Re-entry vehicles

Carbon—carbon composites are used in high temperature service for aerospace and aircraft appHcations as weU as for corrosion-resistant industrial pipes and housings. AppHcations include rocket nozzles and cases, aircraft brakes, and sateUite stmctures. Carbonized phenoHc resin with graphite fiber functioned effectively as the ablative shield in orbital re-entry vehicles for many years (92). 

When you write on a blackboard with chalk, you are not unduly inconvenienced if 3 pieces in 10 break while you are using it but if 1 in 2 broke, you might seek an alternative supplier. So the failure probability, Pf, of 0.3 is acceptable (just barely). If the component were a ceramic cutting tool, a failure probability of 1 in 100 (Pf= 10 ) might be acceptable, because a tool is easily replaced. But if it were the window of a vacuum system, the failure of which can cause injury, one might aim for a Pf of lO and for a ceramic protective tile on the re-entry vehicle of a space shuttle, when one failure in any one of 10,000 tiles could be fatal, you might calculate that a Pf of 10 was needed. 

Czarnecki, E. G., Stacey, J. T. and Zimmerman, D. K., Refractory Metal for Glide and Re-entry Vehicles, Met. Soc. Conference, 17 and Refractory Metals and Alloys, 2 (Edited by Semchyshen and Perlmutter), Interscience Publishers, New York (1%3)... 

The re-entry vehicle carried by each missile is so designed that its speed and trajectory are corrected by four small vernier rockets before it separates from the burned-out second stage. 

Pevelonment is continuing on a Trident II missile of much improved accuracy, and on the Mk 500 Evader maneuvering re-entry vehicle (MARV) to elude advanced Soviet ABMs Refs 1) M J JL Taylor J.W.R. Taylor. Missiles of the World , Charles Scribner s Sons, NY (1976), 154 2) R.T. Pretty, Ed, Jane s... 

Much less forgiving is the induced environment awaiting re-entry vehicles and spaceplanes. The induced environment depends strictly on the mission profile and results from a combination of launch, orbital and re-entry conditions. It includes temperatures as high as 1700 °C (Figure 3 following page), pressure, aerodynamic loads, acoustic vibrations and a hot plasma of very reactive and ions. 

With re-entry vehicles and spaceplanes, the material resistance to extremes of temperature becomes a matter of major concern. When spacecraft dive into the Earth s atmosphere, aerodynamic surfaces are exposed to high thermal and mechanical loads maximum heat fluxes of the order of MW/nr, dynamic pressure, shear stress, acoustic vibrations and material degradation put the vehicles structures to a hard test. Payload and passenger survival is committed to the efficiency of the thermal protection system (TPS) which has to maintain the internal temperature within appropriate limits through various energy dissipating mechanisms. 

Rocket motors last only for periods of a few minutes and their requirements are very different from those for supersonic or subsonic aircraft. Space re-entry vehicles can reach temperatures as high as 450-500°C, or even higher, for a period of 5-10 min. Black box flight recorders used in civil aircraft have to be able to withstand fires, with temperatures exceeding 1000°C for several minutes. Each of these materials has a different design specification and composition. 

The USA is the predominant user of carbon-carbon components, with some 80% of the market split more or less equally between aircraft brakes, re-entry vehicles and rocket nozzles. 

Cyanate ester Cyanogen hahde and alcohol or phenol Fibre composites for aircraft, rocket, missiles and re-entry vehicles... 

Because of their high aromatic content, phenolic resins absorb a lot of heat for their degradation. This is why they are used as an ablative material in re-entry vehicles. When a space vehicle re-enters the earth s atmosphere, due to tremendous friction with air, a lot of heat is generated. Phenolic resins can absorb the heat at the cost of its degradation, and stops the vehicle from deteriorating as a result of the extremely high temperature. 

Figure 15.2. Inflatable decelerator concepts. Courtesy of the Inflatable Re-entry Vehicle Experiment (IRVE) Project.

When a re-entry vehicle (RV) enters the atmosphere, an ionized sheath begins to form in front of the RV nose. An RCS dip can occur when the ionized layer is sufficiently thick that reflections from the nose... 

Currently, Yardney is in continuous production of secondary lithium-ion batteries, primary and secondary silver-zinc batteries and primary reserve silver-zinc batteries used on various Department of Defense applications. The primary battery applications include the Navy s Trident IID5 Fleet Ballistic Missile program, the Minuteman III ICBM, and primary power for the MK 21 re-entry vehicle. In 2012, the Trident II missile has achieved 143 successful test launches since 1989—a record unmatched by any other large ballistic missile or space launch vehicle. The most prominent Li-ion batteries made by Yardney have powered the Mars Explorer Rover missions (Spirit, Opportunity, and Curiosity), the USAF B-2 Bomber and Global Hawk aircraft, and the US Navy Advanced SEAL Delivery System (ASDS). One of the future applications for Yardney s Li-ion batteries is NASA s Orion Crew Exploration Vehicle (CEV). 

Apart from their widespread use in tactical air-warfare pyrotechnic, infrared decoy flares allegedly serve to increase the survivabihty of intercontinental ballistic missile warheads (re-entry vehicles) against any ballistic missile defense measures. Practice targets for ballistic missile defense purposes have been developed based on 155 mm parachute illuminant shells. A prototype shell received 2500 g Ailing of magnesium/Teflon/Hycar . This material yields burning times between 160 and 190 s and radiant intensities in the 600 W sr range in a particular band at 18 000 m altitude [11]. 

However, these categories are schematic and simpUstic they do not cover all types of spacecraft (e.g. spacecraft that can land or move on a celestial body, or an orbital structure, such as the International Space Station, whose size and inhabited character allow implementation of different solutions). Also, some spacecraft can cover several categories (e.g. the American Space Shuttle is both a launcher and an orbital transport (and re-entry) vehicle, and is sometimes used as an (inhabited) satellite). These categories are nevertheless useful to identify the main classes of needs and constraints, and to describe the main solutions, which is the subject of the following sections of this chapter. 

The carbon-carbon composites are employed in rocket motors, as friction materials in aircraft and high-performance automobiles, for hot-pressing molds, in components for advanced turbine engines, and as ablative shields for re-entry vehicles. 

Eagle Richer reserve batteries have found many applications in military and aerospace applications such as missiles and re-entry vehicles. They have also been used in mines. 

Eagle Picher develop and manufacture reserve batteries for a wide range of both military and aerospace applications. Eagle Picher lithium-thionyl chloride reserve batteries have found applications in mines, missiles, and re-entry vehicles where high-power, high energy density and multi-secdon, multi-tap configurations are required. 

The Skybolt missile was cancelled at the end of 1962, but the work on the warhead was carried to the new missile, Polaris, which carried three re-entry vehicles and warheads. 

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