the rocket trying to punch into the ground?  What is the effect of an inadequately sized flame-trench upon launch?  What modification dose a pad physically NEED to be able to handle larger vehicles with more thrust.
Title: Re: Where will BFR launch from?
Post by: TomH on 05/18/2016 09:55 pm
Not to mention that a Cleveland disaster level gas explosion near the ground would be the equivalent of a ~2kt tactical nuke in terms of blast. Unhealthy.

Not really. The total energy release may be equivalent of 2kt, however that chemical energy is released over a period of several seconds. A nuke releases all of the energy in nanoseconds, maybe less, at a temperature many orders of magnitude higher, thus creating a far more devastating shock wave. This is comparing apples to oranges.

While it would be a big explosion, it wouldn't be like a nuke. The pulse from the shock wave is not the same.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/20/2016 06:11 pm
Put the landing pad right by the launch pad so you don't need to truck/barge/whatever the booster back to the launch pad.

Even if the booster barges, the idea was to partly refuel the booster and fly it back to the launch site. So that takes care of the transport problem.

The BFS would probably need to be trucked to the launch site after some refurb, but likely most launches will be propellant for that, so extensive refurb wouldn't be required for all launches, some could return straight to launch site like the booster.

Can't launch from LC39A. Flame trench not built to withstand that level of thrust, besides they filled in one of the two sides of the flame trench (the one facing their big rocket shed) with concrete so it's capable of even less.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 05/20/2016 06:19 pm
Put the landing pad right by the launch pad so you don't need to truck/barge/whatever the booster back to the launch pad.

Even if the booster barges, the idea was to partly refuel the booster and fly it back to the launch site. So that takes care of the transport problem.

The BFS would probably need to be trucked to the launch site after some refurb, but likely most launches will be propellant for that, so extensive refurb wouldn't be required for all launches, some could return straight to launch site like the booster.

Can't launch from LC39A. Flame trench not built to withstand that level of thrust, besides they filled in one of the two sides of the flame trench (the one facing their big rocket shed) with concrete so it's capable of even less.

I really think that Elon's tweet about flying stages back from the barges wasn't really something that SpaceX was seriously looking at doing -- it was an example of Elon being Elon and tossing out a thought as it occurred to him, without it being vetted or seriously studied by his technical people.

Think about it -- we're saying that the large LC-39 pad, designed for a Saturn V, is not big enough to support a BFR launch.  And yet there are still mentions of the concept of re-launching recovered stages from ASDSes.

There is a really big cognitive dissonance in there somewhere.

I really, truly, without any question think that SpaceX will never consider re-launching a stage from an ASDS, be it Falcon or BFR, to "hop" it back to its launch site.  Elon's tweet aside, I sort of think we need to stop mentioning that as a future option.

Especially for the BFR...
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/20/2016 06:30 pm
Put the landing pad right by the launch pad so you don't need to truck/barge/whatever the booster back to the launch pad.

Even if the booster barges, the idea was to partly refuel the booster and fly it back to the launch site. So that takes care of the transport problem.

The BFS would probably need to be trucked to the launch site after some refurb, but likely most launches will be propellant for that, so extensive refurb wouldn't be required for all launches, some could return straight to launch site like the booster.

Can't launch from LC39A. Flame trench not built to withstand that level of thrust, besides they filled in one of the two sides of the flame trench (the one facing their big rocket shed) with concrete so it's capable of even less.

I really think that Elon's tweet about flying stages back from the barges wasn't really something that SpaceX was seriously looking at doing -- it was an example of Elon being Elon and tossing out a thought as it occurred to him, without it being vetted or seriously studied by his technical people.
...
Elon is technical.

Your statement reminds me of this:
https://www.youtube.com/watch?v=uMM0lRfX6YI

So I'd bet money you're wrong. I guarantee SpaceX is seriously looking into it and probably wants to try it.

Doesn't mean they'll actually use it operationally. But you seriously under-sell Elon here.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 05/20/2016 06:48 pm
...I'd bet money you're wrong. I guarantee SpaceX is seriously looking into it and probably wants to try it.

Has the makings of an epic bet, here... :)

Since it's inappropriate to bet money through the forum, we'll have to come up with some other, not-highly-expensive thing to bet with (I'm not a rich man and I'm surviving on disability insurance payouts right now).  But, assuming we can set up a prize agreeable to all, I'd be willing to take that bet... :)
Title: Re: Where will BFR launch from?
Post by: philw1776 on 05/20/2016 07:30 pm
I've won Internet technical bets.
Winner & loser each post signatures for 6 months reflective of win or loss respectively.
OR
Loser stops posting on forum for time = T

Just a few options

/topic
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/20/2016 07:34 pm
I'm betting that SpaceX has seriously considered refueling the landed stages (edit: in the future, perhaps far in the future), if that wasn't clear. I'll buy you a beverage of your choice, value not to exceed $10. Must be redeemed in person, here in Hampton Roads, VA.

But I'd do that even if I won. :)
Title: Re: Where will BFR launch from?
Post by: philw1776 on 05/20/2016 07:36 pm
Put the landing pad right by the launch pad so you don't need to truck/barge/whatever the booster back to the launch pad.

Even if the booster barges, the idea was to partly refuel the booster and fly it back to the launch site. So that takes care of the transport problem.

The BFS would probably need to be trucked to the launch site after some refurb, but likely most launches will be propellant for that, so extensive refurb wouldn't be required for all launches, some could return straight to launch site like the booster.

Can't launch from LC39A. Flame trench not built to withstand that level of thrust, besides they filled in one of the two sides of the flame trench (the one facing their big rocket shed) with concrete so it's capable of even less.

I really think that Elon's tweet about flying stages back from the barges wasn't really something that SpaceX was seriously looking at doing -- it was an example of Elon being Elon and tossing out a thought as it occurred to him, without it being vetted or seriously studied by his technical people.

Think about it -- we're saying that the large LC-39 pad, designed for a Saturn V, is not big enough to support a BFR launch.  And yet there are still mentions of the concept of re-launching recovered stages from ASDSes.

There is a really big cognitive dissonance in there somewhere.

I really, truly, without any question think that SpaceX will never consider re-launching a stage from an ASDS, be it Falcon or BFR, to "hop" it back to its launch site.  Elon's tweet aside, I sort of think we need to stop mentioning that as a future option.

Especially for the BFR...

Dunno about considering it, but I do agree they won't do it.
One helluva big pad 39A type ASDS structure needed.  Then maybe not, because not even half the engines need fire for the hop back with no upper stage or full 1st stage propellant.
I DO think BFR flights will use an ASDS because they can carry more propellant to LEO for the many re-fueling trips a BFS needs.  A couple barges rotating BFRs back to wherever where they're offloaded and preped for return to rotation.
BFS will RTLS for re-flight.  Why not?
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 05/20/2016 07:47 pm
I'm betting that SpaceX has seriously considered refueling the landed stages, if that wasn't clear. I'll buy you a beverage of your choice, value not to exceed $10. Must be redeemed in person, here in Hampton Roads, VA.

But I'd do that even if I won. :)

You're on, same arrangements.  If and when you would visit me here in Minneapolis.  And same deal, I'd buy a round even if I won.  :)

Of course, proof either way may be hard to come by, but if I am ever proven wrong, I'll be proud to admit it...  :)
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/20/2016 07:47 pm
Consider this:

SpaceX will have to launch BFS from Mars, with about as much take-off thrust as a BFR would need for a return-to-launchsite-from-barge trajectory. The launch pad on Mars will need to be very rudimentary, comparable to what you could do for a barge.

DC-X was just a concrete pad:
https://www.youtube.com/watch?v=wv9n9Casp1o

And so was F9R-dev1 and Grasshopper.

As far as LC-39A being too small for BFR, that's for a different reason. The flame trench is simply not designed for it.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/20/2016 07:48 pm
I'm betting that SpaceX has seriously considered refueling the landed stages, if that wasn't clear. I'll buy you a beverage of your choice, value not to exceed $10. Must be redeemed in person, here in Hampton Roads, VA.

But I'd do that even if I won. :)

You're on, same arrangements.  If and when you would visit me here in Minneapolis.  And same deal, I'd buy a round even if I won.  :)

Of course, proof either way may be hard to come by, but if I am ever proven wrong, I'll be proud to admit it...  :)
Hey, I used to live in Minneapolis, so I go by that area quite often. I'm from Minnesota.
Title: Re: Where will BFR launch from?
Post by: Hyperion5 on 05/21/2016 03:20 pm
Put the landing pad right by the launch pad so you don't need to truck/barge/whatever the booster back to the launch pad.

Even if the booster barges, the idea was to partly refuel the booster and fly it back to the launch site. So that takes care of the transport problem.

The BFS would probably need to be trucked to the launch site after some refurb, but likely most launches will be propellant for that, so extensive refurb wouldn't be required for all launches, some could return straight to launch site like the booster.

Can't launch from LC39A. Flame trench not built to withstand that level of thrust, besides they filled in one of the two sides of the flame trench (the one facing their big rocket shed) with concrete so it's capable of even less.

So if they can't launch from 39-A or 39-B, is there a realistic chance they can fit a BFR pad or 2 at KSC without completely moving all of the NASA offices?  Also, if they did have a pad at KSC, could they find room for a factory and test stand there outside the BFR pad blast radius?  I'm confident they would be able find a landing pad, but am not so sanguine about testing such a monster at KSC.

To me it seems like they would want a standalone area for everything BFR-related to cut down on logistics issues and launch congestion.  Imagine Spacex needed to launch a BFR tomorrow in order to make their Mars launch window.  However at CCAFS the Air Force has given launch priority to a Falcon Heavy or Vulcan launch of a large spy satellite.  Launch congestion like that is something they need to avoid.  Arguably Brownsville would be better for avoiding congestion, but it still would interfere with commercial operations.  Plus even if you did do ocean platform launches to avoid restrictions I'm not sure many platforms could last long with 2X the thrust of a Saturn V blasting through them regularly.  You would also need to have an off-shore test platform, landing pad and cranes capable of moving a multi-hundred tonne object up from barges. 

A more ideal setup would be an island where you could build, test, launch, land and transport such a rocket safely while not being so isolated that finding employees is difficult.  The best match I found for that criterion list is Isla de Vieques, Puerto Rico, USA.  It's got a great launch spot on its eastern edge, it's large enough to also support a factory, test stand and landing pads, is only 30 minutes by boat from the main island's largest city, has schools, police, an airport and a port, and there are plenty of gaps between islands to its east to allow launches.  It has its faults-its eastern half was once a bombing range, it cannot beat KSC for attracting people, and there is no previously existing infrastructure.  However in terms of convenience and avoiding launch congestion it bests both KSC and Brownsville, and arguably is just as cost competitive as Brownsville.
Title: Re: Where will BFR launch from?
Post by: oldAtlas_Eguy on 05/21/2016 05:51 pm
A good spot and one I think that SpaceX was already looking at for F9/FH. For F9/FH the problem was getting the stages onto the island. But if the stage manufacturing/assembly plant was co-located and only components (engines mostly) were shipped in easy container size that can be sealed and internally controlled climate the cons are not as bad for BFR/MCT as it was for F9/FH.

Having a large area that is unoccupied due to hazards would be great. It would just require a large enough cleared area so that any un-exploded ordnance exploding would not be of a concern to operations. The BFR vibrations may even clear an additional range of space around the pad or pads by vibration inducing ordnance exploding.

A BTW here is that VAFB south base where most of the pads are, used to be a Navy shore bombardment test range. Which is why the whole area was always a government controlled area and very large.

The additional item is that the MCT cargo operations is more likely to be at the pad of one of containers ready to load on the MCT arriving via cargo plane with little processing if any other than loading, latching and hookups for power, comm/control, and environmental. MCT cargo operations will be more like loading a cargo aircraft. Making the payload processing for MCT cargo would be dispersed to the sources of the cargo instead of being at the pad.
Title: Re: Where will BFR launch from?
Post by: DAZ on 05/21/2016 08:54 pm
I do believe that Isla de Vieques, Puerto Rico was the island that the locals after a considerable effort and protests managed to kick the United States Navy off of because they were making too much noise.  It would seem very unlikely that the locals after spending so much effort would welcome an even more disruptive organization as SpaceX launching the largest rocket ever built.
Title: Re: Where will BFR launch from?
Post by: Hyperion5 on 05/22/2016 03:32 am
I do believe that Isla de Vieques, Puerto Rico was the island that the locals after a considerable effort and protests managed to kick the United States Navy off of because they were making too much noise.  It would seem very unlikely that the locals after spending so much effort would welcome an even more disruptive organization as SpaceX launching the largest rocket ever built.

There was a lot more to the issue than just noise, and the level of use by the Navy would be far higher than anything Spacex could manage: "Vieques was bombed an average of 180 days per year. In 1998, the last year before protests interrupted maneuvers, the Navy dropped 23,000 bombs on the island, the majority of which contained explosives."-McCaffrey, Katherine T. (2006). “The Battle for Vieques’ Future.” CENTRO Journal. Vol 18, no. 1: 125-147.  According to the Navy, in six decades about 5 million pounds (2,000 t) of ordnance was dropped on Vieques every year. Ordnance included toxic compounds and elements such as arsenic, lead, mercury, cadmium, depleted uranium and napalm, and a fiberglass-like substance. All of this bombing with toxic element-laced bombs was correlated with a 27% higher rate of cancer than Puerto Rican mainlanders and a study from 1999 that tested hair samples from Vieques residents showed that 69% were contaminated with cadmium and arsenic, and 34% had toxic levels of mercury.  The infant mortality rate on the island in 2004, the year after the bombing stopped, was 55% higher than in mainland Puerto Rico.  Against this backdrop of real damage being inflicted on Viequenses, a civilian Navy employee was killed by unexploded ordnance in 1999, triggering the surge in protests that eventually led to the end of the Navy's bombings on Vieques. 

Now compare that list of horrific issues with the BFR.  Spacex would be very lucky to manage anywhere close to 180 days of rocket testing firings & launches on Vieques.  The BFR would not contain the toxic chemicals that caused such a political uproar for the Navy.  It would bring high-paying jobs onto an economically depressed island and territory right when they need them.  It would also draw tens of thousands of tourists to the island for launches.  Yes, it's loud and it's large, but it's far safer for Viequenses than what came before it.  So while it may have some political issues, I don't think they're anywhere near what drove the Navy off Vieques.  Lest we forget, there are also serious issues with KSC & Brownsville as BFR launch sites.  Robotbeat rightly pointed out none of the major pads at KSC can handle a BFR and building a new one might entail moving NASA facilities.  Meanwhile Brownsville residents made complaints about the trucks carrying dirt to the Falcon 9/FH launch site being dangerous to their safety (http://valleycentral.com/news/local/spacex-construction-causing-problems-for-surrounding-residents).  One can only imagine the political reaction to a BFR pad in that community if a few truck accidents are causing this much consternation.  The alternative of an off-shore pad means a lot more logistical hassles and might even require some negotiation with the Mexican government. 

So sure, Vieques isn't perfect, but it definitely should be on Spacex's prospective BFR site list. 
Title: Re: Where will BFR launch from?
Post by: docmordrid on 05/22/2016 06:32 am
There's also Camden County, Georgia, which was eliminated when Boca Chica was selected.

They're going through the EIS process for a vertical launch spaceport around the old Thiokol site,  and the scoping report was released May 5.

Satellite map.... (http://matchbin-assets.s3.amazonaws.com/public/sites/2777/assets/6182_spaceport_map.jpg)

Scoping Report....(PDF) (http://www.faa.gov/about/office_org/headquarters_offices/ast/environmental/nepa_docs/review/documents_progress/camden_spaceport/media/Spaceport_Camden_EIS_Scoping_Summary_Report.pdf)
Title: Re: Where will BFR launch from?
Post by: cartman on 05/22/2016 01:54 pm
I like the idea of a having a Floating Mobile Launcher Platform that is sent to a designated launching spot ~10 miles away from shore. That spot has underwater legs that reach a few meters under the surface, so that the FMLP can sit on top by lowering itself when it fills its tanks with water. There the rocket is fueled and launched, and the FMLP returns to the facility.

The first stage lands on a larger ASDS and is sent back either on top of the ASDS or on a specialized ship. The second stage lands on land, close to the FMLP facility, where it is prepared and mated to a first stage on a FMLP. The facility is next to the water and has a few hundred meters of canal under a roof. Adding FMLPs and first stage return ships can make this scale to support a very large launch rate. Also this can work anywhere, and does not have to be close to the BFR factory.
Title: Re: Where will BFR launch from?
Post by: philw1776 on 05/22/2016 02:22 pm
Both  Camden County, Georgia & Vieques, Puerto Rico have overfly issues.  There's Cumberland Island park in the Georgia path and numerous tourist & residential island in the possible path of a failed Vieques BFR overflight.
Don't know if these sites would be easy to attract the skilled engineering & manufacturing workforce needed to design, build & fly BFRs.  SX culture has development engineers co-located with manufacturing, a culture as a new product developer I heartily endorse.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 05/22/2016 03:57 pm
I find it interesting that the Camden, GA scoping document clearly specifies SpaceX operations,  stating there would be "up to 12" launches and landings per year from the site (which seems low for the BFR architectures we've speculated about).  The various people listed who were to be attending the public meeting, though, represented all of the various polities (from the local mayor all the way up to a representative of one of the U.S. Senators from Georgia) and various media representatives -- but no one to answer questions from SpaceX.

Seems odd, somehow, that you would have what amount to public hearings on the environmental impact from a spaceport in the area, without any direct input from the folks who would be building the facilities and flying the rockets...  ???
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/22/2016 07:08 pm
I do believe that Isla de Vieques, Puerto Rico was the island that the locals after a considerable effort and protests managed to kick the United States Navy off of because they were making too much noise.  It would seem very unlikely that the locals after spending so much effort would welcome an even more disruptive organization as SpaceX launching the largest rocket ever built.

There was a lot more to the issue than just noise, and the level of use by the Navy would be far higher than anything Spacex could manage: "Vieques was bombed an average of 180 days per year. In 1998, the last year before protests interrupted maneuvers, the Navy dropped 23,000 bombs on the island, the majority of which contained explosives."-McCaffrey, Katherine T. (2006). “The Battle for Vieques’ Future.” CENTRO Journal. Vol 18, no. 1: 125-147.  According to the Navy, in six decades about 5 million pounds (2,000 t) of ordnance was dropped on Vieques every year. Ordnance included toxic compounds and elements such as arsenic, lead, mercury, cadmium, depleted uranium and napalm, and a fiberglass-like substance. All of this bombing with toxic element-laced bombs was correlated with a 27% higher rate of cancer than Puerto Rican mainlanders and a study from 1999 that tested hair samples from Vieques residents showed that 69% were contaminated with cadmium and arsenic, and 34% had toxic levels of mercury.  The infant mortality rate on the island in 2004, the year after the bombing stopped, was 55% higher than in mainland Puerto Rico.  Against this backdrop of real damage being inflicted on Viequenses, a civilian Navy employee was killed by unexploded ordnance in 1999, triggering the surge in protests that eventually led to the end of the Navy's bombings on Vieques. 

Now compare that list of horrific issues with the BFR.  Spacex would be very lucky to manage anywhere close to 180 days of rocket testing firings & launches on Vieques.  The BFR would not contain the toxic chemicals that caused such a political uproar for the Navy.  It would bring high-paying jobs onto an economically depressed island and territory right when they need them.  It would also draw tens of thousands of tourists to the island for launches.  Yes, it's loud and it's large, but it's far safer for Viequenses than what came before it.  So while it may have some political issues, I don't think they're anywhere near what drove the Navy off Vieques.  Lest we forget, there are also serious issues with KSC & Brownsville as BFR launch sites.  Robotbeat rightly pointed out none of the major pads at KSC can handle a BFR and building a new one might entail moving NASA facilities.  Meanwhile Brownsville residents made complaints about the trucks carrying dirt to the Falcon 9/FH launch site being dangerous to their safety (http://valleycentral.com/news/local/spacex-construction-causing-problems-for-surrounding-residents).  One can only imagine the political reaction to a BFR pad in that community if a few truck accidents are causing this much consternation.  The alternative of an off-shore pad means a lot more logistical hassles and might even require some negotiation with the Mexican government. 

So sure, Vieques isn't perfect, but it definitely should be on Spacex's prospective BFR site list.
Very, very good points, but if SpaceX is going to build a new spaceport outside of the continental US for BFR, they would be aiming for very high launch rates.

To meet SpaceX's long-term goals (80,000 people to Mars plus a LOT of cargo), the site has to be capable of something on the order of one launch every hour (!). Even with multiple sites, you're looking at every few hours.

Pick a site that could someday be capable of that launch rate (with multiple pads) or just build a launch site in the continental US.
Title: Re: Where will BFR launch from?
Post by: cartman on 05/22/2016 09:57 pm
Large launch rates make sea launch a necessity. I don't think there are communities that will accept the noise and hassle of frequent launches at the scale of the BFR.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/22/2016 11:58 pm
Large launch rates make sea launch a necessity. I don't think there are communities that will accept the noise and hassle of frequent launches at the scale of the BFR.
Literal sea launch isn't required. Building a platform or finding a small island works, too.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 05/23/2016 12:39 am
...If SpaceX is going to build a new spaceport outside of the continental US for BFR, they would be aiming for very high launch rates.

To meet SpaceX's long-term goals (80,000 people to Mars plus a LOT of cargo), the site has to be capable of something on the order of one launch every hour (!). Even with multiple sites, you're looking at every few hours.

Pick a site that could someday be capable of that launch rate (with multiple pads) or just build a launch site in the continental US.

Very good point yourself, RB.  Makes you think that SpaceX may well be looking at setting up multiple launch sites for the BFRs.  I seriously doubt we'll ever see launch rates of one an hour, even when adding up all of the launch sites.  But with, say, eight or ten total BFR launch sites, you could see a launch every few days from each site.

And while I understand what you're saying, I really don't think, as I said above, that we'll ever see launches-on-the-hour.  Any architecture that needs that many launches is gonna end up so expensive, even with extensive re-use, as to be unsupportable.  Remember, while Musk may want to get a million people to Mars, he's never said they all need to get there by 2030... ;)

The likely launch rate of one every few days per site, though, really strongly argues for developing all of the BFR launch sites (and profiles) for RTLS stage recoveries only.  At even that kind of flight rate, you'd need dozens of ASDSes to keep up with downrange recoveries.  Also, don't forget that you would see launch salvos scheduled around the various optimal Mars launch opportunities (both conjunction and opposition), with stand-downs of many months between heavy salvos.  So, again, likely not looking at continuous, day-in, day-out launch operations in support of the Mars colony.  There will be downtimes.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/23/2016 01:09 am
Why not a launch per hour? Some busy airports with multiple runways do a take-off every 30 seconds. A launch per hour is roughly what SpaceX requires for its ambitions.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 05/23/2016 01:17 am
Why not a launch per hour? Some busy airports with multiple runways do a take-off every 30 seconds. A launch per hour is roughly what SpaceX requires for its ambitions.

I guess my apprehension of how hard it is to let an airliner take off vs. how hard it is to launch a rocket the size of a BFR is such that you'll never be able to reliably compare the two.  That's just me, though, YMMV... :)
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/23/2016 02:39 am
Why not a launch per hour? Some busy airports with multiple runways do a take-off every 30 seconds. A launch per hour is roughly what SpaceX requires for its ambitions.

I guess my apprehension of how hard it is to let an airliner take off vs. how hard it is to launch a rocket the size of a BFR is such that you'll never be able to reliably compare the two.  That's just me, though, YMMV... :)
I don't see any difference from a physics perspective that couldn't, in principle, be engineered-away (i.e. sufficient water sound suppression, active cooling of launch structures and/or construction using high-temperature materials, etc).
Title: Re: Where will BFR launch from?
Post by: Impaler on 05/23/2016 06:17 am
Multiple pads per launch site and multiple launch sites (even multiple countries with multiple sites), is more reasonable then saying that much traffic will go through one space port.  And even if that was the case their is no reason to think the first launch site is the one that would be scaled up to that size. 

Musk loves scaling things up but he has consistently searched out cheap locations to place his businesses and with each expansion has examined a new crop of potential locations, that keeps the localities/municipalities eager to offer incentives and not take him for granted.

Their are also technical reasons this is unlikely, that kind of throughput would require a whole master-planned facility designed from the ground up (just like a modern airport), but that requires that they know how to design such a thing which will require that every aspect of the launch process both logistical and human has become a routine thing something that will take years of operation to figure out.  A battery Giga-factory is doing a comparatively rote and well understood task and is thus ready for scaling up, reusing a rocket is not at all rote.

Basically you have to crawl before you can walk and you have to walk before you run.  You need a shoe (launch facility) appropriate to each phase, trying to wear running shoes when crawling is going to hold you back.
Title: Re: Where will BFR launch from?
Post by: Semmel on 05/23/2016 06:57 am
There will probably not more than a launch every few days per site. The analogy to airports is misleading. A flight takes a few hours at most. And the preparation time a person needs for each flight scales roughly linearly with flight time. The fact that airports have such a high througput as they have today is also a result of our practice doing it. We simply fly do much that we are really good at it.
For space launches, that is different. We don't have the practice and we don't arrive as fast. Any destination in space is at least a few days away. Mars even a few months. The amount of preparation for such a trip will likewise be very long.
Think of it that way: to take a ride on a rocket to space compares to taking a flight in a plane roughly in the same way a flight  in a plane compares to riding a car. Both in preparation time and complexity.
Therefore, I don't think rocket flights will ever be similar to plane flights. As a result, launch sites will never operate like airports.
Title: Re: Where will BFR launch from?
Post by: pobermanns on 05/23/2016 08:50 am
The best match I found for that criterion list is Isla de Vieques, Puerto Rico, USA.

The US Navy got kicked off of Vieques back in the 1970's, because of the noise from the bombing and shelling. I seriously doubt that the locals will welcome launches of the biggest/loudest rocket in history. :(

EDIT: My mistake - It was Culebra Island that the USN had to leave in 1975, but for the same reasons as Vieques years later.
Title: Re: Where will BFR launch from?
Post by: The Amazing Catstronaut on 05/23/2016 09:13 am
There will probably not more than a launch every few days per site. The analogy to airports is misleading. A flight takes a few hours at most. And the preparation time a person needs for each flight scales roughly linearly with flight time. The fact that airports have such a high througput as they have today is also a result of our practice doing it. We simply fly do much that we are really good at it.
For space launches, that is different. We don't have the practice and we don't arrive as fast. Any destination in space is at least a few days away. Mars even a few months. The amount of preparation for such a trip will likewise be very long.
Think of it that way: to take a ride on a rocket to space compares to taking a flight in a plane roughly in the same way a flight  in a plane compares to riding a car. Both in preparation time and complexity.
Therefore, I don't think rocket flights will ever be similar to plane flights. As a result, launch sites will never operate like airports.

A better analogy is a seaport. The BFS is both a container ship and an ocean liner, if you view deep space to be analogous to an ocean. Spaceports will become more airport-esque once we have people making multiple cycles to and from Mars in one lifetime (I.E: people moving back and forth from Mars in the same way people move from one Earth property to the next at various points in their lives. People cope with house moving processes that can take up to a good few months if the circumstances are unpermissive, longer if you have to buy and install fresh furniture and appliances or do any cosmetic or structural work on the residence). Once mars is no longer an outpost, I can see it becoming more regular.

For the need for multiple airport-like launch facilities, I'd be expecting multiple destinations (not just mars), and new propulsion technology. I'm sure both of those prerequisite factors will happen at some point, but they're too far out for now to speculate.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/23/2016 03:19 pm
There will probably not more than a launch every few days per site. The analogy to airports is misleading. A flight takes a few hours at most. And the preparation time a person needs for each flight scales roughly linearly with flight time. The fact that airports have such a high througput as they have today is also a result of our practice doing it. We simply fly do much that we are really good at it.
For space launches, that is different. We don't have the practice and we don't arrive as fast. Any destination in space is at least a few days away. Mars even a few months. The amount of preparation for such a trip will likewise be very long.
Think of it that way: to take a ride on a rocket to space compares to taking a flight in a plane roughly in the same way a flight  in a plane compares to riding a car. Both in preparation time and complexity.
Therefore, I don't think rocket flights will ever be similar to plane flights. As a result, launch sites will never operate like airports.
No.

Most BFR flights will be for launching propellant to orbit. Your destination is only minutes or hours away. The only "preparation" the cargo needs is to be pumped into tanks.

If you're going to be launching 80,000 people to Mars per year plus a bunch more flights for cargo, then launching every hour or every few hours is a requirement. You're not going to have dozens of launch sites. Dozens of launch pads, sure.

Yes, this will take a while to get up there, but there's NO technical reason this can't be done.

Prep time can be reduced. Your initial destination is very close.

Additionally, more BFSes will need to be built than BFR boosters. Each booster will send multiple BFSes per synod (perhaps 10 or more). The BFSes themselves will be the only part of the rocket making the long trip. The flight time for the boosters will only be a few minutes.

BFSes would be pre-processed in another location (except perhaps for ones launching cargo or propellant only). BFRs will be made for fast turnaround.
Title: Re: Where will BFR launch from?
Post by: oldAtlas_Eguy on 05/23/2016 04:02 pm
To put some bounds on launch rate for BFR:
1) to launch 20 cargo and 2 crew flights in 1 synod to Mars
2) 6 tanker launches per each Mars MCT
3) total launches per synod 154 launch rate once every 5 days
5) yearly cost at $60M per launch + $100M for the MCT vehicle that heads to Mars (this vehicle may or may not return in more than 4 years so its total cost is sunk at first or its refurbishment costs will be high) = $5,3B/yr
6) yearly cost at $40M per launch + $100M for the MCT vehicle that heads to Mars (this vehicle may or may not return in more than 4 years so its total cost is sunk at first or its refurbishment costs will be high) = $3.9B/yr
7) yearly cost at $30M per launch + $100M for the MCT vehicle that heads to Mars (this vehicle may or may not return in more than 4 years so its total cost is sunk at first or its refurbishment costs will be high) = $3.2B/yr
Title: Re: Where will BFR launch from?
Post by: Ludus on 05/23/2016 04:08 pm
If it's someplace like Vieques the timeline and price list is somewhat longer than building it at or off the cape or even Brownsville where most support infrastructure is already in place. Vieques appears to need a port and runway built before major construction on a factory and launchpad could start. It would need a new power plant, probably a desalination plant, roads, a pretty long expensive list of stuff.
Title: Re: Where will BFR launch from?
Post by: Semmel on 05/23/2016 04:11 pm
There will probably not more than a launch every few days per site. The analogy to airports is misleading. A flight takes a few hours at most. And the preparation time a person needs for each flight scales roughly linearly with flight time. The fact that airports have such a high througput as they have today is also a result of our practice doing it. We simply fly do much that we are really good at it.
For space launches, that is different. We don't have the practice and we don't arrive as fast. Any destination in space is at least a few days away. Mars even a few months. The amount of preparation for such a trip will likewise be very long.
Think of it that way: to take a ride on a rocket to space compares to taking a flight in a plane roughly in the same way a flight  in a plane compares to riding a car. Both in preparation time and complexity.
Therefore, I don't think rocket flights will ever be similar to plane flights. As a result, launch sites will never operate like airports.
No.

Most BFR flights will be for launching propellant to orbit. Your destination is only minutes or hours away. The only "preparation" the cargo needs is to be pumped into tanks.

If you're going to be launching 80,000 people to Mars per year plus a bunch more flights for cargo, then launching every hour or every few hours is a requirement. You're not going to have dozens of launch sites. Dozens of launch pads, sure.

Yes, this will take a while to get up there, but there's NO technical reason this can't be done.

Prep time can be reduced. Your initial destination is very close.

Additionally, more BFSes will need to be built than BFR boosters. Each booster will send multiple BFSes per synod (perhaps 10 or more). The BFSes themselves will be the only part of the rocket making the long trip. The flight time for the boosters will only be a few minutes.

BFSes would be pre-processed in another location (except perhaps for ones launching cargo or propellant only). BFRs will be made for fast turnaround.

Please note how I did not say "It cant be done". Note also, that I did not address the technical aspect at all.  Its not about the booster, its about its cargo. i.e. humans. From a passenger point of view, flying rockets is a magnitude more difficult than flying airplanes which is in turn a magnitude more difficult than driving a car. As a passenger.

In a car, you just hop in and rive or let your self be driven. Its simple.

In an airplane you have to go through customs, you have to book a ticket (usually well in advance) you have to think about your clothes at the destination because you are far away from home, etc.

If you hop into a rocket that goes to Mars or the moon or even a station in orbit, you have a complete set of different problems and preparations to do. Its NOT as simple as hopping onto a plane. As a consequence, there will not be a demand for rocket flights as there is for planes. And as a consequence of that, the entire process will be more difficult and complex.

The 80.000 figure you quote so frequently is so far into the future that we dont really know how this will come about if at all. Imagine a flight enthusiast states in 1916 that flying planes in 2016 will be similar to riding trains in 1916. And then compare that view with how it actually works today. This gives you an idea how wrong our current view of the future of space flight is.

I think that imagining human space flight in the future to be similar to human air flight today is fundamentally flawed and it should not guide is how to operate/select launch sites. The selection of launch sites need to make sense today. We might be able to extrapolate 10 to 20 years into the future but not much more. For all we know, BFS and BFR is not the solution to make the 80.000 people to Mars per year a reality.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/23/2016 04:17 pm
The customs and everything would be somewhere else. The BFS carrying crew would likely be outfitted off-site well before launch.

Remember, we're dealing with a two-stage vehicle, here, with one part (the first stage) being reused far more often. And the vast majority of the launches wouldn't contain people.

As far as BFR not being the solution for 80k/year to Mars, that's plain false. It's the only reason something as big as BFR is required. If you just wanted to send a few people to Mars or establish a small base, then FH would be just fine, perhaps with a reusable/refuelable Raptor upper stage that could land 20 tons or so at a time.

BFR/BFS is ONLY required for this massive scale. It simply is not required otherwise and would frankly be a waste of money.

And how "far in the future" those launch rates are depends on what site you pick. If you pick something not capable of high launch rates, of course those launch rates are necessarily further in the future than might be possible if you picked a site capable of high launch rates.

BFR doesn't make sense unless you have high launch rates (heck, ANY fully reusable launch vehicle doesn't make sense except for high launch rates). Stick with something more FH-sized if you aren't planning to field such a capability except in the distant future.


With BFR, people need to take SpaceX's ambitions at their word. Doesn't mean you have to think they'll actually do it or that they have the resources to do it, but they're not going to intentionally pick a site that precludes their meeting their goals. TAKE THEM SERIOUSLY.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/23/2016 04:38 pm
If you can only do a launch every few days, that means you're limited to like 100 launches per year per launch site. That's marginal for a fully reusable vehicle. That's more like a MINIMUM viable launch rate than what you would want for a maximum.

If BFR's main launch site is limited to just 100 flights per year, forget it! Stick with a smaller vehicle that you can launch more often.
Title: Re: Where will BFR launch from?
Post by: RedLineTrain on 05/23/2016 05:20 pm
It looks like Camden County, Georgia is no better or worse than Brownsville regarding proximity of civilization for a land-based BFR launch -- roughly five miles away.

Seems awful close to be shooting off a rocket with two times the sea level thrust of the Saturn V.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/23/2016 05:57 pm
It looks like Camden County, Georgia is no better or worse than Brownsville regarding proximity of civilization for a land-based BFR launch -- roughly five miles away.

Seems awful close to be shooting off a rocket with two times the sea level thrust of the Saturn V.
More like 10km.

If that isn't enough:

You could build a platform a few miles out to sea with a causeway. The ocean is very shallow over there, like 10-25m deep. Heck, if you were to have a large vessel, you'd need to dredge out there anyway. Might as well put the dredging spoils to use!

You could either dredge an actual causeway and island or build a causeway and an elevated platform. Cost for both may be about the same. It may come down to upkeep and/or environmental footprint. For a causeway of about 10km long, it may cost $100-200 million or so. That's like a national security launch on a Falcon Heavy. Maybe a similar amount for a small island big enough for a landing pad and a launch pad and transport between the two and a jig for integrating a BFR to a BFS.

10-20km out to sea is probably far enough away from civilization. Boats could go underneath the causeway near shore even during a launch.
Title: Re: Where will BFR launch from?
Post by: RedLineTrain on 05/23/2016 06:07 pm
Robotbeat:  Where are you measuring from and to?

In Camden County:  I am measuring from Jessie's Lane off of Union Carbide Road to the launch pad. 

In Brownsville:  I am measuring from the tip of South Padre Island to the launch pad.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/23/2016 06:10 pm
Robotbeat:  Where are you measuring from and to?

In Camden County:  I am measuring from Jessie's Lane off of Union Carbide Road to the launch pad. 

In Brownsville:  I am measuring from the tip of South Padre Island to the launch pad.
Fair enough. I was going by population, but your measurement is good, too.
Title: Re: Where will BFR launch from?
Post by: Arb on 05/23/2016 06:29 pm
...the MCT vehicle that heads to Mars (this vehicle may or may not return in more than 4 years...
What did you mean by this?

Sounds like you're not expecting MCTs to return till the synod after they depart earth. But Musk has unequivocally stated he wants them back in the same synod, because economics.
Title: Re: Where will BFR launch from?
Post by: RonM on 05/23/2016 08:18 pm
It looks like Camden County, Georgia is no better or worse than Brownsville regarding proximity of civilization for a land-based BFR launch -- roughly five miles away.

Seems awful close to be shooting off a rocket with two times the sea level thrust of the Saturn V.

Both are good for F9 and FH. BFR would be too close.

If that isn't enough:

You could build a platform a few miles out to sea with a causeway. The ocean is very shallow over there, like 10-25m deep. Heck, if you were to have a large vessel, you'd need to dredge out there anyway. Might as well put the dredging spoils to use!

You could either dredge an actual causeway and island or build a causeway and an elevated platform. Cost for both may be about the same. It may come down to upkeep and/or environmental footprint. For a causeway of about 10km long, it may cost $100-200 million or so. That's like a national security launch on a Falcon Heavy. Maybe a similar amount for a small island big enough for a landing pad and a launch pad and transport between the two and a jig for integrating a BFR to a BFS.

10-20km out to sea is probably far enough away from civilization. Boats could go underneath the causeway near shore even during a launch.

Dredging would be expensive because of the amount of dirt needed (10-25m would take a lot of fill), environmental issues, building on newly deposited unstable ground, etc. Platform and bridge would be the way to go.
Title: Re: Where will BFR launch from?
Post by: Impaler on 05/23/2016 09:58 pm
You're not going to have dozens of launch sites. Dozens of launch pads, sure.

Their is no logical basis for this statement, no matter what your desired total launches per unit of time is their is no reason to group them all from one space-port, and many reasons not too. 

Might a BFR launch from EARTH every 5 minutes, sure, a plane probably takes off from the surface of the Earth every second but not all from the same airport.

Multiple space-ports reduce the likely-hood that catastrophic events both natural and man-made destroys, damages or even delays the launching process.  Fewer vehicles transiting through the same air-space make collisions less likely.

If your logic is that all BFR's are manufactured at the launch site and that their will be one manufacturing site and THUS one launch site then this is flawed for two reason, first launching from the factory location for a maiden flight to a space-port is very reasonable and likely just like Boeing planes out of a factory.  Second at the scale of flights your talking about were easily into the realm where more then one manufacturing site is reasonable, and note that manufacturing here is likely to just be the installations of engines which have been sent from Hawthorn.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/24/2016 12:14 am
You're not going to have dozens of launch sites. Dozens of launch pads, sure.

Their is no logical basis for this statement, no matter what your desired total launches per unit of time is their is no reason to group them all from one space-port, and many reasons not too.  ...
Yeah, there is. One or a small single digit number. You'll have much lower cost that way since there will be more economies of scale and less duplication. On Earth, we have a lot of airports, but that's because airports are used for transportation from one place or another.

How many large airports does Atlanta have?

I seriously don't see any good reason to have lots of spaceports. Maybe two or three BFR launch sites so you can hit the different orbits, but other than that, you're really much better off keeping the number down. Additionally, if BFR is only used for beyond-LEO, then you only need a single launch site anyway.

I really don't think in-air collisions is a realistic risk. An airport like Atlanta is able to cope with two orders of magnitude greater number of aircraft per unit time without this being a big risk. Also, the stages will be robotic and thus carefully controlled to prevent any such thing.

So one major launch site or 3 major launch sites, you're still looking at a small number and thus a very high per-site launch rate. There's no way around that without exploding your overhead costs.

And just because 80,000 people per year is an insanely high number compared to current thinking, the costs can NOT be significantly higher than current costs. $500k/passenger*80k passengers/year = $40 billion, that's only twice NASA's budget and still less than the DoD space budget. Cost control will be essential to making this all work. Otherwise it's impossible.
Title: Re: Where will BFR launch from?
Post by: sghill on 05/24/2016 02:16 am
If it's someplace like Vieques the timeline and price list is somewhat longer than building it at or off the cape or even Brownsville where most support infrastructure is already in place. Vieques appears to need a port and runway built before major construction on a factory and launchpad could start. It would need a new power plant, probably a desalination plant, roads, a pretty long expensive list of stuff.

