Jump to content

'Vulcan' - ULA's New Rocket


Woopert

Recommended Posts

Engines are typically the most expensive part..

But I don't think it'll be much better than the SSMEs. Re certifying them cost a lot. Considering they had to pretty much rebuild them.

That is the question. SSMEs are 30 something odd years old technology now. So I guess for both SpaceX and Blue Earth the question is how much have they advanced the technology?

Link to comment
Share on other sites

How beneficial are these large fairings? I don't really see the point of them. Better aerodynamic stability maybe?
The Centaur stage goes underneath them as well. The fairing protects the balloon tanks.
Link to comment
Share on other sites

That is the question. SSMEs are 30 something odd years old technology now. So I guess for both SpaceX and Blue Earth the question is how much have they advanced the technology?

If it's heavily simplified, maybe. MAYBE.

- - - Updated - - -

RS-25s (SSMEs) are very good yet today. They also have a high ISP. 450 in vacuum or something like that.

They're good engines, no one is arguing against that. But they weren't good for reuse. Not by a longshot.

Link to comment
Share on other sites

The Centaur stage goes underneath them as well. The fairing protects the balloon tanks.

Yes, for the balloon tanks it makes sense but I don't know why it's needed to cover the Centaur. The Atlas V has two versions. Maybe StrandedonEarth is right but I have to look it up.

Edited by Reddragon
Link to comment
Share on other sites

The larger (5m) fairings cover the centaur for structural and aerodynamic reasons, which are effectively the same thing in this context; they allow forces to be transferred directly to the booster rather than through centaur. The fairings are the size they are to fit larger payloads, such as most modern communications satellites, and the 4m fairing that doesn't cover centaur will be/is used when possible due to it's lower mass.

Link to comment
Share on other sites

Elon Musk be really happy about this announcement. The beauty of commercial introduction to spaceflight is that it is now forcing the industry to revaluate the status quo. Efficiency, Reusability, low cost, all will bring down the overall cost of spaceflight and maybe one day in my life time space travel will be as regular or almost as regular as commercial airlines. You can say a lot about Elon Musk but what he has done forced the industry make changes. If they land on that barge tomorrow and he lowers his cost even more there is no telling what will be next for the rest of the space industry. If he can further undercut all they other major launch vehicles either they will need to change or SpaceX will be the only way to get to and from space. I liken to PanAm, TWA, and the enormous airlines of the "golden age" of flight. I really hope we are almost there for rocketry.

Link to comment
Share on other sites

RS-25s (SSMEs) are very good yet today. They also have a high ISP. 450 in vacuum or something like that.

Yes but they was also used hard (red lined) during shuttle launch.

If you want to reuse engines you don't run them at 105% max effect

Link to comment
Share on other sites

Yes but they was also used hard (red lined) during shuttle launch.

If you want to reuse engines you don't run them at 105% max effect

I thought the entire "105%" thing was more of a case of design improvements meaning they could get more power out of the engines, and rather than redefine what 100% was they opted to simply use numbers greater than 100%. (Source)

Link to comment
Share on other sites

It looks like a sound design, which is expected from an experienced player like this. There are several unproven technologies here though, so there is a certain risk with the project: inflatable ballutes, detachable engines, and the entire BE engine.

The in-flight recovery by helicopter or airplane has been tried and tested since the 50's. I'm not sure it has been done with something as heavy as two engines though. I wonder if they will require the USAF to be on stand-by for the recovery ops or if they will charter their own chopper.

I like the 6-booster arrangement, which probably allows 0, 2 and 4 booster arrangements too, and maybe growth for an 8 booster configuration. I also like the single fairing arrangement, which protects the Centaur/ACES and also saves money on the interstage. I'm thinking that it might also offer additional structural support for the balloon tank.

Don't like the name. It sounds like it was chosen to please the trekkies, which is an annoying trend. Also, Vulcain is the name of the Ariane 5 engine.

Link to comment
Share on other sites

On the mid-air retrieval. Has anyone got an estimated mass of the stage that they want to recover? Guessing with numbers of engines of similar sizes in mind, I'd expect that stage to be at least 10t. I don't know any helicopters apart from ch47 that are capable of lifting such a weight and even with this one they have a set limit regarding theire recovery capabilities.

Maybe I've missed something here or my mass guesstimation is way off, but that whole mid-air retrieval does look like it's going to be seriously difficult to achieve on that scale. SpaceX first stage recovery looks a lot more realistic compared to this approach :/

Link to comment
Share on other sites

For those who find the engine reuse approach "odd" and prefer SpaceX's flyback model, here is the main advantage of the engine detach method:

They do not sacrifice performance. The rocket has partial reusability while still posting the same stats as it would if flying expendable. SpaceX, on the other hand, needs to reserve up to ~30% of their expendable payload to LEO in order to return the first stage alone (source).

