Author Topic: Antares General Discussion Thread  (Read 363191 times)

Offline chrisking0997

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Re: Antares General Discussion Thread
« Reply #360 on: 12/10/2014 08:40 pm »
Im a little lost on this.  Is this just a case of swapping to a new engine, with minor changes to allow that, or is there significant redesign needed for the change?  A year seems like a pretty fast turnaround.
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Re: Antares General Discussion Thread
« Reply #361 on: 12/10/2014 08:54 pm »
Im a little lost on this.  Is this just a case of swapping to a new engine, with minor changes to allow that, or is there significant redesign needed for the change?  A year seems like a pretty fast turnaround.

RD-193 was specifically designed to replace the NK-33, so it should be relatively straightforward compared to other stage re-engine proposals. But one year does seem a little optimistic given Orbital's limited in-house expertise with liquid stages.

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Re: Antares General Discussion Thread
« Reply #362 on: 12/10/2014 09:16 pm »
The RD-170 design may be an improvement, but is there any evidence the NK-33 design is bad? 

On the NK-33, the main LOX pump is fed by an inducer pump which is driven by pressurized LOX, forming a positive feedback loop which could *potentially* amplify a transient toward cavitation in the main pump, as the performance of the inducer pump is degraded by the same condition it is supposed to prevent.

Offline rayleighscatter

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Re: Antares General Discussion Thread
« Reply #363 on: 12/10/2014 09:39 pm »
Im a little lost on this.  Is this just a case of swapping to a new engine, with minor changes to allow that, or is there significant redesign needed for the change?  A year seems like a pretty fast turnaround.
Orbital knew they were going to have to get a new engine before ORB-3 happened. I'm guessing they already had a start on the replacement program.

Offline Prober

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Re: Antares General Discussion Thread
« Reply #364 on: 12/10/2014 10:32 pm »
Hard to believe that the new engines are nearly on their way, set to arrive in just a few months if the announced schedule is right, and yet Orbital still has not announced which engines or who will manufacture/deliver them.  Meanwhile, ULA has already announced its engine choice for something that won't fly until 2019!

I wonder why.

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Factor in they are a 1) public company 2) in the middle of the merger.

Any headlines about "Russian engines" at this point in time is a stock drop.
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Offline russianhalo117

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Re: Antares General Discussion Thread
« Reply #365 on: 12/10/2014 10:40 pm »
Hard to believe that the new engines are nearly on their way, set to arrive in just a few months if the announced schedule is right, and yet Orbital still has not announced which engines or who will manufacture/deliver them.  Meanwhile, ULA has already announced its engine choice for something that won't fly until 2019!

I wonder why.

 - Ed Kyle
It is my understanding that both enigines are being sent to USA for final Evaluation testing and flight engines will also be fired at Stennis for hotfire testing. Not sure if AJ-26 stands will be used for this.

Offline Mader Levap

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Re: Antares General Discussion Thread
« Reply #366 on: 12/10/2014 11:20 pm »
Atlas V, the most expensive option but also likely the most reliable option.  I wonder why Falcon 9 didn't make the cut.  Maybe it can't lift as much as claimed, or costs more than claimed?
There could also have been pressure (internal & external) to not put all CRS eggs on one launcher.
Or SpaceX could not fit it in their busy schedule.

Or any combination of above with any degree.
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Offline baldusi

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Re: Antares General Discussion Thread
« Reply #367 on: 12/10/2014 11:47 pm »
Atlas V, the most expensive option but also likely the most reliable option.  I wonder why Falcon 9 didn't make the cut.  Maybe it can't lift as much as claimed, or costs more than claimed?
There could also have been pressure (internal & external) to not put all CRS eggs on one launcher.
Or SpaceX could not fit it in their busy schedule.

Or any combination of above with any degree.
Or ULA did put a competitive bid. There are contractors that help you go really over budget, like IBM, simply by saying yes to every requirement and then passing the bill, no matter how wasteful it is. But Orbital has to foot the bill and know exactly what to do and how to integrate.
« Last Edit: 12/10/2014 11:51 pm by baldusi »

Offline arachnitect

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Re: Antares General Discussion Thread
« Reply #368 on: 12/11/2014 12:19 am »
Atlas V, the most expensive option but also likely the most reliable option.  I wonder why Falcon 9 didn't make the cut.  Maybe it can't lift as much as claimed, or costs more than claimed?

 - Ed Kyle

CRS II is on the line; maybe ULA gave Orbital schedule/upmass assurances that Spacex couldn't match. Saving $40M(?) on one launch wouldn't be too smart if it ended up costing Orbital their shot at another multibillion dollar contract.

Or maybe ULA threw in purchase options on RD-180s to sweeten the deal.

Offline LouScheffer

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Re: Antares General Discussion Thread
« Reply #369 on: 12/11/2014 12:49 am »
Atlas V, the most expensive option but also likely the most reliable option.  I wonder why Falcon 9 didn't make the cut.  Maybe it can't lift as much as claimed, or costs more than claimed?

 - Ed Kyle

There could also have been pressure (internal & external) to not put all CRS eggs on one launcher.
I could very easily see Orbital's board looking at the impact of another failure, and deciding for the most reliable option,  regardless of cost.  The cost difference between launchers can only be a few tens of millions, but the follow-on contract could be worth billions.  There's never a good time for a failure, but there are particularly bad times, and this is one.

Offline Lee Jay

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Re: Antares General Discussion Thread
« Reply #370 on: 12/11/2014 12:53 am »
It could also be that Atlas V's lift capacity allowed them to drop the final flight, whereas Falcon 9 would have come up short and required that final flight.

