What is a Space Shuttle Bus?

[Teagan]

In fact, it is a device that refers to an independently flying space vehicle added to the rocket's basic stage. After the rocket transports the upper stage to a certain orbit, it can fly autonomously and ignite multiple times, directly delivering one or more spacecraft into different orbital spaces. According to CCTV, the upper stage is vividly referred to as a "space shuttle bus." It takes over the rocket's flight in space, starting its journey hundreds of kilometers away from Earth, making it a true "expedition." Introduction to the Space Shuttle Bus: China's first "space shuttle bus," the Long March-3C/Expedition-1, will be used in future deep-space exploration missions such as lunar and Mars exploration. The Long March-3C/Expedition-1 adds an additional stage to the original three-stage Long March-3C rocket, turning it into a four-stage rocket. The main task of the four-stage rocket is to carry satellites that can directly enter orbit. Previously, three-stage rockets could only deliver satellites to a transfer orbit, meaning the orbit launched by the three-stage rocket was elliptical, and the satellite needed to adjust to a circular orbit. The improved four-stage rocket can directly send satellites to more distant target orbits without the need for further orbital adjustments. The flight of a three-stage rocket takes only about half an hour, while the four-stage rocket requires 4 to 6 hours of flight, reaching tens of thousands of kilometers into outer space. Features of the Space Shuttle Bus: It has autonomous orbital maneuverability, long in-orbit flight duration, and can generally ignite multiple times to meet the needs of different launch missions. It can deliver one or multiple payloads (such as satellites, space probes, etc.) to predetermined orbits, much like an airport shuttle bus. It combines the technical characteristics of both a carrier and a spacecraft, being an additional relatively independent stage or stages on the launch vehicle or reusable launch vehicle, capable of continuing flight with its own power to carry spacecraft. It can ignite multiple times. After the launch vehicle delivers it into space, the "space shuttle bus" can ignite multiple times to meet the needs of different launch missions. It has a long operational duration, exceeding that of the launch vehicle, ranging from several hours to several days or even tens of days. The Expedition-1 upper stage is the first to use liquid propellant, with an in-orbit operational time of 6.5 hours. It can sequentially deliver different "passengers" to different destinations. In space, the "space shuttle bus" takes over the rocket's flight mission and can directly deliver one or multiple spacecraft to their work locations through changes in flight trajectory.