API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: June 02, 2025 Mars 499 / 4 PHYSICAL DATA (updated 2025-Jun-02): Vol. mean radius (km) = 3389.92+-0.04 Density (g/cm^3) = 3.933(5+-4) Mass x10^23 (kg) = 6.4171 Flattening, f = 1/169.779 Volume (x10^10 km^3) = 16.318 Equatorial radius (km)= 3396.19 Sidereal rot. period = 24.622962 hr Sid. rot. rate, rad/s = 0.0000708822 Mean solar day (sol) = 88775.24415 s Polar gravity m/s^2 = 3.758 Core radius (km) = ~1700 Equ. gravity m/s^2 = 3.71 Geometric Albedo = 0.150 GM (km^3/s^2) = 42828.375662 Mass ratio (Sun/Mars) = 3098703.59 GM 1-sigma (km^3/s^2) = +- 0.00028 Mass of atmosphere, kg= ~ 2.5 x 10^16 Mean temperature (K) = 210 Atmos. pressure (bar) = 0.0056 Obliquity to orbit = 25.19 deg Max. angular diam. = 17.9" Mean sidereal orb per = 1.88081578 y Visual mag. V(1,0) = -1.52 Mean sidereal orb per = 686.98 d Orbital speed, km/s = 24.13 Hill's sphere rad. Rp = 319.8 Escape speed, km/s = 5.027 Perihelion Aphelion Mean Solar Constant (W/m^2) 717 493 589 Maximum Planetary IR (W/m^2) 470 315 390 Minimum Planetary IR (W/m^2) 30 30 30 ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Thu Aug 14 15:51:53 2025 Pasadena, USA / Horizons ******************************************************************************* Target body name: Mars (499) {source: mar099} Center body name: Sun (10) {source: DE441} Center-site name: BODY CENTER ******************************************************************************* Start time : A.D. 2025-Jan-01 00:00:00.0000 TDB Stop time : A.D. 2025-Jan-01 00:01:00.0000 TDB Step-size : 1 minutes ******************************************************************************* Center geodetic : 0.0, 0.0, 0.0 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 0.0, 0.0, 0.0 {E-lon(deg),Dxy(km),Dz(km)} Center radii : 695700.0, 695700.0, 695700.0 km {Equator_a, b, pole_c} Output units : AU-D Calendar mode : Mixed Julian/Gregorian Output type : GEOMETRIC cartesian states Output format : 2 (position and velocity) Reference frame : Ecliptic of J2000.0 ******************************************************************************* JDTDB X Y Z VX VY VZ ******************************************************************************* $$SOE 2460676.500000000 = A.D. 2025-Jan-01 00:00:00.0000 TDB X =-5.216858665681381E-01 Y = 1.525234576802456E+00 Z = 4.475559803760917E-02 VX=-1.271183490340250E-02 VY=-3.338839586395265E-03 VZ= 2.417788175776839E-04 2460676.500694444 = A.D. 2025-Jan-01 00:01:00.0000 TDB X =-5.216946942223875E-01 Y = 1.525232258137904E+00 Z = 4.475576593880412E-02 VX=-1.271180933472031E-02 VY=-3.338914323653169E-03 VZ= 2.417766240577524E-04 $$EOE ******************************************************************************* TIME Barycentric Dynamical Time ("TDB" or T_eph) output was requested. This continuous coordinate time is equivalent to the relativistic proper time of a clock at rest in a reference frame co-moving with the solar system barycenter but outside the system's gravity well. It is the independent variable in the solar system relativistic equations of motion. TDB runs at a uniform rate of one SI second per second and is independent of irregularities in Earth's rotation. CALENDAR SYSTEM Mixed calendar mode was active such that calendar dates after AD 1582-Oct-15 (if any) are in the modern Gregorian system. Dates prior to 1582-Oct-5 (if any) are in the Julian calendar system, which is automatically extended for dates prior to its adoption on 45-Jan-1 BC. The Julian calendar is useful for matching historical dates. The Gregorian calendar more accurately corresponds to the Earth's orbital motion and seasons. A "Gregorian-only" calendar mode is available if such physical events are the primary interest. REFERENCE FRAME AND COORDINATES Ecliptic at the standard reference epoch Reference epoch: J2000.0 X-Y plane: adopted Earth orbital plane at the reference epoch Note: IAU76 obliquity of 84381.448 arcseconds wrt ICRF X-Y plane X-axis : ICRF Z-axis : perpendicular to the X-Y plane in the directional (+ or -) sense of Earth's north pole at the reference epoch. Symbol meaning [1 au= 149597870.700 km, 1 day= 86400.0 s]: JDTDB Julian Day Number, Barycentric Dynamical Time X X-component of position vector (au) Y Y-component of position vector (au) Z Z-component of position vector (au) VX X-component of velocity vector (au/day) VY Y-component of velocity vector (au/day) VZ Z-component of velocity vector (au/day) ABERRATIONS AND CORRECTIONS Geometric state vectors have NO corrections or aberrations applied. Computations by ... Solar System Dynamics Group, Horizons On-Line Ephemeris System 4800 Oak Grove Drive, Jet Propulsion Laboratory Pasadena, CA 91109 USA General site: https://ssd.jpl.nasa.gov/ Mailing list: https://ssd.jpl.nasa.gov/email_list.html System news : https://ssd.jpl.nasa.gov/horizons/news.html User Guide : https://ssd.jpl.nasa.gov/horizons/manual.html Connect : browser https://ssd.jpl.nasa.gov/horizons/app.html#/x API https://ssd-api.jpl.nasa.gov/doc/horizons.html command-line telnet ssd.jpl.nasa.gov 6775 e-mail/batch https://ssd.jpl.nasa.gov/ftp/ssd/horizons_batch.txt scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS Author : Jon.D.Giorgini@jpl.nasa.gov *******************************************************************************