Space Debris Risk Calculator

Collision probability from object density and orbital altitude.

Orbital altitude (km)

Cross-section area (m²)

Mission duration (years)

Whipple shield (mm)

Can maneuver (1=yes, 0=no)

Tab to move between fields

P(collision >10cm) %

P(collision >1cm) %

0.05

P(catastrophic) %

0.05

P(collision >1mm) %4.62

Annual P(tracked) %0

Expected 1mm+ impacts0.05

Debris density >1cm (/km³)0

How to Use This Calculator

Enter orbital altitude (km), spacecraft cross-section area (m²), and mission duration (years).
Set Whipple shield thickness (mm) and indicate whether the spacecraft can maneuver.
Review probability of collision with tracked objects (>10 cm), centimeter-scale debris, and millimeter debris.
Catastrophic collision probability should be below 0.001 (0.1%) for the mission lifetime.
Maneuverability dramatically reduces risk — even one debris avoidance maneuver per year matters.

How the result changes with Orbital altitude (km)

Orbital altitude (km)	P(collision >1cm) %	P(catastrophic) %
380	0.02	0.02
830	0.25	0.25
1,370	0.09	0.09
1,820	0.03	0.03

Orbital altitude (km): Orbit altitude. Highest debris density at 800-1000 km. ISS at ~408 km is relatively cleaner.
Cross-section area (m²): Effective collision cross-section of the spacecraft. ISS: ~2,500 m². CubeSat 3U: ~0.03 m².
Mission duration (years): Planned mission lifetime. Longer duration = higher cumulative collision probability.
Whipple shield (mm): Micrometeoroid/debris shield thickness. 0 = unshielded. ISS uses multi-layer shields ~10 mm effective.
Can maneuver (1=yes, 0=no): Whether spacecraft can perform collision avoidance maneuvers when warned by tracking networks.

P(collision >10cm) %: Probability of collision with tracked objects (>10 cm, catastrophic).
P(collision >1cm) %: Probability of collision with objects >1 cm (mission-ending).
P(collision >1mm) %: Probability of impact from objects >1 mm (can damage components).
P(catastrophic) %: Combined probability of mission-ending collision.
Annual P(tracked) %: Per-year collision probability with tracked objects.
Expected 1mm+ impacts: Expected number of impacts from objects >1 mm over the mission.
Debris density >1cm (/km³): Spatial density of debris objects >1 cm at this altitude.

Identify Input Parameters
4 parameters
Orbital altitude (km) = 550, Cross-section area (m²) = 20, Mission duration (years) = 5, Whipple shield (mm) = 0 = 5 input(s) provided
Calculate P(collision >10cm) %
P(collision >10cm) % = Number((pCollisionTracked * 100).toPrecision(3))
0.0000473 = 0.0000473
Calculate P(collision >1cm) %
P(collision >1cm) % = Number((pCollision1cm * 100).toPrecision(3))
0.0473 = 0.0473
Calculate P(catastrophic) %
P(catastrophic) % = Number((pCatastrophic * 100).toPrecision(3))
0.0474 = 0.0474
Calculate P(collision >1mm) %
P(collision >1mm) % = Number((pCollision1mm * 100).toPrecision(3))
4.62 = 4.62
Calculate Annual P(tracked) %
Annual P(tracked) % = Number((annualPTracked * 100).toPrecision(3))
0.00000947 = 0.00000947