API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* Revised: Dec 06, 2024 Wind Spacecraft / (Earth) -8 https://wind.nasa.gov/ https://hpde.io/SMWG/Observatory/Wind https://www.nasa.gov/feature/goddard/2019/25-years-of-science-in-the-solar-wind BACKGROUND: The primary science objectives of the Wind mission are: - Provide plasma, energetic particle, and magnetic field data for magnetospheric and ionospheric studies - Investigate plasma processes occurring in the near-Earth solar wind - Provide baseline, 1 AU, ecliptic plane observations for inner and outer heliospheric missions Wind is a spin-stabilized spacecraft launched on a Delta II 7925-10 rocket 1994-Nov-1 @ 09:31 UTC from pad 17B at Cape Canaveral, FL. The spacecraft has visited many regions of the near-Earth space environment. For the first nine months of operation, Wind was placed in a double-lunar swingby orbit near the ecliptic plane, with apogee from 80 to 250 Earth radii and perigee of between 5 and 10 Earth radii. In this orbit, lunar gravity assists were used to keep its apogee over the day hemisphere of the Earth, and magnetospheric observations were made through several orbit passages. Wind was then temporarily inserted into a small amplitude "halo" orbit, about the sunward Sun-Earth gravitational equilibrium point (SEMB-L1), varying from 235 to 265 Earth radii (Re). In 2001 and 2002, Wind had a distant prograde orbit that took it +/- 300 Re leading and lagging Earth. This orbit provided a wide baseline to study solar wind structures and correlations. In 2003 (Nov 2003 to Feb 2004), Wind reached the L2 Lagrange point 240 Re anti-sunward from Earth providing a 500 Re spatial separation from ACE solar wind observations along with measurements of the distant Earth magnetotail. In late June of 2004, Wind used its last lunar gravity assist to insert into a L1 Lissajous orbit to observe the unperturbed solar wind prior to it impacting the magnetosphere of Earth, providing an approx. one-hour warning of changes in the solar wind. On June 26, 2020, Wind completed the first halo orbit insertion maneuver. A second was completed on August 31, 2020, a third on November 9, 2020. The maneuvers were necessary to prevent Wind from entering the solar exclusion zone around the solar disk, where solar radio emissions can interfere with spacecraft communications. The halo orbit is an ellipse tilted with respect to the ecliptic plane, while Lissajous has an out-of-plane (z) component oscillation decoupled from in-plane components. Wind currently has enough fuel to continue its mission at L1 into the 2070s. SPACECRAFT PHYSICAL CHARACTERISTICS: Bus size : 2.4 x 1.8 m cylinder Power : 370 Watts (body mounted solar panels) Launch mass: 1250 kg Dry mass : 950 kg Extension : Long wire spin-plane antennas, inertial booms, and spin-plane appendages to support sensors. Experiment booms deployed along both Z axes. Spin rate : 20 rpm (~3 s period) w/axis < 1 degree from normal to ecliptic (spacecraft +Z spin axis aligned with south ecliptic pole) SCIENCE INSTRUMENTS 1. Magnetic Field Investigation (MFI) 2. Solar Wind Experiment (SWE) Faraday Cup - Ion Data Electron Data 3. 3D Plasma Analyzer 4. SMS Suprathermal Particle Data 5. EPACT High Energy Particle Data 6. WAVES Radio and Plasma Waves Data 7. KONUS and TGRS Data (gamma ray) SPACECRAFT TRAJECTORY: This trajectory is a concatenation of weekly prediction provided by GSFC. Based on tracking data through 2024-December-02, prediction thereafter. Trajectory name Start Stop ---------------------------- ----------- ----------- Wind_merged 1994-Nov-01 2025-Feb-24 ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Mon Dec 9 18:13:09 2024 Pasadena, USA / Horizons ******************************************************************************* Target body name: Wind (spacecraft) (-8) {source: Wind_merged} Center body name: Earth (399) {source: DE441} Center-site name: iTelescope Obs., Siding Spring ******************************************************************************* Start time : A.D. 2024-Nov-30 00:00:00.0000 UT Stop time : A.D. 2024-Dec-01 00:00:00.0000 UT Step-size : 10 minutes ******************************************************************************* Target pole/equ : undefined Target radii : undefined Center geodetic : 149.0644, -31.2733577, 1.16499 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 149.0644,5457.31536,-3292.4397 {E-lon(deg),Dxy(km),Dz(km)} Center pole/equ : ITRF93 {East-longitude positive} Center radii : 6378.137, 6378.137, 6356.752 km {Equator_a, b, pole_c} Target primary : Earth Vis. interferer : MOON (R_eq= 1737.400) km {source: DE441} Rel. light bend : Sun {source: DE441} Rel. lght bnd GM: 1.3271E+11 km^3/s^2 Atmos refraction: NO (AIRLESS) RA format : HMS Time format : CAL Calendar mode : Mixed Julian/Gregorian RTS-only print : NO EOP file : eop.241209.p250307 EOP coverage : DATA-BASED 1962-JAN-20 TO 2024-DEC-09. PREDICTS-> 2025-MAR-06 Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s Table cut-offs 1: Elevation ( 0.0deg=YES),Airmass (>38.000=NO), Daylight (YES) Table cut-offs 2: Solar elongation ( 12.0,180.0=YES),Local Hour Angle( 0.0=NO ) Table cut-offs 3: RA/DEC angular rate ( 0.0=NO ) *************************************************************************************************************************************************************************************************************************************************** Date__(UT)__HR:MN R.A._____(ICRF)_____DEC Azi____(a-app)___Elev APmag S-brt r rdot delta deldot S-O-T /r S-T-O T-O-M/MN_Illu% RA_3sigma DEC_3sigma Sky_motion Sky_mot_PA RelVel-ANG *************************************************************************************************************************************************************************************************************************************************** $$SOE >..... Daylight Cut-off Requested .....< 2024-Nov-30 09:00 C 17 50 37.58 -21 30 30.9 253.328815 14.422053 n.a. n.a. 0.976043425296 -0.3720547 0.01080488900277 0.4091763 19.6061 /T 160.1812 30.9/ 1.0117 n.a. n.a. 1.6921879 41.556293 61.623887 2024-Nov-30 09:10 C 17 50 38.43 -21 30 18.3 252.183433 12.376985 n.a. n.a. 0.976041933196 -0.3719964 0.01080653204338 0.4099974 19.6026 /T 160.1846 30.8/ 0.9958 n.a. n.a. 1.7843784 44.694987 60.380243 2024-Nov-30 09:20 C 17 50 39.38 -21 30 05.6 251.022773 10.345374 n.a. n.a. 0.976040441330 -0.3719380 0.01080817696343 0.4101134 19.5995 /T 160.1877 30.7/ 0.9799 n.a. n.a. 1.8800352 47.567907 59.081030 2024-Nov-30 09:30 N 17 50 40.42 -21 29 53.0 249.844391 8.328245 n.a. n.a. 0.976038949698 -0.3718796 0.01080982093442 0.4095243 19.5968 /T 160.1905 30.6/ 0.9640 n.a. n.a. 1.9784849 50.201472 57.735511 2024-Nov-30 09:40 N 17 50 41.56 -21 29 40.4 248.645842 6.326685 n.a. n.a. 0.976037458300 -0.3718212 0.01081146113052 0.4082314 19.5944 /T 160.1928 30.5/ 0.9480 n.a. n.a. 2.0791133 52.620649 56.351449 2024-Nov-30 09:50 N 17 50 42.80 -21 29 27.9 247.424670 4.341847 n.a. n.a. 0.976035967136 -0.3717628 0.01081309473405 0.4062375 19.5924 /T 160.1948 30.4/ 0.9319 n.a. n.a. 2.1813599 54.848432 54.935322 2024-Nov-30 10:00 A 17 50 44.12 -21 29 15.4 246.178391 2.374961 n.a. n.a. 0.976034476207 -0.3717044 0.01081471894077 0.4035466 19.5908 /T 160.1965 30.3/ 0.9159 n.a. n.a. 2.2847122 56.905647 53.492517 2024-Nov-30 10:10 A 17 50 45.54 -21 29 03.0 244.904485 0.427338 n.a. n.a. 0.976032985512 -0.3716460 0.01081633096525 0.4001639 19.5895 /T 160.1977 30.2/ 0.8998 n.a. n.a. 2.3886995 58.810941 52.027511 >..... Elevation Cut-off Requested .....< >..... Daylight Cut-off Requested .....