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'''WT1190F''' ('''9U01FF6''', '''UDA34A3''', or '''UW8551D''') is a small temporary satellite of the Earth, thought to be [[space junk]],<ref name="space junk">{{cite news |last=Watson |first=Traci |url=http://www.nature.com/news/incoming-space-junk-a-scientific-opportunity-1.18642 |title=Incoming space junk a —scientific opportunity |work=Nature News |date=23 October 2015 |accessdate=2015-10-29 }}</ref> that will impact the Earth on November 13, 2015 at 06:18:34.3 (±1.3 seconds) [[Coordinated Universal Time|UTC]].<ref name="SETI"/> It was first discovered on February 18, 2013 by the [[Catalina Sky Survey]].<ref name="mpmlinfo"/><ref name="Gizmag1023">{{cite news |last=Wood |first=Chris |url=http://www.gizmag.com/esa-rocket-reentry-observations/40021/ |title=ESA to study rare rocket body reentry to improve predictive models |work=Gizmag.com |date=2015-10-23 |accessdate=2015-10-27 }}</ref> It was then lost, and reacquired on November 29, 2013. It was again discovered on October 3, 2015, and the object was soon identified to be the same as the two objects previously sighted by the team, who have been sharing their data through the [[International Astronomical Union]]'s [[Minor Planet Center]] (MPC).<ref name="ESA prediction">{{Cite web|title = Reentry data will help improve prediction models|url = http://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness/Reentry_data_will_help_improve_prediction_models|website = European Space Agency|accessdate = 2015-11-02}}</ref> An early orbit calculation showed that it was orbiting the Earth in an extremely elliptical orbit, taking it from within the [[Geosynchronous orbit|geosynchronous satellite ring]] to nearly twice the distance of the Moon.<ref name="orbitandobs"/> It is also probably the same object as 9U01FF6, another object on a similar orbit discovered on October 26, 2009.
'''WT1190F''' ('''9U01FF6''', '''UDA34A3''', or '''UW8551D''') is a small temporary satellite of the Earth, thought to be [[space junk]],<ref name="space junk">{{cite news |last=Watson |first=Traci |url=http://www.nature.com/news/incoming-space-junk-a-scientific-opportunity-1.18642 |title=Incoming space junk a —scientific opportunity |work=Nature News |date=23 October 2015 |accessdate=2015-10-29 }}</ref> that impacted the Earth on November 13, 2015 at 06:18:34.3 (±1.3 seconds) [[Coordinated Universal Time|UTC]].<ref name="SETI"/> It was first discovered on February 18, 2013 by the [[Catalina Sky Survey]].<ref name="mpmlinfo"/><ref name="Gizmag1023">{{cite news |last=Wood |first=Chris |url=http://www.gizmag.com/esa-rocket-reentry-observations/40021/ |title=ESA to study rare rocket body reentry to improve predictive models |work=Gizmag.com |date=2015-10-23 |accessdate=2015-10-27 }}</ref> It was then lost, and reacquired on November 29, 2013. It was again discovered on October 3, 2015, and the object was soon identified to be the same as the two objects previously sighted by the team, who have been sharing their data through the [[International Astronomical Union]]'s [[Minor Planet Center]] (MPC).<ref name="ESA prediction">{{Cite web|title = Reentry data will help improve prediction models|url = http://www.esa.int/Our_Activities/Operations/Space_Situational_Awareness/Reentry_data_will_help_improve_prediction_models|website = European Space Agency|accessdate = 2015-11-02}}</ref> An early orbit calculation showed that it was orbiting the Earth in an extremely elliptical orbit, taking it from within the [[Geosynchronous orbit|geosynchronous satellite ring]] to nearly twice the distance of the Moon.<ref name="orbitandobs"/> It is also probably the same object as 9U01FF6, another object on a similar orbit discovered on October 26, 2009.


WT1190F has been orbiting the Earth as a temporary satellite since mid 2009 (named as '''UWAIS'''), if not longer. While it has not been positively identified with any known artificial satellites, its estimated density of 0.1 g/cm³ is much lower than would be expected of a natural object. Hence, [[European Space Agency]] astronomers have concluded that the object is likely a fuel tank of some sort.<ref name="mpmlinfo"/><ref name="Gizmag1023"/>
WT1190F has been orbiting the Earth as a temporary satellite since mid 2009 (named as '''UWAIS'''), if not longer. While it has not been positively identified with any known artificial satellites, its estimated density of 0.1 g/cm³ is much lower than would be expected of a natural object. Hence, [[European Space Agency]] astronomers have concluded that the object is likely a fuel tank of some sort.<ref name="mpmlinfo"/><ref name="Gizmag1023"/>

