The entry of nuclear reactors into Earth's atmosphere resulting from an accidental or inadvertent abort of a space vehicle powered by nuclear-thermal rockets is investigated. The study is made for a typical piloted Mars mission vehicle incapacitated by an accident or malfunction during the Earth-arrival phase of the Mars-return journey due to simultaneous, multiple failures of its component systems. A single accident/abort scenario resulting in three entry possibilities is considered for a nominal hyperbolic in-bound approach velocity of 8 km/sec. The most severe case involving a direct entry is then analyzed over a broad range of approach velocities extending to 12 km/sec to include sprint-type missions. The results indicate that the severe surface heating, stagnation pressures, and g-loads are greater than 150 kW/sq cm, 300 atm, and 800-g, respectively. The wall heat transfer rate exceeds the value that can be accommodated by a carbon heatshield through radiation equilibrium prior to sublimation at 5500 K. These conditions are beyond our previous experience in crew safety, structural design, and thermal protection.


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    Title :

    Atmospheric entry of Mars-return nuclear-powered vehicles due to accidental termination of operations


    Contributors:

    Conference:

    AIAA, SAE, ASME, and ASEE, Joint Propulsion Conference and Exhibit ; 1993 ; Monterey, CA, United States


    Publication date :

    1993-06-01


    Type of media :

    Conference paper


    Type of material :

    No indication


    Language :

    English







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