Mission Overview
    ================
 
      Planet-A and MS-T5 were launched separately by
      M-3SII launchers.  The M-3SII launcher is a new
      three-stage solid-propellant rocket with - a solid
      kick-stage motor attached.  Both spacecraft were
      injected directly into a heliocentric comet
      transfer trajectory.  Immediately after launch,
      each spacecraft was tracked for about 8 h per day.
      They were be despun from 120 rpm, to about 30 rpm,
      using the thruster subsystem.  The spacecraft's
      attitude was initially automatically adjusted such
      that its spin axis was perpendicular to the
      Sun-spacecraft line.  During the subsequent ground
      contact, the spin rate was further reduced to 6.3
      rpm and the spin axis reoriented to be
      perpendicular to the ecliptic plane.  After the
      first 4-5 d of ranging and accurate orbit
      determination, a mid-course correction manoeuvre
      was carried out.  During the interplanetary cruise,
      attitude maintenance operations will have to be
      performed at 1Od intervals.
 
      Both spacecraft will make their closest approach to
      Halley near the time of the comet's post-perihelion
      crossing of the ecliptic plane.  MS-T5 has as its
      scientific objective: - to study the solar-wind
      plasma and, if possible, determine the signatures
      of the solar-wind/comet interaction at large
      distances from the comet.