Author Topic: New Glenn: Blue Origin Announcement of Orbital Rocket Plan  (Read 1120209 times)

Offline envy887

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1740 on: 08/16/2020 06:01 pm »
Throttle range for BE-4 is 45%-100% or 2400 kN down to 1080 kN. It therefore takes residual fuel and stage mass of 110 t or higher to be able to "hover" or do a New Shepard like controlled descent.
Let's compare to SpaceX, which has an empty mass of about 27t, and a minimum hovering mass of 35t.   7 BE-4 engines provide about 2.2 times the thrust of 9 Merlin 1Ds. So scaling up, BO could presumably build a booster mass with a mass of about 27 x 2.2 = 60t.  That's 50t less than the hovering mass, and compared to a booster that could hover, would increase their payload by 4-5t.
[...]
So I'm guessing they will end up with a first stage empty mass of about 80t.  That gives them 20t to spend on robustness, and the same landing thrust/mass as SpaceX, which is known to work.  Adding another 30t to let them hover seems wasteful.
On the other hand, they can afford a booster dry mass of well over 100 t and still easily hit the published performance, by my calculations. Why over-engineer the booster if you have mass to spend?
That's placing a bet at design time that they will never be mass limited.  The 45t to LEO is expendable, which will seldom be used.   With re-use, expect about 34t, based on SpaceX ( 2.2 thrust ratio times 15.6t payload).  Will this ever get maxed out?  For SpaceX, the most numerous launches (satellite constellation) are indeed mass limited.  Comsat launches will likely be mass limited (a rough guess shows one big and one small might allow recovery, but two big comsats will need expendable).  Possible future uses (such as fuel delivery) can easily be mass limited.

So in my opinion, BO would be unwise to give up mass to orbit in favor of (unneeded) ability to hover.
45 t to LEO is not expendable. It's also not a particularly optimistic figure.

If Blue is even moderately aggressive on dry mass fractions, New Glenn should be capable of 50-55 t with booster recovery and 65-70 t expendable.

Offline ZachF

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1741 on: 08/16/2020 06:39 pm »
Throttle range for BE-4 is 45%-100% or 2400 kN down to 1080 kN. It therefore takes residual fuel and stage mass of 110 t or higher to be able to "hover" or do a New Shepard like controlled descent.
Let's compare to SpaceX, which has an empty mass of about 27t, and a minimum hovering mass of 35t.   7 BE-4 engines provide about 2.2 times the thrust of 9 Merlin 1Ds. So scaling up, BO could presumably build a booster mass with a mass of about 27 x 2.2 = 60t.  That's 50t less than the hovering mass, and compared to a booster that could hover, would increase their payload by 4-5t.

Now New Glenn is big already, so maybe they don't need the extra payload, and would like to use some of that mass to make the first stage more robust (although SpaceX, at this mass, is already re-using the booster 5 times).  But I can't imagine them almost doubling the mass over what they need - they should be able to get 25 uses with less overhead.

So I'm guessing they will end up with a first stage empty mass of about 80t.  That gives them 20t to spend on robustness, and the same landing thrust/mass as SpaceX, which is known to work.  Adding another 30t to let them hover seems wasteful.

New Glenn first stage will probably mass ~100 tonnes empty. It likely holds ~1150 tonnes of fuel (almost as much as starship's upper stage), and if you account for its lower density the volume of the tankage is probably higher.

27 tonnes for Falcon 9 lower stage is about 6.5% of the fueled mass of the booster. 80 tonnes dry with about 1150 tonnes is about 6.9%, which is IMHO unrealistic considering the large strakes that are not on Falcon, fuel that is about 30% more dense on Falcon(~1.07 v ~0.82), and Merlin probably has twice the TWR of the BE-4.

« Last Edit: 08/16/2020 06:47 pm by ZachF »
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Offline ZachF

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1742 on: 08/16/2020 08:01 pm »
Here are my estimates for New Glenn's stats, with explanations for how they were derived... I have pretty high confidence in the numbers, as they all seem to corroborate each other.

