Author Topic: SpaceX Cape 39A Starship launch/landing facilities  (Read 388303 times)

Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #20 on: 07/06/2019 02:14 pm »
Where the Starship pad is proposed has no access to the big flame trench.  That's probably not a problem for Starship, but it is for SuperHeavy.

What is the obsession with that trench? It's piled dirt with a high temperature concrete skin. A secondary one can easily be built.

Offline jstrotha0975

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #21 on: 07/06/2019 02:23 pm »
Where the Starship pad is proposed has no access to the big flame trench.  That's probably not a problem for Starship, but it is for SuperHeavy.

What is the obsession with that trench? It's piled dirt with a high temperature concrete skin. A secondary one can easily be built.

Why spend time and money building a new trench when you don't need one? Use the one that's already there.

Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #22 on: 07/06/2019 02:34 pm »
Why spend time and money building a new trench when you don't need one? Use the one that's already there.

Well frankly because I can see building one being cheaper than the money/time/flights lost if the test article explodes on the existing pad.

Offline jstrotha0975

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #23 on: 07/06/2019 02:45 pm »
Why spend time and money building a new trench when you don't need one? Use the one that's already there.

Well frankly because I can see building one being cheaper than the money/time/flights lost if the test article explodes on the existing pad.

The new proposed launch pad is still plenty close.

Offline speedevil

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #24 on: 07/06/2019 03:05 pm »
Why spend time and money building a new trench when you don't need one? Use the one that's already there.

Well frankly because I can see building one being cheaper than the money/time/flights lost if the test article explodes on the existing pad.
'The north side of the flame trench is 180m long,20 m wide and 14m high'.
As an admittedly silly example, deck barges are ~$2M new per 100*30m. Six laid down to make a deck of a trench, with eight stacked forming the sides gets you to pretty much the same dimension for very close on the order of $15M.

They don't even need to be well anchored as filling the top ones with a hundred thousand tons of water will keep them in place just fine.

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #25 on: 07/06/2019 04:15 pm »
Why spend time and money building a new trench when you don't need one? Use the one that's already there.

Well frankly because I can see building one being cheaper than the money/time/flights lost if the test article explodes on the existing pad.
'The north side of the flame trench is 180m long,20 m wide and 14m high'.
As an admittedly silly example, deck barges are ~$2M new per 100*30m. Six laid down to make a deck of a trench, with eight stacked forming the sides gets you to pretty much the same dimension for very close on the order of $15M.

They don't even need to be well anchored as filling the top ones with a hundred thousand tons of water will keep them in place just fine.

Not silly but I think your $2M / barge cost is a bit light.  I'm going to offer you a seat on the ISSS advocacy board and assign to you member number 2.   https://forum.nasaspaceflight.com/index.php?topic=47001.msg1962562#msg1962562
Actulus Ferociter!

Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #26 on: 07/06/2019 04:32 pm »
The new proposed launch pad is still plenty close.

Yes, but watch the Amos 6 static fire explosion, the most destructive part of the explosion is contained within the lightning towers. Anything could happen, starship could launch and go right into the main structure of 39A from a secondary pad, but a secondary pad still removes a lot of the risk to the main pad.

Everyone seems to be obsessed with that flame trench and cost of building one for a new pad. I see the possibility of losing the existing pad to an experimental system a far greater cost/risk proposition.

Offline matthewkantar

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #27 on: 07/06/2019 04:34 pm »
Why spend time and money building a new trench when you don't need one? Use the one that's already there.

Well frankly because I can see building one being cheaper than the money/time/flights lost if the test article explodes on the existing pad.
'The north side of the flame trench is 180m long,20 m wide and 14m high'.
As an admittedly silly example, deck barges are ~$2M new per 100*30m. Six laid down to make a deck of a trench, with eight stacked forming the sides gets you to pretty much the same dimension for very close on the order of $15M.

They don't even need to be well anchored as filling the top ones with a hundred thousand tons of water will keep them in place just fine.

Not silly but I think your $2M / barge cost is a bit light.  I'm going to offer you a seat on the ISSS advocacy board and assign to you member number 2.   https://forum.nasaspaceflight.com/index.php?topic=47001.msg1962562#msg1962562

May I suggest the first item on your agenda? To work toward a determination that barges are indeed LEGO elements. 

Online TheRadicalModerate

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #28 on: 07/06/2019 05:31 pm »
What is the obsession with that trench? It's piled dirt with a high temperature concrete skin. A secondary one can easily be built.

It's a fair question.

If you look at satellite photos, the current flame trench extends north, in line with the old crawler ramp (now the TE ramp), and the southward portion is divided in two by an island that forms the center part of the ramp, which supports the TE tower, while the transporter rails run along the outside edges of the ramp.

