- \n
- SLS Forum Section<\/li>\n
- L2 SLS Section<\/li>\n
- Click here to Join L2<\/li>\n<\/ul>\n
Based on development and funding cycles, such exploration is targeted for the 2020s, ahead of the ultimate goal of launching crewed missions to Mars in the 2030s.<\/p>\n
However, the vehicle was provided with an initial launch target of 2017, based on political language in the 2010 Authorization Act.<\/p>\n
Such a target would have seen the rocket launched on an uncrewed test flight, prior to then standing down for another four years ahead of a crewed repeat of the first mission.<\/p>\n
![\"2015-06-30-123904\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2015\/06\/2015-06-30-123904-350x238.jpg\")
The reason for such an advanced launch date was largely related to the caveat of Orion providing a \u201cback up\u201d role to the Commercial Crew Program (CCP) \u2013 in the event of a serious setback for (both of) the commercial providers.<\/p>\nSuch a requirement was never taken too seriously by NASA, not least because such a scenario would involve the overpowered 70mT capable Block 1 SLS (as such launching with \u201ctons of ballast\u201d) lofting a Beyond Earth Orbit (BEO) designed Orion (to LEO), with a crew on its debut mission (safety rules call for a uncrewed debut), at a cost that would probably solve any of the Commercial Crew Program woes that initiated such a backup requirement.<\/p>\n
While the opening mission for SLS has since slipped to 2018 \u2013 and the mission plans are now evolving \u2013 some of the fallout from the political language remains, specifically involving the \u201cinterim\u201d Upper Stage.<\/p>\n
Astronomy
<\/path>Spaceflight history books <\/path>Technology News <\/path>\n (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2013\/05\/Z317.jpg\")
The Block 1 SLS is the \u201cbasic model\u201d, sporting a Delta Cryogenic Second Stage (DCSS), renamed the Interim Cryogenic Propulsion System (ICPS) for SLS.<\/p>\nThe current plan calls for this stage to be used on Exploration Mission -1 (EM-1) and Exploration Mission -2 (EM-2), prior to moving to the EUS \u2013 also to be built by Boeing \u2013 that will become the workhorse for SLS.<\/p>\n
However, using the ICPS on a crewed mission will require it to be human rated. It is likely NASA will also need to fly the EUS on an unmanned mission to validate the new stage ahead of human missions.<\/p>\n
This has been presenting NASA with a headache for some time, although it took the recent ASAP meeting to finally confirm those concerns to the public.<\/p>\n
![\"2015-06-30-132507\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2015\/06\/2015-06-30-132507-350x247.jpg\")
\u201cThe next big event is test flight Exploration Mission (EM)-1, on track for 2018 \u2013 a 24-day, uncrewed
\ncis-lunar voyage that will inject a lot of energy into the Program. The following flight, EM-2 that will have a crew, brings up an issue that deserves attention,\u201d noted the minutes from the meeting.<\/p>\n\u201cPresently, the Program does not have the upper stage that it needs because of lack of funding. A new upper stage, called the Exploration Upper Stage (EUS), will be developed for future crewed flights.<\/p>\n
\u201cAs a fall back, NASA is planning to use the Interim Cryogenic Propulsion System (ICPS) that will get the job done through the test flight, but it is not what NASA will be using eventually.\u201d<\/p>\n
*Click here for more SLS News Articles*<\/p>\n
The ASAP was told it will cost \u201cat least $150 million\u201d to human-rate the ICPS, something the panel believe \u201cwill be wasted because this design will be \u2018tossed\u2019 in the near future.\u201d<\/p>\n
UPDATE: References to the \u201cengine\u201d were cited at the meeting, but NASA later clarified the cost is associated with the entire ICPS.<\/p>\n
![\"2015-06-30-132743\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2015\/06\/2015-06-30-132743-350x255.jpg\")
While the panel noted it understands NASA is at the mercy of political funding constraints, the ASAP informed the NASA managers present to have a \u201cgo\/no-go\u201d decision by this fall on which way to proceed, adding they wish to \u201cencouraged those that control the funds to think about the best use of that $150 M \u2013 should it be applied to the new stage (the EUS) or the old?\u201d<\/p>\nThe DCSS for EM-1 is already into the process of \u201ccutting metal\u201d and will be into full production by the time that decision point is met.<\/p>\n
While EM-1 is all-but certain to be flying with the DCSS during the test flight, the question of when to switch to the EUS is fast becoming a major focal point.<\/p>\n
![\"2015-06-30-132842\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2015\/06\/2015-06-30-132842-350x247.jpg\")
Advancing the EUS to be ready for the start of crewed mission would remove a large concern, per comments made to the panel by Bill Hill, Associate Administrator for Exploration Systems Development (ESD).<\/p>\nSpeaking of his \u201cworry list\u201d, the ICPS was classed as being at the very top. The concerns include completing the hazard analysis on time and the issue of a delay to some of the human-rating evaluations until later in the development cycle.<\/p>\n
\u201cThis is a conservative use of money, but this delays the hazard analysis that normally is done as part of the design. When hazard analysis are done late, they simply document the design instead of informing it. This is a classic mistake in the system safety world,\u201d added the minutes.<\/p>\n
