Monday, April 30, 2012

Near-Earth Objects, Part Six



Near-Earth Asteroid Discovery Statistics


Data Compiled by Alan B. Chamberlin of NASA/Jet Propulsion Laboratory

The charts and tables below show the number of near-Earth asteroids (NEAs) discovered by each of the predominant search programs within each half-year interval. There are two sets of charts and tables. The first set shows statistics for all NEAs while the second set shows statistics for only large NEAs. In this context, "large" is defined as NEAs with absolute magnitudes (H) of 18.0 or brighter. This roughly corresponds to 1 km diameter and larger NEAs.

All Asteroids
NEAs Discovered by Site

Half Year
Intervals
LINEAR
(704)
NEAT
(566,608,644)
Spacewatch
(691,291)
LONEOS
(699)
Catalina
(703,E12,G96)
Pan-STARRS
(F51)
OtherCumulative
Total
 1995 (1)00140004334
 1995 (2)00120002348
 1996 (1)15180004376
 1996 (2)05100002393
 1997 (1)32100004412
 1997 (2)14940007446
 1998 (1)449191107527
 1998 (2)922166205650
 1999 (1)7401261101754
 1999 (2)870771903877
 2000 (1)1082142113041039
 2000 (2)1501312170081239
 2001 (1)95287220021393
 2001 (2)1846415200041680
 2002 (1)1585616141061931
 2002 (2)12889670052166
 2003 (1)1023023330092363
 2003 (2)1333833218082604
 2004 (1)16719411425062876
 2004 (2)1377292560063140
 2005 (1)78828221160103402
 2005 (2)593054191930103767
 2006 (1)4444513197034073
 2006 (2)5218547200054409
 2007 (1)384207200034681
 2007 (2)740255266075058
 2008 (1)740431281055462
 2008 (2)6704302780115861
 2009 (1)5003202620186223
 2009 (2)5803103140176643
 2010 (1)2902102570987048
 2010 (2)75022034518527560
 2011 (1)40017033368148032
 2011 (2)300150253105238458
 2012 (1)*1901202669148850
* Incomplete half-year (based on discovery data through 2012-Apr-29 06:05 local)


Large Asteroids
Large NEAs Discovered by Site

Half Year
Intervals
LINEAR
(704)
NEAT
(566,608,644)
Spacewatch
(691,291)
LONEOS
(699)
Catalina
(703,E12,G96)
Other
Cumulative
Total
 1995 (1)
0
0
3
0
0
2
192
 1995 (2)
0
0
4
0
0
1
197
 1996 (1)
0
2
2
0
0
0
201
 1996 (2)
0
2
0
0
0
0
203
 1997 (1)
0
1
3
0
0
1
208
 1997 (2)
3
4
1
0
0
2
218
 1998 (1)
9
4
2
1
0
2
236
 1998 (2)
27
2
1
3
0
3
272
 1999 (1)
21
0
2
5
4
0
304
 1999 (2)
27
0
1
2
3
2
339
 2000 (1)
35
2
2
2
5
1
386
 2000 (2)
43
2
3
6
0
4
444
 2001 (1)
28
10
0
5
0
0
487
 2001 (2)
31
10
0
5
0
1
534
 2002 (1)
41
5
2
3
0
3
588
 2002 (2)
26
15
0
1
0
2
632
 2003 (1)
19
4
2
6
0
1
664
 2003 (2)
21
6
2
4
2
1
700
 2004 (1)
18
5
1
2
4
1
731
 2004 (2)
10
1
0
1
14
0
757
 2005 (1)
13
1
2
1
11
1
786
 2005 (2)
6
8
5
2
12
1
820
 2006 (1)
3
0
2
1
11
1
838
 2006 (2)*
0
0
0
0
1
0
839
* Incomplete half-year (based on discovery data through 2006-Jul-07 06:00 local)


Number of NEOs

NASA's search program designed to discover 90% of the NEO population (1 km in diameter or larger) within 10 years is under way. The chart below shows the cumulative total known near-Earth asteroids versus time. The blue area shows all near-Earth asteroids while the red area shows only large near-Earth asteroids (those with diameters roughly one kilometer and larger).



