Shuttle missions, fuel cells

This mobile electrolyte system was used by Bacon in his historic alkaline fuel cells of the 1950s and in the Apollo mission fuel cells. It is almost universally used in terrestrial systems, but the Shuttle Orbiter vehicles use a static electrolyte, as described in the next section. 

An example of a practical application of stoichiometry is when we want to know how much water is formed when 0.25 mol 02 reacts with hydrogen in the space shuttle fuel cell (Fig. L.l). The designers of the mission know how much 02 the fuel cell can consume in a given period of time and need to know the mass of water that can be produced in that time. 

FIGURE L.l One of the three hydrogen-oxygen fuel cells used on the space shuttle. Although only one cell is needed to provide life-support electricity and drinking water shuttle flight rules require that all three be functioning. In April 1987, a mission of space shuttle Columbia was cut short when one of the fuel cells malfunctioned. 

Fuel cells have been reliably providing electricity to spacecraft since the 1960s, including the Gemini and Apollo missions as well as the space shuttle. The leading manufacturer of fuel cells for the National Aeronautics and Space Administration (nasa), United Technologies Corporation, has sold commercial units for stationary power since the early 1990s, with more than 200 units in service. 

The AFC type was originally created for the Apollo program, after that a modernized version has been developed and is even now in use to provide electrical power for shuttle missions. The electrolyte in this fuel cell is KOH, concentrated (85 wt %) for fuel cells operated at relatively high temperatures, that is, around 250°C, and less concentrated (35-50 wt %) for cells operated at lower temperatures, that is, less than 120°C [6,9,11], In the construction of these fuel cells, the electrolyte is retained in a matrix, typically asbestos, and a wide range of catalysts, for example, Ni, Ag, metal oxides, and noble metals, can be used for both the hydrogen and the oxygen electrodes [8,9],... 

The U.S. space program has supported extensive research to develop fuel cells. The shuttle missions use a fuel cell based on the reaction of hydrogen and oxygen to form water ... 

Advances in fuel cells were later accelerated by space and defense programs. Fuel cells found initial practical application with the Gemini (1962-1966) and the Apollo (1968-1972) spacecraft missions, and are still used to provide water and electricity for the Space Shuttle. The upgrade in fuel cell performance over the last four decades has been based on the development of new proton-conducting polymers, like Nafion and Gore-tex , ceramics and catalysts, as well as on greater insights into... 

In 1839, Sir William Robert Grove, a British lawyer and physicist, built the first fuel cell. More than 100 years later, fuel cells finally found a practical application—in space exploration. During short space missions, batteries can provide enough energy to keep the astronauts warm and to run electrical systems. But longer missions need energy for much longer periods of time, and fuel cells are better suited for this than batteries are. Today, fuel cells are critical to the space shuttle missions and to future missions on the international space station. 

The first successful applications of fuel cells were made in the US space missions Gemini in 1963 (PEFC) and Apollo in 1969 (7 kW AFC with a life time of more than 7000 h). Due to this experience, the most advanced AFC, however, not commercially viable, are found in space and military applications (satellites) with requirements of 65 % efficiency for 10,000 hours. The Space Shuttle employs three stacks with 12.5 kW each. Nevertheless, the AFC has recently lost its important role in the context of terrestrial development [29]. 

Fuel cells have the longest record of application in space exploration. Since the Gemini missions of NASA, fuel cells have been an indispensable technology in matmed space travel. The fuel cell systems used in the NASA space shuttles are based on alkaline fuel cells from UTC. Each orbiter has three systems of 7kWe each, which produce all electric power on board and provide potable water. These systems are hydrogen and oxygen fueled. 

Fuel cells deliver as much power as batteries weighing ten times as much. On a typical seven-day mission, the space shuttle fuel cells consumed 1500 pounds of hydrogen and generated 190 gallons of water. 

Aerospace. "Fuel cells have been used to provide power in spacecraft since the 1960s. Fuel cells were used in all 18 Apollo missions and over 100 space shuttle missions. In fact, all electrical power for NASA s space shuttle orbiter is provided by fuel cell power plants. In the orbiter, a complement of three 12 kW fuel cells produces aU onboard electrical power there are no backup batteries, and a single fuel ceU is sufficient to ensure safe vehicle return. In addition, the water produced by the electrochemical reaction is used for... 

Alkaline fuel cells (AFC) using aqueous KOH as electrolyte were the first type of fuel cells with practical applications at the beginning of the last century [9] but the formation of carbonate in the liquid electrolyte due to the CO2 contamination in the oxidant gas stream has limited its application to systems miming with pure oxygen, such as the fuel cells used by the NASA in the I960 Apollo space program, and currently used in the shuttle missions [10]. 

The alkaline fuel cell (AFC), also known as the Bacon fuel cell after its British inventor, is one of the most developed fuel-cell technologies and is the cell that flew Man to the Moon. NASA has used alkahne fuel cells since the mid-1960s, in Apollo-series missions and on the Space Shuttle. [2]... 

Despite many successfully specialized applications of fuel cells, such as UAV (unmanned aerial vehicles), submarines and the Apollo and Shuttle space missions [1-5], these applications are not the primary markets for fuel cell and hydrogen industries. To date the cost and quality of fuel cells are not comparable to those of the 1C engines or gas turbines. 

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