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	<title>SpaceBuild &#187; Hybrid</title>
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	<link>http://www.spacebuild.net/s1</link>
	<description>Spacecraft technology</description>
	<lastBuildDate>Thu, 10 Feb 2011 20:59:53 +0000</lastBuildDate>
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		<title>Birth of a new hybrid</title>
		<link>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/172/</link>
		<comments>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/172/#comments</comments>
		<pubDate>Mon, 10 Jan 2011 20:31:23 +0000</pubDate>
		<dc:creator>admin</dc:creator>
				<category><![CDATA[Hybrid]]></category>
		<category><![CDATA[parrafin]]></category>
		<category><![CDATA[pentane]]></category>

		<guid isPermaLink="false">http://www.spacebuild.net/s1/?p=172</guid>
		<description><![CDATA[Although hybrids have been in development over the last 50 years, they have not made it into mainstream commercial applications because they did not produce as much thrust as liquid and solid systems. “Hybrid rockets tend to be sort of anaemic in their ability to produce thrust,” Cantwell said. This is because the fuel burns too slowly, relying on a process limited by the rate at which fuel evaporates and mixes with oxidizer. By contrast, the fuel and oxidizer are forced together in liquid systems and pre-mixed in solid systems. In 1995, the U.S. Air Force began to address this problem with a new type of hybrid fuel — a simple hydrocarbon, pentane, frozen using liquid nitrogen. The pentane burned three to four times faster than conventional fuels. The Air Force engineers explained their results by saying that less heat was required to gasify the pentane than was needed for conventional solid fuels. Cantwell and Karabeyoglu felt that this explanation was inadequate in light of the “blocking effect,” which limits the amount by which fuel evaporation can be increased simply by increasing the rate of heating. The effect occurs because the increasing evaporation pushes the flame away from the surface and blocks heat transfer even as the heating rate [...]]]></description>
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		<title>Hybrid rocket engine gels</title>
		<link>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/174/</link>
		<comments>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/174/#comments</comments>
		<pubDate>Mon, 10 Jan 2011 20:20:05 +0000</pubDate>
		<dc:creator>admin</dc:creator>
				<category><![CDATA[Hybrid]]></category>
		<category><![CDATA[butadiene]]></category>
		<category><![CDATA[hydrazine]]></category>
		<category><![CDATA[kerosene]]></category>
		<category><![CDATA[parrafin]]></category>
		<category><![CDATA[propellant gel]]></category>

		<guid isPermaLink="false">http://www.spacebuild.net/s1/?p=174</guid>
		<description><![CDATA[The major weakness of the solid-fuel rocket is the fact that, once lit, it burns to completion, and the only thing that can be done is to divert the thrust when it is no longer needed. The lack of burn control for solid-fuel rockets has led to the development of “hybrid” rockets that use a solid-fuel core along with a liquid oxidizer. The solid fuel component in a hybrid rocket is not impregnated with large quantities of an oxidizer material, which makes the rocket much safer to handle and store since it cannot burn efficiently on its own. Lockheed Martin has static-tested a hybrid motor with a butadiene &#8211; type solid fuel and liquid oxygen oxidizer. Lockheed Martin has also investigated the use of paraffins as propellants; “paraffins” in this case of course refers to the American usage of the term, meaning candle waxes and related solid hydrocarbons, and not the British usage of the term, which is what Americans call kerosene. Burt Rutan’s famous commercial suborbital manned spacecraft,  “ Spaceship One”, uses a hybrid propulsion system, with a butadiene-type solid fuel and nitrous oxide oxidizer. In this case, the propulsion system is designed for low cost and ease of handling instead of optimal thrust levels. Spaceship One is probably the first [...]]]></description>
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		<title>Paraffin based Hybrid engine technology</title>
		<link>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/170/</link>
		<comments>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/170/#comments</comments>
		<pubDate>Sun, 09 Jan 2011 20:07:18 +0000</pubDate>
		<dc:creator>admin</dc:creator>
				<category><![CDATA[Hybrid]]></category>
		<category><![CDATA[aluminum]]></category>
		<category><![CDATA[ammonium perchlorate]]></category>
		<category><![CDATA[parrafin]]></category>
		<category><![CDATA[solid]]></category>

		<guid isPermaLink="false">http://www.spacebuild.net/s1/?p=170</guid>
		<description><![CDATA[Paraffin was previously thought to be weak, easily broken and unsuitable for use as rocket fuel. But Cantwell’s team found that it is quite strong — at least twice as strong as conventional solid propellants. The paraffin they use as rocket fuel is the same material used as hurricane candles and sculptor’s wax. “Paraffin” is a generic name for a family of simple hydrocarbons with carbon chain lengths, ranging from 20 to 40. Different group members are suited to different applications. Safer, cheaper Paraffin fuel can contribute significantly to making it safer and cheaper to get into space. “If that were accomplished, human access to space would become more routine, and the ability to do scientific studies and commercialize the use of space would also increase dramatically,” Cantwell said. For example, scientists could undertake as many missions as necessary to clean up accumulated debris in our near-space environment. Conventional rocket fuels are either solids or liquids, but paraffin fuels are used in a hybrid system combining solid and liquid materials. An oxidizer such as oxygen or nitrous oxide is generally used with all fuel types to aid burning. Solid fuels include a rubberized material incorporating the oxidizer and other additives such as aluminum or ammonium perchlorate. The fuel &#8211; [...]]]></description>
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		<title>Engines of the future</title>
		<link>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/168/</link>
		<comments>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/168/#comments</comments>
		<pubDate>Sat, 08 Jan 2011 20:06:30 +0000</pubDate>
		<dc:creator>admin</dc:creator>
				<category><![CDATA[Hybrid]]></category>