The chart below shows the total known near-Earth asteroids per size bin. Diameters are estimated using an assumed average albedo for NEAs. The first size bin represents NEAs smaller than 30m in diameter. The second represents NEAs with diameters from 30m to 100m, and so on. Data shown in the chart represent known NEAs as of the date shown in the bottom-right corner of the chart.



The table below shows the total number of NEOs known at selected dates. The most recent date at the top of the table is generally not the date the table was updated, but rather the discovery date of the most recently discovered NEO. This table is updated daily using discovery data published by the Minor Planet Center. "NEC" are Near-Earth comets. "PHA-KM" and "NEA-KM" are PHAs and NEAs with diameters roughly one kilometer and larger. Other definitions, such as Apollo, are on the NEO groups page.

------------------------------------------------------------------------
   Date      NEC  Atira Aten Apollo Amor  PHA-KM  PHA  NEA-KM  NEA   NEO
----------  ----  ----- ---- ------ ----  ------ ----  ------ ----  ----
2012-04-27    91     11  702   4811 3326     152 1303     840 8850  8941
2012-04-01    91     11  701   4770 3302     152 1299     839 8784  8875
2012-03-01    91     11  695   4690 3275     152 1292     838 8671  8762
2012-02-01    91     11  686   4642 3234     152 1285     838 8573  8664
2012-01-01    91     11  676   4572 3199     152 1277     837 8458  8549
2011-12-01    91     11  672   4540 3174     152 1270     833 8397  8488
2011-11-01    91     11  669   4499 3139     150 1260     830 8318  8409
2011-10-01    91     11  662   4437 3094     149 1248     829 8204  8295
2011-09-01    90     11  661   4402 3039     149 1242     827 8113  8203
2011-08-01    90     11  661   4386 3013     149 1239     826 8071  8161
2011-07-01    89     11  659   4373 2989     149 1235     826 8032  8121
2011-06-01    89     11  659   4356 2963     149 1230     825 7989  8078
2011-05-01    89     11  656   4329 2942     149 1220     824 7938  8027
2011-04-01    89     11  645   4279 2912     149 1213     823 7847  7936
2011-03-01    89     11  634   4216 2888     149 1203     821 7749  7838
2011-02-01    89     11  624   4169 2870     149 1192     821 7674  7763
2011-01-01    89     11  618   4093 2838     149 1176     819 7560  7649
2010-12-01    89     10  609   4038 2806     149 1167     818 7463  7552
2010-11-01    89     10  598   3969 2760     149 1161     818 7337  7426
2010-10-01    89     10  588   3913 2720     149 1147     818 7231  7320
2010-09-01    89     10  582   3867 2655     149 1142     817 7114  7203
2010-08-01    89     10  579   3853 2645     149 1139     815 7087  7176
2010-07-01    89     10  574   3831 2633     149 1137     813 7048  7137
2010-06-01    88     10  568   3800 2610     149 1129     812 6988  7076
2010-05-01    87     10  560   3757 2590     148 1116     810 6917  7004
2010-04-01    87     10  552   3710 2574     148 1110     810 6846  6933
2010-03-01    87     10  544   3673 2549     148 1101     810 6776  6863
2010-02-01    87     10  540   3619 2524     147 1089     808 6693  6780
2010-01-01    87     10  535   3593 2505     147 1086     806 6643  6730
2009-12-01    87     10  531   3572 2495     147 1081     804 6608  6695
2009-11-01    86     10  520   3496 2467     147 1073     801 6493  6579
2009-10-01    86     10  511   3441 2434     147 1069     799 6396  6482
2009-09-01    86     10  506   3388 2387     147 1059     797 6291  6377
2009-08-01    86     10  504   3368 2360     147 1057     796 6242  6328
2009-07-01    86     10  504   3358 2351     146 1055     792 6223  6309
2009-06-01    85     10  501   3345 2341     145 1052     791 6197  6282