Offline Will

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Re: Antares General Discussion Thread
« Reply #371 on: 12/11/2014 01:31 am »
Atlas V, the most expensive option but also likely the most reliable option.  I wonder why Falcon 9 didn't make the cut.  Maybe it can't lift as much as claimed, or costs more than claimed?
There could also have been pressure (internal & external) to not put all CRS eggs on one launcher.
Or SpaceX could not fit it in their busy schedule.

Or any combination of above with any degree.

I suspect that the tight SpaceX manifest was a factor, and a disinclination of SpaceX to assist a company they are competing with directly.

Offline WindnWar

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Re: Antares General Discussion Thread
« Reply #372 on: 12/11/2014 02:27 am »
It could also be that Atlas V's lift capacity allowed them to drop the final flight, whereas Falcon 9 would have come up short and required that final flight.

Unless the specs are way off, Falcon 9 should have almost 3,000 kilos more payload to LEO versus a 401, so I seriously doubt its a capacity issue and given the fairing its definitely not a space issue. I would imagine it has more to do with a schedule issue. 

Offline nimbostratus

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Re: Antares General Discussion Thread
« Reply #373 on: 12/11/2014 03:12 am »
Atlas V, the most expensive option but also likely the most reliable option.  I wonder why Falcon 9 didn't make the cut.  Maybe it can't lift as much as claimed, or costs more than claimed?
There could also have been pressure (internal & external) to not put all CRS eggs on one launcher.
Or SpaceX could not fit it in their busy schedule.

Or any combination of above with any degree.

I suspect that the tight SpaceX manifest was a factor, and a disinclination of SpaceX to assist a company they are competing with directly.

Competitor?
Spacex ensures OSC make a profit for gap filler launches, while Atlas V costs more than Antares and OSC will hardly make a profit.
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Offline nimbostratus

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Re: Antares General Discussion Thread
« Reply #374 on: 12/11/2014 03:37 am »
Hi guys, how about New LV adopts BE-4 too, sharing engines with ULA and BO, to further reduce to cost?

One BE-4 offers a lower thrust than 2 NK-33, but has higher Isp, so seems to offer a similar delivery capacity with current Antares with verniers(to be developed too).
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Offline Will

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Re: Antares General Discussion Thread
« Reply #375 on: 12/11/2014 04:11 am »
Atlas V, the most expensive option but also likely the most reliable option.  I wonder why Falcon 9 didn't make the cut.  Maybe it can't lift as much as claimed, or costs more than claimed?
There could also have been pressure (internal & external) to not put all CRS eggs on one launcher.
Or SpaceX could not fit it in their busy schedule.

Or any combination of above with any degree.

I suspect that the tight SpaceX manifest was a factor, and a disinclination of SpaceX to assist a company they are competing with directly.

Competitor?
Spacex ensures OSC make a profit for gap filler launches, while Atlas V costs more than Antares and OSC will hardly make a profit.

But SpaceX has no reason to keep OSC alive. The  best outcome for SpaceX is for OSC to go bankrupt ASAP.

Offline arachnitect

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Re: Antares General Discussion Thread
« Reply #376 on: 12/11/2014 04:29 am »
Atlas V, the most expensive option but also likely the most reliable option.  I wonder why Falcon 9 didn't make the cut.  Maybe it can't lift as much as claimed, or costs more than claimed?
There could also have been pressure (internal & external) to not put all CRS eggs on one launcher.
Or SpaceX could not fit it in their busy schedule.

Or any combination of above with any degree.

I suspect that the tight SpaceX manifest was a factor, and a disinclination of SpaceX to assist a company they are competing with directly.

Competitor?
Spacex ensures OSC make a profit for gap filler launches, while Atlas V costs more than Antares and OSC will hardly make a profit.

But SpaceX has no reason to keep OSC alive. The  best outcome for SpaceX is for OSC to go bankrupt ASAP.

Complementary businesses, don't really compete much. Even their CRS products don't really compete directly.

Offline arachnitect

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Re: Antares General Discussion Thread
« Reply #377 on: 12/11/2014 04:32 am »
Hi guys, how about New LV adopts BE-4 too, sharing engines with ULA and BO, to further reduce to cost?

One BE-4 offers a lower thrust than 2 NK-33, but has higher Isp, so seems to offer a similar delivery capacity with current Antares with verniers(to be developed too).

Goldilocks problem: 1x BE-4 is too little thrust, 2x BE-4 is too much. Either way means big first stage changes.

OSC needs a new engine yesterday. BE-4 won't be ready in time.

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Re: Antares General Discussion Thread
« Reply #378 on: 12/11/2014 04:51 am »
It is my understanding that both enigines are being sent to USA for final Evaluation testing and flight engines will also be fired at Stennis for hotfire testing. Not sure if AJ-26 stands will be used for this.

Evaluation testing by ... whom? AJR presumably could use the same stand as was previously used for AJ-26. Does anyone else have an appropriate test stand (and test expertise) available?
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Offline nimbostratus

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Re: Antares General Discussion Thread
« Reply #379 on: 12/11/2014 04:52 am »
Hi guys, how about New LV adopts BE-4 too, sharing engines with ULA and BO, to further reduce to cost?

One BE-4 offers a lower thrust than 2 NK-33, but has higher Isp, so seems to offer a similar delivery capacity with current Antares with verniers(to be developed too).

Goldilocks problem: 1x BE-4 is too little thrust, 2x BE-4 is too much. Either way means big first stage changes.

OSC needs a new engine yesterday. BE-4 won't be ready in time.
What matters is not only thrust, but also Isp, a LV with lower thrust and lower liftoff weight can also deliver the same payload, just as the case of Atlas V and Delta IV(of course, it is a extreme case).
Also, perhaps verniers are needed(not neccesary if rcs is available).
And still more, the verniers can be developed into second stage engine, which means even higher delivery capacity.
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