"Pseudo-MPEC" for 2020-049A = NORAD 45935 = Tianwen-1 spacecraft
Created 2020 Aug 4 21:45:23 UT using Find_Orb
Click here for an explanation of pseudo-MPECs
We also have data for the booster for this spacecraft. At first, we weren't sure which object was the spacecraft and which was the booster. However, Masayaki Suzuki and Peter Birtwhistle both report seeing significant light variations for TianweB (period about 40-50 seconds), which is what you'd get with a tumbling rocket booster; a spacecraft maintaining its orientation with respect to Earth would be more stable. Meanwhile, TianweA shows almost no variation in brightness. Edgar Kaiser and others report receiving transmissions from Tianwen-1. So we're confident TianweA is the spacecraft, TianweB the booster.
Both objects should continue to be observable for a while, possibly to the end of July, and they've been observed a bit by the amateur radio community; it's possible that we can figure out a match between the frequency shifts they detect as Doppler data and the radial velocities computed using the astrometry.
It's been mentioned that the Mars flyby distance is somewhat high (about three million kilometers). It's normal for a mid-course correction or two to be made. This one will be a little on the large side, but not unreasonably so. Quanzhi Ye has pointed out that one mid-course maneuver is planned (third slide; text above '2020/10/5' reads "Deep Space Maneuver".)
And, in fact, you'll see that the last few observations (from early August) show residuals of over an arcminute. The object has definitely maneuvered.
Updates for both objects will be posted from time to time as I receive more data.
Astrometry:
A10oyFM* C2020 07 23[tc,2(5+9Astrometryg^Yd)1U8@Aredacted;KRnV/wp:WF(b[KT08
A10oyFM C2020 07 23ghSVclicksGDXZbaherekqS18X=,4M]^Afor:^Iexplanation?%T08
A10oyFM C2020 07 23'an[=g\;yW`-NmrfL6L:=/S^I7b%1g-L[BC#$9tp=[E0-e6w8Q:!T08
A10oyFM C2020 07 23*SKu;P`\]2rY0O]IQ1sHFr3T^I+PQ^SV4Hat^xaVXq+ot7'm_'frT08
Probe2 CK200723:2342430 011.46081 +14.40392 15.5 GV Z80
Probe2 CK200723:2344230 011.46280 +14.40863 15.5 GV Z80
Probe2 CK200723:2346031 011.46494 +14.41339 15.6 GV Z80
TianweA KC2020 07 24.06585200 47 39.000+15 01 43.61 15.6 G J04
TianweA KC2020 07 24.06818000 47 38.692+15 02 12.93 15.4 G J04
TianweA KC2020 07 24.07051300 47 38.336+15 02 41.92 15.5 G J04
Tianwen-1 C2020 07 24.09738 00 46 31.26 +14 59 59.3 15.7 GV I89
Tianwen-1 C2020 07 24.10042 00 46 29.86 +15 00 30.6 15.9 GV I89
Tianwen-1 C2020 07 24.10354 00 46 28.40 +15 01 02.1 15.7 GV I89
Tianwen-1 C2020 07 24.10762 00 46 26.39 +15 01 42.7 15.9 GV I89
TianweA KC2020 07 24.10797700 47 26.719+15 09 57.63 15.5 G J04
TianweA KC2020 07 24.20525300 46 22.833+15 23 49.05 15.7 G J04
TianweA KC2020 07 24.20757100 46 21.033+15 24 03.50 15.7 G J04
TianweA KC2020 07 25.04562100 52 21.072+15 56 01.86 16.8 G Z84
TianweA KC2020 07 25.04939800 52 20.133+15 56 17.99 16.8 G Z84
