Goldstone Radar Observations Planning: (5645) 1990 SP
1990 SP was discovered on September 20, 1990 by Rob McNaught at Siding
Spring, Australia, as part of the Anglo-Australian Near-Earth Asteroid Survey (AANEAS).
This asteroid has been studied extensively and a number of its physical properties are
reasonably well known. Photometry reported by Pravec et al. (2005) indicates slow,
probably non-principal rotation with a fundamental period of about 30.4 hours.
The lightcurve amplitude of 0.7 magnitudes suggests an elongated shape.
Visible-NIR spectroscopy reported by Lazzarin et al. (2004) places 1990 SP into the Xe
spectral class that is consistent with a wide range of compositions and optical
albedos. Thermal infrared observations by the Spitzer Space Telescope (Mueller et al. 2011)
give a diameter of 2.2 km and an optical albedo of 0.06. Observations by the WISE
spacecraft suggest a somewhat smaller diameter of 1.7 km and a brighter optical albedo
of 0.12 (Mainzer et al. 2011). The differences in estimated diameters are
consistent within their stated uncertainties, but they could also result from observations
obtained when the asteroid was at different orientations, and thus appear to have different
diameters due to the elongated shape.
This asteroid will approach within 0.143 au on 2020 October 17 and we
expect SNRs at Goldstone that should be strong enough for CW observations and ranging.
The SNRs at Arecibo will be strong enough for delay-Doppler imaging but it is not known
yet if Arecibo will be able to observe this asteroid due to a cable failure in August.
Observations at Goldstone are scheduled on October 15.
1990 SP will be brighter than 17th magnitude from early September to late October, 2020, and will
be a good target for photometry. New photometric observations would be particularly valuable
because the rotation is slow and the spin state is not known precisely.
The 2020 Earth flyby is the closest by this asteroid until 2031 when 1990 SP
will approach within 0.0985 au.
Goldstone Radar Data from Near-Earth Asteroid 1990 SP
Echo power spectrum from 1990 SP obtained on October 15, 2020. The resolution is 0.2 Hz.
The echo has a bandwidth of about 3 Hz, which places a lower bound on the maximum pole-on breadth
of about 0.9 km. Given larger published estimates, this hints that the subradar latitude was
well off the equator and/or that the shape is significantly elongated and that the radar view
was close to end-on. The shape of the echo suggests that 1990 SP is asymmetric.
Orbital and Physical Characteristics
Name 1990 SP
Asteroid number 5645
Discoverer R. H. McNaught/AANEAS
Discovery date 1990 Sep 20
orbit type Apollo
Close approach distance 0.142 au (55.3 lunar distances or 21 million km)
Close approach date 2020 Oct 17
semimajor axis 1.355 au
eccentricity 0.387
inclination 13.5 deg
Orbital period 1.58 years
perihelion distance 0.830 au
aphelion distance 1.879 au
MOID 0.0543 au
absolute magnitude (H) 17.1
diameter 1.7 km WISE: Mainzer et al. 2011
2.20 +0.74 -0.64 km Spitzer: Mueller et al. 2011
optical albedo 0.12 WISE: Mainzer et al. 2011
0.06 +0.079 -0.034 Spitzer: Mueller et al. 2011
rotation period 30.39 h Pravec et al. 2005
lightcurve amplitude 0.7 mag Pravec et al. 2005
pole direction unknown
spectral class Xe Lazzarin et al. 2004
PHA? No
Last update: 2020 November 11
Discovery M.P.E.C.
The discovery was probably announced in an IAU Circular in Sep. 1990.
