Glossary

alignment: a spacecraft’s position in relation to other objects in space

altitude: the height of an object above a given planet or moon

attitude: a spacecraft’s orientation in space

burn: a short firing of a rocket engine to change a spacecraft’s course or flight path

carbon dioxide: a colorless gas exhaled during breathing. Too much carbon dioxide in a confined area will cause someone to get sick.

command module: the cone-shaped Apollo 13 spacecraft called Odyssey. It contained the crew compartment, instrument panels, and heat shield.

fuel cell: a device in the service module that mixed oxygen and hydrogen to make electricity and water

gravity: the force that pulls everything toward a large object such as a planet or moon

hatch: a doorway in a spacecraft

heat shield: the part of a spacecraft that protects the rest of the craft from the heat of reentering Earth’s atmosphere

jettison: to release

lithium hydroxide canisters: air scrubbers that remove carbon dioxide from the spacecraft and purify the air

lunar module: the spider-shaped Apollo 13 spacecraft called Aquarius. It was the only part of the spacecraft designed to land on the moon. The Apollo 13 crew used it as a lifeboat on their trip back to Earth.

midcourse correction: burning a spacecraft’s engine on the way to or from the moon to place it on the correct flight path

mission control: NASA flight controllers who monitor and manage spaceflights

orbit: to travel in an ellipse around a planet or moon

oxygen: a gas that humans breathe

passive thermal control roll: a maneuver to slowly roll a spacecraft so it doesn’t get too hot on the part facing the sun or too cold on the part facing away from the sun

recovery ship: a ship sent to where a manned spacecraft is expected to land

reentry: to come back into Earth’s atmosphere from space

service module: attached to the command module, the part of the spacecraft that looks like a giant tin can. It contains oxygen, water, heat, and electrical power for the spacecraft.

simulator: a machine astronauts use on the ground at NASA to train for piloting spacecraft

thruster: a small engine used to adjust the position or flight path of a spacecraft

trajectory: the path of an object moving through space