Poll

Which methalox launcher will reach orbit first?

New Glenn
1 (1.3%)
Starship
39 (52%)
Vulcan
31 (41.3%)
Zhuque-2
4 (5.3%)
other
0 (0%)

Total Members Voted: 75

Voting closed: 03/21/2021 06:36 pm


Author Topic: Which methalox launcher will reach orbit first?  (Read 18641 times)

Offline chopsticks

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Re: Which methalox launcher will reach orbit first?
« Reply #40 on: 07/12/2023 05:28 am »
Congrats China! For Zhuque, it truly does settle this topic since even if Vulcan would have made orbit, only the booster is methalox. In contrast, both stages on Zhuque were methalox.

Hopefully some decent footage will be released yet.
« Last Edit: 07/12/2023 05:29 am by chopsticks »

Offline First Mate Rummey

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Online eeergo

Re: Which methalox launcher will reach orbit first?
« Reply #42 on: 07/12/2023 08:43 am »
I'm betting Vulcan will follow.

I would not bet on it after this: https://www.cnbc.com/2023/07/11/jeff-bezos-blue-origin-be-4-rocket-engine-explodes-during-testing.html

I would. Check out even the most pessimistic takes on this issue. Further, it's not like the other "close" contender has any shortage of engine failures.
-DaviD-

Offline rfdesigner

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Re: Which methalox launcher will reach orbit first?
« Reply #43 on: 07/12/2023 09:32 am »
I'm betting Vulcan will follow.

I would not bet on it after this: https://www.cnbc.com/2023/07/11/jeff-bezos-blue-origin-be-4-rocket-engine-explodes-during-testing.html


I would. Check out even the most pessimistic takes on this issue. Further, it's not like the other "close" contender has any shortage of engine failures.


The reason for the failures is all.

If it failed because they were doing test to death, then it's not a failure (however it failed at 10 seconds, which suggest it's not a test to death)

If it failed because they were pushing the envelope, then it's not a failure (however this was apparently a deliverable unit, you don't push the envelope on deliverables)

If it failed a production qualification test, then that is unfortunate/bad news but only if the supply of engines coming off the line is very low.  If you're making 10 a week with a delivery schedule that requires 8 per week and you blow one engine a week, that isn't bad news, that just means you have a 90% yield.

Additionally how close to reality is the production test?.. if BOs production test calls for a 10% overstress, while others only call for 5% overstress then they ought to lose fewer engines in flight than competitors.

I can't answer those last two.

My experience is with electronics.. we get production failures that don't necessarily mean bad design, or even bad manufacture, it's always a complex picture.  The biggest issue with most of these rockets is the low volume of manufacture, which means it's very hard to get good production stats i.e. I never regard any averages or standard deviations as meaningful until a bare minimum of 30 units.. ideally over 100 units.  I'm not sure how many final-spec-engines they've made (note, prototypes don't count here).  I've had one product go from 90% yield to 5% yield after 150,000 units because of batch to batch variation, we fixed that one and got a 60% yield on that batch.

My gut feel is the engine blew due to low production volume at this stage..   the question is what yield are they getting?.. do they have the capacity to overbuild to deal with that?

That answer could well be a yes, in which case the bet would still be on.

Online Yggdrasill

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Re: Which methalox launcher will reach orbit first?
« Reply #44 on: 07/12/2023 11:01 am »
I'm betting Starship will be next. Next flight maybe August.

Raptor has had some troubles, but Starship only needs around 80%* of the engines to actually work. Vulcan needs 100%.

* That's even conservative, for the initial flight tests. Without payload, Starship could almost work as an SSTO. As long as Super Heavy makes it to stage separation (at some velocity and altitude), getting to (quasi-)orbit should be achievable. First flight could have made it if it hadn't lost TVC.
« Last Edit: 07/12/2023 11:27 am by Yggdrasill »

Online eeergo

Re: Which methalox launcher will reach orbit first?
« Reply #45 on: 01/08/2024 07:56 am »
Second methalox rocket has now successfully completed its first launch - happy new year! Turns out it's Vulcan, and has performed flawlessly sending a payload to the Moon, not just any orbit. Yet again, the difference between expectations in the poll and reality is stark. Of course, ZQ-2 has also completed another successful flight in the meantime.


My bet from back in July stood strong. Not ready to rehash a new one, since the status of New Glenn is quite nebulous at this time, but I wouldn't write off the possibility of it being the next methalox to reach orbit next, given the status of BE-4 demonstrated by today's flight.
« Last Edit: 01/08/2024 07:59 am by eeergo »
-DaviD-

 

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