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#180 by tmoesser on 19 Sep, 2019 19:37
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OK, so what are the "ground test phenomenon" options? Something about the exhaust plume expansion interacting with the ground and reflecting heat back, etc.?
Primary phenomenon is flow separation shock at ambient pressure which would be negligible at altitude. The heat reflection you mentioned is probably contributing as well.John Steinmeyer
I figured you must have meant Steinmeyer. CASTOR 1200 will use a lower burning rate propellant than C600 and C300 to keep loads down, so not quite double the thrust ("3 million" is right to one significant figure) and slightly longer burn time.
Presenting here today.
Just said that the heavy lift cast-12 version has 3 million pounds of thrust plus the Gem63xlt strap on boosters. Not 4 Mlbs plus the srb's.
Ned
Edit add 1st name 2nd, correct name -
#181 by russianhalo117 on 19 Sep, 2019 22:23
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I thought that C1200 was to have a variable propellant mix and form to tailor thrust to the G loads profile. In other words high thrust at T-0 and lower thrust by the end.OK, so what are the "ground test phenomenon" options? Something about the exhaust plume expansion interacting with the ground and reflecting heat back, etc.?
Primary phenomenon is flow separation shock at ambient pressure which would be negligible at altitude. The heat reflection you mentioned is probably contributing as well.John Steinmeyer
I figured you must have meant Steinmeyer. CASTOR 1200 will use a lower burning rate propellant than C600 and C300 to keep loads down, so not quite double the thrust ("3 million" is right to one significant figure) and slightly longer burn time.
Presenting here today.
Just said that the heavy lift cast-12 version has 3 million pounds of thrust plus the Gem63xlt strap on boosters. Not 4 Mlbs plus the srb's.
Ned
Edit add 1st name 2nd, correct name -
#182 by StarryKnight on 20 Sep, 2019 22:21
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“The nozzle exit cone break up that occurred at motor shut down was caused by a ground test phenomenon that would not have occurred in flight," @northropgrumman told @Florida_Today in regards to #OmegA anomaly. Story by @Rachael_Joy.
OK, so what are the "ground test phenomenon" options? Something about the exhaust plume expansion interacting with the ground and reflecting heat back, etc.?
- Ed Kyle
I don't think heat reflected from the ground would be any hotter than the thrust exiting the nozzle. I was thinking this referred to acoustic reflection from the ground, perhaps for an extended period of time. In flight, ground reflection wouldn't last very long.
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#183 by NH22077 on 21 Sep, 2019 01:12
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.......
I thought that C1200 was to have a variable propellant mix and form to tailor thrust to the G loads profile. In other words high thrust at T-0 and lower thrust by the end.
Snip.
.......
CASTOR 1200 will use a lower burning rate propellant than C600 and C300 to keep loads down, so not quite double the thrust ("3 million" is right to one significant figure) and slightly longer burn time.
I don't remember John mentioning a tailored thrust profile for the C1200.
There were 4.5 hours of presentations. On OmegA with a lunch break. So I might have missed it.
I could have recorded it, but there was no interest in my first post.
There were only 32 people in the audience. 16 after lunch.
Ned -
#184 by novak on 23 Sep, 2019 02:22
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OK, so what are the "ground test phenomenon" options? Something about the exhaust plume expansion interacting with the ground and reflecting heat back, etc.?
- Ed Kyle
I don't think heat reflected from the ground would be any hotter than the thrust exiting the nozzle. I was thinking this referred to acoustic reflection from the ground, perhaps for an extended period of time. In flight, ground reflection wouldn't last very long.
I agree with you.
The heating environment on the ground is usually boring because the plumes are overexpanded at sea level. It's not until you get to high altitude that you start seeing really aggressive base heating environments. Acoustics are different depending on what they can reflect off of. Kind of a wimpy excuse- they have to be able to test at sea level so that's part of the loading that they should design to. Probably doesn't really matter, I'm sure they'll fix it. -
#185 by Lars-J on 25 Sep, 2019 05:21
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“The nozzle exit cone break up that occurred at motor shut down was caused by a ground test phenomenon that would not have occurred in flight," @northropgrumman told @Florida_Today in regards to #OmegA anomaly. Story by @Rachael_Joy.
OK, so what are the "ground test phenomenon" options? Something about the exhaust plume expansion interacting with the ground and reflecting heat back, etc.?
