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#380 by Kansan52 on 27 Aug, 2020 18:44
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*Opinions are that of the author, not authorized to speak on behalf of the company, not a forward-looking statement, past performance is not a guarantee of future results, your mileage may vary, not valid in all states, caveat emptor, nolo contendere, e pluribus unum, et cetera ad nauseam.
Nice! -
#381 by TrevorMonty on 27 Aug, 2020 20:33
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I for one would like to see Omega fly, unfortunately its to late to soon to be crowded market. If it had been flying couple years ago would've done well when only competition is A5, F9 and unreliable Proton. With year or two of flights behind it would've been top contender for NSSL competition.
Could also say same about Vulcan and NG, timing is everything. -
#382 by edzieba on 28 Aug, 2020 10:11
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throttle gives you a knob to re-optimize that you have access to after the vehicle is designed. We can't recast those solids to add or remove a fin on launch day.
On launch day, sure. But was there any intent to cast specific solid cores for different mission profiles to deliver different burn profiles? Or with the fixed stage diameter, nozzle and throat does that mostly end up as a rounding error that isn't worth the hassle? -
#383 by TrevorMonty on 28 Aug, 2020 14:03
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Adding strapon SRMs allows for some modifications to LV performance without changing SRBs design. The liquid US stage will have lot of flexibility.throttle gives you a knob to re-optimize that you have access to after the vehicle is designed. We can't recast those solids to add or remove a fin on launch day.
On launch day, sure. But was there any intent to cast specific solid cores for different mission profiles to deliver different burn profiles? Or with the fixed stage diameter, nozzle and throat does that mostly end up as a rounding error that isn't worth the hassle? -
#384 by FutureSpaceTourist on 09 Sep, 2020 21:37
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Finally official:
https://twitter.com/sandra_i_erwin/status/1303793354220744704QuoteBreaking news: Northrop Grumman tells SpaceNews it will not move forward with the development of the OmegA rocket. It will not protest the Air Force's decision to not select OmegA for national security space launch.
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#385 by ncb1397 on 09 Sep, 2020 21:42
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Quote
Northrop Grumman announced it will not move forward with the development of the OmegA rocket. The vehicle was designed for the sole purpose of competing for a National Security Space Launch contract award but didn’t make the cut.
https://spacenews.com/northrop-grumman-to-terminate-omega-rocket-program/
“We have chosen not to continue development of the OmegA launch system at this time,” Northrop Grumman spokeswoman Jennifer Bowman said in a statement. “We look forward to continuing to play a key role in National Security Space Launch missions and leveraging our OmegA investments in other activities across our business.” -
#386 by edkyle99 on 11 Sep, 2020 15:15
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[Ares I vs. OmegA]
One was two stage with a big J-2X powered upper stage. The other was three stage using RL10 powered upper stage. One used steel solid motor cases on a five segment booster. The other used composite case motors on two solid stages - one a two or four-segment motor and the other a single-segment motor. The two rockets used different length/mass solid motor segments and two different solid propellant formulations. One had no strap on motors. The other would have used strap on motors.
Two completely different rockets.
- Ed Kyle
[zubenelgenubi: Edits by Chris B and zubenelgenubi. Discussion contained no L2-level information, so I moved such to the public-side OmegA updates and discussion thread.] -
#387 by Chris Bergin on 11 Sep, 2020 21:27
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#388 by Scotty on 12 Sep, 2020 13:55
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One was two stage with a big J-2X powered upper stage. The other was three stage using RL10 powered upper stage. One used steel solid motor cases on a five segment booster. The other used composite case motors on two solid stages - one a two or four-segment motor and the other a single-segment motor. The two rockets used different length/mass solid motor segments and two different solid propellant formulations. One had no strap on motors. The other would have used strap on motors.
Two completely different rockets.
- Ed Kyle
Thrust oscillation would have still made for a very rough ride for payloads.
Big, inline solid rocket motors make it very difficult to dampen out thrust oscillation issues.
Go back and review Ares 1's thrust oscillation issues.
Ares 1X used a four segment first stage, and thrust oscillation was very high on that first and thankfully only test flight. -
#389 by edkyle99 on 12 Sep, 2020 16:18
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One was two stage with a big J-2X powered upper stage. The other was three stage using RL10 powered upper stage. One used steel solid motor cases on a five segment booster. The other used composite case motors on two solid stages - one a two or four-segment motor and the other a single-segment motor. The two rockets used different length/mass solid motor segments and two different solid propellant formulations. One had no strap on motors. The other would have used strap on motors.
Two completely different rockets.
- Ed Kyle
Thrust oscillation would have still made for a very rough ride for payloads.
Big, inline solid rocket motors make it very difficult to dampen out thrust oscillation issues.
