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#120
by
scdavis
on 02 Aug, 2019 20:16
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What's an "impervious water percolation/retention pond"? Besides a Gator sanctuary I mean. 
A concrete pool, as opposed to pervious, which is just a hole dug in the ground.
Having lived in Florida, I'd like to suggest that a hole dug in the ground in Florida is... a pond. Almost immediately! The pervious retention area might be better to picture as a swamp than a hole.
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#121
by
Lisa_R4
on 02 Aug, 2019 20:35
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Page 7 lists Starship propellant capacity as "up to 1,500 MT" and Super Heavy with "up to 3,500 MT".
For reference the previous Starship propellant capacity was 1,100 MT.
Combining 1500t fuel with the "6.9km/s deltaV for a fully fueled Starship in orbit with 100t payload" tweet would imply a dry mass for Starship of ~180t assuming vac Raptors at 380s, or ~130t assuming sl Raptors at 350s as listed in the EA. Either seems reasonable enough given how little we know of the recent design changes.
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#122
by
Exastro
on 02 Aug, 2019 20:39
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Here's an interesting quote from Bezos that gives a glimpse into what the difficulty of landing an F9 booster compared to SH might be:
"In fact, the bigger the vehicle gets, the easier it is to land because it’s the inverted pendulum problem. New Shepard is the hardest vehicle to land that we’ll ever have to land."
Does this imply they never intend to land an upper stage?
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#123
by
Spindog
on 02 Aug, 2019 21:03
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So, how quickly will they be able to stack and launch tankers to refuel starship in orbit? At least a few will be needed for the DearMoon mission.
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#124
by
Joseph Peterson
on 02 Aug, 2019 21:50
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#125
by
geza
on 02 Aug, 2019 21:58
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Page 7 lists Starship propellant capacity as "up to 1,500 MT" and Super Heavy with "up to 3,500 MT".
For reference the previous Starship propellant capacity was 1,100 MT.
Combining 1500t fuel with the "6.9km/s deltaV for a fully fueled Starship in orbit with 100t payload" tweet would imply a dry mass for Starship of ~180t assuming vac Raptors at 380s, or ~130t assuming sl Raptors at 350s as listed in the EA. Either seems reasonable enough given how little we know of the recent design changes.
The earlier understanding about the dry mass of the SS was 85t. This was before the Stainless Steel Revolution. Surprise, surprise, stainless is heavier than carbon composit. Most probably the 85t figure did not take into account the need for heavy heat shielding properly.
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#126
by
DOCinCT
on 02 Aug, 2019 22:38
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Make Static Fires Great Again!
"Super Heavy booster static fire tests are planned to occur at LC-39A where all 31 engines are fired for 15 seconds"
Holy moly! 
Holy Moly indeed
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#127
by
Jcc
on 02 Aug, 2019 22:39
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Once past experimental, maximum load to orbit will be important, for example ror a refuelling trip, or to ensure the SS has as much propellant left for its mission.
Just like with F9, for higher energy missions the booster is landed out in the Atlantic. Therefore this will be (a) standard operating practice even if they do get to land the SH back on the coast (eventually) for some missions. (with a boostback burn etc.)
It sounds like they're going to be landing back near the coast, so the same fuel expenditure as a land landing.
As someone else said, this is minimum viable product stuff. Get it flying, get it working. This isn't the "final" plan, whatever the heck that will end up being
I realize that, it's just a hell of a way to start. At least they're landing by the coast, so shouldn't ever lose one or be forced to delay because of rough seas.
My guess is that they were told that SH landings would not be allowed until demonstrated... Hence the initial near-shore barge landings.
I would be surprised if that was the reason. I wouldn't think it's THAT much more dangerous at LZ-1 as the current F9 landings are (the empty tanks are full of explosive gas, but probably not enough to hurt anything from a crash at LZ-1). I thought it would have to do with no other suitable landing pad if SS has to come back right away.
"no closer than 20 miles s" sounds like it is phrased for noise mitigation. They may still recover downrange, and might come as close as 20 for test hops.
If they land ~20 mi down range they can get it back in a few hours, whereas 200 mi takes a couple of days, besides risking rough seas. I think they prefer closer even if it uses more fuel.
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#128
by
philw1776
on 02 Aug, 2019 22:40
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Page 7 lists Starship propellant capacity as "up to 1,500 MT" and Super Heavy with "up to 3,500 MT".
For reference the previous Starship propellant capacity was 1,100 MT.
