Observable CONTOUR maneuvers, July 27&31, &Aug03

From: Tony Beresford (aberesford@iprimus.com.au)
Date: Fri Jul 26 2002 - 13:44:25 EDT

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    This message  was sent from David Dunham of Occultation fame
    to  the the Minor Planet mailing list. 
    To add to David's remarks CONTOUR is on the JPL HORIZONS ephemeris
    calculator, and can be used to generate predictions.
    OIG also has TLEs for this object ( 27457 )
    With list members interested in observing rocket firings,
    They may want to take a look. You will probably need
    better optical aid than 7x50 binocs though.
    1 27457U 02034A   02199.75000000 +.00000000 +00000-0 +00000-0 0 00134
    2 27457 030.1915 192.4247 8916057 337.7130 001.6441 00.58031961000004
    Tony Beresford
    -------- Original Message --------
    Subject: Observable CONTOUR maneuvers, July 27&31, &Aug03
    Date: Fri, 26 Jul 2002 02:18:37 -0400
    On July 27, July 31, and August 3, the CONTOUR spacecraft will
    perform delta-V maneuvers at high altitude that might be observed
    from large areas of the dark side of the Earth.  CONTOUR was
    launched on July 3rd into a 1.75-day-period Earth orbit that extends
    about 18 Earth radii, or almost a third of the way to the Moon, at
    apogee.  On August 15, at 8:46 U.T., a solid rocket motor (SRM) in
    the center of CONTOUR will blast the spacecraft out of Earth orbit
    into a high-energy heliocentric trajectory that will make a distant
    Earth flyby a year later, then go on to encounter Comet Encke in
    November 2003.  More Earth swingbys and comet encounters will occur
    after that.  But for now, there are three good opportunities to
    observe the spacecraft while it is relatively close to the Earth.
    The SRM burn would be quite spectacular, but it will be performed at
    perigee in daylight over the Indian Ocean, too far from the nearest
    island to be seen.  Previous CONTOUR delta-V maneuvers, called Orbit
    Correction Maneuvers (OCM's), have been performed at perigee in
    daylight, so they, too, were not observable.
    In summary, the three upcoming maneuvers are as follows:
    OCM6, a 58.5-second burn on July 27 centered at UTC 12h 02m 28.9s,
      45,445 km over long. 162.42 deg. W., lat. 23.77 deg. N., visible
      from much of the Pacific Ocean, especially Hawaii, and also from
      Japan and other countries of the western Pacific, including
      Australia and New Zealand.
    OCM7, a 63.2-second burn on July 31 centered at UTC 17h 13m 09.9s,
      108505 km over long. 146.91 deg. E., lat. 9.64 deg. N., visible
      from Japan, New Zealand, Australia, and most of Asia.
    OCM8, a 17.8-second burn on August 3 centered at UTC 07h 15m 55.4s,
      12021 km over long. 138.49 deg. W., lat. 30.53 deg. N., visible
      from Hawaii and most of North America, especially the western part.
    I don't know how bright these burns will appear; I hope that some
    observations of the July 27th maneuver can be made, especially
    video observations with sensitive cameras like the Watec 902H or
    Supercircuits PC164C.  I think the CONTOUR spacecraft itself, which
    is always in sunlight, will be only 10th to 12th mag.; it is
    cylindrical, about 1.7 meters high and across, covered mainly with
    solar cells.  But it doesn't have large panels pointed towards the
    Earth like NEAR.  The burns, with two 5-pound hydrazine thrusters,
    should be a few magnitudes brighter, but just how many, I don't
    know; maybe someone else with experience observing spacecraft
    maneuvers can give a good estimate.  I will be interested in any
    observations, especially video, that might be made of these
    In addition to the delta-V maneuvers, there are smaller attitude
    maneuvers, called ACM's, performed in pulse mode with pairs of 0.2-
    pound thrusters that will be a few magnitudes fainter than the
    OCM's.  Two ACM's are planned on July 29 starting at 10h 00m U.T.;
    they last typically an hour; I'll provide more information about
    them in my next message.
