Observations of the site visit team to the Guiana Space Center:

Overall, operation of the Guiana Space Center (CGS) is a rather lean process. With just over 1,660 employees, the relatively small staff is required to accomplish all of the activities of the launch site’s operations.

Of particular note by the Ground Systems Development and Operations (GSDO) site visit team was the fact that all of these technicians are trained to process and launch any of the three vehicle types present at the space center.

These processes include, “maintaining all facilities and equipment, casting solid propellant into the SRBs for the Vega first stage and the Ariane V SRBs (except forward ‘star configuration’ segment), and manufacturing liquid propellant,” notes the Takeaways from Benchmarking Trip to Guiana Space Center presentation – available for download on L2.

Soyuz operations at the CSG are augmented with 300+ personnel who travel from Russia 
during launch campaigns only. The aforementioned 1,660 employees carry out all other Soyuz-related work.

The site visit team noted the complex – yet seemingly mature and effective – organizational structure employed at CGS, with most aspects of vehicle manufacturing and assembly being “geographically distributed to ESA member states.”

When viewed from the Ariane V flow standpoint, the GSDO team found numerous potential learning points for NASA as the agency moves toward realization of the SLS rocket.

In particular, the team outlined the process for integrating and launching the Ariane V rocket.

SRB integration:

Stacked in a separate Booster Integration Facility, a climate controlled building, the Ariane V’s SRB segments are mated together with the use of “movable platforms with emergency exit points at expected levels were booster access is required,” notes the GSDO presentation.

All booster access is carefully planned to occur in the Booster Integration Facility, with no planned access after the Boosters leave for integration with the Core Stage.

Furthermore, at the Kourou launch facility, the SRB segment lifting beams use optical sensors for alignment during stacking operations, thus removing the need for personnel in “cherry pickers” to attach lifting beams to segments -– as was done for the entire 30+ year history of SRB stacking operations at the Kennedy Space Center.

The site team also noted the lack of a water deluge system in the Booster Integration Facility. Discussions with Guiana Space Center officials revealed that “the installation of sprinkler systems is based on risk and… not strictly on code compliance.”

The GSDO report also discussed the incorporation of five accelerometers on each Ariane V SRB for in-flight measurement of thrust oscillation.

However, the largest discussion contained within the report related to the heaters and field joint insulation of the Ariane V’s SRBs versus those on the Space Shuttle-derived SRBs for the SLS rocket.

The GSDO site team presentation notes, “Ariane V SRBs do not have any heaters or installation on their field joints. After segment mate, they install the pins, pin retainer band, and then coat the joints with grease to inhibit corrosion.

““We provide various levels of insulation on our SRB field joints.”

Following this, the team’s presentation discussed the preliminary SLS rocket’s SRB field joint configuration, showing the initial heritage design of the Shuttle SRB field joints with the new design for SLS.

As noted by the GSDO presentation, “design significantly simplified over heritage design with the elimination of joint heaters.””

Additionally, it appears that the RT 455 material will not be required except to fill pull test locations on the new field joints. Furthermore, the cork area around the SLS SRB case segments has been significantly reduced from the design used on Shuttle.

Returning back to the site visit at Kourou, the team noted one final aspect of the SRB environment: that it contained “no FOD elimination requirements “during the tour, even as we leaned within inches of the solid motors.””

Ariane Core Stage integration:

For Ariane V consideration, after the SRB segments are stacked and integrated, they are transported by rail to the Launcher Integration Building.

Here, the Ariane V Core Stage/Upper Stage is mated with the twin SRBs.

By the time the Core and Upper Stages arrive in the Launcher Integration Building for mating with the solid rockets, “the Upper Stage and the launcher’s vehicle equipment bay” have already been pre-integrated on the European continent prior to shipment for South America.

This is done primarily to accelerate the mission launch rate and reduce the amount of time necessary to process both stages at the launch site.

In regards to the core and Upper Stage portions of the vehicle, the site visit team also noted the Linear Shaped Charges (LSCs) that are used in the event of launch mishap.

The LSCs are installed on the Core Stage at its manufacturing site in France. Mechanical inhibits are installed onto the LSCs to prevent accidental detonation during final construction and shipment of the Core Stage to South America.

Once the Core and Upper Stages have been mated to the twin solid rockets, the mechanical inhibitors are removed prior to the vehicle’s roll to the pad.

Electrical inhibits remain in place on the Linear Shaped Charges to prevent accidental detonation during the vehicle’s move to the pad for final countdown and launch operations.

These electrical inhibits are removed while the vehicle is at the pad in a process that does not require physical access to the vehicle, – something NASA is hoping to mitigate with SLS pad operations.

The presentation further noted that both the Ariane V and Vega launch vehicles are “neutralized with LSCs if they go off course.” LSCs are not used on the Russian Soyuz vehicles, however. Instead, the Soyuz is commanded to shut down its engines and is then allowed to fall into a predicted impact location with minimal debris field.

Payload integration and pad ops:

Once the SRBs and Core/Upper Stages are mated together, a vehicle integration test sequence begins. The entire mating and testing operation takes approximately 20 days to accomplish.

Afterward, the main propulsive portions of the vehicle are moved to the Final Assembly Building where the processes of integrating the vehicle with its payload and fueling the Upper Stage storable propellants takes approximately eight days.

The vehicle then makes the 3 km trip to the launch pad where a “no access at pad” approach is employed for the duration of the approximate 12-hour-on-launch-pad operation sequence.

At the pad, two “half wave” T-0 dampener cables are used to “keep the rocket from ‘tipping’ in one direction. The wind always blows in the same direction” at the Kourou Guiana Space Center, according to the GSDO document.

Cryogenic propellant arms attached to the third stage also provide stabilization for the vehicle up to 12 seconds prior to lift off when the arms are disengaged prior to Core Stage ignition.

This kind of knowledge could prove beneficial to NASA in their development of the SLS which, because if its sheer height and in-line design, will require stabilization arms from the launch umbilical tower to keep it from falling over in the windy sea-side environment of the Kennedy launch complex.

Also of note for the Ariane V launch pad were the flame deflector, the sound suppression system, and the handrails at the pad.

Specifically, the team noted that the flame deflector did not have an ablative material, which could result in large potential savings for GSDO if the same approach was used for SLS.

Moreover, the Ariane V sound suppression system was found to be of a much higher caliber than the one employed at the LC-39 launch complex of Kennedy.

As noted by the team, “Water is down stream from the tank well before lift off. Water doesn’t have to travel long distances following release. Two valves in series very close to the nozzles enable water to be released exactly when water is required.”

Finally, the site team noted that the handrails on the Ariane V launch table are permanently mounted. If the same practice could be adopted for SLS, significant time-savings could be realized by not having to remove the handrails prior to launch.

In all, the GSDO team’s site visit to the Kourou, French Guiana launch site for the European Space Agency led to the creation of distinct action items.

These action items include: Confirm the requirement for “clean rooms” during SRB joint mate in the VAB; Review SRB segment re-inspection time requirements; Travel of SLS Booster Element manager to KSC to review GSDO’s step-by-step design viz ops to ensure there are no un-necessary processing requirements; and Explore GSDO use of SLS’s 5-segment inert booster for pathfinder type stacking.

Relating SRB segment re-inspection time requirements, the current requirements state that re-inspections must occur if segments are not stacked within a year following initial KSC inspection (6 months for forward segments) and if segments are not launched within a year of stacking.

(Images: Via L2 content from L2′s SLS specific L2 section, which includes, presentations, videos, graphics and internal – interactive with actual SLS engineers – updates on the SLS and HLV, available on no other site. Other images via Arianespace/ESA)

(L2 is – as it has been for the past several years – providing full exclusive SLS  and Exploration Planning coverage.  To join L2, click here: http://www.nasaspaceflight.com/l2/)

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SLS Progress:

With the Space Launch System deep into its pre-PDR evaluations, the Heavy Lift Launch Vehicle (HLV) continues to avoid the problematic technical issues suffered by the rocket it technically replaced, namely the Ares I from the now-defunct Constellation Program (CxP).

While Ares I had managed to get through the PDR stage prior to its demise, major SLS elements – such as the Core Stage – are already fast approaching the point of maturity Ares I’s Upper Stage had achieved.

As such – and despite a compressed schedule to make its debut launch target in 2017 – SLS is on track and continues to enjoy several months of schedule margin.

Of course, as with any rocket, SLS’ development thus far has not been trouble-free, with engineering teams successfully mitigating problems such as a required change to the slosh baffle design on the core stage.

As noted in L2′s SLS Development Update Section, engineers are also looking at the design of the booster nose cones, due to an aeroacoustic loading issue – in the transonic flight region – impacting on the booster/core attach points, per evaluations.

Initial information points to potentially changing the nose cone design to that seen on boosters used by Ariane 5, or indeed the cone design currently portrayed by ATK’s Advanced Boosters, in order to mitigate the issue.

Notably, per all recent information, none of SLS’ challenges have resulted in a major concern on its report cards, unlike Ares I’s troublesome childhood.

A huge amount of work has already taken place at the pre-PDR level, with some elements of the Core Stage already eyeing the next big milestone – the Critical Design Review (CDR) in 2015.

The depth of the PDR can be seen via one status update that noted one department’s “data pack” consisted of over 300 documents – 200 of which were created for the Interim Cryogenic Propulsion Stage (ICPS) by Boeing/United Launch Alliance (ULA) – before being sent for review at five NASA centers.

Per L2 information, the review of that PDR data pack – for the Spacecraft and Payload Integration Office (SPIO) – is now complete, with the reviewers adding what are known as candidate Review Item Discrepancies (RIDs).

A series of meetings have now begun to evaluate and categorize the RIDs, via a complex process that will last as late as June 14. The disposition of the RIDs will be reviewed by the SPIO PDR Pre-Board on June 20, and final approval of all RID dispositions will be completed by the PDR Board on June 27.

Following the Board meeting, document developers will begin the process of implementing the RIDs in the documents.

Meanwhile, the data pack for the SLS PDR was released to reviewers on Friday (May 31). The reviewers have until June 28 to submit candidate RIDs.

The formal “kick off” for the SLS PDR is on track for June 18-19.