BE-4
ER=23
How? Pixel measurements and photographs

3.2:1 mixture ratio
How? Pixel measurements on both Vulcan and New Glenn tank volumes seem to suggest this number

ISP: 310 SL, 340 Vac
How?: This is roughly the performance that a 134bar, ER=23, 3.2:1 rocket should achieve

TWR: 90
How? A bit better than the RD-180

First Stage:
Fuel load: 1150 tonnes
How? BE-4 with 2,440kN of thrust, and an ISP ~310 should have a mass flow rate of ~803kg/s. We know from the payload users guide that the engines burn for 200 seconds. 200s x 7eng x ~803kg = 1,124,200kg. This number should have a pretty high fidelity, being off on ISP by 3 only changes the final number by ~10 tonnes. Subtract out some for a likely throttle down during Max-Q and during the end of the burn to limit Gs under 4 then add back in the landing fuel and you likely arrive at ~1,150 tonnes.

Empty mass: ~100 tonnes
How? Falcon 9's first stage weighs about 27 tonnes vs. ~409 tonnes of fuel. Falcon 9 also has fuel that is 30% more dense, doesn't have large strakes, and the TWR for Merlin is probably about twice as high as BE-4.

BE-3U
ER=85
How? Pixel measurements and photographs

4.65:1 mixture ratio
How? Pixel measurements on tank volumes seem to suggest a pretty highly fuel rich engine, under 5 for sure.

ISP: 445 Vac
HOw?The mixture ratio and expansion ratio numbers above are very close to the HM-7B, and the BE-3U also uses open-cycle turbines as well. Those all have ISPs in the 442-446 range. ISP above 450 is almost certainly out, given the open cycle turbines.

Chamber pressure: ~54 bar
How?: This is roughly the chamber pressure that would be needed with the above estimated numbers and published thrust numbers (530kN) and nozzle exit size (2.4m)

Second stage
Fuel mass: 175 tonnes
How? Like with the estimation for first stage fuel, Blue has published the burn times for it's upper stage as well. The second stage burns 618 seconds to it's parking orbit, then 99 seconds to GTO, for a total of 717 seconds. The payload users guide publishes 1060kN for the upper stage thrust. With an ISP of 445, this would yield a second stage mass flow rate of 243kg/s. 243kg x 717s = 174,231kg. Add in 800 kg for reserve... 175 tonnes.

Empty mass: ~16.7 tonnes.
How? The payload users guide lists a 99 second burn time to reach GTO from parking orbit. We know that this maneuver takes a dV of around 2,500 m/s. Now, a 99 second burn will use 24,057kg of fuel (99s x 243kg). Using the rocket equation and the above estimated ISP, e^(2500/4361) = 1.774 for a mass ratio before and after the burn. With the amount of fuel burned, and the mass ratio, we can now estimate the mass of the rocket before and after the burn.  This yields and intial mass of 55,137kg, and a final mass of 31,080kg. Blue Origin lists the GTO payload at 13,600kg. Subtracting the two yields, 17,480kg. Subtracting 800kg for fuel reserve yields ~16.7 tonnes.

Payload fairing: 6 tonnes
How? The Falcon 9 payload fairing is a little less than half the size of the NG PLF, and weighs 2.6 tonnes.

------------------
Adding all of this together gets you a GLOW of 1,461,300 kg. Liftoff TWR is 1750/1461.3 = 1.198 Pretty much exactly where you'd expect it to be.  :) Again these numbers all seem to corroborate very well together.
« Last Edit: 08/16/2020 08:53 pm by ZachF »
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Offline ZachF

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1743 on: 08/16/2020 08:22 pm »
Another interesting tidbit in the Payload Users Guide, The second stage only burns for 600 seconds during a LEO payoad vs 717 seconds for a GTO payload. This means that Blue is likely partial-loading the second stage by roughly the difference in payloads so that the first stage reentry profile can stay the same for both GTO and LEO payloads. 117 fewer seconds is 28.4 fewer tonnes of fuel. 13.6t + 28.4t = 42 t

This also means that staging velocity is going to be pretty much static, making it easy to guess payloads to other orbits...

