"Pseudo-MPEC" for 2018-103B = NORAD 43846 = Chang'e 4 booster

Created 2019 Mar 31 14:23:36 UT using Find_Orb

Click here for an explanation of pseudo-MPECs

TLEs are available for this object. (Currently running to July 2019. By then, we'll probably get more observations.) Space-Track had TLEs for this object, but they involved the object being in low-earth orbit and were essentially works of fiction.

You can click here to generate ephemerides for a particular place and time span. Enter the "object name" as "Old A10azqL" (the name under which the object was first found) and set the rest of the ephemeris quantities as you wish.

Jost Jahn was able to image this object in mid-March from (C95) ROTAT (click here for a timelapse video), with further data the next day from Masayaki Suzuki at (U69). Jost saw a possible light-curve of about 20 minutes, which would be unusually long for an empty booster. At the following perigee on March 30, Jost again got data on the object, and CSS swept it up the next day in the course of routine asteroid surveying. So the orbit is quite well-determined at this point.

With the new data, the effects of solar radiation pressure are now noticeable; we have a reasonably well-determined area/mass ratio and can say something about where the object will be over the coming year with a decent degree of confidence. The object is doing a good job of staying away from the moon; it gets within about 85000 km on 2019 April 26, which will raise its perigee from about 100000 km to about 150000 km, increasing the orbital period from about 18 days to about 22 days. Unfortunately, I don't see it hitting the earth or moon in the next few years. (But it is an artsat, in a somewhat chaotic orbit.)

My initial orbit for this object was based on the first four observations (the ones made as the object was still going toward the moon) plus the knowledge that it had been near a perigee of about 200 km a little after launch time. This resulted in something close to a wild guess, though probably good enough over the short term that somebody could have observed the object if they had wanted to. It was the best I could do at the time; the Chinese space agency is very close-mouthed about where things are going.

In hindsight, my "guess" gave a perilune that was off by about two hours and a prograde pass; the actual lunar flyby was retrograde. As a result, the object ended up in a lower orbit than I expected (period of about 16 days, not 37). The orbital period has since increased by a couple of days due to lunar and solar perturbations.

 
 Astrometry: 
     A10azqL  C2018 12 09wwFKw3Astrometry4fV(7Z8MXi:i4cZ`CX#F](UfRdW;hk[xMrY?T05
     A10azqL  C2018 12 09k.:ZwWn]!Ma!dCVPw.nx?0fdkd7Credacted;Wr5?fICrDy;Fc^9T05
     A10azqL  C2018 12 09[ebY*ryI=`5aq-PksT-=La;Kah:'v]i/A;cj3'+HB0MG)[/-p2MWT05
     A10azqL  C2018 12 09gu[=X%'tDDaKO0G,@NS#/bXpYt(`Q\''rE9Qm%J8gOgQvsKK'NZiT05
     A10aHKA  C2018 12 15,QZ3bfJjmvi,MI,slsHYJx-u#4$8W0CZEVv1Z@clickXVcd]2j+0T08
     A10aHKA  C2018 12 15c-Dh`+ccshereg!PRxdQ/;bi[@E^]1W'=gE$e3dJvNC)NJ(l!7-=T08
     A10aHKA  C2018 12 15ZC7ZBurSRyJtDO9forW9d.Aaexplanation%iP-\+xCX@9mb4epAT08
     A10aHKA  C2018 12 15d@ocI.@=L(84.=#8$9wV7y5W8\t'GDeqNhYI_,Qwt:;w,?k^P(7eT08
2018-103B     CK181217:02295858 227.70806   +27.89912            15.1 GV     J95
2018-103B     CK181217:02470636 228.77451   +27.73545            14.3 GV     J95
2018-103B     CK181217:02501379 228.96439   +27.70528            14.8 GV     J95
2018-103B     CK181217:02562616 229.33760   +27.64495            14.0 GV     J95
2018-103B    KC2019 03 15.07503918 11 41.88 +09 12 14.7          16.3 GV     C95
2018-103B    KC2019 03 15.07735618 11 45.07 +09 11 24.7          15.5 GV     C95
2018-103B    KC2019 03 15.07968018 11 48.31 +09 10 34.8          16.6 GV     C95
2018-103B    KC2019 03 15.08206718 11 51.72 +09 09 40.6          16.2 GV     C95
2018-103B    KC2019 03 16.12443718 38 54.47 +02 59 53.6          15.7 GV     C95
2018-103B    KC2019 03 16.13186918 39 00.38 +02 57 36.7          16.1 GV     C95
2018-103B    KC2019 03 16.13558918 39 03.28 +02 56 28.1          16.2 GV     C95
2018-103B    KC2019 03 16.13930518 39 06.21 +02 55 19.9          15.6 GV     C95
2018-103B    KC2019 03 16.52792 18 47 26.67 +01 01 21.9          16.3 GV     U69
2018-103B    KC2019 03 16.53444 18 47 29.55 +00 59 26.6          17.0 GV     U69
2018-103B    KC2019 03 29.80372506 45 42.16 -01 00 26.3          13.4 GV     C95
2018-103B    KC2019 03 29.80581506 46 15.63 -00 51 50.5          13.3 GV     C95
2018-103B    KC2019 03 29.80790506 46 48.97 -00 43 17.3          13.8 GV     C95
2018-103B    KC2019 03 29.80999206 47 22.33 -00 34 44.1          15.6 GV     C95
     C069NX1  C2019 03 31.41877 15 13 24.91 +34 05 16.6          13.8 GV     703
     C069NX1  C2019 03 31.42945 15 14 32.42 +33 56 18.4          14.0 GV     703

