4.04.2020
At various centers in the United States, Northrop Grumman is marching toward the OmegA rocket’s debut flight. The company has finalized the investigation of the nozzle anomaly on the C600 booster static fire test last year, and completed a successful C300 booster static test in February
Meanwhile, work continues at NASA’s Kennedy Space Center in Florida and the Michoud Assembly Facility in Louisiana, as elements of OmegA and its launch infrastructure remain on track for a first launch in Spring 2021.
KSC Launch infrastructure update:
At the Kennedy Space Center, work is progressing on modifications to the Mobile Launch Platform and High Bay 2 of the Vehicle Assembly Building.
These two elements are critical to Northrop Grumman as the Mobile Launch Platform is what OmegA will be stacked on and launched from while VAB High Bay 2 is where the rocket will be integrated prior to rollout to LC-39B for launch.
At present, all work is on track for Northrop Grumman to be able to stack the first OmegA rocket in High Bay 2 of the Vehicle Assembly Building in Spring 2021.
According to Charlie Precourt, Vice President for Propulsion Systems, Northrop Grumman, in an exclusive interview with NASASpaceflight, “We wanted to be able to do a pathfinder with the hardware by the fall, the coming fall and winter, so that in the spring we’d be ready to do launch operations. And I think we’re still on track to do that.”
Mr. Precourt touched upon the nature of the work to get OmegA’s ground infrastructure ready for its first missions.
“We’re continuing operations because of the national security nature of this work. We are continuing to make sure we have the vehicle ready. You know, the priority here is that the nation needs to get new vehicles to provide for National Security Space Launch, and the national security nature of that has put an urgency on our progress. So we’re pressing ahead.”
National Security elements have largely been exempted from COVID-19 lockdowns and work stoppages imposed by local and state officials, and Northrop Grumman is no different.
Speaking directly to the on-going reconfiguration of the Mobile Launch Platform from its Space Shuttle configuration to its role with OmegA, Mr. Precourt related that retrofits can be complicated, and teams can run into things they’re not expecting.
“The thing we have going for us is the way these platforms were set up for Shuttle — the flame trenches and so forth, the alignment — we were able to take advantage of a lot of that because the core of the OmegA is essentially the same size, form and fit, as a Space Shuttle Rocket Motor, or for that matter, for SLS.
“And so the fact that that unit has been held down on these platforms for decades is an advantage in making that transition.”
Moreover, construction of the launch umbilical tower is now underway on the Platform, with the first four elements of the tower’s base structure being attached within the last week. Northrop Grumman provided NASASpaceflight the following exclusive video clip of tower build operations:
The tower will be a miniature version of the one originally planned and partially built for the Ares I rocket as part of the now-cancelled Constellation Program.
“Because we have a cryo upper stage, [the tower] has to be able to manage cryos, it has to be able to help us with payload integration, encapsulation and so forth,” said Mr. Precourt.
To this end, the Mobile Launch Platform is the long pole item for OmegA.
Of work in Vehicle Assembly Building High Bay 2, Mr. Precourt noted, “It’s for the most part making sure we can do stacking operations on the Mobile Launch Platform. The platform is the long pole, and the High Bay is not going to be as significant a problem for us.
“We just need to make sure that electrical access lines and crane heights and hooks and all that stuff is properly configured and checked out for us.”
Mr. Precourt further expanded on that, confirming that a good way to think about this Vehicle Assembly Building High Bay configuration as opposed to SLS or Shuttle or Apollo is as a “bare-bones, minimal as possible” configuration.
Render of Mobile Launch Platform and OmegA in VAB High Bay 2 as a payload fairing is readied for stacking (Credit: Render provided to NASASpaceflight by Northrop Grumman for this article)
“We planned this so that we can get hardware arrived, have it shipped from Michoud, arrive, be stacked, and be launched within thirty days,” added Mr. Precourt.
C600 test stand anomaly resolution:
As part of preparations for OmegA’s first launch, Northrop Grumman has followed a standard set of procedures they have employed in other programs in test firing the solid rocket motor stages at their facility near Promontory, Utah.
Moreso, the C300 firing allowed Northrop Grumman to test a new nozzle design following an anomaly with the first stage C600 nozzle during a test firing last year.
“What you saw was an attempt to maximize the performance of that nozzle in terms of its weight and its performance in order to minimize the weight and maximize its performance,” said Mr. Precourt. “And because it was tested on the ground, what happened was the atmospheric pressure pushed in on the outside of the nozzle.
“During the final seconds, when the flow is reducing, it creates a vacuum on the inside of the nozzle. And that differential in force was more than we had expected. Had the rocket in fact done this 18,000-20,000 feet in the air, the atmospheric pressure would not have been sufficient to cause the anomaly.
“So that was very readily addressed. And frankly we were more concerned about the performance up inside the nozzle, where the insulation is in the throat of the nozzle, and we actually made some adjustments there between C600 and C300 so that we could assure ourselves we were solid.
“Frankly the anomaly you saw was really straightforward to adjust and fix from one to the next. So we’re feeling really good; the C300 nozzle has now been cut up and sliced and diced and analyzed, and we’re feeling really, really good right now about the design for both the 300 and the 600.”
Michoud Assembly Facility work:
Meanwhile, at the Michoud Assembly Facility in Louisiana, work continues on OmegA’s cryogenic third stage — the element of the rocket that will be responsible for placing the various payloads into fine-tuned, accurate orbits.
While Michoud is currently at Stage 4 of NASA’s coronavirus response level, with all work on all NASA projects stopped, Northrop Grumman is classified as vital to National Security efforts (as is OmegA) and is therefore able to continue working.
