Ion Thruster Performance Calculator

Calculator Inputs

Use the engineering inputs below to estimate beam-driven thrust, efficiency, total impulse, and mission-level delta-v from an available propellant budget.

Propellant

Choose a preset or use a custom ion mass.

Custom atomic mass (amu)

Used only when custom propellant is selected.

Beam current (A)

Ion beam current supplied by the power system.

Beam voltage (V)

Acceleration voltage that sets ion exhaust energy.

Total propellant flow (mg/s)

Combined ionized and non-ionized flow delivered to the thruster.

Auxiliary power (W)

Includes discharge, heater, keeper, or support loads.

Beam divergence half-angle (deg)

Applied as a cosine thrust correction.

Double-ion current ratio I++/I+

Used to adjust thrust for multiply charged ions.

Mission thrust duration (h)

Used for mission impulse and propellant use.

Initial spacecraft mass (kg)

Starting mass before the planned burn.

Available propellant budget (kg)

Used for ideal burn time and ideal delta-v.

Reset

Example Data Table

This worked example uses xenon with a realistic electric propulsion operating point for quick benchmarking and output verification.

Parameter	Example Input	Example Result
Propellant	Xenon	131.29 amu
Beam current	2.30 A	Ion mass flow 3.1297 mg/s
Beam voltage	1200 V	Ion exhaust velocity 41,997.21 m/s
Total propellant flow	4.40 mg/s	Specific impulse 2,950.99 s
Auxiliary power	380 W	Total input power 3,140.00 W
Beam divergence half-angle	8°	Divergence factor 0.99027
Double-ion ratio	0.08	Double-ion factor 0.97830
Mission duration	1,500 h	Total impulse 687,599.54 N·s
Initial mass / budget	650 kg / 60 kg	Ideal delta-v 2,802.77 m/s
Corrected thrust	—	127.3332 mN

Formula Used

1) Ion exhaust velocity

v_i = √(2eV_b / m_i)

This estimates the ideal ion velocity from the acceleration voltage and ion mass.

2) Ion mass flow from beam current

ṁ_i = I_b m_i / e

Beam current determines how much ionized propellant exits the thruster each second.

3) Thrust correction

F_div = cos(θ) and γ = (1 + 0.707r) / (1 + r)

The calculator applies beam divergence and double-ion corrections before reporting thrust.

4) Corrected thrust

T = F_div γ ṁ_i v_i

This gives the thrust after directional and charge-state penalties are included.

5) Specific impulse

I_sp = T / (ṁ_p g₀)

Effective exhaust performance is based on total propellant flow, not only ionized flow.

6) Jet power and total efficiency

P_jet = T² / (2ṁ_p) and η_T = P_jet / P_in

These values compare useful beam kinetic power against total electrical input.

7) Mission delta-v

Δv = I_sp g₀ ln(m₀ / m_f)

The ideal rocket equation is used with the supplied propellant budget.

How to Use This Calculator

Select a propellant or choose a custom atomic mass.
Enter beam current, beam voltage, and total propellant flow.
Add auxiliary power to represent discharge and support loads.
Enter beam divergence and double-ion ratio for a corrected thrust estimate.
Provide mission duration to estimate total impulse and propellant use.
Enter initial spacecraft mass and available propellant budget for ideal delta-v.
Press Calculate Performance to show results above the form.
Use the CSV or PDF buttons to export the computed result table.

Frequently Asked Questions

1) What does this calculator estimate?

It estimates corrected thrust, specific impulse, exhaust velocity, jet power, electrical efficiency, total efficiency, thrust-to-power ratio, mission impulse, propellant use, burn time, and ideal delta-v.

2) Why is total propellant flow different from ion mass flow?

Total flow includes all propellant entering the thruster. Ion mass flow is the portion inferred from beam current. Their ratio indicates mass utilization and highlights how much propellant becomes accelerated ions.

3) Why does beam divergence reduce thrust?

A divergent plume spreads momentum away from the desired thrust axis. The calculator applies a cosine correction so only the axial momentum contributes to useful thrust.

4) What is the double-ion current ratio?

It represents the fraction of doubly charged ions relative to singly charged ions. Multiply charged ions change the relation between current and momentum, so thrust is corrected with an approximate charge-state factor.

5) Why can efficiency exceed 100% in bad inputs?

That usually signals inconsistent inputs. Examples include unrealistically low total flow, too little auxiliary power, or beam current and voltage values that imply more jet power than the supplied electrical power.

6) Is the delta-v result exact for a mission?

No. It is an ideal rocket-equation estimate using the calculated specific impulse and the entered propellant budget. Real missions also depend on gravity losses, duty cycle, throttling, and power availability.

7) Which propellant should I choose?

Xenon is common because it is dense, inert, and widely used. Krypton can reduce cost and storage mass penalties. Custom mass lets you compare alternative ions during early trade studies.

8) When should I export CSV or PDF?

Export after calculating a case you want to save, compare, or share. CSV works well for spreadsheets and batch studies, while PDF is better for quick reporting and design reviews.