SNR Calculations
Goldstone SNRs
(5645) 1990 SP: D = 1.7 km, P = 30.39 h, OC albedo = 0.1
w DOY start date window RA, dec dist runs SNR/day SNR/run
41 282 2020 Oct 08 09:33-16:36 97, -14 0.161 78 26 3
41 283 2020 Oct 09 09:37-16:47 99, -13 0.157 82 29 4
41 284 2020 Oct 10 09:41-16:58 102, -12 0.154 85 32 4
41 285 2020 Oct 11 09:45-17:10 105, -11 0.151 88 35 4
42 286 2020 Oct 12 09:49-17:23 108, -10 0.148 91 38 4
42 287 2020 Oct 13 09:53-17:35 111, -9 0.146 94 41 5
42 288 2020 Oct 14 09:58-17:48 115, -8 0.144 97 44 5
42 289 2020 Oct 15 10:02-18:02 118, -7 0.143 100 46 5 * SCHEDULED
42 290 2020 Oct 16 10:07-18:15 121, -5 0.142 102 48 5
42 291 2020 Oct 17 10:12-18:29 124, -4 0.142 104 49 5
42 292 2020 Oct 18 10:17-18:42 128, -3 0.142 106 49 5
43 293 2020 Oct 19 10:22-18:55 131, -2 0.143 107 49 5
43 294 2020 Oct 20 10:27-19:08 134, 0 0.144 108 48 5
43 295 2020 Oct 21 10:31-19:21 137, +1 0.146 108 46 5
43 296 2020 Oct 22 10:36-19:33 140, +2 0.148 108 44 5
43 297 2020 Oct 23 10:41-19:44 143, +3 0.151 107 41 4
43 298 2020 Oct 24 10:45-19:55 146, +4 0.154 107 38 4
43 299 2020 Oct 25 10:50-20:06 149, +5 0.157 105 35 4
44 300 2020 Oct 26 10:54-20:15 152, +6 0.161 104 32 3
44 301 2020 Oct 27 10:58-20:24 155, +7 0.165 102 29 3
Goldstone has only one klystron and full power is not expected until Nov. 2020.
The SNRs assume Ptx = 450 kW and are probably optimistic by about a factor of two.
1990 SP ARECIBO SNRs
start date window RA, dec dist runs SNR/day SNR/run
2020 Oct 20 11:03-11:47 134, -1 0.144 9 240 83
2020 Oct 21 10:59-12:09 137, +1 0.146 14 330 93
2020 Oct 22 10:58-12:27 140, +2 0.148 17 370 98
2020 Oct 23 11:00-12:41 143, +3 0.150 20 400 100
2020 Oct 24 11:02-12:54 146, +4 0.153 21 410 98
2020 Oct 25 11:06-13:06 149, +5 0.157 23 400 91
2020 Oct 26 11:09-13:16 152, +6 0.160 23 380 84
2020 Oct 27 11:13-13:26 154, +7 0.165 24 350 76
2020 Oct 28 11:17-13:34 157, +8 0.169 24 320 69
2020 Oct 29 11:20-13:42 159, +9 0.174 24 290 63
2020 Oct 30 11:24-13:49 162, +9 0.179 24 270 57
2020 Oct 31 11:28-13:55 164, +10 0.184 24 240 51
2020 Nov 01 11:31-14:01 166, +11 0.190 23 210 46
2020 Nov 02 11:34-14:06 168, +11 0.196 23 190 42
2020 Nov 03 11:37-14:11 170, +12 0.202 22 170 37
2020 Nov 04 11:40-14:15 172, +12 0.208 22 150 33
2020 Nov 05 11:43-14:19 173, +12 0.215 21 130 30
2020 Nov 06 11:45-14:22 175, +13 0.221 21 120 27
2020 Nov 07 11:47-14:25 177, +13 0.228 20 100 24
2020 Nov 08 11:49-14:27 178, +13 0.235 20 94 22
2020 Nov 09 11:51-14:30 180, +13 0.242 19 83 20
2020 Nov 10 11:52-14:32 181, +14 0.249 19 75 18
2020 Nov 11 11:54-14:33 183, +14 0.257 18 66 16
2020 Nov 12 11:55-14:35 184, +14 0.264 18 59 15
2020 Nov 13 11:56-14:36 185, +14 0.272 17 53 13
2020 Nov 14 11:57-14:37 186, +14 0.279 17 48 12
Arecibo SNRs assume Ptx = 700 kW, Tsys = 25 K, and D = 1.7 km. The SNRs
will be weaker because the gain is about 30% lower than assumed here due to damage
sustained from Hurricane Maria in 2017.
