PhD Program

PhD Student Status
Checklist for PhD Degree
Grade Point Average
AE 590 Seminars
Teaching Assistantships
Qualifying Examination
Core Topics
Course Requirements
Joint Programs
Doctoral Committee
Preliminary Examination
Progress of Research
The Final Examination
Degree Conferral
Time Limitations

PhD Student Status

Graduate students admitted to the PhD program with an MS from another institution, or to the PhD Direct program, automatically have PhD student status. 

Graduate students with an MS degree (thesis or non-thesis) from the University of Illinois at Urbana-Champaign must satisfy three requirements to be admitted to the PhD program and enrolled as a PhD student:

  1. a minimum graduate school GPA of 3.5,
  2. approval by their MS advisor (or the AE Director of Graduate Programs for a non-thesis degree),
  3. approval by their prospective PhD advisor

A Direct PhD program is available for highly qualified students who have earned a B.S. degree and intend to pursue the PhD.


The formal requirements for the doctoral degree consist of a minimum of 64 hours beyond the MS degree. The doctoral program, consisting primarily of research, generally includes three stages:

  •  the completion of the MS degree or its equivalent and successful passing of the Departmental PhD Qualifying Examination (completion of these two requirements elevates a student’s status to that of a PhD Candidate);
  •  the completion of a minimum of 32 additional hours of course work and any special course requirements and successful passing of the Preliminary Examination; and
  •  research with a minimum of 32 hours of thesis credit, preparation of a dissertation, and successful passing of the Final Examination.

The three stages can be completed in a minimum of three years of full-time study.  The academic program for each doctoral candidate is planned on an individual basis.


Checklist for PhD degree.

Grade Point Average

All graduate students must maintain a cumulative grade point average (GPA) of at least 3.0 to continue in the AE Graduate Program. The cumulative GPA is computed on all courses taken for credit except thesis and seminar courses in which DFR (deferred), S (satisfactory), and U (unsatisfactory) grades are recorded. 

AE 590 Seminars

All graduate students must register in the seminar course AE 590 and must attend all seminars each semester while they are on campus. 

Teaching Assistantships

In addition, each PhD student must serve as a departmental teaching assistant for one semester. This requirement can be met at any time during the student’s graduate studies in the department. International students for whom English is a second language must first pass an English Proficiency Requirement before serving as a departmental teaching assistant.

Qualifying Examination

Graduate students who seek admission to PhD Candidacy must take the Qualifying Examination by the second offering after two semesters of study after their enrollment as a PhD student, but students may also take the exam as an MS student. The Qualifying Examination (QE) shall be a 3 hour, written, closed-book examination given in January and May and limited to the student's primary discipline (PD). The PDs are:

  • Aerodynamics, Fluid Mechanics, Combustion and Propulsion (AFMCP)
  • Astrodynamics, Control and Dynamical Systems (ACDS)
  • Structural Mechanics and Materials (SMM)

Three months prior to the exam, the student candidate will select a PD, and present to the Head the name of the PhD advisor(s) and a list of graduate courses taken. The Head shall assign the student a Test Number, and forward the list of graduate courses to the chair of the PD Examination Committee.

Primary Discipline Examination Committee. 

The PD Examination Committees are appointed by the Head and shall include the AE tenured or tenure-track faculty in the PD. Emeritus faculty, faculty affiliates and faculty from outside the department may serve; however the committee must have a majority of AE tenure or tenure-track faculty. At least two months prior to the exam, the Committee will provide the student candidate with a list of core topics in the PD on which questions will be based. In addition, a file of previous QE questions is available for reading in the departmental office. The PD Examination Committee shall conduct the QE and evaluate the student's performance and ability to complete the PhD degree. Students who fail the exam for the first time will be allowed a retest in the same PD at the next available opportunity.


