Engineering topics

Vicente, F. A.

Publications and source records attributed to Vicente, F. A..

3 records

NASA NTRS1989

Electric propulsion applications enabled by space nuclear power

Electric propulsion promises the advantage of providing high Isp's for placing payloads into their assigned orbits. This translates into heavier payloads using a given lift capability or, conversely, the use of smaller boosters. To accomplish this, high electric powers are required. Space reactor power systems such as SP-100 enable this technology. The electric propulsion requirements needed, namely, their power requirements and the resulting payload masses and time-to-orbit, are shown. Also indicated are the missions most benefitting from the use of electric propulsion. An Interim Reference Mission is described, synthesizing the results shown, for demonstration purposes.

Vicente, F. A.↗

NASA NTRS1989

Space nuclear power applied to electric propulsion

Space reactor power systems with characteristics ideal for advanced spacecraft systems applications are discussed. These characteristics are: high power-to-weight ratio (15 to 33 W/kg); high volume density (high ballistic coefficient); no preferential orientation in orbit; long operational life; high reliability; and total launch and operational safety. These characteristics allow the use of electric propulsion to raise spacecraft from low earth parking orbits to operational orbits, greatly increasing the useful orbit payload for a given launch vehicle by eliminating the need for a separation injection stage. A proposed demonstration mission is described.

Vicente, F. A.↗

NASA NTRS1982

Preparation of large-particle-size monodisperse polystyrene latexes in microgravity

Three large-particle-size monodisperse latexes (3.44, 4.08, and 4.98 micron diameter) were prepared in an automated four-reactor apparatus on the third orbital mission of the 'Columbia' begun on March 22. Comparison with ground-based controls showed that the 4.98 micron-size flight sample was the more uniform; the uniformity at the other two sizes was about the same. The rates of polymerization in microgravity and on earth were the same within experimental error, demonstrating that radical-initiated vinyl addition polymerizations are unaffected by the weightless environment.

Vanderhoff, J. W.↗