For previous SLS Articles, click here: http://www.nasaspaceflight.com/tag/hlv/

Once the PDR is complete, all SLS elements will progress towards the CDR. Two more review milestones will follow ahead of the debut launch of the SLS, with the Design Certification Review (DCR) followed by the Flight Readiness Review (FRR) – the latter ensuring all open items from DCR are closed out prior to flight.

Evolved SLS via the PDR:

Per L2 information, one of the documents in the SLS PDR data pack is the “Evolvability Report”, which is a technical evaluation for potential development paths by which the Block 1 SLS can be “evolved” to its full capability, as required by Congress.

SLS will initially launch as a Block 1 vehicle, with a 70mT capability, conducting the opening salvo of Beyond Earth Orbit (BEO) adventures, such as Exploration Mission -1 (EM-1), an uncrewed mission to send Orion on a test flight around the Moon, and Exploration Mission -2 (EM-2). which involves sending a crewed Orion on a mission to meet up with a captured asteroid in the vicinity of the Moon.

By the mid-2020s, SLS will evolve to a Block 1A vehicle with a 105mT capability, using Advanced Boosters, utilizing either Solid or Liquid fueled options. A Block 1B option may also be available, with a 118mT capability, as explained later in the article.

The final evolution will be to the Block 2 SLS, which is classed as the flagship launch vehicle for crewed missions to Mars.

While the Evolvability Report is nothing more than a technical evaluation for decision makers – and does not represent any actual decisions by NASA for future SLS development – it does provide an interesting insight into SLS’ growth options.

Option 1 begins with development of the Advanced Boosters, followed by the use of the J-2X Upper Stage, the increase to five RS-25E engines on the Core Stage, prior to the addition of a five meter diameter Cryogenic Propulsion Stage (CPS).

Option 2 also begins with development of the Advanced Boosters, followed by the five meter CPS, then the J-2X Upper Stage, and finally move to a five engine Core Stage.

Option 3 takes SLS along a different path, with the development of a Dual-Use Upper Stage (DUUS – pronounced “Duce”), followed by development of the Advanced Boosters.

Per L2 information, each of the options were evaluated for their “mission capture” attributes, or how soon each of the Design Reference Missions (DRM) maintained by the Human Architecture Team (HAT) are enabled by the increased capability of the SLS via each improvement – such as the increase in payload capability when the Advanced Boosters debut with the HLV.

While the HAT are still working on the future missions, from EM-3 onwards, the SLS Evolvability Report concludes that Option 3 achieves the best “mission capture” results, followed by Option 2.

The finding adds yet more weight to source notes over recent years that the J-2X is by no means assured of a role with the SLS.

Expanding on the DUUS option, this stage – driven by up to four RL-10 engines – would be tasked with completing the ascent phase of the SLS after Core Stage burnout, before then operating as an In-Space Stage – hence, the “dual use” tag – to conduct the Trans-Lunar Injection (TLI) burn for an Orion spacecraft, coast to the Moon and conduct the Lunar Orbit Injection (LOI) burn.

Then, after Orion separates, it would conduct a disposal maneuver to crash the stage into the Moon.

The DUUS was studied in three possible configurations, namely the 8450, 8455, and 8463 models. Each configuration consists of an 8.4-meter diameter LH2 tank and LOX tank – the latter with diameters of 5.0, 5.5, and 6.3 meters, respectively.

The 8450 model would be able to take advantage of existing manufacturing capabilities for the construction of the LOX tank, as such this model is expected to be the cheapest to produce.

However, the 8463 model is the shortest of the three configurations, which would allow for the optimum payload height during integration processing inside the Vehicle Assembly Building (VAB).

Follow on information notes the advantages of an 8.4m DUUS on an 8.4m core includes the potential for a common bulkhead between LOX and LH2 tanks, and – in addition to the high efficiency engines – this should equate to less stage dry mass, resulting in additional payload up-mass capability.

Documentation from 2012 also pointed towards the evaluations into using the RL-10 driven stage, showing the SLS Block 1B, using Five Segment Boosters, resulting in an up-mass capability of 118mT to Low Earth Orbit (LEO) and 43mT to Beyond Earth Orbit (BEO).

The information also shows the SLS Block 2 – again with the 8.4 meter diameter 4xRL-10 stage – with Advanced Boosters, allowing for an up-mass capability of 155mT to LEO and 61mT to BEO.

While the forward path for evaluating all of the options will result in no immediate decisions, the “Duce” is already being cited as a large money-saver, not least because it would likely allow SLS to remain with its four RS-25E’s on the core stage, removing the redesign requirements to move to a five engine core when SLS evolves.

Further articles will follow during the PDR process.

(Images: Via L2 content from L2′s SLS specific L2 section, which includes, presentations, videos, graphics and internal – interactive with actual SLS engineers – updates on the SLS and HLV, available on no other site. Other images via NASA and ULA)

(L2 is – as it has been for the past several years – providing full exclusive SLS  and Exploration Planning coverage.  To join L2, click here: http://www.nasaspaceflight.com/l2/)

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SLS Five Segment Booster:

Following the success of the three static fire tests of the five segment motor that was initially set to launch Ares I – before being re-purposed for the SLS – ATK are now deep into their preparations for the next major milestone, the Qualification Motor -1 (QM-1) test, which is set to take place at the end of this year.

The three Demonstration Motor (DM) firings provided a vast amount of data on the longer version of the booster that became famous during the Space Shuttle Program (SSP), with the most recent test – DM-3 – being the most heavily instrumented solid rocket motor in NASA history, with a total of 37 test objectives measured through more than 970 instruments.

The results of the DM tests have allowed ATK to complete the booster’s Preliminary Design Review (PDR) in conjunction with NASA, a milestone review that was conducted well within the planned schedule path for the opening SLS launch in 2017. The booster element for SLS currently enjoys around one year of margin.

The opening SLS mission, known as Exploration Mission -1 (EM-1), will involve two of the new five segment motors heading to the Kennedy Space Center (KSC) for Booster Integration (BI) processing, with the flow almost mirroring that used during the 30 year career of the Space Shuttle.

Click here for 100s of News Articles on the SRBs: http://www.nasaspaceflight.com/tag/srb/

“The booster PDR was successful and speaks to the importance of a collaborative design process with our NASA customer” noted Fred Brasfield, ATK vice president, Next-generation Booster.

With the successful completion of PDR, the SLS booster team at ATK can now advance the design toward the Critical Design Review (CDR). This review will come after the next static fire involving QM-1.

Despite a slight slip in the schedule – mainly related to an issue with the aft segment of the QM-1, which was found to have about a two foot-wide area where propellant had debonded from the inside of the segment wall – the QM-1 segments are now building up at the test site at Promontory, Utah.

At present, engineers have both the forward and center segments being placed into position at the home of the booster test firings.

SLS Advanced Booster:

The five segment boosters will continue to provide the bulk of SLS’ launch power during first stage flight through into the second half of the 2020s.

Following that, SLS will receive an additional boost via the addition of “Advanced Boosters”, enabling SLS to evolve to a launch vehicle capable of lofting 130mT of payload – deemed a requirement for missions to Mars.

Several companies are in the early stages of developing their proposals under NASA’s SLS Advanced Booster Engineering Demonstration and/or Risk Reduction (ABEDRR) procurement, ranging from solid to liquid options – such as Dynetics Inc./Pratt & Whitney Rocketdyne (PWR), who are proposing the use of the famous Saturn V F-1 engines to advance SLS’ capability to launch payloads of up to 150mT to orbit.

ATK’s own proposal – as outlined in a presentation acquired by L2 – builds on their legacy with the four and five segment boosters, with a motor that is “advanced” on several levels, by “provid(ing) NASA the capability for the SLS to achieve 130 mT payload with significant margin, utilizing a booster that is 40 percent less expensive and 24 percent more reliable than the current SLS booster.”

Click here for SLS News Articles: http://www.nasaspaceflight.com/tag/hlv/

The company’s proposal includes a higher ISP density of the propellent, boosting payload performance by nearly 25,000lbm, yet saving $9.2m in costs per booster. With the increased operating pressure, improved propellant, tailored thrust profile, increased expansion ratio all combine to provide a 15.1mT boost to the SLS’ payload capability.

Around six months into the development process, ATK’s Advanced Booster NASA Research Announcement (NRA) team is working to overcome key technological challenges and reduce the overall risk posture of an Advanced Booster.

According to ATK, some of the current Advanced Booster tasks are being worked on by the Propellant/Liner/Insulation (PLI) Integrated Product Team (IPT), who are tackling the challenge of developing a high-performance, low-cost PLI system.

Not unlike testing different mixes of paint at a hardware store, the PLI IPT are busy establishing a design of experiments (DOE) matrix, cooking up 66 unique propellant mixes to test candidate propellant formulations for burn rate performance and mechanical property characteristics.

ATK note that several “families” of solid propellant formulations are being evaluated in the DOE, with multiple variations within these families undergoing testing to select the best formulation within each family to pursue further testing within larger scale mixes.

The team working on the mixes include expert propellant chemists Ingvar Wallace, Jay Shuler and Michael Smith, who are attempting to select the best mix by the early part of this summer, ahead of the favored propellant formulation being tested in the NRA’s 92-inch diameter integrated static test in early 2015.

Lead Image: Screenshot from the amazing 220mb super slow-mo DM-3 Five Seg Motor Ground Test Video -  available in L2 – LINK).

(Other Images: Via ATK, NASA and L2 content from L2′s SLS specific L2 section, which includes, presentations, videos, graphics and internal – interactive with actual SLS engineers – updates on the SLS and HLV, available on no other site.)

(L2 is – as it has been for the past several years – providing full exclusive SLS and Exploration Planning coverage. To join L2, click here: http://www.nasaspaceflight.com/l2/)

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SLS SMAT:

Continuing the heritage of testing future launch vehicles at the scale model level, NASA engineers have test fired scaled versions of rockets to gain data on the acoustic environments endured during ignition and launch.

The primary source of the acoustic field is the fluctuating turbulence in the mixing region of the rocket exhaust flow – known as Engine Generated Acoustics.

Engine generated noise is a function of the exhaust flow parameters, launch stand configuration, and to a lesser extent atmospheric conditions.

Preliminary estimates of the engine generated acoustics at a specified location on the vehicle can be determined by scaling measured acoustic data from previous launch vehicle programs, taking into account the above mentioned flow, configuration, and atmospheric parameters.

