"Pseudo-MPEC" for ExoMars2a = booster + spacecraft

Created 2016 Mar 17 13:04:58 UT using Find_Orb

This is astrometry for the ExoMars mission before going to heliocentric orbit. (467) and (Q64) tracked two objects in elliptical orbits, which I'm calling ExoMars1a and ExoMars2a. One of them is the combined ExoMars probe and booster that accelerated it into heliocentric orbit, and the other is a discarded fuel tank. But NORAD has now provided TLEs (two-line elements) for the fuel tank, which has received the designation 2016-017C = NORAD 41390. That TLE gives positions within 0.04 degrees of ExoMars1, and more than 0.20 degrees from ExoMars2. So most likely, ExoMars1 is the fuel tank (which is the way I currently have things labelled). This seems really likely, though not 100% certain.

The astrometry for ExoMars1a and ExoMars2a is better than it may seem. The problem is that the times for the (467) observations were recorded to the nearest second, and the objects were moving at about 21 arcseconds per second. So simply rounding the time to the nearest second could introduce up to 10.5 seconds of error. The "cross-track" residuals are all under half an arcsecond, bolstering the conclusion that we're really just seeing timing error here.

After the ExoMars spacecraft and booster accelerated and left the Earth/Moon system for Mars, they were also tracked, and links are provided to the data for those objects below.

Astrometry:
ExoMars2a    TC2016 03 14.72567718 10 55.687-49 14 27.17         11.5 R      467
ExoMars2a    TC2016 03 14.72592018 11 36.471-49 10 35.02         11.6 R      467
ExoMars2a    TC2016 03 14.72627918 12 36.699-49 04 49.40         11.5 R      467
ExoMars2a    tC2016 03 14.72628918 44 55.903-47 24 25.54         11.3 R      Q64
ExoMars2a    tC2016 03 14.72648718 45 26.718-47 21 06.83         11.3 R      Q64
ExoMars2a    TC2016 03 14.72677718 13 59.485-48 56 49.49         11.4 R      467
ExoMars2a    TC2016 03 14.72737818 15 39.699-48 47 00.48         11.5 R      467
ExoMars2a    TC2016 03 14.72837418 18 25.047-48 30 29.20         12.9 R      467
ExoMars2a    TC2016 03 14.73467018 35 43.908-46 37 16.93         11.9 R      467
ExoMars2a    TC2016 03 14.73578118 38 44.759-46 15 50.10         11.5 R      467
ExoMars2a    TC2016 03 14.73793418 44 36.473-45 32 32.32         11.4 R      467
ExoMars2a    TC2016 03 14.73954318 48 59.147-44 58 49.83         11.4 R      467
ExoMars2a    TC2016 03 14.74145318 54 08.442-44 17 34.62         10.9 R      467
ExoMars2a    TC2016 03 14.74258718 57 12.917-43 52 08.87         11.5 R      467

Station data:
(467) Auckland Observatory (S36.9079 E174.7766)  New Zealand.   Observer G. W.
    Christie.  Measurers M. Micheli, G. W. Christie, K. Merz, D. Koschny.
    0.40-m f/10 Schmidt-Cassegrain + CCD.
(Q64) Siding Spring-LCOGT B (S31.27307 E149.07078)  Australia/NSW.   Observers
    A. Tripp, S. Roberts.  Measurers M. Micheli, A. Tripp, K. Merz, D. Koschny.
     1.0-m f/8 Ritchey-Chretien + CCD.

