Agree with combustion stability and weight items. Also a way to get some economy of scale in producing more of the same thing.
Hi! This is a stupid newbie with a stupid newbie question, so feel free to throw popcorn at me.I have a question about optimal acceleration profiles for a rocket lifting off from Earth's surface into low Earth orbit. Say the rocket has a thrust-to-weight ratio way above 1 and an unreasonably high specific impulse of 20,000 seconds or so (NSWR, don't ask) so it is a single stage to orbit rocket. The engine can be throttled so the acceleration can be varied as the rocket loses mass.Given that it is undesirable for the acceleration to rise above 4g or so in order to prevent damage to the astronauts.Also given that every second spent in transit to orbit imposes a "gravity tax" of a 9.81 m/s reduction in speed so it is desirable to minimize the transit duration.So the question is: with these givens, what sort of acceleration profile over the transit duration would be optimal?
Also given that every second spent in transit to orbit imposes a "gravity tax" of a 9.81 m/s reduction in speed so it is desirable to minimize the transit duration.
How is C3 calculated? I understand Dv, but C3 is beyond me..Thanks,JR
How is C3 calculated? I understand Dv, but C3 is beyond me..
Does http://en.wikipedia.org/wiki/Specific_orbital_energy help?
Hey this is just a quick question.Why do rockets not use the same expanding nozzle technology used in fighter jet aircraft?
Quote from: joertexas on 02/24/2012 05:56 pmHow is C3 calculated? I understand Dv, but C3 is beyond me..I got a few answers re C3 here (and subsequent pages):-http://forum.nasaspaceflight.com/index.php?topic=13543.msg521874#msg521874cheers, Martin
Quote from: DarkenedOne on 02/25/2012 05:16 pmHey this is just a quick question.Why do rockets not use the same expanding nozzle technology used in fighter jet aircraft?Exhaust is hotter and at higher pressure