Combining 1500t fuel with the "6.9km/s deltaV for a fully fueled Starship in orbit with 100t payload" tweet would imply a dry mass for Starship of ~180t assuming vac Raptors at 380s, or ~130t assuming sl Raptors at 350s as listed in the EA. Either seems reasonable enough given how little we know of the recent design changes.
The earlier understanding about the dry mass of the SS was 85t. This was before the Stainless Steel Revolution. Surprise, surprise, stainless is heavier than carbon composit. Most probably the 85t figure did not take into account the need for heavy heat shielding properly.
I'm not taking those 1500 & 3500 #s literally. They might be max rounded up figures for the purpose of approval. Then again, "only" 31 engines are cited, not 35 or whatever. We'll have more official #s hopefully later this month.
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#129
by
rakaydos
on 02 Aug, 2019 22:53
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Page 7 lists Starship propellant capacity as "up to 1,500 MT" and Super Heavy with "up to 3,500 MT".
For reference the previous Starship propellant capacity was 1,100 MT.
Combining 1500t fuel with the "6.9km/s deltaV for a fully fueled Starship in orbit with 100t payload" tweet would imply a dry mass for Starship of ~180t assuming vac Raptors at 380s, or ~130t assuming sl Raptors at 350s as listed in the EA. Either seems reasonable enough given how little we know of the recent design changes.
The earlier understanding about the dry mass of the SS was 85t. This was before the Stainless Steel Revolution. Surprise, surprise, stainless is heavier than carbon composit. Most probably the 85t figure did not take into account the need for heavy heat shielding properly.
I'm not taking those 1500 & 3500 #s literally. They might be max rounded up figures for the purpose of approval. Then again, "only" 31 engines are cited, not 35 or whatever. We'll have more official #s hopefully later this month.
I suspect the 1100 ton figure as accurate for the mk 1 starships, and the 1500 ton figure to be accurate for the eventual dedicated tanker designs.
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#130
by
Lisa_R4
on 02 Aug, 2019 22:56
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I'm not taking those 1500 & 3500 #s literally. They might be max rounded up figures for the purpose of approval.
Perhaps up to 1500t would be a better estimate for how much a dedicated tanker SS might carry whenever they get around to making one.
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#131
by
meekGee
on 02 Aug, 2019 23:50
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Page 7 lists Starship propellant capacity as "up to 1,500 MT" and Super Heavy with "up to 3,500 MT".
For reference the previous Starship propellant capacity was 1,100 MT.
Combining 1500t fuel with the "6.9km/s deltaV for a fully fueled Starship in orbit with 100t payload" tweet would imply a dry mass for Starship of ~180t assuming vac Raptors at 380s, or ~130t assuming sl Raptors at 350s as listed in the EA. Either seems reasonable enough given how little we know of the recent design changes.
The earlier understanding about the dry mass of the SS was 85t. This was before the Stainless Steel Revolution. Surprise, surprise, stainless is heavier than carbon composit. Most probably the 85t figure did not take into account the need for heavy heat shielding properly.
How are you calculating this without knowing how much propellant is left over at the end? I see why you'd want to argue "zero", but it's not really certain. They say "in orbit" so should we add de-orbit, landing, and any residual fuel?
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#132
by
Steve D
on 02 Aug, 2019 23:54
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Page 7 lists Starship propellant capacity as "up to 1,500 MT" and Super Heavy with "up to 3,500 MT".
For reference the previous Starship propellant capacity was 1,100 MT.
Combining 1500t fuel with the "6.9km/s deltaV for a fully fueled Starship in orbit with 100t payload" tweet would imply a dry mass for Starship of ~180t assuming vac Raptors at 380s, or ~130t assuming sl Raptors at 350s as listed in the EA. Either seems reasonable enough given how little we know of the recent design changes.
The earlier understanding about the dry mass of the SS was 85t. This was before the Stainless Steel Revolution. Surprise, surprise, stainless is heavier than carbon composit. Most probably the 85t figure did not take into account the need for heavy heat shielding properly.
85 ton starship, 100 tons cargo.
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#133
by
xyv
on 03 Aug, 2019 01:15
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I think everybody is placing entirely too much faith in what are preliminary (and outdated) numbers. An EIS is to let the appropriate authorities evaluate impacts. It's much more important to get a baseline and iterate than wait for perfection. My brief foray into Rockets involved the SLC-6 modification for the Space Shuttle. The EIS was over 900 pages in several volumes and was updated on a 6 month cadence. The specific details in this report (think 4 decimal place engine geometries) are there to anchor the impact analysis that follows. Updates to the inputs (e.g. 35 engines...) will update the impacts.
Another thought. How are those detailed engine geometries (out of date as they may be...) not ITAR?
