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The article doesn't mention SpaceX, I wonder what's the difference in energy and cost for launching (and landing) the relative stage 1s. Does anyone have an idea on that?
Earlier quoted context omitted.
The less air you are pushing the cheaper it is to achieve that delta-V
Is it really that dramatic a difference? I suppose it must be, if they're building it, but it's strange that no one has done this before if it really helps.
Earlier quoted context omitted.
The less air you are pushing the cheaper it is to achieve that delta-V
Is it really that dramatic a difference? I suppose it must be, if they're building it, but it's strange that no one has done this before if it really helps.
I'm confused as to what this thing can accomplish. It can probably fly very high, but I assume it can't fly very fast (relative to orbital speed), and I thought the overwhelming majority of the delta-V to get something into orbit was for forward momentum and that just launching from higher up wouldn't help much. Clearly there's something I'm missing here (or they wouldn't have built it), can anyone fill me in?
The majority of the horizontal delta-V is produced in the second stage. The job of the first stage is to a large extent just to lift the second stage out of the densest part of the atmosphere, to minimize drag for the second stage. A plane can do the same thing, and possibly more cheaply in certain scenarios (well, that has to be Allen's plan anyway).
Earlier quoted context omitted.
The less air you are pushing the cheaper it is to achieve that delta-V
Is it really that dramatic a difference? I suppose it must be, if they're building it, but it's strange that no one has done this before if it really helps.
[0] https://en.wikipedia.org/wiki/Air_launch_to_orbit
[1] https://en.wikipedia.org/wiki/Pegasus_(rocket)#Launch_histor...
1. +230m/s orbital velocity [1]
2. +9km launch altitude [1]
3. can launch in more weather conditions
4. 1st stage can abort mid-launch without loss of payload.
Of these, the most important is the increase in launch altitude, because that means stage 2 launches in air of greatly decreased density, leading to the following efficiencies:
A. a vacuum-optimized nozzle can be used, increasing engine performance
B. less aerodynamic/drag energy losses
C. max Q should be lower, allowing full throttle usage, reducing mass needed for structural elements, and reducing vibration stresses on payload
P.S. Thank you KSP for teaching me this stuff! :D
Bonus: video of pegasus air launched rocket: https://www.youtube.com/watch?v=jz_5hnIw2jc
The article doesn't mention SpaceX, I wonder what's the difference in energy and cost for launching (and landing) the relative stage 1s. Does anyone have an idea on that?
Earlier quoted context omitted.
The less air you are pushing the cheaper it is to achieve that delta-V
Is it really that dramatic a difference? I suppose it must be, if they're building it, but it's strange that no one has done this before if it really helps.
https://en.m.wikipedia.org/wiki/Scaled_Composites_White_Knig...