2011 MD Goldstone Radar Observations Planning


Background


2011 MD was discovered on June 22, 2011 by LINEAR.  It will make one of the closest flybys
to Earth known on June 27 when it approaches within 0.000125 AU.  That's only about 1.9 Earth
radii above Earth's surface.   2011 MD has an absolute magnitude of 27.7, suggesting a diameter
within a factor of two of 10 meters.  Shortly after its discovery, this object appeared on the
NASA Near-Earth Object Program risk page and had a cumulative impact probability after 2020
of about 5%.  Subsequent astrometry reduced the impact probability by close to a factor
of ten and it is very likely that additional astrometry will reduce it even more.  This object
cannot hit Earth in 2011; even if it did, it would disintegrate harmlessly in the atmosphere.

The close approach is attracting media attention: articles have appeared online on skyandtelescope.com,
space.com, astronomy.com, spaceweather.com, and on the NASA Near-Earth Object Program 
website (neo.jpl.nasa.gov).

Nothing is known about the physical properties of this asteroid, but it's possible
that lightcurves and spectroscopy during June 25-29 will provide its rotation period 
and spectral class.

We have one 5.5 hour track on June 26 to observe this asteroid.
The round-trip time will be only two seconds so the observations will be 
bistatic with reception of echoes at DSS-13.  The maser is not available so we
will use the HEMT, which has a system temperature of about 80 K.

Due to the very short notice, we did not have time to obtain radiation clearance,
so we will transmit about 110 kW instead of the usual 450 kW.  Even with the 
lower transmitter power and warm system temperature, this object will be so close
that we should still get echoes.

We're going to start with CW observations with two hops.  What we do next
depends on how things go and whether or not we have any equipment problems.
 
Orbital and Physical Characteristics  
 orbit type               Apollo
 semimajor axis           1.030 AU     
 eccentricity             0.023
 inclination              3.2 deg
 perihelion distance      1.006 AU     
 aphelion distance        1.054 AU     
 absolute magnitude (H)   28.0
 diameter                 ~10 meters +- a factor of two 
 rotation period          unknown
 pole direction           unknown  
 lightcurve amplitude     unknown
 spectral class           unknown 

Last update: 2011 Jun 25

First MPEC

M.P.E.C. 2011-M23                                Issued 2011 June 23, 11:04 UT

     The Minor Planet Electronic Circulars contain information on unusual
         minor planets and routine data on comets.  They are published
   on behalf of Commission 20 of the International Astronomical Union by the
          Minor Planet Center, Smithsonian Astrophysical Observatory,
                          Cambridge, MA 02138, U.S.A.

             Prepared using the Tamkin Foundation Computer Network

                              MPC@CFA.HARVARD.EDU
            URL http://www.minorplanetcenter.net/    ISSN 1523-6714

                                    2011 MD

Observations:
     K11M00D* C2011 06 22.26489 16 52 05.99 +40 34 17.5          18.9  cEM023704
     K11M00D  C2011 06 22.27521 16 51 58.24 +40 33 54.6          19.2  cEM023704
     K11M00D  C2011 06 22.29608 16 51 42.63 +40 32 58.8          19.4  cEM023704
     K11M00D  C2011 06 22.30667 16 51 34.94 +40 32 28.1          19.3  cEM023704
     K11M00D KC2011 06 23.07075 16 49 19.28 +39 58 56.4                uEM023J95
     K11M00D KC2011 06 23.07233 16 49 18.43 +39 58 48.3                uEM023J95
     K11M00D KC2011 06 23.07752 16 49 15.43 +39 58 22.8          18.3 RuEM023J95
     K11M00D KC2011 06 23.19989216 50 03.62 +40 02 28.8          18.5 RuEM023H36
     K11M00D KC2011 06 23.20205516 50 01.78 +40 02 24.9          18.4 RuEM023H36
     K11M00D KC2011 06 23.20428016 49 59.86 +40 02 20.5          18.4 RuEM023H36
     K11M00D KC2011 06 23.20646216 49 57.97 +40 02 16.3          18.6 RuEM023H36
     K11M00D |C2011 06 23.21662 16 50 09.20 +40 04 30.0                cEM023H06
     K11M00D |C2011 06 23.21791 16 50 08.04 +40 04 28.0                cEM023H06
     K11M00D |C2011 06 23.21919 16 50 06.85 +40 04 25.5          17.9 RcEM023H06
     K11M00D  C2011 06 23.26779 16 49 32.80 +40 02 54.0          19.1 RcEM023854
     K11M00D  C2011 06 23.27072 16 49 30.10 +40 02 47.4          18.7 RcEM023854
     K11M00D  C2011 06 23.27366 16 49 27.23 +40 02 35.8          19.1 RcEM023854

Observer details:
704 Lincoln Laboratory ETS, New Mexico.  Observers M. Blythe, G. Spitz,
    R. Brungard, J. Paige, P. Festler, T. McVey, A. Valdivia.  1.0-m f/2.15
    reflector + CCD.
854 Sabino Canyon Observatory, Tucson.  Observer J. E. McGaha.  0.36-m f/10.0
    Schmidt-Cassegrain + CCD.
H06 RAS Observatory, Mayhill.  Observer H. Sato.  0.25-m f/3.4 reflector + CCD.
H36 Sandlot Observatory, Scranton.  Observer G. Hug.  0.56-m reflector + CCD.
J95 Great Shefford.  Observer P. Birtwhistle.  0.40-m f/6.0 Schmidt-Cassegrain
    + CCD.

Orbital elements:
2011 MD                                                  Earth MOID = 0.0006 AU
Epoch 2011 Aug. 27.0 TT = JDT 2455800.5                 MPC
M  51.54504              (2000.0)            P               Q
n   0.90091518     Peri.    6.12962     +0.15113548     +0.98754135
a   1.0617284      Node   272.56906     -0.90879587     +0.12137078
e   0.0431456      Incl.    2.51400     -0.38890632     +0.10015593
P   1.09           H   27.7           G   0.15           U   3
Residuals in seconds of arc
110622 704  0.4+  0.3+    110623 J95  0.1-  0.0     110623 H06 (0.4+  3.8+)
110622 704  0.4+  0.2-    110623 H36  0.7-  0.4+    110623 H06 (0.1+  3.2+)
110622 704  0.8-  0.8-    110623 H36  0.5-  0.5+    110623 854  0.3+  0.3+
110622 704  0.3-  1.3+    110623 H36  0.5-  0.4+    110623 854  0.8+  1.8+
110623 J95  0.1+  0.1-    110623 H36  0.6-  0.6+    110623 854  0.6-  1.3-
110623 J95  0.7+  0.4-    110623 H06 (0.3+  4.0+)

Ephemeris:
2011 MD                  a,e,i = 1.06, 0.04, 3                   q = 1.0159
Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase     V
...
2011 06 23    16 50 26.8 +40 09 21   0.0057611.0187   114.1    65.6    18.9
2011 06 24.00 16 47 04.1 +39 25 25   0.0046941.0183   114.3    65.4    18.4
2011 06 24.20 16 46 12.3 +39 13 52   0.0044771.0183   114.4    65.4    18.3
2011 06 24.40 16 45 15.3 +39 01 03   0.0042581.0182   114.5    65.3    18.2
2011 06 24.60 16 44 12.4 +38 46 44   0.0040371.0181   114.6    65.2    18.1
2011 06 24.80 16 43 02.6 +38 30 39   0.0038141.0180   114.7    65.1    17.9
2011 06 25.00 16 41 44.5 +38 12 26   0.0035881.0180   114.8    65.0    17.8
2011 06 25.20 16 40 16.6 +37 51 37   0.0033601.0179   114.9    64.9    17.7
2011 06 25.40 16 38 36.7 +37 27 36   0.0031291.0178   115.1    64.8    17.5
2011 06 25.60 16 36 42.0 +36 59 33   0.0028951.0177   115.3    64.6    17.3
2011 06 25.80 16 34 28.6 +36 26 16   0.0026571.0177   115.5    64.3    17.1
2011 06 26.00 16 31 50.9 +35 46 05   0.0024141.0176   115.8    64.1    16.9
2011 06 26.20 16 28 41.1 +34 56 24   0.0021661.0175   116.2    63.7    16.7
2011 06 26.40 16 24 46.6 +33 53 08   0.0019111.0174   116.7    63.2    16.4
2011 06 26.60 16 19 47.1 +32 29 11   0.0016471.0173   117.3    62.7    16.0
2011 06 26.80 16 13 05.4 +30 31 05   0.0013731.0172   118.1    61.9    15.6
2011 06 27.00 16 03 25.0 +27 29 10   0.0010831.0171   119.3    60.7    15.1
2011 06 27.20 15 47 25.7 +21 59 27   0.0007691.0170   121.1    58.9    14.3
2011 06 27.40 15 10 41.5 +07 23 40   0.0004131.0168   123.9    56.1    12.9
2011 06 27.60 03 44 48.2 -21 01 03   0.0001581.0165    58.9   121.1    13.7
2011 06 27.80 01 25 20.1 +33 03 02   0.0005471.0164    65.3   114.7    15.9
2011 06 28.00 00 49 25.3 +41 46 35   0.0008851.0163    70.4   109.5    16.6
2011 06 28.20 00 29 28.3 +45 32 37   0.0011891.0163    73.1   106.9    17.1
2011 06 28.40 00 16 10.6 +47 41 47   0.0014731.0162    74.7   105.2    17.5
2011 06 28.60 00 06 28.7 +49 06 25   0.0017431.0162    76.0   104.0    17.8
2011 06 28.80 23 59 00.2 +50 06 39   0.0020031.0162    76.9   103.0    18.0
2011 06 29.00 23 53 00.9 +50 51 56   0.0022551.0162    77.6   102.3    18.2
2011 06 29.20 23 48 05.0 +51 27 22   0.0025011.0161    78.2   101.6    18.4
...