A better definition of the lift-off acoustic environment can be determined from hot fire testing of dynamically scaled models of the launch vehicle and stand.

During the Space Shuttle development program, a 6.4 percent scale model of the launch vehicle, propulsion system, launch stand, and exhaust duct system with water suppression was used to refine the analytical/scaling estimates of the lift-off acoustic environment.

The resulting data provides a very useful template for the full scale rocket, although final verification of the environment is only fully provided by full static firings or launches of the actual vehicle.

Notably, the debut launch of the Space Shuttle Program (SSP) – with Columbia on STS-1 – showed the importance of understanding the acoustic environments, as the orbiter’s heat shield was damaged when an overpressure wave from the SRBs caused a forward RCS oxidizer strut to fail. Her body flap was also pushed five degrees out of position.

The subject was also raised during STS-129′s Flight Readiness Review (FRR), as a potential issue with a very small area of the orbiter – known as a stinger attach point between the RCS and OMS Pod – raised concerns that recent acoustic environment analysis of the Space Shuttle Main Engines (SSMEs) during ignition could cause stressing that potentially leads to cracks in the attach pins/stinger.

Although those concerns were based on old and overly conservative data, managers showed their usual due diligence in gathering an array of updated information, via new computational models, borescope inspections on the fleet, and the installation of sensors in the area in question – all of which would be used to completely allay the potential fear of life fatigue on the stinger.

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Notably, the FRR presentations noted they lacked key historical data, given the 6.4 percent model tested during the 1970s only fired motors that mimicked the Solid Rocket Boosters and not the SSMEs, while Main Engine Ignition (MEI) Acoustic & SSME Ignition Overpressure (IOP) Environment data was classed as “continually evolving” during the 30 years of the program – leading to the concern ahead of STS-129.

The vehicle that was set to replace the Space Shuttle, Ares I, also underwent IOP testing – with the Ares I Scale Model Acoustics Test (ASMAT) tested during 2010.

Numerous tests, each using a different pad configuration – such as with and without water bags within the launch mount – were conducted at MSFC.

Quick look test results indicated that the overall noise levels measured on the vehicle were within predicted ranges and the data compared favorably between the firings. However, Ares I was cancelled shortly after the ASMAT firings.

With the SLS now providing the role of NASA’s flagship launch vehicle, the Heavy Lift Launch Vehicle (HLV) will enjoy its turn on the test stand for the acoustic environmental tests – known as Scale Model Acoustic Test (SMAT).

Work begin in 2012 at Marshall’s test stand 116, with the construction of a working water-based sound suppression system.

“This water system will be used during the planned hot fire testing series that is planned for SMAT, which utilizes small-scale solid rocket Boosters and Lox-Hydrogen thrusters,” noted L2′s rolling SLS updates.

“Based on discussions with NASA/KSC Ground Systems Development and Operations (GSDO) engineers, MSFC is satisfied that this properly represents the water flow rates and coverage of the full-scale system and will meet the test needs for SMAT.”

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As with the tests on the previous vehicles, the data will provide a good baseline ahead of the actual SLS firing into life later this decade.

Notably, the SMAT will involve the most technically advanced sub-scale rocket used on such a test.

“Ignition overpressure (IOP) is a significant transient low-frequency pressure event caused by the rapid pressure rise rate of the solid rocket motor,” opened an extensive presentation on the SMAT (L2). “Lift-off acoustics (LOA) noise is caused by the supersonic steady jet flow interaction with surrounding atmosphere and launch complex, persisting for 0-20 seconds as the vehicle lifts off.

“Scale Model Acoustic Test (SMAT) objectives: Verify predicted LOA environments, obtain data to update the lift-off acoustic environments. Verify predicted IOP environments, obtain data for use in IOP analytical models for updated environments, and improve IOP analytical models.

“Verify SLS deflector design. Characterize Ground Acoustic (GA) environments, provide data to support GA environment predictions. Obtain Spatial Correlation (SC) data for use in vibro-acoustic models. Obtain data for Computation Fluid Dynamics (CFD) validation, and evaluate water sound suppression systems, determine water suppression attenuation.”

Obviously, engineers won’t be able to literally scale down the SLS’ RS-25 main engines or five segment SRBs, so alternative motors will be used on the SMAT model.

As such, two Rocket-Assisted Take Off (RATO) motors will simulate SLS boosters, with the test requirement calling for the motors ignite simultaneously, as the SRBs would during launch.

Testing has already begun on the small thrusters that will provide the role of the four RS-25 liquid main engines on the core.

A single thruster – similar to vintage hardware originally designed in the 1960′s and tested during the Space Shuttle program – successfully met all test objectives during Phase I scale model acoustic testing last year at Marshall’s Test Stand 115.

Fabrication then began for a “fourthruster cluster” set, mirroring the four RS-25s that will power all versions of SLS’ core stage.

“Hot-fire testing was initiated for the thrusters that will simulate the Core Stage Engines for the Scale Model Acoustic Test (SMAT). All four thrusters have been tested together for the first time in a single cluster in the same configuration that will be used for the Core Stage of the SMAT model,” added SLS’ rolling update section (L2).

“Testing is being conducted at Test stand 115 in the Marshall Space Flight Center (MSFC) East Test area. The first start ignition test was conducted on March 7, 2013. Two low thrust main stage tests were conducted on March 8, 2013. All test hardware is in excellent condition so far and (will continue testing during the Spring).”

When the actual SMAT model is completed and integrated on the test pad, a number of tests can be expected, not least because the maximum lift-off acoustic environment during an SLS launch will not be endured in the vehicle starting position, but at some elevation above the Mobile Launcher.

As such, tests will probably attempt to simulate a lift-off, without the SMAT model actually launching.

For the Ares I Scale Modelling Acoustic Tests, the vehicle model was set at a number of fixed elevations for individual test firings, these being 0, 2.5, 5.0, 7.5, and 10.0 feet. Based on the scale of the ASMAT, these distances corresponded to full-scale elevations of 0, 50, 100, 150, and 200 feet.

Also, as expected, the test vehicle will be heavily instrumented, with five primary instrumentation suites resulting in over 325 sensors on the SMAT rocket.

It will be outfitted with B&K 4944-B microphones, pressure transducers on the tower/mobile launcher. It will include far field measurement devices, accelerometers, thermocouples and strain gauges on vehicle, thermocouples, flow meters and chamber pressure instrumentation.

The first test fire is expected to take place either in the summer of fall of this year.

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ATK Five Segment Testing:

Since increasing the length from a four segment Reusable Solid Rocket Motor (RSRM) used by the Space Shuttle – to 154 foot long five segment booster that will ride with the Space Launch System (SLS) – a mid-span support was deemed necessary to decrease the sag in the test motor as it finds itself firing in the “usual” horizontal position.

The tests – originally for the Ares 1 first stage – have been realigned ahead of their use on the SLS, which will debut at the end of 2017 as the Block 1 configuration.

This initial capability Heavy Lift Launch Vehicle (HLV) will consist of a core stage using four Pratt and Whitney Rocketdyne (PWD) RS-25Ds – formerly used by the Shuttle Program – two ATK five segment Solid Rocket Boosters (SRBs) and an Interim Cryogenic Propulsion Stage (ICPS), highly likely to be a Delta Cryogenic Second Stage (DCSS).

Three static fire tests have already taken place on the five segment boosters, all with a single span located in the middle of the booster.

The most recent test – DM-3 – took place in 2011 and was the last in a series of development motors to be tested. It was also the most heavily instrumented solid rocket motor in NASA history, with a total of 37 test objectives measured through more than 970 instruments.

(Image taken from the amazing 220mb super slow-mo DM-3 Five Seg Motor Ground Test Video – available in L2 – LINK).

The previous test – DM-2 in 2010 – was carried out with a total of 53 design objectives, measured through more than 760 instruments. For that test, the motor was cooled to 40 degrees F – a “cold motor” test – in order to measure solid rocket motor performance at low temperature, as well as to verify design requirements of new materials in the motor joints.

The DM-3 incorporated several performance-based improvements to the designs of the first two development motors. Additionally, the core of DM-3 was heated to 90 degrees Fahrenheit for this full-duration firing to verify the motor’s performance at high temperatures.

ATK are already deep into preparations for the first qualification firing of the five segment booster, with QM-1.

It is expected that the five segment solid motor will be used on all SLS flights until at least the middle of the 2020s, with source information noting SLS managers have the option to launch up to 10 missions using the current five segment booster design.

QM Mid Span Supports:

QM-1 – and the follow on QM-2 – will both be fired at ATK Propulsion Systems base in Promontory, Utah. However, there will be a visual difference from previous firings, with the debut of two mid-span supports to further decrease motor sag to more closely simulate a vertical flight motor.

After ATK determined the need for a second mid-span support, they contracted with the same vendors that fabricated the first mid-span.

The three major vendors for mid-span support include Major Tool and Machine from Indiana, Force Measurement Systems (FMS) of California, and Specialized Analysis Engineering (SAE) of Utah.

The mid-span structures include two uprights bolted to the floor and a structure that spans the width of the static test motor and supports the weight taken up by the slings during build-up and testing.

The engineers at FMS manufactured the structure load cells and flexures used to support the sling, while the SAE team designed and built the control system for the support.

SAE are currently in the process of wiring and programming the control system - just as they did with the first mid-span support used for the DM static test motors.

The system uses a custom programmable logic controller to control the electric motors and also receive load cell data.

“These suppliers have a long-standing history with ATK and have once again proven their worth as deserving partners. We appreciate their ability to perform as required,” noted Fred Brasfield, vice president, Next-generation Booster.

“These vendors have supplied the components and structures needed to help obtain necessary data from our test motors.”

QM-1 Delay:

Preparations for the upcoming QM-1 test began with the first casting operation of the Forward Segment back in July 16, 2012 at ATK’s Promontory facility.

Casting operations continued without issue, with the Center/Forward segment casting operations beginning in August of 2012.

SLS L2 Update Section did, however, note a few issues that had to be worked during the development schedule, one relating to the replacement of the ultrasonic sensor instrumentation in the QM-1 nozzle, and another involving the new over/under speed protection (GTx) feature of the Electrical Ground Support Equipment (EGSE).

