Dario Pastrone

Politecnico di Torino, DIMEAS, Faculty Member

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Michele Brun

University of Cagliari

K.W. Chau

Hong Kong Polytechnic University

Soon -Guan Tan

UPM - Universiti Putra Malaysia

Professor Bashir O M O L A R A N Bello

University of Abuja, Nigeria

Harijono Djojodihardjo

Institut Teknologi Bandung

Scott Madry

University of North Carolina at Chapel Hill

Daniel Condurache

Technical University of Iasi

Mirabel Rezende

Universidade Federal de São Paulo (UNIFESP)

Jana Javornik

University of East London

Gwen Robbins Schug

University of North Carolina at Greensboro

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Papers by Dario Pastrone

Nozzle Effects on Linear Stability Behaviour of Combustors

Paper ISABE 93-704

Multiphysics modelling for a hybrid rocket engine with liquefying fuel: a sensitivity analysis on combustion instability

AIAA AVIATION 2022 Forum

GTOC5: Results from the Politecnico di Torino and Università di Roma Sapienza

Problems that concern a large number of possible targets, such as those typical of Global Traject... more Problems that concern a large number of possible targets, such as those typical of Global Trajectory Optimization Competitions (GTOC), require a global search for the optimal solution and a local refinement. During the 5th edition of the Global Trajectory Optimization Competition, we used different approximated techniques to perform a global search of suitable asteroid sequences; a local optimization method based on an indirect approach was then used to verify the feasibility of the suggested legs and perform the optimization of multi-leg sequences. All the tools used by our team are presented in this paper. The best solution found is described and discussed.

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Mixture-ratio control to improve LOX/LH2 rocket performance

Paper AIAA 96-310

Traiettorie ottimali di ascesa in orbita

Optimal Aeroassisted GEO-to-LEO Transfer by an Indirect Method

Paper AAS 95-45

Indirect Optimization Method for Round-Trip Mars Trajectories

Paper AAS 95-30

Optimal propellant control in hybrid rocket engines

31st Joint Propulsion Conference and Exhibit, Jul 10, 1995

Paper AIAA 95-239

Optimal three-dimensional trajectories for manned Mars missions

Paper AIAA 96-361

A Parametric Analysis of Hybrid Rocket Motors for Sounding Rockets

Optimization of rocket ascent trajectories using an indirect procedure

Guidance, Navigation, and Control Conference, Aug 7, 1995

An indirect method for optimizing the threedimensional ascent trajectory of a two-stage rocket le... more An indirect method for optimizing the threedimensional ascent trajectory of a two-stage rocket leaving a rotating Earth is presented. The procedure assumes that the trajectory is divided into a succession of arcs by corners, i.e., points where discontinuities of the flight strategy occur. By replacing the time with a new independent variable, the corner positions are fixed: the boundary value problem is simplified and can be solved by means of an efficient procedure based on Newton's method. The optimization method is used in this paper to analyze the finite-thrust ascent to orbit, taking into account the maximum admissible value of the dynamic pressure, which is related to the thermal and mechanical loads that act on the rocket structure. The necessary conditions for optimizing the trajectory and obtaining the maximum payload are derived. Numerical results confirm the efficiency of the proposed method, even when the problem formulation introduces jumps in the state, adjoint and control variables.

Optimization of Hybrid Propellant Mars Ascent Vehicle

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Jul 25, 2014

The use of hybrid rocket engines for ascent from Mars’s surface is analyzed. The engine design an... more The use of hybrid rocket engines for ascent from Mars’s surface is analyzed. The engine design and the ascent trajectory are optimized by means of a nested procedure which employs a direct method to optimize the engine design parameters and an indirect method to optimize the ascent trajectory. Ascent trajectories of a two-stage vehicle for the return of samples from Mars’ surface and for a manned mission are considered as test cases. The same engine is used in both the first stage (a cluster of engines is considered) and for the second stage (a single engine) in order to limit the development costs. Results demonstrate the feasibility of the concept.

Acoustic Analysis of Hybrid Rocket Combustion Chambers

Journal of Propulsion and Power, May 1, 2010

ABSTRACT A method based on passive linear stability measurement has been developed to investigate... more ABSTRACT A method based on passive linear stability measurement has been developed to investigate combustion dynamics in hybrid rocket motors. A one-dimensional model is used to describe the acoustic motions inside the rocket chamber as a function of the motor axial coordinate. The equations of mass, momentum, and energy are solved for the average flow. A linearized analysis, which takes combustion response functions into account, provides pressure and velocity acoustic oscillations. When the boundary conditions at the nozzle inlet are enforced and the response functions are known, the acoustic modes and growth constant can be derived, whereas the coupled responses can be determined from the experimental measurement of the mode frequencies. If noise sources in the control volume are accounted for, then it is theoretically possible to determine the response functions at all frequencies simply by measuring the pressure fluctuations at the head end of the motor. Experimental data are analyzed and contrasted to the proposed one-dimensional model, showing a good agreement.