Unfortunately, Arecibo will probably not be operational following a cable failure
in August, 2020.
Track Assignments
DOY BOA BOT EOT EOA
289 1310 1440 1800 1830 GSSR AST 1990 SP
Goldstone tracks:
UT UT PDT Duration Round-trip
DOY Date TX Window TX Window hh:mm time (sec) SNR/run
289 Oct 15 1440-1800 0740-1100 Oct 15 3:20 143 3
The asteroid will be more than 20 degrees above the horizon by the time precal
starts, so we can begin observing as soon as we're ready, possibly as early as 13:40 UT
(06:40 PDT).
SNR/run assumes ~1/2 power with only one klystron
Arecibo tracks:
UT UT PST Round-trip
Date TX Window TX Window time (sec)
...Not scheduled due to the cable failure...
Uncertainties
1990 SP
The 3-sigma pointing and Doppler uncertainties are small. We might not see a Doppler correction
to the ephemeris.
JPL/Horizons solution 136, # obs: 707 (1974-2020)
2020 October 12
Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta POS_3sigma DOP_S_3sig DOP_X_3sig RT_delay_3sig
2020-Oct-10 00:00 * 100.68741 -12.60288 0.15538941286467 0.406 0.38 1.40 0.000264
2020-Oct-11 00:00 * 103.58887 -11.68697 0.15224567540910 0.412 0.40 1.44 0.000267
2020-Oct-12 00:00 * 106.57897 -10.70395 0.14948585388491 0.417 0.41 1.48 0.000271
2020-Oct-13 00:00 * 109.64860 -9.65690 0.14713245172491 0.422 0.42 1.51 0.000275
2020-Oct-14 00:00 * 112.78655 -8.55086 0.14520648941426 0.426 0.42 1.54 0.000279
*2020-Oct-15 00:00 *m 115.97959 -7.39287 0.14372677688749 0.428 0.43 1.56 0.000283 *
2020-Oct-16 00:00 *m 119.21278 -6.19186 0.14270919072490 0.429 0.43 1.57 0.000287
2020-Oct-17 00:00 *m 122.46989 -4.95848 0.14216601092646 0.429 0.43 1.57 0.000291
2020-Oct-18 00:00 *m 125.73390 -3.70472 0.14210537520447 0.429 0.43 1.57 0.000295
2020-Oct-19 00:00 *m 128.98753 -2.44336 0.14253090503222 0.427 0.43 1.55 0.000299
2020-Oct-20 00:00 *m 132.21390 -1.18745 0.14344154531959 0.424 0.42 1.54 0.000302
- - - - - - - - - -
JPL/Horizons solution 130, # obs: 614 (1974-2020)
2020 September 11
Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta POS_3sigma DOP_S_3sig DOP_X_3sig RT_delay_3sig
2020-Oct-10 00:00 * 100.68741 -12.60290 0.15538939796082 0.644 0.54 1.96 0.000381
2020-Oct-11 00:00 * 103.58887 -11.68699 0.15224565957314 0.647 0.55 2.00 0.000392
2020-Oct-12 00:00 * 106.57897 -10.70397 0.14948583706613 0.647 0.56 2.04 0.000405
2020-Oct-13 00:00 * 109.64860 -9.65692 0.14713243388191 0.644 0.57 2.06 0.000417
2020-Oct-14 00:00 * 112.78655 -8.55088 0.14520647051678 0.639 0.57 2.07 0.000429
