ULA launch and discussion thread

[ThatGuyWithALongUsername]

Just now, DDE said:

Wait, Max Q happens before Mach 1? I did not know that.

I'm sure it depends on the vehicle, but that is kinda surprising.

[Scotius]

Finally it flew! Nice view, too - thanks to clear sky

[tater]

Coverage over. We'll have to wait and see, but Centaur is likely to do the same excellent job it always does.

[RedKraken]

Nice shot of the RL-10 deploying its extendable bell.

[Starman4308]

14 minutes ago, DDE said:

Wait, Max Q happens before Mach 1? I did not know that.

Not incredibly surprised. AFAIK, the transonic regime results in high aerodynamic stress, and if I did the calculations right, it has a 1.2 launch TWR. Combine that with the high specific impulse of hydrolox, and it gets going quite slowly at first.

[.50calBMG]

3 hours ago, tater said:

Coverage over. We'll have to wait and see, but Centaur is likely to do the same excellent job it always does.

... wanna think about that for a sec?

[tater]

18 minutes ago, .50calBMG said:

... wanna think about that for a sec?

The last Centaur failure was over 11 years ago, right? It's had what, 12 mishaps out of nearly 250 flights, and most of those in the 60s and 70s.

[Canopus]

This is a Delta Cryogenic Second stage though. Still RL10 of course. And i think it only had a partial failure once while launched on a Delta IV.

[tater]

My bad, I forgot it was the DCSS, not Centaur. DCSS would be a better stage if it was just a bigger Centaur.

[.50calBMG]

There ya go

And I would agree with that, more usable volume vs stage size. looks like they learned their lesson on that too, ACES has the common bulkhead and same diameter tanks like Centaur does.

Edited January 20, 2019 by .50calBMG

[tater]

58 minutes ago, .50calBMG said:

There ya go

I spaced it, had your reply been more explicit I would have immediately reacted accordingly, instead, I looked for why Centaur might not be considered reliable. Mea culpa.

[.50calBMG]

Yeah, but where's the fun in instant gratification? Back to ULA, have we heard anything recently about ACES? Seems like its been a while since we had an update on it.

[tater]

They're going with a giant Centaur to start with Vulcan. Unsure about the path to ACES, though they still show it in promo materials.

[DDE]

Any idea why, on NROL-71 of all times, ULA has decided to end the practice of live Mission Control audio?

Edited January 28, 2019 by DDE

[Xd the great]

45 minutes ago, DDE said:

Any idea why, on NROL-71 of all times, ULA has decided to end the practice of live Mission Control audio?

"Deploying spy camera"

[DDE]

9 minutes ago, Xd the great said:

"Deploying spy camera"

And not the previous dozens?

And on all the following launches?

[MaverickSawyer]

The NRO is a strange beast, and if ULA wishes to keep flying payloads for them, they must abide by their wishes.

[Ultimate Steve]

Maybe it's a ploy to attract employees. If they enshroud everything in mystery, people of this next generation will want to know the secrets, and the only way to do that is to be a foreign spy or an employee.

[DDE]

3 hours ago, MaverickSawyer said:

The NRO is a strange beast

Well, they can’t hold a wet candle to NURO, and its ‘red’ cousin GUGI. Literally murky agencies.

[Racescort666]

4 minutes ago, DDE said:

Well, they can’t hold a wet candle to NURO, and its ‘red’ cousin GUGI. Literally murky agencies.

Since we're talking about intelligence agencies and not an autonomous vehicle start-up nor a village in Iran, I will ask who those organizations are? Maybe it puts me on some kind of list just for asking or the answer is "those who need to know, already know."

[DDE]

17 minutes ago, Racescort666 said:

Since we're talking about intelligence agencies and not an autonomous vehicle start-up nor a village in Iran, I will ask who those organizations are? Maybe it puts me on some kind of list just for asking or the answer is "those who need to know, already know."

The National Underwater Research Organization is on the Wiki, it’s just basically an orphan article that doesn’t get a redirect, evidently. Which is ironic for an organization that engages mostly in cable-tapping and illigal salvage of foreign debris and submarine hulks - a permanent form of the old Glomar Explorer slavage mission, it seems.

The Main Directorate for Deepwater Research is similarily engaged in storming the other final frontier with their “deepwater nuclear stations” and their “aquanauts”... when they’re not getting accidental coverage in Top Gear.

[MaverickSawyer]

Hmm. I'm of the opinion that at least some of the activities you listed are actually carried out by SUBDEVRON 5, the US Navy's "experimental" and test submarine unit. Said unit is the operator of the U.S.S. Jimmy Carter, which is essentially tailor made to replace the U.S.S. Parche, which is widely held to have taken part in clandestine and intrusive espionage operations throughout it's long and largely classified career. The fact that the Carter was at sea during a recent round of North Korean missile tests and returned to Bremerton a few weeks later flying the Jolly Roger did not go unnoticed by many...

 

On a somewhat more topical note, Blue Origin has broken ground on the factory that will provide first stage engines for Vulcan.

[IncongruousGoat]

On 1/19/2019 at 7:21 PM, tater said:

My bad, I forgot it was the DCSS, not Centaur. DCSS would be a better stage if it was just a bigger Centaur.

Every time I look at the DCSS, I can't help but cringe at what all that non-tank metal does to the dry mass. I can't even tell what that ring around the LOX tank is for, other than maybe stabilizing the stage against the inside of the fairing.

On 1/19/2019 at 7:24 PM, .50calBMG said:

There ya go

And I would agree with that, more usable volume vs stage size. looks like they learned their lesson on that too, ACES has the common bulkhead and same diameter tanks like Centaur does.

Not all versions of Centaur had same diameter tanks. The one that flew on Titan IV (Centaur G, IIRC) had multiple-diameter tanks. I agree, though, common bulkhead and same diameter is the way to go.

[.50calBMG]

Centaur G still had a common bulkhead though. Makes me wonder what the thought process was for the separate tanks on the DCSS.

[Starman4308]

57 minutes ago, IncongruousGoat said:

Every time I look at the DCSS, I can't help but cringe at what all that non-tank metal does to the dry mass. I can't even tell what that ring around the LOX tank is for, other than maybe stabilizing the stage against the inside of the fairing.

Most of that looks to me like an instrument ring, wiring, piping, etc.

I somewhat suspect that ring around the LOX tank might be the structural element connecting the second stage to the interstage, and thus has to deal with a fair bit of force.

17 minutes ago, .50calBMG said:

Centaur G still had a common bulkhead though. Makes me wonder what the thought process was for the separate tanks on the DCSS.

Delta and Centaur came from different companies before they merged into ULA. Different companies, different design philosophies, etc.

Common bulkheads for hydrolox stages aren't easy, either; the hydrogen can freeze the LOX, and the LOX can boil the hydrogen.

Edited January 29, 2019 by Starman4308