		<guid isPermaLink="false">http://www.spacebuild.net/s1/?p=168</guid>
		<description><![CDATA[The success of Spaceship One could increase general interest in hybrid engines, especially for eventual use in space where the hydrazine is currently the prime propellant. Hydrazine is highly toxic, explosive, and the logistics of loading a spacecraft with the fuel are difficult. Therefore, hybrid fuels could be a viable alternative. SpaceDev has already begun an in-space effort with the Air Force Research Laboratory to develop a second stage engine to push small payloads around Earth, moving them to higher and lower orbits as needed. The company is developing its Streaker launch vehicle to use hybrid engines as well.]]></description>
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		<item>
		<title>Loading a hybrid engine</title>
		<link>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/166/</link>
		<comments>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/166/#comments</comments>
		<pubDate>Fri, 07 Jan 2011 20:02:52 +0000</pubDate>
		<dc:creator>admin</dc:creator>
				<category><![CDATA[Hybrid]]></category>

		<guid isPermaLink="false">http://www.spacebuild.net/s1/?p=166</guid>
		<description><![CDATA[To prepare Spaceship One for flight, rubber fuel is poured into a fuel casing and allowed to harden in a pie-like mold before being installed into the spacecraft’s aft fuselage. After a test flight, ground crews need only replace the fuel casing and attached nozzle, then top off the nitrous oxide tank to ready the craft for the next trip. Although SpaceDev’s HTPB mixture is a trade secret, it does include some non-HTPB material, none of which is toxic, explosive or environmentally unfriendly. Lower performance is a downside to hybrid engine systems in general, which is why SpaceDev is currently developing a high - performance version to rival some conventionally propelled rockets.]]></description>
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		<title>There has to be a way to shut off the motor</title>
		<link>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/159/</link>
		<comments>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/159/#comments</comments>
		<pubDate>Thu, 06 Jan 2011 19:59:44 +0000</pubDate>
		<dc:creator>admin</dc:creator>
				<category><![CDATA[Hybrid]]></category>

		<guid isPermaLink="false">http://www.spacebuild.net/s1/?p=159</guid>
		<description><![CDATA[Spaceship One’s engine, a composite structure designed by Scaled, consists primarily of two parts: a tank of nitrous oxide and a cylinder with the HTPB  fuel. Both SpaceDev and Miami, Florida based Environmental Aeroscience Corporation (eAc) contributed components of the engine. There has to be a way to shut off the motor … The propellant comes together in an eight-foot combustion chamber, where the liquid oxidizer is converted into a gas, then ignited by small pyros to start the engine. Spaceship One pilots can shut down the vehicle’s engine by closing a valve though which nitrous oxide enters the fuel chamber. In conventional rockets, propellant can be pre-mixed — as in the solid rocket boosters (SRBs) used NASA space shuttle — or sit in tanks that are filled just prior to launch, like liquid oxygen and hydrogen rockets. In both engine configurations, the are highly volatile and can be toxic to handle. The fact that the oxidizer and fuel are not molecularly mixed in hybrid engines makes them non-explosive. The HTPB fuel developed by SpaceDev is non-volatile, making it easier and safer to store than other materials. It is readily available in five-gallon drums and inexpensive. Nitrous oxide’s tendency to be self -pressurizing also does away with the need for complicated [...]]]></description>
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		<slash:comments>0</slash:comments>
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		<item>
		<title>Hybrid, a rubbery fuel</title>
		<link>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/157/</link>
		<comments>http://www.spacebuild.net/s1/propulsion/hybrid-propulsion/157/#comments</comments>
		<pubDate>Wed, 05 Jan 2011 19:57:46 +0000</pubDate>
		<dc:creator>admin</dc:creator>
				<category><![CDATA[Hybrid]]></category>

		<guid isPermaLink="false">http://www.spacebuild.net/s1/?p=157</guid>
		<description><![CDATA[Rocket propellants come in two parts, fuel and oxidizer, which work together to keep an engine burning. Spaceship One burns a material called hydroxy-terminated polybutadiene (HTPB), a common ingredient in tyre rubber, as fuel with nitrous oxide serving as the oxidizer. According to press statements by Scaled, the combination was chosen for Spaceship One after a lengthy study into potential engine systems. For SpaceShipOne, reaching space takes three things: a pilot, a spacecraft, and enough to propellant to rocket away from Earth. But the fuel in SpaceShipOne’s tank is about as exotic as the spacecraft’s design. SpaceShipOne, the first non-governmental crewed vehicle to reach space, uses a combination of rubber and nitrous oxide — also known as laughing gas — as it’s powerhouse. This is a very stable and non-toxic system. Based in Poway, California, SpaceDev is responsible for refuelling Spaceship One after each flight as well providing crucial elements of its hybrid rocket engine, a cross between traditional liquid and solid rocket motors. SpaceShipOne was designed by aerospace veteran Burt Rutan and his Mojave, California-based firm Scaled Composites. The craft represents one of 26 teams vying for the Ansari X Prize competition to privately build a vehicle capable of transporting three people 62 miles (100 kilometres) above Earth twice in two [...]]]></description>
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