  In 2020, over 60% of launches to low Earth orbit resulted in one or more
rocket bodies being abandoned in orbit and eventually returning to Earth in an
uncontrolled manner. When they do so, between 20 and 40% of their mass survives
the heat of atmospheric reentry. Many of the surviving pieces are heavy enough
to pose serious risks to people, on land, at sea, and in airplanes.
  There is no international consensus on the acceptable level of risk from
reentering space objects. This is sometimes a point of contention, such as when
a 20 tonne Long March 5B core stage made an uncontrolled reentry in May 2021.
Some regulators, including the US, France, and ESA, have implemented a 1 in
10,000 acceptable casualty risk (i.e., statistical threat to human life)
threshold from reentering space objects. We argue that this threshold ignores
the cumulative effect of the rapidly increasing number of rocket launches. It
also fails to address low risk, high consequence outcomes, such as a rocket
stage crashing into a high-density city or a large passenger aircraft. In the
latter case, even a small piece could cause hundreds of casualties. Compounding
this, the threshold is frequently ignored or waived when the costs of adherence
are deemed excessive.
  We analyse the rocket bodies that reentered the atmosphere from 1992 - 2021
and model the associated cumulative casualty expectation. We then extrapolate
this trend into the near future (2022 - 2032), modelling the potential risk to
the global population from uncontrolled rocket body reentries. We also analyse
the population of rocket bodies that are currently in orbit and expected to
deorbit soon, and find that the risk distribution is significantly weighted to
latitudes close to the equator. This represents a disproportionate burden of
casualty risk imposed on the countries of the Global South by major spacefaring
countries.
