Author Topic: Will be the Vulcan the more reliable rocket of ULA in her history? (Read 22925 times)

Tywin · « **on:** 05/20/2022 09:48 am »

What do you think?

DreamyPickle · « **Reply #1 on:** 05/20/2022 12:33 pm »

I don't think it will be launched enough to match the record of Atlas V.

SweetWater · « **Reply #2 on:** 05/20/2022 12:55 pm »

I voted no, but only because Atlas V will be a *very* tough act to follow. 93 total launches to date, 92 of which were successful with 1 partial failure that left the payloads a bit low but which, IIRC, the NRO still considered a successful mission. A launch history like that is a remarkable achievement.

Eric Hedman · « **Reply #3 on:** 05/20/2022 01:14 pm »

I voted maybe. At this stage there is no way of telling. One complete failure of Vulcan would make it impossible to match the Atlas V record. They have a new engine from a new supplier. If they get past the first few launches okay, the chances go up.

Kaputnik · « **Reply #4 on:** 05/22/2022 10:59 am »

Delta IV has had a 100% success rate as a ULA vehicle.
So I voted no, because at best Vulcan could equal that.

Jim · « **Reply #5 on:** 05/22/2022 01:21 pm »

Quote from: Kaputnik on 05/22/2022 10:59 am

Delta IV has had a 100% success rate as a ULA vehicle.
So I voted no, because at best Vulcan could equal that.

See Heavy Demo

DanClemmensen · « **Reply #6 on:** 05/22/2022 01:53 pm »

Computing rocket reliability is a complex issue and is subject to interpretation. Which is more reliable, a rocket that has one launch that was a success, or a rocket that has launched 100 times with only one failure? This was discussed extensively at:
https://forum.nasaspaceflight.com/index.php?topic=39928.20
Which includes links to academic papers.

Atlas V has 93 launches so far. All of them were successes, but one had a minor problem that one of its two payloads was unable to recover from. How do you account for that? In any event that's a hard number to beat. Unless something unexpected happens, Atlas V will finally retire after 116 launches. It is unclear that Vulcan will ever fly 116 times.

spacenut · « **Reply #7 on:** 05/22/2022 01:58 pm »

I voted no because of the unknowns of an unflown rocket. BE-4 may be a problem until bugs are figured out.

deltaV · « **Reply #8 on:** 05/22/2022 07:41 pm »

My guess is that getting ULA's costs down to the same ballpark as SpaceX will come at the expense of reliability coming down to the same ballpark as SpaceX. I therefore expect Vulcan's reliability to be adequate but not as good as ULA's previous launchers.

sdsds · « **Reply #9 on:** 05/22/2022 08:20 pm »

No. Complexity.

DanClemmensen · « **Reply #10 on:** 05/22/2022 08:35 pm »

Quote from: deltaV on 05/22/2022 07:41 pm

My guess is that getting ULA's costs down to the same ballpark as SpaceX will come at the expense of reliability coming down to the same ballpark as SpaceX. I therefore expect Vulcan's reliability to be adequate but not as good as ULA's previous launchers.

Falcon 9 Block 5 has had 101 successful launches and no failures.
Atlas V has had 93 successful launches and no complete failures.

high road · « **Reply #11 on:** 05/29/2022 04:58 pm »

I voted no because 'in the history of ULA', both Atlas and Delta have had 100% success rate, so Vulcan can only be as reliable, at best.

Robert_the_Doll · « **Reply #12 on:** 05/29/2022 06:17 pm »

Quote from: SweetWater on 05/20/2022 12:55 pm

I voted no, but only because Atlas V will be a *very* tough act to follow. 93 total launches to date, 92 of which were successful with 1 partial failure that left the payloads a bit low but which, IIRC, the NRO still considered a successful mission. A launch history like that is a remarkable achievement.

