Towards The Mechanics Of Photons.

Russian translation of Sänger’s Zur Mechanik der Photonen-Strahlantriebe (Oldenbourg, Munich, January 1956), number 5 in the series of his Stuttgart research institute for the physics of jet propulsion; the German title page is reproduced. In an editor’s foreword the physicist I. M. Khalatnikov calls it the first complete study of the mechanics of photon-rocket flight based on relativity, noting that Sänger leaves aside the engineering of such a rocket and its energy source, and that time dilation could let a crew return after several decades of Earth time.

Fourteen chapters treat the relativistic mechanics of the drive, including a ramjet-type photon drive, first from the crew’s and then from an outside observer’s viewpoint: mass intake and ejection, adiabatic and diabatic acceleration, kinematics, dynamics, and the processes of setting the rocket in motion. Followed by a bibliography. Printed in Budapest.