Space exploration is a relatively dangerous endeavour. As of 2018, there have been 18 verified astronaut and cosmonaut fatalities during spaceflight. Astronauts have also died while training for space missions, including the Apollo 1 launch pad fire which killed an entire crew of three. There have also been some non-astronaut fatalities during spaceflight-related activities. See this list for more details.

For the purposes of this question, a 'spaceflight-related fatality' is any death of a human being resulting from accidents and incidents that occur during flight (from liftoff until the moment of landing), final preparation for flight, or training for manned space missions. For this question, a 'space mission' is any planned mission to reach an altitude of 100km or greater above mean sea level. 'Final preparation for flight' refers to events taking place from the moment a vehicle is in position at its launch site up until the moment of liftoff, cancellation, or other termination of the mission.

Not included are deaths resulting from testing, assembly or integration of manned or unmanned spacecraft (for instance an assembly worker falling from height, or being killed by a fire), or associated with the assembly, testing, maintenance or use of ballistic missile weapons.

How many such fatalities will occur between January 1 2020 and January 1 2025?

In the event that persons are declared missing as a result of a qualifying event, they shall be considered dead if and when they are declared to be presumed dead by competent authorities.