I like PR as a launch site, but it will NOT be in Vieques.  The locals have decades of violent protest history against big military and industrial projects.  The anti-development crowd would make enough noise to kill this before it ever got out of the planning commission. And SpaceX has a history of following incentives dollars-which PR definitely does not have right now.

https://www.youtube.com/watch?v=RNGH-3KnQfw

Silly as it sounds, I'm sticking with my raised causeway offshore near Galveston or Houston as the site. TX DOT has the money to build one, TX has the infrastructure to support it,  and TX government has the incentives and motivation to lure it.
Title: Re: Where will BFR launch from?
Post by: bstrong on 05/24/2016 02:29 am
The problem with a launch platform in the Gulf (or off the Cape) is that a big hurricane could put you out of commission for a long time.

On a related note, redundancy in the event of natural disaster is why you want more than one launch site. You don't want a bad hurricane in the Gulf to mean that Mars doesn't get resupplied this window.
Title: Re: Where will BFR launch from?
Post by: Hyperion5 on 05/24/2016 03:08 am
If it's someplace like Vieques the timeline and price list is somewhat longer than building it at or off the cape or even Brownsville where most support infrastructure is already in place. Vieques appears to need a port and runway built before major construction on a factory and launchpad could start. It would need a new power plant, probably a desalination plant, roads, a pretty long expensive list of stuff.

Well it will definitely require more support infrastructure than the Cape, but you can make a strong argument that the requirement for off-shore launch at Brownsville means its support infrastructure must be similarly robust.  The catch with KSC of course is that the current pads won't take a BFR and you might need to move NASA facilities to get enough space.  Since NASA is a federal agency, they must be persuaded to move, as I've never heard of eminent domain being used by a private firm against a federal agency that relies upon said agency for much of its money.  The good news with Vieques is that it already has roads, schools, a police force, fire department, power plant, desalination plant, an airport and a port which connects to the mainland.  The main issue with Vieques is these simply need to be upgraded.  Since the mainland will have power to spare given Puerto Rico's population loss, you can arguably get around the power issue by laying a power cable from mainland Puerto Rico to Vieques (the UK is studying a more ambitious power cable from Iceland: http://www.independent.co.uk/news/uk/home-news/david-cameron-to-announce-plan-to-power-uk-by-harnessing-icelands-volcanoes-a6712961.html).  Everything else however would require upgrading what is already there or building all-new in some cases, but while it would take longer it might prove less complicated than finding space at the Cape or launching off-shore at Brownsville. 
 
Title: Re: Where will BFR launch from?
Post by: Ludus on 05/24/2016 04:08 am
Building site, new factory located at former location of the Sea Launch Home port.

An alternative to building the factory at the launch site is to build it with direct access to seagoing ships so it can ship assembled BFR stages to any launch site on the ocean which is pretty much all plausible sites.

The Sealaunch facility location in Long Beach satisfies that. It seems to have enough space (barely) for a rocket factory. It has great access to all forms of transport and all needed infrastructure.

Importantly it's so close to Hawthorne that SpaceX employees could treat it as an extension of the current facility. That makes transition to new production a lot easier to organize than any facility not nearby.

Sealaunch seems to be near liquidation.

BFR made there could be shipped to Vandenburg as Helodriver suggested or to any of the other possible launch sites. Putting it in Long Beach means it could ship to any launch site or multiple sites. As a location it would allow final decisions about launch sites to be delayed.
Title: Re: Where will BFR launch from?
Post by: Ludus on 05/24/2016 04:24 am
The Sealaunch Commander seen docked across from the Ocean Odyessy launch platform is 666' (203m) long which seems to be about the same as the width of the site. A factory could be 150m X 800m or more. It would have direct docking of seagoing ships, a rail line, direct access to container and bulk shipments. The site is secure and was already used for similar purposes so doesn't have zoning or political issues.
Title: Re: Where will BFR launch from?
Post by: sghill on 05/24/2016 11:23 am
The problem with a launch platform in the Gulf (or off the Cape) is that a big hurricane could put you out of commission for a long time.

On a related note, redundancy in the event of natural disaster is why you want more than one launch site. You don't want a bad hurricane in the Gulf to mean that Mars doesn't get resupplied this window.

That's mostly a moot point.

Your chances of a hurricane are about equal from any eastern North American costal site far enough south to matter. What changes is the month.
Title: Re: Where will BFR launch from?
Post by: bstrong on 05/24/2016 12:03 pm
The problem with a launch platform in the Gulf (or off the Cape) is that a big hurricane could put you out of commission for a long time.

On a related note, redundancy in the event of natural disaster is why you want more than one launch site. You don't want a bad hurricane in the Gulf to mean that Mars doesn't get resupplied this window.

That's mostly a moot point.

Your chances of a hurricane are about equal from any eastern North American costal site far enough south to matter. What changes is the month.
My point was more that a platform is much more vulnerable to hurricane damage than a pad on shore.
Title: Re: Where will BFR launch from?
Post by: spacenut on 05/24/2016 12:45 pm
There are hundreds of oil platforms in the Gulf, and most get up and running after the strong wind/rain goes by from a hurricane.  Most damage is from older homes/businesses which were not built to withstand hurricane winds.  Also, a really bad hurricane usually only happens in the Gulf about every 10 years or so on average.  This could happen anywhere, an island in the Pacific would also be subject to typhoons and hurricanes, also a lot of thundershowers.  If they want to launch a lot, they will need a lot of launch pads.  Power outages are the biggest problem with hurricanes.  Having back up generators would solve this problem.  The other problem is storm surge water damage.  All the new high rise condos in the Gulf have their pools and gyms on the first floors and are water proofed to absorb 14-20' storm surges.  So are drilling platforms.  Katrina was handled ok from the wind and storm surge.  They had so much rain the Mississippi swelled and caused the levees to break and flood New Orleans which was a few days afterward.  The Space Shuttle tank manufacturing facility weathered the storm ok. 

It is going to take a lot of fuel to fly MCT's to Mars.  During the off window, fuel depots can be filled, and even cargo MCT's can be launched awaiting the TMI window.  Every launch doesn't have to take place during the 6 month window. 
Title: Re: Where will BFR launch from?
Post by: sghill on 05/24/2016 12:55 pm
The problem with a launch platform in the Gulf (or off the Cape) is that a big hurricane could put you out of commission for a long time.

On a related note, redundancy in the event of natural disaster is why you want more than one launch site. You don't want a bad hurricane in the Gulf to mean that Mars doesn't get resupplied this window.

That's mostly a moot point.

Your chances of a hurricane are about equal from any eastern North American costal site far enough south to matter. What changes is the month.
My point was more that a platform is much more vulnerable to hurricane damage than a pad on shore.

There will be no on-shore launch facilities for BFR anywhere on US territory coastline.

Show me a single suitable place in the US or its territories that is neither built up already nor already protected shoreline, and I will happily- nay giddily- retract my statement.

Something as large as BFR launching repeatedly (once a month or more) is never going to be allowed near people or coastal protected areas.

I firmly stand by my 5-mile raised causeway idea not because I like it, but because I don't see an alternative that ticks off BOTH the SpaceX ease and cost of operations needs and also the concerned public needs checkboxes. :)

http://forum.nasaspaceflight.com/index.php?topic=35248.msg1236646#msg1236646

 
Title: Re: Where will BFR launch from?
Post by: bstrong on 05/24/2016 02:05 pm
There are hundreds of oil platforms in the Gulf, and most get up and running after the strong wind/rain goes by from a hurricane.  Most damage is from older homes/businesses which were not built to withstand hurricane winds.  Also, a really bad hurricane usually only happens in the Gulf about every 10 years or so on average.  This could happen anywhere, an island in the Pacific would also be subject to typhoons and hurricanes, also a lot of thundershowers.

Hmm, 113 oil platforms were totally destroyed by Katrina. Shore-based infrastructure held up a lot better, generally speaking. Unless you keep a spare in a protected harbor somewhere, you could be out of commission for a year or more while your platform is rebuilt. And the trend seems to be that climate change is making this sort of event more frequent.

In the long run, this will be addressed with redundancy, but with Elon's stated timeline, they will probably be putting people on Mars before they have multiple launch sites, so they need to make sure that the first one they build is as resilient as possible to natural disasters. Even if the colony keeps enough reserve supplies to last until the next window if the launch site is down for one, that would likely be a significant hardship and a deterrent to future colonists.

There will be no on-shore launch facilities for BFR anywhere on US territory coastline.

Show me a single suitable place in the US or its territories that is neither built up already nor already protected shoreline, and I will happily- nay giddily- retract my statement.

Something as large as BFR launching repeatedly (once a month or more) is never going to be allowed near people or coastal protected areas.

I firmly stand by my 5-mile raised causeway idea not because I like it, but because I don't see an alternative that ticks off BOTH the SpaceX ease and cost of operations needs and also the concerned public needs checkboxes. :)

http://forum.nasaspaceflight.com/index.php?topic=35248.msg1236646#msg1236646

You may be right about coastal launch sites, though I think there is a lot of merit to Helodriver's suggestion upthread of SLC-6. Not optimal inclination by a long shot, but not prohibitive either, as I understand it. And it ticks a lot of other boxes: you can put the factory in Long Beach and staff it from the HQ workforce, it would probably be easier to get the permits since it's an existing launch site, and you don't have to worry about hurricanes or typhoons. Once you have a more optimal (and likely more hurricane-prone) second launch site, SLC-6 can be used for backup and surge capacity.

The second best option, in my opinion, is an uninhabited island in the Pacific or Caribbean (I suspect Elon's "volcanic lair" tweet was an oblique reference to BFR launch site options). You may still have to deal with hurricanes/typhoons, but they will be less likely to take out the whole launch site if it is built on shore.
Title: Re: Where will BFR launch from?
Post by: oldAtlas_Eguy on 05/24/2016 02:29 pm
A BFR and BFS stack fully fueled will weigh ~4,600mt in a small footprint of 15m diameter. That is ~26mt per m^2. You will need a location that has a very solid bedrock to put the pad. Otherwise it will slowly sink or tilt. That then is a volcanic island with its harder ground makeup closer to the surface. Plus a volcanic island means that the pad can be elevated from sea level significantly so no damage from stormsurge.

No matter where you put it the prep work for the ground will be a large project and require significant amount of time. Example Boca Chica ground stabilization work measured in years. It can be done but is not trivial.
Title: Re: Where will BFR launch from?
Post by: sghill on 05/24/2016 02:55 pm
A BFR and BFS stack fully fueled will weigh ~4,600mt in a small footprint of 15m diameter. That is ~26mt per m^2. You will need a location that has a very solid bedrock to put the pad. Otherwise it will slowly sink or tilt. That then is a volcanic island with its harder ground makeup closer to the surface. Plus a volcanic island means that the pad can be elevated from sea level significantly so no damage from stormsurge.

No matter where you put it the prep work for the ground will be a large project and require significant amount of time. Example Boca Chica ground stabilization work measured in years. It can be done but is not trivial.

I totally agree.

But I think operations will be on land and the launch pads (and landing pad) will be off-shore.  Then you need a way to connect the two, and boats are too slow and expensive (and SpaceX has learned how expensive island-based launch operations are), so you need a raised causeway that sits high up enough to not worry about storms.  Any southern coastal industrial area that wants the project will do in this scenario.

The cost estimate I did in my previous link showed a 5-mile raised causeway would cost about $500 million.  That's not chump change to be sure, but the ease of on-shore operations near population centers with the flexibility of launching from away from the coast gives a ton of positives.

Putting all the operations on shore and then wheeling the BFR via rails out to an offshore launch pad that blasts down into open water gets you all the benefits of on-shore operations plus all the benefits of being safely away from people and animals with your launch and landing pads.  It gets your noise away from people and animals so you can have a higher launch rate, it gets you the ability to rapidly access the booster and launch pad (versus travel by boat) by driving out to the pad, and with an over water launch pad where the rocket is held Soyuz-style above the water, it gets you sound and shockwave absorption, so your pad isn't as complex.  The pad doesn't have to be as robust if it's out 30 feet above open water.  And if there's a disaster, well, the whole booster falls into the water.  Polluting to be sure, but so is any on-shore disaster, so the opportunity cost is equivalent (or lower) IMHO.

Drive your pylons down to bedrock and drive in as many as you need to harden the site from weather and vibration.  It's easier than bulldozing dirt, waiting for it to settle, bulldozing more dirt, waiting for it to settle, then spending months pouring concrete into a new pad that will be bigger than pads 39.

We know how to drive lots and lots of pylons into the sea floor, and compared to constructing a land-based launch pad of this size, the time to construct it may even be faster.  The Virginia Spaceport pad took years and years, and it's barely a scratch on the seashore.

And as far as referencing Katrina.  Hundreds of older and abandoned oil rigs  (and also Lake Poncitrain causeway) getting destroyed is hardly a valid comparison.  We can engineer oil rigs (and causeways) to whatever threats we want to survive.  It's all about price trade-offs if you build something to survive a Category 1-4 storm versus surviving a Category 5 storm.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/24/2016 03:09 pm
Problem with that plan is it'd take too long to transport the booster to the launch site. You want those boosters flying with a fast turnaround, so you're better off putting the landing pad very near (<1km) the launch pad so you could, in principle, snap a BFS to the top of it, fuel it up, and launch the same booster (not the same BFS) within, say, an hour of landing.

The BFSes could be transported from shore. They're smaller and wouldn't have as fast of a turnaround anyway (in fact many of them would only do one mission every 2 years, though the tankers would be much faster).
Title: Re: Where will BFR launch from?
Post by: sghill on 05/24/2016 03:13 pm
Problem with that plan is it'd take too long to transport the booster to the launch site. You want those boosters flying with a fast turnaround, so you're better off putting the landing pad very near (<1km) the launch pad so you could, in principle, snap a BFS to the top of it, fuel it up, and launch the same booster (not the same BFS) within, say, an hour of landing.

The BFSes could be transported from shore. They're smaller and wouldn't have as fast of a turnaround anyway (in fact many of them would only do one mission every 2 years, though the tankers would be much faster).

Huh? A five mile drive on rails is nothing compared ideas about putting one on a floating platform via boat delivery.  But I've got my launch and landing pads off shore, so the distance between them may not be great.

Any delivery means of a few hours isn't going to affect launch tempo business model of BFR.  And if it does affect the business model, then you can guarantee land launches (and landings) of the thing are not on the table. 

So either way you are back to my model as the path of least resistance.
Title: Re: Where will BFR launch from?
Post by: miscme on 05/24/2016 03:17 pm
The BFSes could be transported from shore. They're smaller and wouldn't have as fast of a turnaround anyway (in fact many of them would only do one mission every 2 years, though the tankers would be much faster).

The MCT would have a mission every 2 years however the BFS (Big F%@!ing Secondstage) would have one mission for every BFR launch to send fuel to orbital tankers.

I think the estimate was that they needed 3 tanker launches for every MCT launch
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/24/2016 03:19 pm
Problem with that plan is it'd take too long to transport the booster to the launch site. You want those boosters flying with a fast turnaround, so you're better off putting the landing pad very near (<1km) the launch pad so you could, in principle, snap a BFS to the top of it, fuel it up, and launch the same booster (not the same BFS) within, say, an hour of landing.

The BFSes could be transported from shore. They're smaller and wouldn't have as fast of a turnaround anyway (in fact many of them would only do one mission every 2 years, though the tankers would be much faster).

Huh? A five mile drive on rails is nothing compared ideas about putting one on a floating platform via boat delivery.
Huh? Who said boat delivery? I said landing pad. Land the rocket on the same platform/island/whatever as the launch pad.

...but I suppose a fast (10-20mph?) rail delivery of the BFR booster over 5 miles could work just fine, too. I was just picturing something slow like the crawlers used for Saturn V and Shuttle.


I simply think there should be no part of the process that should take several hours or days and become a bottleneck. Obviously you're not going to be launching every hour (or even every day) at first, but the process needs to be capable of getting that high of a turnaround in principle so that you can get within an order of magnitude of that in practice.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/24/2016 03:21 pm
The BFSes could be transported from shore. They're smaller and wouldn't have as fast of a turnaround anyway (in fact many of them would only do one mission every 2 years, though the tankers would be much faster).

The MCT would have a mission every 2 years however the BFS (Big F%@!ing Secondstage) would have one mission for every BFR launch to send fuel to orbital tankers.

I think the estimate was that they needed 3 tanker launches for every MCT launch
BFS is the MCT (or what we've been calling the MCT). BFS stands for "Big F*ing Spaceship."
Title: Re: Where will BFR launch from?
Post by: bstrong on 05/24/2016 03:37 pm
@sghill: I don't know much about offshore platforms, so if you have expertise in the area and think it's reasonable to build one that has a very high probability of surviving a 100-year storm, I'll take your word for it.

Just reading up on it a bit, I came across this article: http://www.nola.com/katrina/index.ssf/2015/08/energy_industry_adapts_but_sto.html

It suggests that the platforms that can handle the heaviest storms are the moored type that are used in the North Sea, which I believe often run into the multiple billions to construct and are designed for deep water. Also, the deck height may need to be closer to 100ft than 30ft. It's probably a solvable problem to build something that meets requirements, but it may be quite expensive. And what's currently being built in the Gulf, even post-Katrina, may not be sufficient.
Title: Re: Where will BFR launch from?
Post by: envy887 on 05/24/2016 03:45 pm
The BFSes could be transported from shore. They're smaller and wouldn't have as fast of a turnaround anyway (in fact many of them would only do one mission every 2 years, though the tankers would be much faster).

The MCT would have a mission every 2 years however the BFS (Big F%@!ing Secondstage) would have one mission for every BFR launch to send fuel to orbital tankers.

I think the estimate was that they needed 3 tanker launches for every MCT launch
BFS is the MCT (or what we've been calling the MCT). BFS stands for "Big F*ing Spaceship."
More likely MCT as a system will have a mission every 4 years. There are too many synods that have no feasible trajectories to return in time for a 2-year cadence.
Title: Re: Where will BFR launch from?
Post by: llanitedave on 05/24/2016 03:49 pm
Texas is still not out of the question for a BFR launch site.  There is some near-uninhabited land just north of Brownsville, inland from Padre Island and Laguna Madre, between Port Mansfield and Arroyo City.  Most of the infrastructure in that area is oil/gas and ranching, not residential.  Overflights would be of the uninhabited part of Padre Island National seashore.  That's probably the emptiest remaining landscape in the U.S. that's appropriate for launching, while still being in close proximity to transportation and manufacturing facilities.
Title: Re: Where will BFR launch from?
Post by: bstrong on 05/24/2016 03:55 pm
Fair enough, my point remains valid that it's a trade off of money versus survivability and other benefits gained per dollar spent.

A billion here and there is barely a rounding error compared to what NASA has spent on Constellation and SLS.

Thinking about it some more, building them relatively cheaply and keeping spares somewhere might not actually be a terrible idea and would likely be cheaper. Or just tow them into harbor when a big storm is coming. And if the causeway is destroyed, you can always fall back to boats/barges.

I'm coming around to your idea. I just think resiliency needs to be one of the primary site selection/design criteria, at least for the first site. Missing out on resupplying the colony will be a very, very bad thing.
Title: Re: Where will BFR launch from?
Post by: llanitedave on 05/24/2016 04:03 pm
Texas is still not out of the question for a BFR launch site.  There is some near-uninhabited land just north of Brownsville, inland from Padre Island and Laguna Madre, between Port Mansfield and Arroyo City.  Most of the infrastructure in that area is oil/gas and ranching, not residential.  Overflights would be of the uninhabited part of Padre Island National seashore.  That's probably the emptiest remaining landscape in the U.S. that's appropriate for launching, while still being in close proximity to transportation and manufacturing facilities.

Hourly, daily, weekly, and even monthly launches and landings of the BFR will not be occurring on Padre Island National Seashore.  It goes against the very concept of a protected area.

I applaud you suggesting a specific site though. May I suggest that anyone who wants to discuss onshore launch operations for this launch system do the same. :)


It wouldn't be 'on" the seashore, it would be overflying the seashore at a high altitude.  It would launch from the mainland, west of Laguna Madre.  There's plenty of empty land there with margins to the east and southeast.  It's far enough away from anything to minimize acoustic disturbances (although still probably audible for a hundred miles)


Edit:  A bit north of Port Mansfield might be even better, from the standpoint of not interfering with existing population.  That's the old King Ranch area, there's nobody around there for miles.
Title: Re: Where will BFR launch from?
Post by: RedLineTrain on 05/24/2016 04:21 pm
For reference, here is a map of the Brownsville sea depth (in fathoms).  5 miles from the Boca Chica launch site to the BFR platform would be roughly 11 to 13 fathoms (66 to 78 feet or 20 to 23 meters) deep.

http://www.charts.noaa.gov/OnLineViewer/11300.shtml

Here is a map of the Cape Canaveral sea depth (in feet).  5 miles from 39A to the BFR platform would be roughly roughly 40 feet (7 fathoms or 12 meters) deep.

http://www.charts.noaa.gov/OnLineViewer/11484.shtml

6 feet per fathom.  1.8 meters per fathom.  3.28 feet per meter.

Corrections welcome.
Title: Re: Where will BFR launch from?
Post by: bstrong on 05/24/2016 04:37 pm
I'm waiting for the EIS that takes into consideration the public benefit of allowing access to the scenic beauty of Mars. Seems like a good trade-off for closing one beach on Earth.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/24/2016 05:12 pm
The BFSes could be transported from shore. They're smaller and wouldn't have as fast of a turnaround anyway (in fact many of them would only do one mission every 2 years, though the tankers would be much faster).

The MCT would have a mission every 2 years however the BFS (Big F%@!ing Secondstage) would have one mission for every BFR launch to send fuel to orbital tankers.

I think the estimate was that they needed 3 tanker launches for every MCT launch
BFS is the MCT (or what we've been calling the MCT). BFS stands for "Big F*ing Spaceship."
More likely MCT as a system will have a mission every 4 years. There are too many synods that have no feasible trajectories to return in time for a 2-year cadence.
That's not true. You just need to refuel in orbit (and perhaps a higher orbit), then you have plenty of delta-v for the trajectory even for a difficult year.
Title: Re: Where will BFR launch from?
Post by: Ionmars on 05/24/2016 05:18 pm
For reference, here is a map of the Brownsville sea depth (in fathoms).  5 miles from the Boca Chica launch site to the BFR platform would be roughly 11 to 13 fathoms (66 to 78 feet or 20 to 23 meters) deep.

http://www.charts.noaa.gov/OnLineViewer/11300.shtml

Here is a map of the Cape Canaveral sea depth (in feet).  5 miles from 39A to the BFR platform would be roughly roughly 40 feet (7 fathoms or 12 meters) deep.

http://www.charts.noaa.gov/OnLineViewer/11484.shtml

6 feet per fathom.  1.8 meters per fathom.  3.28 feet per meter.

Corrections welcome.
Thank you. Very good to know these facts, which point to Florida offshore as the less expensive location to build sghill's causeway. May not be the only consideration, though.  If we have a tsumami, the ocean-generated super-wave will rise up higher over shallow water than over deeper water.

http://www.abc.net.au/science/surfingscientist/ask/tidalwaves.htm
 
On the other hand, the Atlantic Ocean is less likely to generate a tsunami from an under-ocean earthquake than the Pacific Ocean, so both Texas and Florida may be spared.
Title: Re: Where will BFR launch from?
Post by: Ludus on 05/24/2016 05:45 pm
I think a factory at SeaLaunch in Long Beach works well with off shore launch. There's a work flow that never leaves the ocean.

Long Beach would ship to any launch site. The launch sites would use a platform built like a oil platform say 10 miles offshore. A horizontal integration facility would be build on the shore like a boat house with water under the structure. The strong back would sit on BF Barge that locks into the boathouse HIF. The strongback and HIF would just be BF upscale versions of the Falcon process. Assembled stages would arrive from Longbeach and be directly unloaded. The BFR/BFS would be assembled on the strongback in the HIF. When ready it would float out and be moved 10 miles offshore to the launch platform.

The barge and strongback supporting the BFR/BFS would just be the equivalent of the set of rail tracks and strong back used for Falcon or the crawler and vertical integration facility used for shuttle and Apollo.

The BF barge and strongback would go under the launch platform. Just the Strongback and rocket would be pulled up to the launch platform level, the barge would be decoupled and stay behind. Once in place the strong back would erect the BFR/BFS in place for loading propellant.

The BFR booster would return to a BF ASDS either near the launch site or out to sea. Either way it would take the returned booster directly back to the HIF. The entire work flow would be on the ocean, though all infrastructure and most workers would remain ashore.
Title: Re: Where will BFR launch from?
Post by: envy887 on 05/24/2016 05:46 pm
More likely MCT as a system will have a mission every 4 years. There are too many synods that have no feasible trajectories to return in time for a 2-year cadence.
That's not true. You just need to refuel in orbit (and perhaps a higher orbit), then you have plenty of delta-v for the trajectory even for a difficult year.
I'm not as worried about dv as I am about reentry velocity at Earth. Most returns on 2-year or faster round trips have highly elliptic orbits with perihelions much less than 1 AU, and as a result have reentries at 15 - 20 km per second. At that speed direct entry or orbital insertion are both quite difficult.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/24/2016 05:58 pm
More likely MCT as a system will have a mission every 4 years. There are too many synods that have no feasible trajectories to return in time for a 2-year cadence.
That's not true. You just need to refuel in orbit (and perhaps a higher orbit), then you have plenty of delta-v for the trajectory even for a difficult year.
I'm not as worried about dv as I am about reentry velocity at Earth. Most returns on 2-year or faster round trips have highly elliptic orbits with perihelions much less than 1 AU, and as a result have reentries at 15 - 20 km per second. At that speed direct entry or orbital insertion are both quite difficult.
Not likely direct entry but multiple passes, perhaps with propulsive assist on the first pass. Again, refueling in orbit addresses that.
Title: Re: Where will BFR launch from?
Post by: llanitedave on 05/24/2016 06:26 pm
Texas is still not out of the question for a BFR launch site.  There is some near-uninhabited land just north of Brownsville, inland from Padre Island and Laguna Madre, between Port Mansfield and Arroyo City.  Most of the infrastructure in that area is oil/gas and ranching, not residential.  Overflights would be of the uninhabited part of Padre Island National seashore.  That's probably the emptiest remaining landscape in the U.S. that's appropriate for launching, while still being in close proximity to transportation and manufacturing facilities.

Hourly, daily, weekly, and even monthly launches and landings of the BFR will not be occurring on Padre Island National Seashore.  It goes against the very concept of a protected area.

I applaud you suggesting a specific site though. May I suggest that anyone who wants to discuss onshore launch operations for this launch system do the same. :)


It wouldn't be 'on" the seashore, it would be overflying the seashore at a high altitude.  It would launch from the mainland, west of Laguna Madre.  There's plenty of empty land there with margins to the east and southeast.  It's far enough away from anything to minimize acoustic disturbances (although still probably audible for a hundred miles)

They'd have to close the seashore for overflights.  Closures are already a well publicized problem at the Brownsville site, and they are years away from once a month launches.  Again, this is a non-starter because of the needs of non-participants.

I know I'm droning on about this ad nauseum (and I don't like hogging thread conversations), but if this thread is to have any value,  we can't have fantasy sites where non participants don't exist. So let's identify specific scenarios and why they will work or won't work (which I realize you are doing.)


I can't see the current system of setting up large exclusion zones for launches holding out forever.  If that remains the case, then there will soon be no place on the planet that can be realistically launched from.  After all, airliners fly over your head multiple times a day, and so do light planes which don't have the same safety record as the larger commercial planes. I do think that SpaceX needs to prove out their reliability, and ramp up the launch rate gradually.  It will take time before any governing body decides that launches are safe enough to reduce restriction zones, but it pretty much has to happen if Mars launches become a regular reality.


The advantage to Padre Island is that it's a true roadless area.  The road from the South Padre Island resorts ends well south of Port Mansfield.  Visitation is very low, and any debris risk would be correspondingly miniscule.  The same is true for the mainland west of Laguna Madre.  It's probably one of the safest areas in the world for launching rockets.
Title: Re: Where will BFR launch from?
Post by: envy887 on 05/24/2016 07:03 pm
More likely MCT as a system will have a mission every 4 years. There are too many synods that have no feasible trajectories to return in time for a 2-year cadence.
That's not true. You just need to refuel in orbit (and perhaps a higher orbit), then you have plenty of delta-v for the trajectory even for a difficult year.
I'm not as worried about dv as I am about reentry velocity at Earth. Most returns on 2-year or faster round trips have highly elliptic orbits with perihelions much less than 1 AU, and as a result have reentries at 15 - 20 km per second. At that speed direct entry or orbital insertion are both quite difficult.
Not likely direct entry but multiple passes, perhaps with propulsive assist on the first pass. Again, refueling in orbit addresses that.

Multiple passes doesn't help much, considering that they have to get below escape velocity on the first pass and any interplantary or lunar trajectory is already reentering at near escape velocity. On those returns they will frequently need to shed 6-9 KM/s on the first pass just to stay in a high energy Earth orbit. It also doesn't help that TEI dv's to get the elliptical return trajectory are also pretty high, up to 4 or 5 km/s. So you need as much as 10-14 km/s between LMO and HEO and there's nowhere to refuel in between.

If you refuel in LMO, have 6-7 km/s available from there to do 4 km/s TEI and 2-3 km/s braking burn and can then survive a 12-13 km/s reentry, it's might be feasible. Very high PMF, and LMO refueling, are both critical though. It might be cheaper to build a less mass efficient vehicle, save the expense of LMO refueling, and just make twice as many.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/24/2016 08:13 pm
More likely MCT as a system will have a mission every 4 years. There are too many synods that have no feasible trajectories to return in time for a 2-year cadence.
That's not true. You just need to refuel in orbit (and perhaps a higher orbit), then you have plenty of delta-v for the trajectory even for a difficult year.
I'm not as worried about dv as I am about reentry velocity at Earth. Most returns on 2-year or faster round trips have highly elliptic orbits with perihelions much less than 1 AU, and as a result have reentries at 15 - 20 km per second. At that speed direct entry or orbital insertion are both quite difficult.
Not likely direct entry but multiple passes, perhaps with propulsive assist on the first pass. Again, refueling in orbit addresses that.

Multiple passes doesn't help much, considering that they have to get below escape velocity on the first pass and any interplantary or lunar trajectory is already reentering at near escape velocity. On those returns they will frequently need to shed 6-9 KM/s on the first pass just to stay in a high energy Earth orbit....
Correct, but this is the same order as you need for return from orbit, anyway.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/24/2016 08:18 pm
I'm certain that building a mass-efficient vehicle will be CRITICAL to making this whole enterprise work. SpaceX was able to do first-ever orbital booster VTVL recovery only because they had one of the most mass-efficient rockets EVER in the history of ever. The Merlin 1D, for instance, has vacuum T/W of 180 and its uprated version (hasn't flown at this thrust) has a T/W of 200, 2.5x that of RD-180.

You can't make it work economically without a very mass-efficient vehicle because you'll be forced to use it only once every 4 years (like you suggest) or require more staging.

Yeah, I think 6-7km/s is around the right performance level. Of course, we don't know the exact figures.
Title: Re: Where will BFR launch from?
Post by: Hyperion5 on 05/25/2016 01:52 am
If it's someplace like Vieques the timeline and price list is somewhat longer than building it at or off the cape or even Brownsville where most support infrastructure is already in place. Vieques appears to need a port and runway built before major construction on a factory and launchpad could start. It would need a new power plant, probably a desalination plant, roads, a pretty long expensive list of stuff.

I like PR as a launch site, but it will NOT be in Vieques.  The locals have decades of violent protest history against big military and industrial projects.  The anti-development crowd would make enough noise to kill this before it ever got out of the planning commission. And SpaceX has a history of following incentives dollars-which PR definitely does not have right now.

https://www.youtube.com/watch?v=RNGH-3KnQfw

Silly as it sounds, I'm sticking with my raised causeway offshore near Galveston or Houston as the site. TX DOT has the money to build one, TX has the infrastructure to support it,  and TX government has the incentives and motivation to lure it.

Spacex's launch sites are not associated with 2000 tonnes of annual bomb-dropping, a 55% above average infant mortality rate or the depositing of large amounts of napalm, cadmium, arsenic and mercury into an environment.  Also the type of jobs Spacex would bring to Puerto Rico would be far more lucrative than anything the Navy offered.  You may doubt the idea, but until someone tries it, the idea that the proposal is dead on arrival is just a hypothesis.  One thing Vieques does have going for it is that it is a sizable, lightly populated island near a major population center, which makes it an arguably more feasible launch site than a small, unpopulated Pacific island miles from anything.  It also has room for 2 launchpads, a landing pad, a test stand and a factory a safe distance from people on strong, volcanic soil with no causeways needed.  That's a half billion in savings that can be used to address infrastructure needs.
Title: Re: Where will BFR launch from?
Post by: Hyperion5 on 05/25/2016 02:32 am
Problem with that plan is it'd take too long to transport the booster to the launch site. You want those boosters flying with a fast turnaround, so you're better off putting the landing pad very near (<1km) the launch pad so you could, in principle, snap a BFS to the top of it, fuel it up, and launch the same booster (not the same BFS) within, say, an hour of landing.

The BFSes could be transported from shore. They're smaller and wouldn't have as fast of a turnaround anyway (in fact many of them would only do one mission every 2 years, though the tankers would be much faster).

Huh? A five mile drive on rails is nothing compared ideas about putting one on a floating platform via boat delivery.
Huh? Who said boat delivery? I said landing pad. Land the rocket on the same platform/island/whatever as the launch pad.
...

It's inherent in the math, Robotbeat.  You can get to Mars with a fully-crewed MCT in 4 launches ONLY if you land the core stage on a barge down-range and use tankers with super-sized tanks for refueling.  Using a gigantic ASDS down-range keeps payload loss to a minimum (less than 5%), so boat delivery is a must for getting a full payload into orbit.  As soon as you start doing RTLS the launches required jumps by more than double due to the huge loss in payload capacity.  That's more than double the flight risk, propellant expense, environmental impact, and wear and tear on the launchpad(s) and landing pad(s).  While I know engineers can do a lot, it's still difficult to minimize the impact of an LV with 2X the thrust of a Saturn V.  Unless Spacex goes with an all-RTLS approach, which is not compatible with a full cargo load, then selecting a site with the ability to handle boat delivery is a must. 
Title: Re: Where will BFR launch from?
Post by: DigitalMan on 05/25/2016 04:01 am
...
...
...
It's inherent in the math, Robotbeat.  You can get to Mars with a fully-crewed MCT in 4 launches ONLY if you land the core stage on a barge down-range and use tankers with super-sized tanks for refueling.  Using a gigantic ASDS down-range keeps payload loss to a minimum (less than 5%), so boat delivery is a must for getting a full payload into orbit.  As soon as you start doing RTLS the launches required jumps by more than double due to the huge loss in payload capacity.  That's more than double the flight risk, propellant expense, environmental impact, and wear and tear on the launchpad(s) and landing pad(s).  While I know engineers can do a lot, it's still difficult to minimize the impact of an LV with 2X the thrust of a Saturn V.  Unless Spacex goes with an all-RTLS approach, which is not compatible with a full cargo load, then selecting a site with the ability to handle boat delivery is a must.

Personally I hope they launch from KSC

1. I live here and I LIKE rockets.  Everyone else can move if need be.
2. CCAFS and KSC have been here a long time and the future commercial-driven growth will be exciting
3. Since KSC was the departure point for the moon landings I really think KSC deserves to be the departure point for Mars landings.
Title: Re: Where will BFR launch from?
Post by: Impaler on 05/25/2016 09:41 am
Problem with that plan is it'd take too long to transport the booster to the launch site. You want those boosters flying with a fast turnaround, so you're better off putting the landing pad very near (<1km) the launch pad so you could, in principle, snap a BFS to the top of it, fuel it up, and launch the same booster (not the same BFS) within, say, an hour of landing.

The BFSes could be transported from shore. They're smaller and wouldn't have as fast of a turnaround anyway (in fact many of them would only do one mission every 2 years, though the tankers would be much faster).

Huh? A five mile drive on rails is nothing compared ideas about putting one on a floating platform via boat delivery.
Huh? Who said boat delivery? I said landing pad. Land the rocket on the same platform/island/whatever as the launch pad.

...but I suppose a fast (10-20mph?) rail delivery of the BFR booster over 5 miles could work just fine, too. I was just picturing something slow like the crawlers used for Saturn V and Shuttle.


I simply think there should be no part of the process that should take several hours or days and become a bottleneck. Obviously you're not going to be launching every hour (or even every day) at first, but the process needs to be capable of getting that high of a turnaround in principle so that you can get within an order of magnitude of that in practice.


The Shuttle Crawler moves at 1 mph when carrying the shuttle and only takes 5 hours to go from the VAB to the pad, it is not remotely a bottleneck that needs to be replaced, and even then it could easily have it's speed doubled to 2 mph for less then constructing a new rail system (Crawler already goes 2 mph when unladen now so it is capable of this speed if it simply gets more juice to traction motors perhaps by an electric pickup of around 6-8 MW).  Imagine if Musk puts some Tesla logos on the thing after the upgrade.  BTW the crawlers don't stay at the pad during launch they can head right back to the VAB as soon as the BFR has been delivered to the pad.

Second the ground structure probably dose not allow a rail system which was considered and rejected when the whole complex was built, this is the Florida coast which is basically sand and the Crawler moves down a highway of crushed rock, but the rocks are just 2 m deep, the depth of a normal roadbed which is probably as deep as you can go before you hit the water table at the Cape.  I suspect rail was rejected because the incredible pressure on a rail would necessitate huge concrete footings that would sink perpetually (where as the gravel road just gets more gravel dumped on it as it compresses). Also the actual launch pads are significantly elevated above the surrounding terrain and rail vehicles can't go up grades of more then a 2-3% but the crawler easily tackles a much steeper grade.

Remember that while the Soviets used rails to very rapidly move the Soyuz to the launch pad they are building on firmer soil and working with a vehicle that is already transported from the manufacturing site cross-country by rail.  Also they do it all horizontally which distributes the weight much better and the Soyuz launch pad basically juts out over a bowl in the ground that acts as the flame trench so the rail line is completely flat.  At the cape the topography works against rail transport.

Finally the Crawler would be of huge assistance to re-assembling returned first stage as the crawler can go out onto the landing pad driving right up to the landed stages and use a crane to pick up the stage and place it on it's back and take it back into an assembly building.  Rail roads can't do that because the vehicle could be anywhere within a large landing pad.
Title: Re: Where will BFR launch from?
Post by: Impaler on 05/25/2016 09:51 am

Multiple passes doesn't help much, considering that they have to get below escape velocity on the first pass and any interplantary or lunar trajectory is already reentering at near escape velocity. On those returns they will frequently need to shed 6-9 KM/s on the first pass just to stay in a high energy Earth orbit. It also doesn't help that TEI dv's to get the elliptical return trajectory are also pretty high, up to 4 or 5 km/s. So you need as much as 10-14 km/s between LMO and HEO and there's nowhere to refuel in between.

If you refuel in LMO, have 6-7 km/s available from there to do 4 km/s TEI and 2-3 km/s braking burn and can then survive a 12-13 km/s reentry, it's might be feasible. Very high PMF, and LMO refueling, are both critical though. It might be cheaper to build a less mass efficient vehicle, save the expense of LMO refueling, and just make twice as many.

Not much point arguing with Rb that the performance needed for his mission is unreasonable, he will always just raise his vehicles propellant fraction to what ever amount is needed to make his DeltaV target close.  But if you want to continue this I'd recommend we move to MCT spec-4 thread, personally I agree that single synod round trips are not worth it, they are the SSTO equivalent, at the very edge of our technological grasp but far beyond the cost optimum point which is to go very slow and do a 2 synod round trip. 
Title: Re: Where will BFR launch from?
Post by: envy887 on 05/25/2016 01:19 pm
Agreed, all the 2 v 4 year round trip discussion belongs in MCT speculation. BFR flight rate isn't dependent on that, and will be (eventually) very high either way.
Title: Re: Where will BFR launch from?
Post by: spacenut on 05/25/2016 01:55 pm
The crawler at Kennedy also has a much bigger footprint to spread the weight over a larger area than wheels from a rail system.  A rail system could have been build, but like it was said a huge concrete pad would have to be built to spread the weight from the rails. 

A large Sealaunch type ship could be built to launch the BFR, but another ship would have to accompany it to land on, then both would have to come back for refurbishment and loaded for another launch.  It would also probably have two more ships for lox and liquid methane.  Then loading it at sea, would require very calm waters. 

I still say at least two locations, one at the cape and one at Boca Chica, on offshore platforms, with the pipelines to carry compressed gas and compressed oxygen to the platform, then liquefied at the platform.  Either a bridge to the platform or boat or helicopter for workers and astronauts.   Other similar locations in Texas, Georgia, or Florida may be possible.  These platforms could be built to withstand CAT 5 hurricanes and waves.  You are going to have to launch east anyway to go to Mars.  There may be a possibility of a desert location, like in Eastern Nevada, but landing and having a population free area down range is a problem. 
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 05/25/2016 02:09 pm

Multiple passes doesn't help much, considering that they have to get below escape velocity on the first pass and any interplantary or lunar trajectory is already reentering at near escape velocity. On those returns they will frequently need to shed 6-9 KM/s on the first pass just to stay in a high energy Earth orbit. It also doesn't help that TEI dv's to get the elliptical return trajectory are also pretty high, up to 4 or 5 km/s. So you need as much as 10-14 km/s between LMO and HEO and there's nowhere to refuel in between.

