![\"SLS](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2013\/01\/Z4.jpg\" "\\"SLS")
While Ares I had managed to get through the PDR stage prior to its demise, major SLS elements \u2013 such as the Core Stage \u2013 are already fast approaching the point of maturity Ares I\u2019s Upper Stage had achieved.<\/p>\nNASA\u2019s Space Launch System (SLS) is deep into preparations for the key milestone of the Preliminary Design Review (PDR), which \u201ckicks off\u201d in June. Meanwhile, an interesting glimpse into the long-term plan for SLS points towards the favored use of a dual-use Upper Stage \u2013 powered by up to four RL-10 engines \u2013 known as the \u201cDuce\u201d.<\/p>\n<\/p>\n
SLS Progress:<\/p>\n
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).<\/p>\n
While Ares I had managed to get through the PDR stage prior to its demise, major SLS elements \u2013 such as the Core Stage \u2013 are already fast approaching the point of maturity Ares I\u2019s Upper Stage had achieved.<\/p>\n
As such \u2013 and despite a compressed schedule to make its debut launch target in 2017 \u2013 SLS is on track and continues to enjoy several months of schedule margin.<\/p>\n
Of course, as with any rocket, SLS\u2019 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.<\/p>\n
As noted in L2\u2019s SLS Development Update Section, engineers are also looking at the design of the booster nose cones, due to an aeroacoustic loading issue \u2013 in the transonic flight region \u2013 impacting on the booster\/core attach points, per evaluations.<\/p>\n
NASA educational resources (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n Notably, per all recent information, none of SLS\u2019 challenges have resulted in a major concern on its report cards, unlike Ares I\u2019s troublesome childhood.<\/p>\n 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 \u2013 the Critical Design Review (CDR) in 2015.<\/p>\n The depth of the PDR can be seen via one status update that noted one department\u2019s \u201cdata pack\u201d consisted of over 300 documents \u2013 200 of which were created for the Interim Cryogenic Propulsion Stage (ICPS) by Boeing\/United Launch Alliance (ULA) \u2013 before being sent for review at five NASA centers.<\/p>\n Per L2 information, the review of that PDR data pack \u2013 for the Spacecraft and Payload Integration Office (SPIO) \u2013 is now complete, with the reviewers adding what are known as candidate Review Item Discrepancies (RIDs).<\/p>\n Following the Board meeting, document developers will begin the process of implementing the RIDs in the documents.<\/p>\n 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.<\/p>\n The formal \u201ckick off\u201d for the SLS PDR is on track for June 18-19.<\/p>\n For previous SLS Articles, click here: http:\/\/www.nasaspaceflight.com\/tag\/hlv\/<\/p>\n 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) \u2013 the latter ensuring all open items from DCR are closed out prior to flight.<\/p>\n Evolved SLS via the PDR:<\/p>\n Per L2 information, one of the documents in the SLS PDR data pack is the \u201cEvolvability Report\u201d, which is a technical evaluation for potential development paths by which the Block 1 SLS can be \u201cevolved\u201d to its full capability, as required by Congress.<\/p>\n 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.<\/p>\n The final evolution will be to the Block 2 SLS, which is classed as the flagship launch vehicle for crewed missions to Mars.<\/p>\n While the Evolvability Report is nothing more than a technical evaluation for decision makers \u2013 and does not represent any actual decisions by NASA for future SLS development \u2013 it does provide an interesting insight into SLS\u2019 growth options.<\/p>\n 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).<\/p>\n Option 3 takes SLS along a different path, with the development of a Dual-Use Upper Stage (DUUS \u2013 pronounced \u201cDuce\u201d), followed by development of the Advanced Boosters.<\/p>\n Per L2 information, each of the options were evaluated for their \u201cmission capture\u201d 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 \u2013 such as the increase in payload capability when the Advanced Boosters debut with the HLV.<\/p>\n 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 \u201cmission capture\u201d results, followed by Option 2.<\/p>\n 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.<\/p>\n Then, after Orion separates, it would conduct a disposal maneuver to crash the stage into the Moon.<\/p>\n 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 \u2013 the latter with diameters of 5.0, 5.5, and 6.3 meters, respectively.<\/p>\n 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).<\/p>\n 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 \u2013 in addition to the high efficiency engines \u2013 this should equate to less stage dry mass, resulting in additional payload up-mass capability.<\/p>\n The information also shows the SLS Block 2 \u2013 again with the 8.4 meter diameter 4xRL-10 stage \u2013 with Advanced Boosters, allowing for an up-mass capability of 155mT to LEO and 61mT to BEO.<\/p>\n While the forward path for evaluating all of the options will result in no immediate decisions, the \u201cDuce\u201d is already being cited as a large money-saver, not least because it would likely allow SLS to remain with its four RS-25E\u2019s on the core stage, removing the redesign requirements to move to a five engine core when SLS evolves.<\/p>\n Further articles will follow during the PDR process.<\/p>\n (Images: Via L2 content from L2\u2019s SLS specific L2 section, which includes, presentations, videos, graphics and internal \u2013 interactive with actual SLS engineers \u2013 updates on the SLS and HLV, available on no other site. Other images via NASA and ULA)<\/p>\n (L2 is \u2013 as it has been for the past several years \u2013 providing full exclusive SLS and Exploration Planning coverage. To join L2, click here: http:\/\/www.nasaspaceflight.com\/l2\/)<\/p>\n","protected":false},"excerpt":{"rendered":" NASA\u2019s Space Launch System (SLS) is deep into preparations for the key milestone of the Preliminary Design Review (PDR), which \u201ckicks off\u201d in June. Meanwhile, an interesting glimpse into the long-term plan for SLS points towards the favored use of a dual-use Upper Stage \u2013 powered by up to four RL-10 engines \u2013 known as […]<\/p>\n","protected":false},"author":1,"featured_media":30405,"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":[9112,9034,2222,624,7806,8116],"class_list":["post-39839","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-cps","tag-hlv","tag-icps","tag-sls","tag-srb","tag-ssme"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/39839"}],"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=39839"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/39839\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/30405"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=39839"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=39839"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=39839"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Nose](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2013\/05\/Z452.jpg\" "\\"Nose")
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\u2019s Advanced Boosters, in order to mitigate the issue.<\/p>\nSee Also<\/h4>\n
\n
![\"SLS](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2013\/06\/Z8.jpg\" "\\"SLS")
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.<\/p>\n![\"SLS](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2013\/06\/Z417.jpg\" "\\"SLS")
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.<\/p>\n![\"SLS](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2013\/05\/Z911.jpg\" "\\"SLS")
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.<\/p>\n![\"RL-10](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2013\/06\/Z87.jpg\" "\\"RL-10")
Expanding on the DUUS option, this stage \u2013 driven by up to four RL-10 engines \u2013 would be tasked with completing the ascent phase of the SLS after Core Stage burnout, before then operating as an In-Space Stage \u2013 hence, the \u201cdual use\u201d tag \u2013 to conduct the Trans-Lunar Injection (TLI) burn for an Orion spacecraft, coast to the Moon and conduct the Lunar Orbit Injection (LOI) burn.<\/p>\n![\"SLS](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2013\/06\/B9.jpg\" "\\"SLS")
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.<\/p>\n![\"Duce](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2013\/05\/Z420.jpg\" "\\"Duce")
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).<\/p>\n