YU55 Tracking Plans DIRECT FROM GOLDSTONE. HOLY SHIT!

Background


Asteroid 2005 YU55 was discovered by Spacewatch on December 28, 2005.
It will approach Earth within 0.85 lunar distances (0.00217 AU) on
November 8, 2011, when it will be an extraordinarily strong radar target.
2005 YU55 has an absolute magnitude of 21.9, and imaging at Arecibo in 2010
revealed that the asteroid has a rounded shape with a diameter of about
400 meters.

The 2011 approach is the closest known by an asteroid with an absolute magnitude
this bright since 2010 XC15 (H = 21.4) approached within 0.5 lunar distances in 1976,
and until 2028, when 2001 WN5 (H = 18.2) will approach within 0.65 lunar distances,
and as such, it represents an invaluable scientific opportunity.
Our finest range resolution at Goldstone is 3.75 m,
which should reveal a wealth of detail about the asteroid's surface features,
shape, dimensions, and other physical properties.

The signal-to-noise ratios (SNRs) will be more than 1 million per round-trip time for
Goldstone observations on November 8-9.
As a result of the very high SNRs, we are planning to utilize the highest
resolution available from the chirp system, which should place thousands
of pixels on the object and reveal considerable surface detail. The radar
resolution will be orders of magnitude more detailed than is possible
with any ground- or space-based optical telescope and is comparable to
what can be obtained by a spacecraft flyby mission.

Due to the outstanding scientific potential presented by this event, we are
planning an extensive campaign of monostatic and bistatic radar observations
with Goldstone DSS-14, DSS-13, Arecibo, the Very Long Baseline Array, and the
Green Bank Telescope. The very short round-trip light travel times (only 2.2 seconds)
on dates surrounding the closest approach require that some observations will be bistatic.

On November 11 we will also conduct a brief intercontinental bistatic experiment
in which DSS-14 will transmit and our colleauges Stelio Montebugnoli, Guiseppe Pupillo,
and Emma Salerno will attempt to receive echoes with the 32 meter antenna at
Medicina, Italy (near Bologna).




Target Name: 2005 YU55
HMag: 21.9
Diameter: 0.4 km Based on Arecibo observations in 2010
Period: 18 h Based on Arecibo observations in 2010
OC radar albedo: 0.2 Based on Arecibo observations in 2010
subradar lat: 0 deg (a standard guess)
radar horizon: 20 deg

The best dates for Goldstone observations are between November 3-11.
Here are estimated monostatic signal-to-noise ratios at Goldstone. We
will need bistatic observations with reception at DSS-13 during the closest approach
on Nov 07-10. For bistatic observations, estimated monostatic SNRs
should be divided by 4.

Goldstone SNRs
UTC Distance # SNR/ SNR/
Date DOY Week Rise Set RA Dec AU runs date run
-------------------------------------------------------------​-------------
2011 Oct 30 303 43 16:37-23:15 221 -16 0.073 160 120 10
2011 Oct 31 304 44 16:33-23:12 221 -16 0.065 180 190 16
2011 Nov 01 305 44 16:30-23:10 221 -16 0.057 205 320 25
2011 Nov 02 306 44 16:28-23:08 222 -16 0.049 237 590 42
2011 Nov 03 307 44 16:25-23:07 222 -16 0.041 282 1200 79
2011 Nov 04 308 44 16:24-23:06 223 -16 0.033 347 2900 170
2011 Nov 05 309 44 16:23-23:09 224 -16 0.025 452 8500 440
2011 Nov 06 310 44 16:26-23:18 227 -15 0.017 645 39000 1700
2011 Nov 07 311 45 16:39-23:53 233 -14 0.009 1134 4.6E5 15000 Short RTT necessitates bistatic observations
2011 Nov 08-9 312-313 45 18:31-10:14 336 +17 0.002 4155 9.6E7 1.6E6 Short RTT necessitates bistatic observations
2011 Nov 10 314 45 01:00-11:38 27 +18 0.010 1520 3.8E5 11000 Short RTT necessitates bistatic observations
2011 Nov 11 315 45 01:27-11:50 33 +17 0.018 921 41000 1500
2011 Nov 12 316 45 01:34-11:53 35 +17 0.026 661 9900 420
2011 Nov 13 317 45 01:36-11:52 36 +17 0.034 516 3500 170
2011 Nov 14 318 46 01:35-11:51 37 +17 0.042 422 1500 79
2011 Nov 15 319 46 01:34-11:49 37 +17 0.050 357 760 43
2011 Nov 16 320 46 01:31-11:46 38 +17 0.058 310 420 26
2011 Nov 17 321 46 01:29-11:43 38 +17 0.066 273 250 16
2011 Nov 18 322 46 01:26-11:40 38 +17 0.074 244 160 11