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Senior Capstone Design Class  The senior design class had 34 students enrolled at the beginning of the 1997-98 academic year. It has been departmental policy to provide students the opportunity to select a spacecraft or an aircraft design project. The choices for this academic year were: 1) design a Reusable Launch Vehicle (RLV) for Northwest Airlines (NWA), and 2) design an AeroCar. The academic year began by assigning students to the following disciplines based on their job application letters: Aerodynamics, Structures / TPS, Systems Layout / Weights, and Propulsion / Trajectory Analysis. The spacecraft design team was lead by two Project Managers: Derek Gefroh and Joe Mueller. The spacecraft design teamÕs first task was to make a preliminary estimate of vehicle size. A brief market study showed that small satellites will be a major market for launch vehicles in the future. The decision was made to design a small RLV which would launch small satellites using a Boeing 747 (B747) as its first stage. Captain Dwayne Edelman from Northwest Airlines came to talk to the spacecraft design students during Fall Quarter to give them NWAs perspective on the design project. Cpt Edelman emphasized that the vehicle must fit within the existing NWA infrastructure and not require major aircraft modification or disruption of fleet operations. The students selected an autonomously controlled, thin wave rider / lifting body design with high hypersonic L/D and large cross-range to give NWA maximum operational flexibility. They called their vehicle Aeolus. Initial sizing showed that it was possible to mount Aeolus under the B747 fuselage. This substantially reduced the B747 structural modifications (AeolusÕs mounting hard points would be near existing aircraft landing gear hard points) and eliminate the need for a mating gantry. Several students took measuring tapes to NWA Maintenance to get accurate B747 dimensions. The final vehicle size was 2.4 meters high, 20.0 meters wide and 23.5 meters long; the vehicle weighed 61,235 kg at launch and 7,467 kg at landing. A typical launch/recovery involves the customer installing their satellite in a launch interface module and delivering it to the nearest airport served by NWA. NWA then transports and installs the satellite/module in the Aeolus after it is turned around following its previous flight. Aeolus is then rolled under and mounted to a NWA 747 freighter. The NWA 747 freighter crew flys to a preselected (orbital inclination) and environmentally acceptable launch-point. Launch is conducted autonomously by a launch team located at NWA Operations in Minneapolis. This method is selected to minimize B747 crew training and eliminate the need for extensive special equipment on-board the launch aircraft. The Aeolus then carries the satellite to orbits ranging from polar orbit (186 kg payload) to equatorial orbit (1050 kg payload). Aeolus is autonomously recovered at a NWA served airport consistent with its next launch.
 Students spent Winter Quarter testing their design. The aerodynamics discipline fab-ricated a subsonic wind tunnel model and tested it in the departmentÕs recirculating wind tunnel. The propulsion group fabricated a small model of the linear aerospace engine and tested it using 2000 psi air. The structures group measured the characteristics of composite materials used in their analysis of the primary tank and airframe structure. A special group was organized to look at launch and recovery trajectories by developing related simulations on the departmentÕs computers. Unfortunately, the class size was too small to continue the project through Spring Quarter. One student, Jim Chase, is continuing parts of the study as a part of a Undergraduate Research Oppor-tunities Program.
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