Is Ground-to-Space Pneumatic-Tube Transport Possible?

The idea of using a pneumatic tube to transport objects from the ground to space might seem like a fascinating concept from a science fiction novel. The core idea is to suck out the air and let the pressure differential push the capsule up through the tube. However, prevailing scientific principles and engineering challenges render this idea practically unfeasible.

Concept Overview

The simplest version of the pneumatic tube transport system would involve creating a tube extending from the ground to space. The air pressure on the ground would drive the capsule upward, analogous to drinking through a straw. However, due to the engineering complexities involved in maintaining the structural integrity of the tube, this idea is far from practical.

Limited Reach with Vacuum Pumps

If we were to make the entire tube a vacuum, the air pressure below the capsule would still be too low to reach the desired altitude. This is similar to drinking water through a straw and the maximum height is limited to about 34 feet. By allowing air to be sucked up the tube, the process becomes more efficient due to the lower density of air. However, even under these conditions, the capsule would not be able to achieve the necessary altitude to reach space.

Increasing Altitude and Pressure Challenges

Another approach would involve using increasing air pressure as the capsule ascends. This method would require the volume of the tube to expand as the capsule rises, necessitating the continuous application of more air pressure. However, this approach would demand significant additional infrastructure to support this dynamic pressure adjustment, making it impractical and resource-intensive.

No Viable Solution Without Advanced Technologies

A more feasible method might involve a system that seals off the section of the tube behind the capsule and applies air pressure at the new location. However, the challenges remain - the tube would still require a significant amount of air and infrastructure to maintain the pressure required for ascent, and the energy required would be substantial, far more than using a traditional rocket. Moreover, the entire system would need to ensure air-tightness along its entire length to function efficiently.

Alternative Concepts: Superconducting Magnets and Evacuated Tubes

While the pneumatic tube concept is intriguing, it is not an effective way to reach space. In reality, most schemes for ground-to-space transport involve more advanced technologies, such as superconducting magnets and evacuated tubes. For example, the concept of a bespoke space elevator or a conducting-magnetically levitated train (Maglev) through an evacuated tube can provide the necessary support and reduce air resistance. These methods focus on the use of superconducting magnets to levitate and move the vehicle vertically with minimal air resistance, making the journey more efficient and feasible.

Energy and Infrastructure Requirements

The amount of air required to push a vehicle through a tube into space is vast and would consume more energy than it would save. The limitations of air-tight seals and the infrastructural requirements to support such a system make it unattainable with current technology. Traditional rocket propulsion remains the more viable and established method for reaching space.

Conclusion

The practical limitations of pneumatic tube transport from the ground to space make this concept less viable. Instead, focusing on innovative technologies such as superconducting magnets and evacuated tubes can provide the necessary support and reduce air resistance, making the process more efficient and feasible. Until we develop the necessary infrastructure and technology, traditional rocket propulsion remains the dominant method for reaching space.