GTO-1800: ~13,600kg (given)
GTO-1700: ~12,800kg (supersynch)
GTO-1600: ~11,200kg (supersynch)
GTO-1500: ~10,100kg (supersynch)
GTO-1000: ~7,600kg (perigee raise + inc)
GTO-500: ~4,500kg (perigee raise + inc)
GEO Direct: ~1,800kg
TLI: ~7,800kg
TMI: ~4,700kg

Payload to higher dVs look like they are going to suffer on this rocket without a third stage because of the high second stage mass.
« Last Edit: 08/16/2020 08:31 pm by ZachF »
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Offline GWH

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1744 on: 08/16/2020 09:56 pm »
Great work, one issue with the higher dV numbers you give is they wouldn't meet all the NSSL requirements to GEO. This means they would need a 3rd stage to hit. Blue has claimed they could do all orbits in a single configuration.

https://www.blueorigin.com/news/be4-to-support-national-security-space-launch-program
Quote
single basic launch service price for any mission across the entire ordering period.
« Last Edit: 08/16/2020 10:01 pm by GWH »

Offline armchairfan

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1745 on: 08/16/2020 11:18 pm »
Great work, one issue with the higher dV numbers you give is they wouldn't meet all the NSSL requirements to GEO. This means they would need a 3rd stage to hit. Blue has claimed they could do all orbits in a single configuration.

https://www.blueorigin.com/news/be4-to-support-national-security-space-launch-program
Quote
single basic launch service price for any mission across the entire ordering period.
I have no special insight, but a literal reading of that Blue news release doesn't claim a single configuration, only a single price. Perhaps they just throw in a Star48B "for free" for those few GEO direct launches that need it. Think of it as a loss-leader necessary to get the contract.

Assuming a Star48B can survive the coast to GTO apogee, I get an additional DV of about 2400 732 m/s for the max NSSL GEO payload (6600 kg). Total mass with Star48B and NSSL payload is 8700 kg so not well within ZachF's GTO numbers.

Edit: Nevermind. That'll teach me to avoid posting numbers that don't make intuitive sense. (I misapplied my spreadsheet.)

Nothing to see here; carry on. :-[
« Last Edit: 08/16/2020 11:31 pm by armchairfan »

Offline ZachF

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1746 on: 08/16/2020 11:36 pm »
Great work, one issue with the higher dV numbers you give is they wouldn't meet all the NSSL requirements to GEO. This means they would need a 3rd stage to hit. Blue has claimed they could do all orbits in a single configuration.

https://www.blueorigin.com/news/be4-to-support-national-security-space-launch-program
Quote
single basic launch service price for any mission across the entire ordering period.

They could if they expend the booster, or with a hypergolic kick stage.

IMHO, there is no way this upper stage could get 6000kg to GEO unless it's dry mass is *unrealistically* low.

« Last Edit: 08/16/2020 11:43 pm by ZachF »
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Offline GWH

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1747 on: 08/17/2020 12:17 am »
They could if they expend the booster, or with a hypergolic kick stage.

IMHO, there is no way this upper stage could get 6000kg to GEO unless it's dry mass is *unrealistically* low.

There's no way expending a booster that doesn't do boost back or reentry burns is going to triple payload.

The quote I posted was also vague, this one isn't:
Quote
“If you look at LSA and all those mission profiles, we can serve all of those with a single version of New Glenn with this two-stage architecture,” Mowry said.
https://spacenews.com/blue-origin-switches-engines-for-new-glenn-second-stage/

With estimating staging velocity from burn time alone, there isn't any provision being made for a lofted trajectory, engine throttling, or gravity losses. All those things could provide some variation that might not be accounted for.

The Payload Users's guide puts MECO for a GTO mission at 2700 m/s (see chart on page 29).

