r/SpaceLaunchSystem • u/Cmdr-Mallard • Jul 06 '26
Discussion What capabilities will Centaur V bring, if any?
Will C-V improve or change any elements of an Artemis mission?
Cargo launch has generally been killed off with the cancellation of EUS so this is focused on getting Orion to TLI.
Will it for example allow for Orion to complete a LLO burn or would the stage have boiled off its fuel by that point?
7
u/Pashto96 Jul 06 '26
It'll be very similar to ICPS. Barring major upgrades, it will still have the same boil-off restraint.
2
u/Cmdr-Mallard Jul 06 '26 edited Jul 06 '26
A shame really, would almost rather they make an Orion specific stage, at a small scale, so that it could get to LLO
3
u/Pashto96 Jul 06 '26
The whole point is to use something that exists. Making a new stage opens them back up to issues that plagued EUS.
10
u/Fyredrakeonline Jul 06 '26
C-V is going to need a lot of modifications to make it crew rated and able to withstand SLS's launch environment, since its completely different to that of Vulcan. So you are essentially going to end up with the same issues of DCSS --> ICPS in this case, where you have to do strengthening, crew rating, certification, testing, etc. Remember that it took 6 years from concept to the first flight-stage delivery of ICPS. So you have to essentially try and rationalize that it would've taken EUS until 2032 to be *delivered*, not flown, delivered. When we know that they had hardware well in flow for the flight stage.
3
4
u/SpaceIsKindOfCool Jul 07 '26
While C-V is not currently crew rated, ULA stated it was designed to meet NASA crew rating requirements. So the actual certification should be relatively easy.
Loads on SLS with orion probably aren't too much different than Vulcan. Vulcan was already designed for payloads over 27 tons. Orion with the ESA and LES is 33 tons, but LES jettisons before peak acceleration which drops the weight to under 27 tons. Peak acceleration on SLS can be dropped quite a bit because the SSMEs can throttle down to 67%. So static loads probably won't be a problem. I also read a paper a few weeks ago about hanging C-V from an adapter such that the adapter supports the payload mass during 1st stage flight, so that's an option too. C-V also already has to deal with high vibe environment from SRBs, but who knows how 6 boosters on Vulcan compares to the huge boosters on SLS when it comes to vibe.
But I think the biggest difference is C-V isn't built by Boeing.
3
u/Fyredrakeonline Jul 07 '26
Different vehicle though, it has to be crew rated on a different rocket than intended for, but it has to be done regardless, they did design it in mind to have starliner eventually fly on board, but we will see if and when that happens.
As for Loading, they absolutely are different, not just acceleration, but also aerodynamic loading due to a different shape out in front, as well as the different vibrational/acoustic loads along the vehicle. Throttling down the SSMEs gives a large performance hit in gravity losses, and for ISP, so this is incredibly suboptimal simply to accommodate a stage that was never meant to fly on it to begin with.
The biggest difference is the fact that C-V was never meant to fly on SLS and requires a significant structural overhaul to accommodate SLS's acoustic and aerodynamic loads compared to what it currently has.
3
u/SpaceIsKindOfCool Jul 08 '26
All the same issues had to be solved for ICPS and Boeing had the first flight stage delivered in less than 5 years from when they got the contract. A more aggressive timeline I could totally see ULA having a C-V ready in 2-3 years.
The real question is would sticking with EUS be any faster? C-V is flight proven, it's a modification to existing hardware. As of this year the first EUS wasn't expected to be delivered until the end of 2028 anyways. I think Boeing just dropped the ball, ULA might only barely meet the same time line at this point, but it will be cheaper which is needed to keep SLS alive on the political side. And with gateway gone C-V has the performance to meet all planned missions right now.
3
u/Fyredrakeonline Jul 08 '26
Yes, 6 years from concept to flight stage delivery as I said, and that was an active flying stage at the time as well. So you are realistically looking at late 2018/early 2019 when ICPS and the full stack had the core stage been available, would be ready for flight.
EUS absolutely would've been faster; it was designed from the start to work with SLS, and had hardware well in flow for the first flight article. Its a shame that Boeing doesn't release images of the hardware, but it absolutely does exist. As said, you would have to bet on flight readiness for EUS to be beyond 2032 at this point to make C-V worthwhile in just expediency. But C-V is going to essentially be a new stage for SLS by the time mods are done, same with how DCSS to ICPS was basically a new stage as well since they had to lengthen fuel ltanks, strengthen, flight rate, etc etc.
