Author Topic: ULA Vulcan Launch Vehicle (as announced/built) - General Discussion Thread 3  (Read 142378 times)

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32426
  • Cape Canaveral Spaceport
  • Liked: 11164
  • Likes Given: 331

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 »

Online 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.
« Last Edit: 01/13/2018 09:42 PM by Chris Bergin »

Offline Chasm

  • Full Member
  • ***
  • Posts: 394
  • Liked: 180
  • Likes Given: 0
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

  • Senior Member
  • *****
  • Posts: 7578
  • Everyplaceelse
  • Liked: 1169
  • Likes Given: 7826
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.
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Offline envy887

  • Senior Member
  • *****
  • Posts: 4622
  • Liked: 2539
  • Likes Given: 1395
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.

Offline oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 3479
  • Florida
  • Liked: 1887
  • Likes Given: 223
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

  • Fan boy at large
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 10642
  • Saw Gemini live on TV
  • A large LEGO storage facility ... in Michigan
  • Liked: 7508
  • Likes Given: 5277

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 »
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline spacenut

  • Senior Member
  • *****
  • Posts: 2402
  • East Alabama
  • Liked: 404
  • Likes Given: 235
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

  • Full Member
  • ****
  • Posts: 483
  • USA
  • Liked: 186
  • Likes Given: 14
Engines are RL10. Source on 40-50 tons propellant instead of 70? Tank size looks to be pretty much identical in the renders released

Offline spacenut

  • Senior Member
  • *****
  • Posts: 2402
  • East Alabama
  • Liked: 404
  • Likes Given: 235
Could the Centaur V evolve into ACES?  Or are the two incompatible? 

Offline envy887

  • Senior Member
  • *****
  • Posts: 4622
  • Liked: 2539
  • Likes Given: 1395
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

  • Senior Member
  • *****
  • Posts: 2402
  • East Alabama
  • Liked: 404
  • Likes Given: 235
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? 

Offline Lars-J

  • Senior Member
  • *****
  • Posts: 4237
  • California
  • Liked: 3658
  • Likes Given: 2253
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

  • Senior Member
  • *****
  • Posts: 2402
  • East Alabama
  • Liked: 404
  • Likes Given: 235
How much capability does Centaur V have over the existing Centaur they were originally going to use?

Offline brickmack

  • Full Member
  • ****
  • Posts: 483
  • USA
  • Liked: 186
  • Likes Given: 14
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.

Offline Sknowball

  • Member
  • Posts: 79
  • Liked: 56
  • Likes Given: 5
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

I get where 40-50 tons of prop makes sense (and respect the work you do Ed) from the perspective of meeting minimum EELV, but given that ULA has focused a lot of effort on minimize ground support changes for Vulcan does producing a squat Centaur (given that ACES was always listed as the same height as Centaur III) make sense from this perspective?  The only hard facts I have heard on Centaur V were the  various confirmations of 5.4m diameter and Jon Goff's statement regarding Centaur V based Ixion being 310m3.  Given that the Ixion mission module, according to Mike Johnson (minutes 30-37), started with the ARCTUS concept(and used it's dimensions in the initial proposal) could be fun exercise to try and figure out how much of that 310m3 is Centaur V and how much is everything else (assuming the mission module has not evolved beyond the initial proposal volume).

Quote
With up to 310 m3 habitable volume Ixion is the largest single element station since SkyLab

How do you get this number, isn't the Centaur relatively small? Some of the volume would be in the "mission module" but that looks small. Are you counting an additional cygnus-like module on top?

Hydrolox density is about 360 kg/m so the current centaur with 23 ton of propellant would have ~60 m3 of volume. 310 m3 volume would hold more than 100 tons of hydrolox.

That number is based on the Centaur V stage, and associated mission module and docking tunnel. You are correct that the Centaur III version is much smaller.

~Jon

Offline Sknowball

  • Member
  • Posts: 79
  • Liked: 56
  • Likes Given: 5
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.

I suspect MLI will also be an ACES enhancement.

Quote
1) As you observed, ACES has been updated to an inline design. Tank pressure requirements to satisfy ascent structure are similar to that required to prevent engine cavitation, thus ACES will still achieve the high mass fraction.

2) Yes, we will use a common docking interface for both the Distributed Launch propellant tanks and the B330.

3) ACES will be encapsulated in MLI (multi-layer insulation) to reduce the LH2 & LO2 boil off. MLI that can survive ascent aerodynamic forces is one of the many innovations being incorporated into ACES to enable refueling, long mission durations and numerous burns.

Bernard Kutter ULA Chief Scientist
https://www.reddit.com/r/ula/comments/76ysr9/bigelow_aerospace_and_united_launch_alliance/doova5k/

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 7578
  • Everyplaceelse
  • Liked: 1169
  • Likes Given: 7826

EUS also has a pretty low mass ratio, due to the separate bulkheads, huge truss structure, hypergolic RCS, etc.
IIRC SLS is going to test a version of IVF.

Does anyone know if that will be on the first flight? If so it would do a lot to raise the TRL level for fitting it on Centaur 5 sooner rather than later.

I think IVF is a major enabler of lower internal costs for ULA (and it's a really neat hack which should be applicable to nearly any system, given how Titan did its tank pressurization).  It also opens up the options for using a ULA US for trajectory changes, post Earth departure
« Last Edit: 01/16/2018 11:23 PM by john smith 19 »
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Offline Sknowball

  • Member
  • Posts: 79
  • Liked: 56
  • Likes Given: 5

EUS also has a pretty low mass ratio, due to the separate bulkheads, huge truss structure, hypergolic RCS, etc.
IIRC SLS is going to test a version of IVF.

Does anyone know if that will be on the first flight? If so it would do a lot to raise the TRL level for fitting it on Centaur 5 sooner rather than later.

I think IVF is a major enabler of lower internal costs for ULA (and it's a really neat hack which should be applicable to nearly any system, given how Titan did its tank pressurization).  It also opens up the options for using a ULA US for trajectory changes, post Earth departure

The IVF study for SLS was on integrating it into the EUS(so EM-2 or later), last update on this was at the NASA NAC TI&E meeting in July when the study was reported as complete.  Slide 15 https://www.nasa.gov/sites/default/files/atoms/files/nac_july2017_flores_tdm_irma_tagged.pdf

Outside of this document a NTRS report was published on numerical modeling of the IVF system in October
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170008954.pdf

I get the feeling that as we have not heard anything since the study was completed that they opted not to included it in EUS.
« Last Edit: 01/17/2018 12:16 AM by Sknowball »

Tags: