What is the second generation manned spacecraft series in the United States?

Gemini series spacecraft are the second generation manned spacecraft in the United States. Gemini series spacecraft have carried out 12 flight tests, including 2 unmanned flights and 10 manned flights. The cost of Gemini project is 1.2834 million dollars, of which the cost of spacecraft is 797.4 million dollars, accounting for 62% of the total cost; $409.8 million for launch vehicles, accounting for 31.93% of the total cost; The supporting facilities amounted to $76.2 million (including $56 million for transforming global communication equipment), accounting for 5.94% of the total cost. "Gemini" program is mainly to provide flight experience and prepare various technical conditions for Apollo manned moon landing program.

In a sense, the shape of Gemini spacecraft is similar to that of Mercury spacecraft. They are basically conical-bell-shaped, with a total length of 5.7 meters, a maximum diameter of 3 meters at the bottom and a weight of 3.0-3.9 tons.

There are two astronauts in the return capsule of Gemini spacecraft, with a total length of 3.4 meters, a maximum diameter of 2.3 meters and an astronaut activity space of 2.55 cubic meters. The total weight is 1982 kg, including the weight of two astronauts 144 kg, and the seat weight is 426 kg. Pure oxygen is used in the cabin with a pressure of 340 MPa.

The equipment cabin length is 1.4m, the maximum diameter is 3.05m, and the weight is 1278kg, in which the weight of the environmental control life support system is 1 17kg.

The spacecraft structure adopts the principle of cabin layout, and all components of each subsystem are placed in a compact cabin, which is convenient for inspection and assembly and replacement in case of failure. From the fifth to the twelfth Gemini spacecraft, fuel cells are used. This battery has simple and compact structure, shock and vibration resistance, small volume, light weight and high specific power. In addition, the spacecraft also uses the ejection seat as an emergency life-saving means, which can provide a life-saving means for astronauts not only in the launch stage, but also in the landing stage.

So, what tasks did Gemini spacecraft mainly accomplish?

From 65438 to 0958, NASA headquarters and space mission team began to consider the goals and tasks of the American manned space program after Mercury manned space program. The space mission team headed by Gilrose and Fagert is particularly concerned about this. They believe that this plan should achieve two major goals on the basis of project mercury's completed tasks: the manned on-orbit flight time is greatly extended, reaching more than 1 week; Realize spacecraft in-orbit maneuver, rendezvous and docking.

196 1 year, the United States formulated the "Apollo moon landing plan", the task of which is more clear, that is, to explore and test new technologies to complete the moon landing mission, of which two aspects are the most important: First, to extend the manned flight time to two weeks to fully study the adaptability of people living and working in space; The second is to complete the on-orbit maneuver, rendezvous and docking of the two spacecraft. These two tasks will be completed during the moon landing. In this way, the Gemini project became an auxiliary project of the Apollo project.

As an independent transitional project, Gemini has made many groundbreaking achievements, providing Apollo with extremely valuable experience and technical achievements, including:

(1) has provided enough long-term flight experience to carry out the Apollo program, including physiology, medicine and life.

(2) The reliability and service life of the spacecraft under manned conditions are verified from the aspects of temperature, oxygen supply and pressure.

(3) The rendezvous and docking of the most important aircraft has been completed, which provides strong evidence for the lunar orbit docking scheme of manned landing on the moon.

(4) Completed more than 2 hours of extravehicular activities, accumulating experience for astronauts in lunar activities.

(5) The attitude control, maneuver and orbit change flight of the aircraft are realized. This is the basic task of the Apollo program.

(6) Controlled re-entry is realized, which improves the landing accuracy and provides greater guarantee for the safety of astronauts.

(7) The spacecraft is divided into several sections, and only the manned cabin is recovered when re-entering. Apollo spacecraft also adopted this model.

(8) The new fuel cell of Gemini spacecraft has been verified and improved, and successfully applied to Apollo spacecraft.

(9) Some problems existing in Gemini spacecraft, such as the reliability of attitude control system, the failure of life-saving system, the cumbersome spacesuit, and the difficulty in spacewalking, were widely absorbed and improved by Apollo program.

(10) Gemini also provides astronaut training and experience in space life. In addition, Gemini's flight provided direct guidance for the determination of Apollo mission.

(1 1) Long-distance ground communication has been developed and verified.

(12) The operation of each console station on the ground meets the requirements of long-range space flight.

In addition, the plan has also made many achievements in earth observation and scientific experiments.

Learning point

fuel battery

Fuel cell is a kind of power generation device that directly converts chemical energy existing in fuel and oxidant into electrical energy. Fuel and air are input into the fuel cell respectively, and the electricity generated is amazing. Externally, it has positive and negative electrodes and electrolyte, like a battery, but in essence, it is not a "power plant" but a "power plant". It has the advantages of high power generation efficiency and less environmental pollution.

This battery consists of one or more chemical solutions in which two metal rods called electrodes are inserted. The potential on one electrode is greater than that on the other, so if the two electrodes are connected by wires, electrons will flow from one electrode to the other through the wires. Such an electron flow is an electric current, which will continue as long as there is a chemical reaction in the battery. The battery of the flashlight is representative.