Gareth V. Williams           (C) Copyright 2011 MPC           M.P.E.C. 2011-M23


SNR Calculation

Target Name:    2011 MD
HMag:           27.6
Diameter:       10 meters  an educated guess
Period:         0.5 hours  an educated guess

                                                #                 max

2011MD:  D = 0.01 km,  P = 0.5000 hr,  OC albedo = 0.100

Goldstone:  G =  0.94 K/Jy,  Tsys = 18.0 K,  P = 450 kW,  elev >= 20.00 deg,  unhopped
            t_down = 0 s,    t_switch = 0 s

                                             #                 max
 start date    window      RA, dec   dist   runs        SNR   SNR/RTT
2011 Jun 25  00:17-12:12  250, +38  0.003   6548        150         2
2011 Jun 26  00:12-11:43  247, +35  0.002   9725        810         9 
2011 Jun 27  00:07-09:58  239, +25  0.001  20000      26000       200 
2011 Jun 27  17:56-20:16   36,  -3  0.000  20000   47000000     38000
2011 Jun 28  07:35-19:57    3, +49  0.001  16766       4800        40 
2011 Jun 29  06:18-19:43  354, +53  0.003   9474        430         5
2011 Jun 30  05:46-19:33  351, +54  0.004   6786        110         1

Goldstone SNRs assume Ptx = 115 kW, reception at DSS-13, and Tsys = 80 K

Track Assignments


Goldstone track:

        UT          UT          PST                     Duration  Round-trip
DOY     Date        TX Window   TX Window               hh:mm     time (sec)  SNR/Run 
---     ----        ---------   ---------               --------- -------     -------
177     Jun 26      0530-1100   2230-0400 Jun 25-26      5:30      2            9


Uncertainties


From Jon Giorgini, 2011 Jun 26
Solution 6
With 137 optical measurements (2011-Jun-22 to 2011-Jun-25), 
including 10 measurements from Michael Hicks at Table Mountain 
after the DOU (and clean-up of site-biased outlier data),
2011 MD orbit solution #6 was estimated.

Formal 3-sigma uncertainties are shown below. Pointing knowledge 
is secure for the radar experiment.

 Date__(UT)__HR:MN   POS_3sigma   DOP_X_3sig  RT_delay_3sig
 2011-Jun-26 05:30        6.521        61.51       0.001350
 2011-Jun-26 06:00        6.932        61.51       0.001351
 2011-Jun-26 06:30        7.382        61.53       0.001352
 2011-Jun-26 07:00        7.870        61.55       0.001353
 2011-Jun-26 07:30        8.394        61.58       0.001355
 2011-Jun-26 08:00        8.952        61.61       0.001357
 2011-Jun-26 08:30        9.541        61.66       0.001358
 2011-Jun-26 09:00       10.158        61.72       0.001360
 2011-Jun-26 09:30       10.799        61.79       0.001363
 2011-Jun-26 10:00       11.463        61.87       0.001365
 2011-Jun-26 10:30       12.145        61.97       0.001368
 2011-Jun-26 11:00       12.844        62.09       0.001371

Differencing predictions for orbit solution #6 with the prior solution #2 ...
(at the start of the DSS-14 -> 13 bistatic experiment)

   TRANSMITTER: STATION #14,     RECEIVER: STATION #13
   RECEIVER    U.T.         RANGE         DOPPLER     LHA      DEC      RA      EL     
s6: 2011 JUN 26 05:30      2.2277441286   122173.137 352.0759  35.1119 247.631  83.524
s2: 2011 JUN 26 05:30      2.2281117647   122152.050 352.0750  35.1127 247.632  83.523
                           ------------   ----------           ------- ------- 
                          -0.000367636 s      21.087 Hz        RSS of 4.6"

... so there was a +0.2-sigma shift in pointing, a +0.2-sigma shift in Doppler,
and a -0.15-sigma shift in round-trip time, relative to the prior solution.

