Next Generation Launcher

SpaceNut · 2018-04-04 18:01:58

I am sure that we have talked about this somewhere but not under its own topic. Yes this basically Ares 1 rehashed...

Orbital ATK preparing for next phase of NGL rocket development

Orbital ATK is preparing for the next phase of development for their Next Generation Launcher (NGL) – a solid and liquid fueled rocket designed for National Security, NASA science missions, and commercial flights. Under the current plan, Orbital ATK intends to introduce NGL from LC-39B at the Kennedy Space Center, FL, with certification flights in early 2021, with operational flights set to begin later that year.
NGL aims for debut in three years:
The progeny of NGL can be traced back to 2004, when then U.S. President George W. Bush announced the Constellation program, consisting of the crew launch vehicle known as Ares I – a five-segment Solid Rocket Booster (SRB) rocket, atop which sat a Liquid Oxygen/Liquid Hydrogen (LOX/LH2) upper stage.
A test flight variant of Ares I, known as Ares I-X, completed a successful test flight on 29 October 2009, shortly after which the Constellation program was cancelled by then U.S. President Barack Obama in favor of developing a more robust rocket that could carry both crew and cargo, the SLS, to locations Beyond Low Earth Orbit and shifting International Space Station crew rotation missions from NASA-made rockets to commercial rockets and capsules – a goal SpaceX and Boeing plan to fulfill.
Despite the Constellation program’s cancellation, Orbital ATK, the predecessor of which would have built the five-segment SRB for Ares I and the company that is now building the five-segment dual SRBs for SLS, continued to see a usefulness for the overall Ares I design. This initially translated in 2011 to the Liberty rocket, a five-segment SRB first stage with an Ariane V core serving as the upper stage.
By May 2016, this overall design was incorporated into Orbital ATK’s participation and contract award from the U.S. Air Force as part of the Air Force’s Rocket Propulsion Systems Development project to replace the Russian-made RD-180 engine used on United Launch Alliance’s Atlas V rocket and to also streamline the EELV (Evolved Expendable Launch Vehicle) program to reduce the overall cost and increase efficiency of U.S. rockets used for national security and government missions.
Orbital ATK, with NGL, has passed through the first two phases of the Rocket Propulsion System Development project, with Phase 3, now called the Launch Service Agreement, awards scheduled to be announced by the end of July 2018.
Orbital ATK has already been told by the Air Force that NGL is within the competitive range of the program, and the company hopes that the Phase 3 awards – which will continue partial Air Force funding for the development of NGL – will allow the vehicle to maintain its overall development schedule and be certified for national security missions and be available for competitive commercial launches in 2021.
Recently, NASASpaceflight’s Chris Gebhardt talked with Mike Laidley, Vice President of Space Launch Programs for Orbital ATK, about NGL’s development and future. “The initial launch – which will be the intermediate configuration – will fly in the first quarter of 2021 for a certification flight,” stated Mr. Laidley. “We have two certification flights planned for 2021, and then we’ll be in regular launching activity late in the year 2021.”
Under this plan, Orbital ATK will have NGL fully certified for government missions by the end of 2021 and hopes to offer the initial two certification flights at reduced cost to commercial companies for LEO (Low Earth Orbit) or GEO (Geostationary Orbit) missions.
The two certification flights will utilize the intermediate variant of NGL, consisting of a two-segment SRB (the C-600) first stage, a single-segment (C-300) SRB second stage, and a 70,000 lbs propellant load LOX/LH2 upper stage that is being designed in-house by Orbital ATK.
The C-600 first stage will produce a maximum of 2.2 million pounds thrust and the second stage C-300 will produce a maximum of 875,000 pounds thrust during flight.
The SRB segments for NGL will be roughly the same diameter as the SRB segments used during the Space Shuttle program as well as those that will be used for SLS; however, NGL’s SRB segments will be slightly longer and heavier than their Shuttle and SLS counterparts.
The added weight will come from additional propellant inside the segments, as the segments themselves will be made of a new, lighter weight and stronger composite material compared to the steel casings used for Shuttle and SLS. The creation of the NGL composite SRB segments – as well as their propellant casting – is also switching to a more automated process, a change that will help reduce the cost of production for the SRB segments while capitalizing on new technologies that have emerged since the Shuttle SRBs were first designed in the 1970s.
We’re currently in the process of going through verification efforts on the case design. Initial testing of a single segment is done and we’re in the process of going through load testing,” noted Mr. Laidley. “Later this year we’ll pour an inert motor that will verify our ability to put propellant in a case segment. All that leads up to static fire testing in 2019 for those solid motor products. So by the time we get to the third quarter of 2019, we will have static fired both the C-300 and C-600 stages,” said Mr. Laidley.
The new design will capitalize on Orbital ATK’s – and their various former companies’ – history of producing SRBs since the 1970s and will include a rigorous test regime to ensure the SRB segment designs are capable of withstanding all of the possible flight environments they will encounter during operation.
“We have in our solid propulsion design and production activities a long history of designing solid motors. And we have processes setup to qualify for maximum environments and maximum scenarios where we can predict what the thermal environments are, what kind of heating all these components are going to see, and what kind of vibrations and shock environments they’re going to experience,” stated Mr. Laidley.
