What is rocket science?

• One of the earliest devices that used rocket propulsion was called the aeolipile, designed in the 1st century AD by Heron of Alexandria, and used steam to spin a metal ball.
• Early prototypes of rockets were produced for firework displays in China in the 13th century, with the real, metal versions coming in the 19th century, used in Navy ships as an upgraded version of cannon.
• Early rockets use flammable substances like gunpowder that propel it using the thrust of exhaust gases.

• Inspired by the German V-2 rocket weapon in World War II, many new rocket models were made by Russia and the U.S., as military technology was sought after in the arms race that followed.
• Many American rockets were initially intercontinental ballistic missiles.
• Liquified hydrogen is the preferred substance in modern rockets and those which have to work without air use oxidizers to help with the required oxygen in the system.
• Some newer rockets are electric and use charged ions as thrusters by creating an electric field.

Many rockets have multiple ‘shell’s that fall off during escape velocity and is due to the empty fuel containers that are discarded to save on mass, after their fuel has been utilized.

Landing back on earth is trickier than landing on surfaces with no atmosphere or less gravity, and rockets use air resistance, wings and parachutes to slow down the reentry fall.