That's wrong. Vulcain 2 on Ariane 5 flew four times in 2013. It's a 1340 kN thrust LOX-hydrogen engine. By contrast the J-2X will have 1307 kN. Also the F-1 en

That's wrong. Vulcain 2 on Ariane 5 flew four times in 2013. It's a 1340 kN thrust LOX-hydrogen engine. By contrast the J-2X will have 1307 kN. Also the F-1 engine has been surpassed in thrust and efficiency by the Russian RD-170 family which flies today in the Zenit rocket. I'm sure you could learn a lot from studying the J-2 and J-2S. No harm in that. But mystifying Apollo has done a lot of harm to sane space technology engineering and policy. Sources: http://www.arianespace.com/news-launch-logs/2013-2014.asp http://www.arianespace.com/news-launch-logs/2013-2014.asp http://www.sea-launch.com/missions-q1-past_launches.aspx http://www.sea-launch.com/missions-q1-past_launches.aspx http://www.spacelaunchreport.com/log2013.html http://www.spacelaunchreport.com/log2013.html