Technically, two partial failures. The 15 June 2007 NROL-30 launch that you mention and then the 23 March 2016 Cygnus OA-6 mission that saw the RD-180 on the first stage shut down 5 seconds early, but fortunately the Centaur III 2nd stage was able to compensate. But the OA-6 mission was right on the edge of failure had the RD-180 shut down just a few seconds sooner.

butters · « **Reply #13 on:** 05/29/2022 06:57 pm »

Kuiper will push ULA to sustain higher flight rates than they've handled to date. If it was just the spectacular, ever-slipping, never-ready payloads of NSSL, then they'd have much more time on their hands to make sure every i is beautifully dotted.

russianhalo117 · « **Reply #14 on:** 05/29/2022 07:42 pm »

Quote from: butters on 05/29/2022 06:57 pm

Kuiper will push ULA to sustain higher flight rates than they've handled to date. If it was just the spectacular, ever-slipping, never-ready payloads of NSSL, then they'd have much more time on their hands to make sure every i is beautifully dotted.

The biggest problem with the DIV family was the actual annual flight rate numbers which resulted in continual GSE issues due to lack of use that the higher flight rate of Atlas V rarely suffered from. Vulcan will have a higher flight rate because of the legacy DII/DIII/DIV and AV families flight rates and payload classes merging into the unified singular VC product family (the upper end of the DII/DIII payload class configurations transfer to the bottom end of the VC payload class configurations).

AmigaClone · « **Reply #15 on:** 06/10/2022 08:43 am »

For a while I can see the Vulcan-Centaur being the most reliable rocket ULA has developed.

Two comments:
At best, the VC can match the reliability of the retired Delta II and single stick Delta IV, neither of which had a failed launch when launched by ULA.

How well VC does compared to the Delta Heavy and the Atlas V will depend not only on it's own reliability, but also on the future reliability of those two retiring rockets.

lightleviathan · « **Reply #16 on:** 01/14/2023 06:06 pm »

Vulcan has the potential to be, but to do that, it has to survive it's first flight, which I'm not sure will happen.

Proponent · « **Reply #17 on:** 01/15/2023 03:42 pm »

Though I expect Vulcan to become operational, I would hazard a guess that, because if its high cost, it will never fly enough to statistically demonstrate a reliability higher than the best its predecessors.

FishInferno · « **Reply #18 on:** 01/15/2023 03:53 pm »

Quote from: deltaV on 05/22/2022 07:41 pm

My guess is that getting ULA's costs down to the same ballpark as SpaceX will come at the expense of reliability coming down to the same ballpark as SpaceX. I therefore expect Vulcan's reliability to be adequate but not as good as ULA's previous launchers.

Emphasis mine.

What do you mean by this? If my info is correct, SpaceX has succesfully launched over 150 times since the AMOS-6 failure, far more than the Atlas V has launched in its lifetime.

edkyle99 · « **Reply #19 on:** 01/15/2023 04:30 pm »

Quote from: FishInferno on 01/15/2023 03:53 pm

Quote from: deltaV on 05/22/2022 07:41 pm
My guess is that getting ULA's costs down to the same ballpark as SpaceX will come at the expense of reliability coming down to the same ballpark as SpaceX. I therefore expect Vulcan's reliability to be adequate but not as good as ULA's previous launchers.

Emphasis mine.

What do you mean by this? If my info is correct, SpaceX has succesfully launched over 150 times since the AMOS-6 failure, far more than the Atlas V has launched in its lifetime.

Falcon 9 v1.2 has logged 175 successful orbital flights as of January 15, 2023, not including the ground test failure and not including the suborbital abort test flight.

As for Vulcan, what it has going for it is ULA's proven processes, which have supported the company's very successful launch results. The human factor is vital to steady success. So is contractor configuration control. Vulcan's question marks at first will be, in my mind, the use of so many all-new systems. Atlas 5, for example, used Centaur little-changed from before and RD-180 was based on proven propulsion. Vulcan will start with new staged-combustion BE-4, a new propellant combination, big new unproven solid motors, and a brand-new upper stage. Only the Centaur 5 engines have a long lineage.

On paper, Falcon 9 should beat Vulcan in reliability over the long run because it has fewer separation events, because it uses gas generator engines, and because it uses common propellants on both stages. On paper.

- Ed Kyle

Poll

Will be the Vulcan the more reliable rocket of ULA in her history?

Author Topic: Will be the Vulcan the more reliable rocket of ULA in her history? (Read 22925 times)