2009-05-01    85     10  499   3318 2328     145 1043     790 6155  6240
2009-04-01    85     10  496   3286 2314     145 1039     788 6106  6191
2009-03-01    85     10  491   3224 2295     145 1027     788 6020  6105
2009-02-01    85     10  487   3167 2268     144 1015     785 5932  6017
2009-01-01    85     10  481   3122 2248     144 1006     783 5861  5946
2008-12-01    84     10  480   3080 2218     144  996     782 5788  5872
2008-11-01    84     10  474   3032 2196     144  987     780 5712  5796
2008-10-01    84      9  467   2971 2146     143  977     779 5593  5677
2008-09-01    83      9  464   2940 2112     143  967     778 5525  5608
2008-08-01    83      9  461   2925 2098     143  961     777 5493  5576
2008-07-01    83      9  459   2907 2087     142  952     774 5462  5545
2008-06-01    83      9  455   2896 2079     142  949     773 5439  5522
2008-05-01    83      9  451   2866 2062     142  943     773 5388  5471
2008-04-01    83      9  449   2819 2033     142  940     772 5310  5393
2008-03-01    83      8  440   2751 2008     141  930     765 5207  5290
2008-02-01    83      8  428   2692 1977     140  916     763 5105  5188
2008-01-01    83      8  426   2664 1960     140  907     763 5058  5141
2007-12-01    83      8  423   2629 1943     140  898     760 5003  5086
2007-11-01    83      8  411   2571 1907     140  888     756 4897  4980
2007-10-01    82      8  397   2522 1865     140  877     755 4792  4874
2007-09-01    82      8  390   2484 1833     139  870     754 4715  4797
2007-08-01    82      8  388   2473 1823     138  865     750 4692  4774
2007-07-01    82      8  388   2469 1816     138  864     750 4681  4763
2007-06-01    82      8  383   2447 1807     137  855     747 4645  4727
2007-05-01    82      8  382   2435 1795     137  851     745 4620  4702
2007-04-01    82      8  381   2410 1778     137  847     741 4577  4659
2007-03-01    82      7  375   2371 1754     137  840     739 4507  4589
2007-02-01    82      7  367   2338 1738     136  832     735 4450  4532
2007-01-01    82      7  359   2318 1725     136  823     734 4409  4491
2006-12-01    81      7  354   2291 1707     136  820     732 4359  4440
2006-11-01    81      6  344   2242 1683     135  808     725 4275  4356
2006-10-01    79      6  337   2212 1651     135  798     723 4206  4285
2006-09-01    79      6  330   2176 1622     134  789     719 4134  4213
2006-08-01    79      6  328   2159 1609     134  784     719 4102  4181
2006-07-01    79      6  327   2148 1592     134  782     718 4073  4152
2006-06-01    79      6  326   2137 1579     134  779     718 4048  4127
2006-05-01    79      5  325   2109 1552     134  769     714 3991  4070
2006-04-01    78      5  321   2082 1537     134  759     712 3945  4023
2006-03-01    78      5  319   2066 1518     134  758     711 3908  3986
2006-02-01    78      5  316   2031 1501     134  750     708 3853  3931
2006-01-01    78      5  312   1976 1474     133  741     703 3767  3845
2005-12-01    78      5  302   1944 1453     132  730     700 3704  3782
2005-11-01    77      5  297   1902 1427     131  720     695 3631  3708
2005-10-01    76      4  289   1846 1387     130  708     684 3526  3602
2005-09-01    76      4  286   1812 1368     130  703     681 3470  3546
2005-08-01    76      4  283   1798 1352     130  697     679 3437  3513
2005-07-01    76      4  279   1779 1340     129  690     676 3402  3478
2005-06-01    76      4  275   1764 1320     129  686     671 3363  3439
2005-05-01    75      4  274   1747 1305     127  680     668 3330  3405
2005-04-01    75      4  268   1722 1286     125  667     664 3280  3355
2005-03-01    75      4  263   1681 1262     124  657     660 3210  3285
