DIURNAL VARIATIONS OF THE GRAVITATIONAL VECTOR ON THE EARTH'S SURFACE AS A LIMITING FACTOR IN INTERPLANETARY SPACEFLIGHT. PRESENTATION OF THE HYPOTHESIS OF YURI ALEXANDROVICH FOMIN (1923-2001).

This paper presents the hypothesis of the Russian researcher Yuri A. Fomin (1923–2001) concerning the effect of diurnal oscillations of the resultant gravitational vector at the Earth's surface on biological structures, and the fundamental constraints this phenomenon is claimed to impose on crewed interplanetary spaceflight. According to Fomin, any body at the Earth's surface is subject to a combination of gravitational and inertial forces whose resultant vector remains nearly constant because the two components mutually compensate one another; as distance from Earth increases, Fomin argues, this compensation breaks down, producing a sharp and biologically hazardous change in the gravitational influence on an astronaut's organism. The paper discusses the daily peaks in the rate of change of the gravitational vector (around 4–8 a.m. and 4–8 p.m.), which Fomin associates with the aggravation of critical states in living organisms, as well as the claimed impossibility of fully reproducing a gravitational field by rotating a spacecraft. Based on these considerations, Fomin concludes that a crewed mission of long duration, such as a flight to Mars, would carry a high risk of crew death.