Air Launch Advantages

Below are some of the Advantages of Air Launch. For a really small rocket trying to get into space, air launch can make the difference between making it and not.

Interesting Air Launch Links

Air Resistance for Small Rockets

Air resistance is much more of a problem for a small ground launched rocket than a large one. The total energy of the rocket is determined by the amount of fuel, which goes up with the volume of the rocket, or the cube of the dimensions. The air-resistance is going up with the cross-sectional area, which goes up with the square.

Rockets in Vacuum

The ISP for a rocket is usually rated at sea-level and in a vacuum. If the ISP is 300 at sea-level it might be 350 in a vacuum. Launching at 60,000 feet is much closer to a vacuum than sea-level, so the rocket is more efficient.

If you can design the rocket to operate in low pressure/vacuum and not sea level, then you don't have to compromise the design so much.

Better Failure Modes

A rocket taking off from a launch pad will probably fall back and explode if the engines fail during lift off. An air launched liquid fueled rocket should be able to dump fuel and land if the engines fail. This is called "intact abort" and is a very good thing, since the rocket and any cargo can live to fly again.


By starting out high the rocket can aim more horizontally. Since orbit depends mostly on horizontal velocity, this is efficient. If you start from the ground you are better off to go mostly vertical at first to get out of the air faster.

Potential Energy

Starting from higher up gives you the potential energy of that height before you even start the rocket. This is a smaller effect than the above 2, but every bit helps.

Lower/Shorter Aerodynamic Loads

Starting out at 60,000 feet you have less aerodynamic pressure and less heating.

You can also get rid of a payload shroud earlier. Getting rid of mass saves your rocket energy for the other mass.

Lower Acoustic loads

In a ground launch acoustic energy is reflected from the ground back to the vehicle, but this doesn't occur in an air launch. The thinner air of an air launch also reduce acoustic loads.


An air launched vehicle can avoid turbulance during the rockets flight, so can be designed a bit lighter. You can also avoid lightning.

Red Tape

An air-launch is going to have less red tape to deal with than a rocket using a government launch site. The only private launch site so far is Sea-Launch.
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Copyright (c) 2002, 2003 by Vincent Cate. All rights reserved.