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The DIRECT proposal has its roots in the Marshall Space Flight Center (MSFC) studies (1990s) to design a shuttle-based heavy lift cargo vehicle to compliment the space shuttle. Known as the National Launch System (NLS), the concept was deemed to have significant merit \u2013 before being deleted due to budgetary concerns.<\/p>\n
In 2006, a group of engineers and members of the space community revived and modernized the concept, calling it DIRECT.<\/p>\n
The proposal was first presented in October 2006, followed by a major revision in September 2007, known as DIRECT 2.0. The team claims to be comprised of eight public representatives and 62 NASA and contractor engineers \u2013 who work on the project on their own time.<\/p>\n
NASA Analysis Background:<\/p>\n
NASA educational resources
<\/path>Spaceflight history books <\/path>Aerospace industry analysis <\/path>\n (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n
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As DIRECT gained attention via two AIAA papers, and presentations at the ISDC, before MSFC performed two reviews of the DIRECT 2.0 architecture in May and October of 2007 \u2013 which found serious issues with DIRECT\u2019s performance and capabilities.<\/p>\n\u201cAnalysis of the DIRECT architecture shows significant performance shortfall in assessed capability,\u201d noted the October, 07 analysis.<\/p>\n
\u201cThe DIRECT architecture aggressively estimates its stage dry mass predictions, which results in optimistic in-space performance. Consequently, the Direct 2.0 would likely be a Three Vehicle Launch Solution Mission to accomplish the Project Constellation Payload Requirements with NASA design margins, ground rules and assumptions.<\/p>\n
\u201cAssessed performance has improved from May 2007 EOR-LOR, but still fails to meet minimum requirements by at least 50 percent of needed Lander Payload.\u201d<\/p>\n
In order to back up these claims, NASA commissioned a \u2018Team B\u2019 review to attempt to design and fly a DIRECT lunar mission using NASA tools and specifications. Their results showed significantly larger masses and lower performance predictions, than those claimed by DIRECT.<\/p>\n
\u201cDIRECT currently unsuitable for its proposed goal of replacing the Ares I\/V architecture to carry out the earth-to-TLI transportation functions for the Constellation Programs,\u201d noted the review.<\/p>\n
![\"a91\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/05\/a91.jpg\" "\\"a91\\"")
The analysis also attacks the infrastructure and development of the DIRECT vehicles, specifically DIRECT\u2019s claimed redesign of the External Tank vs. Ares I\u2019s clean sheet upper stage.<\/p>\n\u201cAssessment of design would lead to major redesign, development and qualification of Mod ET Core for Jupiter 232 missions. Predicted touch labor of Ares 1 Upper Stage estimated to be significantly less than current ET touch labor.<\/p>\n
\u201cExamined approaches like this in the past 20 years: Concluded that this effort incurs significant expense and development with marginally applicable STS ET heritage.<\/p>\n
\u201cThe Jupiter common core requires a new: Main Propulsion System, thrust structure, avionics, forward LOX tank structure and a payload shroud, substantial intertank\/LH2 modifications, and a stack integration effort.<\/p>\n
The October 07 analysis\u2019 final major criticism of DIRECT referenced Ares\u2019 operational safety and simplicity.<\/p>\n
\u201cDIRECT launch architecture requires increased number of spacecraft separations and dockings for all phases, increasing risk Separation, flip around and docking of Orion to Altair Rendezvous and docking of Orion-Altair stack to first EDS pre-TLI burn. DIRECT shows a 1\/1400 PLOC for Jupiter 232 Lunar\/Mission.<\/p>\n
DIRECT\u2019s Rebuttal:<\/p>\n
DIRECT\u2019s response to NASA\u2019s analysis is forthcoming via a 100+ page rebuttal document that deals with the claims and explains why the criticisms are flawed \u2013 according to DIRECT. *CLICK HERE TO DOWNLOAD THE PRESENTATION*<\/p>\n
![\"a47\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/05\/a47.jpg\" "\\"a47\\"")
The document centers around the allegation that DIRECT was significantly misinterpreted by NASA\u2019s analysis teams in an attempt to discredit the proposal.<\/p>\n\u201cNASA\u2019s October 2007 analysis of DIRECT, on the surface, appears to be a carefully executed analysis of the DIRECT architecture and its central launch vehicle, Jupiter,\u201d notes the rebuttal document.<\/p>\n
\u201cHowever, a closer examination of the document reveals significant flaws in the evaluation of DIRECT that sets up a scenario where DIRECT would inevitably look inferior when compared to Ares.<\/p>\n
\u201cThe errors are so numerous that the only conclusion possible is that this document was not a true analysis, but rather an attempt to discredit the DIRECT architecture.\u201d<\/p>\n
DIRECT claims that NASA\u2019s inability to match the DIRECT team\u2019s claimed performance hinges on the arbitrary mass increase of the EDS (Earth Departure Stage) by \u2018Team B\u2019.<\/p>\n
\u201cFor Every 1 kg Upper Stage Growth, 3 kg Less Payload Delivered through TLI. Arbitrarily increasing the mass of the Upper Stage penalizes the performance of the entire system 3-fold.<\/p>\n
\u201cOn pages 55 & 56 of NASA\u2019s Analysis, a breakdown of the mass of the Upper Stage shows NASA\u2019s \u2018Case #2 \u2013 Team B\u2019 design methodology using INTROS, results in a 17,797kg difference in burnout mass for the Upper Stage; 23,062 kg vs. 40,859 kg \u2013 a 77 percent performance penalty.<\/p>\n