According to Mr. Precourt, all Northrop Grumman employees are following social distancing and safety guidelines to ensure cooperation with the Centers for Disease Control and Prevention (CDC) and all federal and state guidelines.
“We worked with NASA Headquarters on all of these programs where we are both at Kennedy and at Michoud,” noted Mr. Precourt. “The reality of it was, given as you’re seeing NASA do with its requirement to support the Space Station, they are continuing on mission critical things.
“And because this is a national security defense program using their resources, we were able to coordinate with NASA that we could continue work both at Kennedy and at Michoud on the tank.”
Mr. Precourt espoused optimism as to the status of the cryogenic stage, noting it was on track to support stacking operations in Spring 2021 and a first launch shortly thereafter.
A future variant of OmegA, with a 4-segment C1200 first stage and six side-mounted GEM-63XLT solid boosters, roars off the pad. (Credit: Mack Crawford for NSF L2)
The two RL10C engines for the first cryo stage are currently undergoing acceptance testing at the Aerojet Rocketdyne facility in West Palm Beach, Florida. Following the testing, they will be shipped to Michoud to be integrated into the upper stage in May.
This first cryogenic stage will be shipped to NASA’s Plum Brook facility in Ohio this fall after its completion in Louisiana.
At Plum Brook, it will undergo cryogenic fuel and oxidizer loading and unloading, as well as vacuum hot fire tests of its two RL10C-5-1 engines.
“The intent of sending the whole stage up to Plum Brook is that we would test it in the chamber, the altitude chamber at Plum Brook, so that we get a test firing of that stage,” noted Mr. Precourt.
The RL10 engine design has been in service in various iterations since 1962, with the 500th RL10 launching as the Centaur upper stage engine on the Atlas V 551 rocket on 26 March 2020 for the Space Force’s Advanced Extremely High Frequency 6 mission.
“The flight heritage of those engines would suggest high confidence, but since we’re able to test it, we’re going to go ahead and do so,” said Mr. Precourt.
This first-to-be-completed cryogenic stage will be used on the second flight of the OmegA rocket.
The first cryogenic stage to fly will be the second one completed at Michoud and will be shipped directly to Kennedy and integrated into the first Omega rocket in Spring 2021.
Stacking and launch operations:
At present, the first OmegA to fly will do so in the Intermediate Basic configuration, with a two segment Castor 600 solid rocket booster first stage, a single segment Castor 300 solid rocket booster second stage, and a dual RL10C engine cryogenic upper stage.
No side-mounted GEM-63XLT solid rocket boosters are planned for the first flight.
“At this point, [the first rocket is] the core. It’s what we call the Intermediate Basic. The current plan is to fly the Intermediate Basic as the first cert flight,” said Mr. Precourt.
The second flight will be the first to debut with side-mounted GEM-63XLT solid rockets and will fly with two of those.
OmegA will use a 5.2 meter payload fairing to encapsulate its payloads. Work on the first flight fairing is under way, built in Iuka, Mississippi — the same facility Northrop Grumman uses to make the Pegasus and Minotaur rocket payload fairings, the new pop-top fairing for Antares, and where the composite structures of the Atlas V and Delta IV rockets are made.
Once all launch infrastructure is ready at the Kennedy Space Center, the first of OmegA’s constituent components will be shipped to the launch site.
The operational goal is that once the first component of the vehicle arrives, OmegA will launch 30 days later from LC-39B — though first flight activities generally take longer to perform.
A happy OmegA rocket vents on LC-39B as it stands moments from liftoff on a mission for the U.S. Space Force. (Credit: Render provided to NASASpaceflight by Northrop Grumman for this article)
These 30 days of activities will involve receiving inspections and stacking preparations for the various stages, payload encapsulation, stacking of the rocket on the mobile launcher inside High Bay 2 of the Vehicle Assembly Building, functional and integrated checkouts of the rocket, and then rollout to launch pad 39B.
OmegA will be taken to Pad 39-B by the same Crawler Transporters that ferried all 13 Saturn Vs, four Saturn IBs, 138 Space Shuttle stacks (135 flight stacks, Enterprise test stack, the cancelled Challenger/51E stack, and Atlantis in 1986 for a non-flight test at Pad-B), and Ares I-X to the Kennedy pads.
Once at 39B, the mobile launcher will be connected to the ground infrastructure already in place at the pad — including fuel line hook ups for liquid oxygen and liquid hydrogen loading of the cryogenic stage.
All unique Ground Support Equipment for OmegA it does not share with SLS and Pad 39B will be contained within the Mobile Launch Platform itself, with Northrop Grumman able to use all other pad elements as part of the pad sharing agreement with NASA.
Most notably this will include access to the liquid hydrogen and liquid oxygen fuel loading systems and commodities for the cryogenic third stage.
Once at the launch pad, Northrop Grumman expects OmegA to be able to launch within a day or two, significantly shortening the amount of time the rocket needs to remain at the pad compared to its predecessor Saturn V, Saturn IB, and Space Shuttle rockets that occupied the pad in the past.
Flight performance validation of the first mission will be done via telemetry transmitted in real-time to the ground by the rocket via its own communications antennas as well as via the TDRS (Tracking and Data Relay Satellite) network from NASA during flight.
Unlike the Solid Rocket Boosters from the Space Shuttle era, there are no plans to recover the first stage of OmegA for post-flight inspections.
For launch operations, Northrop Grumman will make use of Firing Room 4 in the Launch Control Center next to the Vehicle Assembly Building.
Quelle: NS