“A continuity failure of one sensor following nozzle assembly initiated an investigation revealing out of spec connector assemblies to several sensors. The decision has been made to re-terminate all 20 ultrasonic sensor connectors and re-assemble the Nozzle,” noted the updates.

“The second issue – specific to the GTx – relates to flight acceptance testing. The early development of the GTx allows multiple hot-fire exposures prior to deployment to KSC and buys down significant flight schedule risk. Initial testing of the GTx revealed an unacceptable sensitivity to noise, which will required modification.

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The GTx design was then verified during a hot-fire dry-run known as the Flight Control Test -2 (FCT-2), which took place earlier this year.

This key avionics and controls test included a “hot fire” of the fully integrated heritage TVC (Thrust Vector Control), the new SLS booster avionics subsystem and new EGSE.

The test – of which an impressive video was made available – showed the TVC’s systems purring into life during the FCT-2 countdown, prior to the actual firing of the SRM Ignition Initiators at T-0, simulating an actual lift-off. This was followed by the TVC systems gimballing the nozzle (not in place) on the hot fire aft skirt.

“The FCT-2 test marked a definite milestone for ATK and NASA’s SLS program,” added Mr Brasfield. “Working with Marshall, we have designed and developed a modern system and common interface that allows for multiple uses of the same equipment at all necessary locations for both qualification and operational phases of the program, greatly reducing complexity and costs.”

QM-1 had already slipped from its initial schedule of conducting the static test in May by the time of the FCT-2 success, with the latest estimate showing the firing of the QM-1 will be no sooner than November.

The slip to the end of the year is in part related to an issue with the aft segment of the QM-1, which was found to have about a two foot-wide area where propellant had debonded from the inside of the segment wall.

After some analysis – which found no voids in the actual propellant – NASA decided to ask ATK to scrap the segment and cast a replacement.

The delay holds no impact on the schedule for the second static test – QM-2 – or the schedule towards the EM-1 flight in 2017, due more than a year of margin.

(Images: Via ATK and L2 content from L2′s SLS specific L2 sections, which includes, presentations, videos, graphics and internal – interactive with actual SLS engineers – updates on the SLS and HLV, available on no other site.)

(L2 is – as it has been for the past several years – providing full exclusive SLS and Exploration Planning coverage. To join L2, click here: http://www.nasaspaceflight.com/l2/)

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ATK’s Heritage:

With a 30 year history in providing the boosters for the Space Shuttle Program (SSP), ATK’s solid motors boast a huge knowledge base.

As seen in Flight Readiness Review (FRR) and post mission In Flight Anomaly Review (IFA) documentation, the four segment boosters – like the rest of the “Shuttle Stack” – ended their career in style, with the aforementioned documentation providing an impressive report card on their performance and lack of issues.

It was also notable that ATK continued to refine and tweak the motors during the final flights, with one example being the redesign to the SRB Thrust Vector Control (TVC) Auxiliary Power Unit (APU) fuel pump for the final three Shuttle missions, removing a “critical 1″ failure scenario that held the small potential of a LOV/C (Loss of Vehicle/Crew) event.

While the boosters are continuing to evolve, the huge legacy of their role with the Space Shuttle will directly feed into their use on the SLS – a Shuttle Derived (SD) Heavy Lift Launch Vehicle (HLV).

ATK Boosters with SLS Block 1:

The SLS will debut at the end of 2017 as the Block 1 configuration consisting of a core stage using four Pratt and Whitney Rocketdyne (PWD) RS-25Ds – formerly used by the Shuttle Program – two ATK five segment Solid Rocket Boosters (SRBs) and an Interim Cryogenic Propulsion Stage (ICPS), highly likely to be a Delta Cryogenic Second Stage (DCSS).

Three static fire tests have already taken place on the five segment boosters, as the motor transferred its service from the now-defunct Ares 1′s first stage to SLS.

The latest test – DM-3 – took place in 2011 and was the last in a series of development motors to be tested. It was also the most heavily instrumented solid rocket motor in NASA history, with a total of 37 test objectives measured through more than 970 instruments.

(Image taken from the amazing 220mb super slow-mo DM-3 Five Seg Motor Ground Test Video – available in L2 – LINK).

The previous test – DM-2 in 2010 – was carried out with a total of 53 design objectives, measured through more than 760 instruments. For that test, the motor was cooled to 40 degrees F – a “cold motor” test – in order to measure solid rocket motor performance at low temperature, as well as to verify design requirements of new materials in the motor joints.

Click here for SRB Articles: http://www.nasaspaceflight.com/tag/srb/

The DM-3 incorporated several performance-based improvements to the designs of the first two development motors. Additionally, the core of DM-3 was heated to 90 degrees Fahrenheit for this full-duration firing to verify the motor’s performance at high temperatures.

ATK are already deep into preparations for the first qualification firing of the five segment booster, with QM-1 set to take place in May, 2013.

It is expected that the five segment solid motor will be used on all SLS flights until at least the middle of the 2020s, with source information noting SLS managers have the option to launch up to 10 missions using the current five segment booster design.

ATK Advanced Booster:

The forward path for SLS is to evolve from the 70mT HLV into the 105mt – known as the Block IA – before eventually advancing into the 130mT Super Heavy launcher known as the Block II.

As part of enabling this evolution, a competition will decide between numerous proposals that will create an “advanced booster” option for SLS, which will be implemented on the Block 1A (or Block 1B – depending on the configuration), prior to its role with the Block II from its first launch.

One such proposal – which is currently being worked on under NASA’s SLS Advanced Booster Engineering Demonstration and/or Risk Reduction (ABEDRR) procurement – was reported on by this site after Dynetics, Inc. and Pratt & Whitney Rocketdyne (PWR) formed a team “to offer an affordable booster approach that meets the evolved capabilities of the SLS” – and presented their overview at the 63rd International Astronautical Congress, Naples, Italy in October, 2012.

Their liquid booster approach – using the baseline of the famous Saturn V F-1 engines – claims they could advance SLS’ capability to launch payloads of 150mT to orbit.

ATK’s proposal – outlined in a presentation acquired by L2 – builds on their legacy, with a motor that is “advanced” on several levels, by “provid(ing) NASA the capability for the SLS to achieve 130 mT payload with significant margin, utilizing a booster that is 40 percent less expensive and 24 percent more reliable than the current SLS booster.

“Some of the characteristics of the Advanced Booster include features that have been identified by NASA as important for the next-generation booster are: an energetic propellant to improve performance and reduce cost, a composite case using low cost fiber/resin, electric Thrust Vector Control (TVC), and an adaptable core attach design to minimize interface concerns.”

ATK cite advanced manufacturing techniques and streamlined processes – combined with an innovative design that includes the nose cone reshaped to reduce aerodynamic loads on the core stage – as a major part of the 40 percent reduction in costs when compared to the five-segment SRBs.

The advanced booster will utilize composite casing with low cost, high strength fibers – represented as black casings in notional graphics.

ATK are also proposing to reduce the number of segments – back to four – to improve processing at launch site, along with simplified forward and aft structures and increased comparability with the overall vehicle avionics architecture.

A key line in the presentation cites the Advanced Booster “will provide 42 percent of SLS vehicle impulse while making up only 18 percent of the total vehicle propulsion cost.”

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Charts provided in the presentation expand on areas where performance will be improved, all while reducing costs when compared to the five segment motor.

This can be clearly seen in examples such as the use of the composite casings, which provide a 4,128lbm payload capability improvement. The simplified stage assemblies comparison cites the saving of 480 man hours – a 50 percent reduction in the man hours required on the five segment motor.

Most impressive is the improved ballistics, with the higher ISP density of the propellent boosting payload performance by nearly 25,000lbm, yet saving $9.2m in costs per booster.

As listed, the increased operating pressure, improved propellant, tailored thrust profile, increased expansion ratio all combine to provide a 15.1mT boost to the SLS’ payload capability.

However, what can’t be estimated is ATK’s foothold as the provider of boosters for NASA’s human space flight program for the past 30 years. A continuation with the familiarity of the solid motors is continually classed as the favored option by SLS sources.

(Images: Via NASA and L2 content from L2′s SLS specific L2 section, which includes, presentations, videos, graphics and internal – interactive with actual SLS engineers – updates on the SLS and HLV, available on no other site.)

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SLS Booster Evolution:

Initially, SLS will launch in the 70mt configuration, ultimately designed to validate the Heavy Lift Launch Vehicle (HLV) for its exploration roles with the Orion spacecraft.

Known as Exploration Mission-1 (EM-1), the SLS will loft Orion for a short uncrewed mission to the Moon.

For this Block 1 configuration, SLS will consist of a core stage using four Pratt and Whitney Rocketdyne (PWD) RS-25Ds – formerly used by the Space Shuttle Program (SSP) – two ATK five segment Solid Rocket Boosters (SRBs) and an Interim Cryogenic Propulsion Stage (ICPS), highly likely to be a Delta Cryogenic Second Stage (DCSS).

The crewed follow-on flight – known as Exploration Mission-2 (EM-2) – is currently scheduled for 2021, while there is also potential for a cargo mission in-between EM-1 and EM-2.

Overall, the exploration roadmap continues to be largely undefined, especially past the opening couple of missions, citing only the vague references of journeys to a Near Earth Asteroid (NEA) and crewed missions to Mars. The potential for an Exploration Gateway to be at the center of NASA’s BEO ambitions continues to be heavily supported within the walls of NASA centers.

Despite the lack of a complete exploration roadmap, the SLS program continues to firm up their plan to evolve the HLV, with the 2020s set to be dominated by the Block 1A or 1B configuration – a 105mt capable launch vehicle that can be used for crew or cargo missions.

One of the main questions surrounding the 105mt capable vehicle relates to the boosters it will utilize for the opening two minutes of its ascent uphill – a choice between ATK’s Solids or an alternative liquid booster. As such, NASA will hold a competition, a trade-off between the suitors.

ATK – with their tried and tested Sold Rocket Motor history with the Shuttle Program – are always cited as being in pole position, per sources, not least because they will be flying with their five segment booster on SLS Block 1 and likely through to first half of the 2020s with the 105mt capable vehicle.

Also, evaluations are being made for baselining the 105mt SLS as the Block 1B, delaying the debut of the advanced boosters until near the end of the 2020s.