TianweA KC2020 07 25.05317400 52 19.146+15 56 33.92 16.8 G Z84
TianweA KC2020 07 25.05695400 52 18.106+15 56 49.60 16.8 G Z84
TianweA KC2020 07 25.06407 00 51 50.73 +15 53 50.9 17.0 G 204
TianweA KC2020 07 25.06650 00 51 49.94 +15 53 59.2 17.0 G 204
TianweA KC2020 07 25.06893 00 51 49.14 +15 54 07.7 17.0 G 204
TianweA KC2020 07 25.07136 00 51 48.34 +15 54 15.9 17.0 G 204
TianweA KC2020 07 25.07380 00 51 47.51 +15 54 24.0 17.0 G 204
TianweA KC2020 07 25.07776 00 51 46.14 +15 54 37.0 17.1 G 204
TianweA KC2020 07 25.08020 00 51 45.29 +15 54 45.0 17.0 G 204
TianweA KC2020 07 25.08263 00 51 44.42 +15 54 52.7 17.1 G 204
TianweA KC2020 07 25.08506 00 51 43.55 +15 55 00.4 17.1 G 204
TianweA KC2020 07 25.08749 00 51 42.66 +15 55 07.9 17.1 G 204
TianweA KC2020 07 25.12635200 51 51.799+16 00 56.29 16.9 G Z84
TianweA KC2020 07 25.12909100 51 50.547+16 01 04.30 17.0 G Z84
TianweA KC2020 07 25.13184200 51 49.274+16 01 12.13 17.0 G Z84
TianweA KC2020 07 25.13459400 51 47.990+16 01 19.89 17.0 G Z84
TianweA KC2020 07 25.18418200 51 23.639+16 03 14.37 16.8 G Z84
Tianwen1 C2020 07 25.44727 00 52 28.46 +16 07 18.0 16.9 718
Tianwen1 C2020 07 25.44766 00 52 28.30 +16 07 18.1 16.8 718
Tianwen1 C2020 07 25.44883 00 52 27.80 +16 07 21.0 16.8 718
Tianwen1 C2020 07 25.44922 00 52 27.64 +16 07 21.9 16.9 718
Tianwen1 C2020 07 25.44960 00 52 27.50 +16 07 22.5 16.7 718
Tianwen1 C2020 07 25.44999 00 52 27.33 +16 07 23.6 16.8 718
Tianwen1 C2020 07 25.45117 00 52 26.85 +16 07 25.6 16.8 718
Tianwen1 C2020 07 25.45155 00 52 26.68 +16 07 26.5 16.8 718
Tianwen1 C2020 07 25.45194 00 52 26.54 +16 07 26.9 16.9 718
Tianwen1 C2020 07 25.45350 00 52 25.87 +16 07 30.3 16.7 718
Tianwen1 C2020 07 25.45389 00 52 25.70 +16 07 31.2 16.8 718
Tianwen1 C2020 07 25.45427 00 52 25.56 +16 07 31.8 16.9 718
Tianwen1 C2020 07 25.45466 00 52 25.39 +16 07 32.7 16.7 718
Tianwen1 C2020 07 25.45584 00 52 24.95 +16 07 34.5 16.9 718
Tianwen1 C2020 07 25.45623 00 52 24.76 +16 07 35.6 16.7 718
Tianwen1 C2020 07 25.45662 00 52 24.59 +16 07 36.1 16.8 718
Tianwen1 C2020 07 25.45701 00 52 24.42 +16 07 37.2 16.8 718
Tianwen1 C2020 07 25.45817 00 52 23.93 +16 07 39.3 16.7 718
Tianwen1 C2020 07 25.45856 00 52 23.77 +16 07 40.5 16.7 718
Tianw1A CK200725:211426 013.33091 +16.23091 17.4 GV N88
Tianw1A CK200725:212032 013.32476 +16.23291 17.5 GV N88
Tianw1A CK200725:212641 013.31872 +16.23479 17.5 GV N88
Tianw1A CK200725:213246 013.31263 +16.23659 17.4 GV N88
Tianw1A CK200725:213854 013.30646 +16.23840 17.3 GV N88
TianweA CK200725:23532377 013.49666 +16.16884 17.6 GV J95
TianweA CK200725:23574767 013.49616 +16.17087 17.6 GV J95
TianweA CK200726:00021473 013.49562 +16.17300 17.6 GV J95
TianweA CK200726:00064355 013.49481 +16.17503 17.4 GV J95
TianweA KC2020 07 26.00673900 54 03.81 +16 13 22.1 17.3 G C95
TianweA KC2020 07 26.01718000 54 02.21 +16 13 47.6 17.4 G C95
TianweA KC2020 07 26.02758200 54 00.41 +16 14 12.2 17.4 G C95
TianweA KC2020 07 26.12582700 53 46.239+16 19 20.46 17.5 G Z84
TianweA KC2020 07 26.12750400 53 45.654+16 19 23.11 17.5 G Z84
TianweA KC2020 07 26.12918600 53 45.063+16 19 25.75 17.4 G Z84
Tianw1A CK200726:210348 013.62159 +16.41313 18.8 GV N88
Tianw1A CK200726:210943 013.61718 +16.41439 18.7 GV N88
Tianw1A CK200726:211539 013.61254 +16.41558 18.8 GV N88
Tianw1A CK200726:212136 013.60769 +16.41681 19.0 GV N88
Tianw1A CK200726:212729 013.60301 +16.41789 18.6 GV N88
TianweA KC2020 07 27.12582600 54 43.109+16 28 19.23 18.2 G Z84
TianweA KC2020 07 27.12750700 54 42.636+16 28 21.09 18.2 G Z84
TianweA KC2020 07 27.12919200 54 42.153+16 28 22.75 18.4 G Z84
TianweA C2020 07 28.01278900 55 29.30 +16 30 24.7 18.0 G C95
TianweA C2020 07 28.01410900 55 29.14 +16 30 26.0 18.0 G C95
TianweA C2020 07 28.01539400 55 28.99 +16 30 27.0 17.9 G C95
TianweA C2020 07 28.01666700 55 28.78 +16 30 29.0 17.9 G C95
TianweA C2020 07 28.01790500 55 28.69 +16 30 30.2 17.9 G C95
TianweA C2020 07 28.01913200 55 28.52 +16 30 31.9 17.9 G C95
TianweA CK200728:01364248 013.83672 +16.49459 18.9 GV J95
TianweA CK200728:01423458 013.83437 +16.49573 18.6 GV J95
TianweA CK200728:01482870 013.83196 +16.49676 18.7 GV J95
TianweA KC2020 07 28.12582000 55 16.262+16 33 26.10 18.7 G Z84
TianweA KC2020 07 28.12749700 55 15.867+16 33 27.31 18.6 G Z84
TianweA KC2020 07 28.12917700 55 15.461+16 33 28.62 18.6 G Z84
Tianw1A CK200728:203952 013.89255 +16.57623 19.3 GV N88
Tianw1A CK200728:204045 013.89192 +16.57629 19.1 GV N88
Tianw1A CK200728:204145 013.89171 +16.57633 19.4 GV N88
Tianw1A CK200728:204244 013.89090 +16.57657 19.3 GV N88
Tianw1A CK200728:204350 013.89041 +16.57668 19.3 GV N88
TianweA KC2020 07 29.12582000 55 37.140+16 36 34.59 19.3 G Z84
TianweA KC2020 07 29.12749900 55 36.790+16 36 35.39 19.0 G Z84
TianweA KC2020 07 29.12918000 55 36.447+16 36 36.36 19.3 G Z84
C2YFH42 C2020 07 29.43284 00 55 41.37 +16 38 11.4 19.2 GV G96
C2YFH42 C2020 07 29.43799 00 55 40.27 +16 38 13.8 19.3 GV G96
C2YFH42 C2020 07 29.44316 00 55 39.14 +16 38 16.3 19.3 GV G96
C2YFH42 C2020 07 29.44831 00 55 38.00 +16 38 18.3 19.3 GV G96
TianweA KC2020 07 29.99721100 56 02.77 +16 36 20.3 19.5 G C95
TianweA KC2020 07 30.00678800 56 01.93 +16 36 28.6 19.3 G C95
TianweA KC2020 07 30.01633100 56 00.96 +16 36 35.8 19.2 G C95
TianweA KC2020 07 30.03139500 55 59.36 +16 36 46.5 19.3 G C95
TianweA KC2020 07 30.04594300 55 57.61 +16 36 56.3 24.7 G C95
TianweA KC2020 07 30.06270300 55 55.33 +16 37 07.1 18.7 G C95
Tianw1A CK200730:205039 013.99040 +16.64320 19.2 GV N88
Tianw1A CK200730:205422 013.98870 +16.64356 19.3 GV N88
TianweA KC2020 08 03.12735500 56 07.121+16 42 05.21 x19.4 G Z84
TianweA KC2020 08 03.13210900 56 06.515+16 42 06.42 x19.3 G Z84
TianweA KC2020 08 03.13686600 56 05.898+16 42 07.46 x19.0 G Z84
Station data:
(204) Schiaparelli Observatory (N45.867933 E8.770800) Italy. Observer L.
Buzzi. 0.60-m f/4.64 Newtonian + CCD.
(718) Tooele (N40.641408 W112.295800) US/Utah. Observer P. Wiggins. 0.35-m
f/5.5 Schmidt-Cassegrain + CCD.
(C95) SATINO Remote Observatory, Haute Provence (N43.932042 E5.712390)
France. Observer J. Jahn. 0.60-m f/3.2 Newtonian reflector + CCD.
(G96) Mt. Lemmon Survey (N32.442754 W110.788720) US/Arizona. Observer T.
A. Pruyne. Measurers E. J. Christensen, G. A. Farneth, D. C. Fuls, A. R.
Gibbs, A. D. Grauer, H. Gröller, R. A. Kowalski, S. M. Larson, G. J.
Leonard, T. A. Pruyne, D. Rankin, R. L. Seaman, F. C. Shelly, K. W.
Wierzchoś. 1.5-m reflector + 10K CCD.
(I89) iTelescope Observatory, Nerpio (N38.165287 W2.326100) Spain.
Observer M. Suzuki. 0.15-m f/7.3 refractor + CCD.
(J04) ESA Optical Ground Station, Tenerife (N28.300924 W16.511830) Canary
Islands (Spain). Observer D. Abreu. Measurers M. Micheli, D. Koschny, E.
Schwab, M. Busch, A. Knöfel. 1.0-m f/4.4 reflector + CCD.
(J95) Great Shefford (N51.474969 W1.447003) UK. Observer P. Birtwhistle.
(N88) Xingming Observatory #3, Nanshan (N43.471787 E87.173220) China.
Observer X. Gao. Measurers M. Zhang, Q.-Z. Ye.
(T08) ATLAS-MLO, Mauna Loa (N19.536152 W155.576050) 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.
(Z80) Northolt Branch Observatory (N51.554661 W0.371920) UK. Observer G.
Wells. Measurer D. Bamberger.
(Z84) Calar Alto-Schmidt (N37.223981 W2.548143) Spain. Observer E. Schwab.
Measurers E. Schwab, D. Koschny, M. Micheli. 0.8-m f/3 Schmidt + CCD.
Orbital elements: 2020-049A = NORAD 45935 = Tianwen-1 spacecraft (geocentric escape)
Perigee 2020 Jul 23.21849682 +/- 1.48e-5 TT = 5:14:38.125 (JD 2459053.71849682)
Epoch 2020 Jul 24.0 TT = JDT 2459054.5 Find_Orb
q 6571.98920246 +/- 0.827 (J2000 equator)
H 26.4 G 0.15 Peri. 249.91904731 +/- 0.0031
Node 341.68008391 +/- 0.0045
e 1.1972718520 +/- 4.52e-5 Incl. 29.42030776 +/- 0.00012
110 of 113 observations 2020 July 23-30; mean residual 0".472
Orbital elements: TianweA (heliocentric, Mars cruise)
Perihelion 2020 Jul 18.77620527 +/- 3.81e-5 TT = 18:37:44.135 (JD 2459049.27620527)
Epoch 2020 Oct 1.0 TT = JDT 2459123.5 Earth MOID: 0.0002 Ma: 0.0211
M 48.82201141741 +/- 0.0017 (J2000 ecliptic) Find_Orb
n 0.65776765513 +/- 2.39e-5 Peri. 355.94446566 +/- 0.00017
a 1.30944634186 +/- 3.17e-5 Node 299.92731019 +/- 0.00009
e 0.2243237342 +/- 1.89e-5 Incl. 1.04861980 +/- 0.00006
P 1.50/547.30d H 26.4 G 0.15 U 5.6
q 1.01570644866 +/- 8.46e-8 Q 1.60318623507 +/- 6.36e-5
110 of 113 observations 2020 July 23-30; mean residual 0".314
Orbital elements: TianweA (Mars arrival)
Perimars 2021 Feb 10.59691738 +/- 0.0473 TT = 14:19:33.662 (JD 2459256.09691738)
Epoch 2021 Feb 11.0 TT = JDT 2459256.5 Find_Orb
q 0.02110411511 +/- 3.77e-5 (J2000 ecliptic)
H 26.4 G 0.15 Peri. 240.00398417 +/- 0.007
Node 37.91793513 +/- 0.030
e 396.0791249067 +/- 0.365 Incl. 54.15283844 +/- 0.016
110 of 113 observations 2020 July 23-30; mean residual 0".314
Residuals in arcseconds: 200723 T08 .389+ 1.17+ 200725 718 1.08- .679+ 200727 Z84 .040- .227+ 200723 T08 .184- .139+ 200725 718 1.07- .769+ 200727 Z84 .087- .171+ 200723 T08 .682- 1.14+ 200725 718 .832- .583+ 200728 C95 .558+ .364+ 200723 T08 .772- 1.08+ 200725 718 .963- .878+ 200728 C95 .539+ .065+ 200723 Z80 .765+ 1.00- 200725 718 .853- .458+ 200728 C95 .637+ .484- 200723 Z80 .237+ 1.09- 200725 718 1.04- .583+ 200728 C95 .116- .012- 200723 Z80 .386+ .975- 200725 718 .724- .190+ 200728 C95 .824+ .292- 200724 J04 .670+ .442+ 200725 718 1.05- .443+ 200728 C95 .624+ .051- 200724 J04 .709+ .469+ 200725 718 1.16- .562+ 200728 J95 .001- .234- 200724 J04 .740+ .331+ 200725 718 .895- .403+ 200728 J95 .010+ .018+ 200724 I89 .155- .268+ 200725 718 1.00- .527+ 200728 J95 .090+ .069- 200724 I89 .251- .437+ 200725 718 .248- .007- 200728 Z84 .062+ .055+ 200724 I89 .095- .433+ 200725 718 .637- .326+ 200728 Z84 .130+ .028+ 200724 I89 .491- .520+ 200725 718 .736- .062+ 200728 Z84 .078+ .119+ 200724 J04 .348+ .538+ 200725 718 .833- .400+ 200728 N88 .247+ .027+ 200724 J04 1.01- .763+ 200725 718 .888- .248+ 200728 N88 .314- .160- 200724 J04 1.07- .739+ 200725 718 .835- .696+ 200728 N88 .791+ .471- 200725 Z84 .060+ .172+ 200725 N88 .102- .056+ 200728 N88 .200- .051- 200725 Z84 .047+ .186+ 200725 N88 .630- .246+ 200728 N88 .133+ .149- 200725 Z84 .065+ .211+ 200725 N88 .374- .169+ 200729 Z84 .147+ .121+ 200725 Z84 .044+ .181+ 200725 N88 .309- .101+ 200729 Z84 .098+ .011- 200725 204 .373- .013+ 200725 N88 .153- .240+ 200729 Z84 .177+ .042+ 200725 204 .432- .098- 200725 J95 .342- .042+ 200729 G96 .001- .033+ 200725 204 .456- .086+ 200725 J95 .202- .093- 200729 G96 .157+ .034- 200725 204 .304- .065+ 200726 J95 .136+ .088+ 200729 G96 .123+ .156+ 200725 204 .365- .007+ 200726 J95 .129- .095- 200729 G96 .042+ .022+ 200725 204 .441- .028- 200726 C95 .011+ .098- 200729 C95 .363+ .470- 200725 204 .363- .068+ 200726 C95 .269- .002- 200730 C95 .336+ .115+ 200725 204 .471- .006- 200726 C95 .046+ .115+ 200730 C95 .275- .108- 200725 204 .430- .018+ 200726 Z84 .229- .237+ 200730 C95 .325+ .535- 200725 204 .535- .060- 200726 Z84 .196- .224+ 200730 C95 .720+ .726- 200725 Z84 .436- .279+ 200726 Z84 .180- .228+ 200730 C95 .416+ .431- 200725 Z84 .411- .313+ 200726 N88 .578- .040+ 