Station data:
(703) Catalina Sky Survey  (N32.417006 W110.732640)  US/Arizona.  Observer R.
   A. Kowalski. Measurers B. M. Africano, E. J. Christensen, G. A. Farneth,
   D. C. Fuls, A. R. Gibbs, A. D. Grauer, H. Groeller, R. A. Kowalski, S. M.
   Larson, G. J. Leonard, T. A. Pruyne, R. L. Seaman, F. C. Shelly. 0.68-m
   Schmidt + 10K CCD.
(C95) SATINO Remote Observatory, Haute Provence  (N43.932042 E5.712390)
   France.  Observer J. Jahn. 0.60-m f/3.2 Newtonian reflector + CCD.
(J95) Great Shefford  (N51.474969 W1.447003)  UK.  Observer P. Birtwhistle.
(T05) ATLAS-HKO, Haleakala  (N20.707582 W156.257008)  US/Hawaii.  Observers
   L. Denneau, A. Heinze, H. Weiland, J. Tonry, H. Flewelling, A.
   Fitzsimmons, D. Young, B. Stalder. Measurers L. Denneau, A. Heinze, J.
   Tonry. 0.5-m f/2.0 Schmidt + CCD.
(T08) ATLAS-MLO, Mauna Loa  (N19.535772 W155.576400)  US/Hawaii.  Observers
   L. Denneau, A. Heinze, H. Weiland, J. Tonry, H. Flewelling, A.
   Fitzsimmons, D. Young, B. Stalder. Measurers L. Denneau, A. Heinze, J.
   Tonry. 0.5-m f/2.0 Schmidt + CCD.
(U69) iTelescope SRO Observatory, Auberry  (N37.070390 W119.413000)
   US/California.  Observer M. Suzuki. 0.61-m f/6.5 reflector + CCD.

Orbital elements:  2018-103B = NORAD 43846 = Chang'e 4 booster
   Perigee 2019 Mar 11.427068 +/- 1.68e-5 TT = 10:14:58 (JD 2458553.927068)
Epoch 2019 Mar 15.0 TT; AMR 0.01119 +/- 7.49e-5 m2/kg        Gray
M  70.82912061 +/- 0.00027          (J2000 equator)
n  19.82381095 +/- 1.77e-5          Peri.   21.32271 +/- 0.00017
a291840.397 +/- 0.173               Node   103.11176 +/- 0.000052
e   0.6631159 +/- 5.11e-7           Incl.   42.62140 +/- 0.000034
P  18.16d                  H 25.9   G  0.15   U  5.4
q 98316.3714 +/- 0.157    Q 485364.423 +/- 0.333
From 28 observations 2018 Dec. 9-2019 Mar. 31; mean residual 1".796
Orbital elements (near launch):  2018-103B = NORAD 43846 = Chang'e 4 booster
   Perigee 2018 Dec 7.777670 +/- 4.63e-5 TT = 18:39:50 (JD 2458460.277670)
Epoch 2018 Dec  7.8 TT = JDT 2458460.3                        Gray
M   0.695783308 +/- 0.0014          (J2000 equator)
n  31.159821357 +/- 0.000411        Peri.  146.358925 +/- 0.0014
a215877.2448 +/- 1.9                Node   354.247304 +/- 0.0016
e   0.96911543 +/- 6.3e-7           Incl.   28.475953 +/- 0.00052
P  11.55d                  H 25.5   G  0.15   U  7.5
q 6667.274145 +/- 0.0897    Q 425087.2155 +/- 3.85
From 12 observations 2018 Dec. 9-17; mean residual 0".341

