What is Project Gemini?

From November 1961 to November 1966, the United States implemented the "Gemini Constellation" program. Its main task is to research and develop the technology of manned landing on the moon and the ability to train astronauts for long-term flight and extravehicular activities. The plan lasted for 5 years, and completed 10 manned orbits around the earth, each with 2 people, and cost a total of nearly 1.3 billion US dollars. The official announcement of the voyage on December 7, 1961 was the United States' second manned space program. At that time, the "Apollo" manned moon landing plan was being implemented as a transition from "Mercury" to "Apollo".

The purpose of the entire "Gemini" program is to provide flight experiments for the "Apollo" manned moon landing program on the basis of the "Mercury" program and prepare various technical conditions. The main task is to study the long-term space flight of humans under weightless conditions Problems, as well as the development of orbital maneuvering, rendezvous and docking technologies, and the ability of astronauts to perform extravehicular activities.

The main goals of the Gemini program include:

1. Dedicated to show the long-term navigation capabilities of humans and equipment, and prepare for future moon landings or into deeper space;

2. Make effective orbit rendezvous and docking with other orbiting spacecraft, and use the orbiting spacecraft propulsion system to operate the combined spacecraft;

3. Improve spacecraft re-entry and landing methods;

4. Obtain further information on astronauts in weightless environments and record their physiological responses during long flight ^[3]

The Hercules 2 rocket debuted in 1962. As the second-generation intercontinental ballistic missile rocket of the United States Air Force, it uses self-igniting fuel as its power.

Left: Launch vehicles for all Gemini GT-1 to GT-12 launch vehicles.

Long storage time, short preparation time, few parts, simple design. The only drawback is that the propellant combination (nitrogen tetroxide and hydrazine) is extremely toxic compared to propellants such as liquid oxygen.

The reasons why NASA chose the Hercules 2 rocket as the carrier of the Gemini spacecraft are:

1) Hercules 2 was the rocket with the largest carrying capacity in the United States at the time, and only it had the ability to launch the "Gemini" spacecraft;

2) Hercules 2 uses storable propellant, which is easy to handle and handle, and has the characteristics of long-term parking and launch at any time, suitable for manned flight and space rendezvous and docking tasks. ^[8]