Over the past two decades there have been a number of proposals suggesting that air launching a satellite is an effective and low-cost approach to space operations. Launchspace has followed each of these ideas and has discounted all of these.

Yes, Orbital's Pegasus is a successful launch vehicle that is launched from an aircraft. But, it is not a low-cost launcher. The simple fact is that there are no low-cost air-launched schemes that work.

The latest proposal is from a new Swiss-based company, Swiss Space Systems (S3). A recent announcement states that this company will provide low-cost satellite launches. In fact, the claim indicates the cost could be a mere one-quarter of current market rates.

More specifically, S3 stated its goal was to offer launches for under $11 million each. The suggested approach is to use an unmanned suborbital space plane that could carry a satellite with a mass of up to 250 kg.

The company is led by Swiss astronaut Claude Nicollier, who said S3 has a budget of $238 million and plans to begin test launches in by 2017. Nicollier has apparently secured cooperative agreements with ESA and other elements of the aerospace industry to assist in resolving technical matters.

The launch sequence is somewhat complicated. For example, the proposed suborbital space plane would itself be ferried to an altitude of about 33,000 feet by a zero-gravity-capable Airbus A300.

The space plane would use its own rocket to climb to 262,500 feet. At that point the satellite would be released and the space plane would glide back to an earth-based spaceport.

Some of the key details of the ascent operation were not revealed. One of these is the technique for placing the satellite in orbit. Does the space plane inject the satellite into its final orbit, or does the satellite provide its own rocket stage to raise its altitude and speed to establish an orbit?

We suspect the answer is the latter option, because the required technology to accelerate a reusable space plane through the needed speed regime associated with orbital speed does on exist. Therefore, the satellite will have to carry its own boost stage.

To summarize, it looks like we have a complex launch system. An airplane will act as a first stage. Then a space plane will act as a second stage. Finally, a third stage will boost the satellite into its final orbit.

Keep in mind that reusable space planes are expensive to build and operate. The Airbus is expensive to operate. Expendable upper stages are also expensive. We must conclude that a significant reduction in launch costs will be difficult to achieve.