Updated Ephemeris for ISEE-3 at JPL Horizons for August 2014

Updated Ephemeris for ISEE-3 at JPL Horizons 3 July 2014

Revised: Jul 15, 2014 ISEE-3/ICE Spacecraft

UPDATE (2014-Jul-15): Trajectory updated to JPL solution #41 (s41), based on 48 coarse Arecibo plane-of-sky angular measurements spanning May 22 - Jul 15.


Plane-of-sky uncertainties (units are arcseconds, km, km/s):


Date__(UT)__HR:MN RA_3sigma DEC_3sigma RNG_3sigma RNGRT_3sig
2014-Aug-02 00:00 780.766 642.014 14031.3850 0.0570105
2014-Aug-04 00:00 1479.369 1256.082 10321.1032 0.0552189
2014-Aug-05 00:00 2182.470 1885.499 11009.1841 0.0543265
2014-Aug-06 00:00 3478.347 3051.582 12681.5228 0.0538118
2014-Aug-07 00:00 6285.085 5509.371 13931.3196 0.0551457
2014-Aug-08 00:00 14020.531 11018.574 11569.0536 0.0645683
2014-Aug-10 00:00 7590.364 5316.623 27551.0800 0.0865967
2014-Aug-12 00:00 22710.084 17508.146 30241.9692 0.1064071
2014-Aug-14 00:00 31843.193 22694.977 18375.5356 0.0156532
2014-Aug-16 00:00 35268.764 24040.205 16171.9713 0.0269640
2014-Aug-18 00:00 36951.706 24472.608 33196.4787 0.0499405
2014-Aug-20 00:00 37896.044 24616.796 53638.2302 0.0630939
2014-Aug-22 00:00 38453.318 24650.921 74030.4945 0.0704983
2014-Aug-24 00:00 38773.710 24634.617 93572.7670 0.0742269
2014-Aug-26 00:00 38930.728 24588.886 111937.097 0.0754814
2014-Aug-28 00:00 38964.476 24520.542 128970.257 0.0750356
2014-Aug-30 00:00 38899.203 24431.021 144616.210 0.0734299
2014-Sep-01 00:00 38751.206 24319.948 158882.594 0.0710662

UPDATE (2014-Jul-10): Trajectory updated to JPL solution #36 (s36), based on 45 coarse Arecibo plane-of-sky angular measurements spanning May 22 - Jul 09.

UPDATE (2014-Jul-03): Trajectory update from ISEE-3 Reboot based on Arecibo angular data and DSN two-way Doppler.

UPDATE (2014-Jun-23): Trajectory updated to JPL solution #32 (s32), based on 42 coarse Arecibo plane-of-sky angular measurements spanning May 22 - Jun 23 ... (not delay/Doppler).

UPDATE (2014-Jun-13): Trajectory updated to JPL solution #27 (s27), based on coarse Arecibo plane-of-sky angular measurements (not delay/Doppler).

UPDATE (2014-Jun-09): Trajectory updated to JPL solution #24 (s24), based on coarse Arecibo plane-of-sky angular measurements (not delay/Doppler).

UPDATE (2014-Jun-05): Trajectory updated to JPL solution #21 (s21), based on coarse Arecibo plane-of-sky angular measurements (not delay/Doppler).

UPDATE (2014-Jun-03): Trajectory updated to JPL solution #17 (s17), based on coarse Arecibo plane-of-sky angular measurements (not delay/Doppler).

UPDATE (2014-Jun-01): The trajectory has been updated to JPL solution #6 (s6), based on coarse Arecibo plane-of-sky angular measurements (not delay/Doppler).

UPDATE (2014-May-23): While too distant/small for radar echos, Arecibo obtained one plane-of-sky measurement about 0.39 deg (RSS) from this trajectory. A full, three dimensional orbit solution update is not yet possible, but will be made available here if/when it is.

UPDATE (2014-Mar-10): Reacquired carrier signal by AMSAT-DL/Bochum: http://www.amsat-dl.org/index.php/news-mainmenu-97/199-ice-satellite-received-in-bochum

SPACECRAFT TRAJECTORY


Trajectory name Start Stop
-------------------------------------------------- ----------- -----------
ice_s41 2014-May-16 2014-Aug-01

BACKGROUND: Launched 1978-Aug-12 15:12 UTC on a Delta 2914, the International Sun-Earth Explorer 3 was the third of a trio of spacecraft launched to study interplanetary space; Earth's magnetosphere and its interaction with the solar wind. ISEE-1 and 2 were Earth-orbiters. ISEE-3 was the first spacecraft to orbit a libration point (Earth-Sun L1, about 1.5 million km from Earth) beginning 1978-Nov-20. The mission was managed by NASA/GSFC.

