Asteroid Impact Mission (AIM)

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1 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)

2 NEO mission studies in ESA Near-Earth Objects (NEOs); impact probability is very low but effects can be extremely severe ; 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

3 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

4 AIDA Background The Double Asteroid Redirection Test (DART) study undertaken by APL in 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 4

5 AIDA will send two spacecraft to the binary asteroid Didymos The AIDA concept Asteroid impactor Asteroid rendezvous Each AIDA component is independent and has unique value AIDA = AIM + DART 5/29/2012 5

6 Target: Didymos Didymos Primary rotation Binary orbit period Binary orbit semi-major axis Primary diameter Spectral type Xk 2.26 hr hr 1.05 km 800 m Secondary diameter 150 m Magnitude H 18 Pole Solutions (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 Inclination 3.41 Semi-major axis AU Heliocentric period 2.11 yr Aphelion 2.28 AU Perihelion 1.01 AU 5/29/2012 6

7 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 7

8 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 4 Geology, surface properties Mass key to momentum, size to shape, volume, gravity to internal structure, operations Bulk composition, material mechanical properties, surface thermal inertia Mass from binary orbit, shape model from CAM (or LIDAR), a must, gravity field RSE (not a must?) 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) 5 Density, internal structure Affects absorption of impact energy, data point for study of asteroid mitigation. 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 5/29/2012 8

9 AIM Strawman payload Instrument Mass (kg) Power (W) FOV (deg) Aperture (mm) Dimensions (mm) Notes NAC x 5.3 Micro Laser Altimeter Thermal IR Imager NIR spectrometer x150x50 Combines navigation and science purposes. Measure orbital, rotational state, shape. Heritage: AMIE (SMART-1) x150x50 Precise shape model Low TRL in Europe (BELA, ALADIN). Operational range should be higher than 10 km x40x40 Study of surface temperature and thermal inertia. Heritage: MERTIS (BepiColombo). Mass assumes further miniaturization x50x50 Global mapping of the surface mineralogy. Heritage from SIR (SMART-1) and SIR-2 (Chandrayaan-1). Mass estimate assumes further miniaturization 5/29/2012 9

10 Payload Options AIM p/l Camera TIR Dust Detector Surface system Laser Altimeter Radio Science Experiment 5/29/

11 Interplanetary transfer (EP option) Launch 19/08/2019 Escape velocity [km/s] 1.0 Declination [deg] 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]: /29/

12 AIM Spacecraft Concept 5/29/

13 AIM Mass Budget Propulsion Stage Mass (kg) Structure Clampbands S/C I/F 6.60 S/C adaptor Mechanisms Clamp Band spin table Spring set spin table 3.30 Rendezvous S/C Mass (kg) Dry Mass w.o. margin Dry Mass + 20% margin Propellant Hydrazine 9.00 Propellant Xenon Wet Mass Clamp Band prop module Spring set prop module 3.30 Propulsion SRM Star Dry Mass Propulsion Stage Propellant STAR /29/

14 A Simpler Mission than Don Quijote DQ AIM/DART Comment 2 s/c launched separately 2 s/c developed and launched separately AIM and DART C/D phase independence Impactor launched after Orbiter rdv AIM launched to rdv (in principle) before AIM and DART still fully meaningful in absence of the NEA CoG Δa 100 m DART hits Binary ΔP/P>0.1, no requirement on Δa other spacecraft Measure in-space (CAM) and ground (photometry), Orbiter and RSE required In-situ experiment only at end of mission Autonomous optical navigation 2 days before impact Co-flying, orbiting or RSE not strictly required In-situ as an option, likely after impact Autonomous optical Autonav as an option only. Not mandatory Simple telecom subsystem and operations possible Secondary p/l depends of mass, operations cost, PI contribution Technology experiment for rendezvous spacecraft 5/29/

15 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 Geology, surface properties 5 Density, internal structure 6 Sub-surface properties Mass key to momentum, size to shape, volume, gravity to internal structure, operations Bulk composition, material mechanical properties, surface thermal inertia Affects absorption of impact energy, data point for study of asteroid mitigation. Bulk composition, if significant changes w.r.t surface, post-impact change to thermal inertia 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) 5/29/

16 AIDA Firsts Themes First demonstration of capability to deflect an asteroid and measure the trajectory change First rendezvous with a binary asteroid First visit to an X-type NEO First characterization of hypervelocity impacts on an asteroid First active probes of internal structure and measurements of surface geotechnical properties Comments Both capabilities, to deflect and to measure the deflection, are required to assure that mitigation reduces (and does not increase) an impact hazard Binary systems are an important component of Solar System small body populations and planetary and stellar systems Spectral type X is of unknown composition 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) 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/

17 Summary 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/

18 AIDA mission rationale report Naomi Murdoch (OCA, Coor.) Paul Abell (NASA) Ian Carnelli (ESA) Benoit Carry (ESA) Andy Cheng (JHU/APL) Gerhard Drolshagen (ESA) Moritz Fontaine (ESA) Andrés Gálvez (ESA) Detlef Koschny (ESA) Michael Kueppers (ESA) Patrick Michel (OCA) Cheryl Reed (JHU/APL) Stephan Ulamec (DLR)... Contributions on tests or payload ideas compatible with the mission are very welcome