Goldstone Radar Observations Planning: 2002 SR41
2002 SR41 was discovered on 2002 Sep. 30 by LINEAR. It will approach within 0.042 AU of Earth on June 9. This object was observed with radar at Arecibo in 2005. The echoes had a bandwidth of about 7 Hz when converted from S- to X-band and a circular polarization ratio of 0.2. The absolute magnitude of 20.2 suggests a diameter within a factor of two of 0.3 km, but otherwise nothing is known about this asteroid, although the Arecibo bandwidth implies that this is not a slow rotator. 2002 SR41 will approach from the direction of the Sun. Fortunately the orbit is already really good so we don't need any optical astrometry before the Goldstone observations begin. We are expecting this to be a moderately strong radar target with SNRs good enough for ranging and perhaps coarse-resolution imaging. Three tracks are scheduled at Goldstone from June 8-11. Two tracks are scheduled at Arecibo on June 20 and 21. The Minor Planet Center has classified 2002 SR41 as a "Potentially Hazardous Asteroid."
Orbital and Physical Characteristics Provisional Designation 2002 SR41 Asteroid number 154275 Discoverer LINEAR Discovery date 2002 Sep 30 orbit type Apollo Close approach dist. 0.042 AU Close approach dist. 16.3 lunar distances Close approach date June 9 semimajor axis 1.083 eccentricity 0.491 inclination 11.6 deg perihelion distance 0.552 AU aphelion distance 1.615 AU Tisserand parameter absolute magnitude (H) 20.2 diameter 0.3 km +- a factor of two optical albedo unknown rotation period unknown pole direction unknown lightcurve amplitude unknown spectral class unknown Last update: 2014 Jun 05
2002 SR41 http://www.minorplanetcenter.net/mpec/K02/K02T05.html
GOLDSTONE SNRS 2002 SR41: D = 0.29 km, P = 2.2 h, OC albedo = 0.1, subradar lat = 0.0 deg w DOY start date window RA, dec dist Runs SNR/day SNR/run 23 154-155 2014 Jun 03-04 14:53-02:54 88, +35 0.067 314 22 1 23 155-156 2014 Jun 04-05 14:51-03:25 92, +40 0.059 365 36 2 23 156-157 2014 Jun 05-06 14:52-04:11 98, +46 0.053 430 59 3 23 157-158 2014 Jun 06-07 14:58-05:25 108, +53 0.047 509 93 4 23 158-159 2014 Jun 07-08 15:20-07:23 126, +60 0.044 598 130 6 23 159-160 2014 Jun 08-09 16:21-09:37 154, +64 0.042 658 160 7 * Scheduled 24 160-161 2014 Jun 09-10 18:27-10:51 185, +61 0.043 619 150 6 24 161-162 2014 Jun 10-11 20:36-11:18 205, +55 0.046 533 110 5 24 162-163 2014 Jun 11-12 21:59-11:26 216, +47 0.051 451 70 4 24 163-164 2014 Jun 12-13 22:51-11:27 223, +41 0.057 383 43 2 24 164-165 2014 Jun 13-14 23:25-11:25 228, +35 0.063 328 27 2 24 165-166 2014 Jun 14-15 23:48-11:22 231, +31 0.071 284 17 1 Goldstone SNRs assume Ptx = 440 kW and Tsys = 17 K ARECIBO SNRS start date window RA, dec dist Runs SNR/day SNR/run 2014 May 29 15:49-18:35 78, +21 0.111 44 16 2 2014 May 30 15:50-18:34 79, +23 0.102 48 22 3 2014 May 31 15:54-18:33 81, +25 0.093 51 32 5 2014 Jun 01 16:01-18:32 82, +28 0.084 53 45 6 2014 Jun 02 16:14-18:28 85, +31 0.076 52 62 9 2014 Jun 03 16:39-18:16 87, +35 0.068 42 71 12 ...Too far north from June 4-13... 2014 Jun 14 01:28-02:47 227, +36 0.062 37 81 14 2014 Jun 15 01:11-03:22 230, +32 0.070 55 83 12 2014 Jun 16 01:07-03:38 233, +28 0.078 57 61 8 2014 Jun 17 01:05-03:46 235, +25 0.086 55 43 6 2014 Jun 18 01:05-03:50 236, +22 0.094 51 30 4 2014 Jun 19 01:05-03:52 238, +20 0.103 48 21 3 2014 Jun 20 01:06-03:52 239, +18 0.112 40 15 2 Arecibo SNRs assume Ptx = 900 kW and Tsys = 25 K.