2005-02-01    75      4  262   1657 1255     123  653     657 3178  3253
2005-01-01    75      4  258   1633 1245     123  646     653 3140  3215
2004-12-01    74      3  249   1601 1224     123  637     645 3077  3151
2004-11-01    74      3  245   1581 1218     122  628     640 3047  3121
2004-10-01    73      3  238   1553 1210     121  617     638 3004  3077
2004-09-01    72      3  230   1515 1185     121  609     637 2933  3005
2004-08-01    72      3  226   1496 1162     120  602     633 2887  2959
2004-07-01    72      3  226   1490 1157     118  599     630 2876  2948
2004-06-01    72      3  223   1460 1144     117  588     627 2830  2902
2004-05-01    72      2  218   1441 1129     117  582     623 2790  2862
2004-04-01    72      2  215   1411 1117     113  572     616 2745  2817
2004-03-01    72      2  206   1375 1099     113  565     607 2682  2754
2004-02-01    71      2  204   1360 1092     112  560     606 2658  2729
2004-01-01    71      2  202   1326 1074     110  550     602 2604  2675
2003-12-01    71      2  196   1294 1062     107  538     594 2554  2625
2003-11-01    71      2  193   1272 1049     107  530     588 2516  2587
2003-10-01    71      2  188   1245 1027     107  521     586 2462  2533
2003-09-01    71      2  185   1225  993     105  512     579 2405  2476
2003-08-01    71      2  185   1213  980     102  507     575 2380  2451
2003-07-01    70      2  184   1206  971     102  504     572 2363  2433
2003-06-01    70      2  182   1190  959     102  499     566 2333  2403
2003-05-01    68      2  180   1176  953     101  497     564 2311  2379
2003-04-01    68      2  175   1156  942     101  490     559 2275  2343
2003-03-01    68      2  170   1137  931     101  483     555 2240  2308
2003-02-01    68      1  169   1117  925     101  478     551 2212  2280
2003-01-01    68      1  167   1090  908     100  468     544 2166  2234
2002-12-01    68      1  163   1063  888     100  466     542 2115  2183
2002-11-01    68      1  160   1048  871      99  460     538 2080  2148
2002-10-01    67      1  158   1024  848      98  454     529 2031  2098
2002-09-01    65      1  155   1004  829      97  448     521 1989  2054
2002-08-01    65      1  154    988  806      95  437     517 1949  2014
2002-07-01    64      1  152    978  800      94  430     512 1931  1995
2002-06-01    64      1  148    960  792      92  421     506 1901  1965
2002-05-01    64      1  144    942  781      91  412     495 1868  1932
2002-04-01    64      1  142    924  768      91  405     493 1835  1899
2002-03-01    63      1  136    897  754      90  395     489 1788  1851
2002-02-01    63      1  131    874  738      89  386     479 1744  1807
2002-01-01    63      1  124    840  715      89  373     470 1680  1743
2001-12-01    63      1  121    804  696      85  359     461 1622  1685
2001-11-01    61      1  120    776  681      83  351     456 1578  1639
2001-10-01    61      1  114    750  658      82  341     452 1523  1584
2001-09-01    61      1  110    721  623      81  330     439 1455  1516
2001-08-01    60      1  109    699  603      81  324     437 1412  1472
2001-07-01    59      1  108    694  590      81  323     436 1393  1452
2001-06-01    58      1  108    684  579      79  320     429 1372  1430
2001-05-01    57      1  107    672  568      77  313     421 1348  1405
2001-04-01    57      1  105    660  559      76  304     417 1325  1382
2001-03-01    57      1  101    645  545      74  295     409 1292  1349
2001-02-01    57      1   98    634  534      73  292     404 1267  1324
2001-01-01    57      1   94    619  525      73  289     400 1239  1296
2000-12-01    57      1   93    605  513      72  283     393 1212  1269
2000-11-01    57      1   90    581  496      71  280     384 1168  1225
