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For this Block 1 configuration, SLS will consist of a core stage using four Pratt and Whitney Rocketdyne (PWD) RS-25Ds \u2013 formerly used by the Space Shuttle Program (SSP) \u2013 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).<\/p>\n
The crewed follow-on flight \u2013 known as Exploration Mission-2 (EM-2) \u2013 is currently scheduled for 2021, while there is also potential for a cargo mission in-between EM-1 and EM-2.<\/p>\n
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\u2019s BEO ambitions continues to be heavily supported within the walls of NASA centers.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/11\/Z417.jpg\" "\\"Z417\\"")
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 \u2013 a 105mt capable launch vehicle that can be used for crew or cargo missions.<\/p>\nSpaceflight
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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 \u2013 a choice between ATK\u2019s Solids or an alternative liquid booster. As such, NASA will hold a competition, a trade-off between the suitors.<\/p>\n
ATK \u2013 with their tried and tested Sold Rocket Motor history with the Shuttle Program \u2013 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.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/11\/Z515.jpg\" "\\"Z515\\"")
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.<\/p>\nThe main consideration for staying the course with the Block 1B is from an engineering standpoint, given analysis with the Block 1A \u2013 sporting advanced liquid boosters \u2013 shows it to be a \u201chigh-acceleration\u201d 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.<\/p>\n
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.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/11\/A3171.jpg\" "\\"A3171\\"")
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\u2019s Advanced Booster plans have impressed the SLS team.<\/p>\n(Image taken from the amazing 220mb DM-2 Five Seg Motor Ground Test Super Slow engineering Video \u2013 available in L2).<\/p>\n
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 \u2013 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.<\/p>\n
Dynetics Advanced SLS Boosters:<\/p>\n
As part of NASA\u2019s SLS Advanced Booster Engineering Demonstration and\/or Risk Reduction (ABEDRR) procurement, Dynetics, Inc. and Pratt & Whitney Rocketdyne (PWR) formed a team \u201cto offer an affordable booster approach that meets the evolved capabilities of the SLS\u201d \u2013 and presented their overview at the 63rd International Astronautical Congress, Naples, Italy in October.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/11\/Z91.jpg\" "\\"Z9\\"")
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.<\/p>\nThe 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.<\/p>\n
\u201cThe 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,\u201d noted the Dynetics presentation, acquired by L2 \u2013 LINK.<\/p>\n
\u201cPWR brings unique cost and performance lessons from having recently working to modernize another Saturn-era engine, the J-2X.\u201d<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/11\/Z74.jpg\" "\\"Z7\\"")
Citing their \u201csuperior booster solution\u201d, Dynetics note the performance margin inherent to the proposed two-engine F-1-based booster enables a robust approach to structural design. <\/p>\nThe company believes they can reduce costs by using the new Friction Stir Welding machinery at the Marshall Space Flight Center (MSFC) \u2013 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.<\/p>\n
While the SLS Block 2 \u2013 with advanced Solid Rocket Boosters \u2013 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, \u201cproviding a 20mt (15 percent) margin, even with a conservative, affordability-focused booster.\u201d.<\/p>\n
Citing the history of the F-1\u2019s flight record, Dynetics also point to the safety of the famous engine, as \u201cdemonstrated on 13 Saturn V flights of 65 engines with no failures.\u201d<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/11\/Z54.jpg\" "\\"Z5\\"")
\u201cThe 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,\u201d added the presentation.<\/p>\n\u201cAs 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.\u201d<\/p>\n
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<\/p>\n
\u201cIt 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,\u201d noted their findings. \u201cExamples include thrust rise, thrust rate mismatch at liftoff, thrust oscillation, and thrust and mismatch at separation.\u201d<\/p>\n
For previous SLS Articles, click here: http:\/\/www.nasaspaceflight.com\/tag\/hlv\/<\/p>\n
The company also referenced the SLS Block 1A, the 105mt capable HLV that \u2013 as previously mentioned \u2013 is set to be the workhorse of the 2020s.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/11\/Z81.jpg\" "\\"Z8\\"")
Most notable is Dynetics\u2019 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.<\/p>\nThe removal of the Block 2 from the SLS family has been noted as a consideration, albeit \u201cprivately\u201d within the SLS program.<\/p>\n
\u201cAlthough 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,\u201d the presentation added.<\/p>\n
\u201cFor 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).\u201d<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/11\/Z102.jpg\" "\\"Z10\\"")
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.<\/p>\n\u201cThe 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,\u201d Dynetics noted.<\/p>\n
\u201cSLS 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.\u201d<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/11\/Z64.jpg\" "\\"Z6\\"")
The company is also looking at \u201ccommonality and simplification\u201d as Main Propulsion System (MPS) design goals, in order to increase affordability and reliability \u2013 leveraging Saturn, Delta IV, and SLS Upper Stage experience to prepare current suppliers to produce large cryogenic components.<\/p>\n\u201cThe 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.<\/p>\n
\u201cThe 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.<\/p>\n
\u201cDuring flight, the same autogeneous LOX tank and heterogeneous gaseous Helium (GHe) RP tank repressurization systems proven during the Saturn program will be employed.\u201d<\/p>\n
While additional options \u2013 such as an Ares 1-style \u201cin line\u201d launch vehicle option (see \u201cfamily\u201d graphic) \u2013 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.<\/p>\n
(Images: L2\u2019s SLS Sections, NASA, ATK and Dynetics\/PWR)<\/p>\n
(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.)<\/p>\n
(Click here to join L2: http:\/\/www.nasaspaceflight.com\/l2\/ )<\/p>\n","protected":false},"excerpt":{"rendered":"
One of the most famous rocket engines in history \u2013 the Apollo\/Saturn\u2019s F-1 \u2013 could one day fly again, providing Alabama company Dynetics, teamed with Pratt and Whitney Rocketdyne (PWR), win the advanced booster competition for the Space Launch System (SLS). Their liquid booster approach would advance SLS\u2019 capability to launch payloads of 150mt to […]<\/p>\n","protected":false},"author":1,"featured_media":30434,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[8897,9034,624,7806],"class_list":["post-39979","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-boosters","tag-hlv","tag-sls","tag-srb"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/39979"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=39979"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/39979\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/30434"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=39979"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=39979"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=39979"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}