Benefits of air-launching a rocketWhy aren't all satellite-carrying rockets launched from airplanes?Is the “airship to orbit” mission profile feasible?Why aren't all satellite-carrying rockets launched from airplanes?Is the “airship to orbit” mission profile feasible?Why are spacecraft not air-launched from airplanesRange safety for air-launch vehiclesFloating LaunchShould all the Air-Launch systems be deployed at sub-sonic speeds?Is it coincidence that the Electron has very similar dimensions to the Pegasus?Air-launching an Electron-like LOX-based rocket from a plane; technical challenges?All dressed up and no place to go; who will be Stratolauncher's aircraft-launched rocket?

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Benefits of air-launching a rocket


Why aren't all satellite-carrying rockets launched from airplanes?Is the “airship to orbit” mission profile feasible?Why aren't all satellite-carrying rockets launched from airplanes?Is the “airship to orbit” mission profile feasible?Why are spacecraft not air-launched from airplanesRange safety for air-launch vehiclesFloating LaunchShould all the Air-Launch systems be deployed at sub-sonic speeds?Is it coincidence that the Electron has very similar dimensions to the Pegasus?Air-launching an Electron-like LOX-based rocket from a plane; technical challenges?All dressed up and no place to go; who will be Stratolauncher's aircraft-launched rocket?













5












$begingroup$


Is there a way to quantify how much you would gain by air-launching a rocket compared to a ground launch?










share|improve this question









$endgroup$







  • 1




    $begingroup$
    Possible duplicates: Why aren't all satellite-carrying rockets launched from airplanes?, Is the “airship to orbit” mission profile feasible?
    $endgroup$
    – DarkDust
    Apr 22 at 14:14
















5












$begingroup$


Is there a way to quantify how much you would gain by air-launching a rocket compared to a ground launch?










share|improve this question









$endgroup$







  • 1




    $begingroup$
    Possible duplicates: Why aren't all satellite-carrying rockets launched from airplanes?, Is the “airship to orbit” mission profile feasible?
    $endgroup$
    – DarkDust
    Apr 22 at 14:14














5












5








5





$begingroup$


Is there a way to quantify how much you would gain by air-launching a rocket compared to a ground launch?










share|improve this question









$endgroup$




Is there a way to quantify how much you would gain by air-launching a rocket compared to a ground launch?







air-launch






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Apr 22 at 13:17









HobbesHobbes

96.7k2272427




96.7k2272427







  • 1




    $begingroup$
    Possible duplicates: Why aren't all satellite-carrying rockets launched from airplanes?, Is the “airship to orbit” mission profile feasible?
    $endgroup$
    – DarkDust
    Apr 22 at 14:14













  • 1




    $begingroup$
    Possible duplicates: Why aren't all satellite-carrying rockets launched from airplanes?, Is the “airship to orbit” mission profile feasible?
    $endgroup$
    – DarkDust
    Apr 22 at 14:14








1




1




$begingroup$
Possible duplicates: Why aren't all satellite-carrying rockets launched from airplanes?, Is the “airship to orbit” mission profile feasible?
$endgroup$
– DarkDust
Apr 22 at 14:14





$begingroup$
Possible duplicates: Why aren't all satellite-carrying rockets launched from airplanes?, Is the “airship to orbit” mission profile feasible?
$endgroup$
– DarkDust
Apr 22 at 14:14











1 Answer
1






active

oldest

votes


















7












$begingroup$

I came across a fairly detailed comparison made by the team that worked on Interim HOTOL.



Delta-v required for a vertical launch SSTO (e.g. Delta Clipper) to LEO: 9361 m/s



For Interim Hotol:



  • speed supplied by launch aircraft (An-225), launching at Mach 0.8 at 9 km altitude: - 235 m/s

  • drag loss: + 67 m/s

  • gravity losses: - 670 m/s

  • Isp underexpansion losses at low altitude: - 180 m/s

  • Thrust vectoring demands: + 10 m/s

  • Improved engine Isp due to altitude start: - 214 m/s

for a total reduction in delta-V of 1222 m/s, or 13%, translating into a 24% reduction in propellant requirement.



