<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>_ph_</author><text>While the article was focused on the Raptor engine, it shows how great an engine the RS-25 of the space shuttle was. It was crazy expensive, but as the shuttle was reused, one could justify the cost. The sad thing is, this engine will be used in the SLS - with no reuse what so ever. If anything describes the insanity of the SLS system, then this. They are flying the most expensive rocket engine ever in fully disposable mode. Even worse. After ending the shuttle program, the engines were of course preserved, so at least the first SLS flights are going to waste the origininal shuttle engines.</text><parent_chain></parent_chain></comment><story><title>SpaceX Raptor: Methane fueled full-flow staged combustion cycle engine</title><url>https://everydayastronaut.com/raptor-engine/</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>ncmncm</author><text>Seems like with as many F1s as were used on each Apollo mission, he should count more than 17 flights. Also, I know at least one F1 was shut down before reaching orbit.&lt;p&gt;But, wow, what a great presentation! None of the other explanations I read of the full-flow design were anywhere near as clear and comprehensible. My understanding of rocket design principles has taken a great leap.</text><parent_chain></parent_chain></comment><story><title>SpaceX Raptor: Methane fueled full-flow staged combustion cycle engine</title><url>https://everydayastronaut.com/raptor-engine/</url></story>