\u201cA penalty applied to the Upper Stage mass of nearly 18mT results in a net reduction of EDS lunar performance by nearly 36mT.\u201d<\/p>\n
DIRECT contends that this mass increase is due to the use of a NASA design tool that does not assume the Centaur-based components of DIRECT\u2019s upper stage.<\/p>\n
\u201cNASA\u2019s Upper Stage was designed using the NASA-developed \u201cINTROS\u201d tool,\u201d claims the rebuttal. \u201cWhile this is based on heritage data, this tool has never been utilized in the production of any flying vehicle to date. Boeing did not utilize the tool for its Delta-IV and Lockheed Martin did not utilize the tool for the Atlas V \u2013 the two most modern US launchers.<\/p>\n
\u201cNASA\u2019s analysis (also) ignores DIRECT\u2019s plan to use a Common Bulkhead design for the Jupiter Upper Stage.\u201d<\/p>\n
![\"a57\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/05\/a57.jpg\" "\\"a57\\"")
The DIRECT team also attempt to back up their claims that the External Tank (ET) would only have to undergo minor redesign \u2013 which is an area of contention due to claims DIRECT ignore the testing requirements any changes to the ETs require \u2013 by noting the \u201cminor\u201d claim is comparative to the \u201cmajor\u201d changes required by Ares I and Ares V.<\/p>\n\u201cIt is worth noting that the requirement to build two new SRB designs, a vast new 10m Core Stage, two new Upper Stages and two completely separate production and launch processing infrastructures to support both Ares I \u2013 and then Ares V \u2013 would certainly qualify as a \u201cmajor\u201d undertaking,\u201d DIRECT claim \u2013 adding they would also save billions in development costs.<\/p>\n
\u201cIn that single context, it might be accurate to describe DIRECT\u2019s plans as comparatively<\/em> \u2018minor\u2019.<\/p>\n
\u201cDevelopment costs for Jupiter-120 are approximately $5,000m lower than Ares I. Development costs for Jupiter-232 are a further $9,000m lower than Ares V. Operations costs for two very different Ares vehicles are approx. $3,100m higher per year than for the common-core Jupiter\u2019s. Total DIRECT lifecycle savings thru 2020 are greater than $19,000m.\u201d<\/p>\n
To address NASA\u2019s last major criticism concerning safety and operations, DIRECT points out that the risk calculations have been easily skewed, and are essentially subjective.<\/p>\n
\u201cThere is a \u2018time factor\u2019 at work also which severely skews NASA\u2019s conjecture. The Jupiter\u2019s LOC (Loss Of Crew) and LOM (Loss Of Mission) figures were calculated in late October 2007,\u201d DIRECT claim. \u201cThis date coincides with the Ares I Integrated System Technical Interchange Meeting (IS-TIM) on November 8.<\/p>\n
\u201cThe design of Ares I has not changed significantly since that time, only the methodology for calculating the risk has altered since then. Somehow Ares I has doubled its LOC claims to \u201c1\/2400\u2033 \u2013 according to NASA, yet the Ares I still uses all the same engines and stages.\u201d<\/p>\n
However, it appears DIRECT completely ignore the central claim by Constellation that their first stage SRB has obvious safety benefits when compared to Jupiter\u2019s \u201cnumerous moving parts\u201d in its first stage liquid engines. DIRECT also admit they are still awaiting new analysis.<\/p>\n
\u201cAt time of writing, DIRECT is still awaiting results of a new analysis and expects similar improvements as Ares,\u201d the rebuttal admits.<\/p>\n
![\"a541\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/05\/a541.jpg\" "\\"a541\\"")
DIRECT claim that they would have lower total mission risk due to its capability to return safety systems that have been stripped of Orion due to mass issues.<\/p>\n\u201cBecause of DIRECT\u2019s surplus performance, all <\/em>of the capabilities deleted from Orion in the Zero Base Vehicle (ZBV) studies could be added back in,\u201d they claim.<\/p>\n
\u201cIf those systems can be reintegrated, it would dramatically improve the overall mission LOM figures, which represent a far larger portion of the total risks than just the launch.\u201d<\/p>\n
DIRECT anticipates being heavily involved in the upcoming Blue Ribbon review for human space flight \u2013 which will include an evaluation on NASA\u2019s current exploration direction \u2013 and the team will be presenting their latest proposals at the Orlando ISDC conference at the end of May and will also have representatives there able to discuss the latest evolutions of the proposal.<\/p>\n","protected":false},"excerpt":{"rendered":"
The team behind the alternative exploration architecture known as DIRECT have released a rebuttal document, countering claims made by NASA\u2019s Constellation Program, ahead of the Blue Ribbon review for human space flight. The document specifically targets a series of claims made by a NASA team in May and October of 2007, which found the Jupiter […]<\/p>\n","protected":false},"author":1,"featured_media":0,"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":[9206,8184],"class_list":["post-41100","post","type-post","status-publish","format-standard","hentry","category-news","tag-direct","tag-sls-orion"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41100"}],"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=41100"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/41100\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=41100"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=41100"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=41100"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}