Revision as of 06:19, 13 November 2015

WT1190F
Discovery
Discovered byMount Lemmon Survey (G96),
Mount Lemmon Survey (G96),
Catalina Sky Survey (703)
Discovery date2009/10/26
2013/02/18
2013/11/29
2015/10/03
Designations
Distant artificial satellite (before Jun 2009 to Nov 13, 2015)
Orbital characteristics[1]
Epoch 2015-Oct-03 (JD 2457298.5)
Periapsis21,222 km (13,187 mi) (0.055 LD, 3.33 ER)
Apoapsis655,374 km (407,231 mi) (1.704 LD, 102.75 ER)
338,298 km (210,209 mi) (0.880 LD, 53.04 ER)
Eccentricity0.937269
22.66 days
1.1 km/s @ 0.00226AU
6.191°
Inclination3.197°
311.556°
2015/10/02 14:39:00
314.044°
Satellite ofEarth
Physical characteristics
Dimensions0.7 to 2 meters (2 to 7 ft)
Mass250 to 2,000 kilograms (550 to 4,400 lb)
Mean density
~100 g/m3 (0.006 lb/cu ft)[2]
Albedo>0.1
~16-23
31.3

WT1190F (9U01FF6, UDA34A3, or UW8551D) is a small temporary satellite of the Earth, thought to be space junk,[3] that impacted the Earth on November 13, 2015 at 06:18:34.3 (±1.3 seconds) UTC.[4] It was first discovered on February 18, 2013 by the Catalina Sky Survey.[2][5] It was then lost, and reacquired on November 29, 2013. It was again discovered on October 3, 2015, and the object was soon identified to be the same as the two objects previously sighted by the team, who have been sharing their data through the International Astronomical Union's Minor Planet Center (MPC).[6] An early orbit calculation showed that it was orbiting the Earth in an extremely elliptical orbit, taking it from within the geosynchronous satellite ring to nearly twice the distance of the Moon.[1] It is also probably the same object as 9U01FF6, another object on a similar orbit discovered on October 26, 2009.

WT1190F has been orbiting the Earth as a temporary satellite since mid 2009 (named as UWAIS), if not longer. While it has not been positively identified with any known artificial satellites, its estimated density of 0.1 g/cm³ is much lower than would be expected of a natural object. Hence, European Space Agency astronomers have concluded that the object is likely a fuel tank of some sort.[2][5]

After more observations, astronomers have determined that the object will impact the Earth on November 13, 2015 at 06:18 UTC (11:48 local time),[4] south of Sri Lanka.[2][5] Due to its small size, it is expected that most or all of the object will burn up in the atmosphere before impacting, but will be visible as a bright daytime fireball.[2][5]

Observations

Bright object in the center is WT1190F as observed by the University of Hawaii 2.2-meter telescope.

WT1190F was first discovered by the Mount Lemmon Survey, a participant in the Catalina Sky Survey Near-Earth Object surveying program.[7] The object was identified with an apparent magnitude 19.5 on February 18, 2013, and given the temporary designation UDA34A3, but was lost soon after, with an observation arc of only 5 hours.[8] However, it was again seen by the same survey on November 29, 2013 and given the designation UW8551D and lost again, only being observed for 1 hour 35 minutes.[8]

Most recently, it was recovered on October 3, 2015 and given the designation WT1190F. Its orbit was soon calculated and found to be orbiting the Earth, but not with the orbit of any known artificial satellite. The object's orbit was soon connected, allowing more observations to be made, and several precovery observations have been found of the object, dating back to June 2009.[9]

The type of orbit that WT1190F has is not stable long-term. An object in this type of orbit is likely to impact into Earth or the Moon, or acquire enough orbital speed to be ejected into orbit around the Sun.[10] It is not likely that it has been orbiting Earth for decades.[10] In 2011 the orbit had an eccentricity of 0.33 and perigee (closest approach to Earth) of 248,000 km (154,000 mi).[9] It passed about 22,000 km (14,000 mi) from the Moon on 2012 May 24.[11] By 2013 the eccentricity had increased to 0.70 and the perigee decreased to 105,000 km (65,000 mi).[8]

Orbital Evolution
Epoch Eccentricity Inclination Perigee
(km) 		Apogee
(km)
2011[9] 0.33 59 248383 495045
2013[8] 0.70 78 105639 598686
2015[1] 0.94 3 21221 655374

During WT1190F's orbit, it changes significantly in brightness, from an apparent magnitude 16 at perigee, to magnitude 23 at apogee. It spends most of its time dimmer than magnitude 20.[1] This, combined with solar pressure acceleration, the Yarkovsky effect, and frequent orbital perturbations by the Moon, make it difficult to precisely predict its orbit and location. Before it enters the atmosphere, it might reach magnitude 15 or brighter,[1] roughly the brightness of Pluto. Hours before impact the object had an R magnitude of 15.6.[12][a]