This will include subjecting the segmented design to significant amounts of pressure and temperature differential tests as well as load testing to verify flight environments and qualification for flight. “At the component and subsystem levels, we put these motors through some pretty severe paces, and we design in margins of safety so that we are very confident that they are going to perform reliably over all the mission scenarios we’re going to have to fly,” noted Mr. Laidley.
This robust test environment will include all of the lessons learned from the 30+ years of SRB operation for the Space Shuttle, including post-Challenger SRB redesign testing undertaken by Morton Thiokol – predecessor to ATK and Orbital ATK – that intentionally introduced defects into SRB segment O-ring field joint seals to see exactly how far hot gas would penetrate into the field joints of two SRB segments under different temperature and pressure environments.
Understanding how the SRB field joints perform under these various conditions is vital to the ground testing and development arena for NGL as the rocket’s segmented SRB stages will not be recovered for evaluation of in-flight performance – something Orbital ATK is already familiar with in SRB design as NASA’s SLS rocket will utilize expendable segmented SRBs instead of recoverable ones.
Once the overall design of the SRBs is certified, NGL will debut in its intermediate configuration in 2021. The intermediate variant of NGL can also include strap-on GEM-63XL solid rocket motors produced by Orbital ATK to provide additional lift capacity for LEO or GEO missions.
Three years after the initial introduction of NGL, Orbital ATK plans to introduce the NGL heavy variant, consisting of a four-segment SRB first stage, known as the C-1200, a single-segment SRB second stage, the C-300, and a slightly larger LOX/LH2 upper stage – 110,000 lbs of propellant instead of 70,000 lbs.
In the heavy configuration, meant to fly the same types of missions ULA’s retiring Delta IV-Heavy currently flies, the first stage four-segment SRB would produce roughly 3.1 million pounds of thrust during flight. While both the intermediate and heavy NGL configurations will fly with a 5 meter diameter payload fairing, the heavy configuration payload fairing will be roughly 20 feet (6.09 meters) longer.
Utilizing Kennedy Space Center resources:
To introduce NGL to the government and commercial markets, Orbital ATK will launch the certification flights and initial three years worth of missions from LC-39B at the Kennedy Space Center, sharing the launch pad with NASA’s SLS rocket.
“We have been working closely with the KSC agreements office and the management at KSC to outline a strategy where NGL can co-process along with SLS over the time frames allowed,” said Mr. Laidley. “And SLS has a fairly low launch rate, so we don’t see a huge concern with deconflicting our activities with SLS. We are certainly working with NASA KSC and with the FAA (Federal Aviation Administration) to make sure that we lay out processes that are safe for everyone so that we can all use those vital government facilities as efficiently as possible.”
In addition to sharing LC-39B with SLS, Orbital ATK already have agreements in place to take ownership of MLP-3 – Mobile Launch Platform 3, previously used for the Apollo and Shuttle programs – and modify it for use by both the intermediate and heavy NGL variants as well as for use of High Bay 2 of the Vehicle Assembly Building (VAB) for stacking and integration of NGL before rolling out to Pad-B.
High Bay 2 was utilized in the Shuttle program for External Tank pre-mate inspections and configuration. Beginning in the 2000s, High Bay 3 was configured to serve as a storage High Bay for a complete Space Shuttle stack in case a vehicle at the pad needed to return to the VAB for safe haven from an approaching hurricane at a time when both of the stacking High Bays – High Bays 1 and 3 – were occupied.
The only fully assembled Space Shuttle stack to take residence in High Bay 2 was STS-106/Atlantis, which after stacking and integration operations in High Bay 1 was rolled around the VAB into High Bay 2 for fit checks. No Shuttle stack ever needed to take refuge in High Bay 2 for a hurricane.
MLP-3 and High Bay 2 reconfigurations for NGL are expected to begin in late-2019 and will only begin once NGL has passed through both its Preliminary Design Review in summer 2018 and its Critical Design Review in summer 2019.
However, Orbital ATK is already in contact with contractors in Florida who have current and prior experience building and reconfiguring Mobile Launch Platforms and the VAB High Bays so that once NGL completes its CDR next year, reconfiguration work on MLP-3 and High Bay 2 can begin in earnest.
As for deconflicting operations with SLS, one thing that will greatly aid that endeavor is the extremely limited amount of time NGL will spend on the pad between rollout and launch. “We envision a scenario where we can get down to a very short amount of time on the pad. I think we’re talking on the order of a day or two on the pad from the time we arrive after rollout to when we’re ready to launch and get off the pad and then bring our MLP back,” noted Mr. Laidley.
Nonetheless, the Kennedy Space Center is not the only location NGL will launch from. The vehicle is also designed to serve national security, government, and commercial polar orbit needs via launches from Vandenberg Air Force Base, California.
Currently, Orbital ATK states they have no specific plan and no agreement in place for which launch facility they will use at Vandenberg; however, their ideal plan would be to take over SLC-6 from United Launch Alliance once the last Delta IV-Heavy flies from that pad in 2023.
“We’re working with the Air Force to see if there’s an opportunity for us to step in when ULA leaves [SLC-6] and utilize that facility. That’s one of the options that works for us and our timeline for a first Vandenberg launch in 2024,” said Mr. Laidley.

