Meteoroid and debris models and tools in SPENVIS

H. Ludwig

D. HeynderickxBIRA, Ringlaan 3, B-1180 Brussel, Belgium

Radiation environment models

• Implementation of MAGNETOCOSMICS (Geant4)• Implementation of radiation belt models

• POLE GEO electron model• SAMPEX/PET dynamic LEO proton model• Jovian radiation belts

• Implementation of solar energetic proton models• MSU model (Nymmik)• ESP model for solar minimum (PSYCHIC)• Extend the energy range of the JPL model below 5MeV and

above 100MeV

• Upgrade of the orbit generator• implement new trajectory types: hyperbolic, parabolic,

interplanetary, escape• modify other models and tools that use the orbit generator• introduce flags for coordinate systems

Meteoroids and Orbital Debris

• Meteoroids originate from the asteroid belts and orbit around the Sun

• Space debris originate from break-ups of satellites and rocket upper stages

• Statistical meteoroid and debris flux models focus on particles with diameters between approximately 0.1m and 1cm

• Typical impact velocities:• Debris: 10km/s • Meteoroids: 20km/s

Damage Caused by Hypervelocity Impacts on Spacecraft

• Damage increases with particle size:• 0.1m – 10m: Degradation of spacecraft

surfaces and sensitive equipment (mirrors, optical sensors, …)

• 50m - 500m: Penetration of outer spacecraft coatings, foils, solar cells

• > 1mm: Penetration of exposed tanks, serious damage to impacted spacecraft component

• > 1cm: Complete destruction of impacted spacecraft component

from G. Drolshagen, Hypervelocity impact effects on spacecraft, 2001

Meteoroids and Orbital Debris in Space

Impact flux of particles on a randomly tumbling plate in LEO

• MASTER2001 debris model• Divine-Staubach meteoroid model

Impactor diameter [m]Impactor diameter [m]

Cum

ulat

ive

flux

[1

/m2

/yr]

Impact Risk Assessment

• Calculate the number of impacting particles (impact flux) using meteoroid and space debris flux models

• Use a suitable particle-wall interaction model to discriminate penetrating from non-penetrating particles

• Combine the flux model with the particle-wall interaction model to obtain the number of penetrating particles per unit area and time (failure flux)

Particle-Wall Interaction Models(“Damage Equations”)

• Empirical damage law defining the threshold particle diameter dp

th for penetrating a wall of thickness t at velocity v and angle

• Derived from test shot data• Crater and hole size

equations• Single wall ballistic limit

equation for maximum target thickness that can be penetrated:

)cos(v

td thp

Obtaining the number of penetrations

• For each impact velocity and angle, calculate the corresponding threshold particle diameter dp

th(v,)

• Calculate the impact flux for an environment in which the smallest particle diameter is dp

th(v,)

• Take the average of this flux over all impact velocities and angles according to the proper velocity and angular distribution

SPENVIS M/OD Calculation Tool(under development)

• Calculates the impact and failure fluxes to a plate on orbit

• Plate may have arbitrary orientation (fixed with respect to flight direction, sun-pointing, …) or may instead be randomly tumbling

• Flux models:• Already included: NASA90 (debris), Grün (meteoroids)• Planned: MASTER 200x (debris), Divine-Staubach

(meteoroids)• Damage equations:

• Single wall and double wall ballistic limit equations• Crater size equations

• Calculation of cratered area, as well as average impact velocity and average impact angle

• To become available in December 2005