The main consideration for staying the course with the Block 1B is from an engineering standpoint, given analysis with the Block 1A – sporting advanced liquid boosters – shows it to be a “high-acceleration” launch vehicle. As such, it has been noted the environments (vibration, loads, etc.) caused by the high acceleration may be higher than Orion will allow.

With this consideration in mind, the SLS teams want to take the Block 1B design to the same level of maturity as the Block 1A, then make a decision on which way to proceed. Source information notes there is enough RSRMV material to conduct 10 SLS missions prior to the need to move to the advanced booster.

ATK are also classed as favorite for remaining as the booster supplier via the outcome of the competition, resulting in two five segment solid-propellant Advanced Composite Boosters (ACBs) being added to SLS. Details are restricted, but sources claim ATK’s Advanced Booster plans have impressed the SLS team.

(Image taken from the amazing 220mb DM-2 Five Seg Motor Ground Test Super Slow engineering Video – available in L2).

However, if a decision is made to switch to liquid boosters, SLS is designed to accommodate them on both the Block 1A and Block 2 – the latter being the fully evolved SLS, capable of at least 130mt to orbit. Attach points and integration considerations mean little impact will be suffered by the HLV, regardless of the future decision into its boosters of choice.

Dynetics Advanced SLS Boosters:

As part of NASA’s SLS Advanced Booster Engineering Demonstration and/or Risk Reduction (ABEDRR) procurement, Dynetics, Inc. and Pratt & Whitney Rocketdyne (PWR) formed a team “to offer an affordable booster approach that meets the evolved capabilities of the SLS” – and presented their overview at the 63rd International Astronautical Congress, Naples, Italy in October.

During the ABEDRR effort, the Dynetics Team will apply state-of-the-art manufacturing and processing techniques to the heritage F-1, resulting in a low recurring cost engine while retaining the benefits of Apollo-era experience. The end goal will be to use NASA test facilities to perform a full-scale F-1 powerpack hotfire for risk reduction engine testing within a 30 month program.

The proposed booster features a robust structural design based around an 18 foot diameter core, paired with two F-1 engines, evolved from the most powerful LOX/RP engines ever flown.

“The Apollo-Saturn F-1 produced by Pratt & Whitney Rocketdyne is still the most powerful U.S. liquid rocket engine ever flown. The F-1 is well suited to the Advanced Booster, providing a combination of high thrust-to-weight and reliability in a low-cost package,” noted the Dynetics presentation, acquired by L2 – LINK.

“PWR brings unique cost and performance lessons from having recently working to modernize another Saturn-era engine, the J-2X.”

Citing their “superior booster solution”, Dynetics note the performance margin inherent to the proposed two-engine F-1-based booster enables a robust approach to structural design. 

The company believes they can reduce costs by using the new Friction Stir Welding machinery at the Marshall Space Flight Center (MSFC) – which was originally intended for the Ares I launch vehicle. As such, AI 2219 material will be used as the basis for the tanks and skirts of the booster.

While the SLS Block 2 – with advanced Solid Rocket Boosters – is estimated to provide a capability of 130mt to orbit, Dynetics claim that by using the vehicle assumptions for the fully evolved SLS, their proposed booster delivers 150mt, “providing a 20mt (15 percent) margin, even with a conservative, affordability-focused booster.”.

Citing the history of the F-1′s flight record, Dynetics also point to the safety of the famous engine, as “demonstrated on 13 Saturn V flights of 65 engines with no failures.”

“The Dynetics Team identified a modernized F-1 engine as the ideal Advanced Booster engine concept because of the Saturn heritage engine 100 percent demonstrated flight reliability; high thrust; and simple, low-pressure LOX/RP GG cycle,” added the presentation.

“As a liquid engine, the F-1 can be acceptance tested to screen for defects prior to integration and, with the vehicle restrained, can be run on the pad for pre-launch readiness demonstration. Finally, if an engine does shut down, the booster can maintain vehicle control by shutting an engine down on the opposite booster, allowing either mission completion or a safe crew escape, depending upon the timing of the shutdown.”

Dynetics also provided their evaluations into initial load estimates, using data from historical booster loads from the Space Shuttle Program (SSP), assumed with the application of conservative factors

“It is believed that this is a conservative assumption (the loads), because many of the load contributors inherent to solid rocket boosters are eliminated or mitigated by liquid engine boosters,” noted their findings. “Examples include thrust rise, thrust rate mismatch at liftoff, thrust oscillation, and thrust and mismatch at separation.”

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The company also referenced the SLS Block 1A, the 105mt capable HLV that – as previously mentioned – is set to be the workhorse of the 2020s.

Most notable is Dynetics’ claim they would be able to achieve 120mt as a non-Block 2 SLS. it is possible this class of HLV would fulfil the requirements of even the most ambitious versions of the NEA missions outlined in the ESD CONOPS (Concept of Operations), and potentially the Mars missions, allowing for the cancellation of the Block 2 to free up money for payloads.

The removal of the Block 2 from the SLS family has been noted as a consideration, albeit “privately” within the SLS program.

“Although the focus of the booster design activity concerned the Block 2 SLS configuration, the performance of the booster concept for the Block 1A SLS configuration (prior to incorporation of the Upper Stage) has also been assessed,” the presentation added.

“For the Block 1A version of the booster, a derated F-1 engine  was baselined  to provide increased reliability by operating at reduced chamber pressure and thrust while building flight heritage for the SLS F-1 in preparation for Block 2. The SLS Block 1A configuration with the proposed Advanced Booster provides payload capability from 103 mT (F-1 derated to 85 percent) to 120 mT (100 percent F-1 power level).”

Dynetics also note that the F-1 driven boosters provide NASA with greater flexibility, based on the projected multi-mission role SLS will be tasked with in the years to come.

“The F-1 engine design has continuous throttling capability over a sea level thrust range of 1.3 to 1.8 Mlbf to provide flexibility that supports SLS program goals  by enabling the ability to tailor the thrust profile for each individual SLS flight and configuration if desired or required,” Dynetics noted.

“SLS is envisioned to fly a diverse range of missions (human, cargo, varying payload mass, varying insertion orbits) using multiple vehicle configurations (Upper Stage, no Upper Stage, varying number of core engines) where the ability to tailor the booster thrust profile provides NASA great flexibility to achieve current and future mission objectives.”

The company is also looking at “commonality and simplification” as Main Propulsion System (MPS) design goals, in order to increase affordability and reliability – leveraging Saturn, Delta IV, and SLS Upper Stage experience to prepare current suppliers to produce large cryogenic components.

“The booster RP feedline is common to the Core engine inlet; coupled with similar or less total propellant, this allows common designs for fill/drain, tank vent and relief, LOX thermal conditioning, and pneumatic system components. (It will) deliver more than 10,000 pounds of propellant each second of operation to a pair of F-1 engines.

“The propellant feed system valves are based on recent engine programs, such as RS-68 and J-2X. An active Pogo suppression system built on Saturn MPS lessons learned has been baselined, and engine feedlines based on S-IC geometries and components have been utilized.

“During flight, the same autogeneous LOX tank and heterogeneous gaseous Helium (GHe) RP tank repressurization systems proven during the Saturn program will be employed.”

While additional options – such as an Ares 1-style “in line” launch vehicle option (see “family” graphic)  - are also presented, the key drive will now take place over the next 30 months, as the Dynetics team work to reduce the risk through a series of full-scale risk mitigation hardware demonstrations under the ABEDRR procurement process.

(Images: L2′s SLS Sections, NASA, ATK and Dynetics/PWR)

(NSF and L2 are providing full exploration roadmap level coverage, available no where else on the internet, from Orion and SLS to ISS and COTS/CRS/CCDEV, to European and Russian vehicles.)

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SLS Design Change:

NASA’s new Heavy Lift Launch Vehicle (HLV) remains on track for its debut on Exploration Mission -1 (EM-1) to the Moon in 2017, after successfully transitioning from the joint System Requirements Review (SRR) and System Definition Review (SDR) to the key PDR stage of development.

While the design of the vehicle – such as the appearance, or Outer Mold Line (OML) – are all-but baselined into what spectators can expect to see roaring off Pad 39B in the second half of this decade, a large amount of fine-tuning is taking place, via the NASA and contractor engineering teams at the Marshall Space Flight Center (MSFC).

The prime contractor is Boeing, who’s involvement with the monster rocket ranges back to prior to the official announcement by NASA, confirming the SLS configuration as a Shuttle Derived (SD) HLV.

As part of the fine-tuning process, Boeing engineers recently recommended a design change relating to the heatshields surrounding the four engines on the core of the SLS. The HLV will initially launch with four Pratt & Whitney Rocketdyne (PWR) RS-25Ds, donated by the Space Shuttle Program (SSP), prior to moving to the non-reusable version, known as the RS-25E.

As seen with the Shuttle orbiters, a dome of Thermal Protection System (TPS) tiles and a ring of white thermal blankets surrounded each of the SSMEs on the aft, with only the Nozzle visible from the outside. This was known as the “eyelid and dome” hardware, something that had remained relatively unchanged during the life of the SSP.

The “eyelid” is the rigid spherical portion attached to the engine nozzle, whereas the “dome” is the portion attached to the orbiter. The dome has a rigid conical portion with TPS tiles on it and a flexible blanket portion with a seal that is pressed against the eyelid with 48 spring cans.

This was a very complex piece of hardware, requiring a lot of refurbishment between flights, one reason it was usually seen undergoing work on the Orbiter Processing Facility (OPF) floor between flights, during the period the SSMEs had been removed from the vehicle.

While one obvious reason for the change could be assumed to the fact SLS core will not be returning home for reuse – at least removing the re-entry considerations – even the orbiter’s engine heat shield design was driven not by the vehicle’s return, but instead by the launch environments.

For previous SLS Articles, click here: http://www.nasaspaceflight.com/tag/hlv/

As such, there are a lot of factors that allow this change to take place. Primarily, it is due to the improvement in flexible thermal protection materials over the 40 years since the orbiter was developed, while the move will also save some weight on the aft of the vehicle.

“The Boeing team is recommending replacement of the heritage orbiter ‘eyelid and dome’ engine heat shields with a flexible blanket similar to what is used for the Solid Rocket Booster nozzles and other expendable launch vehicles,” noted one of the numerous updates on L2′s SLS rolling updates section, confirming the change.

