{"id":181829,"date":"2016-03-06T20:00:00","date_gmt":"2016-03-07T01:00:00","guid":{"rendered":"https:\/\/www.panix.com\/~msaroff\/40years\/2016\/03\/06\/a-little-rocketry-factoid\/"},"modified":"2016-03-06T20:00:00","modified_gmt":"2016-03-07T01:00:00","slug":"a-little-rocketry-factoid","status":"publish","type":"post","link":"https:\/\/www.panix.com\/~msaroff\/40years\/2016\/03\/06\/a-little-rocketry-factoid\/","title":{"rendered":"A Little Rocketry Factoid"},"content":{"rendered":"<p>I was reading an article about how <a href=\"http:\/\/aviationweek.com\/space\/france-pursues-low-cost-reusable-loxmethane-engine\">France is looking into creating a reusable rocket engine powered by Lox\/CH<sub>4<\/sub><\/a>. (Methane)<\/p>\n<p>I was wondering why they would go with Methane as a fuel, so I did some reasons.<\/p>\n<p>These days, there are 4 basic options for launcher fuel, Liquid Hydrogen, Kerosene (RP-1), Hydrazine, and Methane.<\/p>\n<p>Hydrazine has fallen out of favor for boosters, though it is still used in thrusters of various sorts.  It has low impulse, and it&#8217;s toxic, but the fact that it can be used as a monopropellant means that it is convenient to use for orbital maneuvering, since it requires half the parts, and you don&#8217;t need to make sure that the flow of a separate fuel and oxidizer are synchronized for short the &#8220;blip&#8221; that would be needed for an orbital rendezvous or station keeping.<\/p>\n<p>The commonly used propellants are LH<sub>2<\/sub> and RP-1 each have distinct advantages:<\/p>\n<ul>\n<li>Hydrogen has the highest impulse (fuel economy).<\/li>\n<li>RP-1 is denser, and requires smaller tanks.<\/li>\n<li>RP-1 can be stored at room temperature.<\/li>\n<\/ul>\n<p>Methane falls in between Hydrogen and RP-1.  It&#8217;s less dense than RP-1, and more dense than LH<sub>2<\/sub>, and is more fuel efficient than RP-1 and less so than LH<sub>2<\/sub>.<\/p>\n<p>Methane is also a lot easier to handle than LH<sub>2<\/sub>, with hydrogen condensing at -252.9\u00b0C, while liquefies at a relatively balmy -161.6\u00b0C, much closer to the boiling point of LOX. (-183\u00b0C)<\/p>\n<p>Additionally, for reusable and restartable engines, Methane has the advantage that it does not coke up, so recycling the engine for another use is more straightforward than RP-1.<\/p>\n<p>Additionally, if you want to go to Mars or the outer planets, it is relatively trivial to manufacture or extract Methane, while manufacturing LH<sub>2<\/sub> would be <b>extremely<\/b> difficult, and manufacturing RP-1 would be nigh impossible.<\/p>\n<p>So, now you know more than you want to about why a number of rocket manufacturers are looking into Methane as a propellant.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I was reading an article about how France is looking into creating a reusable rocket engine powered by Lox\/CH4. (Methane) I was wondering why they would go with Methane as a fuel, so I did some reasons. These days, there are 4 basic options for launcher fuel, Liquid Hydrogen, Kerosene (RP-1), Hydrazine, and Methane. Hydrazine &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1128,1037,1025],"tags":[],"class_list":["post-181829","post","type-post","status-publish","format-standard","hentry","category-propulsion","category-space","category-technology"],"_links":{"self":[{"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/posts\/181829"}],"collection":[{"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/comments?post=181829"}],"version-history":[{"count":0,"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/posts\/181829\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/media?parent=181829"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/categories?post=181829"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.panix.com\/~msaroff\/40years\/wp-json\/wp\/v2\/tags?post=181829"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}