API VERSION: 1.2
API SOURCE: NASA/JPL Horizons API

*******************************************************************************
 Revised: Sep 27, 2026              BepiColombo / (Sun)                    -121
                            http://sci.esa.int/bepicolombo/ 
 
 LAUNCH DATE:                                            MERCURY ARRIVAL DATE:
  2018-Oct-20 01:45 UTC                                      2026-Nov         

  Earth flyby: 2020-Apr-10, 04:24:58 UTC @ 19066 km, 352.85 deg E,-19.70 deg S

 LAUNCH VEHICLE:                                         LAUNCH SITE:
  Ariane 5                                                Kourou, French Guiana

 Note (2024-Sep-02): Due to unexpected electric currents between MTM's solar 
  arrays and the power extraction and distribution unit, electric propulsion 
  is reduced, requiring a one-year delay in Mercury arrival, to November 2026. 

 BACKGROUND:
  ESA's BepiColombo mission to orbit Mercury for one Earth year (four Mercury
  years) is composed of two spacecraft: the ESA Mercury Planetary Orbiter (MPO)
  and the ISAS/JAXA Mercury Magnetospheric Orbiter (MMO).

  MMO will be released once the MMO orbit is reached. MPO will be inserted 
  using chemical propulsion.

   1) MPO will study the surface and internal composition of Mercury 
   2) MMO will study the region around the planet influenced by its 
      magnetic field

  For the 8.2 year launch & cruise phases, MPO and MMO will be carried as part 
  of the Mercury Composite Spacecraft and released on arrival at Mercury. 

  There will be nine gravity assists during the cruise phase: 

   2020-Apr-10: Earth flyby
   2020-Oct-15: Venus flyby
   2021-Aug-11: Venus Flyby
   2021-Oct-01: First Mercury flyby
   2022-Jun-23: 2nd Mercury flyby
   2023-Jun-20: 3rd Mercury flyby
   2024-Sep-04: 4th Mercury flyby
   2024-Dec-01: 5th Mercury flyby
   2025-Jan-08: 6th Mercury flyby
   ....
   2026-Nov   : Mercury orbit insertion
   2028-Apr   : End of nominal mission
   2029-Apr   : End of extended mission

 OBJECTIVES:
  Study and understand the composition, geophysics, atmosphere, magnetosphere 
  and history of Mercury with following science objectives:

   * Investigate origin and evolution of a planet close to the parent star
   * Study Mercury form, interior structure, geology, composition and craters
   * Examine composition and dynamics of Mercury's vestigial atmosphere
   * Probe Mercury's magnetized envelope; structure and dynamics
   * Determine the origin of Mercury's magnetic field
   * Investigate polar deposits: their composition and origin
   * Perform a test of Einstein's theory of general relativity
 
 SPACECRAFT PHYSICAL PROPERTIES:
  Total launch mass  = 4100 kg

                         MPO                 MMO
  In Mercury orbit     1150 kg             275 kg  
  Payload mass           80 kg              45 kg
  Payload power        100-150 W            90 W
  Data volume          1550 Gbits/year     160 Gbits/year
  Average data rate    50 kbits/s            5 kbits/s
  Antenna              1-m X/Ka-band       0.8 m X-band
  Orientation          Nadir pointing      Spin axis at 90 deg. to Sun
  Stabilisation        3-axis stabilized   15-rpm spin-stabilised 

 BASIC ORBIT PARAMETERS AT MERCURY:
                       MPO (polar)        MMO (polar)
  peri/apo apses      480 x 1500 km      590 x 11640 km
  period                 2.3 hr            9.3 hr

 SPACECRAFT TRAJECTORY: 
  Trajectory from ESA. Data fit through 2026-Sep-21, prediction thereafter.

   Name                                    Start (TDB)          Stop (TDB)
   --------------------------------------  -----------------  -----------------
   bc_mpo_fcp_00235_20181020_20270411_v01  2018-Oct-20 02:14  2027-Apr-10 23:59
*******************************************************************************