PROCEDURE: maven_orbit_tplot PURPOSE: Loads MAVEN ephemeris information, currently in the form of IDL save files produced with maven_spice_eph.pro using spk predict kernels, and plots the spacecraft trajectory as a function of time (using tplot). The plots are color-coded according to the nominal plasma regime, based on conic fits to the bow shock and MPB from Trotignon et al. (PSS 54, 357-369, 2006). The wake region is simply the optical shadow in MSO coordinates (sqrt(y*y + z*z) < Rm ; x < 0). The available coordinate frames are: GEO = body-fixed Mars geographic coordinates (non-inertial) = IAU_MARS X -> 0 deg E longitude, 0 deg latitude Y -> 90 deg E longitude, 0 deg latitude Z -> 90 deg N latitude (= X x Y) origin = center of Mars units = kilometers MSO = Mars-Sun-Orbit coordinates (approx. inertial) X -> from center of Mars to center of Sun Y -> opposite to Mars' orbital angular velocity vector Z = X x Y origin = center of Mars units = kilometers USAGE: maven_orbit_tplot INPUTS: KEYWORDS: STAT: Named variable to hold the plasma regime statistics. DOMEX: Use a MEX predict ephemeris, instead of one for MAVEN. SWIA: Calculate viewing geometry for SWIA, based on nominal s/c pointing. IALT: Ionopause altitude. Highly variable, but nominally ~400 km. For display only - not included in statistics. RESULT: Named variable to hold the MSO ephemeris with some calculated quantities. EPH: Named variable to hold the MSO and GEO state vectors. DATE: Ephemeris version date. Several predict spk kernels have been generated. The latest was created on 21aug14 and covers the transition and science phases. The 28oct11 ephemeris is dated but includes an extended mission. CURRENT: Load the ephemeris from MOI to the current date + 2 weeks. This uses reconstructed SPK kernels, as available, then predicts. This is the default. EXTENDED: Alternate method of choosing the 28oct11 ephemeris. LOADONLY: Create the TPLOT variables, but do not plot. VARS: Array of TPLOT variables created. $LastChangedBy: dmitchell $ $LastChangedDate: 2014-10-16 14:04:52 -0700 (Thu, 16 Oct 2014) $ $LastChangedRevision: 16005 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/trunk/projects/maven/maven_orbit_tplot/maven_orbit_tplot.pro $ CREATED BY: David L. Mitchell 10-28-11