2000-10-01    57      1   87    571  482      71  276     376 1141  1198
2000-09-01    57      1   81    553  456      70  270     367 1091  1148
2000-08-01    57      1   79    535  440      68  261     358 1055  1112
2000-07-01    57      1   77    530  431      66  258     347 1039  1096
2000-06-01    57      1   76    525  425      65  254     344 1027  1084
2000-05-01    57      1   76    512  411      65  249     338 1000  1057
2000-04-01    56      1   73    497  398      64  243     331  969  1025
2000-03-01    56      1   64    481  387      62  231     319  933   989
2000-02-01    56      1   62    464  376      62  221     312  903   959
2000-01-01    56      1   57    450  369      62  215     307  877   933
1999-12-01    55      1   56    440  360      60  207     299  857   912
1999-11-01    55      1   54    427  346      60  203     289  828   883
1999-10-01    55      1   54    411  332      59  198     284  798   853
1999-09-01    53      1   54    394  317      58  192     280  766   819
1999-08-01    53      1   54    394  315      58  192     280  764   817
1999-07-01    53      1   54    389  310      57  190     276  754   807
1999-06-01    53      1   51    382  300      56  185     273  734   787
1999-05-01    52      1   49    370  295      52  177     264  715   767
1999-04-01    52      1   48    357  288      51  173     256  694   746
1999-03-01    52      1   47    347  283      51  172     255  678   730
1999-02-01    52      1   47    337  278      51  169     252  663   715
1999-01-01    52      1   45    332  272      51  166     250  650   702
1998-12-01    52      1   41    322  263      51  162     241  627   679
1998-11-01    52      1   38    307  254      49  154     236  600   652
1998-10-01    52      1   36    302  248      49  152     232  587   639
1998-09-01    52      1   29    289  235      48  140     226  554   606
1998-08-01    52      1   29    279  224      46  133     220  533   585
1998-07-01    52      1   29    276  221      44  129     217  527   579
1998-06-01    52      1   29    270  214      43  127     213  514   566
1998-05-01    52      1   29    261  208      43  124     209  499   551
1998-04-01    52      1   27    253  199      43  117     208  480   532
1998-03-01    52      1   27    242  190      43  112     204  460   512
1998-02-01    52      0   26    238  190      42  110     203  454   506
1998-01-01    52      0   26    233  187      42  108     200  446   498
1997-01-01    52      0   22    204  167      40   97     188  393   445
1996-01-01    52      0   20    177  151      38   86     182  348   400
1995-01-01    52      0   19    163  134      37   83     172  316   368
1994-01-01    50      0   15    140  115      33   70     155  270   320
1993-01-01    50      0   13    117   99      31   64     141  229   279
1992-01-01    50      0   11    103   85      29   61     124  199   249
1991-01-01    48      0    9     76   74      24   49     106  159   207
1990-01-01    48      0    8     63   63      20   42      90  134   182
1980-01-01    44      0    3     27   23      12   17      45   53    97
1970-01-01    42      0    0     13   14       8   10      24   27    69
1960-01-01    41      0    0     10   10       7    8      18   20    61
1950-01-01    41      0    0      7    6       4    5      12   13    54
1940-01-01    36      0    0      3    6       2    3       8    9    45
1930-01-01    34      0    0      0    5       0    0       5    5    39
1920-01-01    32      0    0      0    3       0    0       3    3    35
1910-01-01    30      0    0      0    1       0    0       1    1    31
1900-01-01    28      0    0      0    1       0    0       1    1    29


