The Leonid meteors and Space Shuttle risk assessment

The November 1999 Leonid meteor shower was videotaped with a low light leve l camera from the grounds of the National Aeronautics and Space Administrat ion (NASA) Johnson Space Center (JSC) in Houston, Texas. Additionally, obse rvations of the Leonids were recorded both digitally with the Liquid Mirror Telescope (LMT) and with a low light level camera at the JSC Observatory n ear Cloudcroft, New Mexico. The tapes were analyzed using a computer-automa ted meteor analysis system developed at JSC. These results were used to for m estimates of the Leonid mass-distribution. These estimates were compared to a Leonid mass distribution model used by NASA in risk assessment calcula tions associated with Space Shuttle missions. The observed data agrees favo rably with the NASA model in the 0.002 to 0.02 milligram range (based upon the LMT observations) and in the 0.02 to 0.2 gram range (based upon the low light level camera observations). This comparison supports the continued u se of this model.