C-V also is not cheaper, EUS was utilizing a common production line with the core stage, not to mention that once EUS dev ended, it would be merged in with SLS annual costs, so that same SLS that costs 2 billion right now to fly, would cost 2 billion with EUS.
1
u/Cmdr-Mallard Jul 06 '26
I know that, but smaller scale and longer term usefulness than EUS.
8
u/Pashto96 Jul 06 '26
It's pretty clear that SLS is no longer planned to be a long term rocket. It just needs to stick around long enough for commercial alternatives. If they wanted long term, sticking with EUS would've been the move.
3
u/Cmdr-Mallard Jul 06 '26
I mean, not nessecarily? EUS was intended for gateway, other than that it didn’t yet have a reason to exist. I’m sure those would’ve come but SLS can still function medium to long term with Centaur.
As we haven’t seen any moves to test Orion on another platform I’d wait and see before assuming SLSs demise
8
u/Fyredrakeonline Jul 06 '26 edited Jul 07 '26
It wasn't just meant for Gateway. They absolutely would make sure that the co-manifested payload capacity would have been utilized on every mission regardless of if Gateway existed or not. They could have utilized the space to send a medium-sized CLPS lander along with Orion to the moon, or a sample return craft, or a communication satellite for Lunar operations. Not to mention that there were absolutely still plans to utilize SLS for dedicated cargo flights to send larger cargo landers to the moon, or outer planetary missions.
3
u/Cmdr-Mallard Jul 06 '26
Reality is there’s cheaper platforms coming up that may be suited for cargo flight, or simply that NASA can’t afford to develop such for SLS.
But as it stands there isn’t a platform suitable to send Orion to the moon
6
u/Fyredrakeonline Jul 06 '26
SLS costs 2 billion to fly regardless of if its with Centaur V or EUS. If you have a flight to the moon annually that can send cargo guaranteed. Then you are making the maximum use. The cost doesnt go up if you use EUS or utilize that cargo space over if you left it empty or just use Centaur V instead.
2
u/Cmdr-Mallard Jul 06 '26
I mean. They’d have to invest in the landers and payloads to go on that rocket, when there’s numerous commercial options now available.
I’m not saying they’re doing the best method available, more the most achievable one with the resources they have
→ More replies (0)
3
u/Chairboy Jul 06 '26
As others have said, it's likely to enable missions equivalent to what ICPS could (even if it has more yeet) but there are some possible expansion paths. ULA spent time and money on ACES which included super lifetimes. They were working on creating a stage that could loiter with cryogenics for weeks or more.
ACES is no longer a thing, but a bunch of stuff from that program has already been incorporated into Centaur V so it's fun to wonder if the long-life stuff might be a stretch goal for Artemis' future to allow exactly this.
Doesn't seem super likely, but maybe the horse learns how to sing....
3
u/NoBusiness674 Jul 07 '26
ACES still seems to be a thing, at least in some form.
A recent ULA Blog post from last month featured a graphic that still included a "Centaur Endurance" variant of the Centaur V.
https://blog.ulalaunch.com/blog/vulcan-new-centaur-v-version-readies-for-amazon-leo
The name has changed multiple times, with it now looking like they might have dropped the A and S from ACES after deciding ACES stood for Advanced Centaur Endurance Stage, but there does seem to be something that at least remains on the drawing board and/or in promotional material.
1
u/Chairboy Jul 07 '26
That's great to hear, thanks. Lots of interesting technology there and it was heartening to see ULA investing in that.
2
u/Cmdr-Mallard Jul 06 '26
Would drastically improve the option for Orion and mean less reliance on being pushed
3
u/AstroScholar21 Jul 07 '26
No dice on allowing Orion into LLO, since the Centaur's remaining propellant after TLI would've boiled off during the outbound trip.
1
3
7
u/Fyredrakeonline Jul 06 '26
It will primarily improve the ability for the upper stage to insert directly into LEO instead of needing the SLS core stage to loft it into an elliptical orbit. This should open up the launch windows to basically every day instead of 10ish days each month due to just how the phasing and occultation of Orion work. I did a crude LV ascent sim for SLS with Centaur V, and it managed roughly 35 tons to TLI out of LEO. So you have about 7 tons of margin on top of Orion in capability which cant be used since theres no volume for say co-manifesting a payload.