Orbital Lifetime Calculator

Orbital decay time from altitude and ballistic coefficient.

Orbital altitude (km)

Spacecraft mass (kg)

Cross-section area (m²)

Drag coefficient

Solar activity (0-2)

Tab to move between fields

Orbital lifetime (days)

1,560,000,000

Orbital lifetime (years)

4,280,000

Ballistic coefficient (kg/m²)18.18

Atmospheric density (kg/m³)0

Orbital period (min)92.41

Decay rate (km/day)0

Complies with 25-yr ruleNo

Orbital Radius6,771,000

Decay Rate Ms0%

How to Use This Calculator

Enter orbital altitude (km), spacecraft mass (kg), and projected cross-section area (m²).
Set the drag coefficient (typically 2.0–2.5 for most spacecraft shapes).
Select solar activity level (low, moderate, or high) — solar maximum significantly increases drag.
Review ballistic coefficient (kg/m²), atmospheric density, orbital period, and lifetime in days and years.
For debris mitigation compliance, orbital lifetime must be below 25 years for LEO objects.

How the result changes with Orbital altitude (km)

Orbital altitude (km): Circular orbit altitude. Below ~300 km decays within weeks. Above ~800 km lasts decades.
Spacecraft mass (kg): Total spacecraft mass including fuel. Heavier = slower decay.
Cross-section area (m²): Average drag cross-sectional area perpendicular to velocity vector.
Drag coefficient: Aerodynamic drag coefficient. Typical satellite: 2.0-2.4. Flat plate: 2.2.
Solar activity (0-2): 0 = solar minimum (low density), 1 = average, 2 = solar maximum (expanded atmosphere, fastest decay).

Ballistic coefficient (kg/m²): m/(Cd×A). Higher = more resistant to drag.
Atmospheric density (kg/m³): Estimated atmospheric density at the orbit altitude.
Orbital period (min): Time for one complete orbit.
Orbital lifetime (days): Estimated time until re-entry due to atmospheric drag.
Orbital lifetime (years): Same lifetime expressed in years.
Decay rate (km/day): Approximate rate of altitude loss per day.
Complies with 25-yr rule: Whether orbital lifetime is under 25 years (IADC debris mitigation guideline).

Identify Input Parameters
4 parameters
Orbital altitude (km) = 400, Spacecraft mass (kg) = 400, Cross-section area (m²) = 10, Drag coefficient = 2.2 = 5 input(s) provided
Calculate Orbital lifetime
1560000000 = 1560000000
Calculate Orbital lifetime
4280000 = 4280000
Calculate Ballistic coefficient
Ballistic coefficient = massKg / (dragCoeff * crossSectionM2)
18.18 = 18.18
Calculate Atmospheric density
Atmospheric density = Number(effectiveDensity.toExponential(3))
9.12e-13 = 9.12e-13