Collision

In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word collision refers to incidents in which two or more objects collide with great force, the scientific use of the term implies nothing about the magnitude of the force.

In the aerospace context, collision refers to a crash or impact event involving two or more aircraft, spacecraft, or other objects in the airspace or space. Collisions can occur as a result of human error, mechanical failure, or other factors, and can result in significant damage to the aircraft or spacecraft involved, as well as injury or death to the occupants or crew.

Examples of collisions in aerospace context:

• In 2002, a mid-air collision occurred between a chartered plane and a helicopter over the Amazon rainforest in Brazil, resulting in the deaths of all 14 people on board the two aircraft.
• In 1956, two fighter jets collided during a training exercise in the United States, resulting in the deaths of both pilots.
• In 1997, the Mars Climate Orbiter, a NASA spacecraft, was destroyed when it entered the Martian atmosphere at the wrong angle due to a collision with another spacecraft or asteroid.
• In 2007, the Chinese ASAT (Anti-Satellite) missile test resulted in the collision between China's Fengyun-1C weather satellite and the inactive Russian Cosmos-2251 satellite.

Collisions in space can also happen between spacecraft and space debris, which is becoming a concern as the amount of debris in orbit is increasing. This can cause damage to the spacecraft, and in severe cases, can cause the mission to be lost. To avoid collisions with space debris, spacecraft operators use radar and other technologies to track and avoid debris in orbit.