Primary Flight Safety Models

DebRA. Debris Risk Assessment (DebRA) is an APT developed model for flight safety analysts that assesses the risks of RLV (Reusable Launch Vehicle) failure modes … more

Impact. A debris prediction program originally developed by the Aerospace Corporation to model the characteristics of debris resulting from kinetic energy intercepts or explosive breakups. Impact predicts the quantity, size/mass, induced velocity and drag characteristics of debris fragments resulting from user input scenarios. The program distributes fragments/velocities to assure conservation of mass and momentum. This program is widely used to predict collision effects.

MILS. Multiple Impact Location Simulator (MILS) is a fast-running trajectory simulation which uses a fourth order Runge-Kutta integration algorithm to propagate debris fragments resulting from either collision or flight termination. The program applies delta velocity isotropically around the original state vector or reads delta velocity for individual fragments from an IMPACT output file. Wind effects are incorporated into the forces modeled at each integration step. The resolution of the wind input file is user specified. This tool has been used by safety personnel to analyze test scenarios for the GBI, Arrow, and NMD programs.

STK. Satellite Toolkit (STK) is a COTS satellite analysis model that addresses all phases of a satellite’s life-cycle from policy development and design to launch and maintenance operations. STK Communications software provides a Windows interface and allows the analyst to compute a detailed link margin quickly and accurately.

DASP. Debris Analysis for Satellite Programs (DASP) is an APT modification to the Jet Propulsion Laboratory’s Artificial Satellite Analysis Program (ASAP) for high accuracy prediction of orbital flight paths. DASP predicts the orbital characteristics of debris clouds generated by on-orbit breakups and kinetic energy intercepts. DASP applies velocity and drag changes (specified by the user) to the original orbital parameters and propagates the debris cloud using an eighth order Runge-Kutta algorithm and a 40×40 gravity field to integrate the equation of motion. This tool has been used to evaluate debris from exo-intercepts.

TVIP. Turning Vehicle Impact Predictor (TVIP) calculates malfunction turns in any direction based on current state vector, velocity profile, and maximum lateral acceleration capability. This program propagates trajectories to impact from points along the computed turn. It determines worst-case turns and defines hazard areas as part of planning test scenarios. This model has been used to support Arrow test planning.

Ascent. Ascent is a tool developed by Autometric that provides powerful trajectory modeling, end condition targeting, and optimization capabilities. Extensive functionality and graphical user interface allows the user to directly model the vehicle, optimize the trajectory, and transfer the resulting maps, charts, and summary statements into presentation charts or documents.

LiMAns. Link Margin Analysis (LiMAns) is a link margin analysis tool that incorporates the basic gains and losses to determine the link margin from a ground station to any space point or vice versa.

Ground Risk Model (GRM). GRM simulates worst case trim turns from a nominal trajectory followed by flight termination. Modeled turns are based on the Range Safety Officer response time and maximum vehicle capability. Debris fragments are propagated to impact or aircraft altitudes and hazard footprints are developed for each time increment. Casualty expectation is computed for each population center/asset within the hazard area and total mission risks from malfunctions are determined.

BREEZE. Computes concentrations and risks from toxic clouds including weather effects.

AFTOX. Gaussian dispersion model that computes toxic corridors from accidental releases of non-dense gases, evaporating liquids and buoyant plumes.

APT Internal Launch Area Risk Models

TRIAL – Aurora. Trajectories for Risk Investigations At Launch. Simulates launch area 3σ trajectory, tumble turn, straight-up, and 45° trajectories.

FRAG – Aurora. Solid Rocket Motor Fragmentation. Computes breakup model of solid propellant and exterior casing following destruct action for large rocket motors.

FAIL – Aurora & Horizons. Vehicle Failure Filter. Estimates overall and conditional launch vehicle failure probabilities from launch history data.

PADPOP – Aurora. Pad Populations. Converts normal work-day or night population data into launch-specific population data.

RAFIP – Aurora & Horizons. Random-Attitude Failure Impact Points. Calculates the geographic distribution envelope of impacts yielding impact distributions resulting from random-attitude type failures.

SHAPE5. Shaping Constants for Mode 5 Impact Distribution.

DAMP – Aurora. Facility Damage and Personnel Injury. Estimates hit probabilities and casualty expectations considering vehicle performance, sheltering and explosives effects.

DISP – Aurora & Horizons. Impact Locations and Dispersions for DAMP. Propagator that addresses effects of gravity, lateral performance, imparted velocity, drag, lift and winds.

Contour – Aurora. Generate Equi-valued Contour Lines. Generates probability contours for hit probability or casualty expectation.

GenDeb. Generates Debris Classes for Liquid-Propellant. Generates representative debris classes for liquid-propellant launch vehicles.

APT Internal Overflight Risk Models

CORAL – Horizons. Collective Overflight Risk Analysis Tool. Supports lower fidelity overflight risk analyses involving ascent and overflight of launch vehicles.

CORIDORE GIS – Horizons. Corridor Risk Estimation. Computes high fidelity impact probabilities and casualty expectancies for landmass overflight and reentry. Risk computations are visually overlaid on map coverage.

RAPIEC – Horizons. Random-Attitude PI and EC. Estimates exposed populations, land-impact probabilities, and casualty expectations from impact distributions.

TRAX – Horizons. Trajectories for Risk Analysis Extended. Simulates overflight 3σ turn data from nominal trajectory and estimates tumble turn end state vectors.

GreenN. Computations of Green Numbers. Computes minimum thrusting time for a vehicle to move from a normal state to one where endangerment of protected areas is theoretically possible.

AC-HIT. Aircraft Hazards from Impact. Estimates risk to aircraft due to inert debris.

HITP. Estimates risk to ships due to inert debris.

PIRAT – Aurora & Horizons. Propellant Impact Response Assessment Team. Estimates explosive yield for impacting Class 1.3 solid propellant based on Lawrence Livermore National Laboratory (LLNL) calibrated 3D hydrocode.

INCCA. Interactive Coordinate Calculator.

3rd Party Overflight Risk Models

POST. Program To Optimize Simulated Trajectories. Generates high-fidelity 3 or 6‑DOF launch ascent and orbit reentry trajectories for space vehicles.

ALES3D. Arbitrary Lagrange/Eulerian Hydrodynamics Code. Finite element 3D hydrocode developed by LLNL used to model explosion dynamics.

TAOS. Trajectory Analysis and Optimization Software

APT Point of Contact

Bob Baker 256.327.3373