Scoring will be conducted "blind," referring to the Test Number. After scoring the exam, and before recommending a result, the student's identity will be revealed to the Committee, and the student's PhD advisor(s) will be consulted. The committee will then evaluate the student's exam performance, summarized by a letter from the committee chair, written with the knowledge of the committee and signed by the chair and members, to the Head. If the student is found deficient in an area, the committee has the flexibility to recommend corrective measures, e.g. taking the exam for a second time or the taking of another course, and will so state in the letter. The Head will be responsible for the final results and for communicating these to the student, the advisor, and the Graduate College. If the QE is not passed on the second try, the student will be dropped from the PhD program. If objections are raised to the results of a QE, the Head may call a special meeting of the faculty, or may ask the AE Graduate Policy Committee to make recommendations to the Head on issues relating to the QE. If a member of the GPC has a conflict of interest the Head will appoint a suitable replacement.


Core Topics

Core topics for each PD are given below.  These core topics can be adjusted for each candidate based on the courses submitted for the qualifying exam.

Aerodynamics and Propulsion

  1. Incompressible Flow:
    • Governing equations
    • Potential flow
    • Airfoil Theory
    • Finite wings
    • Viscous flow
  2. Compressible Flow:
    • Conservation of mass momentum and energy of a fluid
    • Isentropic flow
    • One-dimensional compressible flow
    • Oblique and normal shock waves
    • Prandtl-Meyer expansions
    • Shock-expansion method and method of weak waves
    • Quasi-one-dimensional flow
    • Unsteady waves
  3. Propulsion:
    • Conservation of mass, momentum and energy, thrust equations
    • Chemical rocket performance
    • Combustion chemistry and nozzle flow of a reacting gas
    • Ram-, turbo-, and fan-jets:  ideal cycles and efficiency
    • Subsonic and supersonic inlets
    • Component analysis of compressors, turbines, combustors, and nozzles
    • Off-design behavior
    • Throughflow theory -- the Euler turbine equation

Sample Texts:

  1.    Foundations of Aerodynamics, Bases of Aerodynamic Design, (4th edition, 1986) by A. M. Kuethe and C. Chow, John Wiley and Sons
  2.    Modern Compressible Flow: With Historical Perspective, (2nd edition, 1990) by J. D. Anderson, McGraw-Hill Publishing Company
  3.    Aerothermodynamics of Gas Turbine and Rocket Propulsion, (1988) by G. C. Oates, AIAA

 Dynamics and Control 

  1. Dynamics:
    • Particle kinematics and dynamics in translating and rotating coordinate frames
    • Newton’s second law: translational and rotational applications, mechanical work, kinetic and potential energy
    • Lagrange’s equations for finite-degree-of-freedom mechanical systems
    • Multiple-degree-of-freedom vibration theory
    • Rigid body kinematics and dynamics
  2. Control:
    • Modeling of linear dynamic systems
    • Convolution and block diagram algebra
    • Laplace transform solution of differential equations
    • Linear systems stability: Routh's criterion
    • Performance specification of controlled systems
    • Feedback control of linear systems:  design using different types of feedback
    • Root locus analysis and design
    • Frequency response analysis and design

Sample Texts:

  1. Principles of Dynamics, (2nd edition, 1988) by D. T. Greenwood, Prentice Hall
  2. Feedback Control of Dynamic Systems, (4th edition, 1994) by G. F. Franklin, J. D. Powell, and A. Emami-Naeini, Addison-Wesley

Structures and Materials

  • Analysis of stress and strain
  • Constitution of isotropic and orthotropic materials
  • Properties of common aerospace materials
  • Euler-Bernoulli beams in extension and bending
  • Torsion of shafts
  • Analysis of open and closed section monocoque and semi-monocoque beams and shafts
  • Energy methods, including theorems of virtual work, minimum potential and complementary energy, and Castigliano's Theorem
  • Theory of elastic stability with application to beam-columns
  • Finite element methods applied to truss and frame type structures

Sample Texts:

  1. Introduction to Linear Elasticity, (1994) by Phillip L. Gould, Springer Verlag
  2. Analysis of Aircraft Structures, An Introduction, (1993) by Bruce K. Donaldson, McGraw-Hill

Course Requirements

Because of the wide range of interests in the field of Aerospace Engineering, there are no specific course requirements for the PhD, except a mathematics requirement. Each student plans a program in consultation with his or her thesis advisor. Courses offered by departments other than the AE Department may be included in the area of study when these courses are of particular value to the research work that the student desires to emphasize. This is a list of recommended courses for each area of specialization.