Recent FH launch video shows almost all of the exhaust going north.  Shuttle launches look like all the SSME exhaust goes south, while the SRB exhaust goes north.  And Apollo launches look like the exhaust is about equally distributed north and south.  (Do I have this right?)

The first thing to note is that the flame trench is an integral part of the pad itself.  I suspect that that means that building a new trench is pretty much equivalent to building a new pad.

The next thing to note is that the island in the center of the trench makes it very difficult to build a second launch mount very far to the south of the current launch mount and still use the trench.  I guess you could put a second TE mount just to the north of the island, but the stresses on the island would have to be taken into account.  And, if exhaust is mostly directed north, there's the whole issue of how you protect the existing mount and service structure from the exhaust.

Could you build an east-west flame trench?  Not without pretty much demolishing the ramp, which sounds like it would take the pad down for months if not years.

It looks to me that the flame "trench" for Starship tests, with a pad SSE of the main pad, would extend east, and would be pretty simple.  It doesn't have to handle huge amounts of exhaust.

I guess the question is whether that eastward trench, if built out more extensively, could handle SuperHeavy exhaust.  That seems... possible?  But the existing trench was designed to handle Saturn V mass flow and thrust, which is similar to SH, and it required bidirectional redirection of the exhaust.  A unidirectional trench therefore seems pretty iffy.

Seems like the only thing that's viable at 39A for SH is to re-do the launch mount to handle TE's for all 3 vehicles.  If Florida is only going to be used to handle high-inclination cargo launches for SH/SS, then maybe it can be horizontally integrated on some kind of super-TE, in which case maybe the service structure work isn't so bad.  But if SH/SS has to be vertically integrated or stacked, and it's hard to imagine 100 tonnes of payload being horizontally integrated, then using 39A is a real mess.

Of course, there's a pretty robust school of thought that says that LC-39B might be available in a few years.  It has a perfectly good flame trench already built.  Maybe doing a kludge at 39A for the early years of SH/SS isn't so bad if they can roll to a properly vertically-integrated system if/when SLS shuffles off this mortal coil.

Online TheRadicalModerate

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #29 on: 07/06/2019 05:40 pm »
The new proposed launch pad is still plenty close.

Yes, but watch the Amos 6 static fire explosion, the most destructive part of the explosion is contained within the lightning towers. Anything could happen, starship could launch and go right into the main structure of 39A from a secondary pad, but a secondary pad still removes a lot of the risk to the main pad.

Everyone seems to be obsessed with that flame trench and cost of building one for a new pad. I see the possibility of losing the existing pad to an experimental system a far greater cost/risk proposition.

Note that there's a pretty simple risk mitigation strategy here:  Do things at BC until you know what you're doing.

Florida has lots of nice properties for extensive suborbital tests of Starship.  But presumably suborbital follows hopper testing, which is more likely to cause massive destruction.  I'm betting that all hopper stuff will be done at BC, as well as early suborbits.  For the same reasons, I'm betting that most of the SuperHeavy qualification will occur at BC.

SpaceX needs SH/SS in Florida to access high-inclination orbits, but that's for an operational cargo system.  It would be (is) nice to access the assembly, integration, and ops expertise in Florida.  But it's not so nice that SpaceX would risk Commercial Crew or heavy DoD contracts.

Offline joek

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #30 on: 07/06/2019 06:38 pm »
... Florida has lots of nice properties for extensive suborbital tests of Starship.  But presumably suborbital follows hopper testing, which is more likely to cause massive destruction.  I'm betting that all hopper stuff will be done at BC, as well as early suborbits.  For the same reasons, I'm betting that most of the SuperHeavy qualification will occur at BC.

Agree up to the " SuperHeavy qualification will occur at BC"... depends on what you mean by "qualification"?

Quote
SpaceX needs SH/SS in Florida to access high-inclination orbits, but that's for an operational cargo system.  It would be (is) nice to access the assembly, integration, and ops expertise in Florida.  But it's not so nice that SpaceX would risk Commercial Crew or heavy DoD contracts.

Starlink is the priority "operational cargo system".  Orbits required by Starlink are going to be more difficult to reach from BC than FL.  That suggests FL will be priority for SS/SH operational flights.  Anyone have an analysis of the penalties Starlink launches from BC would incur (calling @OneSpeed and @speedevil)?

Not to mention that SS orbital reentry terminal phase from BC or FL will be over land, which may be the elephant in the room.[1]  In short, my vote goes to BC for hopper/SS tests; FL for SH full-up tests and SS/SH first operational flights.


[1] Long ago and far away Kistler obtained approval for similar, but that was over underpopulated areas and sparse air routes in Nevada (specifically, the Nevada Test Site).
« Last Edit: 07/06/2019 06:40 pm by joek »

Offline envy887

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #31 on: 07/06/2019 06:41 pm »
... Florida has lots of nice properties for extensive suborbital tests of Starship.  But presumably suborbital follows hopper testing, which is more likely to cause massive destruction.  I'm betting that all hopper stuff will be done at BC, as well as early suborbits.  For the same reasons, I'm betting that most of the SuperHeavy qualification will occur at BC.