Impact

WT1190F will be make atmospheric entry going 11 kilometers per second (25,000 miles per hour).[13] Whatever is left from the re-entry is expected to fall into the ocean about 100 km off Galle, Sri Lanka.[6] The closest approach to Galle will occur during atmospheric flight when the object has an altitude of 45km and a distance of 51km.[14] For observers in Colombo, Sri Lanka, the object starts out 30 degrees above the horizon coming in from slightly south of due west.[15] Its mass is not sufficient to cause any risk to the area, but the event will still produce a bright fireball. Scientists are implementing observational campaigns to collect as much data as possible on this object to better understand the re-entry of satellites and debris from high orbits.[16][6] The International Astronomical Center (IAC) and the United Arab Emirates Space Agency will utilize a Gulfstream 450 jet to study the re-entry from above the clouds and haze.[16]

Impact Approach[17]
Date vmag Distance
(km) 		Velocity
wrt Earth
(km/s)[18]
05 20.8 602399 0.2
08 20.5 524608 0.5
10 20.0 420800 0.8
11 19.6 345999 1.0
12 19.0 246196 1.4
13 17.1 89914 2.8
Impact ~ -3 0 11.3

Impact has started. (refresh)

Airborne observations

Gulfstream 450 business jet rented for the mission

The International Astronomical Center (IAC) and the United Arab Emirates Space Agency will attempt to observe WT1190F as it falls towards the Earth. The IAC has chartered a Gulfstream 450 jet to bring researchers such as Peter Jenniskens to the area of WT1190F's impact, at a high altitude, to view the event over clouds or haze.[16] The Next TC3 Consortium Asteroid Detection and Early Warning team has narrowed the atmospheric entry time to ±1.3 seconds.[4]

See also

Previous impacts by known objects

Previous temporary satellites

Notes

  1. ^ Even near apparent magnitude ~15.6 it will be about 7000 times too faint to be seen by the naked eye. Math:

References

  1. ^ a b c d e Gray, Bill. "Pseudo-MPC for UDA34A3 = UW8551D = WT1190F". Project Pluto. Retrieved 23 October 2015.
  2. ^ a b c d e "WT1190F comes back: ESA NEOCC watching rare reentry". Minor Planet Mailing List. Retrieved 24 October 2015.
  3. ^ Watson, Traci (23 October 2015). "Incoming space junk a —scientific opportunity". Nature News. Retrieved 2015-10-29.
  4. ^ a b c "Rapid Response to the next TC3 Consortium". SETI Institute. Retrieved 2015-11-10.
  5. ^ a b c d Wood, Chris (2015-10-23). "ESA to study rare rocket body reentry to improve predictive models". Gizmag.com. Retrieved 2015-10-27.
  6. ^ a b c "Reentry data will help improve prediction models". European Space Agency. Retrieved 2015-11-02.
  7. ^ "Catalina Sky Surveys". NASA. 2013-03-05. Retrieved 2015-10-27.
  8. ^ a b c d ""Pseudo-MPEC" for UDA34A3 = UW8551D". Project Pluto. Retrieved 27 October 2015.
  9. ^ a b c Gray, Bill (30 October 2015). "Pseudo-MPEC for UDA34A3 = UW8551D = WT1190F". Project Pluto. Retrieved 8 November 2015.
  10. ^ a b WT1190F FAQs – Bill Gray
  11. ^ Gray, Bill (5 November 2015). "Pseudo-MPEC for UDA34A3 = UW8551D = WT1190F". Project Pluto. Retrieved 8 November 2015.
  12. ^ "DASO Circular No. 536". Minor Planet Center. 13 November 2015.
  13. ^ "ESA SPONSORS WT1190F OBSERVATIONS". esa blog. 30 October 2015. Retrieved 2015-11-10.
  14. ^ Gray, Bill (11 November 2015). "Ephemerides for (Gal) Galle, Sri Lanka". Project Pluto. Retrieved 12 November 2015.
  15. ^ Gray, Bill (13 November 2015). "Ephemerides for (Col) Colombo, Sri Lanka". Project Pluto. Retrieved 12 November 2015.
  16. ^ a b c Al-Ashi, Sameh (4 November 2015). "UAE sponsors airborne campaign to observe November 13 entry of space debris WT1190F". IAC. Retrieved 8 November 2015.
  17. ^ The Distant Artificial Satellites Observation Page
  18. ^ Ephemeris (VmagOb value "Table setting #22")
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