Orbital elements (lunar flyby):  2018-103B = NORAD 43846 = Chang'e 4 booster
   Perilune 2018 Dec 12.411109 +/- 1.25e-5 TT =  9:51:59 (JD 2458464.911109)
Epoch 2018 Dec 12.4 TT = JDT 2458464.9                        Gray
q  7996.894294 +/- 0.181            (J2000 ecliptic)
H   25.5  G 0.15                    Peri.  104.122563 +/- 0.00037
                                    Node    47.037481 +/- 0.0007
e   2.01955854 +/- 1.8e-5           Incl.  153.987854 +/- 0.00041
From 12 observations 2018 Dec. 9-17; mean residual 0".341
Residuals in arcseconds: 
181209 T05 .030- .032+    181217 J95 .301- .231+    190316 U69 .934- .186-
181209 T05 .122+ .764-    181217 J95 .875+ .032-    190316 U69 .078- .572-
181209 T05 .231- .267+    190315 C95 .088- .371-    190329 C95 4.70- 4.71-
181209 T05 .095- .155+    190315 C95 .491- .263-    190329 C95 2.85- 2.88-
181215 T08 .564- .493+    190315 C95 .258+ .117+    190329 C95 3.91- 4.12-
181215 T08 .610- .396+    190315 C95 2.82+ 2.42-    190329 C95 4.91- 5.07-
181215 T08 1.03- .627+    190316 C95 .765+ 1.15+    190331 703 1.09+ 1.38-
181215 T08 .913- .359+    190316 C95 .840- .986+    190331 703 1.93+ 1.62-
181217 J95 .822+ .066-    190316 C95 .912- .858+
181217 J95 .528- .163+    190316 C95 .556+ 1.08+