If you refuel in LMO, have 6-7 km/s available from there to do 4 km/s TEI and 2-3 km/s braking burn and can then survive a 12-13 km/s reentry, it's might be feasible. Very high PMF, and LMO refueling, are both critical though. It might be cheaper to build a less mass efficient vehicle, save the expense of LMO refueling, and just make twice as many.

Not much point arguing with Rb that the performance needed for his mission is unreasonable, he will always just raise his vehicles propellant fraction to what ever amount is needed to make his DeltaV target close.  But if you want to continue this I'd recommend we move to MCT spec-4 thread, personally I agree that single synod round trips are not worth it, they are the SSTO equivalent, at the very edge of our technological grasp but far beyond the cost optimum point which is to go very slow and do a 2 synod round trip.
Dont argue with me, argue with SpaceX. That is how they're designing MCT.

And yeah, it IS beyond our current tech. So was Merlin 1D, achieving a ludicrously high thrust to weight ratio of 200 (for the increased thrust version), a full 2.5x that of RD-180.

MCT and BFR most definitely will be beyond current state of the art.

(Cargo may be sent---possibly without an accompanying BFS---on slower trajectories.)
Title: Re: Where will BFR launch from?
Post by: Ludus on 05/25/2016 04:22 pm
The crawler at Kennedy also has a much bigger footprint to spread the weight over a larger area than wheels from a rail system.  A rail system could have been build, but like it was said a huge concrete pad would have to be built to spread the weight from the rails. 

A large Sealaunch type ship could be built to launch the BFR, but another ship would have to accompany it to land on, then both would have to come back for refurbishment and loaded for another launch.  It would also probably have two more ships for lox and liquid methane.  Then loading it at sea, would require very calm waters. 

I still say at least two locations, one at the cape and one at Boca Chica, on offshore platforms, with the pipelines to carry compressed gas and compressed oxygen to the platform, then liquefied at the platform.  Either a bridge to the platform or boat or helicopter for workers and astronauts.   Other similar locations in Texas, Georgia, or Florida may be possible.  These platforms could be built to withstand CAT 5 hurricanes and waves.  You are going to have to launch east anyway to go to Mars.  There may be a possibility of a desert location, like in Eastern Nevada, but landing and having a population free area down range is a problem.

There is another alternative to a bridge vs boat: Hyperloop tube. If Hyperloop is a going concern manufacturing a standard tube in time, the connection from shore to a platform say 10 miles out might be cheaper and better using it. The tube would be buoyant and along with the gas pipelines, power and fiber cables would be suspended below the surface anchored to the bottom. Below the surface it isn't exposed to storms or wave action. With just anchor cables it's cheaper and quicker to build than a structure on pylons. It would be something like an inverted suspension bridge underwater, but the buoyant forces would be much weaker than gravity on a suspension bridge so it's much lighter and cheaper.

Assuming it's the Hyperloop One version, it would be sized to carry shipping containers. https://hyperloop-one.com (https://hyperloop-one.com) Covering only 10 miles it wouldn't need low pressure or very high speeds. At an average speed of 120mph it would cover 10 miles in 5 minutes. There would be no need for two tubes for travel in both directions because it's not a high volume link. The system could just alternate directions. Pods might have to wait 5 minutes for the system to switch. The run would be completely straight so it could go with lower air pressure and higher speeds without concern for lateral accelerations making passengers sick. In that case the trip could take less than 2 minutes.

There's also an obvious cool factor to taking a Hyperloop pod out to board an MCT.
Title: Re: Where will BFR launch from?
Post by: sghill on 05/25/2016 04:27 pm
The crawler at Kennedy also has a much bigger footprint to spread the weight over a larger area than wheels from a rail system.  A rail system could have been build, but like it was said a huge concrete pad would have to be built to spread the weight from the rails. 

A large Sealaunch type ship could be built to launch the BFR, but another ship would have to accompany it to land on, then both would have to come back for refurbishment and loaded for another launch.  It would also probably have two more ships for lox and liquid methane.  Then loading it at sea, would require very calm waters. 

I still say at least two locations, one at the cape and one at Boca Chica, on offshore platforms, with the pipelines to carry compressed gas and compressed oxygen to the platform, then liquefied at the platform.  Either a bridge to the platform or boat or helicopter for workers and astronauts.   Other similar locations in Texas, Georgia, or Florida may be possible.  These platforms could be built to withstand CAT 5 hurricanes and waves.  You are going to have to launch east anyway to go to Mars.  There may be a possibility of a desert location, like in Eastern Nevada, but landing and having a population free area down range is a problem.

There is another alternative to a bridge vs boat: Hyperloop tube. If Hyperloop is a going concern manufacturing a standard tube in time, the connection from shore to a platform say 10 miles out might be cheaper and better using it. The tube would be buoyant and along with the gas pipelines, power and fiber cables would be suspended below the surface anchored to the bottom. Below the surface it isn't exposed to storms or wave action. With just anchor cables it's cheaper and quicker to build than a structure on pylons. It would be something like an inverted suspension bridge underwater, but the buoyant forces would be much weaker than gravity on a suspension bridge so it's much lighter and cheaper.

Assuming it's the Hyperloop One version, it would be sized to carry shipping containers. https://hyperloop-one.com (https://hyperloop-one.com) Covering only 10 miles it wouldn't need low pressure or very high speeds. At an average speed of 120mph it would cover 10 miles in 5 minutes. There would be no need for two tubes for travel in both directions because it's not a high volume link. The system could just alternate directions. Pods might have to wait 5 minutes for the system to switch.

There's also an obvious cool factor to taking a Hyperloop pod out to board an MCT.

Talk about using a stick of dynamite when a letter opener will suffice...
Title: Re: Where will BFR launch from?
Post by: Ludus on 05/25/2016 04:34 pm
 :D Well, oddly it might actually be cheaper and quicker to build. Dynamite is also more fun.
Title: Re: Where will BFR launch from?
Post by: Impaler on 05/26/2016 07:00 am
Dont argue with me, argue with SpaceX. That is how they're designing MCT.

And yeah, it IS beyond our current tech. So was Merlin 1D, achieving a ludicrously high thrust to weight ratio of 200 (for the increased thrust version), a full 2.5x that of RD-180.

MCT and BFR most definitely will be beyond current state of the art.

(Cargo may be sent---possibly without an accompanying BFS---on slower trajectories.)

If you are claiming some source of non-public information then spill the beans OR if you're not allowed then stop trying to speak as an authority figure, no one should simply accept such a claim on your personal credibility.

And IF that is what SpaceX were planning I would tell Musk to his face it's a terrible plan if for no other reason then he can never amortize the cost of such a vehicle given the length of the synod.
Title: Re: Where will BFR launch from?
Post by: guckyfan on 05/26/2016 07:16 am

If you are claiming some source of non-public information then spill the beans

Elon Musk was very vocal about getting MCT back in the same synod for economy of reuse. Nothing secret about that.
Title: Re: Where will BFR launch from?
Post by: pobermanns on 05/26/2016 05:01 pm
For reference, here is a map of the Brownsville sea depth (in fathoms).  5 miles from the Boca Chica launch site to the BFR platform would be roughly 11 to 13 fathoms (66 to 78 feet or 20 to 23 meters) deep.

http://www.charts.noaa.gov/OnLineViewer/11300.shtml

Here is a map of the Cape Canaveral sea depth (in feet).  5 miles from 39A to the BFR platform would be roughly roughly 40 feet (7 fathoms or 12 meters) deep.

http://www.charts.noaa.gov/OnLineViewer/11484.shtml

6 feet per fathom.  1.8 meters per fathom.  3.28 feet per meter.

Corrections welcome.
Thank you. Very good to know these facts, which point to Florida offshore as the less expensive location to build sghill's causeway. May not be the only consideration, though.  If we have a tsumami, the ocean-generated super-wave will rise up higher over shallow water than over deeper water.

http://www.abc.net.au/science/surfingscientist/ask/tidalwaves.htm
 
On the other hand, the Atlantic Ocean is less likely to generate a tsunami from an under-ocean earthquake than the Pacific Ocean, so both Texas and Florida may be spared.

For what it's worth, here's a smaller-scale view of Boca Chica, with the mileage scale pasted on to it. Depths here are in feet.
Title: Re: Where will BFR launch from?
Post by: sghill on 05/26/2016 05:26 pm

For what it's worth, here's a smaller-scale view of Boca Chica, with the mileage scale pasted on to it. Depths here are in feet.

It's what's on shore that interests me.  In this case, there's nothing.

Let me give an allegory.  They don't build the Ariane 5 or Soyuz at the Guiana Space Centre- and they've got loads of land there.  The industrial base to support the activity isn't there, so they ship the rockets in- but we know that's not as economical for BFR due to its size.

You've got to look at the problem from the perspective of SpaceX and also the non-participants.  Non-participants don't need daily or weekly noise levels exceeding 200 decibels in their bedrooms or nests, and SpaceX needs economical facilities and manpower support to make the project profitable (whatever that means in this context)..

Once you make the decision to go a few miles off shore for launches to alleviate the concerns of non-participants, and on-shore for ease of construction and processing to alleviate SpaceX's financial concerns, you want to be as close to population centers and shoreline industrial centers as possible while still being able to access the rocket launch and landing facilities at any moment.  Hence, my bridge or causeway idea because you can drive across the bridge whenever you want to get out there.

I'd rather see a map of Galveston or Corpus Christie- or even Biloxi.  Lots of aerospace and industrial workers there and the facilities and manpower to support this kind of endeavour.  Same goes for Melbourne, FL. or Jacksonville.  But with all five places, once you actually look on a map, it's all either protected shoreline, residential nearby, or both.

A big honkin bridge out from KSC is "in theory" an option, but that's about it when you actually look at a map.

So creating an artificial island in super shallow water a few miles off the coast for launches and landings does seem more likely to be sure. Which kind of tilts things in Biloxi/ Mobile's and Galveston's favor or when you look at a map.

Heck, the Heald Bank is 35 miles off shore (and miles off of the main shipping lanes) in only 5 fathoms of water!!!
Title: Re: Where will BFR launch from?
Post by: bstrong on 05/31/2016 07:36 pm
I'd rather see a map of Galveston or Corpus Christie- or even Biloxi. <snip>

Good luck keeping the local fishermen out of the exclusion zone in any of those places. Seriously not a tractable problem, even if the local governments would let you attempt it. A lot fewer small craft in the Boca Chica area, as I understand it, so I think that's a much better location for your offshore launch site.
Title: Re: Where will BFR launch from?
Post by: ThereIWas3 on 05/31/2016 07:45 pm
Kansai International Airport (https://en.wikipedia.org/wiki/Kansai_International_Airport) near Osaka, Japan, was built on an artificial island 4x2.5 km, about 3km off shore, in a water depth of 60 ft.  It was designed to handle earthquakes and tidal surges of 10 ft.   I watched a documentary on it, and I think they basically paid off the fishing interests.

The major problem they have had is that the tremendous weight is compressing the seabed faster than expected and the whole thing is sinking.
Title: Re: Where will BFR launch from?
Post by: RonM on 05/31/2016 07:53 pm
Kansai International Airport (https://en.wikipedia.org/wiki/Kansai_International_Airport) near Osaka, Japan, was built on an artificial island 4x2.5 km, about 3km off shore, in a water depth of 60 ft.  It was designed to handle earthquakes and tidal surges of 10 ft.   I watched a documentary on it, and I think they basically paid off the fishing interests.

The major problem they have had is that the tremendous weight is compressing the seabed faster than expected and the whole thing is sinking.

Airports require a lot of real estate, making artificial islands practical (assuming they don't sink under their own weight). A BFR will only require a launch pad, making platforms far cheaper than an island.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 05/31/2016 09:55 pm
Kansai International Airport (https://en.wikipedia.org/wiki/Kansai_International_Airport) near Osaka, Japan, was built on an artificial island 4x2.5 km, about 3km off shore, in a water depth of 60 ft.  It was designed to handle earthquakes and tidal surges of 10 ft.   I watched a documentary on it, and I think they basically paid off the fishing interests.

The major problem they have had is that the tremendous weight is compressing the seabed faster than expected and the whole thing is sinking.

Airports require a lot of real estate, making artificial islands practical (assuming they don't sink under their own weight). A BFR will only require a launch pad, making platforms far cheaper than an island.

And you can built a platform high enough above the ocean to clear the highest storm surges you can reasonably expect, thus protecting the facility from the most debilitating potential hit it could take from a hurricane.

IMHO, you can more easily design a platform that can withstand 150 mph winds than you can one that won't wash away under a 35-foot storm surge...  :)
Title: Re: Where will BFR launch from?
Post by: Coastal Ron on 05/31/2016 10:18 pm
Airports require a lot of real estate, making artificial islands practical (assuming they don't sink under their own weight). A BFR will only require a launch pad, making platforms far cheaper than an island.

As I understand it the facility will be for both launching and landing, which means some open space between the two too.
Title: Re: Where will BFR launch from?
Post by: bstrong on 06/02/2016 06:32 pm
Interesting article by James Dean:

http://www.floridatoday.com/story/tech/science/space/2016/06/01/ksc-offers-land-launch-pads-other-projects/85198106/

Quote
KSC’s master plan carves out room for two more vertical launch complexes, numbered 48 and 49, that bookend the center’s two major pads, 39A and 39B.

Sounds like they are thinking about small launchers, but it also says:

Quote
“We’re prepared for whatever comes our way,” said Engler.
Title: Re: Where will BFR launch from?
Post by: tea monster on 06/02/2016 07:00 pm
It's obvious that a BFR will launch from a BFLP  ::)
Title: Re: Where will BFR launch from?
Post by: RedLineTrain on 06/02/2016 11:01 pm
One fly in the ointment for a platform off the coast of KSC is that other rockets would overfly it.
Title: Re: Where will BFR launch from?
Post by: groundbound on 06/02/2016 11:29 pm

Talk about using a stick of dynamite when a letter opener will suffice...

Especially when self ferry is more technologically feasible. At this point it is approaching "proven technology." After all, what is an F9 launch now if not a self ferry to ASDS with a satellite in orbit as a byproduct.
Title: Re: Where will BFR launch from?
Post by: philw1776 on 06/03/2016 03:29 pm
One fly in the ointment for a platform off the coast of KSC is that other rockets would overfly it.

Not a problem with Musk's railgun defense shield on ASDS V2

http://nextbigfuture.com/2016/06/navies-will-likely-need-to-start-with.html
Title: Re: Where will BFR launch from?
Post by: Ludus on 06/03/2016 08:02 pm
Just thought of a new T-Shirt inspired by Occupy Mars and another current slogan.

The T-Shirt shows the sequence of Mars being terraformed that SpaceX uses but adds a mirror sequence showing that Mars was once more earth like in the past.

So it's Mars Green to Red and then back to Green again.

The caption is "Make Mars Great Again" :)
Title: Re: Where will BFR launch from?
Post by: Syrinx on 06/03/2016 09:29 pm
The caption is "Make Mars Great Again" :)

Where can I send my money?
Title: Re: Where will BFR launch from?
Post by: guckyfan on 06/04/2016 06:46 am
LC 39D  would be my bet. https://www.fbo.gov/index?s=opportunity&mode=form&id=70425241dfbf865f51d55559c3844c89&tab=core&_cview=0

Yes. I was always hesitant to think of the Cape because of the restrictions there. But it may serve well for the initial period which may last longer than a decade. They should be able to do 3-5 Mars missions requiring 20 launches from there.
Title: Re: Where will BFR launch from?
Post by: The Amazing Catstronaut on 06/04/2016 01:20 pm
LC 39D  would be my bet. https://www.fbo.gov/index?s=opportunity&mode=form&id=70425241dfbf865f51d55559c3844c89&tab=core&_cview=0

Yes. I was always hesitant to think of the Cape because of the restrictions there. But it may serve well for the initial period which may last longer than a decade. They should be able to do 3-5 Mars missions requiring 20 launches from there.


They're certainly comfortable about shifting pads around, or having pads which do not possess a large amount of utilisation.
Title: Re: Where will BFR launch from?
Post by: ThereIWas3 on 06/04/2016 02:39 pm
And you can built a platform high enough above the ocean to clear the highest storm surges you can reasonably expect, thus protecting the facility from the most debilitating potential hit it could take from a hurricane.

But how would you lift the monster BFR up there?

Perhaps a floating barge that both delivers the BFR to the launch point and serves as the launch platform.  With the size Elon is talking about, I do not think they can use their current horizontal integration methods, and any transporting of the assembled vehicle (like was done for Apollo and Shuttle) seems full of problems.

Combine that with the need to launch very close to where it is manufactured.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 06/04/2016 03:07 pm
And you can built a platform high enough above the ocean to clear the highest storm surges you can reasonably expect, thus protecting the facility from the most debilitating potential hit it could take from a hurricane.

But how would you lift the monster BFR up there?

Perhaps a floating barge that both delivers the BFR to the launch point and serves as the launch platform.  With the size Elon is talking about, I do not think they can use their current horizontal integration methods, and any transporting of the assembled vehicle (like was done for Apollo and Shuttle) seems full of problems.

Combine that with the need to launch very close to where it is manufactured.

Unlike Shuttle and SLS, the BFRs themselves will be moved entirely unfueled.  (It's the weight of the fully fueled solid rocket motors that makes moving the SLS, and made moving the Shuttle, quite difficult.)  That makes the total weight of the rocket being hauled to the platforms relatively easily handled.

I envision an offshore launch platform that is serviced by a causeway/bridge.  If that bridge is three miles long, the grade to achieve a 50-foot platform height above sea level, for example, is easily handled by standard locomotive-based rail systems, such as the one that will pull Falcon Heavies from the crawlerway level up to the pad level at 39A.

I will also note that the base pad level at 39A is as high above sea level as any platform I'd envision SpaceX would build to launch BFRs, and Saturns, Shuttles, Falcons and SLSes have been, or will be, quite capable of climbing to the top of the pad structures at LC-39.  So, it's not only not a problem to overcome in the future, it's an issue that's been resolved for more than 50 years.
Title: Re: Where will BFR launch from?
Post by: pobermanns on 06/04/2016 03:12 pm
Kansai International Airport (https://en.wikipedia.org/wiki/Kansai_International_Airport) near Osaka, Japan, was built on an artificial island 4x2.5 km, about 3km off shore, in a water depth of 60 ft.  It was designed to handle earthquakes and tidal surges of 10 ft.   I watched a documentary on it, and I think they basically paid off the fishing interests.

The major problem they have had is that the tremendous weight is compressing the seabed faster than expected and the whole thing is sinking.


Airports require a lot of real estate, making artificial islands practical (assuming they don't sink under their own weight). A BFR will only require a launch pad, making platforms far cheaper than an island.

And you can built a platform high enough above the ocean to clear the highest storm surges you can reasonably expect, thus protecting the facility from the most debilitating potential hit it could take from a hurricane.

IMHO, you can more easily design a platform that can withstand 150 mph winds than you can one that won't wash away under a 35-foot storm surge...  :)

Agreed. And building an artificial island would be orders-of-magnitude more expensive than platforms. Heck, EM might be able to pick up a couple used platforms from played-out oil wells.

Why does it have to be much more complicated than something like this? (sorry for the really crude graphics - don't own a good graphics program, nor have the talent to use it)
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 06/04/2016 03:16 pm
I like the idea, but operationally speaking, I don't think they'll ever have their landing pad that close to their launch pad.  If you have an RUD upon landing, you'd rather not have any big kaboomy goodness going on near your fuel and LOX tanks and feed lines, thank-you-very-much... ;)
Title: Re: Where will BFR launch from?
Post by: pobermanns on 06/04/2016 03:26 pm
I like the idea, but operationally speaking, I don't think they'll ever have their landing pad that close to their launch pad.  If you have an RUD upon landing, you'd rather not have any big kaboomy goodness going on near your fuel and LOX tanks and feed lines, thank-you-very-much... ;)

Yeah, I had that idea too, but my non-artist skills kind of limit me. I'd think that the connecting causeway could be several times longer.

And nothing in this precludes your idea of a 3-mile causeway to the beach. I like that, too. For mine, I'm just thinking that if you have to have the launch site far offshore, it would be cheaper to bring in new rockets by ship. After all, EM might be a billionaire but he doesn't have infinitely deep pockets.

"A billion here, a billion there, pretty soon, you're talking real money." - Sen. Everett Dirksen
Title: Re: Where will BFR launch from?
Post by: mlindner on 06/04/2016 05:06 pm
BFR is obviously launching from Boca Chica. There's no other real possibility. That's the whole reason they built it is to get away from other range controls.
Title: Re: Where will BFR launch from?
Post by: JBF on 06/04/2016 06:00 pm
BFR is obviously launching from Boca Chica. There's no other real possibility. That's the whole reason they built it is to get away from other range controls.

What they are building in Boca Chica is nowhere close in size to what they will need for MCT.
Title: Re: Where will BFR launch from?
Post by: ThereIWas3 on 06/04/2016 06:23 pm
Since SpaceX launchers are fueled on the pad, then an offshore launch pad has to have facilities for that as well.   Refrigerated LOX pipes from shore 3 km long?   Or floating tank farm on barges just adjacent?

The idea of a 3 km causeway that rises 50 ft in the air is not out of the question; I have driven over bridges that do that.  The Chesapeake Bay Bridge/Tunnel is like that in places, and they are common in Florida.  It would be interesting to see the engineering considerations for something like that which can also handle the blast effects of repeated BFR launchings.  With access for maintenance...

Heinlein would have his really big ships just float in the water and launch from there, ("Time for the stars") but he never addressed the corrosion problems.  :)
Title: Re: Where will BFR launch from?
Post by: gospacex on 06/04/2016 06:47 pm
How much $$$ would this causeway of yours require?
Title: Re: Where will BFR launch from?
Post by: The Amazing Catstronaut on 06/04/2016 06:51 pm
I feel designing a drone launch pad doubling as a heavily armoured tanker capable of fully autonomous launch operations for the world's biggest launch vehicle in history is going to take a while.  :D More likely (to my mind) SpaceX would focus on getting individual elements of that capability cracked first. Grow accustomed to launch automation, feel confident launching BFR sticks, experiment with falcon droneship flyback. Don't try to go all in on the first shot. They can afford to do that with BFR itself because it builds on a lot of preexisting capabilities - this proposal suffers from less of a learning curve and more of a learning cliff - they need a gentler gradient if they're going to get there, and that gradient probably won't fit the timescale.

BFR will initially go skyward from KerbalKennedy Space Centre more likely than not - evacuating Boca Chica seems somewhat mean-minded.
Title: Re: Where will BFR launch from?
Post by: Ludus on 06/04/2016 09:49 pm
Since SpaceX launchers are fueled on the pad, then an offshore launch pad has to have facilities for that as well.   Refrigerated LOX pipes from shore 3 km long?   Or floating tank farm on barges just adjacent?

The idea of a 3 km causeway that rises 50 ft in the air is not out of the question; I have driven over bridges that do that.  The Chesapeake Bay Bridge/Tunnel is like that in places, and they are common in Florida.  It would be interesting to see the engineering considerations for something like that which can also handle the blast effects of repeated BFR launchings.  With access for maintenance...

Heinlein would have his really big ships just float in the water and launch from there, ("Time for the stars") but he never addressed the corrosion problems.  :)

I'd think ordinary gas pipelines underwater for oxygen and methane, power and fiber optic cables too. The oxygen and methane would be liquified at the platform.

I think a platform and pipelines could be built within the time and budget constraints but an elevated causeway would be way more expensive and difficult. I think a horizontal assembly building on the shore like a boathouse with the floor being a barge that takes the rocket out to the launch platform might work. Once built, a reasonably automated launch system wouldn't require very many workers to be on the platform so there's little reason to build a causeway that breaks the budget.

If returning stages always landed on an ASDS whether out to sea or near the launch site there could be a consistent process for it to return to the horizontal assembly building and be off loaded right there.
Title: Re: Where will BFR launch from?
Post by: Ludus on 06/04/2016 10:04 pm
I feel designing a drone launch pad doubling as a heavily armoured tanker capable of fully autonomous launch operations for the world's biggest launch vehicle in history is going to take a while.  :D More likely (to my mind) SpaceX would focus on getting individual elements of that capability cracked first. Grow accustomed to launch automation, feel confident launching BFR sticks, experiment with falcon droneship flyback. Don't try to go all in on the first shot. They can afford to do that with BFR itself because it builds of a lot of preexisting capabilities - this proposal suffers from less of a learning curve and more of a learning cliff - they need a gentler gradient if they're going to get there, and that gradient probably won't fit the timescale.

BFR will initially go skyward from KerbalKennedy Space Centre more likely than not - evacuating Boca Chica seems somewhat mean-minded.

Building another KSC pad like 39d or whatever designation always seemed like the most practical approach. There aren't a lot of new issues either technical or regulatory as there would be for a sea platform or Boca Chica. They'd just have to start making progress very soon to have it ready for 2022. I suppose they won't even announce the details of the rocket until September but this ought to become a public discussion after that.
Title: Re: Where will BFR launch from?
Post by: philw1776 on 06/04/2016 11:54 pm
SX optimizes for cost.
Therefore in the short run, no expensive causeway to an offshore platform and no expensive pipeline for propellant.  Stuff will get barged out and back the few Km to the platform.  Takes longer, costs a lot less up front.

In the LONG run when colonization cargo and personnel flights increase, a decade or so after initial missions, a causeway will be built along with alternate launch sites so that hurricane weather doesn't screw a synod.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/05/2016 01:14 am
Since SpaceX launchers are fueled on the pad, then an offshore launch pad has to have facilities for that as well.   Refrigerated LOX pipes from shore 3 km long?   Or floating tank farm on barges just adjacent?

The idea of a 3 km causeway that rises 50 ft in the air is not out of the question; I have driven over bridges that do that.  The Chesapeake Bay Bridge/Tunnel is like that in places, and they are common in Florida.  It would be interesting to see the engineering considerations for something like that which can also handle the blast effects of repeated BFR launchings.  With access for maintenance...

Heinlein would have his really big ships just float in the water and launch from there, ("Time for the stars") but he never addressed the corrosion problems.  :)

I'd think ordinary gas pipelines underwater for oxygen and methane, power and fiber optic cables too. The oxygen and methane would be liquified at the platform.
...
Might as well just extract the oxygen at the platform as well, if you're going to bother liquifying it (which is the main thing you have to do to extract it.
Title: Re: Where will BFR launch from?
Post by: Zed_Noir on 06/05/2016 02:08 am
...
In the LONG run when colonization cargo and personnel flights increase, a decade or so after initial missions, a causeway will be built along with alternate launch sites so that hurricane weather doesn't screw a synod.

Don't think that multiple launch sites on land is likely IMO. Including coastal sites reach by causeways, bridges or barges. Since there will only likely to be one LV assembly facility. Which will shipped out the BFRs in barges or ships to a launch site. After all how do you move a 15+ meter diameter LV core on roads and railways from a port to a launch site.

If SpaceX wants multiple launch sites for the BFR. They might be better off just deploying ships that can transport BFRs and ships that can launch BFRs in the Ocean. Which in theory could allow the salvo launch of several BFRs from ocean platforms during a short period of time for mass propellant deliveries to LEO.

In any case more details on the BFR, BFS & MCT should come out at the IAC (https://www.iac2016.org/) in September from Musk.

Title: Re: Where will BFR launch from?
Post by: Ludus on 06/05/2016 04:07 am
Since SpaceX launchers are fueled on the pad, then an offshore launch pad has to have facilities for that as well.   Refrigerated LOX pipes from shore 3 km long?   Or floating tank farm on barges just adjacent?

The idea of a 3 km causeway that rises 50 ft in the air is not out of the question; I have driven over bridges that do that.  The Chesapeake Bay Bridge/Tunnel is like that in places, and they are common in Florida.  It would be interesting to see the engineering considerations for something like that which can also handle the blast effects of repeated BFR launchings.  With access for maintenance...

Heinlein would have his really big ships just float in the water and launch from there, ("Time for the stars") but he never addressed the corrosion problems.  :)

I'd think ordinary gas pipelines underwater for oxygen and methane, power and fiber optic cables too. The oxygen and methane would be liquified at the platform.
...
Might as well just extract the oxygen at the platform as well, if you're going to bother liquifying it (which is the main thing you have to do to extract it.

I just googled it and learned something about liquid oxygen. I guess at most one pipeline and facilities something like a LNG terminal.
Title: Re: Where will BFR launch from?
Post by: biosehnsucht on 06/05/2016 08:17 am
Hell with enough power (floating solar, wind farms, tidal?) you could even manufacture CH4 there the same way you do at Mars... And as you process the water to get the Hydrogen component, you could also process out the lithium that was in the sea water and ship it to Tesla... ;)
Title: Re: Where will BFR launch from?
Post by: philw1776 on 06/05/2016 12:59 pm
...
In the LONG run when colonization cargo and personnel flights increase, a decade or so after initial missions, a causeway will be built along with alternate launch sites so that hurricane weather doesn't screw a synod.

Don't think that multiple launch sites on land is likely IMO. Including coastal sites reach by causeways, bridges or barges. Since there will only likely to be one LV assembly facility. Which will shipped out the BFRs in barges or ships to a launch site. After all how do you move a 15+ meter diameter LV core on roads and railways from a port to a launch site.

If SpaceX wants multiple launch sites for the BFR. They might be better off just deploying ships that can transport BFRs and ships that can launch BFRs in the Ocean. Which in theory could allow the salvo launch of several BFRs from ocean platforms during a short period of time for mass propellant deliveries to LEO.

In any case more details on the BFR, BFS & MCT should come out at the IAC (https://www.iac2016.org/) in September from Musk.

???

I never said multiple launch sites on land, or any sites on land.

Multiple launch sites in shallow waters away from population centers complaining about the noise from a much larger than Saturn V AND with far more frequent launches
Title: Re: Where will BFR launch from?
Post by: Jcc on 06/05/2016 01:23 pm
I feel designing a drone launch pad doubling as a heavily armoured tanker capable of fully autonomous launch operations for the world's biggest launch vehicle in history is going to take a while.  :D More likely (to my mind) SpaceX would focus on getting individual elements of that capability cracked first. Grow accustomed to launch automation, feel confident launching BFR sticks, experiment with falcon droneship flyback. Don't try to go all in on the first shot. They can afford to do that with BFR itself because it builds of a lot of preexisting capabilities - this proposal suffers from less of a learning curve and more of a learning cliff - they need a gentler gradient if they're going to get there, and that gradient probably won't fit the timescale.

BFR will initially go skyward from KerbalKennedy Space Centre more likely than not - evacuating Boca Chica seems somewhat mean-minded.

Building another KSC pad like 39d or whatever designation always seemed like the most practical approach. There aren't a lot of new issues either technical or regulatory as there would be for a sea platform or Boca Chica. They'd just have to start making progress very soon to have it ready for 2022. I suppose they won't even announce the details of the rocket until September but this ought to become a public discussion after that.

I think a new pad at KSC would be a good location too, but they would have to modernize the range control, to be able to support daily launches (SpaceX, ULA, BO, SLS, and others). They can't be waiting days for the range equipment to be reconfigured for a different launch vehicle, or range downtime due to equipment failure or maintenance.
Title: Re: Where will BFR launch from?
Post by: Lar on 06/05/2016 02:19 pm
How much consideration to noise and wave action has really been given when talking about massive offshore sites

If this is what they had to do for a F9 first stage landing site...

https://twitter.com/talulahriley/status/320422298618302464

How do you hold off Greenpeace?

(https://pbs.twimg.com/media/BHJeYgeCEAAx-YG.jpg:large)
Title: Re: Where will BFR launch from?
Post by: eywflyer on 06/05/2016 02:40 pm
Johnston Atoll is US territory that's fairly close to the equator and has no population within hundreds of miles in any direction (750 nm SW of Hawaii). It was USAF for many years but closed around 2004 and is now a National Wildlife Refuge. Unlikely site due to extremely high logistical costs and current NWR status, but if remoteness from any populated area is a primary concern there aren't many places in the world more remote than Johnston.

I saw the Florida Keys mentioned up thread - I lived in Key West for several years and would think a launch site in the Keys is extremely unlikely. Multiple wildlife refuges and marine sanctuaries there, and the locals are very environmentally focused.
Title: Re: Where will BFR launch from?
Post by: joek on 06/05/2016 03:43 pm
I think a new pad at KSC would be a good location too, but they would have to modernize the range control, to be able to support daily launches (SpaceX, ULA, BO, SLS, and others). They can't be waiting days for the range equipment to be reconfigured for a different launch vehicle, or range downtime due to equipment failure or maintenance.

The good news is that the RACE (http://thomas.loc.gov/cgi-bin/query/z?c112:H.R.4401:) act allows for non-Federal contributions for range modernization.  That does not mean it will happen (still a number of limitations and caveats), but if a commercial provider is willing to contribute funds for range modernization, it is no longer disallowed as it was previously.
Title: Re: Where will BFR launch from?
Post by: gospacex on 06/05/2016 05:43 pm
Looking at the map, some 40 miles north of Boca Chica there are places with absolutely no towns/villages/anything for 10 miles around: Parde Island. Maybe SpaceX can build there.
Title: Re: Where will BFR launch from?
Post by: docmordrid on 06/05/2016 06:11 pm
1,289 square miles of that "empty area" area North of Boca Chica and South of Corpus Christi is part of the King Ranch.
Title: Re: Where will BFR launch from?
Post by: llanitedave on 06/05/2016 10:08 pm
1,289 square miles of that "empty area" area North of Boca Chica and South of Corpus Christi is part of the King Ranch.

May 24, 2016, I proposed the same thing in Reply #173 (https://forum.nasaspaceflight.com/index.php?topic=39162.msg1538622#msg1538622) of this very thread.
Title: Re: Where will BFR launch from?
Post by: oiorionsbelt on 06/06/2016 12:07 am
"If this works, I'm treating myself to a volcano lair. It's time." Elon Musk
https://twitter.com/elonmusk/status/588144086755999744?lang=en
Title: Re: Where will BFR launch from?
Post by: TheTraveller on 06/10/2016 09:34 pm
"If this works, I'm treating myself to a volcano lair. It's time." Elon Musk
https://twitter.com/elonmusk/status/588144086755999744?lang=en

Yup!

SpaceX flight 1 to Mars leaving in 1 hour. All passengers please proceed to security.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/11/2016 05:54 pm
After thinking about it, I now think that BFR will first launch from some place that's probably not appropriate for hourly launches.

Like, sure, they want to do colonization, but those trips will only really start in force like a decade after the first mission. They're not going to be launching 10,000 BFRs a year in 2030.

Let's say the progress is like this:

2018: ground is broken on first launch site.
2020: first GSE integration tests
2021: first BFR test launches
2022: first MCT flight to Mars (1 BFS launch, 1-3 refueling launches)
2024: first crewed MCT flight to Mars (1 BFS, 3 refueling launches)
2026 second crewed MCT flight, twice as many launches (8, 2 MCTs).
2028, third crewed MCT flight, 12 total BFR/refuel launches (3 MCTs).

In between, you could conceivably be launching cargo. But not until 2030, about 12 years after ground is broken, will you really start getting more than 12 launches per year.

It might make sense just to say, "screw it, let's just build at Boca Chica or undeveloped Kennedy land" and live with a 12-flight-per-year limit at first, until you can negotiate a higher launch rate or build somewhere that can tolerate like a billion kajillion launches per year, perhaps on some artificial island with a causeway, etc.

SpaceX seems serious about launching MCT to Mars in a ridiculously short period of time (2022 uncrewed, that's just 6 years!). And they don't seem to mind building stuff that might only last for a few years as long as it's cheap. So I think these grander plans will just have to wait until later because they simply won't be ready in time for when they want to start flying.

...and no doubt they'll have multiple BFR launch sites eventually. Probably not /dozens/ of launch sites, but more than one.


Anyway, I can totally see them picking Boca Chica or someplace like that and just building it quickly and cheaply. Get 'er done
Title: Re: Where will BFR launch from?
Post by: yoram on 06/11/2016 06:50 pm
...and no doubt they'll have multiple BFR launch sites eventually. Probably not /dozens/ of launch sites, but more than one.

Wouldn't that need multiple factories too? Does not seem cheap.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/11/2016 06:55 pm
...and no doubt they'll have multiple BFR launch sites eventually. Probably not /dozens/ of launch sites, but more than one.

Wouldn't that need multiple factories too? Does not seem cheap.
Nah. It's possible they could self-ferry and/or be transported on boats.
Title: Re: Where will BFR launch from?
Post by: guckyfan on 06/11/2016 07:15 pm
...and no doubt they'll have multiple BFR launch sites eventually. Probably not /dozens/ of launch sites, but more than one.

Wouldn't that need multiple factories too? Does not seem cheap.
Nah. It's possible they could self-ferry and/or be transported on boats.

Even if transport is expensive, it needs to be done only once for at least 100 launches for BFR. A second stage can self ferry.
Title: Re: Where will BFR launch from?
Post by: Blackjax on 06/14/2016 11:42 pm
I was reading this and it made me go hmmm...

http://www.parabolicarc.com/2016/06/14/zealand-reach-technology-safeguard-agreement-rocket-lab-launches/

I wonder just how much this agreement opens up possibilities.
Title: Re: Where will BFR launch from?
Post by: Ludus on 06/15/2016 01:56 am
I was reading this and it made me go hmmm...

http://www.parabolicarc.com/2016/06/14/zealand-reach-technology-safeguard-agreement-rocket-lab-launches/

I wonder just how much this agreement opens up possibilities.

Well, NZ launch sites would be further from the Equator than Florida or S.Texas and lack support infrastructure. Hard to picture the government of NZ spending a lot on it.
Title: Re: Where will BFR launch from?
Post by: bstrong on 06/16/2016 09:34 pm
I was reading this and it made me go hmmm...

http://www.parabolicarc.com/2016/06/14/zealand-reach-technology-safeguard-agreement-rocket-lab-launches/

I wonder just how much this agreement opens up possibilities.

Well, NZ launch sites would be further from the Equator than Florida or S.Texas and lack support infrastructure. Hard to picture the government of NZ spending a lot on it.

However, this does disprove the assertion that comes up frequently in this discussion that "you can't launch US rockets from another country because ITAR". Presumably it would be possible for another country closer to the equator to come to a similar agreement.
Title: Re: Where will BFR launch from?
Post by: Kansan52 on 06/16/2016 09:59 pm
However, this does disprove the assertion that comes up frequently in this discussion that "you can't launch US rockets from another country because ITAR". Presumably it would be possible for another country closer to the equator to come to a similar agreement.

Not really. It's a New Zealand company reaching an agreement with the New Zealand government.
Title: Re: Where will BFR launch from?
Post by: bstrong on 06/17/2016 12:35 pm
However, this does disprove the assertion that comes up frequently in this discussion that "you can't launch US rockets from another country because ITAR". Presumably it would be possible for another country closer to the equator to come to a similar agreement.

Not really. It's a New Zealand company reaching an agreement with the New Zealand government.

Actually, according to https://rocketlabusa.com/about-us/

Quote
Rocket Lab is a US corporation with a New Zealand subsidiary...

And their job postings all have this notice:

Quote
For security reasons background checks will be undertaken prior to any employment offers being made to an applicant.  These checks will include nationality checks as it is a requirement of this position that you be eligible to access equipment and data regulated by the United States’ International Traffic in Arms Regulations.

And I recall reading that they planned to start doing engineering in their US office, but I can't find the reference now. Not exactly the same situation as SpaceX, but enough similarities that I'm less convinced that SpaceX couldn't launch in another country.



Title: Re: Where will BFR launch from?
Post by: Kansan52 on 06/17/2016 04:04 pm
Yep.
Title: Re: Where will BFR launch from?
Post by: CNYMike on 06/17/2016 04:57 pm
It's too big for 39A, so that location is out.

Pardon my ignorance, what makes it too big for 39A? Is it a range safety concern with that much fuel/oxidizer in one spot? Insufficient flame trench? Too big for the transporter/erector? Blockhouse not far enough away?

Pad 39A was built to handle a maximum thrust of 12.5 Mlb at takeoff (Saturn V was 7.65 Mlb at takeoff, Nova-class launcher would have been around 12 Mlb), while BFR is said to be around 15 Mlb thrust -- double that of a Saturn V.

And so the pad would have to be even bigger than LC39.  This is nothing to sneeze at.  The LC39 pads have a ridiculous amount of concrete in them, and the BFR pad would need even more.  Now, I won't deny being a SpaceX skeptic and therefore, somewhat biased.  But if there isn't word of SpaceX buying that much concrete, it does get hard where the BFR will be launched from, and not a lot of time if he's going meet his own deadline of a launch window in 2024.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/17/2016 05:00 pm
It's too big for 39A, so that location is out.

Pardon my ignorance, what makes it too big for 39A? Is it a range safety concern with that much fuel/oxidizer in one spot? Insufficient flame trench? Too big for the transporter/erector? Blockhouse not far enough away?

Pad 39A was built to handle a maximum thrust of 12.5 Mlb at takeoff (Saturn V was 7.65 Mlb at takeoff, Nova-class launcher would have been around 12 Mlb), while BFR is said to be around 15 Mlb thrust -- double that of a Saturn V.

