asteroid hazards gerhard drolshagen, detlef koschny presented in esoc, darmstadt, 05 sep 2013
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
The SSA-NEO Segment, Feb 2013, D. Koschny - Page 4
Asteroid Hazards
Gerhard Drolshagen, Detlef Koschny
Presented in ESOC, Darmstadt, 05 Sep 2013
Imag
e c
red
it:
ES
A
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
Definitions/terminology
500 m
NEO Itokawa(credit: JAXA)
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 4
What is the threat?
Sample case: Chelyabinsk
What is ESA doing?
What is everybody else doing?
“War Game” – a simulated real threat
Conclusions/questions
Outline
Meteorite (10 cm)
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 4
The Tunguska Event
Juni 1908 - 105 years ago
2000 km2 of Taiga were destroyed in Sibiria
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 4
Small impacts are relatively frequent
Crater with 14-m diameter formed by impact from space in 2007 in Carancas, Peru.
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 5
Known number of Near Earth Asteroids
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 6
Near Earth Objects population(From JPL – NEO site)
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 7
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!
Chelyabinsk impact eventVideo from dashboard camera
(from N. Artemieva)
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 9
Chelyabinsk impact eventGround effects
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 10
Chelyabinsk impact eventGround effects
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 11
Chelyabinsk impact event
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 12
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
NEO impacts: frequency and effects
NEO diameter Impact energy [Megatons TNT] (1g TNT ≡ 4184 J)
Typical interval [Years]
Effect
2 mm 1 per hour
(visible for each location)
Nice meteor
3 m 0.002 1 Fireball, Sudan Event, Meteorites reach ground
10 m 0.08 10 Big fireball, fear, shock wave, 5-fold energy of Hiroshima bomb
40 m 5 500 Tunguska explosion or Crater
140 m 220 10,000 Regional destruction, Tsunami
500 m 10,000 200,000 Europe-wide destruction
1 km 80,000 700,000 Millions dead, global effects
10 km 80 million 100 million End of human civilisation
Asteroids (and Comets) hit Earth with very high velocities.
typical: 10 - 20 km/s, 20 times faster than a gun bullet!
ESA’s SSA-NEO System
System overview
Nat
iona
lC
oope
ratin
gte
lesc
opes
SSA tasking centre
SS
A s
enso
rsS
pace
m
issi
ons
Minor Planet Center(US)NEOs
Political entities
General users
NEO image credit: JAXA
National research expertise
- Risk assessment- Obs. Planning- Phys. Properties
SSA-NEO Coord. Centre
- Databases- Light curves- Shape models
Spacemissionstudies
NEO Coordination Centre – ESRIN, Italy
SSA-NEO Coordination Centre - inaugurated 22 May 2013
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 16
The SSA-NEO web portal
Federates some key European assets:
• NEODyS = orbit computation, prediction, risk list
• Physical properties database
• Priority list = showing objects in need of observations
http://neo.ssa.esa.int
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 17
Risk list
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 18
Observations
The SSA-NEO Segment, Feb 2013, D. Koschny - Page 4
2010A2, an asteroid collision observed in February 2002Flyby of asteroid 2012 DA14. Courtesy F. Kugel and J. Caron, Dauban observatory, IAU A77
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 19
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
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 20
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’
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)
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 22
Case study – detection of a threatening object – 06 Sep 2015…
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
Starting 06 Sep 2015
Observations continue (professional and amateur telescopes)
Special observations with infrared telescopes, radar systems (mostly US-based) => allows to constrain physical properties
Arecibo radarPuerto Rico
High-endamateurtelescope
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 24
07 Sep: 13 days before impact
Backg
rou
nd
: C
om
et
Pan
STA
AR
S
C/2
01
1 I
4,
12
Mar
20
13
, D
. K
osch
ny
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
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 25
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…
The SSA-NEO Segment, Feb 2013, D. Koschny - Page 4
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
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 27
20 Sep 2015
The SSA-NEO Segment, Feb 2013, D. Koschny - Page 4
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?
…
SSA-NEO-ESA-HO-0150/1.0 – interface to emergency response, Sep 2013, - Page 29