→ASTEROID IMPACT MISSION

AIDA: ESA-NASA COOPERATION 0.088 AU → opportunity: Didymos close approach with Earth in October 2022. Asteroid, target and impact date fixed

AIM CLOSE PROXIMITY OPERATIONS SCENARIO

AIM D2 (AIM Deflection Demonstration) was born AIM history Original AIM mission did not receive sufficient funding at ESA’s ministerial conference in 2016, but large interest from some member states Lower cost version needed to be defined Focus on essentials for deflection demonstration AIM D2 (AIM Deflection Demonstration) was born

AIM-D2 MISSION SCENARIO Simplification of the mission scenario meeting main mission objectives: full characterisation of DART impact and measurement of Didymos deflection Changes: No Optical comm No lander One CubeSat Simpler OPS Launch 2022 or 2023 Direct escape (Soyuz) 1.5 years cruise 4 months close operations

AIM D2 SPACECRAFT First ever investigation of deflection test AIM Framing Camera (AFC) First ever investigation of deflection test Detailed analysis of impact crater First deep-space cubesat First binary asteroid and smallest ever asteroid visited Payload: - Aim Framing Cameras (in storage) - ASPECT cubesat (under consolidation, FIN) - LIDAR (Consortium led by EFACEC, Portugal) - Radio Science Experiment CubeSat (COPINS)

AIM Framing Cameras (AFC) Didymos spectrum and AFC filter transmission Flight Spares of the DAWN Framing Cameras Spacecraft system, provided by MPI for solar system research Used for Science and navigation Specifications Field of view: 5.5 deg. Pixel scale: 93.7 µrad/pixel Wavelength: 400-1000 nm 7 filters + clear DAWN FC image of Ceres

ASPECT 3U CubeSat equipped with a spectral imager/spectrometer Payload: VIS-NIR spectral imager (1U) Avionics (1U) Propulsion (1U) Semi-autonomous operations Onboard payload data processing Aalto-1 and Aalto-2 heritage (earth observation) Better than 2 m spatial resolution (pixel size) from 4 km orbit Imaging of Didymoon prior and after DART impact Didymos will also be imaged

Lidar Lidar originally designed for lander missions Sampling frequency 20 Hz Range ~7 km Footprint at 7Km is ~3.5m

Supporting instrument AIM D2 objectives Measurement Supporting instrument Measured quantity Rationale Method and Accuracy AFC RSE Lidar ASPECT Mass of Didymoon Measure efficiency of impact 10 % mass “Wobble” accuracy ~1m X (X) Dynamic state of Didymoon before and after impact Orbital period: 0.1 % Orbit pole: 5 deg. Spin period: 1 % Spin axis: 1 deg. Long-term (days to months) imaging   Density Internal structure => understand impact effect for mitigation (application to other objects Density: 20 % =>Volume 17 % if mass known to 10 % =>dimensions ~6% Tensile strength, compressive strength Understanding impact response and scaling it to other bodies. Tensile strength from crater size. Tensile and compressive strength from geomorphology (overhangs, cracks etc.). Accuracy: order of magnitude Presence of boulders and grooves, surface roughness at large scale Choice of mining technique, interpretation of deflection experiment Objects down to a size of ~1m (10 % of expected crater size), implying image resolution of ~1m

Supporting instrument AIM D2 objectives Measurement Supporting instrument Measured quantity Rationale Method and Accuracy AFC RSE Lidar ASPECT Surface roughness on cm-scales (rough surface vs. fine-grained regolith) Interpretation of impact experiment, mining technique cm-resolution required for direct measurement. Indirect measurement from phase function (X)   Homogeneity of Didymos Distinguish macroporosity vs. microporosity Higher moments of gravity potential (up to 3) X Spectral properties of unweathered material Understand original properties of asteroid, needed for impact interpretation Measurement of crater interior with ~1m resolution (10 % of crater size) Ejecta size distribution and velocity Understand impact response Measurement of impact with a cadence of 5 sec. (TBC) Long term measurements at low cadence (Size distribution from effect of radiation pressure)

The simplest possible deflection mission: AIM Next Further reduction of cost by going to asteroid that can be reached with very low Δv Permits further reduction in cost compared to AIM D2 Very small target => Change of heliocentric orbit through DART impact can be easily demonstrated Prime mission goals can be achieved Disadvantages: No binary target possible (unless one is detected) Deflection demonstration requires change of target for DART TBD if stand-alone demonstration of gravity tractor is possible

Baseline target: 2001 QJ 142 AIM Next target Small size (50-100 m) Superfast rotator (10 minutes) Elongated Does it look like other asteroids effected by YORP?

AIM in the context of future planetary missions Plato 2018 2020 AIM is the only opportunity of an ESA small body mission ( ) in the next 20 years and would be the first ESA mission to a small body since the 2004 launch of Rosetta The interest (media, public, community) is still at the highest level Some ESA member states are still willing to make it happen, and efforts are currently under way to do so. Stay tuned …

CONCLUSIONS Simplified (rendezvous) AIM options achieve full asteroid mitigation objectives (detailed discussion by Michel et al. Adv. Space Res. in preparation). Deep-space CubeSats technology demonstration compatible with reduced cost and schedule scenarios, provide mission risk reduction during impact observations and additional information relevant to resources characterization. Launch delayed to 2022 or 2023 Mission with further reduced cost is possible, but requires change of target

www.esa.int/aim