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   Charlie Stross (cstross@wandering.shop)'s status on Friday, 17-Jan-2025 00:03:35 JST Charlie Stross

   Random Q: does anyone know how much a fully fuelled New Glenn stack (without payload) weighs on the launchpad? Nothing in Wikipedia, nothing in Encyclopedia Astronautica, nothing on Blue Origin's website …

   I'm guessing about 1700 tonnes (going by lift-off t:w ratio of about 1.1 and 2450kN thrust per BE-4 engine) but I've got a nerdish wish to be accurate.

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     Charlie Stross (cstross@wandering.shop)'s status on Friday, 17-Jan-2025 00:18:02 JST Charlie Stross

     in reply to

     Anyway, if 1400 tonnes is in the right ball-park for New Glenn, then it's half the mass of a Saturn V and almost a quarter the mass of Starship v2.

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     Charlie Stross (cstross@wandering.shop)'s status on Friday, 17-Jan-2025 01:08:13 JST Charlie Stross

     in reply to

     • Administrator

     @mdm How many times has the BE-2 engine flown? I make it 4 on Vulkan and now 7 on New Glenn. So they're barely into double-digits of flight-rated motors. I suspect that, like Merlin and Raptor, the BE-2 will be tweaked to produce more thrust in due course.

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     Administrator (mdm@mcnamarii.town)'s status on Friday, 17-Jan-2025 01:08:14 JST Administrator

     in reply to

     @cstross ...based on how slowly it lifted off, they've either got to drop that mass (carry less fuel?) or add another engine (probably not possible).

     But a very impressive launch, nonetheless!

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     Charlie Stross (cstross@wandering.shop)'s status on Friday, 17-Jan-2025 01:08:33 JST Charlie Stross

     in reply to

     • crater🐮n

     @cratermoon Doesn't look that way.

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     crater🐮n (cratermoon@zirk.us)'s status on Friday, 17-Jan-2025 01:08:35 JST crater🐮n

     in reply to

     @cstross Side note: has Encyclopedia Astronautica been updated since about 2018-2019?

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     Charlie Stross (cstross@wandering.shop)'s status on Friday, 17-Jan-2025 03:40:41 JST Charlie Stross

     in reply to

     • Administrator

     @mdm Bezos has already shaken up the launch industry: ULA's Vulkan rides on a pair of BE-4s, has comparable payload to Falcon 9,, and ULA will have to bite the bullet and go for reusability or be roadkill.

     (I half-expect Blue Origin to buy ULA and position these rockets as a family of medium and heavy weight lifters with significant parts commonality.)

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     Administrator (mdm@mcnamarii.town)'s status on Friday, 17-Jan-2025 03:40:43 JST Administrator

     in reply to

     @cstross (BE-4, right?)

     I was looking up some quick stats, and it seems like each BE-4 engine is very close to SpaceX's raptor (around 500k freedom units of force). I don't know how much more power they can get out of a BE-4.

     That being said, SpaceX is cramming 33 similar engines into one booster. I have no idea how -- I guess the 2 meters more diameter makes a difference.

     I never thought I'd say this, but I am really rooting for Bezos here, to increase some competition.

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     Charlie Stross (cstross@wandering.shop)'s status on Friday, 17-Jan-2025 04:12:07 JST Charlie Stross

     in reply to

     • Matt Nelsen

     @zmatt You saw the lift-off video: it went up *really* slowly as it left the pad, maybe 0.1g acceleration at first. So I went for thrust:weight of 1.1, and we know how much thrust the BE-4 produces at full throttle. Hence my estimate.

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     Matt Nelsen (zmatt@beige.party)'s status on Friday, 17-Jan-2025 04:12:08 JST Matt Nelsen

     in reply to

     @cstross I like your number:

     I measured a cutaway diagram from https://thespacebucket.com/a-closer-look-at-new-glenn-its-progress/ to get a rough estimate of the length of the tanks, got a volume for a 7 meter cylinder and multiplied by density (assuming the minimum density for LNG) and get 1,600 metric tons. Add in miscellaneous (cargo, engines) and I think you're there.