Hohmann Transfer Calculator
Calculate fuel-efficient orbital transfer trajectories using Hohmann transfer orbit mechanics
Orbital Transfer Parameters
Primary Body Characteristics
Orbit Parameters
Altitude from surface of primary body
Altitude from surface of primary body
Rocket Engine Parameters (Optional)
Hohmann Transfer Results
Transfer Orbit Properties
Delta-V Requirements
Transfer Time (Time of Flight)
Propellant Requirements
Calculation Method: Hohmann transfer orbit using two-body problem assumptions
Assumptions: Circular initial and final orbits, coplanar orbits, impulsive thrust
Orbital Velocities (km/s)
Example: Earth to Mars Transfer
Mission Parameters
Primary Body: Sun (M = 1.989×10³⁰ kg, R = 696,340 km)
Earth Orbit: 146.4 million km altitude from Sun's surface
Mars Orbit: 206.0 million km altitude from Sun's surface
Spacecraft: 200,000 kg initial mass, Isp = 400s
Results
Total Δv Required: ~2.94 km/s
Transfer Time: ~8.6 months
Propellant Mass: ~139,105 kg (69.6% of initial mass)
Transfer Orbit: Elliptical with eccentricity ~0.205
Hohmann Transfer Steps
First Burn
Apply Δv₁ at initial orbit
Increases velocity to enter transfer ellipse
Coast Phase
Travel along transfer orbit
Half orbit duration (transfer time)
Second Burn
Apply Δv₂ at final orbit
Circularizes orbit at destination
Key Formulas
Transfer Orbit Semi-major Axis
Orbital Velocity
Transfer Time
Rocket Equation
Transfer Tips
Hohmann transfer is most fuel-efficient for circular orbits
Requires precise timing for planetary transfers
Transfer time increases with orbital distance ratio
Only valid for coplanar circular orbits
Understanding Hohmann Transfer Orbits
What is a Hohmann Transfer?
A Hohmann transfer is an orbital maneuver that transfers a spacecraft between two circular orbits using the minimum possible delta-v (change in velocity). It consists of two engine burns and a coasting phase along an elliptical transfer orbit.
Why Use Hohmann Transfers?
- •Minimum fuel consumption for orbit changes
- •Well-understood and reliable maneuver
- •Foundation for interplanetary mission planning
- •Optimal for satellite orbit raising/lowering
Physics and Limitations
Assumptions
- • Circular initial and final orbits
- • Coplanar orbits (same orbital plane)
- • Impulsive thrust (instantaneous burns)
- • Two-body problem (no perturbations)
Real-World Considerations
- • Planetary orbital eccentricity
- • Gravitational perturbations
- • Launch windows and timing
- • Finite burn time effects
Note: Real missions often use modified Hohmann transfers or bi-elliptic transfers for better efficiency or mission constraints.