< $$EOE *************************************************************************************************************************************************************************************************************************************************** Column meaning: TIME Times PRIOR to 1962 are UT1, a mean-solar time closely related to the prior but now-deprecated GMT. Times AFTER 1962 are in UTC, the current civil or "wall-clock" time-scale. UTC is kept within 0.9 seconds of UT1 using integer leap-seconds for 1972 and later years. Conversion from the internal Barycentric Dynamical Time (TDB) of solar system dynamics to the non-uniform civil UT time-scale requested for output has not been determined for UTC times after the next July or January 1st. Therefore, the last known leap-second is used as a constant over future intervals. Time tags refer to the UT time-scale conversion from TDB on Earth regardless of observer location within the solar system, although clock rates may differ due to the local gravity field and no analog to "UT" may be defined for that location. Any 'b' symbol in the 1st-column denotes a B.C. date. First-column blank (" ") denotes an A.D. date. 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. NOTE: "n.a." in output means quantity "not available" at the print-time. SOLAR PRESENCE (OBSERVING SITE) Time tag is followed by a blank, then a solar-presence condition code: '*' Daylight (refracted solar upper-limb on or above apparent horizon) 'C' Civil twilight/dawn 'N' Nautical twilight/dawn 'A' Astronomical twilight/dawn ' ' Night OR geocentric ephemeris LUNAR PRESENCE WITH TARGET RISE/TRANSIT/SET EVENT MARKER (OBSERVING SITE) The solar-presence code column is immediately followed by another marker: 'm' Refracted upper-limb of Moon on or above apparent horizon ' ' Refracted upper-limb of Moon below apparent horizon OR geocentric The lunar presence marker (an ongoing state) can be over-ridden by a target event marker if an event has occurred since the last output step: 'r' Rise (target body on or went above cut-off RTS elevation) 'e' Elevation max (target body maximum elevation angle has occurred) 't' Transit (target body at or passed through observer meridian) 's' Set (target body on or went below cut-off RTS elevation) RTS MARKERS (TVH) Rise and set are with respect to the reference ellipsoid true visual horizon defined by the elevation cut-off angle. Horizon dip and yellow-light refraction (Earth only) are considered. Accuracy is < or = to twice the requested search step-size. 'R.A._____(ICRF)_____DEC' = Astrometric right ascension and declination of the target center with respect to the observing site (coordinate origin) in the reference frame of the planetary ephemeris (ICRF). Compensated for down-leg light-time delay aberration. Units: RA in hours-minutes-seconds of time, HH MM SS.ff{ffff} DEC in degrees-minutes-seconds of arc, sDD MN SC.f{ffff} 'Azi____(a-app)___Elev' = Airless apparent azimuth and elevation of target center. Compensated for light-time, the gravitational deflection of light, stellar aberration, precession and nutation. Azimuth is measured clockwise from north: North(0) -> East(90) -> South(180) -> West(270) -> North (360) Elevation angle is with respect to a plane perpendicular to the reference surface local zenith direction. TOPOCENTRIC ONLY. Units: DEGREES 'APmag S-brt' = The targets' approximate apparent visual magnitude and surface brightness. For planets and natural satellites, output is restricted to solar phase angles covered by observational data. Outside the observed phase angle range, "n.a." may be output to avoid extrapolation beyond the limit of model validity. For Earth-based observers, the estimated dimming due to atmospheric absorption (extinction) is available as a separate, requestable quantity. Surface brightness is the average airless visual magnitude of a square-arcsecond of the illuminated portion of the apparent disk. It is computed only if the target radius is known. Units: MAGNITUDES & MAGNITUDES PER SQUARE ARCSECOND 'r rdot' = The Sun's apparent range ("r", light-time aberrated) and range-rate ("rdot") relative to the target center, as seen by the observer. A positive "rdot" means the target center