ASTEROID IMPACT MISSION AIDA ESANASA COOPERATION 0 088

→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 history • Original AIM mission did not receive sufficient funding at ESA’s ministerial conference in 2016, but large interest from some member states q Lower cost version needed to be defined q Focus on essentials for deflection demonstration AIM D 2 (AIM Deflection Demonstration) was born

AIM-D 2 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 Cube. Sat - Simpler OPS - Launch 2022 or 2023 Direct escape (Soyuz) 1. 5 years cruise 4 months close operations

• AIM D 2 SPACECRAFT First ever investigation of deflection test AIM Framing Camera (AFC) 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 Cube. Sat (COPINS)

AIM Framing Cameras (AFC) • Flight Spares of the DAWN Framing Cameras Ø Spacecraft system, provided by MPI for solar system research Ø Used for Science and navigation • Specifications Ø Ø Field of view: 5. 5 deg. Pixel scale: 93. 7 µrad/pixel Wavelength: 400 -1000 nm 7 filters + clear DAWN FC image of Ceres Didymos spectrum and AFC filter transmission

ASPECT • 3 U Cube. Sat equipped with a spectral imager/spectrometer • Payload: VIS-NIR spectral imager (1 U) • Avionics (1 U) • Propulsion (1 U) • • 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 7 Km is ~3. 5 m

AIM D 2 objectives Measured quantity Mass of Didymoon Measurement Rationale Measure efficiency of impact Dynamic state of Didymoon before and after impact Measure efficiency of impact Density Internal structure => understand impact effect for mitigation (application to other objects Method and Accuracy 10 % mass “Wobble” accuracy ~1 m Orbital period: 0. 1 % Orbit pole: 5 deg. Spin period: 1 % Spin axis: 1 deg. Long-term (days to months) imaging Density: 20 % =>Volume 17 % if mass known to 10 % =>dimensions ~6% Tensile strength, Understanding impact response and Tensile strength from crater size. compressive scaling it to other bodies. Tensile and compressive strength from geomorphology (overhangs, cracks etc. ). Accuracy: order of magnitude Presence of Choice of mining technique, Objects down to a size of ~1 m (10 boulders and interpretation of deflection % of expected crater size), implying grooves, surface experiment image resolution of ~1 m roughness at large scale AFC X X Supporting instrument RSE Lidar (X) ASPECT (X) X X (X)

AIM D 2 objectives Measurement Measured quantity Rationale Method and Accuracy Surface roughness Interpretation of impact experiment, cm-resolution required for direct on cm-scales mining technique measurement. Indirect (rough surface vs. measurement from phase function fine-grained regolith) Homogeneity of Distinguish macroporosity vs. Higher moments of gravity Didymos microporosity potential (up to 3) Spectral properties of unweathered material Ejecta size distribution and velocity Understand original properties of Measurement of crater interior asteroid, needed for impact with ~1 m resolution (10 % of crater interpretation size) 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) AFC Supporting instrument RSE Lidar (X) ASPECT (X) X X (X)

The simplest possible deflection mission: AIM Next q Further reduction of cost by going to asteroid that can be reached with very low Δv q Permits further reduction in cost compared to AIM D 2 q Very small target => Change of heliocentric orbit through DART impact can be easily demonstrated q Prime mission goals can be achieved Disadvantages: Ø No binary target possible (unless one is detected) Ø Deflection demonstration requires change of target for DART § TBD if stand-alone demonstration of gravity tractor is possible

AIM Next target Baseline target: 2001 QJ 142 • Small size (50 -100 m) • Superfast rotator (10 minutes) • Elongated

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 Cube. Sats 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