Minimum Course Requirements

  • 32 hours of credit beyond the MS degree.
  • 24 hours beyond the bachelor's degree must be at the 500-level; 16 of these 24 hours must be in Aerospace Engineering.
  • 8 of the 32 hours may be a special project class, defined as an individual or group project, in contrast to a lecture-discussion course with written homework and examinations (AE597).

Mathematics Requirements 

  • PhD candidates are expected to exhibit competence in applied mathematics. They may meet this requirement by taking a minimum of 4 hours of mathematics courses (beyond the MS) from a list of approved Mathematics, Physics, and Theoretical and Applied Mechanics courses. 
  • At least 4 of the 8 required mathematics hours taken for the MS and PhD degrees must be from a 500-level course.

Graduate Options and Joint Programs

AE graduate students have the option of combining their AE degrees with joint programs offered through Computational Science and Engineering, the MBA Program, and the Medical Scholars Program.

Doctoral Committee

During the final stages of the required course work, the candidate consults with the PhD thesis advisor regarding the proposed membership of the candidate's doctoral committee. There must be at least four members on the doctoral committee and the membership must satisfy the following criteria:

  • at least two members must be tenured faculty in the university
  • at least one member must have a primary appointment in a department other than AE
  • at least two members must be from the AE Department
  • the chair of the doctoral committee must have graduate standing and an appointment in the AE Department
  • at least three of members on the committee must be members of the graduate faculty

Once an appropriate membership list has been prepared, the candidate requests each member to serve on the proposed doctoral committee. This committee must be approved by the AE department head and the Graduate College. The candidate in conjunction with the advisor makes arrangements for a suitable time and place for the Preliminary Examination.


All PhD degree candidates must complete Checklists with their advisors to plan their programs.

Preliminary Examination

The Preliminary Examination for the PhD degree is an oral examination administered by the candidate's doctoral committee.

  • The first stage of the PhD degree program must have been completed, which consists of completion of the MS degree and passing the Qualifying Examination, before the Preliminary Examination can be taken. 
  • The Preliminary examination must be taken between nine months and five years before the Final Examination. 
  • Also, the examination may be taken no earlier than the semester in which the candidate completes the 32nd hour of coursework required in the second stage of the PhD program. 
  • The candidate must submit the thesis proposal to the doctoral committee at least two weeks prior to the Preliminary Examination. The proposal must outline the problem to be studied for the PhD degree, the procedures and methods to be used in attacking the problem, work already completed on the chosen problem, and the additional work proposed to be completed.The proposal also must include a tentative title for the thesis.

The Preliminary Examination is intended to test the validity of the thesis proposal and the candidate's fitness to carry out the research work proposed. Typically, it begins with a short presentation by the candidate, outlining the problem chosen, the procedures and methods to be used, the work already completed, and the additional work proposed to be completed for the PhD degree. The committee then questions the candidate regarding the problem, the preliminary results, and the proposed work. The candidate may be asked to clarify matters in the thesis proposal and to defend various aspects of the work already completed or the work being proposed. The committee may suggest alternative methods of attacking the problem or suggest different aspects of the problem as suitable areas for exploration. The committee also may ask questions of a more general nature in order to test the adequacy of the candidate's preparation for the proposed research.

At the conclusion of the examination, the committee deliberates privately, and the chairperson of the committee informs the candidate of one of four possible decisions:

  • The candidate passed the Preliminary Examination and may proceed to independent study and research for the doctoral degree.
  • The examination is temporarily adjourned, and the candidate must revise the thesis proposal and be examined again within six months.
  • The candidate failed, but may submit a new thesis proposal and take another Preliminary Examination after completing additional coursework, independent study, or research;
  • The candidate failed and will not be admitted to another examination. 

Progress of Research

Successful completion of graduate coursework and passing the Preliminary Examination mark the beginning of the third stage of the PhD program.  During this stage, the candidate carries out the research program proposed in the dissertation proposal and writes a doctoral dissertation requiring a minimum of thirty-two hours of credit in AE 599.

