The Soviet Union launched Sputnik 1, the first artificial satellite, into orbit in 1957.

A rocket engine's primary function is to generate thrust by expelling high-velocity gases, propelling the rocket forward.

Nuclear rocket engines are still in the experimental stage and are not yet used in operational rockets.

A rocket's payload can carry astronauts, scientific instruments, satellites, or other objects into space.

Apogee is the highest point in a rocket's trajectory.

The Saturn V rocket was used to launch the Apollo 11 mission, which carried the first humans to the moon.

Re-entry is the process of a rocket or spacecraft returning to Earth's atmosphere.

The Falcon 9 rocket, developed by SpaceX, is known for its reusable first stage, which can land vertically after launch.

The Saturn V rocket, used in the Apollo program, is the largest rocket ever built.

The Hubble Space Telescope was launched into orbit by the Space Shuttle Discovery in 1990.

Insertion is the process of a rocket achieving orbit around a celestial body.

Mariner 4 was the first spacecraft to successfully fly by Mars and return images of the planet.

Shenzhou 5 was the first Chinese spacecraft to carry a human into space.

The Delta II rocket has been used to launch numerous satellites for the Global Positioning System (GPS).

Staging is the process of a rocket separating its stages during flight to reduce weight and improve efficiency.