Author Topic: ULA Vulcan Launch Vehicle (as announced/built) - General Discussion Thread 3  (Read 22525 times)

Offline meekGee

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The EELV is simply less interesting to most observers, and so 6 months here or there generate a lot less excitement.

There's no such thing as a less interesting EELV. Customers are interested in whatever launch vehicle best fits their need for a specific launch. They don't care how many engines it has, what color it's painted, who makes the vehicle or if it has 2 or 5 stages. They are only interested in an appropriate launch service and whatever EELV fits their needs becomes the choice.
This exchange started when someone asked why delays in the Vulcan program generate less reaction from observers, compared with slips in other nextGen schedules.

I was simply comparing what those nextGen programs were, and showing a correlation.
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Online AncientU

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The EELV is simply less interesting to most observers, and so 6 months here or there generate a lot less excitement.

They fly more interesting missions than GTO comsats or station resupply.   

Too many people are caught up in the means with the ends are more important.  I don't care how I get my packages.

When there are no winning arguments about the launch vehicle, the goal posts move to 'more interesting missions.'
Vulcan's competition will win on that field, too.
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Offline Jim

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When there are no winning arguments about the launch vehicle, the goal posts move to 'more interesting missions.'

It was never about the launch vehicles, it was always about the missions.  It has been the fan boys that have made about the launch vehicles, first it was shuttle, then it was Direct and now it is Falcon 9.

NROL, Juno, MSL, STSS Demo, X-37, MRO, SBIRS, etc are all more interesting than F9 comsat launch. 

There are parallels with train foamers and Spacex fans.
« Last Edit: 01/13/2018 08:38 PM by Jim »

Offline Chris Bergin

For Jim's next birthday I'm going to give him moderator powers for 24 hours. Then you're all running for the hills! ;D

Let's keep this on Vulcan. Some of you may realize it, but we actually cover SpaceX a bit here and have a few threads somewhere on the forum.

;D

--

One member didn't listen. That member has lost his post.

Offline Chasm

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The power pack oops and consequent silence made it quite clear that Vulcan would be affected too. So the 6 month announcement was already old news and not too interesting to observers. Centaur V however was entirely new and good reasoning.

I think the reasoning why ULA decided to eat a 6 month delay twofold.
ULA needed the Centaur V for the EELV bid. Going into the bid with a "to be developed in the future" capability for some reference orbits would be a disadvantage.
The RD-180 engine replacement obviously got delayed. The engineers might as well work on something else instead of just waiting on the next BE-4 (or even AR-1) milestone.

Offline john smith 19

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I think the reasoning why ULA decided to eat a 6 month delay twofold.
ULA needed the Centaur V for the EELV bid. Going into the bid with a "to be developed in the future" capability for some reference orbits would be a disadvantage.
I think this is the big event.  It telescopes 2 US development cycles (which was inevitable if they wanted to cover the full range of DoD orbits and payloads) into one.
Quote from: Chasm
The RD-180 engine replacement obviously got delayed. The engineers might as well work on something else instead of just waiting on the next BE-4 (or even AR-1) milestone.
Depends on the delay. My impression is AR-1 is so far behind the only way AJR has a shot is if they promise to deliver an engine that can do a full duration burn (equal to a booster stage flight to MECO) by the end of the delay (likewise for Blue).

Schedule for Vulcan deployment is everything. The faster they transition the fewer mfg lines they have to run and the faster they lower their costs.
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Offline envy887

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Too many people are caught up in the means with the ends are more important.  I don't care how I get my packages.

You have multiple competitors offering trivially cheap prices to deliver your packages. When orbital delivery has the same, the means will attract far less attention. But Vulcan ... isn't really a step in that direction. ACES is, but it's constantly 10 years away.

Online oldAtlas_Eguy

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Too many people are caught up in the means with the ends are more important.  I don't care how I get my packages.

You have multiple competitors offering trivially cheap prices to deliver your packages. When orbital delivery has the same, the means will attract far less attention. But Vulcan ... isn't really a step in that direction. ACES is, but it's constantly 10 years away.
ACES use to be 10 years away the in the future nature has now shifted to 5 years away.

Once you get to some of the features of ACES namely IVF, then the others are small incremental improvements such as in-orbit refueling which only involves tubing and valves and the most important item for in-orbit refueling the low to zero force cryo prop connectors that can be remotely released/engaged. It is this last item that is the item slowing down in-orbit cryo refueling and the general depot/distributed launch concepts.

If you have Centaur V's IVF then you have possibility to test docking and the transfer of prop between Centaur V's  without payloads or even any use of the prop that is transferred. These tests would occur on Centaur V's that the next step is disposal.

So with Centaur V and IVF that gets to with testing and incremental improvements the full ACES.

Offline Lar

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When there are no winning arguments about the launch vehicle, the goal posts move to 'more interesting missions.'

It was never about the launch vehicles, it was always about the missions.  It has been the fan boys that have made about the launch vehicles, first it was shuttle, then it was Direct and now it is Falcon 9.

NROL, Juno, MSL, STSS Demo, X-37, MRO, SBIRS, etc are all more interesting than F9 comsat launch. 

There are parallels with train foamers and Spacex fans.

I'm a train fan (but not a foamer)[1] and a SpaceX fan. (probably not a foamer)[2].