was moving away from the Sun, negative means moving toward the Sun. Units: AU and KM/S 'delta deldot' = Apparent range ("delta", light-time aberrated) and range-rate ("delta-dot") of the target center relative to the observer. A positive "deldot" means the target center is moving away from the observer, negative indicates movement toward the observer. Units: AU and KM/S 'S-O-T /r' = Sun-Observer-Target apparent SOLAR ELONGATION ANGLE seen from the observers' location at print-time. The '/r' column provides a code indicating the targets' apparent position relative to the Sun in the observers' sky, as described below: Case A: For an observing location on the surface of a rotating body, that body rotational sense is considered: /T indicates target TRAILS Sun (evening sky: rises and sets AFTER Sun) /L indicates target LEADS Sun (morning sky: rises and sets BEFORE Sun) Case B: For an observing point that does not have a rotational model (such as a spacecraft), the "leading" and "trailing" condition is defined by the observers' heliocentric ORBITAL motion: * If continuing in the observers' current direction of heliocentric motion would encounter the targets' apparent longitude first, followed by the Sun's, the target LEADS the Sun as seen by the observer. * If the Sun's apparent longitude would be encountered first, followed by the targets', the target TRAILS the Sun. Two other codes can be output: /* indicates observer is Sun-centered (undefined) /? Target is aligned with Sun center (no lead or trail) The S-O-T solar elongation angle is numerically the minimum separation angle of the Sun and target in the sky in any direction. It does NOT indicate the amount of separation in the leading or trailing directions, which would be defined along the equator of a spherical coordinate system. Units: DEGREES 'S-T-O' = The Sun-Target-Observer angle; the interior vertex angle at target center formed by a vector from the target to the apparent center of the Sun (at reflection time on the target) and the apparent vector from target to the observer at print-time. Slightly different from true PHASE ANGLE (requestable separately) at the few arcsecond level in that it includes stellar aberration on the down-leg from target to observer. Units: DEGREES 'T-O-M/MN_Illu%' = Target-Observer-Moon LUNAR ELONGATION angle and illuminated percentage. The apparent lunar elongation angle between target body center and Moon center, seen from the observing site, along with fraction of the lunar disk illuminated by the Sun. A negative lunar elongation angle indicates the target center is behind the Moon. Units: DEGREES & PERCENT 'RA_3sigma DEC_3sigma' = Uncertainty in Right-Ascension and Declination. Output values are the formal +/- 3 standard-deviations (sigmas) around nominal position. Units: ARCSECONDS 'Sky_motion Sky_mot_PA RelVel-ANG' = Total apparent angular rate of the target in the plane-of-sky. "Sky_mot_PA" is the position angle of the target's direction of motion in the plane-of-sky, measured counter-clockwise from the apparent of-date north pole direction. "RelVel-ANG" is the flight path angle of the target's relative motion with respect to the observer's line-of-sight, in the range [-90,+90], where positive values indicate motion away from the observer, negative values are toward the observer: -90 = target is moving directly toward the observer 0 = target is moving at right angles to the observer's line-of-sight +90 = target is moving directly away from the observer UNITS: ARCSECONDS/MINUTE, DEGREES, DEGREES 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/hrzn_batch.txt scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS Author : Jon.D.Giorgini@jpl.nasa.gov ***************************************************************************************************************************************************************************************************************************************************