The light-weight radioisotope heater unit (LWRHU) is a 238 PuO 2 -fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. Los Alamos National Laboratory designed, fabricated, and safety tested the LWRHU. The heat source consists of a hot-pressed 238 PuO 2 fuel pellet, a Pt-30Rh vented capsule, a pyrolytic graphite insulator, and a fineweave-pierced fabric graphite aeroshell assembly. To compare the performance of the LWRHUs fabricated for the Cassini mission with the performance of those fabricated for the Galileo mission, and to determine a failure threshold, two types of impact tests were conducted. A post-reentry impact test was performed on one of 180 flight-quality units produced for the Cassini mission and a series of sequential impact tests using simulant-fueled LWRHU capsules were conducted respectively. The results showed that deformation and fuel containment of the impacted Cassini LWRHU was similar to that of a previously tested Galileo LWRHU. Both units sustained minimal deformation of the aeroshell and fueled capsule; the fuel was entirely contained by the platinum capsule. Sequential impacting, in both end-on and side-on orientations, resulted in increased damage with each subsequent impact. Sequential impacting of the LWRHU appears to result in slightly greater damage than a single impact at the final impact velocity of 50 m/s.


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    Title :

    Light-weight radioisotope heater unit (LWRHU) impact tests


    Contributors:
    Reimus, M. A. H. (author) / Rinehart, G. H. (author) / Herrera, A. (author) / Lopez, B. (author) / Lynch, C. (author) / Moniz, P. (author) / El-Genk, Mohamed S. (editor) / Bragg, Mary J. (editor)

    Conference:

    Space technology and applications international forum - 1998 ; 1998 ; Albuquerque,New Mexico (USA)


    Published in:

    AIP Conference Proceedings ; 420 , 1 ; 1329-1337


    Publication date :

    1998-01-15


    Size :

    9 pages





    Type of media :

    Conference paper


    Type of material :

    Electronic Resource


    Language :

    English




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