That said while individual spacecraft are interesting, and all those non comsat spacecraft are more interesting than comsats, I would suggest that what is MOST interesting is how the market is changing. And why. Because I think it is... reduction in launch cost is just starting and the changes MAY be of epic proportions.. Not the vehicles, not the payloads, the market as a whole, that's where the really interesting stuff is.

ULA and Vulcan may be too timid in their response, we'll see.  Or maybe this is just a flash in the pan and ULA will hit the sweet spot with just the right amount of change.   Not the way to bet, but maybe.

1 - by analogy, I think 3 unit and 5 unit well cars (articulated container cars) are interesting, but why railways switched to articulated container cars is far more interesting.
2 - but when Jim has mod, for those 24 hours, he may edit this to say differently
« Last Edit: 01/16/2018 04:23 PM by Lar »
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Offline spacenut

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What is the difference between ACES and the Centaur V?  Size? Engines? Common Bulkhead?  Capabilities?

Offline TrevorMonty

What is the difference between ACES and the Centaur V?  Size? Engines? Common Bulkhead?  Capabilities?
Size, ACES about 70t, Centuar V we think 40-50t. Both use 5m tanks. Don't know if IVF is being used, but suspect so. Engines unknown but most likely RL10.

Offline brickmack

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Engines are RL10. Source on 40-50 tons propellant instead of 70? Tank size looks to be pretty much identical in the renders released

Online edkyle99

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Engines are RL10. Source on 40-50 tons propellant instead of 70? Tank size looks to be pretty much identical in the renders released
It is a guesstimate, based on the performance needed to meet the EELV requirements.  The lower propellant number also seems to me likely to be able to be boosted by only two RL10s.  Since a two-engine Centaur is already being developed for Commercial Crew, it makes sense that this would still be a "Centaur", though with a fatter tank.  But these are guesses.  ULA could surprise.

 - Ed Kyle
« Last Edit: 01/16/2018 04:54 PM by edkyle99 »

Offline spacenut

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Could the Centaur V evolve into ACES?  Or are the two incompatible? 

Offline envy887

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Could the Centaur V evolve into ACES?  Or are the two incompatible?

ACES is basically a bigger Centaur, so yes. A tank stretch plus some IVF hardware upgrades (and maybe more engines) would probably be the only difference between Centaur V and ACES.

Offline spacenut

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So Centaur V would have common bulkhead and basically the same engine(s).  Seems like one BE-3U with variable thrust would be the ideal.  Thrust would depend on weight or mass plus orbit or deep space applications.  Only one engine to deal with. 

So could Centaur V be a good upper stage for SLS?  Especially for deep space probes and lunar applications? 

Online edkyle99

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So Centaur V would have common bulkhead and basically the same engine(s).  Seems like one BE-3U with variable thrust would be the ideal.  Thrust would depend on weight or mass plus orbit or deep space applications.  Only one engine to deal with. 

So could Centaur V be a good upper stage for SLS?  Especially for deep space probes and lunar applications? 
EUS is probably going to carry 120+ tonnes of propellant, a much bigger stage than Centaur 5.  I doubt BE-3U would be a good match for Centaur 5. Too much thrust, really, and probably lower specific impulse than RL10.  There's a reason that Orbital ATK dropped it from the NGL upper stage.  EUS, on the other hand, needs more thrust ...

 - Ed Kyle
« Last Edit: 01/16/2018 06:15 PM by edkyle99 »

Offline Lars-J

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Could the Centaur V evolve into ACES?  Or are the two incompatible?

ACES is basically a bigger Centaur, so yes. A tank stretch plus some IVF hardware upgrades (and maybe more engines) would probably be the only difference between Centaur V and ACES.

Right, Centaur V is basically proto-ACES. It will become ACES, once additional features are added.

Offline spacenut

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How much capability does Centaur V have over the existing Centaur they were originally going to use?

Offline brickmack

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EUS is probably going to carry 120+ tonnes of propellant, a much bigger stage than Centaur 5.

EUS also has a pretty low mass ratio, due to the separate bulkheads, huge truss structure, hypergolic RCS, etc. With a 40 ton payload (the mass SLS 1B is notionally supposed to deliver to TLI), ACES should be able to complete a delta v of 4170 m/s, while EUS can deliver the same payload mass to 5050 m/s. So its weaker, but not hugely so. And this difference will probably be mostly made up for (and maybe exceeded) by SLS's boosters/core stage having to lift ~50 tons less to the staging point, and by ACES having near-zero boiloff (EUS loses considerable propellant mass just sitting around waiting for TLI). The zero-boiloff capability also means that ACES could be used to directly insert the payload at lunar orbit, which helps a lot of Orion/DSG's performance problems. And if you allow for ACES to be refueled in LEO first (SLS only being necessary because the mass of the payload itself is too high for any other launcher even to get to LEO), it can deliver upwards of 60 tons to TLI, better than even the most optimistic targets for Block 2. Big downside though would be the small fairing diameter, so it'd depend on how volumetrically large the needed payloads actually are.

Main upside though would be cost/schedule. ACES is pretty close in external dimensions to iCPS, might be possible to fit it with much smaller upgrades to the ML, which could shave years off the schedule. And development and manufacturing cost would be covered/shared by ULA, saving probably billions on development and tens of millions per flight on hardware. Even if there was some performance loss, I think thats worth it.

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