From the book 'Spaceflight in the era of aero-space planes' (R. Hannigan, Krieger publishing, 1994).






share|improve this answer









$endgroup$












  • $begingroup$
    Are the +67m/s drag loss related to the attitude change, from horizontal to suborbital trajectory? And are drag gains (from not having to go through 9km of dense atmosphere) already summed up into this result of +67?
    $endgroup$
    – qq jkztd
    Apr 22 at 14:34






  • 1




    $begingroup$
    "Isp underexpansion losses at low altitude" and "improved engine Isp due to altitude start" seem like they should be the same thing, so I'm a little suspicious of this accounting.
    $endgroup$
    – Russell Borogove
    Apr 22 at 14:39










  • $begingroup$
    The book doesn't go into more detail than what I've supplied. The calculation was originally made by BAe and TsAGI for a presentation to ESA.
    $endgroup$
    – Hobbes
    Apr 22 at 15:03










  • $begingroup$
    Could this be the difference? 'Isp underexpansion losses' are the losses you avoid by not running the rocket at 0-9 km altitude, and 'improved engine Isp' is the gain you get by tuning the nozzle for the 9km+ regime.
    $endgroup$
    – Hobbes
    Apr 22 at 15:48










  • $begingroup$
    What's interesting about this is while Elon Musk has said it's only around a 5% savings, this comparison shows substantially more.
    $endgroup$
    – TemporalWolf
    Apr 22 at 20:18











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









7












$begingroup$

I came across a fairly detailed comparison made by the team that worked on Interim HOTOL.



Delta-v required for a vertical launch SSTO (e.g. Delta Clipper) to LEO: 9361 m/s



For Interim Hotol:



  • speed supplied by launch aircraft (An-225), launching at Mach 0.8 at 9 km altitude: - 235 m/s

  • drag loss: + 67 m/s

  • gravity losses: - 670 m/s

  • Isp underexpansion losses at low altitude: - 180 m/s

  • Thrust vectoring demands: + 10 m/s

  • Improved engine Isp due to altitude start: - 214 m/s

for a total reduction in delta-V of 1222 m/s, or 13%, translating into a 24% reduction in propellant requirement.



From the book 'Spaceflight in the era of aero-space planes' (R. Hannigan, Krieger publishing, 1994).






share|improve this answer









$endgroup$












  • $begingroup$
    Are the +67m/s drag loss related to the attitude change, from horizontal to suborbital trajectory? And are drag gains (from not having to go through 9km of dense atmosphere) already summed up into this result of +67?
    $endgroup$
    – qq jkztd
    Apr 22 at 14:34






  • 1




    $begingroup$
    "Isp underexpansion losses at low altitude" and "improved engine Isp due to altitude start" seem like they should be the same thing, so I'm a little suspicious of this accounting.
    $endgroup$
    – Russell Borogove
    Apr 22 at 14:39










  • $begingroup$
    The book doesn't go into more detail than what I've supplied. The calculation was originally made by BAe and TsAGI for a presentation to ESA.
    $endgroup$
    – Hobbes
    Apr 22 at 15:03










  • $begingroup$
    Could this be the difference? 'Isp underexpansion losses' are the losses you avoid by not running the rocket at 0-9 km altitude, and 'improved engine Isp' is the gain you get by tuning the nozzle for the 9km+ regime.
    $endgroup$
    – Hobbes
    Apr 22 at 15:48










  • $begingroup$
    What's interesting about this is while Elon Musk has said it's only around a 5% savings, this comparison shows substantially more.
    $endgroup$
    – TemporalWolf
    Apr 22 at 20:18















7












$begingroup$

I came across a fairly detailed comparison made by the team that worked on Interim HOTOL.



Delta-v required for a vertical launch SSTO (e.g. Delta Clipper) to LEO: 9361 m/s



For Interim Hotol:



  • speed supplied by launch aircraft (An-225), launching at Mach 0.8 at 9 km altitude: - 235 m/s

  • drag loss: + 67 m/s

  • gravity losses: - 670 m/s

  • Isp underexpansion losses at low altitude: - 180 m/s

  • Thrust vectoring demands: + 10 m/s

  • Improved engine Isp due to altitude start: - 214 m/s

for a total reduction in delta-V of 1222 m/s, or 13%, translating into a 24% reduction in propellant requirement.