If the membership of the doctoral committee is modified for any reason, the modified committee membership must also satisfy the requirements stated above. Modifications should be approved by the head of the department.

The doctoral committee (at least the AE members of the committee) shall meet at least once per year to monitor the progress of the student.  At this meeting the committee will review a written progress report (minimum two pages) submitted by the student.  Any suggestions or deficiencies noted will be communicated to the student.

The Final Examination

During the final stages of the dissertation research when the dissertation is nearing completion, the candidate makes arrangements for a suitable time and place for the Final Examination which is also administered by the candidate's doctoral committee. The candidate must submit the proposed committee list and information about the time and place for the examination to the AE Department Office at least two weeks prior to the date chosen for the Final Examination.  At the same time, the candidate submits the dissertation to the members of the doctoral committee and deposits a copy in the department office for review by all faculty members.

The Final Examination for the PhD degree is a public oral examination administered by the candidate's doctoral committee.  It must take place at least nine months (but no later than five years) after the Preliminary Examination.  The examination is composed of two distinct parts:

  1. the PhD candidate presents a formal one-hour departmental seminar (including some time for questions from the audience) during which the student summarizes the results of his or her research efforts.  Since the presentation is aimed at a fairly general audience, this first part of the defense should focus on the motivations, importance, methodology, and main results of the research work, leaving the more advanced concepts and technical details for the second part of the Final Examination. 
  2. This part, which is also public, consists of a less formal session during which the candidate may be asked to clarify matters in the thesis and to defend various aspects of the work. Errors and ambiguities in the thesis may be brought to the candidate's attention by the members of the thesis committee.  If needed, the student may choose to give an additional presentation on topics not covered, or covered superficially, in the first part of the examination.  This second part of the Final Examination takes place immediately after the general seminar, or at a later date agreed upon by the doctoral committee. 

At the conclusion of both parts of the Final Examination the committee deliberates privately, and the chairperson of the committee informs the candidate of one of five possible decisions:

  1. The candidate passed the Final Examination and the thesis is accepted as submitted; the thesis certificate of approval is signed by all the members of the committee.
  2. The candidate passed the Final Examination but the thesis will be accepted and signed by the committee after various specified corrections and revisions have been made; the candidate must make the necessary changes and submit the thesis to the committee members for their signatures;
  3. The examination is temporarily adjourned, and the candidate must revise the thesis and be examined again within the next six months;
  4. The candidate failed, but may rewrite the thesis and take another Final Examination after completing additional independent study and research;
  5. The candidate failed and will not be admitted to another examination.

Degree Conferral

MS and PhD degrees are conferred in May, August, and January. In order to receive a degree, the student's name must be on the graduation list for the appropriate graduation date. Students should submit their names to the AE Departmental Office at the beginning of the semester in which they intend to deposit their thesis.

The Department of Aerospace Engineering does not have a separate commencement ceremony. Students graduating with a degree from the AE Dept. attend the College of Engineering and/or University of Illinois commencement ceremonies.

Time Limitations

The three stages of the PhD program can be completed in a minimum of three years of full-time study.  A doctoral candidate must complete all requirements, including the MS degree, within seven years of first registering in the Graduate College.  A candidate for the doctoral degree who has received an MS degree elsewhere, however, must complete the requirements within six years of first registration in the doctoral degree program on this campus.  However, the department expects doctoral candidates to complete all the requirements within four years of first registration in the doctoral degree program on this campus.

If more than five years elapse between a student's preliminary and final examinations, the student will be required to demonstrate that his or her knowledge is current by passing a second preliminary examination, which is a prerequisite for admission to the final examination.  If more than one year elapses between the student's final examination, and the deposit of the dissertation in the Graduate College, the dissertation must be accompanied by a statement of explanation from the department head to the Dean of the Graduate College and must be submitted to the Graduate College.



Program Administration:

lambrosatillinois [dot] edu (Prof. John Lambros)
Associate Head, Graduate Programs

tankatillinois [dot] edu (Staci Tankersley)
Program Coordinator, Graduate Programs

Hours: 8:30 AM - 5:00 PM

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