1. What is Specific Impulse?

Definition: Specific impulse (I_sp) is a measure of how efficiently a rocket engine uses propellant to produce thrust.

Purpose: It helps aerospace engineers compare the performance of different propulsion systems and propellants.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( I_{sp} \) — Specific impulse (seconds)
• \( F_{thrust} \) — Thrust force (Newtons)
• \( \dot{m} \) — Mass flow rate (kg/s)
• \( g \) — Standard gravity (9.81 m/s²)

Explanation: The thrust force is divided by the product of mass flow rate and standard gravity to determine how long the engine can produce thrust from a given amount of propellant.

3. Importance of Specific Impulse

Details: Higher specific impulse means more efficient propulsion, allowing for longer missions or heavier payloads with the same amount of propellant.

4. Using the Calculator

Tips: Enter the thrust force in Newtons, mass flow rate in kg/s, and gravity (default 9.81 m/s²). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What are typical specific impulse values?
A: Chemical rockets: 200-450s, Ion thrusters: 2000-5000s, Nuclear thermal: 800-1000s.

Q2: Why use standard gravity in the calculation?
A: It provides a consistent reference point for comparing different propulsion systems.

Q3: How does specific impulse relate to fuel efficiency?
A: Higher I_sp means more thrust per unit of propellant, making the engine more fuel-efficient.

Q4: Can specific impulse be improved?
A: Yes, through better propellants, higher combustion temperatures, or more efficient nozzle designs.

Q5: What's the difference between effective and specific impulse?
A: Effective I_sp accounts for atmospheric pressure effects, while specific impulse is measured in vacuum conditions.