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Asteroid Hazards Gerhard Drolshagen, Detlef Koschny Presented in ESOC, Darmstadt, 05 Sep 2013

Asteroid Hazards Gerhard Drolshagen, Detlef Koschny Presented in ESOC, Darmstadt, 05 Sep 2013. Image credit: ESA. Definitions/t erminology. Near-Earth Object (NEO): Any asteroid coming closer than 0.3 AU to the Earth 1 AU = Astronomical Unit = distance Sun-Earth = 149.6 Mio km

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Asteroid Hazards Gerhard Drolshagen, Detlef Koschny Presented in ESOC, Darmstadt, 05 Sep 2013

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  1. Asteroid Hazards Gerhard Drolshagen, Detlef Koschny Presented in ESOC, Darmstadt, 05 Sep 2013 Image credit: ESA

  2. Definitions/terminology • Near-Earth Object (NEO): Any asteroid coming closer than 0.3 AU to the Earth • 1 AU = Astronomical Unit = distance Sun-Earth = 149.6 Mio km • Threatening object: Any asteroid that may hit the Earth • Risk list: A list containing all threatening objects NEO Itokawa(credit: JAXA) 500 m

  3. Outline • What is the threat? • Sample case: Chelyabinsk • What is ESA doing? • What is everybody else doing? • “War Game” – a simulated real threat • Conclusions/questions Meteorite (10 cm) SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 4

  4. The Tunguska Event Juni 1908 - 105 years ago 2000 km2 of Taiga were destroyed in Sibiria

  5. Small impacts are relatively frequent Crater with 14-m diameter formed by impact from space in 2007 in Carancas, Peru.

  6. Known number of Near Earth Asteroids

  7. Near Earth Objects population (From JPL – NEO site)

  8. Estimated Number of Asteroids and NEOs(Data from NEODyS or JPL NEO site, Aug 2013) • > 600 000 known Asteroids • > 10 000 known NEOs • > 400 NEOs in risk list (NEOs with small but non-zero impact probability within next 100 years) • Estimated number of known NEOs: • 90% of NEOs with diameter larger than 1 km (≥ 860 NEAs + 94 near-Earth Comets of a total of ≈ 1050) • 15-25% of NEOs larger than 140 m (total ≈ 20,000 - 30,000) • < 2.0% of NEOs larger than 30 m (total ≈ 500,000 - 1,000,000) Most NEOs are still unknown!

  9. Chelyabinsk impact eventVideo from dashboard camera (from N. Artemieva)

  10. Chelyabinsk impact eventGround effects

  11. Chelyabinsk impact eventGround effects

  12. Chelyabinsk impact event Location: 55.2o N, 61.4o E (near Chelyabinsk, Russia) Date/time: 15 Feb 2013, 03:20 UT (09:20 LT) Diameter of object: 19 m, mass ≈ 12000 t Entry velocity: 18.6 km/s, entry angle: 20o from surface Total energy: equiv. to 480 kt TNT Altitude of main explosion: 30 – 25 km Max brightness of fireball: m ≈ -30 (about 30 x sun brightness) 7300 buildings damaged > 1500 people injured > 100 kg of meteorites found (usually small pieces, asteroid was ordinary chondrite) Asteroid could not be seen approaching (too close to sun direct.) and was too faint for prior detection during the last 10 years

  13. NEO impacts: frequency and effects • Asteroids (and Comets) hit Earth with very high velocities. • typical: 10 - 20 km/s, 20 times faster than a gun bullet!

  14. ESA’s SSA-NEO System

  15. SSA tasking centre Spacemissionstudies Political entities SSA-NEO Coord. Centre SSA sensors • - Risk assessment • Obs. Planning • Phys. Properties - Databases - Light curves - Shape models Space missions National research expertise General users System overview Minor Planet Center(US) NEOs NationalCooperatingtelescopes NEO image credit: JAXA

  16. NEO Coordination Centre – ESRIN, Italy SSA-NEO Coordination Centre - inaugurated 22 May 2013

  17. The SSA-NEO web portal http://neo.ssa.esa.int • Federates some key European assets: • NEODyS = orbit computation, prediction, risk list • Physical properties database • Priority list = showing objects in need of observations

  18. Risk list

  19. Observations Flyby of asteroid 2012 DA14. Courtesy F. Kugel and J. Caron, Dauban observatory, IAU A77 2010A2, an asteroid collision observed in February 2002 SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 19

  20. Discussions within UN COPUOS • Action Team 14 of the United Nations Committee on the Peaceful Uses of Outer Space (UN COPUOS) has developed a response strategy • Adopted in Jun 2013 by COPUOS • Two groups are to be installed: • International Asteroid Warning Network (includes interface to emergency response) • Space Missions Planning Advisory Group

  21. Case study – detection of a threatening object – 05 Sep 2015… • ESA SSA-NEO survey telescope discovers moving object close to the celestial equator • Position measurements are sent to Minor Planet Center (MPC) in US as part of regular observation process • MPC checks orbit; object is potential NEO. Posted on ‘NEO Confirmation Page’

  22. Case study – detection of a threatening object – 06 Sep 2015… • Other observers perform ‘follow-up’ observations • Object is confirmed after 24 hours – receives a ‘designation’ • NEODyS computes detailed orbit – finds an impact solution. Impact risk: 1/10 => SSA-NEO managers are informed • Based on visual brightness: size estimate 20 m +/- 10 m => could generate ground effects • JPL Sentry impact monitoring system confirms • SSA Programme Manager is informed • news release is sent to an email distribution list (triggered at impact probability of >1/100). • Notification to special distribution list (including civil protection specialists)

  23. 06 Sep: 14 days before impact • Velocity: 18.7 km/s • Size: 20 m +/- 10 m • Density: 1 g/cm3 .. 8 g/cm3 • Impact probability: 1/10 • Time of impact: 20 Sep 2015, 20:10 +/- 3 min • Kinetic energy: • min: 21.9 Kt • max: 4.87 Mt

  24. Starting 06 Sep 2015 High-endamateurtelescope • Observations continue (professional and amateur telescopes) • Special observations with infrared telescopes, radar systems (mostly US-based) => allows to constrain physical properties Arecibo radarPuerto Rico

  25. 07 Sep: 13 days before impact • Velocity: 18.7 km/s • Size: 20 m +/- 10 m • Density: 1 g/cm3 .. 8 g/cm3 • Impact probability: 1 • Time of impact: 20 Sep 2015, 20:10 +/- 1 min • Kinetic energy: • min: 21.9 Kt • max: 4.87 Mt Background: Comet PanSTAARS C/2011 I4, 12 Mar 2013, D. Koschny

  26. Possible press response • Reports on Alien invasions • Claim that Space Agencies are hiding information • Killer-asteroid on the way! • Deadly asteroid will destroy Berlin/New York /Tokyo /Moscow/Sidney/Bejing…

  27. 13 Sep: 7 days before impact • Velocity: 18.7 km/s • Size: 20 m +/- 3 m • Density: 1 g/cm3 .. 3.8 g/cm3 • Impact probability: 1 • Time of impact: 20 Sep 2015, 20:10 +/- 10 sec • Kinetic energy: • min: 110.6 Kt • max: 1.04 Mt

  28. 20 Sep 2015

  29. Questions to the audience… • Who should be informed? • At which point in time would you expect to be informed? And at which impact probability? Only when 1? • Which information would you need? • Recommended measures? • …

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