Search NASA⌕ Search

Engineering topics

Martelli, G.

Publications and source records attributed to Martelli, G..

Catastrophic disruption experiments: Recent results

This paper presents a review of the progress in the field of catastrophic disruption experiments over the past 4 years, since the publication of the review paper by Fujiwara et al. (1989). We describe the development of new techniques to produce shattering impacts relevant to the study of the collisional evolution of the asteroids, and summarize the results from numerous experiments which have been performed to date, using a variety of materials for both the impactor and the targets. Some of these, such as ice-on-ice, loose aggregates and pressurized targets, are quite new and have provided novel and exciting results. Some of the gaps existing previously in the data on fragment ejection-angle distributions, as well as translational and rotational velocity fields (including fine fragments) have been filled, and these new results will be surveyed.

Martelli, G.↗

Magnetic field and shock effects and remanent magnetization in a hypervelocity impact experiment

The impact of aluminum projectiles onto high-alumina terrestrial basalt blocks at 13-15 km/s in the presence of a variable magnetic field is studied. Plasma production but not field production was detected, and characteristics of the remanence and the shocked basalt are reported. Mineralogical data suggest that the magnetization acquired in the material near the craters is shock remanence. The experimental results might indicate that shock effects or possibly thermoremanence in ejecta fragments, may be responsible for part of the magnetization of the lunar surface.

Srnka, L. J.↗