2019.A.3.5. ESA F-Class mission candidate AI3: A mothership/daughters concept to deliver CubeSats to an asteroid


Patrick Bambach (1)
Jakob Deller (1)
Esa Vilenius (1)
Ozgur Karatekin (2)
Francisco da Silva Pais Cabral (3)
Sampsa Pursiainen (4)
Liisa-Ida Sorsa (4)
Koji Wada (5)
Tomas Kohout (6)
Liisa-Ida Sorsa (4)
Hannah Goldberg (7)
Paolo Tortora (80

  1. Max Planck Institute for Solar System Research, Germany
  2. Royal Observatory of Belgium
  3. GMV, Spain
  4. Tampere University, Finland
  5. Chiba Institute of Technology, Japan
  6. University of Helsinki, Finland
  7. Gomspace, Denmark
  8. University of Bologna, Italy




CubeSats, Asteroids, ESA


For the ESA F-Class mission call we have submitted the AI3 proposal, which is currently in the second and final selection round. The mission is based on a mothership with four 16U deployers, which provides a max dv of 4.5km/s. After arrival the mothership will serve as communication relay for the CubeSats. For the AI3 mission two 16U deployers are unassigned as margin. If those are not needed they could be opened for missions of opportunity.

From objects at the border of the solar system such as Ultima Thule, over ring systems and moons of gas giants to comets and asteroids in the vicinity of the earth, small solar system bodies show a large variety of shapes. Asteroids in particular underwent multiple collisions, subsequent re-aggregation, and further collisions, while grinding down in a collisional cascade large planetesimals to the population of asteroids we see today. Therefore, they are perfect laboratories to study formation processes of small solar system bodies.

For this purpose the scientific scope of the mission is to reconstruct the interior configuration of an asteroid to search for traces of this process and correlated numerical models.

The proposal combines three asteroid in-situ interior inversion methods based on: Ground penetrating radar, gravimetry and seismic sounding. The focus and novelty of the concept gives the mission the name: AI3.

In addition, optical and spectral measurements will deliver context science to help interpreting the data and yield boundary conditions.

The concept of AI3 is based on three CubeSats: Two identical 8U DISCUS CubeSats D1 and D2 and a 16U Small CubeSat-Carry-on Impactor (SCSCI) provided by JAXA, with heritage from Hayabusa2. The DISCUS CubeSats will carry a ground penetrating radar, a satellite-to-satellite radio tracking system, and a gravimeter, as well as an altimeter and a hyperspectral imager. The use of two identical CubeSats provides full redundancy, as the minimum science goals can be reached with one DISCUS, but mainly leverages the CubeSat approach to maximize the science outcome by taking bistatic/stereo measurements. It enables performing simultaneous observations at a higher risk acceptance to improve the scientific results. For the impact event D1 will descent to the surface. The design allows surviving for at least 20 hours on battery to record the Seismic waves induced by the impactor. At the same time, D2 will provide optical images of the impact at an unpresented cadence and resolution.


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