Aerospace engineering
Aerospace engineering is the primary branch
of engineering concerned with the research,
design, development, construction, testing,
science and technology of aircraft and spacecraft.
It is divided into two major and overlapping
branches: aeronautical engineering and astronautical
engineering.
Aeronautics deals with aircraft that operate
in Earth's atmosphere, and astronautics deals
with spacecraft that operate outside the Earth's
atmosphere.
Aerospace engineering deals with the design,
construction, and study of the science behind
the forces and physical properties of aircraft,
rockets, flying craft, and spacecraft.
The field also covers their aerodynamic characteristics
and behaviors, airfoil, control surfaces,
lift, drag, and other properties.
Aeronautical engineering was the original
term for the field.
As flight technology advanced to include craft
operating in outer space, the broader term
"aerospace engineering" has largely replaced
it in common usage.
Aerospace engineering, particularly the astronautics
branch, is often referred to colloquially
as "rocket science", such as in popular culture.
Overview
Flight vehicles are subjected to demanding
conditions such as those produced by changes
in atmospheric pressure and temperature, with
structural loads applied upon vehicle components.
Consequently, they are usually the products
of various technological and engineering disciplines
including aerodynamics, propulsion, avionics,
materials science, structural analysis and
manufacturing.
The interaction between these technologies
is known as aerospace engineering.
Because of the number of disciplines involved,
aerospace engineering is carried out by teams
of engineers, each having their own specialised
area of expertise.
The development and manufacturing of a modern
flight vehicle is an extremely complex process
and demands careful balance and compromise
between abilities, design, available technology
and costs.
Aerospace engineers design, test, and supervise
the manufacture of aircraft, spacecraft, and
missiles.
Aerospace engineers develop new technologies
for use in aviation, defense systems, and
space.
History
The origin of aerospace engineering can be
traced back to the aviation pioneers around
the late 19th to early 20th centuries, although
the work of Sir George Cayley dates from the
last decade of the 18th to mid-19th century.
One of the most important people in the history
of aeronautics, Cayley was a pioneer in aeronautical
engineering and is credited as the first person
to separate the forces of lift and drag, which
are in effect on any flight vehicle.
Early knowledge of aeronautical engineering
was largely empirical with some concepts and
skills imported from other branches of engineering.
Scientists understood some key elements of
aerospace engineering, like fluid dynamics,
in the 18th century.
Many years later after the successful flights
by the Wright brothers, the 1910s saw the
development of aeronautical engineering through
the design of World War I military aircraft.
The first definition of aerospace engineering
appeared in February 1958.
The definition considered the Earth's atmosphere
and the outer space as a single realm, thereby
encompassing both aircraft (aero) and spacecraft
(space) under a newly coined word aerospace.
In response to the USSR launching the first
satellite, Sputnik into space on October 4,
1957, U.S. aerospace engineers launched the
first American satellite on January 31, 1958.
The National Aeronautics and Space Administration
was founded in 1958 as a response to the Cold
War.
Elements
Some of the elements of aerospace engineering
are:
Fluid mechanics – the study of fluid flow
around objects.
Specifically aerodynamics concerning the flow
of air over bodies such as wings or through
objects such as wind tunnels (see also lift
and aeronautics).
Astrodynamics – the study of orbital mechanics
including prediction of orbital elements when
given a select few variables.
While few schools in the United States teach
this at the undergraduate level, several have
graduate programs covering this topic (usually
in conjunction with the Physics department
of said college or university).
Statics and Dynamics (engineering mechanics) –
the study of movement, forces, moments in
mechanical systems.
Mathematics – in particular, calculus,
differential equations, and linear algebra.
Electrotechnology – the study of electronics
within engineering.
Propulsion – the energy to move a vehicle
through the air (or in outer space) is provided
by internal combustion engines, jet engines
and turbomachinery, or rockets (see also propeller
and spacecraft propulsion).
A more recent addition to this module is electric
propulsion and ion propulsion.
Control engineering – the study of mathematical
modeling of the dynamic behavior of systems
and designing them, usually using feedback
signals, so that their dynamic behavior is
desirable (stable, without large excursions,
with minimum error).
This applies to the dynamic behavior of aircraft,
spacecraft, propulsion systems, and subsystems
that exist on aerospace vehicles.
Aircraft structures – design of the physical
configuration of the craft to withstand the
forces encountered during flight.
Aerospace engineering aims to keep structures
lightweight.
Materials science – related to structures,
aerospace engineering also studies the materials
of which the aerospace structures are to be
built.
New materials with very specific properties
are invented, or existing ones are modified
to improve their performance.
Solid mechanics – Closely related to material
science is solid mechanics which deals with
stress and strain analysis of the components
of the vehicle.
Nowadays there are several Finite Element
programs such as MSC Patran/Nastran which
aid engineers in the analytical process.
Aeroelasticity – the interaction of aerodynamic
forces and structural flexibility, potentially
causing flutter, divergence, etc.
Avionics – the design and programming of
computer systems on board an aircraft or spacecraft
and the simulation of systems.
Software – the specification, design, development,
test, and implementation of computer software
for aerospace applications, including flight
software, ground control software, test & evaluation
software, etc.
Risk and reliability – the study of risk
and reliability assessment techniques and
the mathematics involved in the quantitative
methods.
Noise control – the study of the mechanics
of sound transfer.
Aeroacoustics – the study of noise generation
via either turbulent fluid motion or aerodynamic
forces interacting with surfaces.
Flight test – designing and executing flight
test programs in order to gather and analyze
performance and handling qualities data in
order to determine if an aircraft meets its
design and performance goals and certification
requirements.
The basis of most of these elements lies in
theoretical physics, such as fluid dynamics
for aerodynamics or the equations of motion
for flight dynamics.
There is also a large empirical component.
Historically, this empirical component was
derived from testing of scale models and prototypes,
either in wind tunnels or in the free atmosphere.
More recently, advances in computing have
enabled the use of computational fluid dynamics
to simulate the behavior of fluid, reducing
time and expense spent on wind-tunnel testing.
Those studying hydrodynamics or Hydroacoustics
often obtained degrees in Aerospace Engineering.
Additionally, aerospace engineering addresses
the integration of all components that constitute
an aerospace vehicle (subsystems including
power, aerospace bearings, communications,
thermal control, life support, etc.) and its
life cycle (design, temperature, pressure,
radiation, velocity, lifetime).
Taught courses
Aerospace engineering may be studied at the
advanced diploma, bachelor's, master's, and
Ph.D. levels in aerospace engineering departments
at many universities, and in mechanical engineering
departments at others.
A few departments offer degrees in space-focused
astronautical engineering.
Some institutions differentiate between aeronautical
and astronautical engineering.
In popular culture
The term "rocket scientist" is sometimes used
to describe a person of great intelligence
since "rocket science" is seen as a practice
requiring great mental ability, especially
technical and mathematical ability.
The term is often used mockingly, such as
in the expression "it's not rocket science"
to indicate that the task is simple.
Strictly speaking, the use of the word "science"
in "rocket science" is a misnomer since science
is about understanding the origins, nature,
and behavior of the universe; engineering
is about using scientific and engineering
principles to solve problems and develop new
technology.
However, the media and the public often incorrectly
use "science" and "engineering" as synonyms.
