133 lines
3.2 KiB
Plaintext
133 lines
3.2 KiB
Plaintext
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(word processor parameters LM=8, RM=78, TM=2, BM=2)
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Taken from KeelyNet BBS (214) 324-3501
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Sponsored by Vangard Sciences
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PO BOX 1031
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Mesquite, TX 75150
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August 3, 1990
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Courtesy of NASA BBS at 205 895-0028
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--------------------------------------------------------------------
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PRIMARY PROPULSION
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Electric propulsion for primary spacecraft thrust is of interest
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for both near-Earth and interplanetary missions. Near-Earth
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applications include the spiral-out maneuvers from low to high orbit
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and Earth escape.
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Once at high orbit the thruster may also be used for
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stationkeeping. Interplanetary missions include flights out of the
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ecliptic and flybys past, or rendezous with, asteroids, comets, and
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planets.
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A primary electric propulsion stage could offer large payload
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advantages as a commercial tug in conjunction with the space
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shuttle.
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The interest in electric propulsion derives mainly from the
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reduction in propellant requirements relative to chemical propulsion
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due to operation at increased specific impulse.
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One way to compare the capability of an electric propulsion
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spacecraft with that of a chemical system is to consider the total
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impulse delivered by two such systems.
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A 1500-kilogram electric propulsion spacecraft with 500
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kilograms of propellant can deliver slightly more total impulse than
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a 2914 Delta rocket stage, which has a mass of 5500 kilograms
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including 4500 kilograms of propellant. Although exact comparisons
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are subject to details of the propulsion system configuration, the
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comparison just given is illustrative of the propellant savings,
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and, hence, overall mission performance increases, achievable with
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electric propulsion.
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To explain more fully the characteristics of a primary electric
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propulsion system, the major elements are discussed in the following
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sections.
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--------------------------------------------------------------------
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If you have comments or other information relating to such topics as
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this paper covers, please upload to KeelyNet or send to the Vangard
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Sciences address as listed on the first page. Thank you for your
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consideration, interest and support.
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Jerry W. Decker.........Ron Barker...........Chuck Henderson
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Vangard Sciences/KeelyNet
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--------------------------------------------------------------------
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If we can be of service, you may contact
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Jerry at (214) 324-8741 or Ron at (214) 484-3189
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--------------------------------------------------------------------
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