From the book 'Spaceflight in the era of aero-space planes' (R. Hannigan, Krieger publishing, 1994).






share|improve this answer









$endgroup$












  • $begingroup$
    Are the +67m/s drag loss related to the attitude change, from horizontal to suborbital trajectory? And are drag gains (from not having to go through 9km of dense atmosphere) already summed up into this result of +67?
    $endgroup$
    – qq jkztd
    Apr 22 at 14:34






  • 1




    $begingroup$
    "Isp underexpansion losses at low altitude" and "improved engine Isp due to altitude start" seem like they should be the same thing, so I'm a little suspicious of this accounting.
    $endgroup$
    – Russell Borogove
    Apr 22 at 14:39










  • $begingroup$
    The book doesn't go into more detail than what I've supplied. The calculation was originally made by BAe and TsAGI for a presentation to ESA.
    $endgroup$
    – Hobbes
    Apr 22 at 15:03










  • $begingroup$
    Could this be the difference? 'Isp underexpansion losses' are the losses you avoid by not running the rocket at 0-9 km altitude, and 'improved engine Isp' is the gain you get by tuning the nozzle for the 9km+ regime.
    $endgroup$
    – Hobbes
    Apr 22 at 15:48










  • $begingroup$
    What's interesting about this is while Elon Musk has said it's only around a 5% savings, this comparison shows substantially more.
    $endgroup$
    – TemporalWolf
    Apr 22 at 20:18













7












7








7





$begingroup$

I came across a fairly detailed comparison made by the team that worked on Interim HOTOL.



Delta-v required for a vertical launch SSTO (e.g. Delta Clipper) to LEO: 9361 m/s



For Interim Hotol:



  • speed supplied by launch aircraft (An-225), launching at Mach 0.8 at 9 km altitude: - 235 m/s

  • drag loss: + 67 m/s

  • gravity losses: - 670 m/s

  • Isp underexpansion losses at low altitude: - 180 m/s

  • Thrust vectoring demands: + 10 m/s

  • Improved engine Isp due to altitude start: - 214 m/s

for a total reduction in delta-V of 1222 m/s, or 13%, translating into a 24% reduction in propellant requirement.



From the book 'Spaceflight in the era of aero-space planes' (R. Hannigan, Krieger publishing, 1994).






share|improve this answer









$endgroup$



I came across a fairly detailed comparison made by the team that worked on Interim HOTOL.



Delta-v required for a vertical launch SSTO (e.g. Delta Clipper) to LEO: 9361 m/s



For Interim Hotol:



  • speed supplied by launch aircraft (An-225), launching at Mach 0.8 at 9 km altitude: - 235 m/s

  • drag loss: + 67 m/s

  • gravity losses: - 670 m/s

  • Isp underexpansion losses at low altitude: - 180 m/s

  • Thrust vectoring demands: + 10 m/s

  • Improved engine Isp due to altitude start: - 214 m/s

for a total reduction in delta-V of 1222 m/s, or 13%, translating into a 24% reduction in propellant requirement.



From the book 'Spaceflight in the era of aero-space planes' (R. Hannigan, Krieger publishing, 1994).







share|improve this answer












share|improve this answer



share|improve this answer










answered Apr 22 at 13:26









HobbesHobbes

96.7k2272427




96.7k2272427











  • $begingroup$
    Are the +67m/s drag loss related to the attitude change, from horizontal to suborbital trajectory? And are drag gains (from not having to go through 9km of dense atmosphere) already summed up into this result of +67?
    $endgroup$
    – qq jkztd
    Apr 22 at 14:34






  • 1




    $begingroup$
    "Isp underexpansion losses at low altitude" and "improved engine Isp due to altitude start" seem like they should be the same thing, so I'm a little suspicious of this accounting.
    $endgroup$
    – Russell Borogove
    Apr 22 at 14:39










  • $begingroup$
    The book doesn't go into more detail than what I've supplied. The calculation was originally made by BAe and TsAGI for a presentation to ESA.
    $endgroup$
    – Hobbes
    Apr 22 at 15:03