Yet this has never happened during any previous SRB test from the same stand - to my knowledge. -
#186 by edkyle99 on 25 Sep, 2019 13:36
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This is a new nozzle that, as far as I know, has never been tested there. I think it has a bigger expansion ratio, etc.“The nozzle exit cone break up that occurred at motor shut down was caused by a ground test phenomenon that would not have occurred in flight," @northropgrumman told @Florida_Today in regards to #OmegA anomaly. Story by @Rachael_Joy.
OK, so what are the "ground test phenomenon" options? Something about the exhaust plume expansion interacting with the ground and reflecting heat back, etc.?
Yet this has never happened during any previous SRB test from the same stand - to my knowledge.
- Ed Kyle -
#187 by russianhalo117 on 25 Sep, 2019 15:44
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AFAIU it is derived from SLS nozzle but newer materials developed with NASA and AFRL (and some other national Labs) and other changes.
This is a new nozzle that, as far as I know, has never been tested there. I think it has a bigger expansion ratio, etc.“The nozzle exit cone break up that occurred at motor shut down was caused by a ground test phenomenon that would not have occurred in flight," @northropgrumman told @Florida_Today in regards to #OmegA anomaly. Story by @Rachael_Joy.
OK, so what are the "ground test phenomenon" options? Something about the exhaust plume expansion interacting with the ground and reflecting heat back, etc.?
Yet this has never happened during any previous SRB test from the same stand - to my knowledge.
- Ed Kyle -
#188 by niwax on 25 Sep, 2019 21:52
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This is a new nozzle that, as far as I know, has never been tested there. I think it has a bigger expansion ratio, etc.“The nozzle exit cone break up that occurred at motor shut down was caused by a ground test phenomenon that would not have occurred in flight," @northropgrumman told @Florida_Today in regards to #OmegA anomaly. Story by @Rachael_Joy.
OK, so what are the "ground test phenomenon" options? Something about the exhaust plume expansion interacting with the ground and reflecting heat back, etc.?
Yet this has never happened during any previous SRB test from the same stand - to my knowledge.
- Ed Kyle
Without any particular knowledge, I first read it as a hardware difference because of the ground test, eg an early development nozzle, or a variant better suited to ground testing. -
#189 by Lars-J on 25 Sep, 2019 23:31
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This is a new nozzle that, as far as I know, has never been tested there. I think it has a bigger expansion ratio, etc.“The nozzle exit cone break up that occurred at motor shut down was caused by a ground test phenomenon that would not have occurred in flight," @northropgrumman told @Florida_Today in regards to #OmegA anomaly. Story by @Rachael_Joy.
OK, so what are the "ground test phenomenon" options? Something about the exhaust plume expansion interacting with the ground and reflecting heat back, etc.?
Yet this has never happened during any previous SRB test from the same stand - to my knowledge.
I doubt it has a bigger expansion ratio, it is still meant to be launched at sea level. New materials maybe... -
#190 by jacqmans on 11 Oct, 2019 14:34
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OmegA Team Values Partnerships with Customer, Suppliers
As aerospace and defense suppliers from across the country took their seats at Constitution Hall in Washington D.C., a gleaming 18-foot-tall OmegA rocket model on the stage commanded their attention. The event was the third annual OmegA suppliers conference, and judging from the overall reaction to the 1/12-scale model, the only thing the suppliers would have liked to see more was an actual rocket ready to launch.
“On behalf of the OmegA program, we appreciate all of your contributions,” said Kent Rominger, vice president, OmegA business development, Northrop Grumman. “The OmegA team works as a true partner with the Air Force, and that partnership extends to our suppliers.” Rominger said key elements of this partnership are transparency, shared goals and 100 percent focus on the customer’s mission. His message resonated with attendees, who have one critical goal in common -- supporting the initial launch of OmegA from NASA’s Kennedy Space Center in early 2021.
Northrop Grumman hosted this event to share the team’s progress on the rocket and ground support systems, and apprise attendees of the program’s upcoming milestones. OmegA’s 146 suppliers, located in 32 states, provide everything from microchips, wire harnesses and cryogenic tank assemblies to entire rocket engines. For those who provide a single component, it was exciting to see hardware photos demonstrating how much the OmegA team has accomplished since Northrop Grumman received a Launch Services Agreement from the U.S. Air Force last year.