Go back and review Ares 1's thrust oscillation issues.
Ares 1X used a four segment first stage, and thrust oscillation was very high on that first and thankfully only test flight.
"The much ballyhooed thrust oscillations the vehicle might encounter were basically non-existent on Wednesday’s test flight. “We had two sensors to measure this and so far the oscillations look very small, similar to what the shuttle might encounter,” Ess said. “We didn’t see anything unusual or remotely like anything to indicate that thrust oscillation was a factor.”"
https://www.universetoday.com/43778/ares-i-x-manager-addresses-booster-damage-stage-tumbling-and-thrust-oscillation/
This was a four-segment booster. It was the extension to five-segments for Ares I, combined with the resonances of the Ares I launch vehicle altogether, that raised the thrust oscillation concern. Omega's solids were all shorter than five-segment booster. Even Castor 1200 would have been closer to an STS four-segment length. All newly engineered with thrust oscillation managed from the outset in the total vehicle design, to prevent such resonances.
Resonance/pogo can afflict liquid rockets too. Some kind of control system oscillation (maybe [triggered by?] sloshing or who knows what else) brought down that Astra Rocket this morning, for example.
- Ed Kyle
[zubenelgenubi: slight edit]
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#390 by su27k on 14 Sep, 2020 03:36
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[Ares I vs. OmegA]
One was two stage with a big J-2X powered upper stage. The other was three stage using RL10 powered upper stage. One used steel solid motor cases on a five segment booster. The other used composite case motors on two solid stages - one a two or four-segment motor and the other a single-segment motor. The two rockets used different length/mass solid motor segments and two different solid propellant formulations. One had no strap on motors. The other would have used strap on motors.
Two completely different rockets.
1. two stage vs three stage: There're many launch vehicle which has optional 3rd stage, Delta-II for example, a 2 stage Delta-II is still Delta-II, so is a 3 stage Delta-II, still the same rocket family.
2. Different upper stage engines: Also fairly common when a launch vehicle evolves, either on paper or in hardware. New Glenn changed upper stage engine during design phase, Delta-II also changed 2nd stage engine from TR-201 to AJ10, still the same rocket family.
3. Casing: Shuttle external tank changed from using 2219 aluminum-copper alloy to 2195 aluminium-lithium alloy with friction stir welding, still the same rocket family.
4. Fuel: Vulcan maintained two different fuel (RP-1 vs methane) in design until recently, Soyuz-2 switched from RG-1 to naftil, still the same rocket family.
5. Length: Frequently changed on liquid boosters, Falcon 9 changed length several times, Antares too, still the same rocket family.
6. Strapons: Many launch vehicles have different strapon configurations, Atlas V 401 vs 551 for example, still the same rocket family.
So none of these makes OmegA a completely different rocket from Ares-I. -
#391 by JEF_300 on 14 Sep, 2020 06:38
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[Ares I vs. OmegA]
One was two stage with a big J-2X powered upper stage. The other was three stage using RL10 powered upper stage. One used steel solid motor cases on a five segment booster. The other used composite case motors on two solid stages - one a two or four-segment motor and the other a single-segment motor. The two rockets used different length/mass solid motor segments and two different solid propellant formulations. One had no strap on motors. The other would have used strap on motors.
Two completely different rockets.
1. two stage vs three stage: There're many launch vehicle which has optional 3rd stage, Delta-II for example, a 2 stage Delta-II is still Delta-II, so is a 3 stage Delta-II, still the same rocket family.
2. Different upper stage engines: Also fairly common when a launch vehicle evolves, either on paper or in hardware. New Glenn changed upper stage engine during design phase, Delta-II also changed 2nd stage engine from TR-201 to AJ10, still the same rocket family.
3. Casing: Shuttle external tank changed from using 2219 aluminum-copper alloy to 2195 aluminium-lithium alloy with friction stir welding, still the same rocket family.
4. Fuel: Vulcan maintained two different fuel (RP-1 vs methane) in design until recently, Soyuz-2 switched from RG-1 to naftil, still the same rocket family.
5. Length: Frequently changed on liquid boosters, Falcon 9 changed length several times, Antares too, still the same rocket family.
6. Strapons: Many launch vehicles have different strapon configurations, Atlas V 401 vs 551 for example, still the same rocket family.
So none of these makes OmegA a completely different rocket from Ares-I.
Maybe not individually. But if everything is just a little different, it's still different in every way. -
#392 by FinalFrontier on 14 Sep, 2020 09:40
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Bottom line and all of this is IMHO of course:
Large segmented solid rocket motors just suck really. They are expensive and complex to make not to mention time consuming. They are very sensitive to environmental factors on the ground and have to be stored and handled very carefully. They have a wide variety of mission ending failure modes you cannot abort off of. They cannot be turned off once lit, restarted, or effectively controlled in the same ways as any liquid engine. They vibrate, shake, and are generally violent devices and they have a tendency to damage their own launch pads.