Oldfart1939 · 2018-04-07 22:40:46

If Elon really gets his s**t together, many of these second generation launchers are going to be conceptually obsolete even before built. But as in times past--his enthusiasm sometimes supersedes time lines for realization. I'd love to hear of short hop test flights by the BFS next year, but am not holding my breath...

RobertDyck · 2018-04-08 02:21:06

How would Falcon Heavy compare to this?

Oldfart1939 · 2018-04-08 09:05:12

Robert-
Not enough information given in the above synopsis of the NGL...
I suspect that reusability of Falcon Heavy components would make it more financially attractive than yet another throwaway system. Maybe reference back to the Ares I-X data at the NASA web site would be somewhat revealing? According to a friend at NASA/Ames, the Ares I was doomed by the overweight Constellation/Orion spacecraft, as well as severe vibration issues (referred to as "pogo-stick vibrations"). I initially thought this SRB first stage concept could certainly reduce the cost to ISS--if indeed, it could be made to work reliably.

GW Johnson · 2018-04-08 10:24:59

Hard to say what the pogo-stick vibration issue is or was. I never kept up closely enough to learn. There was such an issue with the first Saturn-5 flight or two. So there is some sort of pogo-stick instability mode in liquid rockets. But I'm not at all sure it's a commonly-occurring risk.

For solids, that kind of vibration almost has to be longitudinal combustion instability in the motor. That is a quarter-wave "organ pipe" oscillation mode, and a fundamental frequency, not an overtone. This is far more common in the non-metallized reduced smoke composite formulations than in the smoky metallized (with aluminum) formulations.

There is something about a chamber filled with tiny condensed-phase particles at around 20% of the total effluent mass that damps such oscillations out. Most (but not all) the time. If metallization doesn't do the job, then you must alter the effective chamber shape geometry, which is complicated by the fact that it is changing drastically with time as the propellant burns.