Mike Laidley, vice president, OmegA, Northrop Grumman, asked attendees to pass on to their teams his appreciation for all the hard work they have done so far. Then he shared with suppliers significant progress on each major subsystem, including the successful completion of the first static fire test earlier this year.
“Incredible collaboration and commitment has got us to where we are today and will carry us into the future,” said Kevin Wilder, program manager, OmegA, Northrop Grumman. “There has been really solid work with industry partners to meet national security space needs.”
Throughout the conference, Northrop Grumman stressed that each supplier plays a critical role ensuring assured access to space for the U.S. Air Force. At the end of the day, suppliers returned to their manufacturing plants carrying messages of appreciation and the value of true partnership. Every member of the team is doing its part to get OmegA ready to fly in 2021.
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#191 by ZachS09 on 14 Oct, 2019 04:54
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Will the GEM-63XL boosters be jettisoned during the first stage burn or will they stay attached after Stage 1 sep and Stage 2 ignition?
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#192 by Steven Pietrobon on 14 Oct, 2019 06:25
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Will the GEM-63XL boosters be jettisoned during the first stage burn or will they stay attached after Stage 1 sep and Stage 2 ignition?
I don't know, but my expectation is that they would be jettisoned so as to give better performance. -
#193 by edkyle99 on 14 Oct, 2019 14:09
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That would be my guess. GEM-63XL burn time is something like 84 seconds while Castor 600 is roughly two minutes.Will the GEM-63XL boosters be jettisoned during the first stage burn or will they stay attached after Stage 1 sep and Stage 2 ignition?
I don't know, but my expectation is that they would be jettisoned so as to give better performance.
- Ed Kyle -
#194 by ZachS09 on 14 Oct, 2019 15:17
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That would be my guess. GEM-63XL burn time is something like 84 seconds while Castor 600 is roughly two minutes.Will the GEM-63XL boosters be jettisoned during the first stage burn or will they stay attached after Stage 1 sep and Stage 2 ignition?
I don't know, but my expectation is that they would be jettisoned so as to give better performance.
- Ed Kyle
Do you know how long Castor 1200 will burn for? I think it might be two and a half minutes, but I could be wrong. -
#195 by spacenut on 14 Oct, 2019 18:22
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Would it pay NGIS to make the solid booster and second stage modules out of stainless steel in order to parachute them back down for reuse? Kind of like the shuttle boosters, but could resist heat better than composite on return. Seems a waste to dunk them.
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#196 by whitelancer64 on 14 Oct, 2019 20:49
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Would it pay NGIS to make the solid booster and second stage modules out of stainless steel in order to parachute them back down for reuse? Kind of like the shuttle boosters, but could resist heat better than composite on return. Seems a waste to dunk them.
The Shuttle's SRB casings were made out of stainless steel to begin with. The casings were made from stainless both to withstand the heat loads experienced prior to parachute recovery, and to not corrode due to salt water immersion.
The entire point of switching to a composite casing is to reduce weight, not to withstand reentry heat loads, since they aren't recovering and reusing them. -
#197 by edkyle99 on 14 Oct, 2019 21:30
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Do you know how long Castor 1200 will burn for? I think it might be two and a half minutes, but I could be wrong.
I don't, but my guess would be that the SLS five-segment booster, which burns for 128 seconds, is a useful model to consider. Four-segment booster was 124 seconds. Solid motor length principally increases thrust, not burn time, though the thrust/time profile can be tailored in various ways.
- Ed Kyle -
#198 by PM3 on 23 Oct, 2019 15:45
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Full OmegA specs!
Medium Heavy (kg)
LEO 22,000 23,200
SSO 15,500 18,000
MTO 8,900 13,200
MEO 5.400 9,300
GTO 9,200 14,000
GEO 3,200 6,700
TLI 7,000 12,300+ mT
Escape 6,400 10,700
Mars 5,000 12,000+ mT
https://twitter.com/Tschnn/status/1187009600450682885 -
#199 by edkyle99 on 23 Oct, 2019 16:00
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That "Medium" is formidable all by itself. 1.67 times more payload to GTO than a Falcon 9 with reuse. 1.15 times more than Falcon Heavy full reuse. 1.37 times more than Vulcan Centaur 522. More than any Atlas 5.
- Ed Kyle