To be continued...

NASA's Near-Earth Object (NEO) Program coordinates NASA-sponsored efforts to detect, track and characterize potentially hazardous asteroids and comets that could approach the Earth. To learn more, visit the home page of NASA's Near-Earth Object Program: http://neo.jpl.nasa.gov/

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Sunday, April 29, 2012

Near-Earth Objects, Part Five

Spacecraft Missions to Comets and Asteroids

Because comets and asteroids are relatively unchanged leftovers from the solar system formation process, it is important to discern their structures and chemical makeup. These objects formed under the same conditions as did the planets, but unlike the planets, they remained relatively unchanged since their formation. Thus, knowledge of the chemical composition and structure of these objects should offer clues as to the chemical mix and conditions under which the solar system's planets formed 4.6 billion years ago. In addition, information on their compositions and structures will be important should one of them be discovered to be on an Earth threatening trajectory. Knowledge of their compositions and structures will also be important in order to make intelligent choices as to which objects would offer the richest sources of raw materials.

Spacecraft missions are required to understand the detailed chemical compositions and structures of comets and asteroids. There are wide differences between comets and asteroids and even wide differences between different types of asteroids. Some asteroids are likely to be fragile and rich in carbon-based molecules while others are thought to be solid iron. Whether looking for the richest source of raw materials or trying to nudge an Earth threatening object out of harms way, it makes a big difference whether we're dealing with a 50-meter sized fluff ball or a one-mile slab of solid iron. Because comets and asteroids differ so widely in their characteristics, missions have been planned to visit a widely diverse group of objects. After a brief summary of various spacecraft instruments, the seven current missions to comets and asteroids are briefly described.

Typical Spacecraft Instruments: 

Imager: An imager is a television camera system using a charged-coupled device (CCD) detector (the same type of detector in a camcorder).

IR Spectrometer and UV Spectrometer: This infrared (IR) detector measures the light received in several different infrared portions of the light spectrum. In so doing, this instrument can often infer the minerals resident in a neighboring comet or asteroid. The ultraviolet (UV) spectrometer measures a comet's light in several narrow regions of the ultraviolet spectral region in an effort to identify gases that emit radiation in this region of the spectrum.

Lidar: The Lidar instrument sends a pulse of light to the target body and measures the round trip time required for the light signal to travel to and from the bounce point on the target body. By measuring this so-called "light travel time," the distance between the spacecraft and target body can be accurately determined. This instrument is often used to define the shape of the target body and to help navigate the spacecraft when it is in close proximity to the target body.

X-Ray Spectrometer, Gamma Ray Spectrometer, Alpha/X-ray Spectrometer: These spectrometer instruments are all designed to determine the chemical (elemental) composition of the target body's surface materials (what is the chemical makeup of the surface rocks and soils?). When highly energetic radiation or particles fall upon the asteroid's surface materials, each type of atom in these materials responds by emitting radiation in a characteristic frequency. These characteristic frequencies then identify the atoms that are present in the surface soils. X-rays from the sun provide the incident radiation for the x-ray spectrometer. High-speed atomic nuclei (cosmic rays) from space are responsible for inducing the high frequency radiation measured by the gamma ray spectrometer. The alpha particle spectrometer measures the radiation resulting from the bombardment of helium nuclei (alpha particles) upon the asteroid's surface soils; a radioactive source material (e.g., Curium) in the instrument itself provides the source for these alpha particles.

Impact dust mass spectrometer: Once a dust particle hits this detector at high velocity, the resulting charged particles (ions) interact with a magnetic field within the instrument. Measuring the amount their subsequent trajectories are modified by this magnetic field then identifies the specific ions.

Magnetometer: This instrument measures the intrinsic or induced magnetic field of the target body. The charged particle environment in a comet's atmosphere can trap solar magnetic fields and some asteroids, in analogy with the Earth, may have magnetic fields due to their metallic cores.

