... Trajectory Correction of the Spektr R Spacecraft Motion G. S. Zaslavskiya, V. A. Stepan'yantsa, A. G. Tuchina, A. V. Pogodinb, E. N. Filippovab, and A. I. Sheikhetb a Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Miusskaya pl. ... By definition, the ballistic lifetime of the spacecraft at current time instant t is provided when it flies above the Earth's surface at no less than a given altitude h l . ... 5 2014 TRAJECTORY CORRECTION OF THE SPEKTR R SPACECRAFT MOTION Table 1....