Asteroid Impact Mission (AIM)

Asteroid Impact Mission (AIM)
Andrés Gálvez, ESA HQ, Paris, France
Ian Carnelli, ESA HQ, Paris, France
Carlos Corral, ESTEC, Noordwijk, The Netherlands
& the AIDA team (JHU/APL, NASA, OCA. DLR)
NEO mission studies in ESA
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Near-Earth Objects (NEOs); impact probability is very low but effects
can be extremely severe ;
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ESA addresses risk assessment and works with data users,
but these users also need missions
There is still very limited practical knowledge on the best
technology approach to tackle NEO impact threats.
NASA/JHU
ESA Don Quijote study
 After ESA’s Mission
Advisory Panel
recommendation, ESA
studied Don Quijote
asteroid mission
 Two launches
 Interceptor
 Rendezvous
 Not affordable techno
demonstration for ESA
5/29/2012
3
AIDA Background
 The Double Asteroid Redirection Test (DART)
study undertaken by APL in 2011-2012 with
participation of NASA
 NASA HQ, GSFC, JSC, LaRC, JPL
 Asteroid impact and deflection,
 The Asteroid Impact Mission (AIM) study
undertaken by ESA in 2012 with OCA, DLR
 Impact test and characterization
5/29/2012
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The AIDA concept
 AIDA will send two spacecraft to the
binary asteroid 65803 Didymos
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Asteroid impactor
Asteroid rendezvous
 Each AIDA component is independent
and has unique value
AIDA = AIM + DART
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5
Target: Didymos
5/29/2012
Didymos
Spectral type Xk
Primary rotation
2.26 hr
Binary orbit period
Binary orbit semi-major axis
Primary diameter
Secondary diameter
Magnitude H
Pole Solutions
11.91 hr
1.05 km
800 m
150 m
18
(λ,β) = (157°,19°); (329°,-70°)