Ephemerides (geocentric):
Date (UTC)   RA              Dec         delta  elong  mag " sig PA
---- -- --  -------------   -----------  ------ -----  --- ---- ---
2019 03 30  07 53 33.664   +14 28 33.46  111317 108.7 12.7 .953  53
2019 03 31  13 52 08.019   +39 08 45.26  164738 133.5 12.9 .170  50
2019 04 01  16 19 00.460   +26 35 56.36  243486 118.7 14.1 .401 105
2019 04 02  17 20 40.494   +16 38 21.97  310780 108.2 15.0 .454 116
2019 04 03  17 57 57.226   +09 22 20.48  365090 101.1 15.6 .467 121
2019 04 04  18 25 11.677   +03 39 43.52  407837  95.9 16.0 .470 125
2019 04 05  18 47 25.528   -01 07 03.79  440298  91.7 16.3 .469 127
2019 04 06  19 06 57.943   -05 19 10.27  463392  88.3 16.6 .468 128
2019 04 07  19 25 07.931   -09 09 38.89  477735  85.2 16.8 .467 129
2019 04 08  19 42 49.975   -12 47 23.17  483702  82.4 17.0 .468 130
2019 04 09  20 00 50.260   -16 19 06.44  481460  79.7 17.1 .470 130
2019 04 10  20 19 57.197   -19 50 28.60  470984  76.9 17.2 .475 130
2019 04 11  20 41 12.400   -23 26 47.24  452047  74.1 17.2 .485 129
2019 04 12  21 06 08.173   -27 13 19.16  424180  70.9 17.3 .502 128
2019 04 13  21 37 23.765   -31 14 57.57  386610  67.2 17.3 .531 125
2019 04 14  22 20 14.897   -35 32 37.58  338158  62.7 17.3 .589 120
2019 04 15  23 26 47.633   -39 42 23.96  277164  57.0 17?? .718 110
2019 04 16  01 27 43.761   -40 39 43.51  202171  50.5 17?? 1.10  88
2019 04 17  05 14 47.221   -17 52 40.39  122466  60.4 15.3 2.69  54
2019 04 18  11 29 00.259   +39 50 44.37  126148 120.9 12.7 3.06  76
2019 04 19  15 40 01.570   +31 52 05.61  206763 129.2 13.5 1.56 114
2019 04 20  17 03 02.309   +19 49 11.69  280759 123.1 14.3 1.11 122
2019 04 21  17 46 36.819   +11 20 57.87  340258 117.6 14.9 .918 125
2019 04 22  18 16 21.953   +04 54 18.59  386662 113.3 15.3 .822 127
2019 04 23  18 39 43.038   -00 24 14.84  421461 109.8 15.6 .766 128
2019 04 24  18 59 42.361   -05 04 17.16  445603 106.8 15.8 .731 128
2019 04 25  19 17 54.868   -09 25 52.66  459436 104.2 16.0 .707 128
2019 04 26  19 35 33.639   -13 48 07.73  462424 101.7 16.1 .689 129
2019 04 27  19 54 43.687   -18 27 25.95  453418  99.1 16.1 .702 131
2019 04 28  20 17 59.155   -23 22 11.93  433576  95.8 16.2 .779 130
2019 04 29  20 47 20.357   -28 31 03.29  404647  91.6 16.2 .928 126
2019 04 30  21 26 26.688   -33 55 54.55  367000  86.2 16.2 1.18 120
2019 05 01  22 23 10.594   -39 23 36.38  320522  79.1 16.2 1.64 111
2019 05 02  23 53 59.094   -43 29 08.29  265532  69.2 16.4 2.52  95
2019 05 03  02 20 47.257   -40 02 28.04  205264  55.6 16?? 4.41  70
2019 05 04  05 25 11.024   -13 57 54.04  156053  50.0 16?? 7.77  47
2019 05 05  08 46 33.211   +29 05 56.02  158603  82.4 14.6 7.37  55
2019 05 06  12 27 39.228   +43 52 59.19  209813 111.6 14.1 3.96  91
2019 05 07  14 45 11.995   +38 11 56.52  269887 125.2 14.2 2.19 116
2019 05 08  15 57 18.599   +29 56 59.04  324527 131.0 14.4 1.35 128
2019 05 09  16 41 48.975   +22 33 40.84  371165 133.3 14.7 .908 136
2019 05 10  17 13 37.664   +16 10 02.76  409799 133.9 14.9 .647 141
2019 05 11  17 38 47.825   +10 31 48.41  440896 133.5 15.0 .481 146
2019 05 12  18 00 12.684   +05 25 52.07  464929 132.7 15.2 .370 151
2019 05 13  18 19 28.247   +00 42 18.75  482261 131.4 15.3 .294 155
2019 05 14  18 37 35.841   -03 46 21.45  493140 129.8 15.4 .241 159
2019 05 15  18 55 20.968   -08 06 05.27  497694 128.0 15.4 .206 162
2019 05 16  19 13 23.509   -12 21 55.41  495945 125.8 15.5 .183 163
2019 05 17  19 32 25.092   -16 38 28.56  487814 123.2 15.5 .170 162
2019 05 18  19 53 16.904   -21 00 14.05  473121 120.2 15.6 .169 158
2019 05 19  20 17 11.285   -25 31 39.47  451590 116.6 15.6 .182 150
2019 05 20  20 46 03.075   -30 16 42.23  422844 112.2 15.6 .215 140
2019 05 21  21 23 14.281   -35 16 27.03  386428 106.5 15.6 .282 128
2019 05 22  22 15 13.784   -40 19 40.46  341894  98.9 15.5 .406 115
2019 05 23  23 34 54.254   -44 25 29.73  289133  88.1 15.6 .643  98
2019 05 24  01 41 26.409   -43 25 16.83  229752  71.6 15.9 1.13  74
2019 05 25  04 29 35.264   -25 38 17.36  173181  46.8 17?? 2.08  49
2019 05 26  07 31 22.107   +16 14 38.94  152605  48.0 16?? 2.54  45
2019 05 27  11 14 10.827   +43 45 27.64  190769  85.9 14.8 1.32  78
2019 05 28  14 08 57.879   +41 58 00.56  250717 110.1 14.5 .510 115