Why Rockets Opt for Low Altitude Launches Instead of High Ones

The question often arises, why don’t rockets use launch facilities that are at higher altitudes to get into orbit? While launches from higher altitudes, like Denver, might save a significant amount of fuel, such as the 5280 feet worth mentioned, there are several reasons why most rocket launches occur at lower altitudes, typically near sea level.

Advantages of Higher Altitude Launches

At higher altitudes, the atmosphere is thinner, which reduces air resistance during the initial phase of flight. This can lead to fuel savings as the rocket ascends. Additionally, launching from a higher altitude can slightly reduce the effects of gravity during the early stages of launch, further contributing to potential fuel efficiency gains.

Thinner Atmosphere: Thinner air means less drag, which can be advantageous for fuel consumption.

Reduced Gravity Losses: Lower gravity near the surface can help rockets maintain speed more efficiently.

Disadvantages of Higher Altitude Launches

Despite these advantages, there are significant disadvantages that make higher altitude launches less practical:

Launch Infrastructure

The majority of existing launch facilities and infrastructure are concentrated at lower altitudes, often near coastlines. This allows for safe over-water trajectories during launch. Building and maintaining infrastructure at high altitudes, such as the Atacama Desert in Chile, would be immensely costly and logistically challenging.

Weather Conditions

Weather patterns at higher altitudes can be unpredictable and harsh. Comparatively, locations with stable, favorable weather conditions are preferred for launches. Launching from a site with consistent and favorable weather can greatly reduce the risk of delays and cancellations.

Orbital Mechanics

Rockets typically need to achieve a specific trajectory and velocity to reach orbit. Launching from a higher altitude may require adjustments to the launch trajectory, which could complicate the necessary path to achieve a precise orbit. Lower altitudes can provide simpler and more direct trajectories.

Access to Desired Orbits

Many satellites are placed in specific orbits that require precise launch angles and trajectories. Launch sites at lower latitudes can facilitate access to a wider range of orbits, particularly geostationary orbits. High-altitude launches may not provide the necessary precision and control to insert satellites into these orbits effectively.

Conclusion

While launching from higher altitudes like Denver could save some fuel due to reduced atmospheric drag, the logistical, technical, and operational challenges generally outweigh the benefits. Therefore, most rockets are launched from established sites closer to sea level, where infrastructure and support systems are already in place. This infrastructure has developed over decades and offers a more reliable and efficient launch process.

In conclusion, while the concept of launching from higher altitudes offers some theoretical advantages, the practical realities of rocket launch operations make low-altitude launch sites the preferred choice for most missions.