The Uncontrolled Reentry of Progress-M 27M

Uncontrolled reentries of sizable space objects are becoming of growing concern due to the increase of space activities around the Earth and population on the ground. After providing an updated review of various aspects of the problem, this paper presents the exemplar case of Progress-M 27M, whose control was lost immediately after launch, on April 28, 2015, and which reentered on May 8. As in similar previous occurrences, the Space Flight Dynamics Laboratory of ISTI/CNR, in Pisa, was in charge of reentry predictions for the Italian civil protection authorities and space agency. The first prediction was issued in the morning of April 30, in the morning of May 7 the only potentially risky reentry trajectory over central Italy was identified, and in the afternoon of May 7, about 12 hours before the actual reentry, any residual risk for Europe and Italy was finally excluded.