Track Assignments
Goldstone tracks: UT UT PDT Duration Round-trip DOY Date TX Window TX Window hh:mm time (sec) SNR/run 160 Jun 09 0225-0920 1925-0220 Jun 08-09 6:55 42 7 Times above refer to when we have transmit authorization. Arecibo tracks: UT UT PDT Duration Round-trip DOY Date TX Window TX Window hh:mm time (sec) 171 Jun 20 0106-0352 1806-2052 Jun 19 2:46 112 The SNR will be weak 172 Jun 21 0106-0350 1806-2040 Jun 20 2:44 120 The SNR will be weak
Uncertainties
JPL/Horizons solution 52, # obs: 199 (2002-2013) Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta POS_3sigma DOP_S_3sig DOP_X_3sig RT_delay_3sig 2014-May-30 00:00 *m 78.53730 21.55804 0.10811468200663 1.581 0.33 1.19 0.000703 2014-May-31 00:00 *m 79.69287 23.49239 0.09901025102657 1.716 0.31 1.13 0.000694 2014-Jun-01 00:00 *m 81.11066 25.79987 0.09014201922491 1.872 0.30 1.10 0.000686 2014-Jun-02 00:00 *m 82.89348 28.57881 0.08155946799914 2.053 0.31 1.13 0.000678 2014-Jun-03 00:00 *m 85.20293 31.95555 0.07333560136598 2.266 0.34 1.25 0.000671 2014-Jun-04 00:00 *m 88.30637 36.08445 0.06557841762762 2.517 0.41 1.50 0.000664 2014-Jun-05 00:00 *m 92.67293 41.12848 0.05844736759763 2.813 0.55 1.98 0.000653 2014-Jun-06 00:00 *m 99.17892 47.18023 0.05217389619453 3.160 0.79 2.88 0.000637 2014-Jun-07 00:00 *m 109.53353 54.02372 0.04707749051601 3.553 1.22 4.42 0.000608 2014-Jun-08 00:00 *m 126.80508 60.55853 0.04355098452330 3.955 1.82 6.61 0.000559 2014-Jun-09 00:00 *m 153.33338 64.08681 0.04197294959068 4.272 2.42 8.80 0.000488 2014-Jun-10 00:00 *m 181.90473 62.02240 0.04254596507753 4.387 2.73 9.93 0.000399 2014-Jun-11 00:00 * 202.11983 55.84707 0.04517789019756 4.253 2.62 9.53 0.000308 2014-Jun-12 00:00 * 214.28508 48.65671 0.04953522835841 3.938 2.23 8.10 0.000230 2014-Jun-13 00:00 * 221.78146 42.05353 0.05520783300124 3.550 1.76 6.39 0.000173 2014-Jun-14 00:00 * 226.71409 36.47076 0.06183428801836 3.164 1.33 4.85 0.000137 2014-Jun-15 00:00 * 230.16469 31.87666 0.06914246666972 2.814 0.99 3.60 0.000121 2014-Jun-16 00:00 * 232.70191 28.11065 0.07694154606550 2.510 0.73 2.65 0.000117 2014-Jun-17 00:00 * 234.64337 25.00426 0.08510111109788 2.252 0.53 1.93 0.000119 2014-Jun-18 00:00 * 236.17764 22.41536 0.09353226830141 2.033 0.39 1.40 0.000123 2014-Jun-19 00:00 * 237.42279 20.23230 0.10217392618943 1.846 0.28 1.01 0.000127 ********************************************************************************************** Apparent Magnitudes, Solar Elongations, Lunar Elongations, and Lunar Illumination: Date__(UT)__HR:MN R.A._(a-appar)_DEC. delta APmag S-O-T /r T-O-M/Illu% 2014-May-25 00:00 74.91428 15.39148 0.15635340797832 28. 13.6852 /T 57.7/ 15.1 2014-May-26 00:00 75.45757 16.29447 0.14639613400800 29. 12.9620 /T 44.9/ 8.2 2014-May-27 00:00 76.07126 17.33269 0.13658880507481 29. 12.2703 /T 32.3/ 3.4 2014-May-28 00:00 76.77382 18.53289 0.12693699850919 30. 11.6491 /T 20.0/ 0.7 2014-May-29 00:00 77.58984 19.92927 0.11745027063997 30. 11.1655 /T 8.166/ 0.1 2014-May-30 00:00 78.55287 21.56597 0.10814363992789 30. 10.9270 /T 4.317/ 1.7 2014-May-31 00:00 79.71007 23.50045 0.09903977317066 30. 11.0907 /T 15.3/ 5.1 2014-Jun-01 00:00 81.12980 25.80791 0.09017226540675 29. 11.8540 /T 26.3/ 10.1 2014-Jun-02 00:00 82.91492 28.58652 0.08159062406243 28. 13.4246 /T 36.9/ 16.6 2014-Jun-03 00:00 85.22714 31.96242 0.07336787465504 26. 