So orbit s6 is well within the uncertainties of prior orbit solution #2
and, while they aren't totally independent results, indicate statistics 
for s6 should be reliable and that we would have been "OK" going with 
predictions based on orbit s2.

- - - - - - - - - - - - - - - - -

From Jon Giorgini, 2011 June 24:
With 56 measurements (2011-Jun-22 to 2011-Jun-24), 3-sigma
uncertainties are:
 
 Date__(UT)__HR:MN   POS_3sigma  DOP_S_3sig  DOP_X_3sig  RT_delay_3sig
 2011-Jun-25 00:00        7.442       76.96      275.28       0.004680
 2011-Jun-25 12:00       23.064       79.01      282.61       0.005617
 2011-Jun-26 00:00       44.493       84.47      302.14       0.006804
 2011-Jun-26 12:00      129.561       99.21      354.85       0.008226
 2011-Jun-27 00:00      351.339      155.33      555.57       0.010206
 2011-Jun-27 12:00     3416.609      792.35     2833.98       0.013692
 2011-Jun-28 00:00     1943.678      423.56     1514.93       0.013759
 2011-Jun-28 12:00      589.193       66.27      237.04       0.011918
 2011-Jun-29 00:00      540.301       45.96      164.37       0.011751

Differencing s2-s1:

   TRANSMITTER: STATION #14,     RECEIVER: STATION #14
   RECEIVER    U.T.         RANGE         DOPPLER     LHA      DEC      RA      EL     
s2: 2011 JUN 26 04:10      2.2981224810   127402.057 331.3577  35.2852 248.200  66.722
s1: 2011 JUN 26 04:10      2.1494378465   132398.396 331.6348  34.9606 247.923  66.895
                           ------------   ----------           ------- -------
                           0.148685        -4996.34             0.3246   0.277

(-2.75 sigma doppler, 3-sigma delay, 3-sigmas pointing)

Considering the short s1 arc (17 measurements, 1 day) with some 
outlier measurements now obviously off more than their assigned 
uncertainty (measurement bias/error), the shift seems OK and 
will be less in the future.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

From Jon Giorgini, 2011 June 23:

Solution 1 uncertainties:

Uncertainties are high (12-hour output below); more 
astrometry is needed to support pointing:

 Date__(UT)__HR:MN   POS_3sigma  DOP_S_3sig  DOP_X_3sig  RT_delay_3sig
 2011-Jun-25 00:00      246.989     1196.07     4277.97       0.092523
 2011-Jun-25 12:00      633.243     1265.54     4526.45       0.114443
 2011-Jun-26 00:00     1169.394     1423.79     5092.46       0.138354
 2011-Jun-26 12:00     3331.609     1839.74     6580.18       0.165629
 2011-Jun-27 00:00    10201.984     3595.82    12861.14       0.206386
 2011-Jun-27 12:00   328858.072    85309.63   305126.21       0.246211
 2011-Jun-28 00:00    15132.431     3511.71    12560.31       0.237290
 2011-Jun-28 12:00     1625.939      428.59     1532.94       0.217070
 2011-Jun-29 00:00     2639.231      303.15     1084.27       0.216485


Setups


We don't know the rotation period but there are preliminary indications that 
the rotation period may be only minutes.  The CW setup below is a standard
placeholder; we'll update it if the asteroid's rotation period becomes available
before the track.

The Doppler uncertainties are already small enough that a bandwidth of 4 kHz
will be fine.

CW setup:
---------------------------------------------------------------------------
TX polarization           RCP
RCV polarization          LCP  (the HEMT at DSS-13 cannot receive both channels)
Frequency hops:           2                          
Dwell                     30 seconds                      
Bandwidth:                4000 Hz 
Sampling interval:        2500 x 0.1 usec
VME FFT for PSD files:    4096 for 0.98-Hz resolution 