“The blanket design will save approximately 700 pounds in weight while being easier to produce, assemble, and install. The blanket will use the same attachment scheme on the engine nozzle and core base heat shield as the heritage design.”

Click here for Articles specific to the SSME (RS-25s): http://www.nasaspaceflight.com/tag/ssme/

The flexible thermal blankets will be similar to those used around the RS-68 nozzles on the Delta IV, with additional knowledge available from their use on the aft skirt of the Solid Rocket Booster.

As such, engineers will have a database of understanding on how these blankets perform during launch, including any potential challenges – such as that observed during STS-116′s ascent.

Discovery’s launch was nominal. However, long range trackers – used by NASA’s Systems Engineering and Integration (SE&I) group – provided an amazing close up video (available on L2 – LINK) of the two booster nozzles with their blankets vibrating under the intense atmosphere of the exhaust.

The left booster, however, showed its “curtain blanket” was “flapping” during ascent, after becoming partially detached.

It has been noted by sources that the behavior of the blankets is something that will be assessed to make sure the ignition overpressure (IOP) does not cause the blanket to contact the engine powerhead components.

Testing may also be required if the environment at the base of the SLS core is worse than what the existing materials have been certified for. Even if the thermal environment is not worse, the debris or pressure environment may be a relevant area of evaluation.

The design change will debut during the test firings at the NASA Stennis Space Center (SSC). These firings will be known as “Green Run” testing – given they are carried out with the first two flight articles. Since they are the flight articles, using real RS-25 engines, they will have these blankets installed.

(Images: Via L2′s SLS specific L2 section, which includes, presentations, videos, graphics and internal – interactive with actual SLS engineers – updates on the SLS and HLV, available on no other site. Lead image SLS rendering used used with permission from terrabuilder.com and Boeing.)

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The stunning lack of an In-Flight Anomaly Review for STS-135:

For over 30 years, NASA’s Space Shuttle Program relied on the all-powerful and iconic white Solid Rocket Boosters to help propel every single Shuttle mission toward Low Earth Orbit.

For the entire life of Space Shuttle Program, one thing was certain: there would be an In-Flight Anomaly (IFA) review for all Space Shuttle missions to review all vehicle performance indicators and ensure maximum safety for the future.

And that constant held from STS-1/Columbia (April 1981) to STS-134/Endeavour (June 2011). Notably, though, STS-135/Atlantis is missing from the complete list of IFA reviews.

Some people within the program claimed it was related to NASA leaderships’ desire to kill the Shuttle Program as quickly as possible, following the highly successful and triumphant mission of OV-104 Atlantis on STS-135 (8 July – 21 July 2011).

What’s more, the non-performance an IFA review following STS-135 directly contradicted numerous pre-flight reports and statements by Shuttle Program managers, that specifically noted that all post-flight reporting and IFA reviews would follow normal procedures for the last flight of the program.

Essentially, the express desire by Shuttle Program management and NASA itself going into STS-135 was to treat it as if it were just another flight of the Program – as if there would be another flight, which in some sense is true given the large quantity of Shuttle hardware that will still be flown on the Space Launch System (SLS) rocket.

But with the desire to terminate the program as quickly as possible came the 31 August 2011 “official” end to the Shuttle Program – and with it any chance of performing an IFA… something quite baffling when it is considered that numerous Shuttle hardware elements will be used for the Space Launch System rocket (e.g. the SRBs, Space Shuttle Main Engines, External Tank design, Main Propulsion System, etc…).

The directive not to perform an IFA was clearly issued following the successful return of Atlantis from STS-135 as indicated by the Mission Evaluation Room (MER) compilation of an actual IFA list (available for download on L2 – LINK) on 1 August 2011 for review at a later date.

Thus, the appearance of a detailed flight performance and IFA report for any element of STS-135/Atlantis is refreshing – though surprising. 

An inspiringly safe final SRB flight for the Shuttle Program:

Following the launch of STS-135/Atlantis on 8 July 2011, the launch vehicle’s twin SRBs were towed back to the Cape Canaveral for disassembly and post-flight inspection.

This process led to the creation of a detailed flight performance report of Shuttle Atlantis’s Solid Rocket Boosters on 18 August 2011 – not by NASA or Shuttle Program departments but by the contractor agency United Space Alliance (USA).

As noted by the USA Volume II – Solid Rocket Booster presentation for the Space Shuttle STS-135 Flight Evaluation Report (L2 LINK), “All Solid Rocket Booster subsystems performed nominally during launch countdown, flight, and recovery.”

With liftoff of the final Shuttle flight registered at 1129.03 EDT, the launch occurred on the first attempt with “No SRB LCC (Launch Commit Criteria) violations during the time period of SRB power up through launch. No exceedances of the Countdown Experience Base occurred this flight, and all SRB subsystems performed properly during prelaunch testing and launch countdown.”

But perhaps even more impressive than the clean pre-launch performance of the SRBs is the fact that “There were no SRB related In-Flight Anomalies (IFA) on this flight.”

SRB separation loads/events from the launch pad at liftoff:

Designed to bear the entire weight of the fully-fueled Shuttle launch vehicle on the Mobile Launch Platform (MLP), and thus representing the only place to securely bolt the SSV (Space Shuttle Vehicle) to the MLP, each SRB for the Space Shuttle was bolted to the MLP by four hold-down bolts with frangible nuts.

These frangible nuts had to separate prior to liftoff to allow for a clean launch of the SSV from the MLP. Thus, the nuts were designed to separate into two halves via a NASA Standard Detonator – with the fire command being sent to each frangible nut at approximately T-0.3 seconds.

This timing allowed the nuts to separate and fall into their designated receptacles where they were “caught” and prevented from recirculating in the aerodynamic environment around the vehicle induced at SRB ignition – thus preventing the frangible nuts from contacting the launching SSV stack and causing potential damage.

To verify the safety and continued functionality of this system, several post-flight and flight ascent data was collected on each Shuttle mission to verify a clean separation of the SRBs from the MLP and the eight hold-down bolts.

This verification process was performed for STS-135. As noted by the SRB flight performance report, “Post-flight inspection showed that all eight frangible nuts performed nominally, separating into two major halves. All four frangible nut major webs, and both minor webs, were identified in the debris from all eight blast containers.”

Furthermore, there were not stud hang-ups during liftoff, and all hold-down stud loads for STS-135 were well within family for the Space Shuttle Program – indicating a clean separation of the SRBs from the MLP at liftoff.

The maximum hold-down stud load for STS-135 was recorded on Post #2 with a value of 771.5 kips; likewise, the minimum stud load was recorded on Post- #5 just prior to SSME (Space Shuttle Main Engine) start with a value of 609.6 kips.

Both of these values were well within the maximum flight experience base of 841 kips (registered during the December 1988 launch of Atlantis on STS-27) and a historical maximum of 849 kips (registered during the STS-26/Discovery Return to Flight mission’s Flight Readiness Firing of the SSMEs).

Overall SRB ascent performance:

All ascent data points for both SRBs were well within family and consistent with previous nominal flights of the SRBs.

Both RSRM (Reusable Solid Rocket Motor) Ignition PICs (Pyro Initiator Controllers – the hardware that actually ignites the SRB propellant at T-0) met all performance requirements and functioned nominally.

All SRB rate Gyro performances were nominal, and correlated rate data from the Left and Right SRBs and the Orbiter’s rate gyro subsystems were within Shuttle specifications during powered ascent.

Moreover, “All reviewed measurements from the Operational Instrumentation performed properly throughout their respective mission phases for the launch,” notes the SRB performance report.

However, in terms of overall performance, of particular note were the Significant Event Times for STS-135′s SRBs.

While several of the manually initiated commands in the pre-launch timeframe deviated from their predicted time (an expected occurrence), of particular note were four flight event times that deviated ever so slightly from the pre-flight predictions.

The first was the actual time of ignition of the twin SRBs.

Pre-flight expectations showed a 0.006 second delay between the ignition command and the actual ignition of the twin SRBs.

Post-flight analysis of video from the launch pad revealed an actual 0.008 second delay between the ignition command (clocked from the SRB ignite command at T-0) and the actual, simultaneous ignition of the SRBs – a statistically insignificant 0.002 second difference.

Additionally, there was a 0.16 second difference in the time it took both the Left and Right SRBs to drop to a PC less than 50 indication – much better than the pre-flight prediction of a 0.3 second difference.

Likewise, there was a statistically irrelevant 0.2 second different in the safing of the Range Safety System (destruction system) between the two SRBs.

SRB nozzle null commands for SRB separation were nearly identical to each other and to pre-flight predictions; however, physical separation of the SRBs from the External Tank differed from the identical pre-flight prediction of MET (Mission Elapsed Time) 122.97 seconds. 

Physical separation of the Left SRB was registered at MET 123.08 seconds, with the Right SRB’s physical separation recorded at 123.12 seconds.

SRB separation performance:

Nevertheless, all SRB separation commands and performances were classed as nominal during STS-135.

Release of all structural attachments (8 total; 4 on each SRB – 3 on the aft attach bolts to the ET and one on the forward attach bolt to the ET) was completed within 30 milliseconds of the issuance of the separation command from orbiter Atlantis’s General Purpose Computers (GPCs).

Booster Separation Motor (BSM) – thrusters that push the SRBs away and clear from the ET – firing was nominal, with all 16 BSMs firing to completion.

SRB post-separation flight profile:

Both SRBs were tracked by ground-based radar assets from their separation from the ET to their loss of signal (LOS) due to the curvature of the Earth.

This LOS due to the curvature of the Earth nominally occurs at approximately T+340 seconds. But during STS-135, LOS for the Left SRB occurred at T+328 seconds, 12 seconds earlier than normal. Likewise, LOS with the Right SRB occurred at T+308 seconds, a full 32 seconds earlier than normal.

Post-flight review revealed this was due to a problem with the radar tracking site and not the SRBs’ post-separation flight profile.

Additionally, a temporary LOS was registered with the Left SRB at T+202 seconds. The signal was re-acquired at T+239 seconds. This LOS was traced to the same radar tracking site issue that resulted in the early, permanent LOS.

Radar tracking data of SRBs indicated a post-separation apogee altitude (highest altitude achieved) of 223,100 feet for the Left SRB at T+192 seconds and an apogee altitude of 223,200 feet for the Right SRB at T+192 seconds.