The easiest (but often least feasible) solution is to change overall L/D to remove the convergence of the natural organ pipe frequency with the frequency of whatever phenomena is driving the oscillation. These are usually unsteady (oscillating) separated-flow zones interacting directly with the energy release of combustion.

The 4-segment shuttle SRB's were bad enough with their thrust oscillations. Lengthening the motor into a 5-segment form brought the organ pipe mode into stronger resonance. That was the source of the huge vibrations seen in the Ares SRB's. I don't know any details about the current SLS SRB designs, but something has changed about the geometry, enough to render the oscillations tolerable.

Could be a length change, or a diameter change, I dunno. But the propellant is the same basic AP-oxidized 20% aluminum composite used all along, and in the same simple cylindrical grain design shapes. My best guess (and guess it is) is that they modified overall motor internal L/D a little bit to shift the organ-pipe mode further from resonance with the vortex-shedding frequencies between the segment grains inside.

A lot of that could be alleviated with longer segments using slotted-tube grain designs, which for the right segment L/D, could be even more neutral-burning than the cylinder designs. That might not be a feasible option, because the current segments are there precisely because the max feasible mix size corresponds to a segment, rather than the whole motor. A single slotted-tube design would have about twice to twice-and-a-half the length of a simple cylindrical segment, with a higher web fraction and volumetric loading. That may be just too big for existing mixers.

Again, I'm just guessing, based on what I saw with real production solid motors of many sizes decades ago. Chances are, the SLS SRB motor makers will never reveal what they did, and why, for fear of bad publicity.

But there is a second message or point to what I have just said above. There is a way to design large solids that are safe and stable, and relatively free of objectionable vibration. You DO NOT get there by over-constraining the design with too-tight overall envelope requirements up front. Which mistake NASA continues to make, because nobody there really knows nearly what they think they know, about designing solids. You have to design-in stability from the start. You cannot effectively treat it as an afterthought.

GW

Last edited by GW Johnson (2018-04-08 10:33:02)

SpaceNut · 2018-04-08 11:26:05

https://spaceflightnow.com/2016/05/27/d … -revealed/

Next Generation Launcher is a launch vehicle concept proposed by Orbital ATK as an EELV replacement program intended for national security and commercial satellites. Next Generation Launcher is similar to the defunct Ares I and Liberty projects, both of which consisted of a five segment Space Shuttle Solid Rocket Booster and a cryogenic second stage.

Ares I would have combined a five-segment SRB with a J-2X powered second stage, while Liberty would have combine a five-segment SRB with the core stage of the European Ariane 5 as a second stage. By comparison, Next Generational Launcher consists of Space Shuttle-derived solid stages with a cryogenic upper stage provided by Blue Origin. It is intended to be launched from Kennedy Space Center LC-39B or Vandenberg Air Force Base SLC-2.

https://www.orbitalatk.com/flight-syste … fault.aspx

https://www.orbitalatk.com/flight-syste … tsheet.pdf

RobertDyck · 2018-04-08 11:27:15

Everything GW said was true of Aries I. However, Shuttle had a pair of 4-segment SRBs attached to a large external tank with 1.5 million pounds of propellant and a 100 metric tonne orbiter plus cargo. All that dampened vibrations from SRBs. Aries I had a tiny upper stage plus Orion; not enough to dampen vibrations. Add the fact that 5-segment SRBs produce more vibrations for the reasons GW just described. They made Orion large and heavy in an attempt to dampen vibrations, but that's not what you want with a spacecraft. SLS works because it again has a very large liquid core stage and upper stage to dampen vibrations. This proposal would bring back "The Stick"? I thought that idea was dead.

SpaceNut · 2018-04-08 11:31:06

Cargo would be fine with the vibration

Oldfart1939 · 2018-04-08 20:24:57

So---my question for GW would be--could we have a "stick" type first stage, if the NASA dimensional/design requirements were NOT in place? Or is this really another blind alley?