And so the pad would have to be even bigger than LC39.  This is nothing to sneeze at.  The LC39 pads have a ridiculous amount of concrete in them, and the BFR pad would need even more.  Now, I won't deny being a SpaceX skeptic and therefore, somewhat biased.  But if there isn't word of SpaceX buying that much concrete, it does get hard where the BFR will be launched from, and not a lot of time if he's going meet his own deadline of a launch window in 2024.
The BFR's pad may simply not use as much concrete due to a different design. Also, they tend to do a lot of "just in time" work.

Boca Chica is a possible first launch site for BFR. They don't have approval for something like BFR, yet, but it's possible they would receive it.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 06/17/2016 05:01 pm
It's too big for 39A, so that location is out.

Pardon my ignorance, what makes it too big for 39A? Is it a range safety concern with that much fuel/oxidizer in one spot? Insufficient flame trench? Too big for the transporter/erector? Blockhouse not far enough away?

Pad 39A was built to handle a maximum thrust of 12.5 Mlb at takeoff (Saturn V was 7.65 Mlb at takeoff, Nova-class launcher would have been around 12 Mlb), while BFR is said to be around 15 Mlb thrust -- double that of a Saturn V.

And so the pad would have to be even bigger than LC39.  This is nothing to sneeze at.  The LC39 pads have a ridiculous amount of concrete in them, and the BFR pad would need even more.  Now, I won't deny being a SpaceX skeptic and therefore, somewhat biased.  But if there isn't word of SpaceX buying that much concrete, it does get hard where the BFR will be launched from, and not a lot of time if he's going meet his own deadline of a launch window in 2024.

Ah, but an offshore launch platform could be made mostly of steel.  Not huge amounts of concrete in an offshore drilling rig, which is the closest analog to an offshore BFR launch platform...
Title: Re: Where will BFR launch from?
Post by: CNYMike on 06/17/2016 05:01 pm
....It's too big for 39A, so that location is out....

Not only that, but all the photo and artwork for the modification to 39A show it's pretty clearly designed for Falcon 9 and Falcon 9 heavy.  The assembly building is right next to the pad and you wouldn't want it to that close to something bigger than a Saturn V.  That's why VAB is a mile from the pads. 
Title: Re: Where will BFR launch from?
Post by: CNYMike on 06/17/2016 05:03 pm
Ah, but an offshore launch platform could be made mostly of steel.  Not huge amounts of concrete in an offshore drilling rig, which is the closest analog to an offshore BFR launch platform...

True, but it would still be one heck of a structure for supporting the weight of a fully fueled BFR, and some shipyard somewhere is going to get the contract to build it.  Again, not something that could be hidden. 
Title: Re: Where will BFR launch from?
Post by: docmordrid on 06/17/2016 05:12 pm
The KSC Master Plan shows a reserved spot for a commercial 39D (39C now being a  small launcher pad cosited with 39B) north of the current pads. Far enough away?
Title: Re: Where will BFR launch from?
Post by: rcoppola on 06/17/2016 06:24 pm
If this beast remains as has been hinted, overtly said (L2) and publicly theorized, I'm having a difficult time envisioning a launch from Boca Chica. You'd shake the entire region back into the gulf.  (only half joking)

We'll learn more at the announcement in September as this will be one of the first questions asked. But this is not just a launch pad. It's also manufacturing, integration, cargo/passenger processing/loading/boarding, landing, etc, etc, etc, etc...

KSC doesn't have room for something at this scale. Not anymore. Not with SLS and the current KSC Multi-user master plan. But there must be ongoing conversations with someone, somewhere...

This is not just a logistical question but a rather large and complicated  political one as well. The sheer scale of this will need some very hefty political and economic influence at the local, state and federal level that will make Boca Chica look like child's play. And I'm not even touching the EIS process. Let alone the local and state infrastructure investments they'll need. IIRC, they were playing a group of states against each other for quite a long time before the selection process officially concluded with TX.

Maybe the Presidential Transition Team will recommend scrapping the Multi-User concept and just give them the keys to KSC. A modified 39B for BFR,  proposed 39D&C for landing, VAB dismantled/modified, new NASA HQ subleased and used for passenger living/training quarters and general offices, relinquish LC-40 for others to share. Yeh, not going to happen. So where's a 1950s version of pre-KSC lying around?
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/17/2016 06:33 pm
It's 3 or 4 times the thrust of Falcon Heavy. If Boca Chica can handle Falcon Heavy, it doesn't seem crazy that it might handle a few BFR launches.

Not hourly launches, of course, but for initial capability it may be a good choice.
Title: Re: Where will BFR launch from?
Post by: Todd Martin on 06/17/2016 06:53 pm
According to Elon, sound suppression is best achieved by placing the source of the noise inside an island's dormant volcano.  Consider the American Samoa's.  This U.S. territory is only 13 degrees, 35 minutes South of the Equator compared to 26 degrees North for Boca Chica TX.  Tutuila is a dormant volcano island with an international airport and a deep harbor.
Title: Re: Where will BFR launch from?
Post by: RedLineTrain on 06/17/2016 06:55 pm
We don't know for sure how big it will be.  Even the information in L2 could change.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/17/2016 06:59 pm
We don't know for sure how big it will be.  Even the information in L2 could change.
Technically true for anything happening in the future, but of all the things we know about BFR, the total thrust (about 15 million lbf) has the most corroboration over time, people, and contexts.
Title: Re: Where will BFR launch from?
Post by: rcoppola on 06/17/2016 07:09 pm
It's 3 or 4 times the thrust of Falcon Heavy. If Boca Chica can handle Falcon Heavy, it doesn't seem crazy that it might handle a few BFR launches.

Not hourly launches, of course, but for initial capability it may be a good choice.
It can handle the FH because it's being built to handle it. This area is not being built to handle anything to the scale of BFR. Not the pad, not the tanks, not the TE, not the hangars, etc.. And certainly you're not moving the town another x% safe zone further away. Besides, no way are they going to build a temp anything for this. The scale is too big on every level. As you well know, this is not replacing TELs every 6-8 months, or modifying launch plates under tents. They'll select one place and build/test in stages there. It's way too politically, economically, environmentally unreasonable to do otherwise. IMHO.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/17/2016 07:11 pm
According to Elon, sound suppression is best achieved by placing the source of the noise inside an island's dormant volcano.  Consider the American Samoa's.  This U.S. territory is only 13 degrees, 35 minutes South of the Equator compared to 26 degrees North for Boca Chica TX.  Tutuila is a dormant volcano island with an international airport and a deep harbor.

What's the point of holding in noise if you're in the middle of the ocean? If anything, you want to radiate it to help dissipate the acoustic energy.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/17/2016 07:13 pm
It's 3 or 4 times the thrust of Falcon Heavy. If Boca Chica can handle Falcon Heavy, it doesn't seem crazy that it might handle a few BFR launches.

Not hourly launches, of course, but for initial capability it may be a good choice.
It can handle the FH because it's being built to handle it. This area is not being built to handle anything to the scale of BFR. Not the pad,...
Are you certain the pad wouldn't work? I see no evidence that definitively says it wouldn't and couldn't.
Quote
Besides, no way are they going to build a temp anything for this. ...
Totally disagree. SpaceX has done temporary stuff all the time.

SpaceX doesn't build a reinforced VAB, they built a cheap HIF like a pole-barn (well inside the worst-case blast radius of a Falcon Heavy and unable to withstand a direct hit by a large hurricane) on top of a crawlerway that they're leasing for a temporary length of time. SpaceX plans change often, and building stuff super cheap is how they're able to afford it.
Title: Re: Where will BFR launch from?
Post by: rcoppola on 06/17/2016 07:33 pm
It's 3 or 4 times the thrust of Falcon Heavy. If Boca Chica can handle Falcon Heavy, it doesn't seem crazy that it might handle a few BFR launches.

Not hourly launches, of course, but for initial capability it may be a good choice.
It can handle the FH because it's being built to handle it. This area is not being built to handle anything to the scale of BFR. Not the pad,...
Are you certain the pad wouldn't work? I see no evidence that definitively says it wouldn't and couldn't.
Quote
Besides, no way are they going to build a temp anything for this. ...
Totally disagree. SpaceX has done temporary stuff all the time.

SpaceX doesn't build a reinforced VAB, they built a cheap HIF like a pole-barn on top of a crawlerway that they're leasing for a temporary length of time. SpaceX plans change often, and building stuff super cheap is how they're able to afford it.
Did I not include examples of how, yes, they change plans all the time? But are you seriously equating the scale of effort, time and money to make changes to F9/FH infrastructure with that of a BFR? Sorry, I am just not seeing it. But hey, that's ok. Nobody knows the plans for sure. So we'll see in due time where this nets out. I'd be more than happy to be wrong about this. I just don't think I am...for now.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/17/2016 07:41 pm
Proportionally, the change in thrust from Falcon 9 v1.0 to the current version of Falcon Heavy is actually /greater/ than the change in thrust from Falcon Heavy to BFR.

(Falcon Heavy):(F9v1.0) = 5.2.

(BFR):(Falcon Heavy) = 3 to 4, according to both Shotwell and Musk publicly.

So yeah, I /do/ think they could do something similar to what they're doing for Falcon Heavy, just on a larger scale. Just like how they did Falcon Heavy at a larger scale than Falcon 9. (The HIF is similar to the facility at LC40.)

I think it's instructive to take a step back and stop thinking about building/operating BFR the way NASA built/operated Saturn V or Shuttle. If SpaceX can get by with a structure like the HIF but a bit larger, then they will. And they'll do it on the cheap. Because that's the only way this is going to work.


SpaceX is going to do BFR like SpaceX, not like NASA.
Title: Re: Where will BFR launch from?
Post by: rcoppola on 06/17/2016 08:15 pm
Ok, well, not sure who mentioned anything about NASA, Saturn V or Shuttle. I know I didn't. And the thread is about where to launch it. I don't know where yet but IMO, it's not going to be from Boca Chica, which is what you and I currently disagree about. Which is fine.
Title: Re: Where will BFR launch from?
Post by: JasonAW3 on 06/17/2016 08:20 pm
According to Elon, sound suppression is best achieved by placing the source of the noise inside an island's dormant volcano.  Consider the American Samoa's.  This U.S. territory is only 13 degrees, 35 minutes South of the Equator compared to 26 degrees North for Boca Chica TX.  Tutuila is a dormant volcano island with an international airport and a deep harbor.

What's the point of holding in noise if you're in the middle of the ocean? If anything, you want to radiate it to help dissipate the acoustic energy.

      Part of the reason for dissipating the noise is the reflected shockwave that occurs when you launch a rocket. 

      This shockwave, for larger rockets, is typically powerful enough that it can tear apart a rocket.

      Smaller rockets, such as sounding rockets, can get away with this issue because they are typically within the shockwave zone for only fractions of a second, whereas larger rockets not only take a few seconds to get high enough that the shockwaves aren't an issue.

      This, and it helps prevent back blast from the reflected exhaust, are the main reason the water deluge system is activated seconds prior to the actual ignition of the rocket engines.  (And, of course, it helps dissipate gases and fuel build ups under the rocket prior to ignition).

      I figure Jim can correct me if I missed anything.
Title: Re: Where will BFR launch from?
Post by: JasonAW3 on 06/17/2016 08:26 pm
Ok, well, not sure who mentioned anything about NASA, Saturn V or Shuttle. I know I didn't. And the thread is about where to launch it. I don't know where yet but IMO, it's not going to be from Boca Chica, which is what you and I currently disagree about. Which is fine.

      I'm pretty sure that Boca Chica wouldn't really be capable of handling the launch of such a rocket, simply due to proximity of non SpaceX facilities and civilians.

      If the BFR goes boom, it's going to be on the scale of a small nuclear device.  (As I seem to remember, there was some debate as to whether or not the Saturn V pads were too close to the VAB, as an explosion from it would send shrapnel flying for miles).

     Something like a Falcon 9 blowing up at Boca Chica is far less of an issue than something the size of the Nova class rocket blowing up there.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/18/2016 12:58 am
Ok, well, not sure who mentioned anything about NASA, Saturn V or Shuttle. I know I didn't. And the thread is about where to launch it. I don't know where yet but IMO, it's not going to be from Boca Chica, which is what you and I currently disagree about. Which is fine.

      I'm pretty sure that Boca Chica wouldn't really be capable of handling the launch of such a rocket, simply due to proximity of non SpaceX facilities and civilians.

      If the BFR goes boom, it's going to be on the scale of a small nuclear device.  (As I seem to remember, there was some debate as to whether or not the Saturn V pads were too close to the VAB, as an explosion from it would send shrapnel flying for miles).

     Something like a Falcon 9 blowing up at Boca Chica is far less of an issue than something the size of the Nova class rocket blowing up there.
Falcon Heavy blowing up in Boca Chica is ALSO equivalent to a small nuclear device. Falcon Heavy, with a third the energy, has a blast radius only ~30% less than BFR would have.

You can't be "pretty sure" without doing analysis.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/18/2016 02:13 am
The Boca Chica launch site appears to be far enough away from the nearest residential areas for the dangers of BFR exploding on or near the pad present little risk of structural damage from overpressure or thermal radiation. Saturn V was estimates as equivalent to a .5 kt nuclear detonation, so BFR should be no bigger than 1.4 kt. Significant overpressure and thermal effects should extend only about 1km radius from the pad:

Other significant effects (including flying fragments or noise) might extend further.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 06/18/2016 04:18 am
I'd also like to note that comparisons between an exploding rocket -- particularly an exploding hydrocarbon/LOX rocket -- and a nuclear explosion are somewhat chimerical.

You can argue that the total energy released by an exploding Saturn V or BFR is of the same order as a small fission bomb.  But the time over which the energy is released is significantly longer for an exploding rocket than for a nuclear bomb.  Which has a lot of an impact (literally) on how devastating an overpressure wave develops.  The faster air is displaced, the greater the overpressure wave, the greater the damage in nearby areas.

The thermal radiation would be roughly equivalent, but again with a longer build-up.  A rocket generates a big light as it explodes, while a nuclear explosion generates a hyper-intense flash.  In the latter, the photon density along the shock front is a lot higher, for example.

This is not to say that an exploding BFR won't break windows ten miles away.  It's not going to set fire to buildings three to five miles away just from the heat/light flash, and totally flatten buildings within two to three miles from its overpressure wave, like a similar-power nuke would, though.

You don't want to be a mile or two away form a BFR explosion, sure.  But it's not like it would take a chunk the size of Galveston out of south Texas if it happened...
Title: Re: Where will BFR launch from?
Post by: darkenfast on 06/18/2016 07:25 am
You can't ignore the Mexican border.  If the launch of a rocket or possible explosions can cause unhealthy levels of sound or shock waves at a distance farther than the border, then Mexico will have a say in it.  It doesn't matter if there's nothing there, it is still another country's land and air-space and they have control over it. 
Title: Re: Where will BFR launch from?
Post by: cuddihy on 06/18/2016 02:04 pm
No, not unless the US and Mexico agree to it. I doubt current air travel treaties cover cross- border explosions.  Although depending on the whim of regulators, FAA could interpret its licensing procedures for commercial launch to include cross-border explosions on the ground...it'd be a reach, and liable to court scrutiny.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/18/2016 02:17 pm
So the blast radius from Falcon Heavy is only 30% less than BFR, but somehow isn't a problem whatsoever while for BFR is supposedly a showstopper according to armchair experts here...

Get your minds out of "BFR is just so BIIIIIG" and start doing actual analysis.
Title: Re: Where will BFR launch from?
Post by: philw1776 on 06/18/2016 02:55 pm
Boca Chica offshore is not very deep, ideal for a few Km offshore launch platform away from the populace, initially serviced and supplied by barges & hydrofoils.
Title: Re: Where will BFR launch from?
Post by: CNYMike on 06/18/2016 05:18 pm
So the blast radius from Falcon Heavy is only 30% less than BFR, but somehow isn't a problem whatsoever while for BFR is supposedly a showstopper according to armchair experts here...

Get your minds out of "BFR is just so BIIIIIG" and start doing actual analysis.

At LC39A, the assembly building for both the Falcon 9 and the Falcon 9 heavy is right at the bottom of the ramp up to the pad.  When LC39 was built for the Saturn V, the assembly building was put a mile from the pad.  The BFR is supposed to be bigger than the Saturn V.

So the point is a rocket bigger than a Saturn V should, logically, require facilities on the same scale.  And that scale of construction can't be hidden.  So where is it?
Title: Re: Where will BFR launch from?
Post by: Thorny on 06/18/2016 05:26 pm
When LC39 was built for the Saturn V, the assembly building was put a mile from the pad.

Actually, 3 1/2 miles between the VAB and Pad 39A.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/19/2016 12:45 am
So the blast radius from Falcon Heavy is only 30% less than BFR, but somehow isn't a problem whatsoever while for BFR is supposedly a showstopper according to armchair experts here...

Get your minds out of "BFR is just so BIIIIIG" and start doing actual analysis.

At LC39A, the assembly building for both the Falcon 9 and the Falcon 9 heavy is right at the bottom of the ramp up to the pad.  When LC39 was built for the Saturn V, the assembly building was put a mile from the pad.  The BFR is supposed to be bigger than the Saturn V.

So the point is a rocket bigger than a Saturn V should, logically, require facilities on the same scale.  And that scale of construction can't be hidden.  So where is it?

No. You're missing the point. My point is that the HIF is WITHIN the theoretical blast radius of a Falcon Heavy. The VAB is OUTSIDE the blast radius of a Saturn V (or Falcon Heavy or Nova or BFR).

SpaceX has a different opinion than NASA on whether it's better to build really expensive and hardened facilities or super cheap and easily replaced facilities. Based on that, I say that, logically, SpaceX will NOT be building a VAB or anything like it. They will be building something cheap and easily replaced. Something like the HIF but about twice as much volume (+/-50%).
Title: Re: Where will BFR launch from?
Post by: Nilof on 06/19/2016 02:54 pm
No. You're missing the point. My point is that the HIF is WITHIN the theoretical blast radius of a Falcon Heavy. The VAB is OUTSIDE the blast radius of a Saturn V (or Falcon Heavy or Nova or BFR).

...Are you sure about that? Looking at the N1 launch explosions, I'd expect the VAB to be in significant danger if the Saturn V ever exploded. The explosion on the second N1 launch delayed the Soviet lunar program by 18 months.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/19/2016 04:15 pm
No. You're missing the point. My point is that the HIF is WITHIN the theoretical blast radius of a Falcon Heavy. The VAB is OUTSIDE the blast radius of a Saturn V (or Falcon Heavy or Nova or BFR).

...Are you sure about that? Looking at the N1 launch explosions, I'd expect the VAB to be in significant danger if the Saturn V ever exploded. The explosion on the second N1 launch delayed the Soviet lunar program by 18 months.
Yes. Air blast and dramatic thermal effect radius does not extend multiple miles. It extends for about a mile, worst-case (i.e. if you were able to release ALL the energy instantaneously like a bomb, which is a highly unrealistic and pessimistic assumption). Of course, a rocket could also veer off-course, but that's what FTS is for.

...things like broken windows due to the blast are possible over a much wider radius.
Title: Re: Where will BFR launch from?
Post by: The Amazing Catstronaut on 06/19/2016 09:13 pm


...things like broken windows due to the blast are possible over a much wider radius.

And occurred, during normative Saturn V launches.
Title: Re: Where will BFR launch from?
Post by: Nomadd on 06/19/2016 10:19 pm
 This thread is interesting when you can see the Boca Chica launch site from your living room window while reading it.
 So, do I need a hardhat or not?
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/19/2016 11:52 pm
This thread is interesting when you can see the Boca Chica launch site from your living room window while reading it.
 So, do I need a hardhat or not?
I'd invest in one... As well as shatter-proof windows!
Title: Re: Where will BFR launch from?
Post by: docmordrid on 06/20/2016 03:31 am
This thread is interesting when you can see the Boca Chica launch site from your living room window while reading it.
 So, do I need a hardhat or not?
I'd invest in one... As well as shatter-proof windows!

Aluminium oxynitride ceramic windows  ("transparent aluminum") can stop a .50 BMG ;)
Title: Re: Where will BFR launch from?
Post by: sghill on 06/20/2016 03:39 am
This thread is interesting when you can see the Boca Chica launch site from your living room window while reading it.
 So, do I need a hardhat or not?
I'd invest in one... As well as shatter-proof windows!

...which summarizes why it won't happen there.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/20/2016 03:40 am
This thread is interesting when you can see the Boca Chica launch site from your living room window while reading it.
 So, do I need a hardhat or not?
I'd invest in one... As well as shatter-proof windows!

...which summarizes why it won't happen there.
You thought I was talking about BFR, not Falcon Heavy?
Title: Re: Where will BFR launch from?
Post by: sghill on 06/20/2016 03:41 am
This thread is interesting when you can see the Boca Chica launch site from your living room window while reading it.
 So, do I need a hardhat or not?
I'd invest in one... As well as shatter-proof windows!

...which summarizes why it won't happen there.
You thought I was talking about BFR, not Falcon Heavy?

Yep.

Silly me. Thinking we were on topic.  :)
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/20/2016 03:47 am
This thread is interesting when you can see the Boca Chica launch site from your living room window while reading it.
 So, do I need a hardhat or not?
I'd invest in one... As well as shatter-proof windows!

...which summarizes why it won't happen there.
You thought I was talking about BFR, not Falcon Heavy?

Yep.

Silly me. Thinking we were on topic.  :)
Falcon Heavy and BFR are within half an order of magnitude of each other. And within a factor of 50% for blast radius. You're not much safer with FH than you are with BFR.

Which is my point. People think that FH and BFR are so far apart that you have to think about them differently. No, they're remarkably close to the same blast radius (since power is dissipated over volume or surface area, i.e. cubed or squared, not linear).

My comments apply to both FH and BFR. Buy those shatterproof windows.
Title: Re: Where will BFR launch from?
Post by: Nomadd on 06/20/2016 04:26 am
If they break, SpaceX will pay for shatterproof windows. No reason for me to put out. I'll be out in the yard watching or in a refugee camp or something if they evacuate for launch.
Title: Re: Where will BFR launch from?
Post by: dorkmo on 06/20/2016 05:33 am
Ah, but an offshore launch platform could be made mostly of steel.  Not huge amounts of concrete in an offshore drilling rig, which is the closest analog to an offshore BFR launch platform...

True, but it would still be one heck of a structure for supporting the weight of a fully fueled BFR, and some shipyard somewhere is going to get the contract to build it.  Again, not something that could be hidden.

if they were to go offshore, id guess a south korean shipbuilder would get the contract.
Title: Re: Where will BFR launch from?
Post by: philw1776 on 06/20/2016 01:21 pm
This thread is interesting when you can see the Boca Chica launch site from your living room window while reading it.
 So, do I need a hardhat or not?

Look on Ebay for used SkyLab Helmets, cheap!

I'm cautious and always wear a football helmet outside when observing meteor showers.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/20/2016 01:37 pm
This thread is interesting when you can see the Boca Chica launch site from your living room window while reading it.
 So, do I need a hardhat or not?

You're about 2 miles from the pad, right? You're probably safe indoors as long as you don't get too close to that window. Flying glass from shattered windows is nasty. For lawn viewing, I'd consider a hardhat. Flying debris can definitely travel that far from a large explosion, although the probability of getting hit would be really, really low.
Title: Re: Where will BFR launch from?
Post by: CNYMike on 06/20/2016 01:57 pm
SpaceX has a different opinion than NASA on whether it's better to build really expensive and hardened facilities or super cheap and easily replaced facilities. Based on that, I say that, logically, SpaceX will NOT be building a VAB or anything like it. They will be building something cheap and easily replaced. Something like the HIF but about twice as much volume (+/-50%).

Even then, where is it?  Who's getting the contract?  He's given himself a deadline only 8 years away; there are only 3 launch windows before 2024.  There's a lot to do and a short time to do it in, and there's no way in this day and age someone wouldn't sneak a photo and put it online.  So where is it?  There should be something concrete out there and no room for theorizing by now.
Title: Re: Where will BFR launch from?
Post by: sghill on 06/20/2016 04:24 pm
SpaceX has a different opinion than NASA on whether it's better to build really expensive and hardened facilities or super cheap and easily replaced facilities. Based on that, I say that, logically, SpaceX will NOT be building a VAB or anything like it. They will be building something cheap and easily replaced. Something like the HIF but about twice as much volume (+/-50%).

Even then, where is it?  Who's getting the contract?  He's given himself a deadline only 8 years away; there are only 3 launch windows before 2024.  There's a lot to do and a short time to do it in, and there's no way in this day and age someone wouldn't sneak a photo and put it online.  So where is it?  There should be something concrete out there and no room for theorizing by now.

Just because it isn't in the public eye doesn't mean the work is vaporware. See also, Blue Origin.

This fall's reveal may free up suppliers to discuss their contracts.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/20/2016 05:24 pm
SpaceX has a different opinion than NASA on whether it's better to build really expensive and hardened facilities or super cheap and easily replaced facilities. Based on that, I say that, logically, SpaceX will NOT be building a VAB or anything like it. They will be building something cheap and easily replaced. Something like the HIF but about twice as much volume (+/-50%).

Even then, where is it?  Who's getting the contract?  He's given himself a deadline only 8 years away; there are only 3 launch windows before 2024.  There's a lot to do and a short time to do it in, and there's no way in this day and age someone wouldn't sneak a photo and put it online.  So where is it?  There should be something concrete out there and no room for theorizing by now.

Echoing what sghill said, just because we haven't heard about it doesn't mean it's not happening. How soon before the HIF was built did we know who was building it? You may have to just wait until September. It's only 3 months away.

How long did it take to build the HIF?

From the pouring of the slab to the actual completion of the exterior was about 10 months. Let's say 15 months for a building 2-3x as big. First MCT to Mars is in 2022 /at earliest/, right? So, in principle, they wouldn't need until 2021 before they start on it, if a suitable spot has been found.

And yes, that's without margin... but the 2022 date is without much margin, too. I'm being consistent.


(BTW, the VAB itself, of much sturdier construction and much larger than the BFR's HIF will be, was built in just 3 years.)
Title: Re: Where will BFR launch from?
Post by: Ionmars on 06/21/2016 01:58 pm
...
Even then, where is it?  Who's getting the contract?  He's given himself a deadline only 8 years away; there are only 3 launch windows before 2024.  There's a lot to do and a short time to do it in, and there's no way in this day and age someone wouldn't sneak a photo and put it online.  So where is it?  There should be something concrete out there and no room for theorizing by now.
Shotwell has said on occasion that Falcon heavy will play a big role in the early phase of Mars architecture before BFR is fully developed. Other persons have speculated that MCT would haver to br ready by 2022. I expect that FH will be the way that a few humans could land on Mars by 2025. In that case the launch facilities for the first Mars rocket are already constructed.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/21/2016 02:12 pm
...
Even then, where is it?  Who's getting the contract?  He's given himself a deadline only 8 years away; there are only 3 launch windows before 2024.  There's a lot to do and a short time to do it in, and there's no way in this day and age someone wouldn't sneak a photo and put it online.  So where is it?  There should be something concrete out there and no room for theorizing by now.
Shotwell has said on occasion that Falcon heavy will play a big role in the early phase of Mars architecture before BFR is fully developed. Other persons have speculated that MCT would haver to br ready by 2022. I expect that FH will be the way that a few humans could land on Mars by 2025. In that case the launch facilities for the first Mars rocket are already constructed.
A perfectly valid understanding of that statement by Shotwell is that she was referring to Red Dragon.

Additionally, BFS will need near-SSTO performance already, so it's possible it could launch /itself/ from the Earth's surface to orbit and be fitted out (consumables, propellant, crew) by Falcon Heavy & F9 in orbit. BFS would necessarily have less thrust than Falcon Heavy if we believe 15mlbf for BFR.
Title: Re: Where will BFR launch from?
Post by: JamesH65 on 06/21/2016 02:17 pm
SpaceX has a different opinion than NASA on whether it's better to build really expensive and hardened facilities or super cheap and easily replaced facilities. Based on that, I say that, logically, SpaceX will NOT be building a VAB or anything like it. They will be building something cheap and easily replaced. Something like the HIF but about twice as much volume (+/-50%).

Even then, where is it?  Who's getting the contract?  He's given himself a deadline only 8 years away; there are only 3 launch windows before 2024.  There's a lot to do and a short time to do it in, and there's no way in this day and age someone wouldn't sneak a photo and put it online.  So where is it?  There should be something concrete out there and no room for theorizing by now.

The Shard in London took 3 years 8 months to build, much more complicated than anything proposed here. The Olympics cities have 7 years or so to build the Olympic infrastructure. Again, hugely more complicated. In 8 years you can build almost anything you like.

Except my local village hall. That took over 10 years from "we need a new village hall" to finish.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/21/2016 03:03 pm
...
Even then, where is it?  Who's getting the contract?  He's given himself a deadline only 8 years away; there are only 3 launch windows before 2024.  There's a lot to do and a short time to do it in, and there's no way in this day and age someone wouldn't sneak a photo and put it online.  So where is it?  There should be something concrete out there and no room for theorizing by now.
Shotwell has said on occasion that Falcon heavy will play a big role in the early phase of Mars architecture before BFR is fully developed. Other persons have speculated that MCT would haver to br ready by 2022. I expect that FH will be the way that a few humans could land on Mars by 2025. In that case the launch facilities for the first Mars rocket are already constructed.
A perfectly valid understanding of that statement by Shotwell is that she was referring to Red Dragon.

Additionally, BFS will need near-SSTO performance already, so it's possible it could launch /itself/ from the Earth's surface to orbit and be fitted out (consumables, propellant, crew) by Falcon Heavy & F9 in orbit. BFS would necessarily have less thrust than Falcon Heavy if we believe 15mlbf for BFR.

BFS will likely have about 1/2 the thrust of FH, but SSTO? I doubt it. Vac engines get awful efficiency and thrust at sea level, even with a retracted nozzle extension. Like SuperDraco awful isp. That's fine for a few hundred m/s to land an empty ship on Earth, but taking off with a mostly-full prop load is a whole different proposition.

Lets say the Raptor vacuum engine has a retractable nozzle with 165:1 vac expansion and 65:1 retracted expansion (33% length), with a 0.11 m^2 throat and 10 MPa chamber pressure. That gets you 379s isp and 2250 kN thrust in vacuum. Now retract the nozzle and launch at SL: 236 isp and 1400 kN thrust. Terrible.

With a 40t dry weight and 840t of propellent, and a 308 average isp, it gets 9200 m/s dV which works. But achieving liftoff requires 8 Rvacs or 5 SL-optimized 2300 kN Raptors. That may be possible, but it's a very different beast than a BFS optimized to operate almost entirely in vacuum and Mars/zero gravity.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/21/2016 03:11 pm
...Now retract the nozzle and launch at SL: 236 isp and 1400 kN thrust. Terrible.

Come on, that's absurd.

Raptor can get 321s sea level Isp according to Mueller, and at least one of the engines has to work at sea level anyway for landing (and quite likely would be used in vacuum as well, probably with an extension), so they're not going to design a piece of crap like you just described.


Your overall point that BFS would need more thrust for SSTO than it would as mere BFS is a heck of a lot better if you don't use totally misleading figures.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/21/2016 03:30 pm
...Now retract the nozzle and launch at SL: 236 isp and 1400 kN thrust. Terrible.

Come on, that's absurd.

Raptor can get 320s sea level Isp, and at least one of the engines has to work at sea level anyway for landing (and quite likely would be used in vacuum as well, probably with an extension), so they're not going to design a piece of crap like you just described.


Your overall point that BFS would need more thrust for SSTO than it would as mere BFS is a heck of a lot better if you don't use totally misleading figures.

Not absurd, it's just reality. Plug my estimated engine parameters into a design simulator and you will get the same answer. It's not a question of poor design, it's the physics of optimal nozzle expansion. You can't just slap an vac nozzle on a SL engine and call it a vac engine. Vacuum engines reach SL expansion very rapidly with a lot of radial flow after the throat, leading to really poor efficiency (and really bad flow separation) at SL.

I never said they wouldn't work at SL for landing. You don't need an optimized nozzle for landing. You DO need a highly optimized nozzle(s) to achieve 380 isp in vacuum, and vacuum is 99% of the operating regime for BFS. If you compromise on vacuum operation to get better SL performance (like the SSMEs), you will never get 380s out of methalox.

And you still would need 6 Raptors at minimum, which is considerable overkill for all other BFS requirements.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/21/2016 03:31 pm
...Now retract the nozzle and launch at SL: 236 isp and 1400 kN thrust. Terrible.

Come on, that's absurd.

Raptor can get 320s sea level Isp, and at least one of the engines has to work at sea level anyway for landing (and quite likely would be used in vacuum as well, probably with an extension), so they're not going to design a piece of crap like you just described.


Your overall point that BFS would need more thrust for SSTO than it would as mere BFS is a heck of a lot better if you don't use totally misleading figures.

Not absurd, it's just reality. Plug my estimated engine parameters into a design simulator and you will get the same answer. It's not a question of poor design, it's the physics of optimal nozzle expansion. You can't just slap an vac nozzle on a SL engine and call it a vac engine...
...actually you can it'll just be longer. Yes, the reverse is not true.

If SpaceX does use BFS as a SSTO, they will do a better job of making it work than a naive design you suggested.

I'm merely covering all options.

Personally, I think BFS-as-SSTO is not likely. More likely is Musk just building the BFR earlier than most people expect, and that Shotwell's comments were referring to landing equipment with Red Dragon and Falcon Heavy.


...but there is one possible advantage of the BFS-as-SSTO beyond the very early days: fewer staging events. If it was super lightly loaded with JUST people and very basic ECLSS (cargo loaded on orbit), it /might/ be safer than launching on top of BFR. (Though the lower margin for reaching orbit would counter-act some of the safety.)
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/21/2016 03:40 pm
So you can take a SL engine, put a longer bell on it, and have a vacuum engine? Why then can't you that that same engine, (which is now a good vac engine) take the bell off, and get your original SL engine back? Where is this non-linear?

Extension geometry for conical nozzles is a lot simpler, and you can change nozzle length and expect linear effects. Bell nozzles don't work that way, and you can't do this and expect optimal nozzles.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/21/2016 03:43 pm
So you can take a SL engine, put a longer bell on it, and have a vacuum engine? Why then can't you that that same engine, (which is now a good vac engine) take the bell off, and get your original SL engine back? Where is this non-linear?
...
If you design an engine for vacuum, you also want to minimize its length (to minimize mass, including the mass of the interstage). That determines the optimal angle to use, not just the exit conditions alone.

Additionally, there are other options beyond a simple bell nozzle. A dual-bell also is possible.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/21/2016 04:29 pm
Actually, retractable nozzles usually have an expansion ratio of ~50:1, but an extendable nozzle with the retraction split pulled back to about 15% of the nozzle length gets the retracted expansion ratio down to ~20:1 so the SL ISP goes up to ~300s and the thrust to ~2000 kN if they run the chamber at 12MPa. That ISP increase is enough to reduce fuel requirements to ~650t so that a very lightweight (~42t) 4-engine vehicle could put itself in a low parking orbit for refueling.

I don't think anyone has flown a engine like that, and it has it own set of engineering difficulties. But that certainly doesn't mean SpaceX wouldn't try.

Edit: it would also improve landing margins by at least 20% over a RL10-B style extendable design, so they might find the design trades worthwhile, even if they don't try to use it as a SSTO.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/21/2016 04:31 pm
Actually, retractable nozzles usually have an expansion ratio of ~50:1, but an extendable nozzle with the retraction split pulled back to about 15% of the nozzle length gets the retracted expansion ratio down to ~20:1 so the SL ISP goes up to ~300s and the thrust to ~2000 kN if they run the chamber at 12MPa. That ISP increase is enough to reduce fuel requirements to ~650t so that a very lightweight (~42t) 4-engine vehicle could put itself in a low parking orbit for refueling.

I don't think anyone has flown a engine like that, and it has it own set of engineering difficulties. But that certainly doesn't mean SpaceX wouldn't try.
They may want an engine like that for the center landing engine in any case.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/21/2016 04:38 pm
Actually, retractable nozzles usually have an expansion ratio of ~50:1, but an extendable nozzle with the retraction split pulled back to about 15% of the nozzle length gets the retracted expansion ratio down to ~20:1 so the SL ISP goes up to ~300s and the thrust to ~2000 kN if they run the chamber at 12MPa. That ISP increase is enough to reduce fuel requirements to ~650t so that a very lightweight (~42t) 4-engine vehicle could put itself in a low parking orbit for refueling.

I don't think anyone has flown a engine like that, and it has it own set of engineering difficulties. But that certainly doesn't mean SpaceX wouldn't try.
They may want an engine like that for the center landing engine in any case.

Yes, see my edit. None of this has a whole lot to do with BFR launches though - I think BFR will first launch from Boca Chica, and it will launch at a considerably higher thrust than FH.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/21/2016 05:08 pm
Actually, retractable nozzles usually have an expansion ratio of ~50:1, but an extendable nozzle with the retraction split pulled back to about 15% of the nozzle length gets the retracted expansion ratio down to ~20:1 so the SL ISP goes up to ~300s and the thrust to ~2000 kN if they run the chamber at 12MPa. That ISP increase is enough to reduce fuel requirements to ~650t so that a very lightweight (~42t) 4-engine vehicle could put itself in a low parking orbit for refueling.

I don't think anyone has flown a engine like that, and it has it own set of engineering difficulties. But that certainly doesn't mean SpaceX wouldn't try.
They may want an engine like that for the center landing engine in any case.

Yes, see my edit. None of this has a whole lot to do with BFR launches though - I think BFR will first launch from Boca Chica, and it will launch at a considerably higher thrust than FH.
I agree. Of all the places BFR may launch first from, Boca Chica seems most likely. And thrust of 15mlbf according to Musk. 3-4 times Falcon Heavy's thrust according to Shotwell.
Title: Re: Where will BFR launch from?
Post by: Lars-J on 06/21/2016 06:11 pm
I can't wait to see a BFR stage moved to the pad...

Here are some recent pictures of an S-1C stage being moved for reference, a BFR 1st stage will likely be larger. :)
Title: Re: Where will BFR launch from?
Post by: JasonAW3 on 06/21/2016 06:25 pm
Let's be honest.

     The BFS will likely use as few engines as possible, to simplify the design and fuel flows, while providing enough redundancy to be able to complete the mission, or failing that, a safe abort to another landing site.

     I would not be surprised if the BFS has some of its' engines dedicated as vacuum engines, but still somewhat usable at sea level.

     As to launching from Boca Chica, I have serious doubts about this as there are residential structures that appear to be well within the possible blast radius of the BFS, should something go catastrophically wrong on launch.  Noise issues are a whole different animal and potentially COULD be at least partially mitigated, through use of some clever technology.

     Possibly the use of counter noise generation with speakers out of the main launch zone, and a delay sufficient to match up with the noise wave from the rocket.  This won't eliminate the noise entirely, but it will dampen it until at a higher altitude, significantly.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/21/2016 06:33 pm
Let's be honest.
...
You implying we're not being honest?

Quote
As to launching from Boca Chica, I have serious doubts about this as there are residential structures that appear to be well within the possible blast radius of the BFS, should something go catastrophically wrong on launch.  Noise issues are a whole different animal and potentially COULD be at least partially mitigated, through use of some clever technology....
"Let's be honest." BFS to first order would have the same exact blast radius as Falcon Heavy as well as the same noise levels. With the benefit of much less sooty exhaust, fewer engines, and fewer stages.


Yet again, people are under-estimating Falcon Heavy. It's an enormous rocket.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/21/2016 06:46 pm
The main difference between BFR and FH catastrophically exploding is that methane has more energy and can release it faster than kerosene. The effective blast radius for BFR will likely be 50% to 80% greater than FH.

That said, the actual blast effects from a catastrophic explosion are unlikely to be dangerous beyond a mile or two. Broken windows are likely going to happen in Boca Chica village even during a normal FH launch, but other than that actual damage should be very limited even in a worst-case event.

For reference, both the 1 psi pressure wave and the 0% probability burn limit for a 2kt TNT explosion are about 1 mile. The nearest buildings are ~1.8 miles from the pad, definitely outside the range for anything other than a mild over-pressure and some flying debris.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/21/2016 06:53 pm
The main difference between BFR and FH catastrophically exploding is that methane has more energy and can release it faster than kerosene. The effective blast radius for BFR will likely be 50% to 80% greater than FH.
...
Yes, for BFR. But JasonAW3 was talking about BFS.

...but remember also the different mixture ratios. There's more fuel per unit lift-off mass for a kerosene rocket than for a methane rocket. That largely cancels out the difference in energy.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/21/2016 07:29 pm
The main difference between BFR and FH catastrophically exploding is that methane has more energy and can release it faster than kerosene. The effective blast radius for BFR will likely be 50% to 80% greater than FH.
...
Yes, for BFR. But JasonAW3 was talking about BFS.

...but remember also the different mixture ratios. There's more fuel per unit lift-off mass for a kerosene rocket than for a methane rocket. That largely cancels out the difference in energy.

True. BFS should be about 1/2 thrust and noise, and somewhat lower in total energy than Falcon Heavy. I still have doubts that it will ever lift off from Earth though (at least without a BFR underneath).

The Saturn V second stage was estimated at the time to have more potential energy than the first stage, despite having far less mass of hydrogen (and LOX) than the first stage. Methane is closer to RP1 than it is to LH2, but BFR will have much more fuel mass than FH, and methane is a lot more volatile than RP-1. I'll ballpark 5 to 8 times as much total released energy in a catastrophic explosion.