200730 N88 .492+ .231- 200725 Z84 .443- .274+ 200726 N88 .034+ .124+ 200730 N88 .184+ .098+ 200725 Z84 .468- .304+ 200726 N88 .087+ .093+ 200803 Z84(31.4+ 81.7+) 200725 Z84 .863- .259+ 200726 N88 .363- .345+ 200803 Z84(31.6+ 82.2+) 200725 718 .806- .940+ 200726 N88 .248- .255+ 200803 Z84(31.7+ 82.5+) 200725 718 .806- .221+ 200727 Z84 .086- .104+ Ephemerides (geocentric): Date (UTC) RA Dec delta r elong mag " sig PA ---- ----- -------------- ----------- ----- ------ ----- --- -------- 2020 07 24 00 42 55.560 +15 18 56.87 296194 1.0164 105.2 15.6 .887 92 2020 07 25 00 50 35.157 +16 10 45.41 616572 1.0168 104.1 17.2 .374 96 2020 07 26 00 53 00.820 +16 26 37.07 928156 1.0172 104.4 18.1 .208 100 2020 07 27 00 54 11.694 +16 34 03.87 .00826 1.0177 105.0 18.7 .125 106 2020 07 28 00 54 52.735 +16 38 10.61 .01031 1.0183 105.8 19.1 .076 117 2020 07 29 00 55 18.687 +16 40 36.84 .01234 1.0189 106.6 19.5 .046 137 2020 07 30 00 55 35.766 +16 42 04.71 .01437 1.0196 107.5 19.8 .034 173 2020 07 31 00 55 46.990 +16 42 54.82 .01640 1.0204 108.4 20.0 .038 27 2020 08 01 00 55 53.942 +16 43 18.10 .01841 1.0212 109.3 20.2 .049 45 2020 08 02 00 55 57.489 +16 43 20.53 .02042 1.0221 110.2 20.4 .061 55 2020 08 03 00 55 58.104 +16 43 05.38 .02243 1.0230 111.1 20.6 .072 60 2020 08 04 00 55 56.039 +16 42 34.25 .02443 1.0240 112.1 20.8 .083 64 2020 08 05 00 55 51.417 +16 41 47.79 .02642 1.0250 113.0 20.9 .093 66 2020 08 06 00 55 44.287 +16 40 46.01 .02841 1.0262 114.0 21.0 .102 67 2020 08 07 00 55 34.656 +16 39 28.56 .03039 1.0273 115.0 21.2 .110 68 2020 08 08 00 55 22.511 +16 37 54.85 .03237 1.0286 116.0 21.3 .117 69 2020 08 09 00 55 07.830 +16 36 04.21 .03434 1.0299 117.0 21.4 .124 69 2020 08 10 00 54 50.591 +16 33 55.89 .03630 1.0312 118.0 21.4 .130 70 2020 08 11 00 54 30.773 +16 31 29.15 .03826 1.0326 119.1 21.5 .135 70 2020 08 12 00 54 08.363 +16 28 43.23 .04022 1.0341 120.1 21.6 .140 70 2020 08 13 00 53 43.355 +16 25 37.43 .04217 1.0356 121.2 21.7 .143 70 2020 08 14 00 53 15.753 +16 22 11.08 .04412 1.0372 122.2 21.8 .146 70 2020 08 15 00 52 45.574 +16 18 23.58 .04607 1.0388 123.3 21.8 .149 70 2020 08 16 00 52 12.850 +16 14 14.40 .04801 1.0405 124.4 21.9 .151 70 2020 08 17 00 51 37.635 +16 09 43.14 .04995 1.0423 125.5 21.9 .152 70 2020 08 18 00 51 00.001 +16 04 49.57 .05190 1.0441 126.6 22.0 .152 70 2020 08 19 00 50 20.047 +15 59 33.63 .05385 1.0459 127.7 22.0 .152 71 2020 08 20 00 49 37.893 +15 53 55.48 .05580 1.0478 128.9 22.1 .151 71 2020 08 21 00 48 53.680 +15 47 55.52 .05776 1.0497 130.0 22.1 .150 71 2020 08 22 00 48 07.557 +15 41 34.34 .05972 1.0517 131.1 22.2 .149 71