“Until 8.30 in the morning, the population is invited to stay inside buildings, possibly away from windows and on floors not under the roof.” This is what we read in a note from the Municipality of Palermo about the expected uncontrolled return of a carrier rocket into the earth’s atmosphere, with the possibility of medium-sized debris falling to the ground. The National Civil Protection, in collaboration with the Italian Space Agency, has drawn up a map of the areas of the country at risk, which also includes north-eastern Sicily, albeit with low risk.
“In the unlikely event of debris falling – reads the note from the Municipality of Palermo -, we invite you to keep a distance of at least 20 meters, alerting the single emergency number 112”.
The Civil Protection of the Sicilian Region during the meeting of the National Operational Committee open to the Regions was informed that the uncontrolled return to the atmosphere of the second stage of the PRC carrier could affect the central southern sector of the national territory and in one of the possible trajectories it could cross Sicily in the northern territories. From the data communicated by the Italian Space Agency, the possible fall of fragments is currently foreseen in the night between Saturday 8 and Sunday 9 and, for the green orbit that could affect Sicily, from 4.11 local time with a temporal window of uncertainty by + or – 3 hours. The province that could be affected in this circumstance is Messina.
The time window and the ground impact trajectory will be defined more precisely in the next few hours. The return forecasts will be subject to continuous updates because they are linked to the behavior of the space vector itself and to the effects that the atmospheric density gives to falling objects, as well as to those related to solar activity. From what has been learned, it will be the relapse of hundreds of fragments with a maximum weight of a few hundred kg that fall towards the ground at a speed of about 200 km / h. The technical table will continue to follow all the reentry operations, providing analyzes and updates on the evolution of the operations until the actual return of the carrier to earth.
In Europe, surveillance is entrusted to the consortium for space surveillance Eusst (EU Space Surveillance and Tracking), of which the European Space Agency (ESA) is part and in which Italy participates with the Italian Space Agency (ASI), the National Institute of astrophysics (Inaf) and the center (Isoc Italian Space Surveillance and Tracking Operation Center) of the Italian Air Force in Pratica di Mare. Once processed, the data are transmitted to the Civil Protection at which the technical table is active, which confirms as “remote the hypothesis that it falls in Italy”.
Estimates on the orbits of this cylinder with a diameter of five meters and more than 30 in length are continuously updated and all the international organizations that are analyzing them agree that the impact in the atmosphere could occur in the early hours of Sunday morning. May 9, with a large margin of uncertainty.
European space surveillance and tracking radars indicate that the launcher’s stage descends as it rotates rapidly on itself, at such an angle that the East estimates that reentry can occur within latitude between 41.48 degrees North and 41.48 degrees South: a large area, but in which “most of the earth’s surface is covered by the ocean or by uninhabited areas, so the statistical probability of an impact on the ground in populated areas is low”.
Uncertainty is however a must and only a few hours before returning will it be possible to have more precise estimates and begin to exclude some areas. At the moment that area seen includes central-southern Italy, from Rome down, along with parts of Africa, the Americas and southern Asia and Australia, plus the Atlantic, Pacific and Indian oceans.
The stadium of the Lunga Marcia 5B had also fallen uncontrollably in 2020, but at the time the attention was too focused on the pandemic; the problem is that uncontrolled falls of space debris are much more frequent than people think.
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