Which of the following descriptions about spaceships is correct?

The correct description of spacecraft means that spacecraft can run, observe and experiment in space outside the earth's atmosphere.

I. Historical development of spacecraft

1 On October 4th, the first spaceship in the world was the "artificial earth satellite1"launched by the Soviet Union, the first manned spaceship was the Soviet astronaut юа. Gagarin took the Oriental spaceship, and the first spaceship to send a man to the moon was Apollo 165438 of the United States.

The first plane with the characteristics of launch vehicle, spacecraft and airplane was the American space shuttle Columbia. In order to complete the space mission, the spacecraft must cooperate and coordinate with the space launch vehicle, the launch site and recovery facilities of the spacecraft, the TT&C space, the data acquisition network and the user station (network) to form a space system.

Spacecraft is the main body of space mission and the main component of space system.

Second, the role of equipment

The appearance of spacecraft has expanded the range of human activities from the earth's atmosphere to the vast space, which has made a leap in human ability to understand and transform nature and has had a great impact on social economy and social life.

Spacecraft runs outside the earth's atmosphere, getting rid of the obstacle of the atmosphere, and can receive all electromagnetic radiation information of cosmic celestial bodies, opening up all-band astronomical observation; Spacecraft flew from near-earth space to interplanetary space, realizing direct detection of space environment, close observation and direct sampling observation of the moon and planets of the solar system.

Spacecraft flying around the earth observe the earth from hundreds of kilometers to tens of thousands of kilometers, quickly collect a large number of electromagnetic radiation information about the earth's atmosphere, ocean and land, and directly serve meteorological observation, military reconnaissance and resource investigation.

Motion principle and system composition of spacecraft

First, the principle of motion

Under the action of celestial gravitational field, spacecraft basically moves in space according to the laws of celestial mechanics. There are two main ways of its movement: orbiting the earth and flying away from the earth to sail in interplanetary space.

The orbit around the earth is an elliptical orbit with the earth as one of the focuses or a circular orbit with the center of the earth as the center. The orbit of interplanetary space navigation is mostly a part of elliptical orbit with the sun as one of the focuses.

Second, the system composition

Spacecraft consists of several subsystems (or systems) with different functions, which are generally divided into two categories: dedicated systems and support systems. Dedicated systems, also known as payloads, are used to directly perform specific space tasks; Support system, also known as general load, is used to ensure the normal work of special systems.

The main difference between spacecraft with different purposes is that they are equipped with different special systems. There are many kinds of special systems, which vary with the tasks performed by spacecraft.