Artificial Gravity Max Saeger and Kyle Reuscher

What is Artificial Gravity?

• Artificial gravity is defined as the increase or decreased “apparent” gravity acting on an object

• Artificial gravity is extremely important in space travel

• Without artificial gravity astronauts experience Space Adaptation Syndrome

Space Adaptation Syndrome • Without artificial gravity SAS causes bone density decrease,

nausea, balance issues, and fatigue

• SAS is caused by the changes in g-forces. This severely affects a humans spatial orientation.

• “Differences in gravitational forces similar to transition to weightlessness

during a space voyage, impact our spatial orientation and require

adaptation by many of the physiological processes in which our balance

system plays a part. As long as this adaptation is incomplete, this can be

coupled to motion sickness (nausea), visual illusions and disorientation." -

Space Daily

How do we Achieve Artificial Gravity?

• A great solution to SAS is artificial gravity, this is achieved in multiple different ways:

• Two concepts discussed in class:

o Rotationo Linear Acceleration

Other methods:

o Masso Magnetism

Rotational Artificial Gravity

• A spacecraft that is rotating produces a coriolis effect.

• This is the most common form of artificial gravity used in spacecrafts.

• Centrifugal force(discussed in class) pushes away from the axis of rotation producing a feeling of gravity.

• The following slide was taken from John Hopkin’s of Penn State University “Motion in a circle” lecture notes as an example problem of rotationa artificial gravity.

Connection to Class In the movie “2001, a Space Odyssey” astronauts are provided

with an artificial gravity by rotating the spacecraft

If the spacecraft has a radius of 50 m, how fast would it need to rotate to provide “1g” at its’ rim? What is the period of rotation?

If the astronaut walks from the rim to toward the hub, what artificial gravity does she experience halfway to the hub?

-Penn State John Hopkin’s lecture notes

Types of Centrifugal Force

Fictitious Centrifugal

• Exerted by: no real force

• Exerted upon: all bodies (coriolis effect)

• Direction: away from rotational axis

Reactive Centrifugal

• Exerted by: bodies moving in curved path

• Exerted upon: object causing the curved motion

• Direction: opposite of centripetal force

Coriolis Effect

• Defined as the deflection of moving objects when they are viewed through a rotating frame

• This is the formula for magnitude and direction of coriolis acceleration.

• Applications of this formula help provide proper artifical gravity.

Linear Acceleration Artificial Gravity

• Linear Acceleration can produce enough g-force, if moving forward fast enough to force the objects in the opposite direction of the acceleration, causing an artificial gravity.

• This type of artificial gravity is often used in Hall Effect Thrusters and Variable Specific Impulse Magnetoplasma Rocket (VSIMRs).

Relation to Physics Rotation:

• Centrifugal Force: the pull of gravity outward as the objects inside a spacecraft attempt to travel in a straight line due to inertia.

• Centripetal Force: the force required for the objects to travel in a circle.

• In accordance with Newton’s Third Law, the gravity felt by the objects is simply the reaction force of the object on the hull reacting to the centripetal force of the hull on the object.

Relation to Physics

● Kinetic energy: spinning up parts or all of the habitat requires energy. This would require a propulsion system and propellant of some kind to spin up (or spin down) or a motor and counterweight to of some kind to spin in the opposite direction.

● Linear Acceleration: linear acceleration can provide sufficient g-force to provide useful benefits, but can only maintain that speed for several minutes because of a limited supply of fuel. Thus, you need a rocket that provides very high specific impulse but low thrust in order to operate for longer distances.

Alternatives to Artificial Gravity

● Using items of large mass and installing them in aircrafts can force the object to produce it’s own gravitational field and pull everything towards it, though large amounts of mass are needed to create even a small amount of g’s.

● Using objects with a large magnetic field can also create an alternative to gravity, but these magnets are not useful in a productive way.

Calculations

Artificial Gravity (enjoy)

Reference • http://en.wikipedia.org/wiki/Artificial_gravity

• "Why Do Astronauts Suffer From Space Sickness?". ScienceDaily. 2008-05-23.

• http://en.wikipedia.org/wiki/Space_adaptation_syndrome#cite_note-sciencedaily-3

• Hopkins, John. "Motion In a Cicle." Motion In a Circle. State College. 05

Feb. 2014. Lecture.

• http://www.popularmechanics.com/science/space/rockets/why-dont-we-ha

ve-artificial-gravity-15425569

• http://en.wikipedia.org/wiki/Centrifugal_force