Ranging setups:
---------------------------------------------------------------------------
127 x 64 10-usec single sample
baud             10 usec
code            127
gates           127
PRP            1270 usec
FFT              64   
CLT       VME     ?
          PFS     ?
ncoh              4
bandwidth        196.9 Hz   
resolution       3.1 Hz
TXOFF          +50 Hz -> echo will be centered at +16 bins or in bin 32 + 16 = 48
---------------------------------------------------------------------------
127 x 64 11-usec single sample
baud             11 usec
code            127
gates           127
PRP            1397 usec
FFT              64  
CLT       VME     ?
          PFS     ?
ncoh              4
bandwidth        179.0  Hz   
resolution       2.8  Hz
TXOFF          +50 Hz --> echo will be centered at +18 bins or in bin 32 + 18 = 50
-------------------------------------------------------------------------
1-usec single sample
baud              1 usec
code              127
ncoh              20
bandwidth         393.7  Hz
FFT               128
dfreq             3.1  Hz
TXoff            +50 Hz  (echo in bin 64+16 =80)
-------------------------------------------------------------------------------
0.25-usec imaging  
baud            0.25 usec
code            127
FFT             128
ncoh            246
bandwidth       128 Hz    
resolution      1.00 Hz
TXOFF          +20  Hz, echo is in bin 64+20=84 
--------------------------------------------------------------------------
0.125-usec 
------------ 
baud           0.125 usec
code           255  
FFT            256 
ncoh           122
bandwidth      257.15 Hz      
resolution     1.0045 Hz
TXOFF          +30 Hz to put echo at 128 + 30 = bin 158 

_____________________________________________________________________
POSSIBLE RANGING SETUPS: (code=127, FFT=64, single-pol'n) 
   These are from JX, w/ max-band (min-acc) options from Ray Jurgens.
   Currently configured for 5-sec records.
_______________________________________________________________________
 Setup        Baud        RP         1-acc 1-acc      
            usec   m      usec        band   res    acc  band     res 
_______________________________________________________________________
 
JX1XS110  11.000 1650    1397.0      715.8  11.2      2   358     5.6
JX1XS070   7.000 1050     889.0     1124.9  17.6      3   375     5.9
                                                      
JX1XS020   2.000  300     254.0     3937.0  61.5     12   328     5.1
                                                      4   984    15.4 

JX1XS010   1.000  150     127.0     7874.0 123.0     41   192     3.0 
                                                      8   984    15.4 

JX1XS005   0.500   75      63.5    15748.0 246.1    123   128     2.0 
                                                     15  1050    16.4 

JX1XS002   0.250   37.5    31.75   31496.1 492.1    492    64     1.0
                                                     30  1050    16.4 
 
JX1XS001   0.125   18.75   15.875  62992.1 984.3   1970    32     0.5 
                                                     60  1050    16.4 
____________________________________________________________________


Instructions

NOTE: Data should be moved to the appropriate subdirectories in aardvark:/export/data0/2011MD/raw/

2011 MD POINTING:

  OSOD and predicts are on aardvark:

/export/data3/osod/ops/2011MD/PRDX.OUT.14v-13-13.bist.s2
                             /PUNCH.OUT.14v-13-13.bist.s2
                             /EPH.OUT.s2


POINTING  

                                                          TX Offsets    
Date (UTC)   DOY  hhmmss    RA        Dec    Macro   LHA     Dec    RTT    OSOD
2011 06 26  177   050000   247.8546 35.1838   A                     2.25    2
2011 06 26        060000   247.4059 35.0237   A      0.3  -0.1      2.20 
2011 06 26        070000   246.9378 34.8179   AB                    2.15
2011 06 26        080000   246.4713 34.5650    B     0.3  -0.1      2.11 
2011 06 26        090000   246.0275 34.2664    BC                   2.06
2011 06 26        100000   245.6258 33.9262     C    0.2  -0.2      2.01 
2011 06 26        110000   245.2822 33.5509     C                   1.97


Macro with Solution 6:
2011 06 26  177   060000   247.4049 35.0228  A                              6
2011 06 26        070000   246.9367 34.8169  AB   0.3  -0.1   
2011 06 26        080000   246.4701 34.5639  AB   0.3  -0.2   
2011 06 26        090000   246.0262 34.2652   BC 
2011 06 26        100000   245.6243 33.9249    C  0.2  -0.2   
2011 06 26        110000   245.2805 33.5495    C  

Transmit offsets are given in millidegrees.  


Due to the decreasing round-trip light travel time, the SNR/RTT will increase
by about 60% during the track.


PRDX.OUT.s??? TRANSMITTER: STATION #14, RECEIVER: STATION #13 RECEIVER U.T. RANGE DOPPLER LHA DEC RA EL ...We will post this on June 26 after the orbit solution improves again...

2011 MD 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 300-233 | FAX: (818) 354-9476 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/2011MD/2011MD_planning.html

Asteroid Radar Astronomy
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