*2020-Oct-15 00:00 *m 115.97959 -7.39289 0.14372675691797 0.632 0.57 2.06 0.000442*
2020-Oct-16 00:00 *m 119.21278 -6.19187 0.14270916967952 0.621 0.56 2.03 0.000454
2020-Oct-17 00:00 *m 122.46989 -4.95850 0.14216598881564 0.609 0.55 1.99 0.000466
2020-Oct-18 00:00 *m 125.73390 -3.70473 0.14210535205276 0.595 0.53 1.94 0.000477
2020-Oct-19 00:00 *m 128.98753 -2.44337 0.14253088087747 0.580 0.52 1.88 0.000487
2020-Oct-20 00:00 *m 132.21390 -1.18747 0.14344152021143 0.563 0.50 1.81 0.000497
Apparent Magnitudes, Solar Elongations, Lunar Elongations, and Lunar Illumination:
Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta APmag S-brt S-O-T /r T-O-M/MN_Illu%
2020-Sep-20 00:00 62.05970 -20.00215 0.26873655578096 16.487 5.644 114.3623 /L 138.9/ 9.6396
2020-Sep-22 00:00 64.61133 -19.84398 0.25464438012801 16.387 5.646 113.3958 /L 141.1/ 27.5806
2020-Sep-24 00:00 67.36991 -19.61353 0.24097310416887 16.288 5.652 112.2502 /L 130.9/ 49.2564
2020-Sep-26 00:00 70.36539 -19.29470 0.22776775124763 16.193 5.661 110.9022 /L 115.9/ 69.9070
2020-Sep-28 00:00 73.63056 -18.86831 0.21508513678561 16.102 5.673 109.3256 /L 100.0/ 86.3174
2020-Sep-30 00:00 77.20037 -18.31174 0.20299688999867 16.018 5.690 107.4913 /L 84.7/ 96.5911
2020-Oct-02 00:00 81.11039 -17.59874 0.19159248599315 15.943 5.712 105.3685 /L 70.4/ 99.8140
2020-Oct-04 00:00 85.39408 -16.69999 0.18098204153907 15.881 5.739 102.9268 /L 57.7/ 95.9118
2020-Oct-06 00:00 90.07869 -15.58469 0.17129828162914 15.835 5.772 100.1398 /L 47.1/ 85.5219
2020-Oct-08 00:00 95.17933 -14.22401 0.16269662147107 15.812 5.813 96.9914 /L 39.8/ 69.8090
2020-Oct-10 00:00 100.69165 -12.59670 0.15535184746905 15.815 5.861 93.4838 /L 37.9/ 50.4120
2020-Oct-12 00:00 106.58422 -10.69699 0.14944968237104 15.851 5.916 89.6481 /L 43.2/ 29.7655
2020-Oct-14 00:00 112.79285 -8.54311 0.14517208201772 15.924 5.980 85.5528 /L 55.6/ 11.6832
2020-Oct-16 00:00 119.22011 -6.18335 0.14267692080539 16.038 6.051 81.3077 /L 73.3/ 1.2022
2020-Oct-18 00:00 125.74216 -3.69558 0.14207557278218 16.189 6.126 77.0565 /L 93.9/ 2.2607
2020-Oct-20 00:00 132.22293 -1.17787 0.14341444964682 16.374 6.203 72.9584 /L 115.6/ 14.5491
2020-Oct-22 00:00 138.53182 1.26789 0.14666694812410 16.583 6.279 69.1617 /L 136.8/ 33.7294
2020-Oct-24 00:00 144.55975 3.55350 0.15173912000370 16.804 6.347 65.7799 /L 156.4/ 54.7096
Setups
Due the 30.4 h rotation period and a diameter of roughly 1.7 km, we are expecting a bandwidth
of about 6 Hz. The shape appears elongated so the bandwidth could vary considerably as
the asteroid spins.