"In September 1963, NASA conducted a short study of Saturn 5 booster explosion hazards and how they affected the survivability of the Apollo spacecraft. Titled “Saturn 5 Booster Explosion Hazards and Apollo Survivability Analyses,” the study focused on an on-pad explosion, and its authors calculated the propellant weights in each of the three stages and determined their equivalent weight in terms of TNT, a common means of establishing a benchmark for explosive yields. The study’s authors concluded that there was the equivalent of 222,000 kilograms of TNT in the S-IC first stage, 253,000 kilograms of TNT in the S-II second stage, and 68,000 kilograms of TNT in the S-IVB third stage. Although the propellant weight of the first stage was considerably higher than the second stage, the second stage’s explosive yield was greater because it utilized more explosive liquid hydrogen and liquid oxygen."

http://www.thespacereview.com/article/591/1
Title: Re: Where will BFR launch from?
Post by: joek on 06/21/2016 09:09 pm
The main difference between BFR and FH catastrophically exploding is that methane has more energy and can release it faster than kerosene. The effective blast radius for BFR will likely be 50% to 80% greater than FH.

That said, the actual blast effects from a catastrophic explosion are unlikely to be dangerous beyond a mile or two. Broken windows are likely going to happen in Boca Chica village even during a normal FH launch, but other than that actual damage should be very limited even in a worst-case event.

For reference, both the 1 psi pressure wave and the 0% probability burn limit for a 2kt TNT explosion are about 1 mile. The nearest buildings are ~1.8 miles from the pad, definitely outside the range for anything other than a mild over-pressure and some flying debris.

There are several safety rules and analyses required by the FAA.  One of the simplest and accesible is the near-launch-point blast hazard area, which defines the 1 psi overpressure boundary.[1]  From FAA CFR §417 (http://www.ecfr.gov/cgi-bin/text-idx?SID=cf05cbda1980d078aeed5c640f24ff6a&mc=true&node=sp14.4.417.e&rgn=div6)...
Quote
§A417.23   Flight hazard areas
...

(d) Near-launch-point blast hazard area. A flight hazard area analysis must define a blast overpressure hazard area as a circle extending from the launch point with a radius equal to the 1.0 psi overpressure distance produced by the equivalent TNT weight of the explosive capability of the vehicle. In addition, the analysis must establish a minimum near-pad blast hazard area to provide protection from hazardous fragments potentially propelled by an explosion. The analysis must account for the maximum possible total solid and liquid propellant explosive potential of the launch vehicle and any payload. The analysis must define a blast overpressure hazard area using the following equations:

Rop = 45 · (NEW)1/3
Where:
Rop is the over pressure distance in feet.
NEW = WE · C (pounds).
WE is the weight of the explosive in pounds.
C is the TNT equivalency coefficient of the propellant being evaluated. A launch operator must identify the TNT equivalency of each propellant on its launch vehicle including any payload. TNT equivalency data for common liquid propellants is provided in tables A417-1. Table A417-2 provides factors for converting gallons of specified liquid propellants to pounds.

...

Table A417-1
LO2/RP–1: 20% of W up to 500,000 pounds plus 10% of W over 500,000 pounds, where W is the weight of LO2RP–1
LO2/LH2: The larger of: 8W2/3 where W is the weight of LO2/LH2, or 14% of W.

Unfortunately they don't give a value or formula for LO2/LCH4 TNT equivalence.  Example results (approximate, excluding payload): F9, 2500'; FH 3200'.


[1] The others analyses require information about the vehicle, payload and analysis for which public information is not available.
Title: Re: Where will BFR launch from?
Post by: launchwatcher on 06/21/2016 09:16 pm
The Shard in London took 3 years 8 months to build, much more complicated than anything proposed here. The Olympics cities have 7 years or so to build the Olympic infrastructure. Again, hugely more complicated. In 8 years you can build almost anything you like.

Except my local village hall. That took over 10 years from "we need a new village hall" to finish.
Not surprising at all.   Classic bikeshedding (https://en.wikipedia.org/wiki/Law_of_triviality).

Consider the wide-open planning process attempting to nailing down the requirements for a multi-purpose public building -- offices, small meeting spaces, large meeting spaces, something that expresses the spirit of the town, where every village resident should have a say in the aesthetics of the place.   Managing the discussion is like herding cats.

Much easier to keep a launch pad project on track, especially if you've already rebuilt a few smaller ones..

Title: Re: Where will BFR launch from?
Post by: docmordrid on 06/21/2016 11:58 pm
WRT yields: NASA have SV a total yield of 543,000 kg tnt or 0.543 kt.

Even without a CH4 v tnt chart can we assume modelling almost an order of magnitude greater yield would cover things? The below model is a 5 kt nuclear airburst.

5 psi (structural damage): 1.19 km
1.5 psi (broken windows): 2.73 km
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/22/2016 12:13 am
The main difference between BFR and FH catastrophically exploding is that methane has more energy and can release it faster than kerosene. The effective blast radius for BFR will likely be 50% to 80% greater than FH.

That said, the actual blast effects from a catastrophic explosion are unlikely to be dangerous beyond a mile or two. Broken windows are likely going to happen in Boca Chica village even during a normal FH launch, but other than that actual damage should be very limited even in a worst-case event.

For reference, both the 1 psi pressure wave and the 0% probability burn limit for a 2kt TNT explosion are about 1 mile. The nearest buildings are ~1.8 miles from the pad, definitely outside the range for anything other than a mild over-pressure and some flying debris.

There are several safety rules and analyses required by the FAA.  One of the simplest and accesible is the near-launch-point blast hazard area, which defines the 1 psi overpressure boundary.[1]  From FAA CFR §417 (http://www.ecfr.gov/cgi-bin/text-idx?SID=cf05cbda1980d078aeed5c640f24ff6a&mc=true&node=sp14.4.417.e&rgn=div6)...
Quote
§A417.23   Flight hazard areas
...

(d) Near-launch-point blast hazard area. A flight hazard area analysis must define a blast overpressure hazard area as a circle extending from the launch point with a radius equal to the 1.0 psi overpressure distance produced by the equivalent TNT weight of the explosive capability of the vehicle. In addition, the analysis must establish a minimum near-pad blast hazard area to provide protection from hazardous fragments potentially propelled by an explosion. The analysis must account for the maximum possible total solid and liquid propellant explosive potential of the launch vehicle and any payload. The analysis must define a blast overpressure hazard area using the following equations:

Rop = 45 · (NEW)1/3
Where:
Rop is the over pressure distance in feet.
NEW = WE · C (pounds).
WE is the weight of the explosive in pounds.
C is the TNT equivalency coefficient of the propellant being evaluated. A launch operator must identify the TNT equivalency of each propellant on its launch vehicle including any payload. TNT equivalency data for common liquid propellants is provided in tables A417-1. Table A417-2 provides factors for converting gallons of specified liquid propellants to pounds.

...

Table A417-1
LO2/RP–1: 20% of W up to 500,000 pounds plus 10% of W over 500,000 pounds, where W is the weight of LO2RP–1
LO2/LH2: The larger of: 8W2/3 where W is the weight of LO2/LH2, or 14% of W.

Unfortunately they don't give a value or formula for LO2/LCH4 TNT equivalence.  Example results (approximate, excluding payload): F9, 2500'; FH 3200'.


[1] The others analyses require information about the vehicle, payload and analysis for which public information is not available.
What IS public is the thrust of 15mlbf. Assume the T/W=~1.25 and that 90% of the mass of the rocket is propellant. That should get you quite close to the actual result, within ~10%.


...so I'll assume: 15E6lb*.8*.9*1kg/(2.2lb).
That gives 4900tons of propellant.

If we use kerolox's 10%, that's 0.49kT. If we use the lower figure for hydrogen (which is probably a good compromise), then 0.686kT or about 1,500,000 lb of TNT equiv.

So, using the larger figure, that's:
45ft*(1500000)^(1/3) = 5150ft. Essentially, 1 mile on the nose (to within the precision we were given). Compared to about 1km for Falcon Heavy.


That power to the third is why launching BFR from Boca Chica isn't so ridiculous, provided Falcon Heavy is reasonable.
Title: Re: Where will BFR launch from?
Post by: joek on 06/22/2016 12:45 am
What IS public is the thrust of 15mlbf. Assume the T/W=~1.25 and that 90% of the mass of the rocket is propellant. That should get you quite close to the actual result, within ~10%.

...so I'll assume: 15E6lb*.8*.9*1kg/(2.2lb)...

The non-public information I was referring to relates to debris impact line limits, distance-focused overpressure, etc., which tend to enlarge the area. (E.g., FAA waiver required for CCAFS RTLS due to debris impact line limit violation.)  Public information sufficient to perform a credible independent analysis is not available.

In any case, your numbers are similar to my BOTE and likely good enough for discussion.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/22/2016 01:04 am
Well, the nice thing about BFR is the lack of any solid rocket motors. So you don't get this: https://www.youtube.com/watch?v=z_aHEit-SqA

With a failure, you'd get a BIG fireball, but no long-lived flamey fire-and-brimstone effect.
Title: Re: Where will BFR launch from?
Post by: cartman on 06/22/2016 04:30 pm
I can't wait to see a BFR stage moved to the pad...

Here are some recent pictures of an S-1C stage being moved for reference, a BFR 1st stage will likely be larger. :)
For reference, a Falcon 9 is about the same diameter (3.7m) as each F-1 engine on the Saturn V!
Title: Re: Where will BFR launch from?
Post by: guckyfan on 06/24/2016 01:27 pm
We have heard that NASA wants to lease out land in the LC-39 area. Is it possible that there are building permits for a Nova-class rocket pad still valid for that area and that SpaceX could build their BFR-pad there with less EPA EIS hassle?

Title: Re: Where will BFR launch from?
Post by: BobHk on 06/24/2016 07:21 pm
I can't wait to see a BFR stage moved to the pad...

Here are some recent pictures of an S-1C stage being moved for reference, a BFR 1st stage will likely be larger. :)
For reference, a Falcon 9 is about the same diameter (3.7m) as each F-1 engine on the Saturn V!

Shotwell indicated it'll have to be built on the pad Lars, i'm still trying to find that video of her saying that again.  We might never get to see one roll out, just grow 'up' on the pad.

Makes my thoughts of building a BFR on the pad out of 9 raptor bottomed strapped together F9 first stages seem more realistic (to me! /ducks)...at least you'd only have to assemble it on the pad to launch.  They could still build all the major parts at Hawthorne and truck them over. 

I visited the JSC this last weekend with my family and got to see the Saturn V there again (my twentieth time since the late seventies when it was still out in the open air) and couldn't help thinking how awesome it would be for our generation to surpass it...finally, and get some work done out there beyond the moons (now that its official Earth has two since about 50 years ago). 
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/24/2016 07:35 pm
We have heard that NASA wants to lease out land in the LC-39 area. Is it possible that there are building permits for a Nova-class rocket pad still valid for that area and that SpaceX could build their BFR-pad there with less EPA EIS hassle?
I bet that's something KSC and Space Florida are probably lobbying SpaceX for.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/24/2016 08:29 pm
Shotwell said it would be built at the launch site (referring to the manufacturing location being near the pad). I don't remember ever hearing that it would be stacked on the launch pad. I think it will be assembled horizontally and rolled out.
Title: Re: Where will BFR launch from?
Post by: BobHk on 06/24/2016 08:45 pm
Shotwell said it would be built at the launch site (referring to the manufacturing location being near the pad). I don't remember ever hearing that it would be stacked on the launch pad. I think it will be assembled horizontally and rolled out.

I guess we'll find out soon enough.  Cheaper solution seems to build a capable pad to construct it on and launch it from there, no rolling or overbuilt roadways or canals needed.  Soon...
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/24/2016 08:59 pm
Each shuttle SRB massed about twice what the whole BFR stack will mass when dry, even with payload. It's going to be huge, but not heavy until it's fueled on the pad.
Title: Re: Where will BFR launch from?
Post by: BobHk on 06/24/2016 09:24 pm
Each shuttle SRB massed about twice what the whole BFR stack will mass when dry, even with payload. It's going to be huge, but not heavy until it's fueled on the pad.

Define not heavy then tell me how thick the road has to be.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/24/2016 09:38 pm
Each shuttle SRB massed about twice what the whole BFR stack will mass when dry, even with payload. It's going to be huge, but not heavy until it's fueled on the pad.

Define not heavy then tell me how thick the road has to be.
BFR likely will be incredibly lightweight empty given its size. It'll probably be transported on one of those multi-wheeled dealies they use for Falcon 9. Those things can handle about an order of magnitude more weight than BFR will be empty.

To first order, about 300 tons but quite long. Spread over a couple dozen axles or so. Road doesn't even necessarily need to be reinforced beyond typical highway standards.
Title: Re: Where will BFR launch from?
Post by: whitelancer64 on 06/24/2016 09:52 pm
Each shuttle SRB massed about twice what the whole BFR stack will mass when dry, even with payload. It's going to be huge, but not heavy until it's fueled on the pad.

Define not heavy then tell me how thick the road has to be.

A Shuttle SRB weighed 1.3 million pounds. If the BFR is half that (when unfueled) that means it would be 650,000 pounds. Distributed over some 300 feet, that's roughly a ton per foot in length.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/24/2016 10:14 pm
Each shuttle SRB massed about twice what the whole BFR stack will mass when dry, even with payload. It's going to be huge, but not heavy until it's fueled on the pad.

Define not heavy then tell me how thick the road has to be.

A Shuttle SRB weighed 1.3 million pounds. If the BFR is half that (when unfueled) that means it would be 650,000 pounds. Distributed over some 300 feet, that's roughly a ton per foot in length.

Exactly. Or to put it another way, about the same weight per length as that Saturn V booster in the picture right up the thread getting towed down a road.

3 heavy axle railcars on standard track could also take the weight of the full stack. N1 was rolled out horizontally on railcars and erected on the pad.
Title: Re: Where will BFR launch from?
Post by: Bob Shaw on 06/24/2016 10:31 pm
You can indeed move *enormous* objects relatively simply - here's a big chunk of one of the new UK aircraft carriers, mounted on several 'trains' of remote controlled multi-wheel diesel modules. If memory serves, the block being moved here was about 4,000 tonnes in weight. This move was carried out by ALE, earlier ones were by Mammoet. Follow the same route on a regular basis and you won't need a worried-looking chap walking backwards in front of the BFR...
Title: Re: Where will BFR launch from?
Post by: guckyfan on 06/25/2016 01:36 pm
I guess we'll find out soon enough.  Cheaper solution seems to build a capable pad to construct it on and launch it from there, no rolling or overbuilt roadways or canals needed.  Soon...

They want it mass producable. The need to handle it to get it back on the launch pad after landing.
Title: Re: Where will BFR launch from?
Post by: GORDAP on 06/25/2016 03:54 pm
Each shuttle SRB massed about twice what the whole BFR stack will mass when dry, even with payload. It's going to be huge, but not heavy until it's fueled on the pad.

Define not heavy then tell me how thick the road has to be.

A Shuttle SRB weighed 1.3 million pounds. If the BFR is half that (when unfueled) that means it would be 650,000 pounds. Distributed over some 300 feet, that's roughly a ton per foot in length.

I'd think this comparison would be pretty irrelevant.   The shuttle SRB was in fact 'fully fueled' when in this state, and with a pretty dense fuel at that.  The BFR will weigh considerably less per unit area than an SRB.

The BFR will only be transported unfueled.  And it'll never use solids.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/25/2016 04:46 pm
Each shuttle SRB massed about twice what the whole BFR stack will mass when dry, even with payload. It's going to be huge, but not heavy until it's fueled on the pad.

Define not heavy then tell me how thick the road has to be.

A Shuttle SRB weighed 1.3 million pounds. If the BFR is half that (when unfueled) that means it would be 650,000 pounds. Distributed over some 300 feet, that's roughly a ton per foot in length.

I'd think this comparison would be pretty irrelevant.   The shuttle SRB was in fact 'fully fueled' when in this state, and with a pretty dense fuel at that.  The BFR will weigh considerably less per unit area than an SRB.

The BFR will only be transported unfueled.  And it'll never use solids.

Which is why the ground pressures under BFR/BFS during rollout (either separately or integrated) will be an order of magnitude lower than those under the Shuttle. Standard road or rail construction should be sufficient, and massive tracked vehicles and dedicated crawlerways unnecessary.
Title: Re: Where will BFR launch from?
Post by: BobHk on 06/25/2016 06:06 pm
And yet Shotwell hinted the BFR will have to be built on the pad...perhaps because they're making it without a mono tank?  Multiple road transportable tanks?  Are you all betting on massive tanks the full size of the diameter?
Title: Re: Where will BFR launch from?
Post by: docmordrid on 06/25/2016 06:38 pm
And yet Shotwell hinted the BFR will have to be built on the pad...perhaps because they're making it without a mono tank? 
>

Or - mono or not, she simply misspoke. 
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/25/2016 06:46 pm
And yet Shotwell hinted the BFR will have to be built on the pad......
...citation needed.

She said it would be built at (or near) the launch site.
Title: Re: Where will BFR launch from?
Post by: llanitedave on 06/25/2016 07:33 pm
Building on the pad really doesn't seem compatible with a fast launch cadence.
Title: Re: Where will BFR launch from?
Post by: cuddihy on 06/25/2016 08:33 pm
I wonder... Could BFR be so big that it wouldn't need an erector/ launcher by it?

I'm sure it'd still be processed horizontally--even if it's 20m wide, it's easier to reach a 20m height than a 50m height. And odds seem to be on 15-17m wide. But once erected, it's probably massive enough even empty to not need a TEL providing stability in wind. Only a service gantry/ arm would be needed, probably about the size of the current F9 TEL. In that case, there may be no need for a permanent vertical structure near the pad, so if the BFR was able to orient correctly, it could land back on the launch pad.
 I know, crazy right?
Title: Re: Where will BFR launch from?
Post by: Bob Shaw on 06/25/2016 08:52 pm
No. The bigger it gets, the more surface area to be blown about by the wind, and when empty it will be pretty light.
Title: Re: Where will BFR launch from?
Post by: cuddihy on 06/25/2016 08:58 pm
The current TEL isn't there to ensure the F9 stays in one place but to provide strenthening in the wind so that it doesn't see rediculous bending loads. But would a much squatter, thicker skinned stage (which it has to be anyway due to circumference), still need external support for bending loads?

As a data point, the F9 first stage is just fine without a TEL post-landing.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 06/26/2016 01:49 am
The current TEL isn't there to ensure the F9 stays in one place but to provide strenthening in the wind so that it doesn't see rediculous bending loads. But would a much squatter, thicker skinned stage (which it has to be anyway due to circumference), still need external support for bending loads?

As a data point, the F9 first stage is just fine without a TEL post-landing.

I know that the von Braun team (i.e. MSFC) in the early '60s decided to stack the Saturn V vertically and transport it vertically out to the pad in great measure to avoid bending loads.  Of course, with their solid Teutonic engineering, with everything overbuilt, I imagine there were more deltas between the mass of the thrust structures and that of the tanking, especially in the first stage.  I would think that would make bending loads worse.

Of course, it is always pointed out that the Soviets didn't seem to think bending loads an issue when they designed the N-1 to be built and transported to the pad horizontally and then erected once it reached the pad, just like the R-7 was.  Maybe they just had more familiarity with the bending loads on relatively larger, heavier structures, as deduced from R-7 behaviors, that led them to design their N-1 system that way.

(And yeah, the N-1 never flew successfully -- but I've never seen anything to even hint that any of the problems with it had anything to do with bending loads during construction or erection...)
Title: Re: Where will BFR launch from?
Post by: guckyfan on 06/26/2016 04:12 am
Just thinking of bending loads, when seeing a Falcon 9 first stage transported. Long and slender, very lightweight. They just put wheels under both ends and transport it over the highway.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/26/2016 04:27 am
Transport is easier than standing in terms of bending, because the supports are very far apart. On the pad, the supports are close together, and the moment arm twice as long.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 06/26/2016 04:37 am
Just thinking of bending loads, when seeing a Falcon 9 first stage transported. Long and slender, very lightweight. They just put wheels under both ends and transport it over the highway.

Well, to be honest, they connect the wheel trucks to handling rings (in the case of the road trucks, there are two sets of claw-like rings at each wheel truck, integral to the trucks), which are strategically connected to specially reinforced sections of the long, slender, lightweight stages, and I bet there are longitudinal stiffeners that run up and down the stages from those attach points.

In other words, it's not that simple rolled tubes of the aluminum-lithium alloy SpaceX uses for the Falcons are so strong they wouldn't show bending deformations without stiffeners.  Such stiffeners do add to the mass of the stage, but they also add strength and longitudinal stability, not just during transport and erection on the pad, but also in flight.  I'd be willing to bet that pretty much every airframe, for every type of aerospace vehicle, has such attach points connected to strengthened or reinforced sections of the airframe.

Besides, I seem to recall that SpaceX uses a chemically milled integral stiffening on the interiors of their vehicles, and tries to reclaim the material milled away from the etching chemicals.  Which means they can pattern the stiffeners and the attach points, both external and internal, into the metal using the milling process.  I believe the overall stiffening pattern is the grid pattern we can see in the internal views of the tanks.

I know that things like the Saturns had big metal stiffeners welded into their structures, though they became thinner and less massive the higher you got on the stack -- that staged rocket equation.  Maybe it was just an engineering intuition that was ultimately faulty, but back then, they worried about bending effects on rockets the size of the Saturn V, Nova -- and in this case, the BFR.  I figure that SpaceX thinks they have such things figured out, and aren't too worried about such effects with either FH or BFR, at this point.
Title: Re: Where will BFR launch from?
Post by: guckyfan on 06/26/2016 07:58 am
Just thinking of bending loads, when seeing a Falcon 9 first stage transported. Long and slender, very lightweight. They just put wheels under both ends and transport it over the highway.

Well, to be honest, they connect the wheel trucks to handling rings (in the case of the road trucks, there are two sets of claw-like rings at each wheel truck, integral to the trucks), which are strategically connected to specially reinforced sections of the long, slender, lightweight stages, and I bet there are longitudinal stiffeners that run up and down the stages from those attach points.

That does not change the fact that an ultralight cylinder takes all the bending load it experiences during road transport. There is no intermediate support.
Title: Re: Where will BFR launch from?
Post by: BobHk on 06/27/2016 04:25 am
And yet Shotwell hinted the BFR will have to be built on the pad......
...citation needed.

She said it would be built at (or near) the launch site.

https://www.youtube.com/watch?v=EoCDLUHb0y4&feature=youtu.be

3:40 to 4:05

How far from the pad do you think they'll build it when she says its not going to go over roads...
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/27/2016 04:34 am
And yet Shotwell hinted the BFR will have to be built on the pad......
...citation needed.

She said it would be built at (or near) the launch site.

https://www.youtube.com/watch?v=EoCDLUHb0y4&feature=youtu.be

3:40 to 4:05
So in other words, /exactly/ what I said.
"the Mars Colonial Transporter ...we're going to have to build that rocket at the launch site"

This is NOT the same thing as being built on the pad.
Title: Re: Where will BFR launch from?
Post by: BobHk on 06/27/2016 04:38 am
And yet Shotwell hinted the BFR will have to be built on the pad......
...citation needed.

She said it would be built at (or near) the launch site.

https://www.youtube.com/watch?v=EoCDLUHb0y4&feature=youtu.be

3:40 to 4:05
So in other words, /exactly/ what I said.
"the Mars Colonial Transporter ...we're going to have to build that rocket at the launch site"

This is NOT the same thing as being built on the pad.

and how far do you think shell build it from the pad if shes not intending to send it/parts of it over roadways?  a building a few miles from the pad might as well be the bloody pad.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/27/2016 04:45 am
No, it's significantly different operationally. Delta II was/is basically built on the pad. Building on the pad itself dramatically slows operations, obviously, since the pad can't be used for launching.
Title: Re: Where will BFR launch from?
Post by: docmordrid on 06/27/2016 05:08 am
>
and how far do you think shell build it from the pad if shes not intending to send it/parts of it over roadways?  a building a few miles from the pad might as well be the bloody pad.

Brownsville has a world class harbor and there's a shipping channel which can handle aircraft carries, and Musk testified before the TX legislature a factory for large cores could be part of this deal. They could build anywhere along that channel, which enters the Gulf 4.7 miles north of the pad.

The question is if they could  unload on an improved  Rte. 4 at the launch site using a shallow draft barge crane.
Title: Re: Where will BFR launch from?
Post by: darkenfast on 06/27/2016 09:18 am
While they might build pieces of the BFR in Brownsville, getting the rocket to the pad would be difficult.  The shipping channel is separated from the launch site by several miles of wetlands.  Dredging a channel and building a dock and roadway to the pad would have to get past an awful lot of environmental and political hurdles.  Then there's the other big issue: where are you going to test-fire this thing?  McGregor can't do it.  SpaceX has already said that they will make hearing protection available for Boca Chica residents during Falcon launches.  I seriously doubt that a full-duration test of a BFR is going to be allowed there.  The only water-accessible place that can test-fire something this big is Stennis.  The only place that can launch something this big is (at the moment), KSC (maybe).  Unless SpaceX surprises us with dancing unicorns, there simply aren't a lot of places with that kind of buffer zone, access and (in the case of launches) safe downrange areas.
Title: Re: Where will BFR launch from?
Post by: docmordrid on 06/27/2016 09:51 am
While they might build pieces of the BFR in Brownsville, getting the rocket to the pad would be difficult.  The shipping channel is separated from the launch site by several miles of wetlands.  Dredging a channel and building a dock and roadway to the pad would have to get past an awful lot of environmental and political hurdles.


Its 4.7 miles from the outlet, straight down the coast. IF they could get approval for a ramp or pier from the end of Rte 4 they could unload it from a crane barge.

Quote
Then there's the other big issue: where are you going to test-fire this thing?  McGregor can't do it. 
>

You could blow a 5 kiloton nuke over the pad and maybe have enough overpressure to break windows at the village (~1.5 psi.) NASA rated Saturn V at about half a kiloton, an order of magnitude less, and explosive effects do not scale linearly at a distance. Others here have estimated BFRs blast as about 1.4x that of a Falcon Heavy going boom. A test fire would be far less than either, and pointed out at sea.
Title: Re: Where will BFR launch from?
Post by: Nomadd on 06/27/2016 03:36 pm
 I've eliminated the biggest obstacle for building a BFR size assembly hangar near the pad by checking the angles from my living room window and determining it won't block my view of the rocket. Everything else is details.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/27/2016 04:51 pm
While they might build pieces of the BFR in Brownsville, getting the rocket to the pad would be difficult.  The shipping channel is separated from the launch site by several miles of wetlands.  Dredging a channel and building a dock and roadway to the pad would have to get past an awful lot of environmental and political hurdles.


Its 4.7 miles from the outlet, straight down the coast. IF they could get approval for a ramp or pier from the end of Rte 4 they could unload it from a crane barge.

Why would they build stages in Brownsville and then barge them to Boca Chica? If they are only going about 16 miles down Route 4 to the pad, road transport is straightforward.

Testing is a bit of a issue, but I wonder if BFR will even do full duration firings once they start flying often. If they can just test individual engines at McGregor and do a short static firing on the pad then they may not need a huge test stand.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/27/2016 04:55 pm
They'll want to at least do long static test firings at the launch site (if they don't do test firings at a separate test site). The Soviets' N-1 program failed because they didn't do adequate ground testing (because they couldn't afford to do so), and so every time they had a problem, they discovered it via a huge explosion and a loss of vehicle instead of just a glitch on the test stand.
Title: Re: Where will BFR launch from?
Post by: docmordrid on 06/27/2016 04:57 pm


While they might build pieces of the BFR in Brownsville, getting the rocket to the pad would be difficult.  The shipping channel is separated from the launch site by several miles of wetlands.  Dredging a channel and building a dock and roadway to the pad would have to get past an awful lot of environmental and political hurdles.


Its 4.7 miles from the outlet, straight down the coast. IF they could get approval for a ramp or pier from the end of Rte 4 they could unload it from a crane barge.

Why would they build stages in Brownsville and then barge them to Boca Chica? If they are only going about 16 miles down Route 4 to the pad, road transport is straightforward.
>

To minimize blocking and damage to Rte 4, which locals are already screaming about with the construction. ISTM improving Rte 4's  end for barge unloading could be cheaper and less intrusive.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/27/2016 05:06 pm


While they might build pieces of the BFR in Brownsville, getting the rocket to the pad would be difficult.  The shipping channel is separated from the launch site by several miles of wetlands.  Dredging a channel and building a dock and roadway to the pad would have to get past an awful lot of environmental and political hurdles.


Its 4.7 miles from the outlet, straight down the coast. IF they could get approval for a ramp or pier from the end of Rte 4 they could unload it from a crane barge.

Why would they build stages in Brownsville and then barge them to Boca Chica? If they are only going about 16 miles down Route 4 to the pad, road transport is straightforward.
>

To minimize blocking and damage to Rte 4, which locals are already screaming about with the construction. ISTM improving Rte 4's  end for barge unloading could be cheaper and less intrusive.
How often would you be transporting rockets from the factory? Not very often, as the rockets are reusable. Orders of magnitude less often than the construction trucks on Rte 4.

When it's time for launches every hour, they'll need to have a new launch site anyway, so they can improve barge access at that time.
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/27/2016 06:55 pm
They'll want to at least do long static test firings at the launch site (if they don't do test firings at a separate test site). The Soviets' N-1 program failed because they didn't do adequate ground testing (because they couldn't afford to do so), and so every time they had a problem, they discovered it via a huge explosion and a loss of vehicle instead of just a glitch on the test stand.

During early development I'm sure they will do exactly that, by either firing them on the pad, building a test stand nearby, or barging them somewhere else (Stennis?) to test fire. I doubt that will be SOP once the launch rate builds up though. Once they launch and recover boosters several time, they might decide to stick with static firings and individual engine testing.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/27/2016 07:26 pm
They'll want to at least do long static test firings at the launch site (if they don't do test firings at a separate test site). The Soviets' N-1 program failed because they didn't do adequate ground testing (because they couldn't afford to do so), and so every time they had a problem, they discovered it via a huge explosion and a loss of vehicle instead of just a glitch on the test stand.

During early development I'm sure they will do exactly that, by either firing them on the pad, building a test stand nearby, or barging them somewhere else (Stennis?) to test fire. I doubt that will be SOP once the launch rate builds up though. Once they launch and recover boosters several time, they might decide to stick with static firings and individual engine testing.
Agreed, except I think they might just test them on the launch pad instead of building a separate test stand or shipping them to Stennis. Stennis is unlikely to have a test stand big enough for the 15 million pound thrust BFR.
Title: Re: Where will BFR launch from?
Post by: darkenfast on 06/27/2016 08:00 pm
There's also a lot of difference between a launch pad and a test stand that can do a full duration firing.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/28/2016 11:32 am
There's also a lot of difference between a launch pad and a test stand that can do a full duration firing.
If you're talking /minimum/ requirements, sure. But Antares, for instance, does very long static fires on it's launch pad. And Shuttle has done long tests (without boosters, of course) on its launch pad as well.

So the idea definitely isn't absurd and is probably one of the options SpaceX is considering.
Title: Re: Where will BFR launch from?
Post by: darkenfast on 06/28/2016 12:05 pm
There's also a lot of difference between a launch pad and a test stand that can do a full duration firing.
If you're talking /minimum/ requirements, sure. But Antares, for instance, does very long static fires on it's launch pad. And Shuttle has done long tests (without boosters, of course) on its launch pad as well.

So the idea definitely isn't absurd and is probably one of the options SpaceX is considering.
BFR will need some FULL-DURATION testing.  Antares is smaller than even Falcon 9 and as far as I know has not done a full-duration firing on that pad.  Shuttle's Main Engines totaled less than the newer versions of Falcon 9 and it was ballasted by the SRBs.  A full duration  firing of the BFR would be like running four+ SRBs to depletion vertically on LC39.  During that testing, Boca Chica would be out of service for anything else.  During that testing and launches, what happens to anyone living within about, say, four miles of the site?  Do you seriously think that Spacex would be allowed to operate the most powerful rocket ever built within the current range of the houses in the village?  And, again: how are you going to get the rocket there?  Docmordrid suggested building a pier at the end of the road.  Well, for starters, that is a State Beach.  You want to build a road out across that beach and then build a pier out into the open ocean far enough to be able to moor a barge and transfer the rocket across the beach and to a launch pad?  And where is the pad?  Right next to the bustling (we hope) Falcon 9/Heavy pad?  Notice how much work is having to be done to build up the ground for that Falcon pad?  How much more will have to be done to build a BFR Assembly and Launch Complex on that soil.

There are too many problems with Boca Chica as a BFR launch site that can't be simply hand-waved away.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/28/2016 12:28 pm
Yes, I do. Falcon Heavy will be nearly the most powerful rocket, and it will be operating from there. Additionally, a launch is much louder than a test because it's unshielded.

If BFR is going to be launched from Boca Chica (possible, but not established), then you could test it there.

Remember that SpaceX has 3 other launch sites to launch from. It's not like Boca Chica is the only option for commercial vehicles.

Of course, if Boca Chica isn't going to launch BFR, then there'd be no reason to test it there.

Don't confuse the issues, here. And asking a whole bunch of questions at once is not sign of having a good point, it's just poor form designed to obfuscate the issue.

You can't hand-wave something a way just by asking a bunch of repetitive questions, many of which have already been answered or which are making assumptions about what my point is.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/28/2016 12:38 pm
There's also a lot of difference between a launch pad and a test stand that can do a full duration firing.
If you're talking /minimum/ requirements, sure. But Antares, for instance, does very long static fires on it's launch pad. And Shuttle has done long tests (without boosters, of course) on its launch pad as well.

So the idea definitely isn't absurd and is probably one of the options SpaceX is considering.
BFR will need some FULL-DURATION testing.  Antares is smaller than even Falcon 9 and as far as I know has not done a full-duration firing on that pad.  Shuttle's Main Engines totaled less than the newer versions of Falcon 9 and it was ballasted by the SRBs.  A full duration  firing of the BFR would be like running four+ SRBs to depletion vertically on LC39.  During that testing, Boca Chica would be out of service for anything else.  During that testing and launches, what happens to anyone living within about, say, four miles of the site?  Do you seriously think that Spacex would be allowed to operate the most powerful rocket ever built within the current range of the houses in the village?  And, again: how are you going to get the rocket there?  Docmordrid suggested building a pier at the end of the road.  Well, for starters, that is a State Beach.  You want to build a road out across that beach and then build a pier out into the open ocean far enough to be able to moor a barge and transfer the rocket across the beach and to a launch pad?  And where is the pad?  Right next to the bustling (we hope) Falcon 9/Heavy pad?  Notice how much work is having to be done to build up the ground for that Falcon pad?  How much more will have to be done to build a BFR Assembly and Launch Complex on that soil.

There are too many problems with Boca Chica as a BFR launch site that can't be simply hand-waved away.

You're asking a whole bunch of questions to /bury/ the issue, not to actually have any of them answered.

Most of your questions apply to Falcon Heavy, and yet they're going to fly Falcon Heavy anyway.

Do you actually want to look at the question of doing test firings at Boca Chica, or do you just want to shut down conversation?
Title: Re: Where will BFR launch from?
Post by: envy887 on 06/28/2016 01:25 pm
1. BFR will need some FULL-DURATION testing.  Antares is smaller than even Falcon 9 and as far as I know has not done a full-duration firing on that pad.  Shuttle's Main Engines totaled less than the newer versions of Falcon 9 and it was ballasted by the SRBs.  A full duration  firing of the BFR would be like running four+ SRBs to depletion vertically on LC39. 

2. During that testing, Boca Chica would be out of service for anything else. 

3. During that testing and launches, what happens to anyone living within about, say, four miles of the site?  Do you seriously think that Spacex would be allowed to operate the most powerful rocket ever built within the current range of the houses in the village? 

4. And, again: how are you going to get the rocket there?  Docmordrid suggested building a pier at the end of the road.  Well, for starters, that is a State Beach.  You want to build a road out across that beach and then build a pier out into the open ocean far enough to be able to moor a barge and transfer the rocket across the beach and to a launch pad? 

5. And where is the pad?  Right next to the bustling (we hope) Falcon 9/Heavy pad? 

6. Notice how much work is having to be done to build up the ground for that Falcon pad?  How much more will have to be done to build a BFR Assembly and Launch Complex on that soil.

7. There are too many problems with Boca Chica as a BFR launch site that can't be simply hand-waved away.

1. Define "some". How many full-duration firings of a full stage do you think there will be? I think there will be at most 5 or 10 over the course of a year or two; all other qualifications will be handled with short(er)-duration firings and individual engine testing.

2. This is SOP at other ranges during launches or test firings. Don't see why it's an issue for a couple full-length firings a year.

3. "Anyone living within 4 miles" is less than 10 people; the "village" is mostly beach houses. As for what happens to them, probably nothing. During full-duration testing, most of the acoustic energy could be directed out over the Gulf by the flame trench. The noise would probably be similar in magnitude (though longer in duration) to a Falcon Heavy launch. Even a full on-pad explosion wouldn't do much more than break some windows at that distance.

4. Tow it down Route 4, just like Falcon 9 and Heavy. No reason to barge it somewhere with easy road access.

5. That's an excellent question. And the answer is probably yes. Right next to the Falcon pad, which will have one or two launches a month.

6. Heavy is already 1200 tonnes and 12 meters across. The BFR pad will require some more work, but not an order of magnitude more. Perhaps twice as much, probably over a longer period of time.

7. Those problems exist everywhere. SpaceX arrived at Boca Chica after a exhaustive process of elimination. There aren't a lot of better sites, so all these problems will have to be solved if BFR will ever launch anything.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 06/28/2016 05:21 pm
To provide something of an historical perspective, in 1961, when a fledgling NASA was told to send Apollo to the Moon within eight years, a task force was assembled to decide where they would build the needed launch facilities.  They were looking at flying anything and everything from Saturn C-I's to Saturn C-2's to Novas, at possible launch cadences from once every week or two for the smaller variants, to once or twice a year for the Novas.

The first option anyone looked at, of course, was Cape Canaveral and its immediate environs.  This developed into a long laundry list to prove why the Cape was the worst place in the world to even consider siting Apollo launch facilities.  Many of the items on that laundry list also appear on people's lists here who argue against launching the BFR from Boca Chica.

In the end, NASA did site surveys and detailed investigations into nearly a dozen potential launch sites, ranging from Hawaii to Christmas Island to Wallops to (ahem) the Brownsville region.

Their conclusion?  The Cape was "the worst place in the world to launch from -- except for everywhere else."

Of course, that was back when the entire Merritt Island area was nothing but salt scrub.  And before the era of the EPA and Environmental Impact Statements.  So, there were a lot of attractive things about the site, as well -- maybe especially the existence of the Eastern Range with its tracking assets already in place.

My point isn't that the Cape is a better place to launch the BFR from than Boca Chica.  My point is that, once you identify a list of potential sites, you can't go into the selection process by saying "Which site has no issues of any kind?" because such things live in a magical cave with Santa Claus and the Easter Bunny.  You list, collate and compare all of the issues with all of the various potential sites, and you decide which issues are tractable and which aren't.  You then make your selection based on which site has the least intractable issues and has no show-stoppers.

I still think that, at least for the first major BFR launch site, Boca Chica will end up being the site that's the worst site in the world for it -- except for all of the rest of them... :)
Title: Re: Where will BFR launch from?
Post by: Lars-J on 06/28/2016 05:47 pm
And yet Shotwell hinted the BFR will have to be built on the pad...perhaps because they're making it without a mono tank?  Multiple road transportable tanks?  Are you all betting on massive tanks the full size of the diameter?

Sigh, no. Not *on the pad*. You misunderstand.
Title: Re: Where will BFR launch from?
Post by: darkenfast on 06/28/2016 09:10 pm
There's also a lot of difference between a launch pad and a test stand that can do a full duration firing.
If you're talking /minimum/ requirements, sure. But Antares, for instance, does very long static fires on it's launch pad. And Shuttle has done long tests (without boosters, of course) on its launch pad as well.

So the idea definitely isn't absurd and is probably one of the options SpaceX is considering.
BFR will need some FULL-DURATION testing.  Antares is smaller than even Falcon 9 and as far as I know has not done a full-duration firing on that pad.  Shuttle's Main Engines totaled less than the newer versions of Falcon 9 and it was ballasted by the SRBs.  A full duration  firing of the BFR would be like running four+ SRBs to depletion vertically on LC39.  During that testing, Boca Chica would be out of service for anything else.  During that testing and launches, what happens to anyone living within about, say, four miles of the site?  Do you seriously think that Spacex would be allowed to operate the most powerful rocket ever built within the current range of the houses in the village?  And, again: how are you going to get the rocket there?  Docmordrid suggested building a pier at the end of the road.  Well, for starters, that is a State Beach.  You want to build a road out across that beach and then build a pier out into the open ocean far enough to be able to moor a barge and transfer the rocket across the beach and to a launch pad?  And where is the pad?  Right next to the bustling (we hope) Falcon 9/Heavy pad?  Notice how much work is having to be done to build up the ground for that Falcon pad?  How much more will have to be done to build a BFR Assembly and Launch Complex on that soil.

There are too many problems with Boca Chica as a BFR launch site that can't be simply hand-waved away.