That all aligns to me running some basic numbers at 175 tonnes propellant and 0.9 propellant mass fraction to hit the GTO AND GEO numbers, then 12,000 or so to TLI.

Offline TrevorMonty

They could still do 3rd stage, which would increase BLEO performance, approx 17mt to TLI. Stage is just smaller single engine version of 2nd stage so not lot of development or special tooling needed.

Have to trade 1 3stage launch of 17mt against 2 2stage launches for combined 24mt. Probably not a lot in it between two versions for $kg to TLI. 3stage has higher risk factor. TLI is likely to be Blue's main BLEO destination besides GTO.



« Last Edit: 08/17/2020 02:55 am by TrevorMonty »

Offline yoram

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1749 on: 08/17/2020 03:01 am »
Also the initial specs are likely very conservative. It wouldn't surprise me if they can squeeze out a lot more as they gain more experience.

Offline TorenAltair

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1750 on: 08/17/2020 12:07 pm »
Small thing about your numbers, ZachF. Blue Origin‘s „New Glenn“ website section states the upper stage thrust as 1100kN (2x 550kN). You used 530kN. Their „Engines“ section on the webpage quotes 710kN for the BE-3U engine.

Offline ZachF

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1751 on: 08/17/2020 12:14 pm »
They could if they expend the booster, or with a hypergolic kick stage.

IMHO, there is no way this upper stage could get 6000kg to GEO unless it's dry mass is *unrealistically* low.

There's no way expending a booster that doesn't do boost back or reentry burns is going to triple payload.


You need to include the mass of the empty stage.

It's not triple because the mass of the empty stage dominates the the total mass sent to a given dV when you get towards the far end of rocket performance. Eventually it reaches zero.

With an empty mass of 16.7 tonnes, that means that ~90% of the mass sent to GEO would be the empty stage if payload is 1800kg. Increasing the payload to 6000 kg from 1800 kg increases the mass of the spent rocket + payload from 18,500kg to 22,700kg, or 22.7%.... not triple.

New Glenn has a massive second stage. It's about as large as an Ariane 5 core stage, and it has a larger volume than a Falcon 9 first stage tank.
« Last Edit: 08/17/2020 12:18 pm by ZachF »
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Offline ZachF

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1752 on: 08/17/2020 12:16 pm »
Small thing about your numbers, ZachF. Blue Origin‘s „New Glenn“ website section states the upper stage thrust as 1100kN (2x 550kN). You used 530kN. Their „Engines“ section on the webpage quotes 710kN for the BE-3U engine.

Payload users guide states 1060kN for the upper stage, that is the most up to date, and since it is sent out to prospective customers, I expect that to have the most accurate info.
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Offline ZachF

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1753 on: 08/17/2020 12:25 pm »
They could still do 3rd stage, which would increase BLEO performance, approx 17mt to TLI. Stage is just smaller single engine version of 2nd stage so not lot of development or special tooling needed.

Have to trade 1 3stage launch of 17mt against 2 2stage launches for combined 24mt. Probably not a lot in it between two versions for $kg to TLI. 3stage has higher risk factor. TLI is likely to be Blue's main BLEO destination besides GTO.

I suspect they will do a 3rd stage with ultra-high ER BE-7s.

Dual closed expander engine with a very high ER could easily get ISP in the high 460s, much higher than the BE-3U. A third stage with a few of these engines would provide very large performance out to high C3 orbits.
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Offline TrevorMonty

They could still do 3rd stage, which would increase BLEO performance, approx 17mt to TLI. Stage is just smaller single engine version of 2nd stage so not lot of development or special tooling needed.

Have to trade 1 3stage launch of 17mt against 2 2stage launches for combined 24mt. Probably not a lot in it between two versions for $kg to TLI. 3stage has higher risk factor. TLI is likely to be Blue's main BLEO destination besides GTO.

I suspect they will do a 3rd stage with ultra-high ER BE-7s.

