August 29, 2013
C. Acton

These four Lagrange Point SPK files were generated this date by Min-Kun Chung of the Navigation
and Mission Design Section at JPL, using a program named LTOOL and based on the just
released de431 planetary ephemeris. There is one file for each of the L1, L2, L4 and L5 Lagrange points;
none for the L3 Lagrange point.

Note that the NAIF IDs for these four Lagrange points are 391, 392, 394 and 395. Also note that the
ephemerides for the L1 and L2 points are centered at the earth-moon barycenter (ID = 3) while the
ephemerides for the L4 and L5 points are centered at the sun (ID = 10).

Summaries of the contents and coverage for each of these files is as follows:

Summary for: L1_de431.bsp
 
Body: 391 w.r.t. EARTH BARYCENTER (3)
      Start of Interval (ET)              End of Interval (ET)
      -----------------------------       -----------------------------
      1900 JAN 01 00:00:00.000            2151 JAN 01 00:00:00.000
 
 
Summary for: L2_de431.bsp
 
Body: 392 w.r.t. EARTH BARYCENTER (3)
      Start of Interval (ET)              End of Interval (ET)
      -----------------------------       -----------------------------
      1900 JAN 01 00:00:00.000            2151 JAN 01 00:00:00.000
 
 
Summary for: L4_de431.bsp
 
Body: 394 w.r.t. SUN (10)
      Start of Interval (ET)              End of Interval (ET)
      -----------------------------       -----------------------------
      1900 JAN 01 00:00:00.000            2151 JAN 01 00:00:00.000
 
 
Summary for: L5_de431.bsp
 
Body: 395 w.r.t. SUN (10)
      Start of Interval (ET)              End of Interval (ET)
      -----------------------------       -----------------------------
      1900 JAN 01 00:00:00.000            2151 JAN 01 00:00:00.000