Orbital elements:  ExoMars2a = booster + spacecraft
   Perigee 2016 Mar 15.092507 +/- 0.000531 TT =  2:13:12 (JD 2457462.592507)
Epoch 2016 Mar 15.0 TT = JDT 2457462.5                        Find_Orb
M 232.832057 +/- 0.8                (J2000 equatorial)
n1374.678998696 +/- 1.33            Peri.   99.502374 +/- 0.28
a 17290.30446 +/- 11.2              Node   323.771407 +/- 0.048
e   0.58994151 +/- 0.00221          Incl.   51.540987 +/- 0.028
P 377.10m                  H 27.7   G  0.15   U 12.9
q 7090.036106 +/- 34.8    Q 27490.57282 +/- 52.9
From 14 observations 2016 Mar. 14 (24.4 min); mean residual 6".255
Residuals in arcseconds: 
160314 467 9.77+ 5.62+    160314 467 7.16+ 4.12+    160314 467 1.59+ 1.34+
160314 467 10.4+ 5.94+    160314 467 6.36+ 3.78+    160314 467 8.37+ 6.20+
160314 467 11.7+ 6.83+    160314 467 1.76+ 1.58+    160314 467 5.92- 4.59-
160314 Q64 9.04- 5.65-    160314 467 7.99+ 5.67+    160314 467 4.21- 3.34-
160314 Q64 8.35- 5.46-    160314 467 1.61- 1.40-

Ephemerides (geocentric):
Date (UTC) HH   RA              Dec         delta   r     elong  mag " sig PA
---- -- -- --  ------------   ------------  ------ ------ -----  --- ---- ---
2016 03 14 00  20 16 30.927   -23 24 34.10   18075 0.9942  52.7 13?? 3382  41
2016 03 14 01  02 51 07.131   +50 58 03.74    7198 0.9942  67.5 10.4 528'  81
2016 03 14 02  11 38 28.132   -32 33 52.51   16865 0.9943 144.9  9.4 5463 134
2016 03 14 03  14 06 04.133   -49 17 29.30   24503 0.9943 119.1 10.9 1905 110
2016 03 14 04  16 11 48.993   -51 12 33.67   27406 0.9943 101.2 11.8  985  85
2016 03 14 05  18 00 24.483   -45 32 14.75   26194 0.9943  84.2 12.3  804  62
2016 03 14 06  19 43 05.375   -30 52 33.64   20612 0.9942  62.1 13.1 1653  44
2016 03 14 07  22 38 34.783   +18 37 39.04    9795 0.9943  25.6 16?? 213'  40
2016 03 14 08  10 44 52.341   -20 25 00.52   13647 0.9944 153.8 Sha  7272 140
2016 03 14 09  13 26 52.858   -46 47 01.85   22858 0.9944 125.3 10.6 1913 118
2016 03 14 10  15 37 52.859   -51 32 27.88   27007 0.9944 106.2 11.6  772  93
2016 03 14 11  17 30 52.716   -47 50 14.38   26958 0.9944  89.5 12.2  407  69
2016 03 14 12  19 12 42.316   -36 23 34.05   22701 0.9943  69.8 12.8  656  47
2016 03 14 13  21 21 04.515   -04 41 14.28   13355 0.9943  34.4 15?? 4231  37
2016 03 14 14  09 30 29.490   +01 37 11.07   10091 0.9944 148.0 Sha  182' 142
2016 03 14 15  12 45 46.766   -42 53 25.72   20805 0.9945 132.4 10.2 1969 125
2016 03 14 16  15 02 26.543   -51 14 55.42   26271 0.9945 111.3 11.3  583 103
2016 03 14 17  17 00 23.748   -49 34 17.61   27385 0.9944  94.5 12.0   90  86
2016 03 14 18  18 43 38.769   -40 38 29.46   24379 0.9944  76.4 12.6   31 170
2016 03 14 19  20 34 45.474   -18 16 00.41   16612 0.9944  48.0 13?? 1135  36
2016 03 14 20  06 36 23.841   +41 31 27.65    7299 0.9945 102.1 Sha  255' 124
2016 03 14 21  12 01 49.879   -36 56 33.53   18307 0.9946 140.5  9.7 2070 132
2016 03 14 22  14 25 29.019   -50 13 36.84   25188 0.9946 116.8 11.1  401 114
2016 03 14 23  16 28 40.661   -50 46 12.94   27481 0.9945  99.5 11.8  186  70