CW setup:
---------------------------------------------------------------------------
TX polarization RCP
RCV polarization LCP & RCP
Frequency hops: no hopping
Bandwidth: 5000 Hz
TXoffset +500 Hz
FFT 5000 for 1.0 Hz resolution
Ranging setups:
---------------------------------------------------------------------------
10-usec
baud 10 usec
code 127
PRP 1270 usec
ncoh 1
bandwidth 787 Hz
FFT 128
resolution 6.15 Hz
TXoffset +100 Hz (echo in column 80)
---------------------------------------------------------------------------
11-usec
baud 11 usec
code 127
PRP 1397 usec
ncoh 1
bandwidth 716 Hz
FFT 128
resolution 5.6 Hz
TXoffset +100 Hz (echo in column 82)
-------------------------------------------------------------------------
1-usec
baud 1 usec
code 255
ncoh 8
bandwidth 245 Hz
FFT 128
resolution 3.8 Hz
TXoffset +50 Hz (echo in column 116)
---------------------------------------------------------------------
NOTE: Data should be moved to the appropriate subdirectories in
aardvark:/export/data0/1990sp/raw/
OSOD and predicts are on aardvark:
/export/data3/osod/ops/a5645/EPH.OUT.s136
/export/data3/osod/ops/a5645/PRDX.OUT.14f-14-14.s136
/export/data3/osod/ops/a5645/PRDX.OUT.14v-14-14.s136
/export/data3/osod/ops/a5645/PUNCH.OUT.14f-14-14.s136
/export/data3/osod/ops/a5645/PUNCH.OUT.14v-14-14.s136
POINTING
1990 SP DSS-14 Pointing
TX Offsets
Date (UTC) DOY hhmmss RA Dec LHA Dec RTT OSOD
2020 OCT 15 289 130000 117.7378 -6.7500 -7.9 2.0 142.8 136
2020 OCT 15 289 140000 117.8690 -6.6999 -7.7 2.0 142.7
2020 OCT 15 289 150000 118.0003 -6.6496 -6.2 2.0 142.7
2020 OCT 15 289 160000 118.1319 -6.5991 -4.4 2.0 142.7
2020 OCT 15 289 170000 118.2640 -6.5485 -3.0 2.0 142.6
2020 OCT 15 289 180000 118.3968 -6.4978 -2.1 2.1 142.6
Transmit offsets are given in millidegrees.
PRDX.OUT.14f-14-14.s136
TRANSMITTER: STATION #14, RECEIVER: STATION #14
RECEIVER U.T. RANGE DOPPLER LHA DEC RA EL
2020 OCT 15 13:00 142.7819680433 104342.349 158.3297 -6.7500 117.7378 45.4883 104342.349 0.0000000026
2020 OCT 15 13:10 142.7746969960 103123.179 161.7268 -6.7417 117.7597 46.1881 103123.179 0.0000000013
2020 OCT 15 13:20 142.7675117331 101894.932 165.2090 -6.7333 117.7815 46.7726 101894.932 0.0000000011
2020 OCT 15 13:30 142.7604128310 100659.313 168.7636 -6.7250 117.8034 47.2369 100659.313 0.0000000008
2020 OCT 15 13:40 142.7534007466 99418.038 172.3757 -6.7166 117.8253 47.5770 99418.038 0.0000000010
2020 OCT 15 13:50 142.7464758157 98172.836 176.0282 -6.7082 117.8472 47.7900 98172.836 0.0000000018
2020 OCT 15 14:00 142.7396382496 96925.442 179.7028 -6.6999 117.8690 47.8738 96925.442 -0.0000000001
2020 OCT 15 14:10 142.7328881442 95677.595 183.3803 -6.6915 117.8909 47.8276 95677.595 -0.0000000014
2020 OCT 15 14:20 142.7262254737 94431.037 187.0414 -6.6831 117.9128 47.6520 94431.037 0.0000000008