They also cannot be effectively re-used and they effectively prevent re-use of the LV they are integrated with.
Small scale solids make sense as boosters for liquid LVs. Solid motor first stages make sense for missiles and strategic deterrent devices requiring prompt launch on warning capability.
However these applications are where it begins and ends. The engineering community has known this for multiple decades which is why people consistently tried to tell congress and NASA pre-esas and even before Columbia that solids should be done away with in future programs.
I view this as a fitting end to the stick saga and the general obsession of certain parties with large scale solid motors and it's about time honestly.
I believe this also proves once again that an LRB based SLS would have been superior and should have been what was chosen had the decision been merit based and non political.
In any case my hope for the future here is that this zombie and dead end technology is finally dead as it should be. We know and have known for awhile now what rocket technology works and what rocket technology does not work. Time to stop pretending large solid motors are anything but a dangerous money pit.
I do have to applaud NGIS for trying to make this work one last time, and they certainly got farther along than all the predecessors of the stick got.
The stick is finally dead. Will not be missed.
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#393 by woods170 on 14 Sep, 2020 11:15
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Bottom line and all of this is IMHO of course:
<snip>
The stick is finally dead. Will not be missed.
Let's hope so.
Von Braun was right. And everyone knew he was right. But today we're still stuck with solids (SLS) thanks to penny-pinching NASA administrator James C. Fletcher. He over-ruled Von Braun over what was essentially pocket-change with regards to NASA's budget.
Amazing that seemingly small choices have profound effects in the decades afterwards. -
#394 by Zed_Noir on 14 Sep, 2020 16:13
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<snip>
The stick is finally dead. Will not be missed.
Well the undead always find a way to hang around.
If the Congressional Critters is seeking continual large SRM production in Utah. Could see large segmented SRMs as strapped-on stage for a "Titanized" Vulcan HLV flying from pad LC-39B and be a tenant at the VAB.
A monstrosity consisting of a pair of Castor 600 with optional GEM-63XL supplemental SRBs as the first stage strapped to an air start Vulcan core along with stretched Centaur-V upper stage.
The scary thing is that all the flight hardware is already in the pipeline for SLS and Vulcan-Centaur. All that is missing is a MLP with a cropped launch tower. Oh, wait isn't there a half build MLP at KSC...
However, hoped the "Stick" is finally toasted. I will see myself out.
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#395 by baldusi on 14 Sep, 2020 22:29
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Hasn't the senator that represented Utah and kept insisting on the solids retired?
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#396 by Zed_Noir on 14 Sep, 2020 22:37
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Hasn't the senator that represented Utah and kept insisting on the solids retired?
Doesn't matter. The current Utah Congressional Critters will try to preserved the jobs associated with large segmented SRM. There is a lot of funding at stake.
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#397 by Steven Pietrobon on 15 Sep, 2020 09:03
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4. Fuel: Vulcan maintained two different fuel (RP-1 vs methane) in design until recently, Soyuz-2 switched from RG-1 to naftil, still the same rocket family.
Naftil and RG-1 are the same. However, Soyuz did use Syntin which is different to RG-1. -
#398 by MATTBLAK on 15 Sep, 2020 09:56
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I was all for SLS having hydrocarbon, reusable 'flyback' boosters that would land on the old Shuttle runway. But of course; you can't always get what you want...Bottom line and all of this is IMHO of course:
<snip>
The stick is finally dead. Will not be missed.
Let's hope so.
Von Braun was right. And everyone knew he was right. But today we're still stuck with solids (SLS) thanks to penny-pinching NASA administrator James C. Fletcher. He over-ruled Von Braun over what was essentially pocket-change with regards to NASA's budget.
Amazing that seemingly small choices have profound effects in the decades afterwards.
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#399 by baldusi on 16 Sep, 2020 19:17
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Somebody should run the numbers on AJAX with four F9 boosters.
I was all for SLS having hydrocarbon, reusable 'flyback' boosters that would land on the old Shuttle runway. But of course; you can't always get what you want...Bottom line and all of this is IMHO of course:
<snip>
The stick is finally dead. Will not be missed.
Let's hope so.
Von Braun was right. And everyone knew he was right. But today we're still stuck with solids (SLS) thanks to penny-pinching NASA administrator James C. Fletcher. He over-ruled Von Braun over what was essentially pocket-change with regards to NASA's budget.
Amazing that seemingly small choices have profound effects in the decades afterwards.
