A liter-sized CubeSat. Photo courtesy 
of Cal Poly CubeSat Program.

Basic CubeSats are 10cm on the side and a liter in volume, and have been developed by and for student space programs worldwide, beginning at Cal Poly and Stanford in California more than two decades ago. Now this increasingly capable toolkit is being pushed beyond low Earth orbit. The 1st Interplanetary CubeSat Workshop will be held in late May in Cambridge, Massachusetts, and NASA/JPL will have related presentations at the annual CubeSat Developer's Workshop at Cal Poly this month, including "Applications ... to Small-Body Exploration." Photo courtesy of Cal Poly CubeSat Program.

Contents  on 4 April '12

Asteroid/Comet Connection (A/CC) Resources:

The latest A/CC news is available via framed access, RSS news feed RSS news feed, or redirection. - Note: A/CC has a main Web site and also a backup site with its own duplicate RSS news feed.

Navigation tips: Use the << and >> arrows on the menus for each regular section (Observers, Risks, etc.) to move to the previous and next day's news for that section. Use the Index menu item to access specific days through a calendar interface. And use the all-up news archive to access news from any time since A/CC began in early 2002. To keep track of what's new each day, watch the Chronology section.

Traffic Report  on 4 April '12

Seven objects reported inside ten LD

Seven visitors are reported moving inside ten lunar distances (LD) of our planet today. Within Earth's Hill sphere, risk-listed 2012 FA57 comes its closest to Earth on this passage, reaching 1.15 LD at 2144 UTC, and its closest to the Moon -- 1.56 LD at 0938 UTC, while 2012 FH58 exits the sphere, flying from 3.64 to 4.37 LD.

Out further, radar target intruder 2012 EG5 is headed away from 4.94 to 6.81 LD, and intruder 2012 FS35 from 6.47 to 7.24 LD. Three objects depart from within ten LD: 2012 FQ62 moving from 8.09 to 12.13 LD, 2012 FV23 from 9.30 to 10.33 LD, and 2012 FS52 from 9.84 to 11.94 LD.

Coming towards us next, risk-listed 2012 GD arrives inside ten LD on April 8th and returning 2007 HV4 on April 14th.

This report was posted at 1537 UTC with follow-up in today's DOU MPEC for 2012 GE, 2012 GD, and 2012 EG5.

Notes: Ten times the distance to the Moon (ten LD) has no astronomical significance but is a useful reporting boundary. Earth's Hill sphere (of gravitational influence) is estimated to extend out to around 3.89 LD. Object distances are interpreted by A/CC from JPL Horizons data. See also current sky chart and object details (alt-details), ephemerides, and today's timeline.

NEOCP Activity  on 4 April '12

The MPC's NEO Confirmation Page has 25 listings

When last checked at 2359 UTC today, the Minor Planet Center's Near Earth Object discovery Confirmation Page (NEOCP) had 25 objects listed. Of these, five were "one nighters." So far The Tracking News has counted a total of 26 listings on the NEOCP today.

To learn how observers use the NEOCP, see the Practical guide on how to observe NEOCP object at Suno Observatory by Birtwhistle et al.

New MPECs  on 4 April '12

Minor Planet Electronic Circulars

As of last check at 2359 UTC, there have been two MPECs posted today from the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts.

MPEC 2012-G21 - "16:13 UT" - 2012 GK

<< DOU on 4 Apr. '12 >>  MPEC 2012-G20 - "06:03 UT" - Daily Orbit Update

Observers  on 4 April '12

Fourteen observers appear in today's MPECs.

