1. →ASTEROID IMPACT MISSION

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

3. AIM CLOSE PROXIMITY OPERATIONS SCENARIO

4. 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

5. 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

6. 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)

7. 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: deg.
Pixel scale: µrad/pixel
Wavelength: nm
7 filters + clear
DAWN FC image of Ceres

8. 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

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

10. 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

11. 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)

12. 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

13. 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?

14. 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 …

15. 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