Agree up to the " SuperHeavy qualification will occur at BC"... depends on what you mean by "qualification"?

Quote
SpaceX needs SH/SS in Florida to access high-inclination orbits, but that's for an operational cargo system.  It would be (is) nice to access the assembly, integration, and ops expertise in Florida.  But it's not so nice that SpaceX would risk Commercial Crew or heavy DoD contracts.

Starlink is the priority "operational cargo system".  Orbits required by Starlink are going to be more difficult to reach from BC than FL.  That suggests FL will be priority for SS/SH operational flights.  Anyone have an analysis of the penalties Starlink launches from BC would incur (calling @OneSpeed and @speedevil)?

Not to mention that SS orbital reentry terminal phase from BC or FL will be over land, which may be the elephant in the room.[1]  In short, my vote goes to BC for hopper/SS tests; FL for SH full-up tests and SS/SH first operational flights.


[1] Long ago and far away Kistler obtained approval for similar, but that was over underpopulated areas and sparse air routes in Nevada (specifically, the Nevada Test Site).

What about SuperHeavy hops without upper stage, if they do those?

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #32 on: 07/06/2019 07:07 pm »
Not to mention that SS orbital reentry terminal phase from BC or FL will be over land, which may be the elephant in the room.[1]  In short, my vote goes to BC for hopper/SS tests; FL for SH full-up tests and SS/SH first operational flights.

They have permission to do that with Dragon already (it is going to land very close to shore on the manned flights).  SS is a bit bigger, so that might affect the calculations.

Offline joek

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #33 on: 07/06/2019 07:10 pm »
What about SuperHeavy hops without upper stage, if they do those?

Good point... At BC?  Maybe.   Might allow them to do at least some SH qualification work at BC.  I could see building out some infrastructure at BC for such testing ahead of preparation for operational flights from BC in the more distant future.  But that still seems like a lot of infrastructure--even for stripped down (e.g., not all engines) SH tests.

Thus my interest in what is happening East of the BC hopper pad.  If we get clues it will be there.  Build a launch pad and flame trench suitable for SS only or for both SS and SH?  Would seem a small delta to build for both (although maybe not for a full SH engine complement)?

But getting a bit OT... my vote still for limited BC testing and FL for full-up testing and first operational flights.

Offline joek

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #34 on: 07/06/2019 07:31 pm »
Not to mention that SS orbital reentry terminal phase from BC or FL will be over land, which may be the elephant in the room.[1]  In short, my vote goes to BC for hopper/SS tests; FL for SH full-up tests and SS/SH first operational flights.
They have permission to do that with Dragon already (it is going to land very close to shore on the manned flights).  SS is a bit bigger, so that might affect the calculations.

Think "a bit bigger" is a bit of an understatement.  Not to mention Dragon will be under parachutes (at least we hope and expect), which while not providing the accuracy of a powered landing, also entails less risk than a powered landing to both sides--at least as presently determined.[1]

Not that the problem is insoluble.  Could aim for greater/safer off-shore (Eastward) entry point with SS and "bring it back to land" so to speak--at the expense of some propellant or cross-range maneuvers?  No idea what that would entail or the penalties involved.


[1] Starting to drift OT; not the thread to debate that subject (again).

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #35 on: 07/06/2019 07:50 pm »
Agree up to the " SuperHeavy qualification will occur at BC"... depends on what you mean by "qualification"?

"Qualification" = "Confident enough that you won't make a mess of the pad" in this case.

Quote
Starlink is the priority "operational cargo system".  Orbits required by Starlink are going to be more difficult to reach from BC than FL.  That suggests FL will be priority for SS/SH operational flights.  Anyone have an analysis of the penalties Starlink launches from BC would incur (calling @OneSpeed and @speedevil)?

I've done some work on that.  Assuming that launching over the Southeast US or Yucatan isn't allowed, the highest inclination you can get to is about 33 degrees, launching from BC through the Yucatan Channel.  I suspect that a dog-leg doesn't help very much, because by the time you clear Cancun, you're going fast enough that it's close to a full-up orbital plane change.

A plane change from 550x550x33 to 550x550x53 costs about 2600 m/s.  That's well beyond what Starship can do without on-orbit refueling, even if the payload is pretty small.  The low-inclination VLEO orbits cost between 1200 and 2000 m/s, which are somewhat better, but aren't going to get you as much as you'd get from a stretched-fairing FH3R launch from the Cape.

