China
Africa
Explore chapters and articles related to this topic
Materials
Published in Sumit Sharma, Composite Materials, 2021
Space shuttle nose cones: As the shuttle enters Earth’s atmosphere, temperatures as high as 3092°F (1700°C) are experienced. Carbon–carbon composite is a material of choice for the nose cone because it has the lowest overall weight of all ablative materials; high thermal conductivity to prevent surface cracking; high specific heat to absorb large heat flux; and high thermal shock resistance to low temperatures in space of –238°F (–150°C) to 3092°F (1700°C) due to reentry. Also, the carbon–carbon nose remains undamaged and can be reused many times.
Commercial Space Technologies
Published in Mohammad Razani, Commercial Space Technologies and Applications, 2018
Launch vehicles have the primary function of putting a spacecraft into an orbit or a suborbital trajectory. Most of the rocket stages fall away in sequence in the process of launching a satellite until the spacecraft reaches its planned orbit. In a conventional launch process, the first stage of the rocket propels the rocket from the launch pad, and then the second-stage rocket boosts the payload to orbit. Launch vehicles generally are used only once, although there are reusable launch vehicles that will be discussed in the next section. Figure 2.12 is a cross-section of a typical launch vehicle, the United Launch Alliance Atlas V.38 Its major components—from top to bottom—include the following (Figure 2.13): The nose cone or fairing, a structure made with a vented aluminum-honeycomb core and graphite epoxy covering, carries the payload. Manufacturers offer clients a choice of three payload fairings, depending on the size of the payload. The fairing protects the payload from atmospheric pressure changes and aerodynamic heating during launch.The second-stage rocket consists of fuel and oxygen tanks, control systems, and a rocket engine that carries the payload to orbit. The Atlas V is propelled by a single RL 10 Centaur engine and stainless steel fuel tanks, providing 22,300 pounds-force (lbf) of thrust, fueled by liquid hydrogen and liquid oxygen. The walls of the stainless steel tanks are insulated and so thin that they cannot support their own weight before they are pressurized; a design developed to maximize engine performance.Adapters connect the first and second stages of the rocket and provide the structure for housing vehicle electronics.The first stage consists of additional fuel and oxygen tanks, control systems, and rocket engines, sometimes supplemented with strap-on boosters. The Atlas V main booster is made of a special aluminum and, unlike the stage-two tanks, is structurally stable. The launch vehicle is fueled by rocket propellant (or highly purified kerosene) and liquid oxygen that provide 860,300 lbf of thrust. The RD 180 engine was developed in Russia and is produced by a U.S.–Russian joint venture.
Aerothermodynamic design and performance analysis of modified nose cones for space reentry vehicles
Published in International Journal of Ambient Energy, 2022
Raja Muthu, S. Siva Lakshmi, Santhoshini Babu
The fundamental basis for the design of any hypersonic vehicle is the analysis of aerodynamic and aerothermodynamic characteristics. Reentry vehicle is a portion of a spacecraft that is designed mainly to protect the crew and instruments within it during its return through Earth's atmosphere. It has to sustain intense heating effects caused during the high-speed flight through the atmosphere. The successful reentry of space vehicles is only become possible after the selection of the optimum design concept by considering aerodynamic heating, air loads and aerodynamic drag (Hankey 1988). The nose cone shape of any flying vehicles is important because it experiences the maximum amount of heat loads. There are many nose cone shapes used such as blunt-cone, hemisphere, ogive, parabola, spherical, etc. (Anderson 2008). Due to the high-speed passage of air around the reentry vehicles during its return, aerodynamic heating occurs whereby its kinetic energy is transformed into heat energy by skin friction on the surface of the body at a rate that depends on the viscosity and speed of the air. Aerodynamic heating can completely disintegrate even smaller objects and may cause objects to explode. When an entry body penetrates the atmosphere, the reentry velocities are extremely high and the corresponding Mach numbers are very huge (hypersonic velocities) (Harish, Naveen, and Rajgopal 2014). With the advent of hypersonic entry vehicles in the space age, aerodynamic heating became an overriding problem with regard to the very survival of the vehicle itself. It even dictates the shape of the vehicle. The shape of the nose cone is very important because when compared with all parts of the reentry vehicle, only the nosecone region experiences more heating loads (Anderson 2008).