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US Air Force Mulls New Space Launcher The US Air Force is considering a new class of space launch vehicle that would be optimised to carry payloads up to 10,000 lb (4,535kg). The desire for this type of launch system results from the preliminary findings of a continuing air force study of alternatives for future space launch systems, said Brig Gen Simon Worden, director of development and transformation in the service's Space and Missile Systems Center at Los Angeles Air Force Base, California. The air force envisages a 'responsive' spacelift force that can launch within hours or days of receiving clearance for a mission as opposed to the months currently taken to plan and carry out a launch. Scenarios for these systems include meeting the need for a surge in deploying intelligence, surveillance and reconnaissance satellites over a region during a crisis, quickly replenishing assets destroyed by an enemy or perhaps delivering weapons to strike targets across the globe (Jane's Defence Weekly 12 March). Gen Worden said the study shows that most future US military payloads will be under 10,000 lb, thereby raising the appeal of a launch vehicle in this class. The analysis, he told JDW on 16 October, also highlights that a hybrid launch system featuring a reusable first stage and an expendable upper stage is one of the most attractive options - if not the best choice in terms of cost and risk. Accordingly, Gen Worden said his office plans to present air force senior leadership with the option of conducting a flight demonstration of a hybrid 10,000 lb-class space launch system at the end of the decade. By today's standards a 10,000 lb-class payload is comparatively small. The air force's newest Boeing Delta IV and Lockheed Martin Atlas V family of boosters can carry from 15,000 lb to more than 40,000 lb into low-earth orbit, according to air force and industry officials. They will remain the bedrock of the inventory for several decades. Responsive systems will complement them at first and replace them eventually, Gen Worden said. The service is already pursuing next-generation responsive concepts for carrying smaller payloads weighing up to 1,000 lb into low-earth orbit, including tiny microsatellites that weigh only tens of pounds yet are expected to play an increasingly important role in US space initiatives. The goal is to begin flight demonstrations of launch designs in this class around 2007, said Gen Worden. As JDW went to press, he said the air force expected to announce within several weeks the designs that it will study in detail over the next six months. Concepts under consideration include solid-fuelled rocket motors, solid-fuelled systems with liquid oxidizers, liquid pressure-fed engines and air-launched designs, for example, using the C-17 Globemaster III strategic transport aircraft as a launch platform. In a related development, the air force, along with the US Navy and the Office of Force Transformation, plans to conduct around March 2004 the first flight of a novel, small reusable launch vehicle called the Falcon from Vandenberg Air Force Base, California. The Falcon, which is manufactured by Space Exploration Technologies Corporation (SpaceX), will carry a navy-built experimental electronics TacSat-1 microsatellite into low-earth orbit. The air force has interest in the Falcon because it offers improvements
in responsiveness over current systems, said Gen Worden. The two-stage
liquid-fuelled rocket booster has a re-usable first stage that is recovered
from the sea after use and can be prepared for the next launch within
one month, according to Elon Musk, SpaceX's founder and chief executive
officer. The booster will be able to carry a payload of up to 1,500 lb
into low-earth orbit at a fixed price of around $6 million, he said. Falcon also incorporates a 'hold before release' function that keeps the booster strapped to the launch pad during startup until it is verified that all systems are functioning properly, he said. Reproduced with Permission from Jane's Information
Group - Jane's Defence Weekly
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