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#134
by
speedevil
on 03 Aug, 2019 03:33
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I'm not taking those 1500 & 3500 #s literally. They might be max rounded up figures for the purpose of approval.
Perhaps up to 1500t would be a better estimate for how much a dedicated tanker SS might carry whenever they get around to making one.
The 2017 weights were ~85 tons dry + 7 tons prop for landing + 150, or close on 240 tons, plus 1100 tons prop = 1340 or so.
The comment at sxsw was made that you can get 300 tons with expendable would take the maximum mass to ~1492t.
(I am not saying anything particular should be drawn from these numbers, and especially don't believe any attempt to come up with a dry mass for SS that is dramatically in conflict with statements about SS being lighter).
Given that we're hopefully getting updates in a week or two, dragging numbers together from 2016-2019 makes less than 0 sense.
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#135
by
FutureSpaceTourist
on 03 Aug, 2019 03:56
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What's an "impervious water percolation/retention pond"? Besides a Gator sanctuary I mean.
A concrete pool, as opposed to pervious, which is just a hole dug in the ground.
It’s discussed in several places in the EA, for example on p69:
Launch deluge and pad washdown water generated from the new Starship/Super Heavy launch pad at LC-39A would be isolated from the existing Falcon 9/Heavy deluge system and flow into a new containment (impervious basin) and disposal (percolation pond) system shown in Figure 2-2. This system would be designed to satisfy FDEP industrial wastewater permitting requirements for attenuation and onsite disposal of launch-related wastewater. Industrial wastewater would be contained in an impervious basin until discharge water quality criteria set in the FDEP permit are met, and released into a pervious percolation area for dissipation into the surficial water table. No chemical treatment of deluge wastewater is anticipated.
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#136
by
Ludus
on 03 Aug, 2019 07:01
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Here's an interesting quote from Bezos that gives a glimpse into what the difficulty of landing an F9 booster compared to SH might be:
"In fact, the bigger the vehicle gets, the easier it is to land because it’s the inverted pendulum problem. New Shepard is the hardest vehicle to land that we’ll ever have to land."
Does this imply they never intend to land an upper stage?
New Shepard would be smaller than New Glenn’s upper stage.
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#137
by
edkyle99
on 03 Aug, 2019 13:57
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"SpaceX plans to launch the Starship/Super Heavy up to 24 times per year from LC-39A. A static fire test would be conducted on each stage prior to each launch."
Yes, but it also says:
"The Starship and Super Heavy would exceed the lift capabilities of the Falcon Heavy. Due to the higher lift capability, Starship/Super Heavy could launch more payloads and reduce the overall launch cadence when compared to Falcon 9 and Falcon Heavy. This would increase the cost effectiveness of the space industry."
Sounds like STS, or Titan IV, or EELV. Fewer launches, more stuff on each. Initial claims of cost-effectiveness that didn't pan out in those cases.
- Ed Kyle
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#138
by
M.E.T.
on 03 Aug, 2019 14:07
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"SpaceX plans to launch the Starship/Super Heavy up to 24 times per year from LC-39A. A static fire test would be conducted on each stage prior to each launch."
Yes, but it also says:
"The Starship and Super Heavy would exceed the lift capabilities of the Falcon Heavy. Due to the higher lift capability, Starship/Super Heavy could launch more payloads and reduce the overall launch cadence when compared to Falcon 9 and Falcon Heavy. This would increase the cost effectiveness of the space industry."
Sounds like STS, or Titan IV, or EELV. Fewer launches, more stuff on each.
- Ed Kyle
That would be a reduction compared to the number of F9/FH launches required to launch the same tonnage to space, whatever that annual planned tonnage may be in future. Not a reduction compared to current F9/FH launch cadence.
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#139
by
su27k
on 03 Aug, 2019 14:31
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"SpaceX plans to launch the Starship/Super Heavy up to 24 times per year from LC-39A. A static fire test would be conducted on each stage prior to each launch."
Yes, but it also says:
"The Starship and Super Heavy would exceed the lift capabilities of the Falcon Heavy. Due to the higher lift capability, Starship/Super Heavy could launch more payloads and reduce the overall launch cadence when compared to Falcon 9 and Falcon Heavy. This would increase the cost effectiveness of the space industry."
Sounds like STS, or Titan IV, or EELV. Fewer launches, more stuff on each. Initial claims of cost-effectiveness that didn't pan out in those cases.
- Ed Kyle
I think this paragraph is obviously written with Starlink in mind, one Starship launch can probably replace 7 Falcon 9 Starlink launches, big savings for SpaceX, also reduces the launch congestion at the Cape.
