NASA rocket scientists often perform feasibility studies which examine a spacecraft design based on the laws of science (physics, mechanics, chemistry, etc.). Scientists, also, use spacecraft design conventions known as "rules of thumb" to determine whether a spacecraft concept has merit. A basic engineering education includes an introductory course in college physics. The same material is covered in less depth in high school physics as well as grade school science. A student can learn much about the laws of science by attempting an informal feasibility study on a spacecraft from a science fiction comic book, a sci-fi magazine cover, or a STAR WARS or STAR TREK video. Listed below are some of the laws of science often violated by artists and authors. Included are descriptive examples of errors often revealed by such feasibility studies.
One of the best ways of determining what is scientifically reasonable is to imagine yourself inside the subject vehicle. Next, try to compare the vehicle to driving a car, piloting an airplane, or even riding a bicycle. These vehicles must obey the laws of science. Each requires a means of steering, an engine or motor for transporting the vehicle, and a way of positioning the driver or passengers in order for them to control and ride inside the vehicle. When something does not seem correct about the science fiction art, try to classify which of the items below may be violated by the drawing.
For example, some artists fail to draw a viewing window for the pilot of a spacecraft to see where the craft is going. Others, leave out a hatch for the astronaut to enter or leave the vehicle. Can you imagine a car without doors? Below is a list of some of the most obvious abuses of the laws of science in science fiction art.
NEWTON'S THIRD LAW: Every action requires an equal and opposite reaction. This is Newton's third law. It is taught in science in elementary school. It is one of the scientific laws often found inconsistent with sci-fi artwork. Showing a spacecraft doing a space maneuver without steering thrusters is an example of violating this law of science. Having two opposing spacemen boxing in space as though on Earth is another example of its abuse. The first time a punch landed, the fighters would separate so dramatically that the fight would end.
EINSTEIN'S THEORY OF RELATIVITY: The fastest speed possible is the speed of light which is approximately 186,000 miles per second. This is a part of Einstein's theory. In certain conditions, it can be considered as a law of science. Einstein's equation states that the mass of an object times the speed of light squared equals the energy contained within an object. Einstein's equation demonstrates that when an object approaches the speed of light its mass increases toward infinity. The speed of light is a limiting speed of starships. Einstein's theory also deals with time. According to Einstein, as a starship's speed approaches the speed of light, the passage of time slows with respect to the launch site where the mission began. Those on board the starship grow older more slowly than those remaining on the home planet. Authors writing about trips to the stars often violate Einstein's theory when they speak of faster than light propulsion, warp drive, alternate universes, and other means of placing the setting of their story at light year distances from Earth.
CENTRIPETAL FORCE: Centripetal force is the force that causes a mass to travel in an arc or circular orbit. It is equal to the object's mass times its tangential velocity squared divided by the radius of the arc or circular path. The "pulling away of the mass from the radius of curvature of the arc (the orbit)" is due to the inertia of the object causing it to try to move in a straight line. The pulling away is a result of Newton's First Law. (Newton's First Law: An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.)
THE LAW OF UNIVERSAL GRAVITATION: Every particle of matter in the universe attracts every other particle with a force proportional to the product of the masses of the particles and inversely proportional to the square of the distance between them. Newton's law of universal gravitation is often ignored in sci-fi art. To show a hovering flying saucer, suspended above a planet's surface without visible rocketry, rotating propellers or helicopter rotors is a violation of Newton's law of gravitation.
THE GAS LAW: The gas law is PV = nRT where P is the pressure of a gas on the walls of a closed container and V is the volume of the container. The constants, n and R, relate P and V to the temperature of the gas, T. Showing astronauts in the vacuum of space without pressure suits violates the gas law. Space station crew quarters must be pressurized. Exit from space vehicles requires airlocks to preserve air pressure within pressurized compartments. Opening a pressurized compartment to the vacuum of space without an airlock rapidly releases precious oxygen. Drawing such activity as a nominal procedure causing no detrimental results on the crew is a violation of the gas law.