For the third time in four years, a PAMD (Payload Assist Module - Delta) solid rocket motor casing has been recovered after an uncontrolled atmospheric reentry. Coincidentally, all three reentries occurred during the month of January in the years 2001, 2004, and 2005. All were also utilized in the deployment of NAVSTAR spacecraft for the U.S. Global Positioning System (GPS).
The most recent event occurred on 13 January 2005 when the NAVSTAR 49 PAMD (2000-071C, U.S. Satellite Number 26607) reentered over Asia. The titanium casing of the STAR-48B solid rocket motor was subsequently found near Bangkok, Thailand (Figure 1). The egg-shaped object had a diameter of 1.2 m and a mass of more than 50 kg and closely resembled the casings found in Saudi Arabia in January 2001 (Orbital Debris Quarterly News, 6-2, p. 1) and in Argentina in January 2004 (Orbital Debris Quarterly News, 8-2, p. 1).
Each launch of a NAVSTAR spacecraft left a PAM-D in a highly elliptical orbit of approximately 200 km by 20,000 km. During the period January 2001 through January 2005, a total of 10 of these rocket bodies, with ages ranging from 3 to 10 years, reentered with a 30 percent recovery rate, a rate consistent with the ratio of Earth's land to water area. Orbital inclinations of the 10 stages ranged from 22° to 39°, limiting reentries to between 39° North and 39° South latitude.