Help Needed - Launch Vehicle Design

[jnc]

the J-2X Engine Development Blog

Oooh, thanks for the tip to the existence of that. (Here, for those who are interested.)

Noel

[Nittany Lion]

I suggest reading the latest post to the J-2X Engine Development Blog at blogs.nasa.gov.

Thanks from me too! Looks like everything I ever wanted to know about the J-2X.

[notsorandom]

That blog is quite the gold mine. I have enjoyed reading it so much through the past few years that I want to see the J-2X used for something! Even though it looks like with things the way they are it will have a pretty limited use.

[edkyle99]

Does anyone really believe that Falcon 9 Heavy can lift 66,000 pounds more to orbit than Delta IV Heavy while using lower ISP propellants?

I don't believe that the Falcon Heavy that SpaceX has described can lift 53 tonnes to LEO, but the trick the company has used more than once now is to publicize a payload goal while developing a Block 1 rocket that won't actually achieve the goal.  Everyone studies the rocket on the launch pad while scratching their heads, but they are looking at what is in effect a ruse.  It is the follow-on design, or the follow-on after that, that aim toward the announced goal. 

 - Ed Kyle

[Jason1701]

Does anyone really believe that Falcon 9 Heavy can lift 66,000 pounds more to orbit than Delta IV Heavy while using lower ISP propellants?

I don't believe that the Falcon Heavy that SpaceX has described can lift 53 tonnes to LEO, but the trick the company has used more than once now is to publicize a payload goal while developing a Block 1 rocket that won't actually achieve the goal.  Everyone studies the rocket on the launch pad while scratching their heads, but they are looking at what is in effect a ruse.  It is the follow-on design, or the follow-on after that, that aim toward the announced goal. 

 - Ed Kyle

I think the consensus on the SpaceX board is that the 53 t FH uses 1.1 cores, not 1.0. These are significantly stretched.

[edkyle99]

Does anyone really believe that Falcon 9 Heavy can lift 66,000 pounds more to orbit than Delta IV Heavy while using lower ISP propellants?

I don't believe that the Falcon Heavy that SpaceX has described can lift 53 tonnes to LEO, but the trick the company has used more than once now is to publicize a payload goal while developing a Block 1 rocket that won't actually achieve the goal.  Everyone studies the rocket on the launch pad while scratching their heads, but they are looking at what is in effect a ruse.  It is the follow-on design, or the follow-on after that, that aim toward the announced goal. 

 - Ed Kyle

I think the consensus on the SpaceX board is that the 53 t FH uses 1.1 cores, not 1.0. These are significantly stretched.

Even with v1.1 cores I don't believe the numbers.  Something else is needed.  It would still start out to be a very capable launcher, but 40-something rather than 53 tonnes.

 - Ed Kyle

[Prober]

Your reading material

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710019929_1971019929.pdf

[vulture4]

Your reading material

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710019929_1971019929.pdf

Good book but many pages are unreadable due to scanning problems. I am not aware of an operational rocket using propellant crossfeed despite the ancient lineage of the concept (I believe it was mentioned by Robert Goddard). The complexity of the pumps and lines required for crossfeed would have to would have to be balanced against the alternative method of putting a fully-fueled stage at altitude - simply making it the second stage. The latter method has the obvious advantage that expansion ratio and even propellant combination can be optimized for the upper stage pressure/velocity regime.