This deviated from the pre-flight prediction and Program nominal apogee of 226,836 feet by more than 3,636 feet.

Likewise, peak dynamic pressure on the Left SRB also deviated slightly from historical norms with a registered peak dynamic pressure of 1,500 pounds per square feet (psf) at T+309 seconds v. the historical norm of 1,456 psf at T+313.9 seconds.

Peak dynamic pressure for the Right SRB was not recorded due to the radar track site issue that led to an early LOS.

Nonetheless, both the peak dynamic pressure deviation and shallow apogee of the SRBs were “within the experience base of ascent trajectory planning and post-separation radar tracking.”

Drogue parachute deployments and associated loads were nominal, as was main parachute deployment, inflation, and associated loads.

Horizontal ribbon damage on five of the six main parachutes was reported during post-flight reviews; however, it was not noted during recovery operations if the damage was already present on the parachutes – indicated in-flight damage – or if the damage was caused during recovery operations.

Both SRB extension nozzle jettisons after main chute deploy and before water impact were nominal.

SRB splashdown:

With three fully inflated main parachutes each, both SRBs achieved nominal velocity for splashdown into the Atlantic Ocean.

Deriving splashdown times from “acceleration data recorded by the on-board data acquisition systems,” the Left SRB impacted the water at MET 398.98 seconds. The Right SRB followed with splashdown at MET 403.70 seconds.

Both SRBs hit the water at a relative speed of 76 ft/sec with a horizontal wind velocity measured at 30 ft/sec and seas at 4-6 ft at both splashdown locations.

Information from the Data Acquisition System (DAS) – a system installed in the parachute camera canister in the forward skirt of each SRB to record vehicle acceleration loads from just after liftoff to splashdown in the +/-125 G category – indicated a nominal +11.7 g water impact of both SRBs.

According to the SRB performance report, “This is within the range of normal SRB rigid body axial accelerations experienced for three fully open main parachutes.”

Likewise, post-splashdown cavity collapse occurred 1.17 seconds after splashdown in the Left SRB and 1.10 seconds after splashdown in the Right SRB.

Both cavity collapse times corresponded to in-family parameters from previous flight experience.

Interestingly, accelerometers in both SRBs did not record a “hard SRB splashdown” event that is nominally recorded approximately 3 seconds after water impact.

Thrust Vector Control system performance during flight:

For STS-135, all in-flight performance readings for the critical Thrust Vector Control (TVC) system indicated the proper positioning of all TVC actuators as commanded. 

As noted by the presentation, “During prelaunch and ascent, all actuators positioned as commanded. Actuator rates and duty cycles also correlated with the issued commands.”

All TVC actuator duty cycles correlated well the 134 flight experience base for the Right and Left SRBs, and all rock/tilt numbers fell well within the flight experience envelope.

Nevertheless, there were six minor exceedances in the second-to-second experience base… four for the Left SRB and two for the Right SRB.

The first second-to-second exceedance for the Left SRB occurred at T+12.5 seconds. “The LH Position TVC Tilt Actuator Position B58H1151C exceeded the second-to-second High Experience Base. The experience base high value was 1.89 inches, and the actuator position was 2.71 inches,” notes the USA SRB flight performance report.

This 2.71 inch actuator position was still well within the overall Left SRB maximum flight experience envelope during the roll maneuver.

Likewise, the all the other instances of SRB TVC actuator duty cycles spiking above the second-to-second maximum flight experience base were still contained within the overall maximum flight experience envelope.

SRB Thermal Performance:

Thermal performance reviews for the two SRBs for STS-135 further indicated a very clean and safe flight, with the actual flight thermal environment being “less severe than the current Performance-Enhanced Space Shuttle ascent and 95 percentile descent design environments.”

Click here for recent SRB/RSRM Articles: http://www.nasaspaceflight.com/tag/srb/

No breach to the structural temperature limit exceedances were observed on the recovered SRBs, and all post-flight TPS (Thermal Protection System) conditions were well within family and consistent with previous nominal flights.

SRB in-flight debris environment:

A debris assessment review from ground cameras and on-board flight/engineering cameras from the SRBs and External Tank revealed a nominal performance and no major areas for concern.

In fact, only one squawk, 135-001, was written for “suspect ascent impacts in the RH ETA (External Tank Attach) Ring froth-pak foam,” notes the SRB performance report.

Post-flight analysis of the impact area revealed no foreign debris, and the impact areas themselves were consistent with previously-observed ice impacts to ETA ring froth-pak foam.

Moreover, all observed post-flight material loss was within flight experience and easily attributed to post-separation, splashdown, and recovery activities.

SRB onboard camera performance:

All four SRB engineer cameras and four Solid State Video Recorders (two per SRB) functioned nominally during first stage flight.

Likewise, ET-facing engineering cameras on the SRBs to monitor engineering targets of interest during SRB separation from the ET functioned as expected and collected good engineering images of the ET intertank panel during separation.

The camera feeds from the ET-facing cameras automatically switched to the parachute cameras 5mins 50seconds after liftoff. Nominal observation of the parachute deployment sequence was observed on both SRBs by the parachute engineering cameras (one per SRB).

An excellent final performance of exceptional hardware/propulsion element:

Overall, STS-135 appears to be the cleanest and safest flight of the ATK-produced Solid Rocket Boosters in the history of the Shuttle Program with ZERO In-Flight Anomalies indicated during preliminary post-flight inspections and only ONE squawk for damage that most likely was caused from ice from the External Tank, not the SRBs.

However, it is impossible to verify if this was, as suspected and indicated, the cleanest and most-successful flight of the Solid Rocket Boosters as no formal IFA review was held.

Nonetheless, the SRBs ended their service to the Shuttle Program as tried, true, and safe propulsive elements – thanks in great part to NASA’s and ATK’s intense desire to safely use the SRBs.

Obviously, this level of safe use changed significantly in 1986, finally morphing into what it always should have been.  But throughout the life of the Shuttle Program, continuous efforts were taken – at a different level of enthusiasm in the early days of the Program – to learn about and improve upon the SRB design.

This strategy and desire was greatly aided by the fact that 133 of the 135 SRB flight sets were recovered after launch, disassembled and painstakingly scrutinized for any defects or off-nominal indications.

Only two flight sets (4 SRBs total) throughout the life of the Program were not recovered: those on STS-51L/Challenger and those on STS-4/Columbia. The SRBs on STS-4/Columbia suffered parachute deployment failures and impacted the Atlantic Ocean at terminal velocity, shattering into multiple pieces and sinking to the bottom of the Atlantic.

Through this recovery and post-flight inspection process, safety levels continuous improved – even reaching the point of suspending Shuttle flight operations in the mid-1990s to address a partial burn-through of an inner O-ring on just one SRB.

And NASA’s use of SRBs is not over.  SRBs will continue to serve manned and unmanned launch endeavors for NASA as the Shuttle’s successor vehicle, the SLS rocket, makes use of twin 5-segment SRBs, verse the Shuttle’s 4-segment Solids, for its debut series of flights currently anticipated for the latter years of this decade.

To read about the orbiters -  from birth, processing, every single mission, through to retirement, click here for the links:
http://forum.nasaspaceflight.com/index.php?topic=25837.0

(Images: L2′s STS-135, SRB, RSRM and IFA sections – all highly expansive collections of presentations, photos, video and data. Additional via NASA and Brian Papke - MaxQ Entertainment/NASASpaceFlight.com.)

(L2 and NSF are continuing to follow the orbiters through to their final resting places. To join L2, click here: http://www.nasaspaceflight.com/l2/)

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Fighting For Liberty:

Although Liberty is less known than the Falcon 9/Dragon combination – a duo that have already launched into space – ATK are pushing forward at a pace to bring their commercial crew transportation system into the running for returning the US’ domestic launch capability, lost after the retirement of the Space Shuttle fleet.

Currently working with NASA via an unfunded Space Act Agreement (SAA) – as opposed to being funded by the Commercial Crew Development (CCDev) process – the pressure is firmly on the shoulders of all the suitors interested in transporting Americans to Low Earth Orbit (LEO) to produce an attractive package of hardware and schedules, pressure that has been increased, due to some political wishes to downselect to a single NASA partner.

When the Liberty launch vehicle was announced, it was noted the rocket would be capable of launching most of the spacecraft put forward for commercial LEO operations. However, it lacked a commitment from one of the other commercial companies, unlike the United Launch Alliance’s (ULA) Atlas V, a vehicle that has since been confirmed as the rocket of choice for SNC’s Dream Chaser, Boeing’s CST-100 and initially Blue Origin’s spacecraft.

Now the game has changed again, with ATK announcing it has found a spacecraft to pair up with Liberty, a capsule that is literally part of what is now a complete transportation system. That capsule is their own spacecraft, thus the entire stack will be known as Liberty.

This complete system, including the spacecraft, launch abort system, launch vehicle, and ground and mission operations, is being designed from inception to meet NASA’s human-rating requirements.

Liberty will hit the ground running, with the schedule showing the first of potentially several test flights will begin in 2014, launching from the Kennedy Space Center (KSC) with L2 information (L2 Link) claiming the test flights will take place from Pad 39B on a modified Mobile Launch Platform (MLP). As such, the test version of Liberty will be the first vehicle to launch from KSC since Atlantis rode uphill on STS-135.

The full scale Liberty is currently designed to launch off the former Ares I Mobile Launcher (ML). However, that has since been repurposed for use with the Space Launch System (SLS), meaning Liberty will either require an additional ML or a redesigned MLP from the former Space Shuttle Program (SSP).

In 2015, Liberty is scheduled to make its debut crew flight, a schedule ATK claim will support crewed missions for NASA and other potential customers by 2016, with a price-per-seat that is projected to be lower than the cost on the Russian Soyuz rocket.

Liberty – First Stage:

KSC will be no stranger to the first stage of the Liberty launch vehicle, given it utilizes a Solid Rocket Booster (or Motor in this scenario), a key element of Shuttle heritage, bar its additional muscle of being a five segment, as opposed to a four segment, motor.

(Image taken from the amazing 220mb super slow-mo DM-3 Five Seg Motor Ground Test Video – available in L2 – LINK).

