1. Gemini Launch Vehicle (GLV): The Gemini spacecraft was launched into orbit using the GLV, a modified Titan II intercontinental ballistic missile (ICBM).

2. Injection into Orbit: The GLV propelled the Gemini spacecraft into an elliptical orbit around Earth, with an initial apogee (highest point) of approximately 160 miles (260 kilometers) and a perigee (lowest point) of about 100 miles (160 kilometers).

Spacecraft Structure and Design:

1. Reentry Module: The Gemini spacecraft consisted of two main modules: the reentry module and the adapter module. The reentry module housed the astronauts and was designed to withstand the intense heat and pressure during reentry into Earth's atmosphere.

2. Adapter Module: The adapter module connected the reentry module to the launch vehicle and provided additional space for equipment, such as fuel cells, batteries, and scientific instruments.

3. Retro-Rockets: Attached to the adapter module were retro-rockets, which were used to slow down the spacecraft for reentry and enable a controlled descent.

Life Support Systems:

1. Environmental Control System: The Gemini spacecraft was equipped with an environmental control system that regulated temperature, humidity, and pressure inside the cabin to ensure a comfortable environment for the astronauts.

2. Oxygen and Water Supply: The spacecraft carried oxygen and water supplies for the astronauts, with backup systems in case of emergencies.

3. Waste Management: The spacecraft also included waste management systems to collect and dispose of human waste.

Orbital Operations:

1. Rendezvous and Docking: A significant achievement of the Gemini program was the ability to rendezvous (meet up) with another spacecraft in orbit and dock with it. This was crucial for future missions, such as the Apollo moon landing, which required the joining of the command module and the lunar module in orbit.

2. Extravehicular Activities (EVAs): Gemini astronauts performed EVAs, also known as spacewalks, to conduct experiments, retrieve experiments from satellites, and perform tasks outside the spacecraft.

Reentry and Landing:

1. Deorbit Maneuver: To begin the reentry process, the spacecraft fired its retro-rockets to reduce its velocity and initiate descent.

2. Atmospheric Reentry: The spacecraft reentered Earth's atmosphere at a high speed, causing intense heating. The reentry module's heat shield protected the astronauts from the extreme temperatures.

3. Parachute Deployment: As the spacecraft slowed down, parachutes were deployed to further reduce its speed and enable a safe landing.

4. Splashdown: The Gemini spacecraft landed in the ocean, where recovery forces would retrieve the astronauts and the spacecraft.

The Gemini program paved the way for the Apollo missions and demonstrated the advancements necessary for human space exploration. It also set important records, including the longest human spaceflight at the time and the first spacewalk by an American astronaut.