  • $begingroup$
    Could this be the difference? 'Isp underexpansion losses' are the losses you avoid by not running the rocket at 0-9 km altitude, and 'improved engine Isp' is the gain you get by tuning the nozzle for the 9km+ regime.
    $endgroup$
    – Hobbes
    Apr 22 at 15:48










  • $begingroup$
    What's interesting about this is while Elon Musk has said it's only around a 5% savings, this comparison shows substantially more.
    $endgroup$
    – TemporalWolf
    Apr 22 at 20:18
















  • $begingroup$
    Are the +67m/s drag loss related to the attitude change, from horizontal to suborbital trajectory? And are drag gains (from not having to go through 9km of dense atmosphere) already summed up into this result of +67?
    $endgroup$
    – qq jkztd
    Apr 22 at 14:34






  • 1




    $begingroup$
    "Isp underexpansion losses at low altitude" and "improved engine Isp due to altitude start" seem like they should be the same thing, so I'm a little suspicious of this accounting.
    $endgroup$
    – Russell Borogove
    Apr 22 at 14:39










  • $begingroup$
    The book doesn't go into more detail than what I've supplied. The calculation was originally made by BAe and TsAGI for a presentation to ESA.
    $endgroup$
    – Hobbes
    Apr 22 at 15:03










  • $begingroup$
    Could this be the difference? 'Isp underexpansion losses' are the losses you avoid by not running the rocket at 0-9 km altitude, and 'improved engine Isp' is the gain you get by tuning the nozzle for the 9km+ regime.
    $endgroup$
    – Hobbes
    Apr 22 at 15:48










  • $begingroup$
    What's interesting about this is while Elon Musk has said it's only around a 5% savings, this comparison shows substantially more.
    $endgroup$
    – TemporalWolf
    Apr 22 at 20:18















$begingroup$
Are the +67m/s drag loss related to the attitude change, from horizontal to suborbital trajectory? And are drag gains (from not having to go through 9km of dense atmosphere) already summed up into this result of +67?
$endgroup$
– qq jkztd
Apr 22 at 14:34




$begingroup$
Are the +67m/s drag loss related to the attitude change, from horizontal to suborbital trajectory? And are drag gains (from not having to go through 9km of dense atmosphere) already summed up into this result of +67?
$endgroup$
– qq jkztd
Apr 22 at 14:34




1




1




$begingroup$
"Isp underexpansion losses at low altitude" and "improved engine Isp due to altitude start" seem like they should be the same thing, so I'm a little suspicious of this accounting.
$endgroup$
– Russell Borogove
Apr 22 at 14:39




$begingroup$
"Isp underexpansion losses at low altitude" and "improved engine Isp due to altitude start" seem like they should be the same thing, so I'm a little suspicious of this accounting.
$endgroup$
– Russell Borogove
Apr 22 at 14:39












$begingroup$
The book doesn't go into more detail than what I've supplied. The calculation was originally made by BAe and TsAGI for a presentation to ESA.
$endgroup$
– Hobbes
Apr 22 at 15:03




$begingroup$
The book doesn't go into more detail than what I've supplied. The calculation was originally made by BAe and TsAGI for a presentation to ESA.
$endgroup$
– Hobbes
Apr 22 at 15:03












$begingroup$
Could this be the difference? 'Isp underexpansion losses' are the losses you avoid by not running the rocket at 0-9 km altitude, and 'improved engine Isp' is the gain you get by tuning the nozzle for the 9km+ regime.
$endgroup$
– Hobbes
Apr 22 at 15:48




$begingroup$
Could this be the difference? 'Isp underexpansion losses' are the losses you avoid by not running the rocket at 0-9 km altitude, and 'improved engine Isp' is the gain you get by tuning the nozzle for the 9km+ regime.
$endgroup$
– Hobbes
Apr 22 at 15:48












$begingroup$
What's interesting about this is while Elon Musk has said it's only around a 5% savings, this comparison shows substantially more.
$endgroup$
– TemporalWolf
Apr 22 at 20:18




$begingroup$
What's interesting about this is while Elon Musk has said it's only around a 5% savings, this comparison shows substantially more.
$endgroup$
– TemporalWolf
Apr 22 at 20:18

















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