As most people say, the improvement of science and technology changed our society in many ways. Human lives have attained a higher level of convenience, variety, and vividness. Also, the curiosity of human nature influenced scientists, and the scientists pioneered the new field of science: the aerospace. This field is all about launching the manned spacecraft, sending the space satellites, creating the space shuttles and developing the aerospace technology. However, these works spend a lot of money. The weight of fuel and expendable launch system are the major factors of an expensive launch cost. To solve this problem, many international aerospace science institutes and private aerospace company have researched the way to decrease the weight of the rocket and improve the fuel-efficiency.
Depending on the type of fuel, spaceships are classified as a solid-fuel rocket or liquid-fuel rocket. The rocket using solid-fuel can radiate stronger thrust than the rocket using liquid-fuel can. Moreover, using solid-fuel rocket has fewer parts to manufacture than that of a liquid-fuel rocket, and it is easy to launch instantly after long-term storage. However, it is hard to control the rocket during the flight. On the other hand, the liquid-fuel rocket can control the magnitude of thrust. Therefore, most of the rockets use both solid and liquid type engines. By using them, aerospace science organization efficiently launch the rockets. Although these kinds of means are developed, reducing the launch cost is a hard problem to solve. Among other institutes and organizations, the company called ‘SpaceX’ came up with an innovative solution: using a reusable rocket.
‘SpaceX’ is a company that substitutes for transporting space freight such as space satellites, parts of space stations, and daily necessities for astronauts. It is the first private company to successfully launch, orbit, and recover a spacecraft. In addition, it is the first private company to send a spacecraft to the International Space Station, and the first to reuse an orbital rocket. Common rockets that use expendable launch system are launched once and then discard after the end of the flight. However, this company’s rockets use the reusable rockets that apply the reusable launch system (RLS, or reusable launch vehicle, RLV). RLS is a launch system that can launch a payload into space more than once. Most reusable rockets can be reused when the parts of them assemble again after their flight. Also, the reusable rocket of ‘SpaceX’ can take off and land vertically to its original launch center. Through these mechanisms, ‘SpaceX’ could save the launch cost by a factor of 6 compared to that of other institutes and organizations.
‘SpaceX’ has contracted with National Aeronautics and Space Administration(NASA) and other international aerospace science institutes. Also, it has developed many other rockets and dragon capsules such as Falcon 9 v1.2, Falcon Heavy, and Dragon V2. The prospect of this company seems very good.