Design Trade-offs for Hybrid Rocket Motors

ABSTRACT A new method is developed for preliminary design of hybrid rocket motors. A cooperative ... more ABSTRACT A new method is developed for preliminary design of hybrid rocket motors. A cooperative evolutionary method is used with an indirect approach to perform the coupled optimization of hybrid rocket motor and trajectory for a sounding rocket. Different propellant combinations are considered for a sounding rocket application. In addition, the effects of throat erosion are discussed, taking into account recent CFD evaluation of throat regression rate in nozzles of hybrid rocket motors.

Optimal Performance of a Dual-Fuel Single-Stage Rocket

Journal of Spacecraft and Rockets, Sep 1, 1998

ABSTRACT The theory of optimal control is used to maximize the performance of a single-stage rock... more ABSTRACT The theory of optimal control is used to maximize the performance of a single-stage rocket that is powered by liquid oxygen (LOX)/kerosene (RP-1) engines in parallel with LOX/liquid hydrogen engines. For the sake of simplicity and because of the theoretical nature of the work, the rocket motion is analyzed in the absence of gravitational and aerodynamic forces; either the vehicle gross mass or the dry mass is minimized for the required payload and velocity increment. The analysis provides the optimal values of the constant mixture ratios of the engines and the best time for switching off the hydrocarbon engine. The results confirm that the use of a hydrocarbon engine at liftoff is recommended for minimum system dry mass, whereas it is required only for the highest velocity increments in the case of minimum gross mass. The influence of the thrust level and engine mass on the rocket performance is also discussed.

Oxidizer Control and Optimal Design of Hybrid Rockets for Small Satellites

Journal of Propulsion and Power, Mar 1, 2005

ABSTRACT The parameters that affect the design of a hybrid rocket for small satellites are highli... more ABSTRACT The parameters that affect the design of a hybrid rocket for small satellites are highlighted, and the benefit of the oxidizer flow rate control is analyzed. A single-port circular-section polyethylene grain is considered; the oxidizer is 85% hydrogen peroxide. The engine design is optimized to search for the minimum engine mass when the initial satellite mass and the required velocity increment are assigned. First, the simplest blowdown feed system is considered. The analysis shows that the optimal design depends on a lower limit for the regression rate and sometimes on a further constraint, which is related to the occurrence of thermal choking. The initial values of the mixture ratio, the thrust level and the initial port area to the throat area ratio seem to be the most important parameters for an optimal design. As far as the oxidizer flow rate control is concerned, several control strategies, namely, constant mixture ratio, repressurization, constant combustion chamber pressure, and constant propellant tank pressure, are compared to the simplest blowdown system. The constant mixture ratio control is the worst case, as the mass and volume are similar to the blowdown case, while a large thrust variation occurs. Repressurization reduces the thrust variation. Constant pressure controls (both combustion chamber and tank pressures) guarantee a quasi-constant thrust and reduce engine dimensions, with a limited mass penalty.

Simple Strategy for Powered Swingby

Journal of Guidance Control and Dynamics, 1999

ABSTRACT The use of thrust during a close encounter with a celestial body can significantly impro... more ABSTRACT The use of thrust during a close encounter with a celestial body can significantly improve the efficiency of the swingby maneuver, A parametric analysis of a powered swingby with the moon is carried out to find the optimal combined use of a gravity assist and propulsion, A single impulse, usually applied inside the satellite&#39;s sphere of influence, is minimized to achieve an assigned energy with respect to the Earth, for an assigned hyperbolic excess velocity on entering the sphere. Numerical results are presented, but emphasis is placed on the physical reasoning of the suggested strategies that are sometimes different from those found in recent literature, A longer stay on the low-energy, large-deflection hyperbola is always convenient. When geocentric energy is increased, thrust is applied after the passage at the periapsis, with a small misalignment with respect to the spacecraft velocity, to obtain a larger turn angle from the swingby, If reduction of the geocentric energy is required, the selenocentric energy is increased or reduced, depending on the magnitude of the inbound hyperbolic excess velocity, and the corresponding strategies are rather different.

Optimal Low-Thrust Escape Trajectories Using Gravity Assist

Journal of Guidance Control and Dynamics, Sep 1, 1999

ABSTRACT Electric propulsion provides a spacecraft with continuous steering capabilities, which c... more ABSTRACT Electric propulsion provides a spacecraft with continuous steering capabilities, which can be used to approach a planet with hyperbolic excess velocity that enhances the gravity assist. Low-thrust trajectories to escape from the solar system are considered in the present paper, which searches for the strategy that maximizes the spacecraft energy for assigned payload and engine operating time. The optimal conditions to escape using electric propulsion and gravity assist are presented for the cases of free-height and minimum-height flybys. Optimal trajectories that exploit Jupiter or Venus flybys have been computed for constant exhaust power with either constant or variable specific impulse; the procedure is also able to determine the optimal power level and to suggest when it is convenient to switch the engine on and off. The benefit that system performance can receive by increasing the number of controls, i.e., by adding the possibility of coast arcs and engine throttling to the thrust direction control, is also noted.