You're asking a whole bunch of questions to /bury/ the issue, not to actually have any of them answered.

Most of your questions apply to Falcon Heavy, and yet they're going to fly Falcon Heavy anyway.

Do you actually want to look at the question of doing test firings at Boca Chica, or do you just want to shut down conversation?

I am not trying to shut down the discussion and I do not appreciate the accusation. 

The subject of this thread is "Where will the BFR launch from?" and I have not seen evidence that Boca Chica is the obvious choice, vice testing at Stennis and launching at KSC.  The only question that has been possibly answered to my satisfaction is that the BFR could be trucked down the road.  Perhaps Nomadd, who lives there, can give us his thoughts on whether a 10-15m wide cylinder can be brought down from the nearest appropriate site to build a factory. 

Falcon Heavy is not the same thing as the BFR.  There is a big difference in power.  I also have not seen any indications that SpaceX plans to do a full-duration test of Falcon heavy on the pad at Boca Chica.

No site is going to be perfect and no launch site is going to be cheap.  My point is that this site (or any other candidate site), does not exist in a vacuum.  There are issues to be considered.

Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/29/2016 12:36 am
Much more reasonable post, thank you.

Falcon Heavy will have 5 times the power of the original Falcon 9. BFR will have 3-4 times Falcon Heavy. But this energy is distributed over a sphere not that much greater in diameter.

I don't know why you'd test fire at Stennis, or you're defeating the whole point of building your factory near the launch site.
Title: Re: Where will BFR launch from?
Post by: chalz on 06/29/2016 08:29 am
They intend to static fire FH in Texas from a sunken horizontal stand to mitigate noise issues. At Boca Chica could they make a horizontal stand but slightly elevated and pointing out to sea? Elevated to avoid damage to the beach. Or do I misunderstand the acoustic and turbulence effects?
Title: Re: Where will BFR launch from?
Post by: BobHk on 06/29/2016 08:28 pm
Boca (Brownsville and surrounding counties)  is likely to be the first BFR manufacturing area (My opinion/guess) and launch site (again my opinion but Musk sites his facilities nearest the most needed resources - Gigafactory is near a brine lithium deposit which means unlike asiian batt mfgs he doesn't have to have all his lithium shipped in from eastern china or south america; Boca is near a lot of very accessible methane).  It can't (probably) be the only one because Musk has indicated many many ships will go each synod when things are really rolling.   But if a hundred launch pads sprout there in the next twenty years because its a convenient launch location will I be surprised?  Nope.

Title: Re: Where will BFR launch from?
Post by: envy887 on 06/29/2016 08:53 pm
...But if a hundred launch pads sprout there in the next twenty years because its a convenient launch location will I be surprised?  Nope.

Hundreds of pads would mean hourly launches and landings with multiple sonic booms, all of which is going to add up to an incredible amount of noise. SpaceX would probably have to buy out all the local residents.

I think that launch rate will require very large dedicated offshore platforms.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/29/2016 09:25 pm
...But if a hundred launch pads sprout there in the next twenty years because its a convenient launch location will I be surprised?  Nope.

Hundreds of pads would mean hourly launches and landings with multiple sonic booms, all of which is going to add up to an incredible amount of noise. SpaceX would probably have to buy out all the local residents.

I think that launch rate will require very large dedicated offshore platforms.
Agreed. And I don't think that SpaceX will slow down the development of their first BFR launch site just to make sure it's "perfect" and ideally suited to the future of hourly launches.

SpaceX will do what they always have and build quickly then iterate from there, perhaps move to another launch site (remember that they've built or are building 6 different launch sites in the past, 2 of which were for Falcon 1 and have already been abandoned... even LC39A only has a 20 year lease (of which only 18 are left), but they built their biggest launch vehicle integration facility yet on the site (the enormous HIF) right on the crawlerway. They're not afraid of temporary solutions.

So whether Boca Chica, some place near KSC or CCAFB, or some other place, we shouldn't expect the first BFR launch site to be their last.
Title: Re: Where will BFR launch from?
Post by: Nomadd on 06/29/2016 10:15 pm
 Maybe Boca Chica isn't the obvious choice, but I know at least three of us have talked to SpaceX engineers who are clearly under instructions not to say anything, but are just as clearly excited about the possibility of the new site being BFRs home. I don't even know if they're going to assemble the FH at the control center area or the pad warehouse, much less how the big one would work. If they do start hauling 50 foot wide rockets, a causeway built parallel to the highway seems like a better idea that using the road.
 Trying to figure if they'd need separate pads and assembly buildings involves a lot of assumptions and guesswork right now. The vehicle buildings they're about to build look about 120ft wide, and will be "50-65ft" tall. If they're 65ft with 60ft tall doors, that might be a hint.
 If they want to do a major expansion, the west side of the little Boca Chica bay north of the pad warehouse seems like a better spot than the pad they're building now. It would help avoid trouble with the turtles and plovers and other critters on the beach that people are worried about and will avoid getting too close to Mexico. There's not much in that part of the state park besides rattlers, mosquitoes and some old guy launching his kayak in the mornings.
Title: Re: Where will BFR launch from?
Post by: darkenfast on 06/30/2016 03:20 am
It's not a kayak, it's a NASASpaceflight Intelligence Directorate (Boca Chica Detachment) Reconnaissance Vessel.
Title: Re: Where will BFR launch from?
Post by: llanitedave on 06/30/2016 02:12 pm
It's not a kayak, it's a NASASpaceflight Intelligence Directorate (Boca Chica Detachment) Reconnaissance Vessel.

Which needs to be drydocked regularly for inspection.
Title: Re: Where will BFR launch from?
Post by: Semmel on 06/30/2016 02:27 pm
The best argument for Boca Chica being the launch site for BFR is the lack of other launch site construction projects by SpaceX that we are aware of. I find it hard to believe that Boca Chica is solely for Falcon launches and that SpaceX would create yet an other site for BFR. But that's not based on evidence, it just feels right.
Title: Re: Where will BFR launch from?
Post by: guckyfan on 06/30/2016 02:48 pm
The best argument for Boca Chica being the launch site for BFR is the lack of other launch site construction projects by SpaceX that we are aware of. I find it hard to believe that Boca Chica is solely for Falcon launches and that SpaceX would create yet an other site for BFR. But that's not based on evidence, it just feels right.

I too thought of Brownsville as the location of choice for SpaceX. I don't see any chance however to get permissions to build in time to meet their launch date of 2024. That would need a pad ready by 2020 to accomodate all necessary tests.
2024 is an aspirational date, I know but they must see at least a small chance to meet it. So Brownsville may still be their location of choice for a colonization drive but they must have something where they can build for 2020/21.

So while the Cape would not be optimal, having it first and use it later as a backup and for NASA and DOD launches could be a good plan.
Title: Re: Where will BFR launch from?
Post by: whitelancer64 on 06/30/2016 02:50 pm
The best argument for Boca Chica being the launch site for BFR is the lack of other launch site construction projects by SpaceX that we are aware of. I find it hard to believe that Boca Chica is solely for Falcon launches and that SpaceX would create yet an other site for BFR. But that's not based on evidence, it just feels right.

I guess we'll know if we find out that the Boca Chica site is being massively overbuilt if it were just meant to launch Falcon 9 and Falcon Heavy rockets.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/30/2016 03:37 pm
But how much is really actually required for BFR?
Title: Re: Where will BFR launch from?
Post by: DigitalMan on 06/30/2016 03:49 pm
It's a horrible idea to build out the pad at Boca Chica to handle BFR when they haven't the approvals for it.
Title: Re: Where will BFR launch from?
Post by: whitelancer64 on 06/30/2016 05:03 pm
But how much is really actually required for BFR?

Supposedly, BFR will have much more thrust than the Saturn V (speculation varies of course, but if there are 30 Raptors on the first stage and the Raptor has a sea-level thrust of 517,000 lbf (number from wikipedia), that means the BFR has a first stage sea-level thrust of 15.51 million lbf, which is twice that of the Saturn V), and we know LC-39A isn't capable of handling the acoustic, etc. forces from that much thrust (at least not more than once, after which it would have to be pretty much rebuilt). So the BFR launch site will have to be more robustly built than LC-39A, at minimum.
Title: Re: Where will BFR launch from?
Post by: Nomadd on 06/30/2016 05:19 pm
It's a horrible idea to build out the pad at Boca Chica to handle BFR when they haven't the approvals for it.
Why would spending a few million now to make the pad more capable be a horrible idea when it could save them years worth of time? If they can't get approval in Texas, I doubt if they'd get it anywhere. You can't always wait for one thing to happen to start the next step. Sometimes you have to make your best bet and hope it will work the way you plan. They don't have to have the pad capable of launching BFRs today. They just need to make the underlying substructure capable of taking the mods needed in the future without tearing the whole hill up.
Title: Re: Where will BFR launch from?
Post by: wannamoonbase on 06/30/2016 05:46 pm
Florida, specifically LC39A.

It's the only thing that makes sense.

Consider NASA and DOD payloads, as they will be the big dollar clients.

I think the BFR structure and it's integration should be done at CCAFS as well.
Title: Re: Where will BFR launch from?
Post by: guckyfan on 06/30/2016 05:59 pm
It's a horrible idea to build out the pad at Boca Chica to handle BFR when they haven't the approvals for it.
Why would spending a few million now to make the pad more capable be a horrible idea when it could save them years worth of time?

Do you think the EPA will take kindly to that line of action? It might make approval a lot less likely.
Title: Re: Where will BFR launch from?
Post by: whitelancer64 on 06/30/2016 06:07 pm
Florida, specifically LC39A.

It's the only thing that makes sense.

Consider NASA and DOD payloads, as they will be the big dollar clients.

I think the BFR structure and it's integration should be done at CCAFS as well.

Unless the BFR is not so much of a BFR as it is speculated to be, LC-39A will not be able to handle the forces from the thrust from the BFR. If the BFR is roughly the size / thrust levels of the Saturn V, then LC-39A will be fine.
Title: Re: Where will BFR launch from?
Post by: docmordrid on 06/30/2016 07:10 pm
In an AskMen interview Musk quoted 15 million lbf, 2x Saturn V,

http://www.askmen.com/entertainment/right-stuff/elon-musk-interview.html

Quote
The rockets will get even bigger. “We’re looking at our Mars transporter being around 15 million pounds of thrust,” says Musk. “And that one will switch to methane [fuel] for a high specific impulse system.”

and others here have stated 39A is only rated for 12 million lbf.  In a GQ interview last December he again  made it quite clear BFR is very large. Then there's L2.

http://www.gq.com/story/elon-musk-mars-spacex-tesla-interview

Quote
He laughs. "It's really big." And laughs again. "It's really big. There's not been any architecture like this described that I'm aware of."



Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/30/2016 07:39 pm
But how much is really actually required for BFR?

Supposedly, BFR will have much more thrust than the Saturn V (speculation varies of course, but if there are 30 Raptors on the first stage and the Raptor has a sea-level thrust of 517,000 lbf (number from wikipedia), that means the BFR has a first stage sea-level thrust of 15.51 million lbf, which is twice that of the Saturn V), and we know LC-39A isn't capable of handling the acoustic, etc. forces from that much thrust (at least not more than once, after which it would have to be pretty much rebuilt). So the BFR launch site will have to be more robustly built than LC-39A, at minimum.
What does "robustly" mean?

It's most certainly /possible/, that it doesn't necessarily require a much heavier launch pad. Bigger acoustic suppression systems, bigger flame trench, etc... Yes.

By the way, it's not speculation that SpaceX (Shotwell/Musk) have said BFR will have 15 million lbf thrust.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/30/2016 07:40 pm
In an AskMen interview Musk quoted 15 million lbf, 2x Saturn V,

http://www.askmen.com/entertainment/right-stuff/elon-musk-interview.html

Quote
The rockets will get even bigger. “We’re looking at our Mars transporter being around 15 million pounds of thrust,” says Musk. “And that one will switch to methane [fuel] for a high specific impulse system.”

and others here have stated 39A is only rated for 12 million lbf.  In a GQ interview last December he again  made it quite clear BFR is very large. Then there's L2.

http://www.gq.com/story/elon-musk-mars-spacex-tesla-interview

Quote
He laughs. "It's really big." And laughs again. "It's really big. There's not been any architecture like this described that I'm aware of."
Specificially, it's the flame trench that I believe is the limiting factor for 39a.
Title: Re: Where will BFR launch from?
Post by: whitelancer64 on 06/30/2016 08:12 pm
But how much is really actually required for BFR?

Supposedly, BFR will have much more thrust than the Saturn V (speculation varies of course, but if there are 30 Raptors on the first stage and the Raptor has a sea-level thrust of 517,000 lbf (number from wikipedia), that means the BFR has a first stage sea-level thrust of 15.51 million lbf, which is twice that of the Saturn V), and we know LC-39A isn't capable of handling the acoustic, etc. forces from that much thrust (at least not more than once, after which it would have to be pretty much rebuilt). So the BFR launch site will have to be more robustly built than LC-39A, at minimum.
What does "robustly" mean?

It's most certainly /possible/, that it doesn't necessarily require a much heavier launch pad. Bigger acoustic suppression systems, bigger flame trench, etc... Yes.

By the way, it's not speculation that SpaceX (Shotwell/Musk) have said BFR will have 15 million lbf thrust.

"Bigger acoustic suppression systems, bigger flame trench"

Yes, but all the on-pad equipment will need greater levels of reinforcement or protection as well. The size and construction of the flame trench at the LC-39 pads is probably the biggest issue, as you mention in your other post. I'm given to understand some of the the brickwork that lines the flame trenches got broken up from time to time even during Shuttle launches, I'm sure a BFR would tear it up completely.
Title: Re: Where will BFR launch from?
Post by: wannamoonbase on 06/30/2016 08:44 pm
I think there will be a smaller Raptor powered vehicle before there is ever a 15 million lbf rocket.

The smaller (relative term) vehicle that can create a commercial revenue flow.  Maybe this is some tiny rocket with 2.5 to 7.5 lbf.  (I like the idea of a 5 engine Raptor core (2.5 million lbf) with a 3 core configuration (7.5 million lbf) like FH, with cross-feed ideally)

Regardless it makes sense that any of these vehicles fly from KSC/CCAFS as that is where NASA and DOD have people and facilities. 

Also, massive stretches of land for new pads and safety area in case things go 'poorly'.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 06/30/2016 09:01 pm
I think there will be a smaller Raptor powered vehicle before there is ever a 15 million lbf rocket.

The smaller (relative term) vehicle that can create a commercial revenue flow.  Maybe this is some tiny rocket with 2.5 to 7.5 lbf.  (I like the idea of a 5 engine Raptor core (2.5 million lbf) with a 3 core configuration (7.5 million lbf) like FH, with cross-feed ideally)

Regardless it makes sense that any of these vehicles fly from KSC/CCAFS as that is where NASA and DOD have people and facilities. 

Also, massive stretches of land for new pads and safety area in case things go 'poorly'.
Sure, but does ANY of that have any hint at all from SpaceX?
Title: Re: Where will BFR launch from?
Post by: Bob Shaw on 06/30/2016 09:20 pm
I'm given to understand some of the the brickwork that lines the flame trenches got broken up from time to time even during Shuttle launches, I'm sure a BFR would tear it up completely.

'Broken up'? Absolutely wrecked, with individual bricks travelling hundreds of meters through the air. A brick flying through the wall of an ET would have been a bad day indeed. 1,500 bricks flew up to half a kilometer from the flame trench on 31 May 2008.

https://www.nasaspaceflight.com/2016/05/renewing-famous-flame-trench-brick-time/

Title: Re: Where will BFR launch from?
Post by: DigitalMan on 06/30/2016 11:44 pm
But how much is really actually required for BFR?

Supposedly, BFR will have much more thrust than the Saturn V (speculation varies of course, but if there are 30 Raptors on the first stage and the Raptor has a sea-level thrust of 517,000 lbf (number from wikipedia), that means the BFR has a first stage sea-level thrust of 15.51 million lbf, which is twice that of the Saturn V), and we know LC-39A isn't capable of handling the acoustic, etc. forces from that much thrust (at least not more than once, after which it would have to be pretty much rebuilt). So the BFR launch site will have to be more robustly built than LC-39A, at minimum.
What does "robustly" mean?

It's most certainly /possible/, that it doesn't necessarily require a much heavier launch pad. Bigger acoustic suppression systems, bigger flame trench, etc... Yes.

By the way, it's not speculation that SpaceX (Shotwell/Musk) have said BFR will have 15 million lbf thrust.

"Bigger acoustic suppression systems, bigger flame trench"

Yes, but all the on-pad equipment will need greater levels of reinforcement or protection as well. The size and construction of the flame trench at the LC-39 pads is probably the biggest issue, as you mention in your other post. I'm given to understand some of the the brickwork that lines the flame trenches got broken up from time to time even during Shuttle launches, I'm sure a BFR would tear it up completely.

Not only broken up, when I was on the up close tour a while back you could see them in the fence
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/01/2016 12:14 am
You could make it out of steel instead.
Title: Re: Where will BFR launch from?
Post by: Ludus on 07/01/2016 10:18 pm
You could make it out of steel instead.

I've got no clue what engineering issues are involved but this sort of question is what occurs to me. Wouldn't it be cheaper to armor an existing flame trench with steel plates?
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/01/2016 10:21 pm
You could make it out of steel instead.

I've got no clue what engineering issues are involved but this sort of question is what occurs to me. Wouldn't it be cheaper to armor an existing flame trench with steel plates?
If you're building a new flame trench anyway (which is what they're doing at Boca Chica), it'd be cheaper to build it the first time than to retrofit.
Title: Re: Where will BFR launch from?
Post by: Ludus on 07/01/2016 11:00 pm
You could make it out of steel instead.

I've got no clue what engineering issues are involved but this sort of question is what occurs to me. Wouldn't it be cheaper to armor an existing flame trench with steel plates?
If you're building a new flame trench anyway (which is what they're doing at Boca Chica), it'd be cheaper to build it the first time than to retrofit.

Sure. If armoring a launch pad flame trench with steel plates lets it function for much higher thrust rockets it would probably be better to bake it into the initial design than retro-fit it. Steel plates are comparatively cheap next to other issues. Designing it that way is cheaper than adapting it.

Title: Re: Where will BFR launch from?
Post by: Ludus on 07/01/2016 11:11 pm
I have no idea how such designs are evaluated but intuitively it seems like a a flame trench that has steel plate armor would work pretty well. The plates would resist mechanical forces much better than masonry and temperature stresses would be very brief. That much steel plate would certainly cost in the 10's of millions of dollars but that's not a big deal in this case.
Title: Re: Where will BFR launch from?
Post by: Thorny on 07/01/2016 11:19 pm
I have no idea how such designs are evaluated but intuitively it seems like a a flame trench that has steel plate armor would work pretty well.

Rust?
Title: Re: Where will BFR launch from?
Post by: Ludus on 07/01/2016 11:57 pm
I have no idea how such designs are evaluated but intuitively it seems like a a flame trench that has steel plate armor would work pretty well.

Rust?

Nothing like 15 million pounds of thrust every now and then to scour it clean and shiny.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/02/2016 12:29 am
I have no idea how such designs are evaluated but intuitively it seems like a a flame trench that has steel plate armor would work pretty well. The plates would resist mechanical forces much better than masonry and temperature stresses would be very brief. That much steel plate would certainly cost in the 10's of millions of dollars but that's not a big deal in this case.
I'm not sure it'd cost that much. Steel is SUUUPER cheap right now. Like $500 per ton. If they need 2 or so thousand tons of steel (you're talking steel 2 inches thick... Probably overkill over most of the trench), that's only roughly a million dollars. So a few million should easily cover it for raw material costs.
Title: Re: Where will BFR launch from?
Post by: Impaler on 07/02/2016 03:57 am
Do we have any evidence that the thrust from the Raptor engine might be less damaging then other rockets?  Saturn V had very poor ISP so even though BFR will have nearly twice the thrust it's not necessarily twice the mass-flow rate which could significantly change how the flame trench handles the load.  On the other hand it might be worse due to the higher exhaust velocity.   Point is a linear extrapolation from thrust to the structural requirements of the pad may not be appropriate.
Title: Re: Where will BFR launch from?
Post by: Ludus on 07/02/2016 05:11 am
I have no idea how such designs are evaluated but intuitively it seems like a a flame trench that has steel plate armor would work pretty well. The plates would resist mechanical forces much better than masonry and temperature stresses would be very brief. That much steel plate would certainly cost in the 10's of millions of dollars but that's not a big deal in this case.
I'm not sure it'd cost that much. Steel is SUUUPER cheap right now. Like $500 per ton. If they need 2 or so thousand tons of steel (you're talking steel 2 inches thick... Probably overkill over most of the trench), that's only roughly a million dollars. So a few million should easily cover it for raw material costs.

Sounds fine to me. For less than $10M each SpaceX can put a lot of steel plate armor on the pads and flame trenches for both 39a and Boca Chica and the BFR is good to go.

Now we just need Jim or somebody to say: Wrong, it doesn't work like that.
Title: Re: Where will BFR launch from?
Post by: guckyfan on 07/02/2016 05:51 am
Do we have any evidence that the thrust from the Raptor engine might be less damaging then other rockets?  Saturn V had very poor ISP so even though BFR will have nearly twice the thrust it's not necessarily twice the mass-flow rate which could significantly change how the flame trench handles the load.  On the other hand it might be worse due to the higher exhaust velocity.   Point is a linear extrapolation from thrust to the structural requirements of the pad may not be appropriate.

We have repeated statements that LC-39A won't be able to handle BFR. For the moment I am going with that. All the better if it turns out wrong and some upgrades would make it capable of handling BFR.
Title: Re: Where will BFR launch from?
Post by: MP99 on 07/02/2016 10:03 am
Per earlier speculation, I find the option to launch from a pad at sea gets around these issues, possibly including full duration firings.

I wonder about an architecture like this:-

BFR launches from a pad some miles offshore.

S1 lands on another pad further downrange.

The pad makes its way back to Brownsville, where there is a dock complete with a vertical assembly tower. This is used to re-position S1 over the launch mounts, and stack BFS / tanker stage on top. The stage never goes horizontal during normal operations.

The factory would be on-site. New or refurbished stages would be delivered horizontally to the dock. If a returned stage needs refurbishment or repair, this is the only time the stage would be laid down horizontally.

The pad then goes to the launch location offshore. Once launch is complete, the pad makes its way to the landing area to collect another stage landing.

Basically, you have a bunch of pads, and they circulate to provide a conveyor belt for stages.


Alternate version:- separate launch and landing pads, each circulating. The vertical assembly tower would lift S1, landing pad would move away, launch pad would move in, S1 would be lowered and positioned, etc.


Downside of this architecture - it seems a bit too similar to the current ASDS operations.

Cheers, Martin
Title: Re: Where will BFR launch from?
Post by: geza on 07/02/2016 12:11 pm
The launch and the landing pad must be different. The launch pad need the have a hole for the exhaust and have to have a clamp down mechanism and equipment for fueling both stages. In contrast, the landing pad is supposed to be flat and clean. Take into account, that the fueled two-stage vehicle is extremely heavy. I cannot expect a floating pad to carry that weight. The launch pad must have legs to the bottom.
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/02/2016 01:25 pm
The launch and the landing pad must be different. The launch pad need the have a hole for the exhaust and have to have a clamp down mechanism and equipment for fueling both stages. In contrast, the landing pad is supposed to be flat and clean. Take into account, that the fueled two-stage vehicle is extremely heavy. I cannot expect a floating pad to carry that weight. The launch pad must have legs to the bottom.

Your intuition about weight is correct about rockets (BFR/BFS will indeed be very heavy, around 5000 tonnes), but off by several orders of magnitude about ships. An ASDS, which is relatively small for a ship, can carry over 10,000 tonnes, or roughly the equivalent of TWO fully fuelled BFR stacks. Each 5000 tonnes would only displace an ASDS about 1 meter into the water.

Large semisubmersible crane platforms can lift over 10,000 tonnes, and themselves weigh over 100,000 tonnes. Those types of floating platforms can very easily handle the weight of several rocket stacks, many launches worth of fuel, pads, erectors, support equipment, etc, etc.
Title: Re: Where will BFR launch from?
Post by: geza on 07/02/2016 01:52 pm
Thanks for correcting me!
Title: Re: Where will BFR launch from?
Post by: RonM on 07/02/2016 02:05 pm
The question is which would be cheaper, a ship/barge large enough to be used as a launch pad or a offshore platform? I'm guessing platform, but I'm not an expert on the subject.
Title: Re: Where will BFR launch from?
Post by: BobHk on 07/02/2016 03:52 pm
Per earlier speculation, I find the option to launch from a pad at sea gets around these issues, possibly including full duration firings.

I wonder about an architecture like this:-

BFR launches from a pad some miles offshore.

S1 lands on another pad further downrange.

The pad makes its way back to Brownsville, where there is a dock complete with a vertical assembly tower. This is used to re-position S1 over the launch mounts, and stack BFS / tanker stage on top. The stage never goes horizontal during normal operations.

The factory would be on-site. New or refurbished stages would be delivered horizontally to the dock. If a returned stage needs refurbishment or repair, this is the only time the stage would be laid down horizontally.

The pad then goes to the launch location offshore. Once launch is complete, the pad makes its way to the landing area to collect another stage landing.

Basically, you have a bunch of pads, and they circulate to provide a conveyor belt for stages.


Alternate version:- separate launch and landing pads, each circulating. The vertical assembly tower would lift S1, landing pad would move away, launch pad would move in, S1 would be lowered and positioned, etc.


Downside of this architecture - it seems a bit too similar to the current ASDS operations.

Cheers, Martin

Vertical assembly is very expensive.  SPACEX has avoided it for that reason.  I don't see them adopting vertical.
Title: Re: Where will BFR launch from?
Post by: pobermanns on 07/02/2016 04:15 pm
Per earlier speculation, I find the option to launch from a pad at sea gets around these issues, possibly including full duration firings.

I wonder about an architecture like this:-

BFR launches from a pad some miles offshore.

S1 lands on another pad further downrange.

The pad makes its way back to Brownsville, where there is a dock complete with a vertical assembly tower. This is used to re-position S1 over the launch mounts, and stack BFS / tanker stage on top. The stage never goes horizontal during normal operations.

The factory would be on-site. New or refurbished stages would be delivered horizontally to the dock. If a returned stage needs refurbishment or repair, this is the only time the stage would be laid down horizontally.

The pad then goes to the launch location offshore. Once launch is complete, the pad makes its way to the landing area to collect another stage landing.

Basically, you have a bunch of pads, and they circulate to provide a conveyor belt for stages.


Alternate version:- separate launch and landing pads, each circulating. The vertical assembly tower would lift S1, landing pad would move away, launch pad would move in, S1 would be lowered and positioned, etc.


Downside of this architecture - it seems a bit too similar to the current ASDS operations.

Cheers, Martin

Vertical assembly is very expensive.  SPACEX has avoided it for that reason.  I don't see them adopting vertical.
But in his scenario, MP99 speculates that the landed S1 would be brought on its barge/landing pad directly to the launch pad, still vertical. That means that if you're going to do horizontal integration, you have to rotate the S1 to horizontal. Is that easier than just stacking the whole thing vertically? If so, why is vertical assembly so expensive?
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/02/2016 05:09 pm
Vertical assembly is very expensive.  SPACEX has avoided it for that reason.  I don't see them adopting vertical.
But in his scenario, MP99 speculates that the landed S1 would be brought on its barge/landing pad directly to the launch pad, still vertical. That means that if you're going to do horizontal integration, you have to rotate the S1 to horizontal. Is that easier than just stacking the whole thing vertically? If so, why is vertical assembly so expensive?

BFR will almost certainly return the launch site (or more precisely, to near the integration facility), not land or barge downrange. That's the simplest way to do it, especially when flight rate ramps up.

And vertical integration requires a skyscraper for a integration facility. It's FAR easier to work on a 100-meter launcher when it's laying sideways. Plus, it FAR easier to roll out a 100 meter vehicle on its side and erect it at the pad. SpaceX will almost certainly do that.
Title: Re: Where will BFR launch from?
Post by: philw1776 on 07/02/2016 05:51 pm
Not so sure BFRs won't land downrange on a "droneship" {Barge REDACTED}.
Issue being a good fraction of a Km/sec used to negate and change the sign of the downrange velocity.  Payload penalty of a couple tens of tonnes.
Title: Re: Where will BFR launch from?
Post by: pobermanns on 07/02/2016 08:00 pm
Not so sure BFRs won't land downrange on a "droneship" {Barge REDACTED}.
Ah, sorry for bad terminology. My bad.  :(
Title: Re: Where will BFR launch from?
Post by: douglas100 on 07/02/2016 08:11 pm
Not so sure BFRs won't land downrange on a "droneship" {Barge REDACTED}.
Issue being a good fraction of a Km/sec used to negate and change the sign of the downrange velocity.  Payload penalty of a couple tens of tonnes.

That's true, but it's the only argument against RTLS. Operationally, RTLS is simpler, faster, requires no expenditure on downrange infrastructure and is unaffected by downrange weather. Cool and exciting as SpaceX's maritime ops are, I believe they would abandon them immediately if F9 had sufficient margin to carry the largest commercial payloads and fly back.

It's been stated a number of times that BFR will have around twice the thrust of the Saturn 5. If that's true, I would expect that it to have plenty of margin. Then RTLS will be the only mode for recovering the first stage. So I would expect the vehicle to launch and set down on land.
Title: Re: Where will BFR launch from?
Post by: ZachS09 on 07/02/2016 11:09 pm
We would need a bigger barge for the BFR's first stage if it's to conduct a barging. If it tried to land on OCISLY, it would crush the barge under its weight and sink it.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/03/2016 01:13 am
We would need a bigger barge for the BFR's first stage if it's to conduct a barging. If it tried to land on OCISLY, it would crush the barge under its weight and sink it.
Umm, no it wouldn't. Those Marmacs have lifted things an order of magnitude heavier than an empty BFR stage.
Title: Re: Where will BFR launch from?
Post by: joek on 07/03/2016 02:22 am
Not so sure BFRs won't land downrange on a "droneship" {Barge REDACTED}.
Issue being a good fraction of a Km/sec used to negate and change the sign of the downrange velocity.  Payload penalty of a couple tens of tonnes.

Depends on the trades between BFR (S1) and BFS (S2) capabilities.  A lofted trajectory would mitigate S1 RTLS penalty, but require more dV from BFS to get into LEO.  But by all indications BFS will likely be quite capable as it will need to do Earth LEO to Mars and Mars to Earth.

In short, try looking at the problem from the other direction.... Start with the capabilities BFS will require independent of BFR: Earth-Mars and Mars-Earth.
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/03/2016 02:33 am
We would need a bigger barge for the BFR's first stage if it's to conduct a barging. If it tried to land on OCISLY, it would crush the barge under its weight and sink it.
Umm, no it wouldn't. Those Marmacs have lifted things an order of magnitude heavier than an empty BFR stage.

An ASDS could easily hold a 5000 tonne fully fueled and loaded BFR / BFS stack. An empty BFR would be simple.
Title: Re: Where will BFR launch from?
Post by: wannamoonbase on 07/03/2016 04:51 am
Anyone that thinks the next SpaceX rocket after FH is a 15 meter, 15 million Lbf rocket is on some good stuff.
Title: Re: Where will BFR launch from?
Post by: mfck on 07/03/2016 06:51 am
Anyone that thinks the next SpaceX rocket after FH is a 15 meter, 15 million Lbf rocket is on some good stuff.
Yeah, it's called "known facts", but you'll have to wait for September 24 to take a hit from it.
Title: Re: Where will BFR launch from?
Post by: The Amazing Catstronaut on 07/03/2016 07:42 am
Anyone that thinks the next SpaceX rocket after FH is a 15 meter, 15 million Lbf rocket is on some good stuff.

And we intend to share it with you. I'll send you a baggie.

After all, it'll help get you that moon base you've always wanted.

If a company starts building hardware in support of a rocket of those dimensions (raptor) and has been consistently stating for a number of years they're going to build said rocket, and spending both money and intellectual capital on said rocket (weekly meetings of key company figures for a number of years), they're not doing it just to make shiny power points, and the rocket directly supports the founding goal of the company, you can be sure they're going to build the rocket or go bust trying. This isn't a concept car. This isn't a speculative presentation waiting for NASA to fund all the associated costs (which, of course, they wouldn't and rightfully so). There is no former analogue.

Just because something is unbelievable doesn't necessarily mean impossible or unlikely, although it may mean a reprioritisation of an individual's belief system. That might be mine, that might be yours. Either way, we'll know for sure this year.
Title: Re: Where will BFR launch from?
Post by: MP99 on 07/03/2016 10:05 am


Per earlier speculation, I find the option to launch from a pad at sea gets around these issues, possibly including full duration firings.

I wonder about an architecture like this:-

BFR launches from a pad some miles offshore.

S1 lands on another pad further downrange.

The pad makes its way back to Brownsville, where there is a dock complete with a vertical assembly tower. This is used to re-position S1 over the launch mounts, and stack BFS / tanker stage on top. The stage never goes horizontal during normal operations.

The factory would be on-site. New or refurbished stages would be delivered horizontally to the dock. If a returned stage needs refurbishment or repair, this is the only time the stage would be laid down horizontally.

The pad then goes to the launch location offshore. Once launch is complete, the pad makes its way to the landing area to collect another stage landing.

Basically, you have a bunch of pads, and they circulate to provide a conveyor belt for stages.


Alternate version:- separate launch and landing pads, each circulating. The vertical assembly tower would lift S1, landing pad would move away, launch pad would move in, S1 would be lowered and positioned, etc.


Downside of this architecture - it seems a bit too similar to the current ASDS operations.

Cheers, Martin

Vertical assembly is very expensive.  SPACEX has avoided it for that reason.  I don't see them adopting vertical.
But in his scenario, MP99 speculates that the landed S1 would be brought on its barge/landing pad directly to the launch pad, still vertical. That means that if you're going to do horizontal integration, you have to rotate the S1 to horizontal. Is that easier than just stacking the whole thing vertically? If so, why is vertical assembly so expensive?

Thanks, that's exactly my thinking.

There are three categories of elements to be integrated onto an S1:-

* BFS (possibly crewed and cargo variants).
* Tanker.
* Payloads under a fairing, EG CommSats.

BFS and tanker are simple cases - just a single item to be mated to S1. I suspect that it may be easier to load heavy items (Habs, rovers, etc) onto MCT while vertical, but that is an issue that would be resolved before final integration at the dock.

(While it is tempting to suggest that load paths are easier to accommodate if they are always in the vertical direction, I understand that dynamic loads of 1G+ need to be accommodated during launch, anyway.)

Also, the mechanism that secures S1 to the "upper element" is the quick release that will have to release during staging. Given the desire for high flight rates it would make sense to also design this for easy assembly / latching, and minimise touch labour. There may be an opportunity to test fire the release mechanisms (perhaps not all at once?), which would be an advantage.

For payloads such as CommSats under a fairing, there are considerations of maintaining power, aircon, etc, etc, between the time of integration with upper stage, and integration of the upper stage with S1. Maybe these follow a different path? Or these use a variant of BFS as a carrier which includes such services. Or have a two stage integration - S2, then encapsulated payload as per ULA.

One big question is whether, or how often, BFR S1 requires maintenance / touch labour before it's ready to be integrated with its upper element.

Cheers, Martin
Title: Re: Where will BFR launch from?
Post by: MP99 on 07/03/2016 10:15 am
The launch and the landing pad must be different. The launch pad need the have a hole for the exhaust and have to have a clamp down mechanism and equipment for fueling both stages. In contrast, the landing pad is supposed to be flat and clean. Take into account, that the fueled two-stage vehicle is extremely heavy. I cannot expect a floating pad to carry that weight. The launch pad must have legs to the bottom.

I did suggest a variant which accommodates this.

Alternate version:- separate launch and landing pads, each circulating. The vertical assembly tower would lift S1, landing pad would move away, launch pad would move in, S1 would be lowered and positioned, etc.

I agree re the legs. I would see legs built on the sea floor, and the launching pad positions and settles itself over these to make a stable launch platform.

BTW, I would expect the prop for the launch to be carried in tanks inside the pad barge. Possibly the subcooling infrastructure would be built into the launch site, and not required to be on the launch barges.

Cheers, Martin
Title: Re: Where will BFR launch from?
Post by: MP99 on 07/03/2016 10:25 am
Not so sure BFRs won't land downrange on a "droneship" {Barge REDACTED}.
Issue being a good fraction of a Km/sec used to negate and change the sign of the downrange velocity.  Payload penalty of a couple tens of tonnes.
My primary reason for suggesting offshore launch is because of noise constraints.

The rest of my suggestion comes from assuming efficiency benefits of allowing S1 to remain vertical at all times for rapid turnaround. While landing noise onshore is less of an issue per se, it needs to be somewhere with unobstructed access to the site where stages are integrated.

If this does result in a sea-bourne infrastructure, then individual flights have the choice to land close to shore for quick turnaround (the equivalent of RTLS), or far downrange to maximise payload.

For instance, that BFS would have a downrange landing, but tankers would use "RTLS".

Cheers, Martin
Title: Re: Where will BFR launch from?
Post by: Nomadd on 07/03/2016 03:00 pm

An ASDS could easily hold a 5000 tonne fully fueled and loaded BFR / BFS stack.
Not with a 4500 lbs/sq. ft. deck.
Title: Re: Where will BFR launch from?
Post by: guckyfan on 07/03/2016 03:24 pm

An ASDS could easily hold a 5000 tonne fully fueled and loaded BFR / BFS stack.
Not with a 4500 lbs/sq. ft. deck.

But that's not relevant. It can hold it landing, empty. It could hold it full with adequate support structure in place, but I don't see it launch from there yet.
Title: Re: Where will BFR launch from?
Post by: philw1776 on 07/03/2016 04:00 pm
Not so sure BFRs won't land downrange on a "droneship" {Barge REDACTED}.
Issue being a good fraction of a Km/sec used to negate and change the sign of the downrange velocity.  Payload penalty of a couple tens of tonnes.

Depends on the trades between BFR (S1) and BFS (S2) capabilities.  A lofted trajectory would mitigate S1 RTLS penalty, but require more dV from BFS to get into LEO.  But by all indications BFS will likely be quite capable as it will need to do Earth LEO to Mars and Mars to Earth.

In short, try looking at the problem from the other direction.... Start with the capabilities BFS will require independent of BFR: Earth-Mars and Mars-Earth.

All my BFS models posted here have the Delta V for LEO to Mars surface AND Mars surface to Earth return, albeit with 1/4th the cargo mass for Mars-Earth as Musk stated.  But even with a high Delta V upper stage BFS you still need a couple Km/sec from the BFR stage one.  Knocking off X.Y Km/sec for RTLS hurts payload to LEO.  Tens of tonnes.  I do not agree with the idea that tankers RTLS because you want max bulk propellant payload to LEO to minimize # of tanker flights.  Hauling a tanker upper stage back for another stacking on the offshore launch platform is not time critical for the 1st several years of flights.  Build a couple stripped down tanker BFS shells and rotate them.  Later on, may be quite a different matter as the vehicles evolve and the architecture transitions to possible SEP interplanetary cargo transit.
Title: Re: Where will BFR launch from?
Post by: cartman on 07/03/2016 04:48 pm
The launch and the landing pad must be different. The launch pad need the have a hole for the exhaust and have to have a clamp down mechanism and equipment for fueling both stages. In contrast, the landing pad is supposed to be flat and clean. Take into account, that the fueled two-stage vehicle is extremely heavy. I cannot expect a floating pad to carry that weight. The launch pad must have legs to the bottom.

I did suggest a variant which accommodates this.

Alternate version:- separate launch and landing pads, each circulating. The vertical assembly tower would lift S1, landing pad would move away, launch pad would move in, S1 would be lowered and positioned, etc.

I agree re the legs. I would see legs built on the sea floor, and the launching pad positions and settles itself over these to make a stable launch platform.

BTW, I would expect the prop for the launch to be carried in tanks inside the pad barge. Possibly the subcooling infrastructure would be built into the launch site, and not required to be on the launch barges.

Cheers, Martin

I suggested something similar a few pages back. If the tanks in the launching platform are well insulated they could keep the propellants subcooled with little need for subcooling equipment on board.

I like the idea of a having a Floating Mobile Launcher Platform that is sent to a designated launching spot ~10 miles away from shore. That spot has underwater legs that reach a few meters under the surface, so that the FMLP can sit on top by lowering itself when it fills its tanks with water. There the rocket is fueled and launched, and the FMLP returns to the facility.

The first stage lands on a larger ASDS and is sent back either on top of the ASDS or on a specialized ship. The second stage lands on land, close to the FMLP facility, where it is prepared and mated to a first stage on a FMLP. The facility is next to the water and has a few hundred meters of canal under a roof. Adding FMLPs and first stage return ships can make this scale to support a very large launch rate. Also this can work anywhere, and does not have to be close to the BFR factory.
Title: Re: Where will BFR launch from?
Post by: Ludus on 07/03/2016 05:09 pm
We would need a bigger barge for the BFR's first stage if it's to conduct a barging. If it tried to land on OCISLY, it would crush the barge under its weight and sink it.
Umm, no it wouldn't. Those Marmacs have lifted things an order of magnitude heavier than an empty BFR stage.

