What is the function of the oxidiser in solid rocket propellant?

Estimating the vehicle's position during flight

Steering the vehicle onto its intended trajectory

Supplying what the fuel needs for combustion

Measuring the pressure of gases after they leave the nozzle

Which activity is an example of telemetry during a missile flight test?

Tracking movement through reflected radar signals

Recording movement through an electro-optical tracking system

Sending onboard system measurements to receiving equipment

Sending control commands from receiving equipment to the vehicle

Pralay: How Guidance and Flight Testing Support a Surface-to-Surface Missile

Why in news?

Pralay, India’s indigenous surface-to-surface quasi-ballistic missile, is in the news after Akashvani reported a successful test from the Integrated Test Range at Chandipur, off the Odisha coast. Developed by the Defence Research and Development Organisation (DRDO), the missile brings together solid-propellant propulsion, guidance and navigation. Flight tests allow developers and users to examine how these systems perform together.

What kind of missile is Pralay?

A surface-to-surface missile is launched from the ground or sea surface to strike a surface target. Pralay can be launched from a mobile launcher. In its December 2021 maiden-flight announcement, the Ministry of Defence gave its range as 150–500 kilometres. This provides an early official description of the system’s reach and launch arrangement.

A trajectory is the path followed during flight. Ballistic motion is shaped mainly by gravity after the powered push, with air resistance also affecting motion through the atmosphere. A quasi-ballistic missile combines this type of flight with the ability to manoeuvre. Its guidance and control systems help it follow an intended path. Pralay’s maiden-flight release reported that the test validated its control, guidance and mission algorithms.

How does solid propellant provide thrust?

In a solid-propellant rocket motor, fuel and an oxidiser are mixed into a solid material. The oxidiser supplies what the fuel needs to burn. Once ignited, the propellant produces hot, high-pressure gases. These gases accelerate through a nozzle, and their movement produces a force on the rocket in the opposite direction. That forward force is called thrust.

Carrying an oxidiser allows a rocket to operate without taking in surrounding air for combustion. Propulsion supplies the push; the flight-control system directs the vehicle’s motion as it travels.

Navigation, guidance and control

Navigation estimates a vehicle’s position and motion. Guidance uses information about the vehicle and its objective to determine the path it should follow. Control turns the required corrections into changes in motion. These functions work together: knowing the present position helps the system identify a correction, and control makes that correction.

The Ministry of Defence describes Pralay as using advanced guidance and navigation for high precision. The underlying engineering task is to bring the actual flight close to the intended flight. Testing provides measurements against which that performance can be assessed.

Four-step diagram links a test flight, radar and optical tracking plus telemetry, recorded data, and comparison with mission objectives. — Clarity original diagram: tracking and telemetry provide complementary measurements for flight evaluation.

How a test range measures a flight

The Integrated Test Range (ITR) provides launch and evaluation facilities for missiles, rockets and other airborne systems. Radar and electro-optical instruments track a vehicle’s movement. Telemetry sends measurements from the flying vehicle to receiving equipment, giving the test team information about its systems during flight.

Engineers combine tracking and telemetry records to reconstruct the trajectory and examine system performance. In a December 2025 Pralay trial, DRDO launched two missiles in quick succession from the same launcher. ITR sensors tracked their flights, while ship-based telemetry equipment recorded the terminal events near the impact points. This earlier trial illustrates how instruments at different locations contribute to a test record.

Conclusion

Pralay’s development links propulsion, navigation, guidance and control with measured flight performance. A test range makes that performance observable through tracking and telemetry. Comparing the recorded flight with the mission objectives is a central step in evaluating a missile system.