1

Acceleration

[ak-sel-uh-rey-shuhn]

Though commonly used to describe an increase in speed, it is technically a change (increase or decrease) in velocity, which includes not only speed but also direction. For example, if speed remains constant during a change in direction (think race cars on a track), velocity increases, so there is acceleration.

1

Aeronautics

[air-uh-not-iks]

The science (yes, science!) of building and operating vehicles for flight.

1

Aerospace

[air-oh-speys]

Though this term is sometimes used to describe the Earth's atmosphere and the space beyond, it is typically used to describe the science or technology of flight and the industry that develops products and services for flight. The scientists and staff who work to keep the ISS fully functioning in its quest to conduct beneficial research works in the aerospace industry.

1

Applied Science

[uh-plahyd sahy-uhns]

A collection or group of light-sensitive solar cells used to generate electrical power. It is sometimes called a solar array, and the ISS depends on two solar array "wings" that are made up of two "blankets" that can fold up or spread out to make each wing approximately 4,600 square feet.

1

Ascent

[uh-sent]

The flight of a spacecraft from launch to orbit (for example, the flight of a visiting vehicle headed to the ISS).

1

Astronaut

[as-truh-nawt]

A person who is trained to fly in space, whether as a crew member or passenger. In Russia, they are commonly referred to as cosmonauts.

1

Astronautics

[as-truh-naw-tiks]

The science and technology of space flight.

1

Atmosphere

[at-muhs-feer]

The mixture of gases that surround a planet, moon or star. The Earth's atmosphere is divided into five layers: Troposphere (closest to the Earth), Stratosphere, Mesosphere, Thermosphere, and Exosphere where atmosphere mingles with space. The ISS orbits the Earth within its atmosphere.

1

Atomic Oxygen

[uh-tom-ik ok-si-juhn]

The oxygen molecule in its common form on Earth is O2 - the kind we breathe and the kind that is in water that is made up of two oxygen atoms. But atomic oxygen is O1 with a different configuration of electrons and only one atom. What that means is that we can't breathe it, and it's highly reactive to some kind of stimulation on it. Atomic oxygen makes up about 96% of the atmosphere where the ISS orbits the Earth largely because of the ultraviolet radiation that breaks apart O2 molecules.