The spacecraft Phobos 1 and 2 were launched on 7 and 12 July 1988.
The mission was to have three stages: investigations of Sun and
interplanetary space during the flight from Earth to Mars; studies
of both Mars and Phobos during the orbit of the spacecraft around
Mars; and studies of Phobos as the spacecraft approached to within
50 m of its surface. Contact with Phobos 1 was lost on 1
September 1988 during the cruise phase; contact was lost with
Phobos 2 just before the third stage of the mission. However,
valuable data on Mars and Phobos were acquired prior to loss of
Mission Phase Information
Phase 1 - Cruise
Start Time: 1988-07-07
Stop Time: 1989-01-29
Phobos 2 was launched on July 12, 1988. The first correction of
the trajectory was made on July 21, 1988. On January 29, 1989,
a retarding impulse was applied and Phobos 2 was transferred
from Earth-to-Mars trajectory to the elliptical equatorial orbit
of a martian artificial satellite.
Phase 2 - Mars Orbit
Start Time: 1989-01-29
Stop Time: 1989-03-27
On January 29, 1989, a retarding impulse was applied and Phobos
2 was transferred from Earth-to-Mars trajectory to the
elliptical equatorial orbit of a martian artificial satellite.
The spacecraft's orbits were corrected several more times in
February, in order to achieve a circular orbit, almost the same
as that of Phobos, although somewhat higher. In March, several
intermediate corrections transferred the spacecraft into a
quasi-synchronous orbit with Phobos. Eventually, the craft was
transferred to an orbit closer to Phobos, and then guided closer
to Phobos itself. On March 27, 1989, after television imaging
of Phobos during which Phobos 2 changed its orientation so that
its field of view pointed at Phobos, radio contact was lost.
Mission Objectives Overview
The Phobos spacecraft was to have come as close as ~50 m to Phobos
which would have made it possible to obtain high-resolution
television images of the surface of Phobos, to study the elemental
and mineralogical composition of the regolith, the internal
structure of Phobos, and to put landers on the moon's surface.
Besides studies of Phobos, and the martian surface, atmosphere and
plasma environment of Mars, both of the Phobos spacecraft were to
make observations of the Sun and interplanetary space during the
flight from Earth to Mars.
Planetary and Space Sciences, Special issues on Phobos, Volume 39, Issues 1-2,
Sagdeev, R. Z., and Zakharov, A. V., Brief History of the Phobos Mission.
Nature, Vol. 341, October 19. 1989. p. 581-584