With the appearance of an Ares I – given it works on the same aerodynamic design principle – the first stage is the same design that was tested during the DM-3 test in Utah, and is the same motor that will initially provide the bulk of the lift-off power for the SLS, with two five segment boosters set to debut with the Heavy Lift Launch Vehicle (HLV) in 2017.

“Our goal in providing Liberty is to build the safest and most robust system that provides the shortest time to operation using tested and proven human-rated components,” said Kent Rominger, vice president and program manager for Liberty.

“Liberty will give the U.S. a new launch capability with a robust business case and a schedule that we expect will have us flying crews in just three years, ending our dependence on Russia.

“Liberty will enable a successful commercial space program and result in a globally competitive capability that America doesn’t have today. This program is changing the way we do business and can also result in a positive change to government programs.”

During the Constellation Program, the five segment motor was observed as suffering from the phenomenon of Thrust Oscillation (TO) during the Ares I development process – requiring additional hardware to “dampen” the effects on the crew riding atop of the vehicle.

However, the DM ground tests – and their vast array of instrumentation, aimed at gathering more detailed data on RSRM (Reusable Solid Rocket Motor) behaviour during the first stage of launch, on the final shuttle missions – have proven TO to be less than expected.

Notably, the Liberty Upper Stage is also a different design when compared to the Ares I Upper Stage, further decoupling the potential TO effects, especially as TO was heavily related to the Ares I stack in the configuration with the Orion crew vehicle.

Liberty – Upper Stage:

Liberty’s Upper Stage is the Core Stage (EPC) of the Ariane 5 launch vehicle used by Arianespace, which will be supplied under contract with EADS/Astrium North America.

The latest generation of the Ariane 5 is based on an evolution of the Vulcain engine that powers the cryogenic core stage. This evolution, called Vulcain 2, provides an increased thrust through an overall mixture ratio and liquid oxygen mass flow increase.

The EPC stage is 5.4 m in diameter and 31 m long on the Ariane 5. It is powered by one Vulcain 2 engine that burns liquid hydrogen (LH2) and liquid oxygen (LO2) stored in two tanks separated with a common bulkhead. The LO2 tank is pressurized by gaseous helium and the LH2 one by a part of gaseous hydrogen coming from the regenerative circuit.

The Vulcain 2 engine develops 1390 kN maximum thrust in vacuum. Its nozzle is gimballed for pitch and yaw control.

The engine is turbopump-fed and regeneratively cooled. The thrust chamber is fed by two independent turbopumps using a single gas generator. A cluster of GH2 thrusters are used for roll control. The engine utilizes two turbo-pumps, driven by a gas generator, and sports a GHe pressurization system for the LOX tank and GH2 for LH2 tank.

Ignition of the engine is obtained by pyrotechnic igniters and occurs nine seconds before lift-off in order to check that’s it’s functioning properly. It is understood that this core stage on the Liberty Upper Stage can be air-started, as would be required during its role with Liberty.

“Astrium is proud to be part of the ATK Liberty team and to provide our proven  second stage, which is powered by the Vulcain 2 engine, as an integral part of this exciting next-generation launch system,” said John Schumacher, CEO of Astrium in North America, an EADS North America company.

“Initially, we will ship the second stage to the Kennedy Space Center where it will be integrated by the skilled workforce there. However, once Liberty’s business base is established in the U.S. market, we envisage Liberty upper stage manufacturing in the United States.”

The configuration of a solid first stage and liquid second stage lowers the likelihood of failure, claimed ATK, and enables a flight path with total abort coverage, maximizing survival for the crew in the unlikely event of an anomaly requiring an abort.

Liberty’s performance of 44,500 pounds to LEO enables the system to launch both crew and cargo and also serve non-crewed markets including ISS cargo up and down mass, commercial space station servicing, US government satellite launch, and future endeavors.

Liberty – Crew Capsule:

In announcing the Liberty spacecraft confirmation as part of the final design package, ATK claim their design leverages design work performed at NASA Langley Research Center (LaRC) on the composite crew module and launch abort system, for which ATK was a contractor, and also the service module design work performed by NASA Glenn Research Center.

Although its birth fell under the radar, ATK provided details on this spacecraft back in 2009, as the company delivered a full-scale, crew module structure made of composite materials to NASA for structural testing.

The Composite Crew Module (CCM) is a unique capsule design that has the potential to reduce the overall weight of future manned launch vehicles, a unique design in that it was specifically built to resemble a space capsule.  

Full-scale structural testing was performed at NASA LaRC to determine the strength and viability of the composite structure. During the destructive testing, the CCM was placed under load conditions similar to those observed during launch, on-orbit, landing, and abort scenarios.

Led by the NASA Engineering and Safety Center (NESC), ATK was part of a team of NASA and industry experts who designed and fabricated the CCM to demonstrate how composite materials could be used to develop a pressurized space capsule.

Constructed in two primary sections, the upper and lower shells are joined together with a splice joint and cured using out-of-autoclave technology.  The bonding of the composite assemblies and integration of metal hardware were achieved by combining existing technology and ATK’s innovative manufacturing processes.

“We believe that no other offering can match Liberty’s safety, spacious spacecraft, customer service and performance,” Mr Rominger added. “These traits enable the Liberty business to provide the best commercial space flight experience.”

Liberty – MLAS:

Although only referenced by name in ATK’s release on the Liberty announcement, the Max Abort Launch System – or MLAS (named after Maxime (Max) Faget) – is another element from the cancelled Constellation Program.

Although it was never publicly admitted, this system was often mentioned by sources as a potential solution towards a growing movement associated with cancelling Ares I and human rating the Ares V, as the Constellation Program began to falter.

It also had the backing of then-NASA administrator Mike Griffin, which would not have come as a surprise, given MLAS was an evolution of two of the original three LAS concepts studied by Constellation, one of which made the LAS trade study in 2007 via a rather amusing hand-drawn sketch, created in 2006.

The MLAS concept combines the boost protection cover of the service module mounted escape system with the command module mounted motors, in turn reducing the overall height of the vehicle – something desired by the Ares V HR advocates, who were worried about being able to stack and rollout the vehicle – with a LAS tower – under the height restrictions of the Vehicle Assembly Building (VAB) doors.

The MLAS utilizes a ‘bullet’ boost protection cover over the capsule to house four Mk 70 Terrier solid motors separation motors – as opposed to locating them on a tower above the capsule.

Two orientation parachutes are attached to the top of the fairing to re-orient the vehicle, with the blunt heat shield to aid in fairing separation.

The design resulted in the aborting vehicle re-orienting immediately after abort motor cut off during a pad abort, but would fly with its nose “into the wind” on a mid-altitude abort. The orientation parachutes would then activate quickly before the fairing separation.

In the event of a high altitude abort, the fairing would come off immediately, in order to allow the Command Module Reaction Control System (RCS) to stabilize the vehicle for entry.

The design of MLAS changed several times during its development, gaining fins for stability during later cycles, becoming more in line with another hand drawn sketch.

This time the artist was former Constellation head Scott “Doc” Horowitz – as seen in the second of two MLAS presentations acquired by L2 (Link to Presentations) – over a year after Mr Griffin’s conceptual design.

The final version of the MLAS flight test vehicle weighed in at over 45,000 lbs and was over 33 feet tall – and this vehicle actually got to fly for real, after being shipped to Wallops for its one and only hop off the ground.

The pad abort test proper began seven seconds after burnout of some specially attached solid motors, as the vehicle rose into the Virginia morning sky at 6:25am local time on July 8, 2009.

Video of the launch showed a perfect test, as the vehicle rose on a stable flight path, before reorientation and further stabilization, followed by crew module simulator separation from the MLAS fairing, and parachute recovery of the crew module simulator.

Other tests were planned for MLAS, including a high altitude abort = which will involve the fairing being released immediately after abort is called, in order to allow the Command Module Reaction Control System (RCS) to stabilize the vehicle for entry. However, the program was put on the backburner, as the Constellation Program found itself cancelled.

It is not yet known if the Liberty program will carry out further MLAS tests, given NASA’s exploration effort relating to the system is now over – with the Space Launch System (SLS) that will launch Orion set to use the previously chosen Line Tandem Tractor (Tower) design as its LAS.

Liberty – Jobs:

Liberty’s announcement also noted its industry base, a key selling point in this post-Shuttle era where thousands of skilled engineers lost their jobs. As such, the ATK release claimed the Liberty system would sustain thousands of jobs across the United States including Alabama, California, Colorado, Florida, Maryland, New York, Ohio, Texas, Utah, and Virginia.

Citing the system’s “low remaining development cost” will accelerate the time to market, in turn meeting NASA’s requirements, the system will provide a quicker return on investment to outside entities

One of the major players in Liberty – Lockheed Martin – is providing crew interface systems design, subsystem selection, assembly, integration and mission operations support for the Liberty spacecraft. These subsystems could include avionics, guidance navigation and control, propulsion systems, environmental control system, docking system and other components.

“Combining Lockheed Martin’s and ATK’s decades of human spaceflight experience to create the Liberty space vehicle will help ensure America’s crew access to the International Space Station – sooner rather than later,” said Scott Norris, Lockheed Martin Lead, Liberty Program.

“We look forward to our role supporting Liberty as it delivers on a highly-effective cost solution for NASA crew and for commercial missions.”

Continuing to work under the ongoing SAA, as part – albeit unfunded – of the CCDev-2 program, the team has successfully completed four milestones. The next major milestone is a structural test of the second stage tank, to be conducted at Astrium in June.

“Working with the NASA team under the SAA has provided significant benefit to the development of the Liberty crew transportation system,” added Mr Rominger.

The Liberty team will be working with NASA centers to further leverage lessons learned, engineering expertise test, launch facilities and mission operations, including Kennedy, Johnson, Marshall, Langley, Glenn, Ames and Stennis.

Additional subcontractors for Liberty include Safran/Snecma, which provides the Vulcain 2 engine; Safran/Labinal, which provides second stage wiring; L-3 Communications Cincinnati Electronics, which provides first stage, abort and telemetry system avionics, as well as second stage telemetry and abort system integration prior to launch at KSC; and Moog Inc, which provides thrust vector control and propulsion control.

(Images: Via L2, NASA, Arianespace and ATK)  (NSF and L2 are providing full transition level coverage, available no where else on the internet, from Orion and SLS to ISS and COTS/CRS/CCDEV, to European and Russian vehicles. 

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