Quote
Not to mention that SS orbital reentry terminal phase from BC or FL will be over land, which may be the elephant in the room.[1]  In short, my vote goes to BC for hopper/SS tests; FL for SH full-up tests and SS/SH first operational flights.


[1] Long ago and far away Kistler obtained approval for similar, but that was over underpopulated areas and sparse air routes in Nevada (specifically, the Nevada Test Site).

That is indeed a fair-sized indoor pachyderm.  But EDL over CO, NM, and West Texas is pretty good from a sparse population standpoint.  Also, I wouldn't completely rule out that SpaceX might eventually put a landing pad somewhere really desolate (how 'bout White Sands?).  From there, getting a Starship back to either BC or MacGregor is pretty easy.  Wide loads, even 9m-wide loads, could probably be accommodated.

EDL into Florida is a horse of a different quantum number.
« Last Edit: 07/06/2019 08:21 pm by TheRadicalModerate »

Offline joek

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #36 on: 07/06/2019 08:37 pm »
That is indeed a fair-sized indoor pachyderm.  But EDL over CO, NM, and West Texas is pretty good from a sparse population standpoint.  Also, I wouldn't completely rule out that SpaceX might eventually put a landing pad somewhere really desolate (how 'bout White Sands?).  From there, getting a Starship back to either BC or MacGregor is pretty easy.  Wide loads, even 9m-wide loads, could probably be accommodated.

EDL into Florida is a horse of a different quantum number.

Kistler chose an area within the Nevada Test Site for a reason.  Not many sites which meet the criteria in the continental US.  Then again, that was then, this is now... Although SpaceX's demonstrated capability of more precise landings may allow other options (although that has been demonstrated only for suborbital, not for orbital reentry).

What would be the effect of making SS effective terminal entry point, e.g., 150mi East of FL or BC [1], and land from the East?  Likely someone around here can do the analysis?  (I have no idea.)


[1] 150mi arbitrary; no idea what might satisfy the FAA, at least for the near term.

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #37 on: 07/06/2019 08:49 pm »
...
I've done some work on that.  Assuming that launching over the Southeast US or Yucatan isn't allowed, the highest inclination you can get to is about 33 degrees, launching from BC through the Yucatan Channel.  I suspect that a dog-leg doesn't help very much, because by the time you clear Cancun, you're going fast enough that it's close to a full-up orbital plane change.

A plane change from 550x550x33 to 550x550x53 costs about 2600 m/s.  That's well beyond what Starship can do without on-orbit refueling, even if the payload is pretty small.  The low-inclination VLEO orbits cost between 1200 and 2000 m/s, which are somewhat better, but aren't going to get you as much as you'd get from a stretched-fairing FH3R launch from the Cape.
...

That strongly suggests priority for SS/SH operational launches (Starlink) is FL, not BC, and FL is where we should see SpaceX focusing their efforts for operational pad construction, yes?

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #38 on: 07/06/2019 10:50 pm »
May I suggest the first item on your agenda? To work toward a determination that barges are indeed LEGO elements.

Looks like it from here.
Actulus Ferociter!

Online TheRadicalModerate

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Re: SpaceX Cape 39A Starship launch/landing facilities
« Reply #39 on: 07/07/2019 03:27 am »
...
I've done some work on that.  Assuming that launching over the Southeast US or Yucatan isn't allowed, the highest inclination you can get to is about 33 degrees, launching from BC through the Yucatan Channel.  I suspect that a dog-leg doesn't help very much, because by the time you clear Cancun, you're going fast enough that it's close to a full-up orbital plane change.

A plane change from 550x550x33 to 550x550x53 costs about 2600 m/s.  That's well beyond what Starship can do without on-orbit refueling, even if the payload is pretty small.  The low-inclination VLEO orbits cost between 1200 and 2000 m/s, which are somewhat better, but aren't going to get you as much as you'd get from a stretched-fairing FH3R launch from the Cape.
...

That strongly suggests priority for SS/SH operational launches (Starlink) is FL, not BC, and FL is where we should see SpaceX focusing their efforts for operational pad construction, yes?

I think so.  But I still don't understand how they spin up launch facilities for the whole thing.  I just don't buy them launching that big a rocket from that tiny a pad, with no bidirectional flame trench.  My money's on horizontal integration for the time being, however much that limits the payload mass, because then the mods to 39A are probably doable between FH and CCP missions.

Anybody have an opinion on how big a payload (specifically a stack of Starlinks) you could horizontally integrate on a Starship?  If you need to use a 5-tonne PAF to keep it from torquing off the mount, that's probably fine, but at some point I'd guess the Starship structure will start to complain if you're trying to cantilever 100 tonnes off any kind of PAF.

Update:  I still think they'll work most of the kinks out in BC, because the consequences of blowing up 39A are very, very nasty.
« Last Edit: 07/07/2019 03:52 am by TheRadicalModerate »

 

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