sentences:  On August 24, 1993, "Mars Observer" would turn 180-degrees and ignite the bipropellant thrusters to slow the spacecraft, entering into a highly elliptical orbit.Over the next three months, subsequent "transfer to lower orbit" (TLO) maneuvers would be performed as the spacecraft reached periapsis, eventually resulting in an approximately circular, 118-minute orbit around Mars.The primary mission was to begin on November 23, 1993, collecting data during one Martian year (approximately 687 Earth days).