As first reported on this website, NASA is considering changing the baseline LOX\/methane engine for the Crew Exploration Vehicle (CEV) Service Module \u2013 and the Lunar Surface Access Module\u00e2\u20ac\u2122s (LSAM) ascent stage \u2013 to a hypergolic or hydrocarbon engine. <\/p>\n
The specter of the removal of methane has raised some concerns in the aerospace community, mainly because the ESAS team considered it to be ideally suited to the task of acting as the fuel for the CEV and LSAM ascent stages.\n<\/p>\n
Because methane could be manufactured in-situ on Mars, it is both more efficient and much safer than hypergolics \u2013 while it is much denser and more storable than liquid hydrogen, Dr. Doug Stanley, the ESAS Lead, believes that the decision to drop the methane engine could create long-term problems for the ESAS. \u2018I believe dropping methane in favor of hypergols would not make sense for a number of reasons,\u2019 he said. <\/font><\/p>\n \u00e2\u20ac\u0153The effect on the total architecture and sustainability must be properly weighed.\u00e2\u20ac\u009d <\/font><\/p>\n A switch to hypergolic fuels would prevent lunar ISRU, because liquid oxygen extracted from the lunar regolith or mined from suspected lunar ice could no longer be used as rocket propellant. Dr. Stanley believes that in the long term this could increase the life-cycle cost of the lunar landers used to support a base. <\/p>\n \u2018Eventually the lunar lander will be re-used in a single stage (hopefully with LOX ISRU),\u2019 he explained, while a lack of liquid oxygen-fueled engines would make such a design much more expensive to operate because fuels would have to hauled all the way from Earth.<\/p>\n Because a methane\/oxygen system is more efficient than hypergolic propellants, Dr. Stanley believes that using hypergolics will vastly increase the mass of the CEV. <\/font><\/p>\n \u2018Switching from methane to hypergols could add about 1500 lb to the CEV system weight,\u00e2\u20ac\u009d he said. Additionally, \u00e2\u20ac\u0153[the] LSAM weight could grow over 3klbs to provide [the] same payload capability [to the lunar surface].\u2019 <\/font><\/p>\n However, Dr. Stanley says that a third alternative, a LOX\/ethanol-fueled system, is still in the running for the CEV\/LSAM engines. <\/font><\/p>\n \u2018LOX\/ethanol is very much on the table and preferred by many in NASA,\u2019 he said. Because ethanol has a higher Isp than hypergolic propellants \u2013 and is about ten times denser than liquid hydrogen \u2013 \u00e2\u20ac\u0153switching to another LOX\/hydrocarbon would not add nearly as much [mass],\u2019 to the CEV system as would a switch to traditional storables, he explained.<\/font><\/p>\n Rocket building kits (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n However, ethanol is still not as efficient as methane, and a switch to LOX\/ethanol for the CEV would still increase combined CEV and LSAM mass by \u2018a couple of thousand pounds\u2019, Dr. Stanley noted. <\/p>\n Because of this, he hopes to verify that top-level NASA management is properly considering all alternatives in the coming weeks. <\/font><\/p>\n He added that the jury on the CEV\/LSAM propulsion system is still out. <\/font><\/p>\n \u2018The final decision on green [hydrocarbon fuels] vs. hypergols has not been made.\u2019<\/p>\n <\/font>For updates and debate, head to our CLV\/CEV section: As first reported on this website, NASA is considering changing the baseline LOX\/methane engine for the Crew Exploration Vehicle (CEV) Service Module \u2013 and the Lunar Surface Access Module\u00e2\u20ac\u2122s (LSAM) ascent stage \u2013 to a hypergolic or hydrocarbon engine. The specter of the removal of methane has raised some concerns in the aerospace community, mainly […]<\/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":[],"class_list":["post-42159","post","type-post","status-publish","format-standard","hentry","category-news"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/42159"}],"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=42159"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/42159\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=42159"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=42159"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=42159"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/font><\/em>http:\/\/forum.nasaspaceflight.com\/forums\/forum-view.asp?fid=5<\/font><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"