15.9962 /T 47.0/ 24.2 2014-Jun-04 00:00 88.33388 36.08960 0.06561201872941 25. 19.7618 /T 56.6/ 32.7 2014-Jun-05 00:00 92.70417 41.13039 0.05848246208778 23. 24.9491 /T 65.5/ 41.9 2014-Jun-06 00:00 99.21362 47.17654 0.05221049949950 22. 31.8276 /T 73.2/ 51.5 2014-Jun-07 00:00 109.56820 54.01128 0.04711528184418 20. 40.6350 /T 79.1/ 61.2 2014-Jun-08 00:00 126.82522 60.53553 0.04358908441704 19. 51.3731 /T 82.3/ 70.6 2014-Jun-09 00:00 153.30893 64.05988 0.04200988282794 17.75 63.5234 /T 82.4/ 79.5 2014-Jun-10 00:00 181.83981 62.00652 0.04258008790528 17.07 75.9824 /T 79.6/ 87.4 2014-Jun-11 00:00 202.05192 55.84621 0.04520808145633 16.68 87.5077 /T 75.4/ 93.7 2014-Jun-12 00:00 214.22749 48.66566 0.04956120327652 16.52 97.3169 /T 71.7/ 98.0 2014-Jun-13 00:00 221.73399 42.06725 0.05522992776037 16.49 105.2395 /T 70.1/ 99.8 2014-Jun-14 00:00 226.67445 36.48623 0.06185310134867 16.55 111.4790 /T 71.3/ 98.9 2014-Jun-15 00:00 230.13093 31.89236 0.06915862364418 16.66 116.3552 /T 75.4/ 95.0 2014-Jun-16 00:00 232.67263 28.12584 0.07695559851688 16.79 120.1709 /T 81.9/ 88.6 2014-Jun-17 00:00 234.61758 25.01866 0.08511351395439 16.93 123.1715 /T 90.2/ 80.0 2014-Jun-18 00:00 236.15462 22.42887 0.09354338639554 17.08 125.5438 /T 99.5/ 69.9 2014-Jun-19 00:00 237.40202 20.24492 0.10218404962829 17.23 127.4274 /T 109.4/ 58.9 2014-Jun-20 00:00 238.43730 18.38134 0.11099292067989 17.38 128.9260 /T 119.3/ 47.6
Setups
We don't know what to expect for a bandwidth, so we're going to start with a standard CW setup. CW setup: --------------------------------------------------------------------------- TX polarization RCP RCV polarization LCP & RCP Frequency hops: no hopping Bandwidth: 4000 Hz TXoffset +500 Hz Sampling interval: 2500 x 0.1 usec FFT for PFS files: 8192 for 0.49 Hz resolution Ranging setups: --------------------------------------------------------------------------- 10-usec baud 10 usec code 127 PRP 1270 usec FFT 128 ncoh 1 bandwidth 787 Hz resolution 12.3 Hz TXOFF +100Hz (echo in bin 32 + 8 = 40) --------------------------------------------------------------------------- 11-usec baud 11 usec code 127 PRP 1397 usec FFT 64 ncoh 1 bandwidth 716 Hz resolution 11.2 Hz TXOFF +100 Hz (echo in bin 32 + 9= 41) ------------------------------------------------------------------------- 1-usec baud 1 usec code 255 FFT 512 ncoh 16 bandwidth 245 Hz resolution 0.48 Hz TXOFF +50 Hz ---------------------------------------------------------------------
Instructions
NOTE: Data should be moved to the appropriate subdirectories in aardvark:/export/data0/2002sr41/raw/
2002 SR41 POINTING:
OSOD and predicts will be on aardvark: ...not available yet... POINTING TX Offsets Date (UTC) DOY hhmmss RA Dec Macro LHA Dec RTT OSOD ... to be added ... Transmit offsets are given in millidegrees.
PRDX.OUT.14f-14-14.?? TRANSMITTER: STATION #14, RECEIVER: STATION #14 RECEIVER U.T. RANGE DOPPLER LHA DEC RA EL
2002 SR41 GOLDSTONE MASTERLOG
============================================================================== Receive TX Setup hops dwell code ncoh FFT runs start -stop OSOD offset Poln Notes ------------------------------------------------------------------------------
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 http://echo.jpl.nasa.gov/asteroids/2002SR41/2002SR41_planning.html
Asteroid Radar Astronomy