After completion of its primary mission, it was renamed International Cometary Explorer (ICE) and sent to study comet Giacobini-Zinner and comet Halley. Fifteen maneuvers and five lunar passes (the last on 1983-Dec-22, at an altitude of 119.4 km, not far from the Apollo 11 landing site on the surface) were used to maneuver it to the heliocentric escape orbit achieved 1983-Dec-22.

It was the first spacecraft to fly past a comet, being initially maneuvered to a point 26550 km behind comet Giacobini-Zinner on 1985-Jun-05 so as to sample the tail, then approached the nucleus to within 7862 km on 1985-Sep-11 with a relative velocity of 20.7 km/s, confirming for the first time theories that comets are 'dirty snowballs' of ice and rock. The spacecraft later flew between the Sun and comet Halley on 1986-Mar-28, 31 million km from the comet.

NASA headquarters approved an update to the ICE mission in 1991: a heliospheric mission consisting of investigations of coronal mass ejections in coordination with ground-based observations, continued cosmic ray studies, and special-period observations such as when ICE and Ulysses were on the same solar radial line. By May 1995, ICE was being operated with only a low duty cycle, with some support being provided by the Ulysses project for data analysis. Two years later, on May 5, 1997, NASA authorized termination of operations.

Twelve of its thirteen instruments were working and the spacecraft retained a 150 m/s delta-V fuel capacity.

At 20:49 UTC on September 18, 2008, the 70-meter Goldstone antenna DSS-14 locked onto the carrier signal of the ISEE-3/ICE spacecraft, still transmitting and relatively close to the position based on predictions from several years earlier. The remainder of the 3-hour track was then used to gather Doppler tracking data for future use.

When last contacted, the spacecraft was on a trajectory that will bring it close to Earth in August 2014.

Current transmitter hardware of the Deep Space Network no longer includes the equipment needed to transmit commands to ISEE-3 without some modification, but the spacecraft's transmitter signal could still be detected and down-linked data understood.

PHYSICAL DATA:
Cylindrical: 1.7-m diameter x 1.6-m height
Mass : 390 kg (478 kg at launch)
Spin rate : 20 rpm
Solar power: 160 watts (cells cover body surface)
Two 3-meter booms carrier magnetometer and plasma wave sensors.
Four antennas span 91-meters for radio and plasma wave studies.
Results

