Delta-V Budget Tool

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Delta-V Budget

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Delta-V Budget Theory & Notes

Definition

Delta-V (Δv) is the change in velocity required for a spacecraft to perform a maneuver or reach a destination. It represents the total velocity change needed throughout a mission and is a key metric for mission planning and spacecraft design.

Mathematical Foundation

Tsiolkovsky Rocket Equation: Δv = vₑ × ln(m₀/m₁)

Where:

vₑ = Effective exhaust velocity (m/s)

m₀ = Initial mass (wet mass)

m₁ = Final mass (dry mass)

ln = Natural logarithm

Total Mission Δv: Δv_total = Σ(Δv_i) for all mission phases

Mission Phase Categories

Launch: Earth surface to orbit (typically 7,500-9,500 m/s)

Transfer: Orbit-to-orbit maneuvers (varies widely)

Orbital: In-orbit maneuvers, station keeping, plane changes

Landing: Descent and landing maneuvers

Other: Attitude control, rendezvous, emergency maneuvers

Common Delta-V Values

Launch to LEO: ~9,400 m/s (Earth surface to 200km orbit)
LEO to GTO: ~2,400 m/s (Low Earth to Geostationary Transfer Orbit)
GTO to GEO: ~1,500 m/s (Transfer to Geostationary Orbit)
LEO to Moon: ~3,200 m/s (Earth orbit to lunar orbit)
Moon Landing: ~1,800 m/s (Lunar orbit to surface)
LEO to Mars: ~3,600 m/s (Earth orbit to Mars transfer)
Mars Landing: ~2,000 m/s (Mars orbit to surface)
Station Keeping: ~50 m/s/year (GEO satellite maintenance)

Budget Planning Principles

Conservative Margins: Add 10-30% margin for uncertainties
Phase Prioritization: Critical phases get higher margins
Propellant Reserves: Maintain emergency reserves
System Limitations: Consider propulsion system capabilities
Mission Flexibility: Allow for trajectory optimization

Complexity Assessment

< 2,000 m/s: Low complexity (simple missions)

2,000-5,000 m/s: Moderate complexity

5,000-10,000 m/s: High complexity

10,000-20,000 m/s: Very high complexity

> 20,000 m/s: Extreme complexity

Design Implications

Propellant Mass: Higher Δv requires more propellant
Propulsion Systems: May require multiple engine types
Mission Architecture: Influences staging and design
Cost and Risk: Higher complexity increases both
Technology Requirements: May need advanced propulsion

Optimization Strategies

Gravity Assists: Use planetary flybys to reduce Δv
Aerobraking: Use atmospheric drag for orbit insertion
Electric Propulsion: High Isp for long-duration burns
In-Situ Resources: Refuel at destination
Trajectory Optimization: Minimize total mission Δv

Historical Context

Delta-v budgeting became essential with the space age, starting with early satellite missions. The Apollo program demonstrated the importance of careful Δv planning for complex multi-phase missions. Modern missions like Mars rovers and deep space probes rely heavily on accurate Δv budgets for mission success.

Open Source & Transparent

This tool is open source and the underlying logic is fully transparent. You can view the source code, understand the calculations, and even contribute improvements to make it better for everyone.

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