As sirens blare and Israeli air defenses intercept incoming threats in the dead of night, a pattern has emerged in Iran’s missile strategy: darkness. Repeated missile barrages launched from Iran during the overnight hours are no coincidence—they reflect a deliberate military and technological doctrine designed to obscure, surprise, and instill fear.

While nighttime offers obvious concealment, the choice to strike under the cover of darkness is rooted in far more than visibility. It is a combination of technical constraints, operational necessity, and psychological warfare.

Missiles, unlike aircraft, cannot rely on atmospheric oxygen for propulsion. Instead, they must carry both fuel and oxidizer—components necessary for combustion—within their systems. This is because ballistic missiles reach altitudes where oxygen is sparse or nonexistent.

This fundamental requirement divides missiles into two categories: those powered by liquid fuel and those using solid fuel—each with its strategic implications.

Liquid fuel: Powerful but exposed

Iran's long-range missiles, including the Shahab series, typically use liquid fuel. These missiles require a complex fueling process before launch, involving two separate tanks—one for fuel and one for oxidizer. The operation is time-sensitive, hazardous, and requires stationary launch infrastructure and ground crews.
Missiles launched from Iran are intercepted as seen from Ashkelon, June 15, 2025 (credit: REUTERS/Amir Cohen )
Missiles launched from Iran are intercepted as seen from Ashkelon, June 15, 2025 (credit: REUTERS/Amir Cohen )
This makes the fueling stage the missile’s most vulnerable window, especially under the watchful eye of enemy satellites and surveillance aircraft.

To reduce the risk of detection and attack, Iran often conducts fueling operations at night, when visibility is low and the chances of aerial detection drop significantly.

Solid fuel: Mobile and ready

In contrast, short- and medium-range missiles such as the Fateh-110 and Zolfaghar are typically powered by solid fuel. These systems are pre-loaded with a mix of fuel and oxidizer in a solid form, stored within the missile’s body. They are launch-ready, do not require on-site fueling, and can be fired from mobile platforms, making them ideal for surprise strikes and decentralized warfare.

However, once ignited, solid-fuel missiles cannot be shut down or throttled. The launch is irreversible—an operational trade-off for mobility and speed.

Why missiles must carry their own oxygen

The question of why missiles need onboard oxidizers often arises. Unlike jet engines, which intake oxygen from the atmosphere, missile engines must operate in environments where oxygen is insufficient or entirely absent.

Ballistic missiles can ascend dozens—or even hundreds—of kilometers into the sky, well beyond breathable altitudes. To ensure sustained propulsion, they must carry everything needed for combustion from the outset.

Doctrine shaped by technology and tactics

Iran’s repeated use of nighttime launches is no random decision. It reflects a multi-layered military doctrine that accounts for technical realities, strategic opportunities, and the psychological dynamics of war.

By leveraging both solid and liquid-fueled missiles, mobile launch platforms, and the natural concealment of night, Iran has built a system that prioritizes survivability, surprise, and psychological impact—even when the missiles themselves fail to reach their targets.

In the ongoing battle for deterrence and defense, the timing of the launch is as critical as the missile itself.