![\"2015-06-30-132927\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2015\/06\/2015-06-30-132927-350x245.jpg\")
This could also be a smart move on NASA\u2019s part, given almost everyone within the SLS Program is eager to move to the EUS as soon as possible, not least because it opens up the mission capabilities for the Heavy Lift Launch Vehicle \u2013 with the current lack of missions a major public concern.<\/p>\nThere is also now political language to help facilitate the switch, laying the foundations to support a key decision point that calls for an advancement of the EUS plans.<\/p>\n
\u201cThe Committee is concerned that NASA will attempt to take the Interim Cryogenic Propulsion Stage (ICPS) that will be used for EM\u20131 and create a human-rated variant. In doing so, NASA would spend $150,000,000 to develop a human-rated stage that would be used only once, before being replaced by the Exploration Upper Stage (EUS),\u201d noted a Senate appropriations committee report.<\/p>\n
![\"Z8\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2014\/02\/Z86.jpg\")
\u201cSuch planning wastes valuable time and funding resources that should be used for developing the EUS from the beginning so that it will be available for all crewed SLS missions.<\/p>\n\u201cTo ensure proper funding, the Committee provides $1,900,000,000 in fiscal year 2016 for SLS, with no less than $100,000,000 provided for the direct development of the EUS to be used for EM-2.<\/p>\n
\u201cThis funding level is necessary in order for the SLS to continue its progress towards a successful EM\u20131 launch as early as possible in 2018, to facilitate development of essential EUS propulsion hardware, and to begin the procurement process of long lead items for a crewed launch in 2021.\u201d<\/p>\n
The SLS teams are waiting for the language to become law, allowing them to press on with the EUS study work and install it into SLS\u2019 plans.<\/p>\n
![\"2015-06-30-131229\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2015\/06\/2015-06-30-131229-350x247.jpg\")
Additional problems with having to start with an interim Upper Stage are also impacting on other elements associated with SLS, such as the Mobile Launcher.<\/p>\nThe ML\u2019s conversion from its role with the defunct Ares I launch vehicle are almost complete.<\/p>\n
However, its array of umbilicals and connections are being worked with the ICPS in mind.<\/p>\n
No design work has been approved for SLS using the EUS, although the changes between the SLS using DCSS and EUS wouldn\u2019t be too drastic.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/11\/Z8.jpg\")
It is understood that SLS\u2019s Crew Access Arm (CAA) and the Orion Service Module Umbilical (OSMU) \u2013 which will provide electrical, data, and purging processes to Orion\u2019s Service Module \u2013 will be moved up the launch tower to match the Orion\u2019s position on the stack with the EUS.<\/p>\nAll the core stage arms and stabilizer will remain exactly as they are in the original plan, while there will be a new second stage hydrogen vent arm, similar or identical to the Core Stage Forward Skirt Umbilical arm.<\/p>\n
However, the second stage LOX and LH2 umbilical arms will likely require a redesign during the switch.<\/p>\n
Other considerations include the engines that will be used on the EUS.<\/p>\n
Evaluations into the EUS have already reached the Point of Depature (POD) stage, baselining the SLS Block IB Upper Stage with four RL-10-C1 engine stage \u2013 a switch away from the now defunct J-2X engines \u2013 with a maximum propellant load of 285,000 lbm.<\/p>\n
![\"Z3\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2014\/06\/Z31.jpg\")
Per the POD overview (L2), the EUS will carry a length NTE (Not To Exceed) 60 ft, an LH2 tank diameter of 8.4 m, and a LOX tank diameter of 5.5 m.<\/p>\nWhile it is likely the RL-10s will be the engine of choice, other options include utilizing four MB-60 engines \u2013 which would provide even more power to the stage.<\/p>\n
It has also been suggested that the Block 1B version of SLS, sporting the EUS and advanced boosters could provide all the required upmass capability NASA envisions for the rocket, which would allow for the funds allocated for the final evolution to the Block 2 SLS being redirected into payloads and missions.<\/p>\n
(Images: L2\u2019s SLS Sections and L2 artist Nathan Koga for some of the EUS and SLS in her correct color scheme of an unpainted core.)<\/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":"
NASA officials have admitted the interim Upper Stage for the Space Launch System is at the top of their \u201cworry list\u201d, as the Agency\u2019s key advisory group insists NASA should make a decision about bringing the more powerful Exploration Upper Stage (EUS) online sooner. The Aerospace Safety Advisory Panel (ASAP) fears NASA is at risk […]<\/p>\n","protected":false},"author":1,"featured_media":30107,"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":[8862,8075,624],"class_list":["post-39302","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-asap","tag-eus","tag-sls"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/39302"}],"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=39302"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/39302\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/30107"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=39302"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=39302"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=39302"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}