Dual closed expander engine with a very high ER could easily get ISP in the high 460s, much higher than the BE-3U. A third stage with a few of these engines would provide very large performance out to high C3 orbits.
3rd stage is all about low mass and high ISP, high thrust isn't as important. So a few BE7 may workout better for mass and ISP.

Offline GWH

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1755 on: 08/17/2020 01:22 pm »
Small thing about your numbers, ZachF. Blue Origin‘s „New Glenn“ website section states the upper stage thrust as 1100kN (2x 550kN). You used 530kN. Their „Engines“ section on the webpage quotes 710kN for the BE-3U engine.

Payload users guide states 1060kN for the upper stage, that is the most up to date, and since it is sent out to prospective customers, I expect that to have the most accurate info.


It's not just their website but also this video covering propulsion from September 2019, the PUG is dated October 2018. Unless you have a newer copy than Rev C?




You need to include the mass of the empty stage.

What staging velocity do you assume? Does it match the staging velocity GIVEN in the PUG? If not then you'll end up shooting low on payload estimates.  I understand the effect of dry mass on payload (it is huge on New Glenn) and have the spreadsheet to prove it ;)  (plus CAD scaling of New Glenn)
« Last Edit: 08/17/2020 02:01 pm by GWH »

I was thinking that, now that they've lost the NSSL contract, Blue Origin would probably stop whatever 3rd stage development they may have been doing, and focus on dual launch and orbital refueling. But they only have one pad, and one ship, so a BE-7 3rd stage may be the best short-term option for increasing their TLI tonnage (assuming they feel a need to).
Wait, ∆V? This site will accept the ∆ symbol? How many times have I written out the word "delta" for no reason?

Offline envy887

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1757 on: 08/18/2020 01:35 pm »
Another interesting tidbit in the Payload Users Guide, The second stage only burns for 600 seconds during a LEO payoad vs 717 seconds for a GTO payload. This means that Blue is likely partial-loading the second stage by roughly the difference in payloads so that the first stage reentry profile can stay the same for both GTO and LEO payloads. 117 fewer seconds is 28.4 fewer tonnes of fuel. 13.6t + 28.4t = 42 t

This also means that staging velocity is going to be pretty much static, making it easy to guess payloads to other orbits...

GTO-1800: ~13,600kg (given)
GTO-1700: ~12,800kg (supersynch)
GTO-1600: ~11,200kg (supersynch)
GTO-1500: ~10,100kg (supersynch)
GTO-1000: ~7,600kg (perigee raise + inc)
GTO-500: ~4,500kg (perigee raise + inc)
GEO Direct: ~1,800kg
TLI: ~7,800kg
TMI: ~4,700kg

Payload to higher dVs look like they are going to suffer on this rocket without a third stage because of the high second stage mass.

When I plug your dry mass, propellant load, and specific impulse estimates into the Silverbird calculator with 0.5% residuals, I get:

185 km LEO: 62.6 t
35785 x 185 km, 28 deg GTO: 24.5 t
35785 x 35785, 28 deg: 11.6 t
35785 x 35785 km, 0 deg GEO: 9.2 t

I'm not making any adjustments to reserve fuel for landing, so this would be expendable. But it appears that New Glenn is more than capable of hitting all the NSSL orbits if expended.

Reserving 30 t of prop for landing (770 m/s), it still can get 7.23 t to 35785 x 35785 km, 0 deg.

Offline ncb1397

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1758 on: 08/18/2020 02:53 pm »
Another interesting tidbit in the Payload Users Guide, The second stage only burns for 600 seconds during a LEO payoad vs 717 seconds for a GTO payload. This means that Blue is likely partial-loading the second stage by roughly the difference in payloads so that the first stage reentry profile can stay the same for both GTO and LEO payloads. 117 fewer seconds is 28.4 fewer tonnes of fuel. 13.6t + 28.4t = 42 t

This also means that staging velocity is going to be pretty much static, making it easy to guess payloads to other orbits...

