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After a 24-second test of its engines, the New Glenn rocket is ready to fly

arstechnica.com

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Re: After a 24-second test of its engines, the New Glenn rocket is ready to fly

#111

Post by avmich »

imtringued wrote: post #64
avmich wrote: post #12

Earlier quoted context omitted.

I hope Blue Origin succeeds too, but I'm not sure which mission profiles wouldn't be served best by the Starship in comparison to other launchers. There could be some ultra-light ones, where the cost for the whole launch is less than refueling the Starship, but...

Obviously any mission that goes beyond LEO that does not aeorbrake at the destination, because that means you're expending an upper stage with aerodynamic surfaces for no reason. Also anything that does a direct TLI or TMI, because you will have to stop for in-orbit refuelling.

The cost to get to LEO dominates in most, if not all, launches, and it's relatively trivial to add a booster stage which solves additional delta-v problems while being cost preferential to alternatives.

Maybe SpaceX will make those stages, if the market would interest them. Maybe fellow companies like Impulse Space would manage those requests. Starship still looks like a probable winner in the area.

Re: After a 24-second test of its engines, the New Glenn rocket is ready to fly

#112

Post by avmich »

zizee wrote: post #62
ternnoburn wrote: post #16

Earlier quoted context omitted.

Smaller launch to a specific orbit. As an analogy, freight trains are one of the most efficient, cheapest ways to move freight. But moving my laundry to the laundromat is better served by another vehicle.

This changes if SpaceX can get full reusability working, which they have been making very steady progress towards.

Yeah, that's the main proposition Starship has for the market. Going to analogy with laundromat, you need to include the cost of single-use laundry cart and remember that your laundromat is on another end of the same asphalted road which the truck nearby can easily drive on.

Not sure at all if costs - and hassles, of course - of buying a cart are less than some change for the costs of the fuel - the truck is autonomous, of course.

Re: After a 24-second test of its engines, the New Glenn rocket is ready to fly

#113

Post by wombatpm »

OhMeadhbh wrote: post #45
wombatpm wrote: post #20

Earlier quoted context omitted.

Boeing will probably buy one of the also rams to improve their offerings

The moment SpaceX is sold to Boeing is the moment Musk doesn't get to go to Mars. And while he may never be able to have the martian colony he seems to covet, he still seems to believe he can do it, so there's zero motivation to sell. Also... Boeing? They've been having some issues lately.

I was thinking that Blue Origin was a more likely target.

Re: After a 24-second test of its engines, the New Glenn rocket is ready to fly

#114

Post by yonatan8070 »

Rebelgecko wrote: post #85
Novosell wrote: post #8

How much data do you guys reckon they gather during this 24-second window? Gigabytes? Terabytes? I imagine they have redundant sensors for every measurement, if possible. The LHC generates 1 PB/s, though it filters it down to roughly 200MB/s[0]. I wonder how this compares. 0: https://www.lhc-closer.es/taking_a_closer_look_at_lhc/0.lhc_...

Probably gigabytes. When I worked with other systems in the past we needed to upgrade our gigabit ethernet to handle the full-rate telemetry

Do you mean upgrade to gigabit or from gigabit to 2.5Gbps or 10Gbps?

Re: After a 24-second test of its engines, the New Glenn rocket is ready to fly

#115

Post by basementcat »

quotemstr wrote: post #108
basementcat wrote: post #99

Earlier quoted context omitted.

That means the customer has to buy an additional propulsion stage (plus time for integration testing and insurance in case it damages the launch vehicle, in case it becomes reusable). Also, it is not yet clear what the LEO payload capability of the vehicle is.

The cost of an expendable third stage is surely more than made up for the brute force cost savings of being able to launch 150T to LEO for the cost of fuel and a car wash.

I think it depends on the situation. It is not yet clear if 150T to LEO is real (and even if it is, you're likely sharing it with a bunch of other customers who might not want to fly with another rocket motor unless it has gone through quite a bit of vetting and paperwork; Shuttle banned the use of solid rocket motor 3rd stages after the Challenger accident) and it is not yet clear what the cost for a typical customer is going to be. Rocket engines designed to start in a vacuum are more difficult and expensive to develop and test than engines designed to operate closer to STP.

Re: After a 24-second test of its engines, the New Glenn rocket is ready to fly

#116

Post by avmich »

grecy wrote: post #103
ChuckMcM wrote: post #38

Earlier quoted context omitted.