SpaceNut · 2018-04-08 21:35:39

Went 8 pages deep to find the topics.

Ares I (CLV) - status

Liberty Launch Vehicle aka Ares I

Lots of good data from when we were looking at the stick for Constellation, then we had the crash of 2008 through to restart years that is gone followed by some more good data under going forward after cancellation. ATK was the developer of the original so they are all up on the longitudinal oscilation as created via the lengthening to 5 segments from 4 and the change of the propellant mix as well.
AS to cost its still unless they have change the model of operation in the 250 million neighborhood for a launch.

RobertDyck · 2018-04-09 00:53:25

At the joint NASA/Senate announcement of SLS, they said SLS block 2 would replace Ares V. And SLS block 1 would replace Ares I. So this "Next Generation Launcher" is direct competition for SLS block 1. Why would Congress spend money to compete with their own launcher?

Oldfart1939 · 2018-04-09 07:44:43

I suspect that they understand that SLS is a boondoggle? The sooner NASA gets some real leadership (Mr. Bridenstine) they will make some hard decisions.

Oldfart1939 · 2018-04-09 07:50:22

The Air Force seems to have a lot of confidence on SpaceX, so this may be another expensive detour for Orbital ATK/Northrup-Grumman? Of course, the redundancy of having 2 systems available is important to national security planners.

GW Johnson · 2018-04-09 07:52:32

To answer RobertDyck's question at the end of post #11: "corporate welfare" for favored contractors (the ones with lots of lobby money).

To answer Spacenut's contention in post #8: there are vibration gee limits for all things, including cargo, and including flight vehicle structures.

To answer Oldfart1939's question in post #9: If you set the thrust but not the motor L/D during initial design, even if you have picked a segment grain design set by max mix size, then it is still possible to build a reliable, safe solid SRB, that is free of these objectionable "longitudinal vibrations". It might have to be shorter and fatter than you really want, but so be it. You verify smooth operation in test before "freezing" the SRB cluster design, something incompatible with compressed, massively-parallel program planning. Solids will always be a rough ride, but they need not shake you to pieces.

An additional comment: It would help in a segmented motor not to misdesign the seals between the segments. The 3 O-ring joint used after Challenger was even less likely to be reliable than the 2 O-ring joint that killed that crew. For a solid rocket, unlike all liquid and clean-gas practice, you are most reliable with only 1 O-ring in each joint, and a wide open small gap in the motor insulation leading to it. This is driven to the correct side of the groove by pressure-testing the entire motor, which is how you achieve reliability all the way down to -65 F soak temperatures!! You need not pressure check at full motor pressure: if it seals at low pressure, it will seal at high pressure. This is verified very early on the development process in hydrostatic testing, long before you ever fire a live motor.

The solid manfacturers know this (or they should). NASA did not, and still does not know this, because nobody there ever actually built and tested a real segmented solid rocket. Segment seals are actually the very same design problem as forward closure and aft nozzle assembly seals. All work most reliably as a single O-ring seal. What works at 4 inch diameter works at 140 inch diameter, and everywhere in between.

You are sealing a very hot dirty gas that is anywhere from from 2 to 20% condensed phase super-hot sandblast material. Condensed phase material particle temperatures do not cool off by expansion; if the chamber temperature is 5500 F, that sand that hits the rubber O-ring will still be 5500 F. You would do well to slow the velocities way down during the pressurization transient, and not to collimate a sandblast stream (by having it eat through an upstream seal at a single point).

What that means design-wise is twofold: (1) use only 1 seal, and (2) use no "pooky" in the insulation gap. You only need a 90 degree turn to interrupt the flame radiation path to the O-ring, and that is usually inherent, as the insulation gap is radial, while the seal joint overlap is axial. At 20% solids, such radiation is intense far beyond anything ever experienced in liquid or clean-gas work. Take it on locally-thickened steel, not rubber. As for steady state heat conduction, the static gas column in the insulation gap is a far better insulator than any "pooky" ever could be. By at least an order of magnitude.

GW

Last edited by GW Johnson (2018-04-09 08:03:32)

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Next Generation Launcher

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