CodeObserver / observatory
H21Astronomical Research Obs. Westfield in Illinois, 11 in MPEC 2012-G20 -- 2012 FZ23, 2012 FT62, 2012 FR62, 2012 FP62, 2012 FJ, 2012 FG58, 2012 EM8, 2012 DX75, 2011 QD48, 2004 VB, 186823
G51Byrne Obs. in southern California, 1 in MPEC 2012-G21 -- 2012 GK
807|Robert Holmes in Illinois via Cerro Tololo Inter-American Obs. (CTIO) in Chile, 9 in MPEC 2012-G20 -- 2012 GE, 2012 FR62, 2012 FQ52, 2012 FO62, 2012 FG58, 2012 BK11, 2012 BJ11, 2011 WO4, 2010 RJ42
F65%Tim Lister in southern California via Faulkes Telescope North in Hawaii, 1 in MPEC 2012-G21 -- 2012 GK
F655David Asher in Northern Ireland via Faulkes Telescope North in Hawaii, 1 in MPEC 2012-G20 -- 2012 FG58
E100Tim Lister in southern California via Faulkes Telescope South in New South Wales, 1 in MPEC 2012-G20 -- 2012 EG5
H15ISON-NM Obs. in New Mexico, 1 in MPEC 2012-G20 -- 2012 FZ23
C94MASTER-II Obs. Tunka in Russia, 1 in MPEC 2012-G20 -- 6455
H01Magdalena Ridge Obs. in New Mexico, 1 in MPEC 2012-G20 -- 101955
583Odessa-Mayaki Obs. in the Ukraine, 1 in MPEC 2012-G20 -- 2012 EG5
F51Pan-STARRS 1 (PS1) in Hawaii, 2 in MPECs 2012-G20 & 2012-G21 -- 2012 GK, 2012 FM52
H23Pear Tree Obs. in Florida, 2 in MPEC 2012-G20 -- 2012 DX75, 2012 DO
D90`Kevin Hills in England via RAS Obs. Moorook in South Australia, 4 in MPEC 2012-G20 -- 2012 FY23, 2012 FD23, 2012 DX75, 2012 DO
291Spacewatch 1.8m telescope in Arizona, 4 in MPECs 2012-G20 & 2012-G21 -- 2012 GK, 2012 GD, 2012 FO62, 2012 FM52
H47Vicksburg Obs. in Mississippi, 2 in MPEC 2012-G20 -- 2006 VY13, 189008
For a list of all participating observatories that have Web addresses, see A/CC's Observatory Links page.

Impact Risk Monitoring  on 4 April '12

Summary Risk Table for Risk Assessments Updated Today   (last checks: NEODyS and JPL at 2359 UTC)
See the CRT page for a list of all objects rated recently as risks and our ephemerides page for a list of risk-listed objects under current observation.
The time horizon for JPL is 100 years from today and for NEODyS is usually the year 2090. Both also post impact solutions beyond 100 years for a few special objects.
For the latest official risk assessments, and for explanations of the terminology, see the JPL NEO Program Sentry and NEODyS CLOMON2 risk pages.





Notes for Today's Latest Risk Assessments
2012 GKJPL Sentry18392019-21111952.3e-06-4.39-4.880JPL: "Analysis based on 12 observations spanning 2.1458 days (2012-Apr-02.35905 to 2012-Apr-04.504816)." Diameter approximately 0.097 km. from mean, weighted H=22.7.
2012 GDJPL Sentry15352049-210337.5e-09-9.03-9.040JPL: "Analysis based on 14 observations spanning 2.0829 days (2012-Apr-01.34437 to 2012-Apr-03.4273)." Diameter approximately 0.014 km. from mean, weighted H=26.9.
2012 FM52JPL Sentry1535R E M O V E DJPL: Risk listing removed at 0849 UTC.

Legend: VI# = VI count, Prob Cum = cumulative probability, PS Cum/Max = cumulative/maximum Palermo Scale, TS = Torino Scale

An impact solution, also known as a "virtual impactor" (VI), is not a prediction but rather a possibility derived from a variant orbit calculation that cannot be eliminated yet based on the existing data. Elimination can come quickly with just a little further observation or may take weeks or months, sometimes years. Once superceded or eliminated, a former impact solution has zero relevance to an object's risk. See Jon Giorgini's "Understanding Risk Pages" to learn more.

Chronology  on 4 April '12

Times are UTC for when items were noted or added by The Tracking News.

1839Noted that JPL Sentry has posted 2012 GK as an impact risk - see above
1648Grabbed MPEC 2012-G21 - 2012 GK - see above
1537Posted Traffic Report
1535Noted that JPL Sentry has removed 2012 FM52 as an impact risk - see above
Noted that JPL Sentry has updated its 2012 GD risk assessment - see above
Grabbed MPEC 2012-G20 - Daily Orbit Update - see above