    Earth-centered J2000 equatorial coordinates, and orbital elements,
    of CONTOUR at the central time of the OCM's are given below for
    calculating local predictions (R.A. and Dec., and altitude and
    azimuth).  I will try to generate some local predictions for OCM6
    later today, and post them on my Web site at http://iota.jhuapl.edu
    I think local (topocentric) predictions can also be computed at the
    JPL Horizons ephemeris Web site; if they don't have CONTOUR in their
    data now, I'll ask to see if it can be added later today.  Note that
    the data below for OCM6 should be quite accurate, but the times and
    locations of the later maneuvers will change a little due to
    maneuver execution errors and the slightly variable effects of
    atmospheric drag at the perigees.  Closer to the times of the later
    maneuvers, better predictions will be possible.
    David Dunham, IOTA and CONTOUR Mission Design Team
    Name: OCM6 d-omega dV 148 (performed at true anomaly 148.5 deg.,
      it primarily targets the desired argument of perigee for the
      Aug. 15th SRM burn).
      UTC Gregorian Date: 27 Jul 2002 12:02:28.8681 UTC (center)
    State Vector in Coordinate System: Earth Centered Mean J2000
    Parameter Set Type:  Cartesian
      X:  37963.979593083197 km  Vx:  2.8493191365850223 km/sec
      Y: -28435.991238763087 km  Vy: -0.5374509666709674 km/sec
      Z:  20865.402121262068 km  Vz:  0.6408573138008424 km/sec
    Parameter Set Type:  Keplerian orbital elements
      sma: 60705.896102872473 km  RAAN:  191.285999418392 deg
      ecc:     0.891697629886        w:  339.2040580312204 deg
      inc:    30.575511654913 deg   TA:  148.4622322180457 deg
    Parameter Set Type:  Spherical
      Right Asc:   323.1658509431595 deg
           Decl:    23.74440950155947 deg
            |R|: 51819.2469065019830000 km
    Name: OCM7 d-inc. & per. lower (performed near apogee, it primarily
      targets the desired inclination and perigee height for the Aug.
      15th SRM burn).
    UTC Gregorian Date: 31 Jul 2002 17:13:09.9323  UTC (center)
    Parameter Set Type:  Cartesian
       X: 112710.401947623670 km  Vx:  0.0171005619124146 km/sec
       Y: -11198.368256937616 km  Vy:  0.5372407489732711 km/sec
       Z:  19208.226547974984 km  Vz: -0.3090896893056189 km/sec
    Parameter Set Type:  Keplerian
      sma: 60834.74169497374500 km  RAAN:  190.8895025415419 deg
      ecc:     0.89078192258006        w:  339.9109821717473 deg
      inc:    30.74739392798233 deg   TA:  180.9999998190316 deg
    Parameter Set Type:  Spherical
      Right Asc:    354.3259858489416 deg
           Decl:      9.624994428804927 deg
            |R|: 114882.5231527024200000 km
    Name: OCM8 d-bigomega dV (performed at true anomaly 111 deg., it
      primarily targets the desired right ascension of the ascending node
      (RAAN) for the Aug. 15th SMR burn).
    UTC Gregorian Date: 3 Aug 2002 07:15:55.3766  UTC (center)
    State Vector in Coordinate System: Earth Centered Mean J2000
    Parameter Set Type:  Cartesian
       X:   3342.1306032929920 km  Vx:  4.6119034678273367 km/sec
       Y: -15496.8063750805030 km  Vy: -3.1684260664246771 km/sec
       Z:   9327.7251006836759 km  Vz:  2.3403850779209407 km/sec
    Parameter Set Type:  Keplerian
       sma: 60808.12340468973700 km  RAAN:  190.8002487426286 deg
       ecc:     0.891130110024153       w:  340.1808183792037 deg
       inc:    30.47907158998058 deg   TA:  111.0000000021569 deg
    Parameter Set Type:  Spherical
      Right Asc:   282.1703353369059 deg
           Decl:    30.47191068517976 deg
            |R|: 18393.6755530298430000 km
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