Plasma Package: A plasma is a cloud of electrically charged atoms or molecules. Plasma instruments are designed to measure the densities and characteristics of plasma clouds that are created when the neutral molecules in cometary atmospheres become charged as a result to the sun's radiation. Plasma instruments will also be used to monitor the plasma (ion) engines used to drive the DS1 spacecraft.


Spacecraft Missions to Comets and Asteroids


Near-Earth Asteroid Rendezvous (NEAR)
Launch: February 17, 1996
Asteroid Mathilde Flyby: June 27, 1997
Asteroid Eros Initial Flyby: December 23, 1998
Asteroid Eros Rendezvous: February 14, 2000

The NEAR mission flew within 1200 km of asteroid Mathilde and spent nearly one year in orbit about asteroid Eros in 2001-2001.

Mission Web site: http://near.jhuapl.edu/


DEEP IMPACT 
Launch: December 30, 2004
Comet Tempel 1 Impact/Flyby: July 4, 2005

Deep Impact mission will impact the surface of comet Tempel 1 thus creating a fresh crater larger than the size of football field and deeper than a seven-story building. The spacecraft will study the crater formation process and examine the subsurface structure of one of the solar system's most primitive objects, a remnant from the outer solar system formation process.

Mission Web site: http://deepimpact.jpl.nasa.gov


DEEP SPACE 1 
Launch: October 25, 1998
Asteroid 9969 Braille Flyby: July 28, 1999
Comet Borrelly Flyby: September 22, 2001

The primary Deep Space 1 mission objectives were to test space technologies. The spacecraft flew within 2000 km of Comet Borrelly on September 22, 2001.

Mission Web site: http://solarsystem.nasa.gov/missions/profile.cfm?MCode=DS1


STARDUST 
Launch: February 6, 1999
Comet Wild-2 Flyby: January 2, 2004
Earth Sample Return: January 15, 2006

The STARDUST spacecraft will image the nucleus of Comet Wild-2, collect dust from both the comet's coma and from interplanetary space and bring these dust samples back to Earth for study.

Mission Web site: http://stardust.jpl.nasa.gov


Hayabusa (MUSES-C) 
Launch: December 2002
Asteroid 25143 Itokawa Rendezvous: September 2005
Earth Sample Return: June 2007

A cooperative mission between Japan and the U.S., the Hayabusa spacecraft rendezvoused with near-Earth asteroid (25143) Itokawa and return asteroid surface samples to Earth for analysis. Itokawa, a 600 meter sized, potato-shaped asteroid, is named after Hideo Itokawa, a Japanese rocket pioneer.

Hayabusa Project (JAXA main site): http://www.isas.ac.jp/e/enterp/missions/hayabusa/index.shtml


ROSETTA 
Launch: March 2, 2004
Comet Churyumov-Gerasimenko Rendezvous: May 2014

After three Earth gravity assists and a Mars gravity assist, the Rosetta spacecraft rendezvoused with, landed upon, the surface of a comet in an effort to study its composition and structure.

Mission Web site: http://sci.esa.int/rosetta


DAWN 
Launch: June 20, 2007
Asteroid Vesta Rendezvous: 2011
Asteroid Ceres Rendezvous: 2015

The Dawn mission will orbit two asteroids on a single voyage. Ceres and Vesta evolved under radically different circumstances in different parts of the solar system more than 4.6 billion years ago. By observing both protoplanets with the same set of instruments, Dawn will provide new insight into the formation and evolution of our solar system.

Mission Web site: http://dawn.jpl.nasa.gov/


To be continued...

NASA's Near-Earth Object (NEO) Program coordinates NASA-sponsored efforts to detect, track and characterize potentially hazardous asteroids and comets that could approach the Earth. To learn more, visit the home page of NASA's Near-Earth Object Program: http://neo.jpl.nasa.gov/

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