GTO-1800: ~13,600kg (given)
GTO-1700: ~12,800kg (supersynch)
GTO-1600: ~11,200kg (supersynch)
GTO-1500: ~10,100kg (supersynch)
GTO-1000: ~7,600kg (perigee raise + inc)
GTO-500: ~4,500kg (perigee raise + inc)
GEO Direct: ~1,800kg
TLI: ~7,800kg
TMI: ~4,700kg

Payload to higher dVs look like they are going to suffer on this rocket without a third stage because of the high second stage mass.

When I plug your dry mass, propellant load, and specific impulse estimates into the Silverbird calculator with 0.5% residuals, I get:

185 km LEO: 62.6 t
35785 x 185 km, 28 deg GTO: 24.5 t
35785 x 35785, 28 deg: 11.6 t
35785 x 35785 km, 0 deg GEO: 9.2 t

I'm not making any adjustments to reserve fuel for landing, so this would be expendable. But it appears that New Glenn is more than capable of hitting all the NSSL orbits if expended.

Reserving 30 t of prop for landing (770 m/s), it still can get 7.23 t to 35785 x 35785 km, 0 deg.

I get 5035 kg with a 95% confidence level of 2006-8581 kg. But I threw 5,000 kg and 200 second disposal at the fairing (Just a wag really). GEO with a 2 stage vehicle is pretty tough. Vulcan and Falcon Heavy have an advantage in that regard.

edit: Just saw that the fairing was defined at 6000 kg. Think the discrepancy was I was using the conservative sea level isp of 310 rather than vacuum.
« Last Edit: 08/18/2020 03:00 pm by ncb1397 »

Offline envy887

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Re: New Glenn: Blue Origin Announcement of Orbital Rocket Plan
« Reply #1759 on: 08/18/2020 10:26 pm »
Another interesting tidbit in the Payload Users Guide, The second stage only burns for 600 seconds during a LEO payoad vs 717 seconds for a GTO payload. This means that Blue is likely partial-loading the second stage by roughly the difference in payloads so that the first stage reentry profile can stay the same for both GTO and LEO payloads. 117 fewer seconds is 28.4 fewer tonnes of fuel. 13.6t + 28.4t = 42 t

This also means that staging velocity is going to be pretty much static, making it easy to guess payloads to other orbits...

GTO-1800: ~13,600kg (given)
GTO-1700: ~12,800kg (supersynch)
GTO-1600: ~11,200kg (supersynch)
GTO-1500: ~10,100kg (supersynch)
GTO-1000: ~7,600kg (perigee raise + inc)
GTO-500: ~4,500kg (perigee raise + inc)
GEO Direct: ~1,800kg
TLI: ~7,800kg
TMI: ~4,700kg

Payload to higher dVs look like they are going to suffer on this rocket without a third stage because of the high second stage mass.

When I plug your dry mass, propellant load, and specific impulse estimates into the Silverbird calculator with 0.5% residuals, I get:

185 km LEO: 62.6 t
35785 x 185 km, 28 deg GTO: 24.5 t
35785 x 35785, 28 deg: 11.6 t
35785 x 35785 km, 0 deg GEO: 9.2 t

I'm not making any adjustments to reserve fuel for landing, so this would be expendable. But it appears that New Glenn is more than capable of hitting all the NSSL orbits if expended.

Reserving 30 t of prop for landing (770 m/s), it still can get 7.23 t to 35785 x 35785 km, 0 deg.

I get 5035 kg with a 95% confidence level of 2006-8581 kg. But I threw 5,000 kg and 200 second disposal at the fairing (Just a wag really). GEO with a 2 stage vehicle is pretty tough. Vulcan and Falcon Heavy have an advantage in that regard.

edit: Just saw that the fairing was defined at 6000 kg. Think the discrepancy was I was using the conservative sea level isp of 310 rather than vacuum.

I also used 1400 kN for the upper stage thrust, which does make a difference since it stages pretty slow even fully expendable. But the lower booster ISP probably makes a bigger difference. 310 SL, 330 vac is not very aggressive.

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