*******************************************************************************
Ephemeris / WWW_USER Thu Aug  7 09:18:26 2014 Pasadena, USA      / Horizons    
*******************************************************************************
Target body name: ICE Spacecraft (-111)           {source: Horizons_SPK:user_input_}
Center body name: Earth (399)                     {source: DE-0431LE-0431}
Center-site name: GEOCENTRIC
*******************************************************************************
Start time      : A.D. 2014-Jul-04 00:00:00.0000 UT      
Stop  time      : A.D. 2014-Aug-03 00:00:00.0000 UT      
Step-size       : 1440 minutes
*******************************************************************************
Target pole/equ : No model available
Target radii    : (unavailable)                                                
Center geodetic : 0.00000000,0.00000000,0.0000000 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 0.00000000,0.00000000,0.0000000 {E-lon(deg),Dxy(km),Dz(km)}
Center pole/equ : High-precision EOP model        {East-longitude +}
Center radii    : 6378.1 x 6378.1 x 6356.8 km     {Equator, meridian, pole}    
Target primary  : Earth
Vis. interferer : MOON (R_eq= 1737.400) km        {source: DE-0431LE-0431}
Rel. light bend : Sun, EARTH                      {source: DE-0431LE-0431}
Rel. lght bnd GM: 1.3271E+11, 3.9860E+05 km^3/s^2                              
Atmos refraction: NO (AIRLESS)
RA format       : HMS
Time format     : CAL 
EOP file        : eop.140806.p141028                                           
EOP coverage    : DATA-BASED 1962-JAN-20 TO 2014-AUG-06. PREDICTS-> 2014-OCT-27
Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s 
Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass (>38.000=NO), Daylight (NO )
Table cut-offs 2: Solar Elongation (  0.0,180.0=NO ),Local Hour Angle( 0.0=NO )
**************************************************************************************************************
 Date__(UT)__HR:MN     R.A._(ICRF/J2000.0)_DEC  APmag  S-brt            delta      deldot    S-O-T /r    S-T-O
**************************************************************************************************************
$$SOE
 2014-Jul-04 00:00     08 39 57.97 +18 03 09.0   n.a.   n.a. 0.04097420055495  -2.3000732  25.8956 /T 153.0580
 2014-Jul-05 00:00     08 40 55.52 +17 57 22.0   n.a.   n.a. 0.03965389761786  -2.2718162  25.1877 /T 153.8264
 2014-Jul-06 00:00     08 41 51.46 +17 51 32.2   n.a.   n.a. 0.03834988413778  -2.2436642  24.4742 /T 154.5985
 2014-Jul-07 00:00     08 42 45.78 +17 45 38.9   n.a.   n.a. 0.03706211390299  -2.2155673  23.7551 /T 155.3744
 2014-Jul-08 00:00     08 43 38.52 +17 39 41.3   n.a.   n.a. 0.03579056835453  -2.1874811  23.0307 /T 156.1537
 2014-Jul-09 00:00     08 44 29.72 +17 33 38.3   n.a.   n.a. 0.03453525074589  -2.1593768  22.3011 /T 156.9363
 2014-Jul-10 00:00     08 45 19.47 +17 27 28.5   n.a.   n.a. 0.03329617243119  -2.1312582  21.5670 /T 157.7215
 2014-Jul-11 00:00     08 46 07.94 +17 21 10.1   n.a.   n.a. 0.03207332835889  -2.1031817  20.8289 /T 158.5087
 2014-Jul-12 00:00     08 46 55.33 +17 14 41.0   n.a.   n.a. 0.03086666141849  -2.0752733  20.0881 /T 159.2967
 2014-Jul-13 00:00     08 47 41.96 +17 07 58.6   n.a.   n.a. 0.02967602011333  -2.0477330  19.3459 /T 160.0842
 2014-Jul-14 00:00     08 48 28.20 +17 00 59.9   n.a.   n.a. 0.02850111926222  -2.0208193  18.6041 /T 160.8693
 2014-Jul-15 00:00     08 49 14.52 +16 53 41.2   n.a.   n.a. 0.02734151537765  -1.9948152  17.8648 /T 161.6499
 2014-Jul-16 00:00     08 50 01.43 +16 45 58.8   n.a.   n.a. 0.02619660436262  -1.9699873  17.1305 /T 162.4234
 2014-Jul-17 00:00     08 50 49.51 +16 37 47.9   n.a.   n.a. 0.02506564085731  -1.9465543  16.4040 /T 163.1872
 2014-Jul-18 00:00     08 51 39.36 +16 29 03.7   n.a.   n.a. 0.02394777118630  -1.9246717  15.6882 /T 163.9382
 2014-Jul-19 00:00     08 52 31.62 +16 19 40.6   n.a.   n.a. 0.02284206951891  -1.9044353  14.9864 /T 164.6731
 2014-Jul-20 00:00     08 53 27.00 +16 09 32.1   n.a.   n.a. 0.02174756937694  -1.8858925  14.3023 /T 165.3883
 2014-Jul-21 00:00     08 54 26.23 +15 58 30.6   n.a.   n.a. 0.02066328697279  -1.8690582  13.6399 /T 166.0797
 2014-Jul-22 00:00     08 55 30.16 +15 46 27.3   n.a.   n.a. 0.01958823633798  -1.8539271  13.0041 /T 166.7426
 2014-Jul-23 00:00     08 56 39.74 +15 33 11.5   n.a.   n.a. 0.01852143787508  -1.8404836  12.4002 /T 167.3714
 2014-Jul-24 00:00     08 57 56.09 +15 18 30.1   n.a.   n.a. 0.01746192219037  -1.8287090  11.8351 /T 167.9595
 2014-Jul-25 00:00     08 59 20.52 +15 02 07.0   n.a.   n.a. 0.01640873055237  -1.8185858  11.3167 /T 168.4987
 2014-Jul-26 00:00     09 00 54.68 +14 43 41.5   n.a.   n.a. 0.01536091263358  -1.8101031  10.8553 /T 168.9790
 2014-Jul-27 00:00     09 02 40.62 +14 22 47.2   n.a.   n.a. 0.01431752163781  -1.8032603  10.4636 /T 169.3877
 2014-Jul-28 00:00     09 04 40.96 +13 58 49.4   n.a.   n.a. 0.01327760661679  -1.7980732  10.1579 /T 169.7083
 2014-Jul-29 00:00     09 06 59.20 +13 31 01.8   n.a.   n.a. 0.01224020174825  -1.7945785   9.9595 /T 169.9196
 2014-Jul-30 00:00     09 09 40.04 +12 58 20.3   n.a.   n.a. 0.01120431255867  -1.7928392   9.8969 /T 169.9932
 2014-Jul-31 00:00     09 12 50.10 +12 19 14.5   n.a.   n.a. 0.01016889960441  -1.7929480  10.0088 /T 169.8905
 2014-Aug-01 00:00     09 16 38.96 +11 31 32.2   n.a.   n.a. 0.00913286153545  -1.7950252  10.3499 /T 169.5566
 2014-Aug-02 00:00     09 21 21.07 +10 31 51.6   n.a.   n.a. 0.00809502378065  -1.7991974  11.0020 /T 168.9101
 2014-Aug-03 00:00     09 27 19.41 +09 14 49.0   n.a.   n.a. 0.00705415265027  -1.8055198  12.0938 /T 167.8222
$$EOE
**************************************************************************************************************
Column meaning:

TIME

Prior to 1962, times are UT1. Dates thereafter are UTC. Any 'b' symbol in the 1st-column denotes a B.C. date. First-column blank (" ") denotes an A.D. date. Calendar dates prior to 1582-Oct-15 are in the Julian calendar system. Later calendar dates are in the Gregorian system.

Time tags refer to the same instant throughout the universe, regardless of where the observer is located.

The dynamical Coordinate Time scale is used internally. It is equivalent to the current IAU definition of "TDB". Conversion between CT and the selected non-uniform UT output scale has not been determined for UTC times after the next July or January 1st. The last known leap-second is used over any future interval.

NOTE: "n.a." in output means quantity "not available" at the print-time.

R.A._(ICRF/J2000.0)_DEC = J2000.0 astrometric right ascension and declination of target center. Adjusted for light-time. Units: HMS (HH MM SS.ff) and DMS (DD MM SS.f)

APmag S-brt = Target's approximate apparent visual magnitude & surface brightness. For planets and satellites, values are available only for solar phase angles in the range generally visible from Earth. This is to avoid extrapolation of models beyond their valid (data-based) limits. Units: MAGNITUDE & VISUAL MAGNITUDES PER SQUARE ARCSECOND

delta deldot = Range ("delta") and range-rate ("delta-dot") of target center with respect to the observer at the instant light seen by the observer at print-time would have left the target center (print-time minus down-leg light-time); the distance traveled by a light ray emanating from the center of the target and recorded by the observer at print-time. "deldot" is a projection of the velocity vector along this ray, the light-time-corrected line-of-sight from the coordinate center, and indicates relative motion. A positive "deldot" means the target center is moving away from the observer (coordinate center). A negative "deldot" means the target center is moving toward the observer. Units: AU and KM/S

S-O-T /r = Sun-Observer-Target angle; target's apparent solar elongation seen from observer location at print-time. If negative, the target center is behind the Sun. Angular units: DEGREES.

The '/r' column is a Sun-relative code, output for observing sites with defined rotation models only.

/T indicates target trails Sun (evening sky)
/L indicates target leads Sun (morning sky)

NOTE: The S-O-T solar elongation angle is the total separation in any direction. It does not indicate the angle of Sun leading or trailing.

S-T-O = "S-T-O" is the Sun->Target->Observer angle; the interior vertex angle at target center formed by a vector to the apparent center of the Sun at reflection time on the target and the apparent vector 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


Computations by ...
Solar System Dynamics Group, Horizons On-Line Ephemeris System
4800 Oak Grove Drive, Jet Propulsion Laboratory
Pasadena, CA 91109 USA
Information: http://ssd.jpl.nasa.gov/
Connect : telnet://ssd.jpl.nasa.gov:6775 (via browser)
telnet ssd.jpl.nasa.gov 6775 (via command-line)
Author : Jon.Giorgini@jpl.nasa.gov

About Space College

  Space News and Other Sites