The Vulcan rocket here however does not have to reserve any fuel for a boostback and landing maneuver, and does not require as much extra dry mass in support equipment. No duplicated avionics, no grid fins, no oversized RCS thrusters and tanks, no landing legs, no reinforced hull structure, and so on. It can fly like a fully expendable rocket does... and then ejects its engine block, which makes up about 65% of the cost of the entire rocket (as stated by ULA's infographic).

SpaceX recovers more - the entire first stage is valued by Elon Musk as about 75% of the total cost of the rocket - but has a lower payload fraction. Because of the Vulcan's higher payload fraction, the cost per kg to orbit on the Vulcan is lowered in comparison to the Falcon 9 when both fly in reusable configuration. As such, the extra money ULA spends on rebuilding the stage is amortized by the extra money earned from the high payload fraction, and not passed on to the customer. It's a pretty interesting model, and should be quite competitive.

Link to comment
Share on other sites

Why are we already replacing Atlas V and Delta IV? We should be improving and upgrading them. Of course the Atkas V uses Russian engines, but maybe it could be replaced?

Probably getting rid of the reliance on Soviet/Russian engines is a big part of it. And trying to get launch cost down, which likely isn't easy with the old designs (and yes, both Atlas and Delta are old designs, even if upgraded through the decades they're at heart 1960s and 1970s technology).

Link to comment
Share on other sites

They do not sacrifice performance. The rocket has partial reusability while still posting the same stats as it would if flying expendable. SpaceX, on the other hand, needs to reserve up to ~30% of their expendable payload to LEO in order to return the first stage alone (source).

This also avoids flyback manoeuvers and allows for an optimal launch trajectory, whereas SpaceX has to compromise its launch trajectory to facilitate the flyback trajectory.

On the other hand, the refurbishing will be more complex with the connection to the tanks, the ballute and chute repacking (it will probably be expendable), and you need a heavy-duty aircraft (Chinook or C130) on hand to pick up the engines in-flight, which isn't typically cheap to operate (unless the USAF takes care of it, but I don't see why they should).

Even though the engines are the most expensive part of the rocket, ULA's recovery process seems much more expensive than SpaceX's and they recover less equipment, so the economics are not clear-cut yet.

- - - Updated - - -

On the mid-air retrieval. Has anyone got an estimated mass of the stage that they want to recover? Guessing with numbers of engines of similar sizes in mind, I'd expect that stage to be at least 10t. I don't know any helicopters apart from ch47 that are capable of lifting such a weight and even with this one they have a set limit regarding theire recovery capabilities.

Maybe I've missed something here or my mass guesstimation is way off, but that whole mid-air retrieval does look like it's going to be seriously difficult to achieve on that scale. SpaceX first stage recovery looks a lot more realistic compared to this approach :/

I agree, mid-air retrieval on this scale has never been done, although there was a crazy plan in the 60's to build a giant helicopter to recover Saturn V first stages.

I think a C-130 might be more capable. It's also easier to operate for civilian operations than a CH-47.

Link to comment
Share on other sites

@streetwind: agreed the basic concept looks good and the payload issue is definitely a strong aspect, even if those numbers are rather optimistic and the whole refurbishing and maintenance costs will likely cut deep. SpaceX has yet to produce some real data aswell although they are ahead in development.

I'm still realy sceptical about the mid-air retrieval thing. I doubt that they will be able to pull off something like that on a regular schedule. I expect them to lose a significant number of engines, not that I don't wish them good luck with this approach. It just appears to be rly ambitious to catch an object of that size and weight mid air. And I doubt that this thing will return unguided without and extra avionics package and at least sone form of grid fins or rcs

Link to comment
Share on other sites

I'm still realy sceptical about the mid-air retrieval thing. I doubt that they will be able to pull off something like that on a regular schedule. I expect them to lose a significant number of engines, not that I don't wish them good luck with this approach. It just appears to be rly ambitious to catch an object of that size and weight mid air. And I doubt that this thing will return unguided without and extra avionics package and at least sone form of grid fins or rcs

Well, it's gonna be hanging from a parachute. Grid fins or RCS won't make much of a difference there. It'll have a small RCS system for re-entry orientation (unless they use the spent stage to properly orient the engine block pre-ejection), but other than that it'll be a ballistic object going down its flight path passively.

The mid-air retrieval isn't as difficult as you think; the concept's quite old, in fact. They don't even have to snag the engine, they just have to snag the parachute. Which is a really big, easy to hit target. The thing that makes it difficult is that the engine block will be so heavy that it'll require a fairly special helicopter to be able to carry it. And helicopter range is limited, so it will absolutely need a support ship on site that the helicopter launches from and lands back on with its captured payload. Maintaining that support ship and helicopter is going to cost non-trivial money. Still, ULA thinks they can pull it off and be cost competitive, and they're usually very conservative, so... *shrug*

Largely I'm disappointed that the whole shebang is still so many years away. They'll only start on reusability after the Vulcan successfully flies. So that means it'll be the 2020's before we get to see any actual, hot helicopter-on-engine action, and get more details on how ULA is planning to conquer the challenges involved. Until then, we can but speculate.

Link to comment
Share on other sites

This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...