Stratolaunch Carrier unveiled - its huge!!

[CAT-THE-FIFTH]

Wow,this is one massive aircraft:

http://www.space.com/37046-stratolau...t-rollout.html

Apparently the payload is around 225000KG.

[Corky34]

I don't get it, i thought getting into orbit was more about going fast enough than the height, obviously the guys working for Paul Allen know better but I'd love to know what the advantage is of launching from a plane at 30k feet is.

[CAT-THE-FIFTH]

More pictures:

https://arstechnica.com/science/2017...day-it-is-big/

I don't get it, i thought getting into orbit was more about going fast enough than the height, obviously the guys working for Paul Allen know better but I'd love to know what the advantage is of launching from a plane at 30k feet is.

It might be an air density thing??

[kompukare]

I don't get it, i thought getting into orbit was more about going fast enough than the height, obviously the guys working for Paul Allen know better but I'd love to know what the advantage is of launching from a plane at 30k feet is.

From https://en.wikipedia.org/wiki/Air_la...bit#Advantages
"The principal advantage of a rocket being launched by a high flying airplane is that it need not fly through the low, dense atmosphere, the drag of which requires a considerable amount of extra work and thus mass of propellant. Higher densities at lower altitudes result in larger drag forces acting on the vehicle... "

There's more in the Wiki plus a large disadvantages section too. Guess it is at least different thinking compared to normal rockets. Not as radical as a space elevator though or some of the other non-rocket spacelaunch ideas.

[Xlucine]

Rockets have to carry oxidiser, which means more fuel to shift the weight of the oxidiser, which means more oxidiser to burn it... etc. Using an air breathing engine for the portion of the flight that allows it is far more efficient. Also, the engines for the initial flight are much bigger than the upper stage engines, and so more expensive - if you can't re-land them like spaceX does, then avoiding use of them entirely cuts cost significantly

[Biscuit]

I think just the same as with hardware.... ill wait for version 2

[Jonj1611]

How that doesn't snap in the middle I will never know

[DanceswithUnix]

Rockets have to carry oxidiser, which means more fuel to shift the weight of the oxidiser, which means more oxidiser to burn it... etc. Using an air breathing engine for the portion of the flight that allows it is far more efficient. Also, the engines for the initial flight are much bigger than the upper stage engines, and so more expensive - if you can't re-land them like spaceX does, then avoiding use of them entirely cuts cost significantly

That is the idea behind the Reaction Engines design, burn air where you can and oxidiser where you must.
The thing with the plane is, it is going to top out at something like 600mph which in rocket terms is hardly moving. The rocket needs to get you the other 16400mph to reach orbital velocity. Now 600mph is a pretty small percentage of 17000mph, but should we be thinking in terms of work done on the rocket by the engine to increase kinetic energy? If that is the case, the half em vee squared energy in a couple of tonnes doing 17000mph makes 600mph look laughable. Not sure about that, my electronics degree was good but didn't include rocket science
The Reaction Engines design uses air at very high speed, which if they can pull the trick off is way more elegant.

Musk claims that propellant isn't such a significant cost compared to dropping all your hardware in the sea during launch.

[ik9000]

How that doesn't snap in the middle I will never know

Reminds of this from when I was little:

[Jonj1611]

Maybe thats where they got the design from

[ik9000]

That is the idea behind the Reaction Engines design, burn air where you can and oxidiser where you must.
The thing with the plane is, it is going to top out at something like 600mph which in rocket terms is hardly moving. The rocket needs to get you the other 16400mph to reach orbital velocity. Now 600mph is a pretty small percentage of 17000mph, but should we be thinking in terms of work done on the rocket by the engine to increase kinetic energy? If that is the case, the half em vee squared energy in a couple of tonnes doing 17000mph makes 600mph look laughable. Not sure about that, my electronics degree was good but didn't include rocket science
The Reaction Engines design uses air at very high speed, which if they can pull the trick off is way more elegant.

Musk claims that propellant isn't such a significant cost compared to dropping all your hardware in the sea during launch.

SCRAMjet and RAM jet technology. I'm not sure if you need an intermediate stage to get supersonic first but once you have enough speed conventional air friction can be chanelled and used to ingite the solid fuel stage to get hypersonic. E.g. Russia is apparently successfully using it already: https://uk.news.yahoo.com/russia-suc...142408335.html *


*Caution the accreditation for that is Rob Waugh but I don't think this is the only example of this, just I happened to stumble across it this morning.