2020 OCT 15 14:30 142.7196500767 93187.504 190.6673 -6.6748 117.9346 47.3486 93187.504 -0.0000000026
2020 OCT 15 14:40 142.7131616938 91948.729 194.2407 -6.6664 117.9565 46.9201 91948.729 0.0000000009
2020 OCT 15 14:50 142.7067599177 90716.434 197.7459 -6.6580 117.9784 46.3702 90716.434 -0.0000000016
2020 OCT 15 15:00 142.7004442407 89492.331 201.1697 -6.6496 118.0003 45.7036 89492.331 -0.0000000035
2020 OCT 15 15:10 142.6942140357 88278.115 204.5011 -6.6412 118.0222 44.9256 88278.115 0.0000000013
2020 OCT 15 15:20 142.6880685376 87075.462 207.7317 -6.6328 118.0441 44.0419 87075.462 0.0000000005
2020 OCT 15 15:30 142.6820068841 85886.027 210.8559 -6.6244 118.0660 43.0587 85886.027 -0.0000000001
2020 OCT 15 15:40 142.6760280916 84711.439 213.8700 -6.6160 118.0880 41.9822 84711.439 -0.0000000007
2020 OCT 15 15:50 142.6701310629 83553.301 216.7725 -6.6075 118.1099 40.8188 83553.301 -0.0000000013
2020 OCT 15 16:00 142.6643145895 82413.182 219.5639 -6.5991 118.1319 39.5746 82413.182 -0.0000000015
2020 OCT 15 16:10 142.6585773545 81292.620 222.2459 -6.5907 118.1539 38.2558 81292.620 -0.0000000023
2020 OCT 15 16:20 142.6529179339 80193.115 224.8214 -6.5823 118.1758 36.8679 80193.115 -0.0000000030
2020 OCT 15 16:30 142.6473348071 79116.125 227.2943 -6.5738 118.1979 35.4167 79116.125 0.0000000024
2020 OCT 15 16:40 142.6418263324 78063.068 229.6692 -6.5654 118.2199 33.9072 78063.068 0.0000000001
2020 OCT 15 16:50 142.6363907905 77035.318 231.9511 -6.5570 118.2419 32.3444 77035.318 -0.0000000026
2020 OCT 15 17:00 142.6310263674 76034.197 234.1451 -6.5485 118.2640 30.7326 76034.197 0.0000000007
2020 OCT 15 17:10 142.6257311379 75060.981 236.2567 -6.5401 118.2861 29.0762 75060.981 -0.0000000041
2020 OCT 15 17:20 142.6205031162 74116.892 238.2914 -6.5316 118.3081 27.3789 74116.892 -0.0000000030
2020 OCT 15 17:30 142.6153402128 73203.095 240.2546 -6.5231 118.3303 25.6445 73203.095 -0.0000000033
2020 OCT 15 17:40 142.6102402648 72320.701 242.1516 -6.5147 118.3524 23.8760 72320.701 -0.0000000048
2020 OCT 15 17:50 142.6052010405 71470.759 243.9875 -6.5062 118.3746 22.0767 71470.759 -0.0000000013
2020 OCT 15 18:00 142.6002202232 70654.260 245.7675 -6.4978 118.3968 20.2492 70654.260 0.0000000006
Receive
Setup code ncoh FFT runs start -stop OSOD offset
CW, no hops - - 25000 11 145009-154312 136 +500 Hz Ptx = 260 kW
Stopped early due to a high voltage problem.
Dr. Lance A. M. Benner | PHONE: (818) 354-7412
Mail Stop 183-601 | FAX: (818) 393-4445
Jet Propulsion Laboratory | email: lance.benner@jpl.nasa.gov
California Institute of Technology | Plan: To live long and prosper
Pasadena, CA 91109-8099
https://echo.jpl.nasa.gov/asteroids/1990SP/1990sp.2020.planning.html
Asteroid Radar Astronomy