Can a 52m wide ASDS have a large enough landing area for a 15m core? I suppose it might not have the same proportions so it might be stable without as wide a landing leg stance. By then they'd also be very confident about landing accuracy.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/03/2016 05:52 pm
We would need a bigger barge for the BFR's first stage if it's to conduct a barging. If it tried to land on OCISLY, it would crush the barge under its weight and sink it.
Umm, no it wouldn't. Those Marmacs have lifted things an order of magnitude heavier than an empty BFR stage.

Can a 52m wide ASDS have a large enough landing area for a 15m core? I suppose it might not have the same proportions so it might be stable without as wide a landing leg stance. By then they'd also be very confident about landing accuracy.
Right. The legs could be shorter provided the stage isn't much taller. So the footprint for BFR and F9R may be within a few meters.

I don't think SpaceX would shy away from a larger barge if they thought it might help, but neither do I think a significantly larger barge is strictly required.
Title: Re: Where will BFR launch from?
Post by: Lars-J on 07/04/2016 12:02 am
I just don't see SpaceX wanting to ever land a BFR 1st stage down range on a barge/drone ship.

They'll IMO take the performance hit to make it RTLS every time. It makes reuse much simpler and more cost effective.  And the landing pad will be very close to the launch pad.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/04/2016 01:05 am
I just don't see SpaceX wanting to ever land a BFR 1st stage down range on a barge/drone ship.

They'll IMO take the performance hit to make it RTLS every time. It makes reuse much simpler and more cost effective.  And the landing pad will be very close to the launch pad.
It could go either way.

A landing droneship that can refuel the BFR to fly back quickly (as Musk hinted at) or a BFR that's simply built larger to overcome the performance penalty of RTLS in the first place. Either one would work.
Title: Re: Where will BFR launch from?
Post by: wannamoonbase on 07/04/2016 04:22 am
Anyone that thinks the next SpaceX rocket after FH is a 15 meter, 15 million Lbf rocket is on some good stuff.
Yeah, it's called "known facts", but you'll have to wait for September 24 to take a hit from it.

SpaceX can state whatever they want, doesn't make it so.  The history of wildly inaccurate schedules tells us that.

There is going to need to be billions of dollars needed to make a BFR and this MCT thing happen. 

Where does it come from, a money tree, good intentions?

It's a great goal, but such a rocket is too much for the revenue generating market that is the current industry cash flow. 

Can it be built yes.  But I think there is at least 1, maybe 2 steps between Falcon rockets and a BFR.  I'll gladly be wrong, maybe we'll see in 10 years. 
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 07/04/2016 04:24 am
Anyone that thinks the next SpaceX rocket after FH is a 15 meter, 15 million Lbf rocket is on some good stuff.
Yeah, it's called "known facts", but you'll have to wait for September 24 to take a hit from it.

Somewhere there is goi g to need to be billions of dollars needed to make a BFR and Mars plan happen. 

Where does it come from? 

It's a great goal, but such a rocket is too much for the revenue generating market. 

Can it be built yes.  But I think there is at least 1, maybe 2 steps between Falcon rockets and a BFR.

And the next eight years will prove whether you are correct, or Elon Musk is...
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/04/2016 04:52 am
SpaceX is worth $10b and have already started paying for the engine. I believe they'll pay for MCT out of revenue in addition to what they can scrounge from DoD and/or NASA development contracts.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 07/04/2016 05:11 am
SpaceX is worth $10b and have already started paying for the engine. I believe they'll pay for MCT out of revenue in addition to what they can scrounge from DoD and/or NASA development contracts.

There are several threads throughout this forum about how SpaceX seems to believe they will be using their LEO internet constellation to generate a lot of the revenue needed for BFR/BFS development and construction.  And the Mars program itself is, I believe, designed to generate revenue through sales of passages to Mars once the colonization effort begins.  Not enough to cover a large percentage of the costs, but enough to contribute a needed share.

Again, a lot of the answers to these questions will come out this September... :)
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/04/2016 05:16 am
SpaceX is worth $10b and have already started paying for the engine. I believe they'll pay for MCT out of revenue in addition to what they can scrounge from DoD and/or NASA development contracts.

There are several threads throughout this forum about how SpaceX seems to believe they will be using their LEO internet constellation to generate a lot of the revenue needed for BFR/BFS development and construction.  And the Mars program itself is, I believe, designed to generate revenue through sales of passages to Mars once the colonization effort begins.  Not enough to cover a large percentage of the costs, but enough to contribute a needed share.

Again, a lot of the answers to these questions will come out this September... :)
To be clear, the LEO constellation is to pay for the Mars city, according to Musk. That may well include the BFR/MCT, but sounds much broader than just a launch vehicle.
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/04/2016 04:13 pm
Anyone that thinks the next SpaceX rocket after FH is a 15 meter, 15 million Lbf rocket is on some good stuff.
Yeah, it's called "known facts", but you'll have to wait for September 24 to take a hit from it.

SpaceX can state whatever they want, doesn't make it so.  The history of wildly inaccurate schedules tells us that.

There is going to need to be billions of dollars needed to make a BFR and this MCT thing happen. 

Where does it come from, a money tree, good intentions?

It's a great goal, but such a rocket is too much for the revenue generating market that is the current industry cash flow. 

Can it be built yes.  But I think there is at least 1, maybe 2 steps between Falcon rockets and a BFR.  I'll gladly be wrong, maybe we'll see in 10 years.

If you're referring to a Raptor-powered upper stage on Falcon 9/Falcon Heavy as one of those steps, then yes that pretty likely to happen before BFR.

Even if it costs 10x as much to develop BFR and a payload-carrying upper stage for it as Falcon, that's only 3.5 to 4 billion dollars. Thats a lot of money, but not that different than most EELV-class launcher families.
Title: Re: Where will BFR launch from?
Post by: mfck on 07/04/2016 09:35 pm
Anyone that thinks the next SpaceX rocket after FH is a 15 meter, 15 million Lbf rocket is on some good stuff.
Yeah, it's called "known facts", but you'll have to wait for September 24 to take a hit from it.

SpaceX can state whatever they want, doesn't make it so.  The history of wildly inaccurate schedules tells us that.


This is not about schedule, but about what size of LV/SC will be next. SX stated their intentions, which I referenced. You implied there will inevitably be intermediate (smaller) LV/SC. No schedule apart from next is involved and your appeal to prior history is irrelevant.

Quote

There is going to need to be billions of dollars needed to make a BFR and this MCT thing happen. 

Where does it come from, a money tree, good intentions?


Do you have insight into SX R&D costs? Any SX costs? 'Billions' is a range between roughly 2 and 999, you might want to sharpen your based on nothing assessment. Anyway, SpaceX is evaluated at over $10B right now, even before FH has ever flown or Crewed Dragon docked with ISS. Do you have any doubt Elon Musk is or will be able, over the next couple of years, to attract 'billions' of investment? Model 3 preorder week might have eluded your lunar-centric attention, but maybe Alphabet's equity purchase in SpaceX made it?

Have you ever heard the phrase "Shut up and take my money!"?

Quote

It's a great goal, but such a rocket is too much for the revenue generating market that is the current industry cash flow. 


EM showed time and again that "too much for the revenue generating market that is the current industry cash flow" (entertaining a thought that I understand what you meant by this phrase) is merely an "Enter Here" sign to him.

Quote

Can it be built yes.  But I think there is at least 1, maybe 2 steps between Falcon rockets and a BFR.  I'll gladly be wrong, maybe we'll see in 10 years.

We will see much sooner. In two years your assumption will have been proven wrong.
Title: Re: Where will BFR launch from?
Post by: Hyperion5 on 07/05/2016 01:53 am
Not so sure BFRs won't land downrange on a "droneship" {Barge REDACTED}.
Issue being a good fraction of a Km/sec used to negate and change the sign of the downrange velocity.  Payload penalty of a couple tens of tonnes.


The payload penalty for fully reusable RTLS launch is much higher than a few tens of tonnes.  Let's assume the BFR can launch 300 tonnes of vehicle and payload to LEO in an expendable flight.  If we only wanted to reuse the core stage with a barge launch, the payload penalty is as low as 2-4%.  So that's 12 tonnes of capacity gone.  To reuse the upper stage, you need about the same amount of propellant.  Factor in heat shielding and landing legs, and you're looking at around a 10% mass hit.  However since the rocket stage doesn't get any lighter, the hit to payload reaching is much higher than that.  If you want to RTLS the core, that's at least an additional 20% mass hit. Although the mass hit seems reasonable, the payload penalty is a severe 55%.  What that means is any heavy cargo launch cannot use RTLS launch. 
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/05/2016 02:33 am
Not so sure BFRs won't land downrange on a "droneship" {Barge REDACTED}.
Issue being a good fraction of a Km/sec used to negate and change the sign of the downrange velocity.  Payload penalty of a couple tens of tonnes.


The payload penalty for fully reusable RTLS launch is much higher than a few tens of tonnes.  Let's assume the BFR can launch 300 tonnes of vehicle and payload to LEO in an expendable flight.  If we only wanted to reuse the core stage with a barge launch, the payload penalty is as low as 2-4%.  So that's 12 tonnes of capacity gone.  To reuse the upper stage, you need about the same amount of propellant.  Factor in heat shielding and landing legs, and you're looking at around a 10% mass hit.  However since the rocket stage doesn't get any lighter, the hit to payload reaching is much higher than that.  If you want to RTLS the core, that's at least an additional 20% mass hit. Although the mass hit seems reasonable, the payload penalty is a severe 55%.  What that means is any heavy cargo launch cannot use RTLS launch.

Evaluating these trade-offs requires understanding the paradigm BFR is proposed under: BFR is never going to be launched intentionally expendable, so quoting payload reduction relative to expendable is really irrelevant. BFR will forgo maximum capacity for easy relaunch.

Musk said the hit for Falcon 9 doing RTLS is 40% and barge landing is 30% reduction compared to expendable Falcon 9. Squeezing that extra 10% out of Falcon 9 is entirely worthwhile since it helps them compete with Ariane in GTO launches. BFR will have no competition except itself, at least for a while. So why would it need to land down-range?

Either: A) it can't loft a fully-loaded MCT to a parking orbit and still RTLS, or B) there's some other payload that HAS to be launched all in one shot. In case A), that would be incredibly poor foresight in design, when making it 10% bigger would allow much easier processing. In case B), what is that payload? No currently proposed commercial payloads will use even 150 tonnes, never mind 200. Fuel can be launched in as many shots as necessary: it doesn't really matter in this paradigm whether it takes 8 launches or 9 to refuel a couple of MCT/BFS in LEO, but it does matter a lot if it takes several days (instead of minutes) to get a booster back into the HIF.

Getting back to where BFR will launch from: eventually, it will have to support a healthy launch rate, meaning flyback for rapid processing. That indicates to me a semi-submersible platform with onboard landing pad and integration facilities. Similar to Sea Launch Odyssey but on a larger scale.
Title: Re: Where will BFR launch from?
Post by: GORDAP on 07/05/2016 11:29 pm
Not so sure BFRs won't land downrange on a "droneship" {Barge REDACTED}.
Issue being a good fraction of a Km/sec used to negate and change the sign of the downrange velocity.  Payload penalty of a couple tens of tonnes.


The payload penalty for fully reusable RTLS launch is much higher than a few tens of tonnes.  Let's assume the BFR can launch 300 tonnes of vehicle and payload to LEO in an expendable flight.  If we only wanted to reuse the core stage with a barge launch, the payload penalty is as low as 2-4%.  So that's 12 tonnes of capacity gone.  To reuse the upper stage, you need about the same amount of propellant.  Factor in heat shielding and landing legs, and you're looking at around a 10% mass hit.  However since the rocket stage doesn't get any lighter, the hit to payload reaching is much higher than that.  If you want to RTLS the core, that's at least an additional 20% mass hit. Although the mass hit seems reasonable, the payload penalty is a severe 55%.  What that means is any heavy cargo launch cannot use RTLS launch. 

Hyperion, rather than evaluating the payload penalty for barge landing versus RTLS, could you state how much larger the BFR would have to be to perform RTLS versus barge landing, with the same payload?  I think this is how SpaceX will evaluate this decision - compare the cost savings of RTLS (versus barge) against the delta cost of designing/operating a significantly larger BFR.
Title: Re: Where will BFR launch from?
Post by: pobermanns on 07/06/2016 09:56 pm
Anyone that thinks the next SpaceX rocket after FH is a 15 meter, 15 million Lbf rocket is on some good stuff.
Yeah, it's called "known facts", but you'll have to wait for September 24 to take a hit from it.

Somewhere there is goi g to need to be billions of dollars needed to make a BFR and Mars plan happen. 

Where does it come from? 

It's a great goal, but such a rocket is too much for the revenue generating market. 

Can it be built yes.  But I think there is at least 1, maybe 2 steps between Falcon rockets and a BFR.

And the next eight years will prove whether you are correct, or Elon Musk is...

Maybe I'm totally F.O.S., but I have this sense that EM has harnessed a latent dream for exploration. He has a following which believes in his vision. True believers.

When I listen to him speak, he sounds like he has some sort of disability, with his halting speech, but nonetheless, the results of his efforts are amazing. How long has he been in the space business - 12 years? And despite being a "new kid on the block", he has created a business model that is causing older launch providers (ULA) to have to layoff workers due to the competition. How does he do this?

I've been to business school - got an MBA to my name -  and I spent 20 years in the Navy as an officer, but I have a hard time understanding how he motivates his guys and gals to bust their a***s to make this work. In my day, I never could motivate people like he does. And motivation is the pivotal ingredient. When you can harness the energies of a couple thousand true-bellevers, you can make things happen. Beats me how he does it, though.

How will he assemble the hardware and infrastructure to accomplish this? No clue, but I believe that he will succeed.
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 07/06/2016 11:06 pm
Anyone that thinks the next SpaceX rocket after FH is a 15 meter, 15 million Lbf rocket is on some good stuff.
Yeah, it's called "known facts", but you'll have to wait for September 24 to take a hit from it.

Somewhere there is goi g to need to be billions of dollars needed to make a BFR and Mars plan happen. 

Where does it come from? 

It's a great goal, but such a rocket is too much for the revenue generating market. 

Can it be built yes.  But I think there is at least 1, maybe 2 steps between Falcon rockets and a BFR.

And the next eight years will prove whether you are correct, or Elon Musk is...

Maybe I'm totally F.O.S., but I have this sense that EM has harnessed a latent dream for exploration. He has a following which believes in his vision. True believers.

When I listen to him speak, he sounds like he has some sort of disability, with his halting speech, but nonetheless, the results of his efforts are amazing. How long has he been in the space business - 12 years? And despite being a "new kid on the block", he has created a business model that is causing older launch providers (ULA) to have to layoff workers due to the competition. How does he do this?

I've been to business school - got an MBA to my name -  and I spent 20 years in the Navy as an officer, but I have a hard time understanding how he motivates his guys and gals to bust their a***s to make this work. In my day, I never could motivate people like he does. And motivation is the pivotal ingredient. When you can harness the energies of a couple thousand true-bellevers, you can make things happen. Beats me how he does it, though.

How will he assemble the hardware and infrastructure to accomplish this? No clue, but I believe that he will succeed.

I believe this is the same phenomenon we saw in the '60s with the people who worked on Apollo.  They would work 60, 70, 80 hour weeks, not see their families for weeks at a time, sometimes leave their paychecks uncashed in their desk drawers...

Because they were working on something not only historic, but resonant with the very heart of the human soul -- they were working on sending people to the Moon.

Well, Elon Musk is working to send people to Mars.  Again, not only historic, but resonant with the human spirit of exploration.  And of working towards a goal that is so much bigger than any one of the SpaceX employees who are happily working at less than industry standard, and working 60, 70, 80 hours a week...

Put a person in the position to shoot for the stars, and she/he will work harder, and more selflessly, in pursuit of a Great Goal.

And there are so few Great Goals out there, that anyone is even daring to accomplish.  That anyone even admits is accomplishable.  That anyone is doing despite everyone else saying "You'll never be able to pay for it!"

Doesn't matter what Everyone Else is saying -- Musk is going ahead and shooting for it.

That's what is motivating his people.  It's not Musk himself, I don't think.  It's the goal.  The Great Goal.

Great Goals are seductive...
Title: Re: Where will BFR launch from?
Post by: Hyperion5 on 07/07/2016 12:49 am
Not so sure BFRs won't land downrange on a "droneship" {Barge REDACTED}.
Issue being a good fraction of a Km/sec used to negate and change the sign of the downrange velocity.  Payload penalty of a couple tens of tonnes.


The payload penalty for fully reusable RTLS launch is much higher than a few tens of tonnes.  Let's assume the BFR can launch 300 tonnes of vehicle and payload to LEO in an expendable flight.  If we only wanted to reuse the core stage with a barge launch, the payload penalty is as low as 2-4%.  So that's 12 tonnes of capacity gone.  To reuse the upper stage, you need about the same amount of propellant.  Factor in heat shielding and landing legs, and you're looking at around a 10% mass hit.  However since the rocket stage doesn't get any lighter, the hit to payload reaching is much higher than that.  If you want to RTLS the core, that's at least an additional 20% mass hit. Although the mass hit seems reasonable, the payload penalty is a severe 55%.  What that means is any heavy cargo launch cannot use RTLS launch.

Evaluating these trade-offs requires understanding the paradigm BFR is proposed under: BFR is never going to be launched intentionally expendable, so quoting payload reduction relative to expendable is really irrelevant. BFR will forgo maximum capacity for easy relaunch.

Musk said the hit for Falcon 9 doing RTLS is 40% and barge landing is 30% reduction compared to expendable Falcon 9. Squeezing that extra 10% out of Falcon 9 is entirely worthwhile since it helps them compete with Ariane in GTO launches. BFR will have no competition except itself, at least for a while. So why would it need to land down-range?

On the contrary, you just quoted the payload reduction relative to expendable launch, thus demonstrating exactly why I did it earlier.  Quoting the payload reduction from expendable launch provides us with a good universal reference in evaluating various methods of reuse against one another.  As for why you need to land the BFR core down-range, it needs to land down-range or else the BFS won't even be able to get 100 tonnes of cargo into orbit (not counting its own mass).  There is supporting work in the L2 Spacex section's Simulation thread should you have access.  Also worth noting is the fact that the Falcon 9 is only partly reusable, which is why the BFR has a higher payload reduction with RTLS (although its barge landing payload reduction is small relative to the F9). 

Either: A) it can't loft a fully-loaded MCT to a parking orbit and still RTLS, or B) there's some other payload that HAS to be launched all in one shot. In case A), that would be incredibly poor foresight in design, when making it 10% bigger would allow much easier processing. In case B), what is that payload? No currently proposed commercial payloads will use even 150 tonnes, never mind 200. Fuel can be launched in as many shots as necessary: it doesn't really matter in this paradigm whether it takes 8 launches or 9 to refuel a couple of MCT/BFS in LEO, but it does matter a lot if it takes several days (instead of minutes) to get a booster back into the HIF.

Case A is NOT a case of incredibly poor foresight.  This thread is about where the BFR will launch from, which in turn is heavily affected by the size of the BFR.  If Spacex can get away with a much smaller rocket lifting the same payload via barge launch, it makes a whole host of things cheaper and easier, especially selecting & building a launch site.  You save money on other things as well, including the rocket's design, engine design, tooling, production costs, fuel costs (you need less), maintenance (smaller equals cheaper), and it's even easier to move the rocket around.  With the current BFR figures we're aware of, you could use an upgraded KSC pad with a barge launch and still get a 100 tonne payload into orbit.  If you only consider RTLS there's no way the rocket required would be able to launch from those pads. 

With regards to Case B, there are several 100-tonne plus payloads required.  My work with Lamontagne suggests that a fully-manned BFS will require that amount for the crew, their supplies & their living quarters (especially that last part).  In addition to that, tanker flights & heavy cargo flights would also require an astronomical amount of mass lift.  It's also not practical to transfer multiple tonnes of cargo from one RTLS-launched BFS to another in orbit.  It takes weeks to move just a few tonnes from a Dragon to the ISS.  Imagine multiplying that problem by 20X.  I'm also dubious that any launch site, even a ship-based one, could handle a launch more than every couple of days.  Politically that would also make selecting KSC as a launch site rather hard and that would subject the launch site to incredible wear and tear.  How many Floridians are going to put up with a rocket twice the size of a Saturn V launching every day from KSC? 

Getting back to where BFR will launch from: eventually, it will have to support a healthy launch rate, meaning flyback for rapid processing. That indicates to me a semi-submersible platform with onboard landing pad and integration facilities. Similar to Sea Launch Odyssey but on a larger scale.

That is going to be one massive ship, which if anything happens to the BFR during launch, will also prove incredibly time-consuming & costly to replace.  Launching from KSC or Puerto Rico at least lets you spread your assets around and avoid a RUD wiping out all of your launch & flight preparation facilities in one shot. 
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/07/2016 03:07 pm
I compared expendable to reusable for Falcon, which IS still a frequently fully expended launcher. BFR won't be, so it's expendable payload is about as relevant as the Shuttle's. Musk said Falcon 9 FT can put 18-20t IMLEO with S1 RTLS, and he also said that BFR will have ~8x F9FT thrust, implying ~160-180t IMLEO with S1 RTLS. Yes, a lot of that will be upper stage return mass, but 100t payload and RTLS aren't necessarily mutually exclusive in a 15 mlbf rocket. Launching less than 100t to allow RTLS is not a long-term solution, though it might happen if they expect Raptor improvements down the road.

I'm not sure it's much easier to site a launch facility for a 12 mlbf rocket than it is a 15 mlbf rocket. Any of the pads at KSC would have to be almost entirely rebuilt to handle that, and it's not like daily launches of a rocket 1.5x the size of the Saturn V is going to be any more acceptable to locals than daily launches of a rocket 2x the size of the Saturn V. A huge frigging rocket launch is still huge even if it's 15% smaller, so I highly doubt they will do daily BFR launches from land anywhere, nevermind optimize for daily launches from land.

Launching monthly (on average) from new/rebuilt pads at KSC and Boca Chica would be sufficient until they are sending more than 10 MCTs to Mars per synod. Even optimistically, that's going to be at least 15 years from now. Realistically, I'd say at least 20 years... considering that they won't even send the first one for at least 8 years and probably 10-12 years.

By the time they get to daily launches, a 5-day barge return would be a major operational constraint. There are ways to speed that up: land on a fast ship; transfer to a fast ship; land on a suborbital launch capable pad and fly back to the main pad. But all of those are also major operational headaches. And yes, a floating pad/integration facility would be very large, although not absurdly so by ship standards. Building and maintaining multiple dedicated on-shore launch facilities is extremely expensive also, and much more limited by geographical and environmental concerns - and is not really less susceptible to an on-pad explosion.

Basically, we already know BFR is going to be too big for current pads and flying monthly at most for the near term. There's no point in sizing it for daily launches on current ranges when that flight rate is 15-20 years down the road and most likely from offshore. And in reality, SpaceX will do whatever optimizes cost per 100t delivered to the Mars surface... which might turn out to be barge landing.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/07/2016 03:29 pm
Falcon 9 is not a fully expended rocket. They've recovered the cores and at least one of their recovered cores they intend to launch. That makes it not a fully expended rocket.

Perhaps you could make the claim they haven't proven it's reusable in-flight, and I'll grant that, but you can't say it's a fully expended rocket when they have 3-4 cores which have flown but haven't been expended.
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/07/2016 03:49 pm
Falcon 9 is not a fully expended rocket. They've recovered the cores and at least one of their recovered cores they intend to launch. That makes it not a fully expended rocket.

Perhaps you could make the claim they haven't proven it's reusable in-flight, and I'll grant that, but you can't say it's a fully expended rocket when they have 3-4 cores which have flown but haven't been expended.

F9 is operated and priced like a fully expendable rocket, and will continue to be at least until it's reflown and the price for reflight drops. It's also frequently fully expended (albeit experimentally), and can optionally be flown intentionally fully expendable.

BFR will be none of the above, because there's no rational business case to fly BFR like F9. BFR has to fly with at least the booster fully reuseable, or it will never fly at all.
Title: Re: Where will BFR launch from?
Post by: Lobo on 07/07/2016 04:00 pm
Falcon 9 is not a fully expended rocket. They've recovered the cores and at least one of their recovered cores they intend to launch. That makes it not a fully expended rocket.

Perhaps you could make the claim they haven't proven it's reusable in-flight, and I'll grant that, but you can't say it's a fully expended rocket when they have 3-4 cores which have flown but haven't been expended.

I think it's fair to say that F9 was originally designed to be a standard expendable rocket.  The booster was later modified so that it could land and be reused, but that wasn't part of it 's original concept.  At least I don't think it was.

In MCT they would be designing it from the start for reuse, and things like road transportability won't be design criteria like it was for F9.  So, it could end up being more "efficient" at reusability than F9, with less mass penalty for reuse than F9.



Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/07/2016 05:01 pm
Falcon 9 is not a fully expended rocket. They've recovered the cores and at least one of their recovered cores they intend to launch. That makes it not a fully expended rocket.

Perhaps you could make the claim they haven't proven it's reusable in-flight, and I'll grant that, but you can't say it's a fully expended rocket when they have 3-4 cores which have flown but haven't been expended.

F9 is operated and priced like a fully expendable rocket, and will continue to be at least until it's reflown and the price for reflight drops. It's also frequently fully expended (albeit experimentally), and can optionally be flown intentionally fully expendable.

BFR will be none of the above, because there's no rational business case to fly BFR like F9. BFR has to fly with at least the booster fully reuseable, or it will never fly at all.
You called F9 fully expended, which is a false statement as I showed. Just be like "sure, yeah, whatever." ;)
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/07/2016 05:16 pm
Falcon 9 is not a fully expended rocket. They've recovered the cores and at least one of their recovered cores they intend to launch. That makes it not a fully expended rocket.

Perhaps you could make the claim they haven't proven it's reusable in-flight, and I'll grant that, but you can't say it's a fully expended rocket when they have 3-4 cores which have flown but haven't been expended.

F9 is operated and priced like a fully expendable rocket, and will continue to be at least until it's reflown and the price for reflight drops. It's also frequently fully expended (albeit experimentally), and can optionally be flown intentionally fully expendable.

BFR will be none of the above, because there's no rational business case to fly BFR like F9. BFR has to fly with at least the booster fully reuseable, or it will never fly at all.
You called F9 fully expended, which is a false statement as I showed. Just be like "sure, yeah, whatever." ;)

It's a completely semantic point in the context of this discussion. But fixed, just for you :)
Title: Re: Where will BFR launch from?
Post by: Nomadd on 07/07/2016 05:23 pm
Falcon 9 is not a fully expended rocket. They've recovered the cores and at least one of their recovered cores they intend to launch. That makes it not a fully expended rocket.

Perhaps you could make the claim they haven't proven it's reusable in-flight, and I'll grant that, but you can't say it's a fully expended rocket when they have 3-4 cores which have flown but haven't been expended.

I think it's fair to say that F9 was originally designed to be a standard expendable rocket.  The booster was later modified so that it could land and be reused, but that wasn't part of it 's original concept.  At least I don't think it was.

In MCT they would be designing it from the start for reuse, and things like road transportability won't be design criteria like it was for F9.  So, it could end up being more "efficient" at reusability than F9, with less mass penalty for reuse than F9.




That's not only not fair, it's completely wrong. The Merlin and F9 were designed to be reusable from the start. Designers and engineers have been commenting on how much harder it was to make everything reusable from day one. You don't just modify things like turbopumps made for a single flight to last for 50. They have to be designed and built that way from the beginning.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/07/2016 05:36 pm
The entire design of v1.1 was built around VTVL reusability from the start. People have this idea that VTVL reuse was just an afterthought for Falcon 9, that it was just "strapped on" to an expendable rocket, and that's plain false. Falcon 9 was almost totally redesigned around VTVL reuse from v1.0 (designed for parachute reuse) to v1.1.
Title: Re: Where will BFR launch from?
Post by: guckyfan on 07/07/2016 05:38 pm
That's not only not fair, it's completely wrong. The Merlin and F9 were designed to be reusable from the start. Designers and engineers have been commenting on how much harder it was to make everything reusable from day one. You don't just modify things like turbopumps made for a single flight to last for 50. They have to be designed and built that way from the beginning.

IMO the most glaring fact that points to reusability from the beginning is the ratio between first and second stage. The second stage is designed to do much of the total work to get to orbit. The first stage stages early. So early by design, that it is easy to land. Other launch vehicles have their first stages go much faster at MECO.
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/07/2016 05:57 pm
Falcon 9 is not a fully expended rocket. They've recovered the cores and at least one of their recovered cores they intend to launch. That makes it not a fully expended rocket.

Perhaps you could make the claim they haven't proven it's reusable in-flight, and I'll grant that, but you can't say it's a fully expended rocket when they have 3-4 cores which have flown but haven't been expended.

I think it's fair to say that F9 was originally designed to be a standard expendable rocket.  The booster was later modified so that it could land and be reused, but that wasn't part of it 's original concept.  At least I don't think it was.

In MCT they would be designing it from the start for reuse, and things like road transportability won't be design criteria like it was for F9.  So, it could end up being more "efficient" at reusability than F9, with less mass penalty for reuse than F9.
That's not only not fair, it's completely wrong. The Merlin and F9 were designed to be reusable from the start. Designers and engineers have been commenting on how much harder it was to make everything reusable from day one. You don't just modify things like turbopumps made for a single flight to last for 50. They have to be designed and built that way from the beginning.

And not only last for 50 flights, but cheap enough to throw away after 1 flight if necessary. That's the REALLY hard part. Designing something to be NON-expendable is different than designing to be reusable... and it affects a lot of other architecture elements, including overall size and thus launch location.
Title: Re: Where will BFR launch from?
Post by: RedLineTrain on 07/07/2016 07:31 pm
I think it's fair to say that F9 was originally designed to be a standard expendable rocket.  The booster was later modified so that it could land and be reused, but that wasn't part of it 's original concept.  At least I don't think it was.

Quote from: Musk quoted in 2008 article
"If people do anything that contributes to this [rocket] stage not being recoverable," Elon says at one point, "they will find their work undone"

http://www.gq.com/story/elon-musk-paypal-solar-power-electric-cars-space-travel
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/07/2016 08:20 pm
Even Falcon 1 first stage and some of the earlier Falcon 9 upper stages (in addition to all the first stages) were designed to allow eventual reuse. They attempted parachute recovery of Falcon 1 AND Falcon 9 first stages. They were trying to do this from day 1. And certainly everything first stage from Merlin 1C and on was focused on reuse capability.
Title: Re: Where will BFR launch from?
Post by: Ludus on 07/07/2016 09:50 pm
The entire design of v1.1 was built around VTVL reusability from the start. People have this idea that VTVL reuse was just an afterthought for Falcon 9, that it was just "strapped on" to an expendable rocket, and that's plain false. Falcon 9 was almost totally redesigned around VTVL reuse from v1.0 (designed for parachute reuse) to v1.1.

This is why Ariane and ULA Vulcan go with what seem like exotic and far off "too little too late" architectures for reusability despite the apparent success of SpaceX. They can't just strap it on. They can't emulate what SpaceX is doing without completely junking what they've got  and starting over from scratch.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/07/2016 09:59 pm
Ludus: Indeed.

Crucially, you can't use a rocket that just has one or two engines for VTVL for an orbital stage (i.e. very good mass ratio) unless you add auxilliary rockets or accept a VERY low staging velocity (i.e. see Blue Origin's New Shepard), which kind of defeats the purpose of a reusable first stage, since now your expendable upper stage must now do almost all the delta-v (though with some benefits).

SpaceX kind of lucked out that the original parachute-recovery Falcon 9 v1.0 had 9 engines and so they could use roughly the same kind of setup for the VTVL-optimized Falcon 9 v1.1. Blue Origin, which is taking a similar approach, has shown about 6-7 engines on their reusable orbital booster concept images, which fits with the physics of optimal VTVL reusable boosters.
Title: Re: Where will BFR launch from?
Post by: Lobo on 07/07/2016 10:25 pm
Falcon 9 is not a fully expended rocket. They've recovered the cores and at least one of their recovered cores they intend to launch. That makes it not a fully expended rocket.

Perhaps you could make the claim they haven't proven it's reusable in-flight, and I'll grant that, but you can't say it's a fully expended rocket when they have 3-4 cores which have flown but haven't been expended.

I think it's fair to say that F9 was originally designed to be a standard expendable rocket.  The booster was later modified so that it could land and be reused, but that wasn't part of it 's original concept.  At least I don't think it was.

In MCT they would be designing it from the start for reuse, and things like road transportability won't be design criteria like it was for F9.  So, it could end up being more "efficient" at reusability than F9, with less mass penalty for reuse than F9.




That's not only not fair, it's completely wrong. The Merlin and F9 were designed to be reusable from the start. Designers and engineers have been commenting on how much harder it was to make everything reusable from day one. You don't just modify things like turbopumps made for a single flight to last for 50. They have to be designed and built that way from the beginning.

Hmmm...

Interesting.  I don't recall there being any discussion about reusability or flyback and landing the booster during the original run up to F9 v1.0.  I seem to remember price points that were discussed being based on the economics of scale, not reusability.  I don't recall that coming along until later after F9 v1.0 was flying or about to fly. 
And obviously F9 1.0 was -not- reusable right from the start (as MCT would be).  It took the major upgrades of v1.1 for that.  They seemed to be pretty focused on just getting an EELV class LV successfully flying in an expendable mode there at first.  If boost back and landing was the goal right from the start, seems the v1.0 core would have looked more like the first v1.1 cores.  No legs attached, but designed to have them installed later once the core was flight proven.

In fact, early SpaceX concepts for the future involved Upgrading the 9 Merlin 1 engine cluster for a single Merlin 2.  How would they fly back and land the booster with such a massive single engine?  So while Merlin 1 may have been designed to be able to be reused, I still don't think flying back and reusing the F9 booster was the original plan when they designed the v1.0.  It seems perhaps to be a later thought, when someone put together than a 9 engine cluster and an engine capable of being reused actually had an advantage in having the capability of lower thrust for boosting back and landing that a single massive engine wouldn't have.


Title: Re: Where will BFR launch from?
Post by: wannamoonbase on 07/07/2016 10:51 pm
That's not only not fair, it's completely wrong. The Merlin and F9 were designed to be reusable from the start. Designers and engineers have been commenting on how much harder it was to make everything reusable from day one. You don't just modify things like turbopumps made for a single flight to last for 50. They have to be designed and built that way from the beginning.

IMO the most glaring fact that points to reusability from the beginning is the ratio between first and second stage. The second stage is designed to do much of the total work to get to orbit. The first stage stages early. So early by design, that it is easy to land. Other launch vehicles have their first stages go much faster at MECO.


So you're saying they need a third stage 😜 And recover the second stage on a ASDS off the coast of Africa?

As for the cartoonish size and near SciFi capabilities of the BFR and the MCT, don't be too disappointed if in 20 years you're wondering where it went.

I'm still waiting for the NASP, X33, X34, Beal Aerospace, Roton to make their first flights. 

SpaceX can do impressive things, but changing the laws of physics or rocket equation are not on the list.  Reality is a harsh border. 

Edit: Daily BFR and 10 MCT flights. That was almost too much.  The flight attendant almost ended up wearing my drink.   This is not thought out. 
Title: Re: Where will BFR launch from?
Post by: Lobo on 07/07/2016 11:06 pm
That's not only not fair, it's completely wrong. The Merlin and F9 were designed to be reusable from the start. Designers and engineers have been commenting on how much harder it was to make everything reusable from day one. You don't just modify things like turbopumps made for a single flight to last for 50. They have to be designed and built that way from the beginning.

IMO the most glaring fact that points to reusability from the beginning is the ratio between first and second stage. The second stage is designed to do much of the total work to get to orbit. The first stage stages early. So early by design, that it is easy to land. Other launch vehicles have their first stages go much faster at MECO.

Not sure about that Gucky.  I think perhaps the fuel and ISP of the engines may have more been the driver in that.  Kerolox GG engines.  Delta 4 and Atlas V have higher efficiency hydrolox or staged combustion engines, and so could burn their cores longer because the performance doesn't fall off like solid or GG kerolox does.  (plus they use relatively low thrust upper stage engines in single RL-10's...especially in their heavier variants, so if they stage too early, there could be gravity loss issues)
Reuse wasn't really a factor in the design of the S-1C and S-1B stages, and they had stages that staged more comparable (although a little sooner) to F9 v1.0.  They both had high thrust 2nd stages, so they could.  F9 has a relatively high thrust 2nd stage too.

If reuse was the driver from the start (at least the boost back and propulsive landing type of reuse), wouldn't they probably go the other way?  Have the booster stage even sooner, so it's not going as fast and not as far down range at staging?  And make the upper stage larger in ratio?  A little more expended aluminum alloy tankage and up powering the Merlin-vac (if necessary) in the 2nd stage seems like a pretty minor cost to get your booster back as easy as possible?
Seems that'd make getting the booster back easier than it is now.  All that speed and distance down range that helps you get the 2nd stage and payload going, now works against you to recover. 

But as always, I could be wrong.  :-)

Title: Re: Where will BFR launch from?
Post by: Lobo on 07/07/2016 11:20 pm
I think it's fair to say that F9 was originally designed to be a standard expendable rocket.  The booster was later modified so that it could land and be reused, but that wasn't part of it 's original concept.  At least I don't think it was.

Quote from: Musk quoted in 2008 article
"If people do anything that contributes to this [rocket] stage not being recoverable," Elon says at one point, "they will find their work undone"

http://www.gq.com/story/elon-musk-paypal-solar-power-electric-cars-space-travel

Ahh, thanks for that RedLine,

That was back in 2008 during the ramp up to the first F9 v1.0 launch.  I didn't recall discussion about reusability until after, so thanks for sharing this.

Although, their original plans for a Merlin 2 (in 2010) would seem to contradict at least a propulsive landing  type of recovery, because it wouldn't be capable of that.  So perhaps the original plan was some sort of parachute Recovery as RobotBeat mentioned instead?

Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/08/2016 01:21 am
Yeah, they tried parachute recovery with Falcon 9, though they didn't publicize it much.

Funny story, I recently got banned from the Facebook SpaceX fan page because I insisted (correctly, I might add) that SpaceX attempted recovery before v1.1, and specifically with Falcon 9 and the guy who I was arguing against was the Admin (which I wasn't aware of at the time). I didn't respond fast enough, so he banned and blocked me, so I wasn't able to show him I was actually correct. (Stupid reason to ban someone even if I had been wrong, but hey, there you go... He blocked me as soon as he banned me, so I had no way to contact him.)

There's even a picture in SpaceX's old News archives of guys training in SCUBA outfits and a pontoon designed for floating the Falcon 9 booster stage out of the water. And of course, SpaceX added cork on the outside of the Falcon 9 in an attempt to prevent the first stage from over-heating and rupturing during the belly-flop of atmospheric reentry. And SpaceX sent out a recovery boat as well and had room for parachutes in the stage and everything.

It's all in this forum, for those who are around.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/08/2016 01:23 am
I think it's fair to say that F9 was originally designed to be a standard expendable rocket.  The booster was later modified so that it could land and be reused, but that wasn't part of it 's original concept.  At least I don't think it was.

Quote from: Musk quoted in 2008 article
"If people do anything that contributes to this [rocket] stage not being recoverable," Elon says at one point, "they will find their work undone"

http://www.gq.com/story/elon-musk-paypal-solar-power-electric-cars-space-travel

Ahh, thanks for that RedLine,

That was back in 2008 during the ramp up to the first F9 v1.0 launch.  I didn't recall discussion about reusability until after, so thanks for sharing this.

Although, their original plans for a Merlin 2 (in 2010) would seem to contradict at least a propulsive landing  type of recovery, because it wouldn't be capable of that.  So perhaps the original plan was some sort of parachute Recovery as RobotBeat mentioned instead?
Just to add to what I was saying, Jon Goff will tell you that they were originally quite confident in their parachute splashdown recovery and kind of scoffed at propulsive landing recovery until they found out parachute recovery didn't work and then Elon saw and was hugely impressed by Masten Space Systems' work.

So yeah, it most certainly wasn't SpaceX's original plan to go for VTVL. But they WERE shooting for reuse from as soon as they were launching rockets.
Title: Re: Where will BFR launch from?
Post by: rst on 07/08/2016 01:24 am
Although, their original plans for a Merlin 2 (in 2010) would seem to contradict at least a propulsive landing  type of recovery, because it wouldn't be capable of that.  So perhaps the original plan was some sort of parachute Recovery as RobotBeat mentioned instead?

Parachutes were indeed the plan, and the first two F9 v1.0 stages launched with them. This was discussed with the press at the time, though they mention it less since switching strategies.

See, e.g., https://www.newscientist.com/blogs/shortsharpscience/2011/09/falcon-rockets-to-land-on-thei.html?DCMP=OTC-rss&nsref=online-news
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/08/2016 01:30 am
Although, their original plans for a Merlin 2 (in 2010) would seem to contradict at least a propulsive landing  type of recovery, because it wouldn't be capable of that.  So perhaps the original plan was some sort of parachute Recovery as RobotBeat mentioned instead?

Parachutes were indeed the plan, and the first two F9 v1.0 stages launched with them. This was discussed with the press at the time, though they mention it less since switching strategies.

