Orbital Decay Predictor
Predict orbital lifetime for LEO spacecraft. Models atmospheric drag using ballistic coefficient, solar activity, and altitude-dependent density profiles.
What It Does
The Orbital Decay Predictor estimates how long a spacecraft will remain in orbit before reentering the atmosphere. Input your orbit altitude, spacecraft mass, cross-sectional area, drag coefficient, and solar activity level. The predictor computes the ballistic coefficient and propagates the orbit forward, outputting altitude vs time, estimated reentry date, and compliance with the 25-year deorbit guideline.
Key Features
- Atmospheric density models with solar activity (F10.7) input
- Altitude vs time propagation with reentry date prediction
- 25-year and 5-year compliance check with pass/fail indicator
- Ballistic coefficient sensitivity analysis
Why It Matters
Every LEO spacecraft must demonstrate compliance with orbital debris mitigation guidelines, typically the 25-year deorbit rule (and increasingly the 5-year FCC rule). If your spacecraft cannot deorbit naturally within the required timeframe, you need a propulsive deorbit capability, which adds mass, cost, and complexity. Running this analysis early prevents discovering compliance problems at the FCC licensing stage.
Calculator
da/dt = −2π·ρ·a²·(Cd·A/m), exponential atmosphere
Inputs
Result
What this does not model. An order-of-magnitude estimate, not a reentry prediction. One fixed density with a 50 km scale height, a circular orbit, and no solar-cycle variation, which is the single biggest term: the same spacecraft can differ by years between solar minimum and maximum. Use a propagator with a real atmosphere model for a 25-year compliance case.
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Included in every plan
The aerospace pack ships 127 calculators, and there are 478 across all 20 industry packs. Plans start at $14.99/month.