I'm not sure I see it that way, I wonder sometimes how much of the expensive construction can be systematized into something less expensive, and how much of Starship's "cheap" construction will remain as they work harder and harder to get to their reuse and turnaround goals. My intuition is that Starship will get more expensive to make over time and New Glenn less expensive but beyond that I can't say if they would m…

> That is what had made Falcon 9 so cost effective. Mostly because they get nearly 10 flights per booster. You’re way out of date. Multiple boosters have flown over 20, a couple are at 23. https://en.m.wikipedia.org/wiki/List_of_Falcon_9_first-stage...

I guess 10 flights per booster is an average over, say, the whole time since the first booster successfully landed. In the list by this link there are ~70 boosters, and I don't think Falcons flew ~700 missions yet, so 10 flights per booster looks on average approximately correct, even though some - even quite a few - boosters flew significantly more that 10 times.

Re: After a 24-second test of its engines, the New Glenn rocket is ready to fly

#117

Post by extraduder_ire »

HPsquared wrote: post #93
dotancohen wrote: post #69

Earlier quoted context omitted.

Combustion in the chamber happens at roughly the speed of sound in the F/O mixture. I don't know what the speed of sound in gCH4 is, but it's probably within an order of magnitude of air - air at 250 bar. This is actually extremely important to model. Early F1 engines (Saturn V, not motorsport) were exploding and the engineers pretty much got lucky with the baffle design. Having a suite of sensors and then a computer…

Speed of sound also depends on the temperature (i.e. speed of the gas molecules) which is high and variable. These kinds of coupled interactions make combustion instability really hard to model in CFD hence the importance of full-scale testing.

If you solve the formulas for calculating it, the speed of sound only depends on temperature. Mostly because temperature is dependant on pressure itself.

Re: After a 24-second test of its engines, the New Glenn rocket is ready to fly

#118

Post by extraduder_ire »

OhMeadhbh wrote: post #37
zizee wrote: post #10

Earlier quoted context omitted.

Which mission profiles does Starship not make sense for?

Starship is heavy lift / heavy expense. If you want to put 1 small-sat in orbit, you don't use Starship, you use a Rocket Lab Electron. It's MUCH cheaper. Or you wait until you find 600 other small sat users who want to launch into the same / similar orbit. The talk I heard was that New Glenn was supposed to be BO's answer to Starship (or more likely Falcon Heavy) that could launch a bunch of Project Kuiper satellite…

I think the cheapest smallsat launches now available are being pushed out of the Japanese airlock on the ISS. It's very popular.

Really limits your options in terms of height/inclination but it's been popular enough that they're almost at capacity.

Re: After a 24-second test of its engines, the New Glenn rocket is ready to fly

#119

Post by baq »

DrBazza wrote: post #105
baq wrote: post #98

Earlier quoted context omitted.

I’m not sure which profiles don’t make sense unless they can’t figure out payload doors. Stage 2 reuse means you can put up 50 tons or so of stage 3 in LEO for approximately free in current payload pricing terms, it’s a crazy number. (Advertised capacity of 100-150 tons is probably pointless and/or volume-limited anyway for a third stage.)

Not all profiles end up in orbit . At this point in time, reusuability sacrifices delta-v for fuel. If you want to launch scientific missions you want to escape Earth orbit. If we're going to land on Mars, we're going to need a lot of stuff sent there first.

But it doesn’t matter if you can launch 10x the mass for the same price to LEO and light your stage 3 to get anywhere you’d like to be. Stage 3 will have enough delta v and starship’s doesn’t matter as long as it gets you to the parking orbit.

Re: After a 24-second test of its engines, the New Glenn rocket is ready to fly

#120

Post by HPsquared »

extraduder_ire wrote: post #117
HPsquared wrote: post #93

Earlier quoted context omitted.

Speed of sound also depends on the temperature (i.e. speed of the gas molecules) which is high and variable. These kinds of coupled interactions make combustion instability really hard to model in CFD hence the importance of full-scale testing.

If you solve the formulas for calculating it, the speed of sound only depends on temperature. Mostly because temperature is dependant on pressure itself.

Temperature and molecular properties.. which guess what are also highly variable in combustion! Very messy stuff. Especially when you get into the actual nitty gritty of all the intermediate chemical species involved.
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