See, e.g., https://www.newscientist.com/blogs/shortsharpscience/2011/09/falcon-rockets-to-land-on-thei.html?DCMP=OTC-rss&nsref=online-news
Ah, thanks for finding a good reference. Can someone let the Admin of the SpaceX Facebook fan page know so I can be reinstated?
Title: Re: Where will BFR launch from?
Post by: Ludus on 07/08/2016 05:34 pm
Although, their original plans for a Merlin 2 (in 2010) would seem to contradict at least a propulsive landing  type of recovery, because it wouldn't be capable of that.  So perhaps the original plan was some sort of parachute Recovery as RobotBeat mentioned instead?

Parachutes were indeed the plan, and the first two F9 v1.0 stages launched with them. This was discussed with the press at the time, though they mention it less since switching strategies.

See, e.g., https://www.newscientist.com/blogs/shortsharpscience/2011/09/falcon-rockets-to-land-on-thei.html?DCMP=OTC-rss&nsref=online-news
Ah, thanks for finding a good reference. Can someone let the Admin of the SpaceX Facebook fan page know so I can be reinstated?

You were right. I think that helps to understand Elon's path to success to get that he's often wrong about the details. He doesn't have miraculous insight into what's going to work. He really does reason from first principles though about what needs to be done and what's possible.
Title: Re: Where will BFR launch from?
Post by: BobHk on 07/08/2016 10:23 pm
Ludus: Indeed.

Crucially, you can't use a rocket that just has one or two engines for VTVL for an orbital stage (i.e. very good mass ratio) unless you add auxilliary rockets or accept a VERY low staging velocity (i.e. see Blue Origin's New Shepard), which kind of defeats the purpose of a reusable first stage, since now your expendable upper stage must now do almost all the delta-v (though with some benefits).

SpaceX kind of lucked out that the original parachute-recovery Falcon 9 v1.0 had 9 engines and so they could use roughly the same kind of setup for the VTVL-optimized Falcon 9 v1.1. Blue Origin, which is taking a similar approach, has shown about 6-7 engines on their reusable orbital booster concept images, which fits with the physics of optimal VTVL reusable boosters.

Have you considered that New Shepherd might be their second stage...

Thats rough that you got banned for that admins ignorance.

Are there any images of their chute recovery?
Title: Re: Where will BFR launch from?
Post by: Lobo on 07/08/2016 11:22 pm
Although, their original plans for a Merlin 2 (in 2010) would seem to contradict at least a propulsive landing  type of recovery, because it wouldn't be capable of that.  So perhaps the original plan was some sort of parachute Recovery as RobotBeat mentioned instead?

Parachutes were indeed the plan, and the first two F9 v1.0 stages launched with them. This was discussed with the press at the time, though they mention it less since switching strategies.

See, e.g., https://www.newscientist.com/blogs/shortsharpscience/2011/09/falcon-rockets-to-land-on-thei.html?DCMP=OTC-rss&nsref=online-news
Ah, thanks for finding a good reference. Can someone let the Admin of the SpaceX Facebook fan page know so I can be reinstated?

No Facebook for you!

;-)
Title: Re: Where will BFR launch from?
Post by: Lobo on 07/08/2016 11:41 pm
Although, their original plans for a Merlin 2 (in 2010) would seem to contradict at least a propulsive landing  type of recovery, because it wouldn't be capable of that.  So perhaps the original plan was some sort of parachute Recovery as RobotBeat mentioned instead?

Parachutes were indeed the plan, and the first two F9 v1.0 stages launched with them. This was discussed with the press at the time, though they mention it less since switching strategies.

See, e.g., https://www.newscientist.com/blogs/shortsharpscience/2011/09/falcon-rockets-to-land-on-thei.html?DCMP=OTC-rss&nsref=online-news
Ah, thanks for finding a good reference. Can someone let the Admin of the SpaceX Facebook fan page know so I can be reinstated?

Yes thanks!

That ties together a few loose ends, like the proposed Merlin 2.  If they were parachute recovering, then having a single large engine would be fine.  Seems like the switch to propulsive landing was perhaps a merger of two things, parachuting not working quite as originally thought, and the -upside- to having a large cluster of small engines is that you can fire a small number of them to do low-thrust maneuvers.  Like boost-back and propulsive landing.  :-)
Then, that "detriment" of having a large cluster of small Falcon-1 booster engines, is actually a positive because it gives a lot of propulsive flexibility.  So no need for a new single engine, what they had was actually going to work out better.

Interesting, and always good to learn new things.  :-)

Ok, so let me elaborate on my earlier misspeak.  When I said that I didn't think that F9 v1.0 was designed from the start for reuse, I mean specifically that it wasn't designed for the type of propulsive landing they went to later.  It took a pretty major upgrade of F9 in order to do that.  Had that been the plan from the start, I would think v1.0 would have all the attachment points for the legs and provisions for adding cold gas thrusters as v1.1 did.  Not to mention the Merlin 2 Concept.
Of course, I didn't know they had been looking to do parachute recovery, so I just said in general it wasn't designed for reuse.
And even v1.1, IMO, was more adding VTVL capability to an existing launcher, and not a clean sheet design.  So there would be compromises and inefficiencies.   
So, a clean sheet design like MCT, designed from the very inception with Falcon 9 like booster recovery could be more efficient at it than F9 is, because it's a clean sheet design and will integrate everything they've learned with F9 into it....as well as a lot of new things as well.
It may have lower penalties for boost back, and even RTLS landing, depending on it's design and launch profile. 

So that was actually my point in my original post on the previous page.  But it got sidetracked by my generalization about reuse not being part of v1.0 design.  My bad.  :-)
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/09/2016 12:49 am
Ludus: Indeed.

Crucially, you can't use a rocket that just has one or two engines for VTVL for an orbital stage (i.e. very good mass ratio) unless you add auxilliary rockets or accept a VERY low staging velocity (i.e. see Blue Origin's New Shepard), which kind of defeats the purpose of a reusable first stage, since now your expendable upper stage must now do almost all the delta-v (though with some benefits).

SpaceX kind of lucked out that the original parachute-recovery Falcon 9 v1.0 had 9 engines and so they could use roughly the same kind of setup for the VTVL-optimized Falcon 9 v1.1. Blue Origin, which is taking a similar approach, has shown about 6-7 engines on their reusable orbital booster concept images, which fits with the physics of optimal VTVL reusable boosters.

Have you considered that New Shepherd might be their second stage...

Thats rough that you got banned for that admins ignorance.

Are there any images of their chute recovery?
(Facebook is kind of a waste of time, so may be for the best anyway... And I apologize to everyone for bringing up that off-topic personal thing.)

Hard to find, as SpaceX did not publicize the recovery attempts of Falcon 9 as much as they mentioned it for Falcon 1.
Title: Re: Where will BFR launch from?
Post by: pobermanns on 07/10/2016 10:44 pm
That's not only not fair, it's completely wrong. The Merlin and F9 were designed to be reusable from the start. Designers and engineers have been commenting on how much harder it was to make everything reusable from day one. You don't just modify things like turbopumps made for a single flight to last for 50. They have to be designed and built that way from the beginning.

IMO the most glaring fact that points to reusability from the beginning is the ratio between first and second stage. The second stage is designed to do much of the total work to get to orbit. The first stage stages early. So early by design, that it is easy to land. Other launch vehicles have their first stages go much faster at MECO.

Not sure about that Gucky.  I think perhaps the fuel and ISP of the engines may have more been the driver in that.  Kerolox GG engines.  Delta 4 and Atlas V have higher efficiency hydrolox or staged combustion engines, and so could burn their cores longer because the performance doesn't fall off like solid or GG kerolox does.  (plus they use relatively low thrust upper stage engines in single RL-10's...especially in their heavier variants, so if they stage too early, there could be gravity loss issues)
Reuse wasn't really a factor in the design of the S-1C and S-1B stages, and they had stages that staged more comparable (although a little sooner) to F9 v1.0.  They both had high thrust 2nd stages, so they could.  F9 has a relatively high thrust 2nd stage too.

If reuse was the driver from the start (at least the boost back and propulsive landing type of reuse), wouldn't they probably go the other way?  Have the booster stage even sooner, so it's not going as fast and not as far down range at staging?  And make the upper stage larger in ratio?  A little more expended aluminum alloy tankage and up powering the Merlin-vac (if necessary) in the 2nd stage seems like a pretty minor cost to get your booster back as easy as possible?
Seems that'd make getting the booster back easier than it is now.  All that speed and distance down range that helps you get the 2nd stage and payload going, now works against you to recover. 

But as always, I could be wrong.  :-)

And indeed, you certainly could be. Were you in attendance at the board meetings at SpaceX when they discussed reusability? No? Darn!

Many other members - much more experienced than I am - have commented on the incremental path that SpX has been following. In that path, my opinion is that they have been prudent while open to improvements which would allow more aggressive operations. Seems pretty sensible to me. Probably reusability was a dream from the onset, and the sucesses prompted them to push on to grander goals. WRT to the timing of staging, I expect that, if they had it all to do over again, they woulcl change things  like you suggest. But, they are in full-experimental mode  - see what works, then expand from that. It is unfair to require them to have had an Übersicht for their whole operation.
Title: Re: Where will BFR launch from?
Post by: guckyfan on 07/11/2016 06:06 am
The Falcon 9 design had to work well both expendable and reusable and it does. I think for BFR/BFS their optimization will go that direction, chose a steep trajectory, let the first stage eat mostly the gravity losses, stage early for easy RTLS and let the second stage do most of the work of getting to orbital speed. Inefficient when expendable, but a good compromise for reusability, particularly for RTLS.

I know not everybody agrees on RTLS but I think they will go that way and optimize the whole design for it with lessons learned from Falcon 9.
Title: Re: Where will BFR launch from?
Post by: oldAtlas_Eguy on 07/11/2016 06:42 pm
RTLS as a design requirement means the pad area has to have enough space for the BFR to both launch and then land. Now also at not to far a distance the assembly/refurbishment/manufacturing plant and you need quite a lot of real estate.
Title: Re: Where will BFR launch from?
Post by: pobermanns on 07/11/2016 06:43 pm
The Falcon 9 design had to work well both expendable and reusable and it does. I think for BFR/BFS their optimization will go that direction, chose a steep trajectory, let the first stage eat mostly the gravity losses, stage early for easy RTLS and let the second stage do most of the work of getting to orbital speed. Inefficient when expendable, but a good compromise for reusability, particularly for RTLS.

I know not everybody agrees on RTLS but I think they will go that way and optimize the whole design for it with lessons learned from Falcon 9.
Good points. Mostly makes sense to me.

And don't forget, they're the first ones to try reusability. Like any engineering project, there will be lots of pros and cons to trade off with each other, and eventually better combinations become apparent. I don't know if RTLS has been a prime directive for them - vs. landing on a droneship - but you may be right.

Or, maybe EM should have read this book at the beginning.
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/11/2016 07:23 pm
RTLS as a design requirement means the pad area has to have enough space for the BFR to both launch and then land. Now also at not to far a distance the assembly/refurbishment/manufacturing plant and you need quite a lot of real estate.

Depends on what "refurbishment" means. If they can get several (5? 10?) flights with just inspections and maybe minor maintenance, then refurbishment could be done at some distance from the pad. For example, manufacture, and refurbish in Brownsville (or somewhere else with barge access), but integrate, inspect, maintain, launch and land at Boca Chica and LC-39/LZ-1
Title: Re: Where will BFR launch from?
Post by: Lobo on 07/11/2016 10:18 pm
The Falcon 9 design had to work well both expendable and reusable and it does. I think for BFR/BFS their optimization will go that direction, chose a steep trajectory, let the first stage eat mostly the gravity losses, stage early for easy RTLS and let the second stage do most of the work of getting to orbital speed. Inefficient when expendable, but a good compromise for reusability, particularly for RTLS.

Yup, exactly the point I was originally trying for, I just did it in a bit of a clumsy way.  ;-)

I know not everybody agrees on RTLS but I think they will go that way and optimize the whole design for it with lessons learned from Falcon 9.

Yes, this is a voice that keeps speaking in my head (which could be the whole problem!  heh)

I worked with Hyperion on the MCT design team, and I don't doubt the numbers he and Dimitri have come up with.  And we've talked about it on a few occasions.  But it seems like they keep assuming a Falcon 9-like ascent profile.  Which I think is more optimized for ELV, since they weren't planning to try propulsive recover of the booster originally.  (back to my original point) It was designed to stage at optimum times for the power and efficiency of the engines and mass and type of fuel, as well as being road transportable, etc. etc. 
But MCT will be designed from the start for propulsive landing.  And there's things you can do to help mitigate the penalties for booster recovery that weren't part of F9's design. 

Is it possible to factor all of that in and create a RHLV that can get the required mass to LEO and have the booster be RTLS?  We'll all have to wait to see...I can't say.   But I think they're at least trying very hard for it because it greatly simplifies operations and logistics.  Especially for a future robust flight rate.  It's nice not to have to wait for barges to go down range, and come back, or even need barge access at all (if the stages are built on site, and then can  return to that site to land) or deal with the various sea and weather conditions at the recovery zone which can scrub launches. 

I guess I look at it like this.  Theoretically, the booster could have a lofted enough ascent profile that it wouldn't need to do any boostback.  It'd be like SpaceShipOne and Two.  It'd just go up and down again.  And a little down range, and the rotation of the Earth will move the launch site right back under the descent trajectory.  This is probably too steep, but I'm just using it as an example.  This means the upper stage has to do a lot of the ascent, and would need big tanks and a lot of thrust.  But if MCT is integrated on the upper stage and is coming back from the surface Mars to Earth on one tank of fuel, it'll already need big tanks and a lot of thrust by default.  You can't make it too small optimized for Earth ascent, since it needs to get itself back. (Unless there's some other LMO refueling infrastructure MCT will have that we don't know about yet).  Even if MCT has a dedicated reusable 2nd stage that just inserts the spacecraft into LEO, it could still be made large enough to do this if they wanted.
So you could have a powerful booster but with relatively small tanks to break the gravity loss and gain altitude.  Then a large upperstage/spacecraft that will take it from there to LEO for refueling.  Perhaps something like STS, where the ET was essentially a very large ground-lit upper stage.  This would be air-lit after boost phase, but it's just for analogy purposes.  It wasn't the most efficient ascent profile for a ELV, but it wasn't designed to be an ELV. 
And as long as the booster gets the spacecraft/upperstage just into vacuum, it's vacuum engines will be much more efficient than sea level Raptors trying to push the stack in a vacuum.  So there can be some efficiency gain there, as long as there's sufficient thrust to overcome the gravity losses at "low and slow" staging.

But Hyperion and Dimitri are both way smarter than me, so I don't put enough stock in my gut feeling and speculation to do anything more than say IMO they're likely at least trying to figure out if there's any possible way they can build RTLS into MCT's design.  :-)

Title: Re: Where will BFR launch from?
Post by: Lobo on 07/11/2016 10:20 pm

And indeed, you certainly could be. Were you in attendance at the board meetings at SpaceX when they discussed reusability? No? Darn!

Sorry, I had schedule conflicts and was unable to attend those board meetings.  ;-)


Many other members - much more experienced than I am - have commented on the incremental path that SpX has been following. In that path, my opinion is that they have been prudent while open to improvements which would allow more aggressive operations. Seems pretty sensible to me. Probably reusability was a dream from the onset, and the sucesses prompted them to push on to grander goals. WRT to the timing of staging, I expect that, if they had it all to do over again, they woulcl change things  like you suggest. But, they are in full-experimental mode  - see what works, then expand from that. It is unfair to require them to have had an Übersicht for their whole operation.

Yup, I agree fully with this.  :-)
Title: Re: Where will BFR launch from?
Post by: Stan-1967 on 07/11/2016 10:42 pm
The Falcon 9 design had to work well both expendable and reusable and it does. I think for BFR/BFS their optimization will go that direction, chose a steep trajectory, let the first stage eat mostly the gravity losses, stage early for easy RTLS and let the second stage do most of the work of getting to orbital speed. Inefficient when expendable, but a good compromise for reusability, particularly for RTLS.

Yup, exactly the point I was originally trying for, I just did it in a bit of a clumsy way.  ;-)

I know not everybody agrees on RTLS but I think they will go that way and optimize the whole design for it with lessons learned from Falcon 9.


But it seems like they keep assuming a Falcon 9-like ascent profile.  Which I think is more optimized for ELV, since they weren't planning to try propulsive recover of the booster originally.  (back to my original point) It was designed to stage at optimum times for the power and efficiency of the engines and mass and type of fuel, as well as being road transportable, etc. etc. 
 

I guess I look at it like this.  Theoretically, the booster could have a lofted enough ascent profile that it wouldn't need to do any boostback.  It'd be like SpaceShipOne and Two.  It'd just go up and down again.  And a little down range, and the rotation of the Earth will move the launch site right back under the descent trajectory....



And as long as the booster gets the spacecraft/upperstage just into vacuum, it's vacuum engines will be much more efficient than sea level Raptors trying to push the stack in a vacuum.  .....

It sounds like you have just described a BFR modeled on a "New Shepard" type of flight profile.  Is there thinking at SpaceX suggesting that path, while less technically impressive that DPL or a flyback RTLS, is it a better solution for re-use?

Blue Origin seems to be much further along to "gas & go" on the vehicle than SpaceX.  I wonder if that a demonstration of foresight of the BO team?  If so, perhaps Blue Origin is more on technical par with SpaceX if you look at barge landings as a dead end for reuse.
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/12/2016 12:42 am
...
This means the upper stage has to do a lot of the ascent, and would need big tanks and a lot of thrust.  But if MCT is integrated on the upper stage and is coming back from the surface Mars to Earth on one tank of fuel, it'll already need big tanks and a lot of thrust by default. 
...
So you could have a powerful booster but with relatively small tanks to break the gravity loss and gain altitude.  Then a large upperstage/spacecraft that will take it from there to LEO for refueling.
...

The Falcon 9 upper stage is already pretty large and stages quite low. Staging to LEO is probably going to be the most demanding leg of the trip, so I don't know if it will be oversized for that, since it would be way oversized for the other legs.
Title: Re: Where will BFR launch from?
Post by: JamesH65 on 07/12/2016 08:32 am
It sounds like you have just described a BFR modeled on a "New Shepard" type of flight profile.  Is there thinking at SpaceX suggesting that path, while less technically impressive that DPL or a flyback RTLS, is it a better solution for re-use?

Blue Origin seems to be much further along to "gas & go" on the vehicle than SpaceX.  I wonder if that a demonstration of foresight of the BO team?  If so, perhaps Blue Origin is more on technical par with SpaceX if you look at barge landings as a dead end for reuse.

BO's dev path is different - they have gone down the small, suborbital, check out G&G route, move to orbital. SpaceX have gone another way, get to orbit first, then incrementally move to G&G.

So not directly comparable - they are taking different routes to the same goal.

Will be interesting to see how the timescales match up when they converge to similar capabilities.
Title: Re: Where will BFR launch from?
Post by: Lobo on 07/12/2016 04:14 pm
...
This means the upper stage has to do a lot of the ascent, and would need big tanks and a lot of thrust.  But if MCT is integrated on the upper stage and is coming back from the surface Mars to Earth on one tank of fuel, it'll already need big tanks and a lot of thrust by default. 
...
So you could have a powerful booster but with relatively small tanks to break the gravity loss and gain altitude.  Then a large upperstage/spacecraft that will take it from there to LEO for refueling.
...

The Falcon 9 upper stage is already pretty large and stages quite low. Staging to LEO is probably going to be the most demanding leg of the trip, so I don't know if it will be oversized for that, since it would be way oversized for the other legs.

It stages low and slow compared to some ELV's like Delta IV and Atlas V.  But it stages higher and faster than the Shuttle SRB's did, than the Titan SRB's did, and than the S-1B and S-1C GG kerolox stages did, as well as the Soyuz kerolox GG boosters.

I'm just saying if optimizing for propulsive landing of the booster...especially if trying to recover it at the launch site...it would be easier if the booster phase was more like these really low and slow boosters, rather than more like current EELV's.

In that case, I picture it on the pad looking closer to the booster to upper stage ratio of Saturn 1B or Saturn INT-21, than to Falcon 9. 

And when considering both stages have the same propellant unlike Saturn 1B, the ratio could be more similar to Saturn 1B but stage the booster even sooner than Saturn 1B did and the upper stage do even more than the S-IVB did.  More like SRB boost profiles, but a little more lofted ascent.  Almost like a "booster assisted SSTO", if you will.  MCT would be SSTO when taking off from Mars anyway.  Actually "Single Stage to TEI".  So it really should just need -some- extra help with Earth's deeper gravity well to get itself to LEO...it's not even going all the way to TMI like it is when it's coming back.
The Spacecraft will have to be quite a capable single stage vehicle in it's own right.  Just needs some JATO-like assist to get off Earth's runway with a full load...so to speak.  And it may be able to take it from there itself.

I actually picture such a stack looking quite like this Saturn 1B with PLF sitting on the pad, ironically enough.







Title: Re: Where will BFR launch from?
Post by: envy887 on 07/12/2016 04:57 pm
Yes, I think BFR will loft more and stage slower than Falcon, to help with RTLS.

But it will still have to do SOME boostback. I think you're overestimating the dV for both TEI and do boostback, and underestimating the dV to get to LEO. LEO is over 6 km/s from where F9 stages, and BFS has to do that leg with over 100t of payload. BFS will single-stage to TEI, but only with about 25t of payload and that's only 6.5 to 7 km/s from Mars surface.

Once it's big enough to put 100t through 6 km/s, making BFS bigger is not optimal. Put the same mass into the booster and do a boost-back burn. Boostback is only pushing the dry mass of the booster, so it takes very little fuel to get incredible dV. And the ISP difference in vacuum between the engines is only 4% (363 vs 380) so you're saving very little by deferring that dry mass to the upper stage, at the cost of sending that mass to Mars and back.

Title: Re: Where will BFR launch from?
Post by: Lobo on 07/12/2016 05:54 pm
Yes, I think BFR will loft more and stage slower than Falcon, to help with RTLS.

But it will still have to do SOME boostback. I think you're overestimating the dV for both TEI and do boostback, and underestimating the dV to get to LEO. LEO is over 6 km/s from where F9 stages, and BFS has to do that leg with over 100t of payload. BFS will single-stage to TEI, but only with about 25t of payload and that's only 6.5 to 7 km/s from Mars surface.

Once it's big enough to put 100t through 6 km/s, making BFS bigger is not optimal. Put the same mass into the booster and do a boost-back burn. Boostback is only pushing the dry mass of the booster, so it takes very little fuel to get incredible dV. And the ISP difference in vacuum between the engines is only 4% (363 vs 380) so you're saving very little by deferring that dry mass to the upper stage, at the cost of sending that mass to Mars and back.

Yes, valid points.

Once they've factored in enough dV to get the ship plus X-mass (25mt?) from the surface of Mars back to Earth, then that's really the long pole task the spacecraft will have to do all by itself, as you say.  Then one would assume they'd design to booster to provide all the additional necessary dV to get 100mt from the surface of the Earth to LEO.  That plus whatever is required for boostback (barge or RTLS) will be what determines booster size and design.
That's the scenario that Hyperion and Dimitry used to determine that RTLS won't be possible.  So trying to speculate on -some- way SpaceX might be able to make it possible, by possibly oversizing the tanks of BFS for Earth ascent.  As I think we can all agree RTLS is preferable if at all possible.

A little larger propellant tanks really don't add much mass to a stage/ship, by themselves.  So there could be some trade off there if doing so would allow booster RTLS, and not doing so means a barge landing is necessary.  So not making BFS mass optimal, but possibly optimal for logistics/operations if it tipped the scale to allow for RTLS, as long as it could still perform it's other functions, -could- be a way SpaceX could try to get RTLS.  (Hypothetical speculation, of course.) 
And although adding some more tankage to BFS may not add much mass itself, if that extra tankage also requires other things like additional reinforcing structure, TPS or possibly an additional engine for sufficient thrust at early staging, then in totality the additional mass could be too great to do.



Title: Re: Where will BFR launch from?
Post by: philw1776 on 07/12/2016 08:13 pm
Yes, I think BFR will loft more and stage slower than Falcon, to help with RTLS.

But it will still have to do SOME boostback. I think you're overestimating the dV for both TEI and do boostback, and underestimating the dV to get to LEO. LEO is over 6 km/s from where F9 stages, and BFS has to do that leg with over 100t of payload. BFS will single-stage to TEI, but only with about 25t of payload and that's only 6.5 to 7 km/s from Mars surface.

Once it's big enough to put 100t through 6 km/s, making BFS bigger is not optimal. Put the same mass into the booster and do a boost-back burn. Boostback is only pushing the dry mass of the booster, so it takes very little fuel to get incredible dV. And the ISP difference in vacuum between the engines is only 4% (363 vs 380) so you're saving very little by deferring that dry mass to the upper stage, at the cost of sending that mass to Mars and back.

Agree with these parameters so I took another cut at BFR/BFS with a heavy 100mT BFS and in attached spreadsheet a lighter 85mT with a look to RTLS.  Attached spreadsheet much easier to read.
Mid 20s # engines stage one, 5 Rvacs stage 2.  Stage 2 the BFS does the Km/sec work having been boosted to altitude and just a couple Km/sec by the BFR which heads home for rapid refurb and re-flight.  Upon reflection if Elon is consistent with his minimize cost mantra, the craft needs to RTLS.

   BFR & BFS MODELS: MCT as 2nd Stage with 100  Metric Tons CARGO      
      BLUE: Enter parameter variable   
Mars MCT Freight to Earth   25   Elon "1/4 payload return to Earth" +25mT landing propellant   
S1 Avg ISP Sea L to MECO   335      
S2 vac ISP   380      
Raptor sea level thrust KLB & mT   518   235   Elon "over 230mT"
Rvac thrust KLB & mT   642   291   Rvac Thrust same 124% ratio as with F9 FT+
Propellant Density   1.06   mT/m3   3.7:1   O2 to CH4
         
BFR DIA   15.0   m                                                   1. Enter BFR Rocket DIA
MCT BFS Dry Wt & Cargo   200   mT   metric tonnes   2. Enter BFS Total Mass
S2 Dry Mass   100   mT   
Propellant for S2 BFS Landing   20   mT   
Mass to LEO   220   mT   
1st Stage Propellant Tank Length   16.5   m                    3. Enter S1 Propellant Tank length
S1 Propellant Volume   2914   m3   volume drives S1 mass & DeltaV
Propellant Mass   3089   mT   (real tanks much longer, just computing vol)
S1 Dry Wt %    4.5%                                                4. Enter Dry Wt %
S1 DRY Weight   146   mT   
S1 Total Weight mT   3235   mT   
S! Dry Wt Delta V (No 2nd stage)   10.2   Km/sec Rocket Equation   
Stage One Full Load Delta V    3.08   Km/sec Rocket Equation   
RTxx Propellant   315   mT                                              5. Propellant boostbk, re-entry, land
RTxx Delta V @Minimum Load   3.78   Km/sec Rocket Equation   Return To Launch Site RTLS
Est S1 Gravity Loss    0.8   Km/sec                               6. est to get S1 Vel @ Burnout
Est S1 Velocity @ Burnout   2.28   Km/sec   Elon 8,000 Km/Hr (2.2 Km/s)
2nd Stage Propellant Tank Length   6.0   m               7. Enter 2nd stage Tank length
Propellant Volume   1,060   m3   drives S2 BFS mass & Delta V
Propellant Mass   1,123   mT   (real tanks much longer, just computing vol)
S2 Mass w/MCT   1,323   mT   
S2 Mass w/MCT   2.9   Million LBS   
Calc # Rvac Raptor Eng   4.95      1.09                            8. Enter T/W to get # S2 engines
# Rvac Raptor Eng   5      (starting T/W <1 ok as still 'falling up')
Stage 2 Thrust mT   1457      
Stage 2 Thrust   3.2   Million LBS   
Stage 2 Km/sec    6.68   Km/sec Rocket Equation   need >6.5 Km/sec LEO to Mars landing
Stage 2 Drt Wt %   8.2%      
S1 + S2  Total Delta V Capability   9.0   Km/sec    ~< 9 Km/sec to LEO w/grav loss
S2 Mars Return XXmT Cargo   8.6   Km/sec Rocket Equation    >8Km/sec return Mars surf to Earth
TOTAL WT mT   4,558   mT   
TOTAL WT LBS   10.0   Million LBS   
THRUST Needed LBS force   13.4   Million LBS   
THRUST Needed mT   6062   mT   
THRUST Needed MegaNewtons   59   MegaNewtons   
1st Stage T/W @ Takeoff   1.33                                  9. Enter >1.2 to get # S1 engines  (Old F9 T/W=1.19)   
# ENG Not Rounded Up   25.8      
1st STAGE # ENG    26      
LEO Mass Fract   4.8%    %   
LEO Wet to Dry Mass Ratio   21    F9 v1.1 25/1 Musk   http://exoscientist.blogspot.com/2013/11/the-coming-sstos-falcon-9-v11-first.html
MCT Cargo Hold length  swag   10   m   
MCT Cargo Vol m3   1766   m3   
   Eng 16+8+2=26      
   Outer Ring, Inner Ring, Central Engs      
NOTE 1:   S1 Km/sec + S2 Km/sec must ~< 9Km/sec for LEO with grav losses      
NOTE 2:   Rocket Equation      http://www.quantumg.net/rocketeq.html
NOTE 3:    LEO esc 3.2Km/s + Fast transit ~1.5 Km/s + aerocapture + Mars brake & landing 1.8Km/s = 6.5 Km/sec Delta V for 2nd stage MCT      
NOTE 4:    Mars Return with reduced freight must be ~ 8Km/sec  Since propellant capacity exceeds this, won't fully refuel on Mars      

Title: Re: Where will BFR launch from?
Post by: darkenfast on 07/14/2016 05:22 am
https://forum.nasaspaceflight.com/index.php?topic=35425.msg1559579#msg1559579

Over on the Texas Launch Site thread, Jim says he doesn't think the MCT will launch from Boca Chica because of safety reasons and notes the size of the exclusion zone around the Saturn V launches. 
Title: Re: Where will BFR launch from?
Post by: hkultala on 07/14/2016 06:09 am
The Falcon 9 design had to work well both expendable and reusable and it does. I think for BFR/BFS their optimization will go that direction, chose a steep trajectory, let the first stage eat mostly the gravity losses, stage early for easy RTLS and let the second stage do most of the work of getting to orbital speed. Inefficient when expendable, but a good compromise for reusability, particularly for RTLS.

Yup, exactly the point I was originally trying for, I just did it in a bit of a clumsy way.  ;-)

I know not everybody agrees on RTLS but I think they will go that way and optimize the whole design for it with lessons learned from Falcon 9.

Yes, this is a voice that keeps speaking in my head (which could be the whole problem!  heh)

I worked with Hyperion on the MCT design team, and I don't doubt the numbers he and Dimitri have come up with.  And we've talked about it on a few occasions.  But it seems like they keep assuming a Falcon 9-like ascent profile.  Which I think is more optimized for ELV, since they weren't planning to try propulsive recover of the booster originally.

There is no single "F9 ascent profile".

There are about four different styles of F9 ascent profiles, even for same destination orbit:

1) Original 1.0 ascent profile
2) Expendable 1.1 ascent profile (second stage lenghtened much more than first stage, stages considerably earlier)
3) Barge landing 1.1/FT ascent profile
4) RTLS ascent profile.

So when they were making the 1.1 version, they already considered the reusing of first stage and increased the size of the second stage considereably because of that.

Title: Re: Where will BFR launch from?
Post by: BobHk on 07/14/2016 05:11 pm
https://forum.nasaspaceflight.com/index.php?topic=35425.msg1559579#msg1559579

Over on the Texas Launch Site thread, Jim says he doesn't think the MCT will launch from Boca Chica because of safety reasons and notes the size of the exclusion zone around the Saturn V launches.

Ask yourself where are you going to get the LNG/Methane for all those Mars launches if not south Texas?  With any site named please indicate the proximity of cheap ergtons of LNG nearby, thanks.
Title: Re: Where will BFR launch from?
Post by: Lobo on 07/14/2016 05:16 pm

There is no single "F9 ascent profile".

There are about four different styles of F9 ascent profiles, even for same destination orbit:

1) Original 1.0 ascent profile
2) Expendable 1.1 ascent profile (second stage lenghtened much more than first stage, stages considerably earlier)
3) Barge landing 1.1/FT ascent profile
4) RTLS ascent profile.

So when they were making the 1.1 version, they already considered the reusing of first stage and increased the size of the second stage considereably because of that.

Very good clarification.
I'm speaking more generally of F9 still has a more EELV like ascent profile.  It still has a large booster compared to it's upper stage, more like EELV's do.    It's booster is still moving pretty fast and is pretty far down range at staging.  Which is why it still has a pretty big penalty for RTLS.  (Although the upper stage stretch and Merlin 1-vac upgrades do help with that)

A clean sheet design would likely shorten and loft the booster ascent profile more, to mitigate that penalty for easier RTLS.  And either have a reusable upper stage, or a sufficiently powerful/economical expendable upper stage to make up the dV from the shorter boost phase.
If that was possible with the F9 hardware, F9-FT would probably be able to launch most typical GTO payloads and still be able to RTLS rather than still need barge landings.  Because isn't that the butter-zone for the commercial launch industry?  But if you are dancing with the girl that brought you, you have to work within it's limits.  And F9-FT seems to be about the best they can do with that.
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/14/2016 05:44 pm
https://forum.nasaspaceflight.com/index.php?topic=35425.msg1559579#msg1559579

Over on the Texas Launch Site thread, Jim says he doesn't think the MCT will launch from Boca Chica because of safety reasons and notes the size of the exclusion zone around the Saturn V launches.

Ask yourself where are you going to get the LNG/Methane for all those Mars launches if not south Texas?  With any site named please indicate the proximity of cheap ergtons of LNG nearby, thanks.
Any major city in the US has access to super cheap natural gas (super cheap in this context). And just like oxygen, SpaceX can liquify it themselves.
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/14/2016 07:04 pm
...
A clean sheet design would likely shorten and loft the booster ascent profile more, to mitigate that penalty for easier RTLS.  And either have a reusable upper stage, or a sufficiently powerful/economical expendable upper stage to make up the dV from the shorter boost phase.
...

These are two different design optima that suggest having different vehicles: a lander capable of transporting crew and cargo to the surface of Mars and back, and a large but light (and not expendable) upper stage that can launch extremely large LEO payloads, do direct GSO insertions, and most importantly launch all the fuel a Mars mission in less than 3 shots while still doing RTLS.

The BFS could stage at 2100 m/s but at only 900 tonnes with 4 Raptors, giving BFR more overhead for RTLS.
The Tanker could stage at 1400 m/s but mass 1600 tonnes with 6 RVacs, and the lower/slower staging point would allow the same BFR booster to lift the heavier stack and still RTLS. By my numbers (see attached spreadsheet) both should be under 12 mlbf at liftoff.
Title: Re: Where will BFR launch from?
Post by: envy887 on 07/15/2016 01:10 am
BFR will have much more propellant (if any of the speculation is close to correct) with greater destructive potential than F9 or FH.  Minimums assume it goes boom on the pad, and why minimums for guided and unguided are the same, and why those minimums increase with increasing vehicle size; FTS or no FTS.

That is why it is applicable and why BFR may not be allowed to launch from places F9 and FH launches are allowed.
...
Note that analysis of the debris impact area, distant focused overpressure (DFO), reasonably accurate expected casualty calculations (among other things) are difficult to impossible based on public information.

BFR will be 3 to 4 times bigger than FH according to both Musk and Shotwell, and methane is less energetic than LH2/LOX which in turn is roughly 40% more energetic than RP-1/LOX. Even assuming methalox and hydrolox are equivalent, the worst case BFR explosion will be less than 5.6 times more energetic than Falcon Heavy.

However, most energy dissipation phenomena fall off with the cube of radius from the energetic event; for those effects BFR only needs 1.75 times the standoff distance, and more likely 1.5 times, compared to Falcon Heavy.

Can anyone point out a debris impact, DFO, expected casualty, or other similar analysis for a launch vehicle, preferably a large one? Is this information available from Shuttle or DIVH launches?
Title: Re: Where will BFR launch from?
Post by: BobHk on 07/15/2016 11:09 pm
https://forum.nasaspaceflight.com/index.php?topic=35425.msg1559579#msg1559579

Over on the Texas Launch Site thread, Jim says he doesn't think the MCT will launch from Boca Chica because of safety reasons and notes the size of the exclusion zone around the Saturn V launches.

Ask yourself where are you going to get the LNG/Methane for all those Mars launches if not south Texas?  With any site named please indicate the proximity of cheap ergtons of LNG nearby, thanks.
Any major city in the US has access to super cheap natural gas (super cheap in this context). And just like oxygen, SpaceX can liquify it themselves.

Access is NOT the same as, hey its right over there.  You also need to X out any MAJOR CITY right?  No BFR launches from near New York or are you considering launching from just anywhere?
Title: Re: Where will BFR launch from?
Post by: philw1776 on 07/15/2016 11:23 pm
IMO, wiping out NY is a feature, not a bug.
(sports rival)
Title: Re: Where will BFR launch from?
Post by: Robotbeat on 07/16/2016 01:43 am
https://forum.nasaspaceflight.com/index.php?topic=35425.msg1559579#msg1559579

Over on the Texas Launch Site thread, Jim says he doesn't think the MCT will launch from Boca Chica because of safety reasons and notes the size of the exclusion zone around the Saturn V launches.

Ask yourself where are you going to get the LNG/Methane for all those Mars launches if not south Texas?  With any site named please indicate the proximity of cheap ergtons of LNG nearby, thanks.
Any major city in the US has access to super cheap natural gas (super cheap in this context). And just like oxygen, SpaceX can liquify it themselves.

Access is NOT the same as, hey its right over there.  You also need to X out any MAJOR CITY right?  No BFR launches from near New York or are you considering launching from just anywhere?
Only North Carolina (and a few states far north)  doesn't have natural gas pipelines on its coast.

There may be other reasons to prefer Texas over other places in the continental US, but none of them are "natural gas isn't available elsewhere."
Title: Re: Where will BFR launch from?
Post by: BobHk on 07/25/2016 02:39 am
https://forum.nasaspaceflight.com/index.php?topic=35425.msg1559579#msg1559579

Over on the Texas Launch Site thread, Jim says he doesn't think the MCT will launch from Boca Chica because of safety reasons and notes the size of the exclusion zone around the Saturn V launches.

Ask yourself where are you going to get the LNG/Methane for all those Mars launches if not south Texas?  With any site named please indicate the proximity of cheap ergtons of LNG nearby, thanks.
Any major city in the US has access to super cheap natural gas (super cheap in this context). And just like oxygen, SpaceX can liquify it themselves.

Access is NOT the same as, hey its right over there.  You also need to X out any MAJOR CITY right?  No BFR launches from near New York or are you considering launching from just anywhere?
Only North Carolina (and a few states far north)  doesn't have natural gas pipelines on its coast.

There may be other reasons to prefer Texas over other places in the continental US, but none of them are "natural gas isn't available elsewhere."

I look forward to the BFR/MCT FAA application for anywhere west of Texas' coast and north of the southermost tips of Florida or Texas.  If only for practical (its BFR not a bottlerocket) reasons: travel over a populated area without nearby splash space in an ocean.  Just how nervous is the FAA/will the FAA be of a BFR/MCT splashing down into open land in the western US?

What is the FAA's comfort zone?  I suspect its over an ocean.


Title: Re: Where will BFR launch from?
Post by: envy887 on 07/25/2016 02:53 am
30 casualties per million flights is the FAA expected casualty limit. Basically, it will have to be airliner-reliable before flying over anywhere populated, including the Western US.
Title: Re: Where will BFR launch from?
Post by: Ludus on 09/27/2016 09:24 pm
Florida, specifically LC39A.

It's the only thing that makes sense.

Consider NASA and DOD payloads, as they will be the big dollar clients.

I think the BFR structure and it's integration should be done at CCAFS as well.

Elon agrees.  :)
Title: Re: Where will BFR launch from?
Post by: the_other_Doug on 09/27/2016 10:41 pm
Elon did not say that LC-39A will be the only launch complex from which the ITS will fly, just that this is where they will fly it from at first.

I still believe, especially with the implied launch cadence, that there will be multiple launch sites, and that we ought not rule out Boca Chica for ITS launch operations at this point...
Title: Re: Where will BFR launch from?
Post by: yokem55 on 09/27/2016 10:55 pm
So what improvements to the 39A flame trench will be needed to allow 28 million pounds of thrust off that pad?  :o ??? :-\

Does SpaceX think that the 11 million pounds limit is too conservative?
Title: Re: Where will BFR launch from?
Post by: Toast on 09/27/2016 10:55 pm
I still believe, especially with the implied launch cadence, that there will be multiple launch sites, and that we ought not rule out Boca Chica for ITS launch operations at this point...

He did actually mention eventually launching it from the coast of Texas (obviously a reference to Boca Chica) during his speech.
Title: Re: Where will BFR launch from?
Post by: Lar on 09/28/2016 04:33 pm
See also http://forum.nasaspaceflight.com/index.php?topic=41292  ("Launching the ITS Rocket") (there may be a merge or rename, discussion underway)
Title: Re: Where will BFR launch from?
Post by: Chris Bergin on 09/28/2016 09:26 pm
ITS as a realignment! ;D

New thread for this subject:
http://forum.nasaspaceflight.com/index.php?topic=41303.0

Locked.