Spacecraft impact (in
2022) will change
mutual orbit of binary

Period change is
measurable from
Earth by shift in
mutual event timing
Heliocentric Orbit
Eccentricity
0.384
Inclination
3.41°
Semi-major axis
1.645 AU
Heliocentric period
2.11 yr
Aphelion
2.28 AU
Perihelion
1.01 AU
6
Key Objectives
AIM as a monitoring mission
 target characterization through a rendezvous
and observation from a distance
 characterization also from ground (radar,
optical) – simpler, more robust mission
 autonavigation demonstration
 cost target under 150M€
Distance: 5-17 km (100 km for
DART impact)
Characterization
point
NAC, thermal IR, NIR spectrom.
to Sun
5/29/2012
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AIM Payload Objectives
P# Parameter
Relevance to goal
Possible measurement / is it a must have?
1
•
Orbital state
•
Key to determine momentum
•
Ground (photometry, radar), in-space (CAM) – a must
2
•
Rotation
state
•
Key to determine momentum
•
Ground (photometry, radar), in-space (CAM) – a must
3
•
Size, Mass,
Gravity
•
Mass key to momentum, size to shape,
volume, gravity to internal structure,
operations
•
Mass from binary orbit, shape model from CAM (or
LIDAR), a must, gravity field RSE (not a must?)
4
•
Geology,
surface
properties
•
Bulk composition, material mechanical
properties, surface thermal inertia
•
VIS photometry to derive spectral type (must), IR
spectrometer mineralogy (not a must)
TIR for Yarkowski / YORP (not a must if not large source
of error)
Density,
internal
structure
•
•
Affects absorption of impact energy,
“data point” for study of asteroid
mitigation.
•
•
5
•
5/29/2012
•
Bulk values derived from mass, shape model
Radar Tomography, seismic probing. l largely increases
complexity and not a must (conclusion Don
Quijote/NEO1). = outside scope AIM
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AIM Strawman payload
Instrument
Mass
(kg)
Power
(W)
FOV
(deg)
Aperture
(mm)
Dimensions
(mm)
Notes
NAC
2.0
0.75
5.3 x
5.3
14.2
200x150x50
Combines navigation and science
purposes. Measure orbital, rotational
state, shape.
Heritage: AMIE (SMART-1).
Micro Laser
Altimeter
2.5
4
0.003
30
200x150x50
Precise shape model
Low TRL in Europe (BELA, ALADIN).
Operational range should be higher
than 10 km.
Thermal IR
Imager
1.5
1
4
40
60x40x40
Study of surface temperature and
thermal inertia.
Heritage: MERTIS (BepiColombo).
Mass assumes further
miniaturization.
NIR
spectrometer
1.5
7
4
38
100x50x50
Global mapping of the surface
mineralogy. Heritage from SIR
(SMART-1) and SIR-2
(Chandrayaan-1). Mass estimate
assumes further miniaturization
5/29/2012
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Payload Options
AIM
Camera
p/l
Dust
Detector
TIR
Laser Altimeter
Surface
system
Radio
Science
Experiment
5/29/2012
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Interplanetary transfer (EP option)
Launch
19/08/2019
Escape velocity [km/s]
1.0
Declination [deg]
-14.46
Escape mass [kg]
400
Earth swing-by
07/11/2020
Infinite velocity at SB [km/s]
5.44
Vel. at pericentre [km/s]
10.8
Pericentre altitude [km]
2854
Arrival
01/08/2022
Final mass [kg]
324
SEP delta-v [km/s]
2.9
Xenon consumption [kg]:
73
Hydrazine consumption [kg]:
5
Thruster on time [d]:
213
Total Impulse[10^6kg m/s]:
1.05
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AIM Spacecraft Concept
5/29/2012
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AIM Mass Budget
Propulsion Stage Mass (kg)
Rendezvous S/C Mass (kg)
Structure
Dry Mass w.o. margin
269.60
Dry Mass + 20% margin
323.52
23.21
Clampbands S/C I/F
S/C adaptor
6.60
16.61
Mechanisms
35.20
Clamp Band spin table
Spring set spin table
Clamp Band prop module
Spring set prop module
14.30
3.30
SRM Star 48
137.55
5/29/2012
Wet Mass
9.00
73.00
405.52
3.30
137.55
Propellant STAR 48
Propellant Xenon
14.30
Propulsion
Dry Mass Propulsion
Stage
Propellant Hydrazine
195.96
1222.00
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A Simpler Mission than Don Quijote
DQ
2 s/c launched
separately
Impactor launched
after Orbiter rdv
NEA CoG Δa ≥ 100 m
Orbiter and RSE
required
AIM/DART
2 s/c developed and
launched separately
AIM launched to rdv
(in principle) before
DART hits
Binary ΔP/P>0.1, no
requirement on Δa
Comment
AIM and DART C/D phase
independence
AIM and DART still fully
meaningful in absence of the
other spacecraft
Measure in-space (CAM) and
ground (photometry),
Co-flying, orbiting or
RSE not strictly
required
Simple telecom subsystem
and operations possible
In-situ experiment
In-situ as an option,
only at end of mission likely after impact
Secondary p/l depends of
mass, operations cost, PI
contribution
Autonomous optical
navigation
2 days before impact
Technology experiment for
rendezvous spacecraft
Autonomous optical
Autonav as an option
only. Not mandatory
5/29/2012
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Impact Test and Characterisation
P# Parameter
Relevance to goal
AIDA measurement
1
Orbital state
Key to determine momentum
Ground (photometry, radar), in-space (CAM/ LIDAR)
2
Rotation state
Key to determine momentum
Ground (photometry, radar), in-space (CAM)
3
Size, Mass,
Gravity
4
Mass key to momentum, size to shape,
volume, gravity to internal structure,
operations
Geology, surface Bulk composition, material mechanical
properties
properties, surface thermal inertia
5
Density, internal Affects absorption of impact energy,
structure
“data point” for study of asteroid
mitigation.
6
Sub-surface
properties
Bulk composition, if significant changes
w.r.t surface, post-impact change to
thermal inertia
5/29/2012
Mass from binary orbit, shape model from CAM
(+LIDAR), gravity field RSE (option)
•
•
AIM+DART images
VIS photometry to derive spectral type, IR
spectrometer mineralogy
• TIR for Yarkovski / YORP,
• surface payload (option)
Bulk value derived from mass, shape model
Crater interior (CAM, IR)
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AIDA Firsts
Themes
Comments
First demonstration of
capability to deflect an
asteroid and measure the
trajectory change
Both capabilities, to deflect and to measure the
deflection, are required to assure that mitigation
reduces (and does not increase) an impact hazard
First rendezvous with a binary
asteroid
Binary systems are an important component of Solar
System small body populations and planetary and
stellar systems
First visit to an X-type NEO
Spectral type X is of unknown composition
First characterization of
hypervelocity impacts on an
asteroid
Most asteroids, and NEAs in close binaries, are
believed to be rubble piles, but we don’t know how
they would respond to large scale impacts (needed
information to understand asteroid collisional
evolution and size distributions, as well as asteroid
deflection for hazard mitigation)
First active probes of internal
structure and measurements
of surface geotechnical
properties
Although Didymos is not necessarily a human
exploration target, these measurements expand our
knowledge base of asteroid surfaces and help prepare
for human exploration
5/29/2012
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Summary
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ESA, OCA, DLR studied AIM, a simple binary
asteroid rendezvous inspired on “Don Quijote”
Ongoing work on JHU/APL’s DART to complement
AIM for a joint mission to Didymos, eclipsing binary
AIM+ DART = AIDA (Asteroid Impact Deflection
Assessment), an affordable, risk free cooperation
AIDA is a good opportunity to study hypervelocity
impacts, ejecta and crater formation and to deepen
our knowledge on how impact affects dynamics of
objects in space
Call for payload ideas coming soon
5/29/2012
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AIDA mission rationale report
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Naomi Murdoch (OCA, Coor.)
Paul Abell (NASA)
Ian Carnelli (ESA)
Benoit Carry (ESA)
Andy Cheng (JHU/APL)
Gerhard Drolshagen (ESA)
Moritz Fontaine (ESA)
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Andrés Gálvez (ESA)
Detlef Koschny (ESA)
Michael Kueppers (ESA)
Patrick Michel (OCA)
Cheryl Reed (JHU/APL)
Stephan Ulamec (DLR)
...
http://www.esa.int/neo
Contributions on tests or payload ideas compatible with the
mission are very welcome