LICIACube Spacecraft

After traveling 16 months on DART, will be released in order to monitor all effects of the impact.

After traveling 16 months onboard the DART satellite, LICIACube, the Italian cubesat, will be release in order to monitor all effects of the impact: the crater and the evolution of the debris produced by the collision. All data acquired during this phase of the mission will be very important to verify the efficacy of the impact. It will be the first Italian mission destined for a target so far away. In order to deal with this unique mission, the Argotec platform will use an autonomous navigation system, an integrated propulsion system, a strong camera and an advanced on-board computer.

The LICIACube will fly by about 3 minutes after impact, recording details of the impact plume and surfaces at resolutions up to 2 meters per pixel. After impact, Earth-based observations will continue in order to characterize the resulting change in orbit of Dimorphos induced by the impact. The distance to Earth at impact will be approximately 11.2 million km. (The ESA Hera mission is planned to fly by Didymos in 2026 for followup observations.)

Released approximately 2 days before the DART impact. LICIACube will perform a separation maneuver to follow behind DART and return images of the impact, the ejecta plume, and the resultant crater as it flies by. It will also image the opposite hemisphere from the impact. LICIACube is 3-axis stabilized and has a propulsion capability of 56 m/s. The onboard imager has a 7.6 cm aperture, F/5.2 telescope, and an IFOV of 2.9 arcsec/pixel.

Challenges and Lessons:

• Performance of the propulsion system: Overall good. Only 2 orbital maneuvers to reach the target.
• Transponder: Overall really good accuracies. As good as any other large S/C.
  • Challenge: Residual Doppler bias potentially inducing errors in the solution.
  • Well characterized through the range data.
• Large non-gravitational accelerations.
  • We needed to change the strategy of the stochastics during the operations.
  • More desaturation maneuvers were required.
• Payload had some unexpected problems with the lenses.
  • Required severe postprocessing. Not good for NAV. OK for science.
• Given the platform limitations related to the COTS hardware employed, the navigation process is challenging when dealing with strong navigation requirements.
  • Not optimal systems, not redundant, they are cheaper.

[DART released LICIACube 360 hours before the impact on the asteroid, which was piggybacked during its travel. In this framework, the LICIACube spacecraft was able to obtain multiple images of the DART impact ejecta plume over a span of 15 minutes, being successful in its scientific objectives [1]:](https://digitalcommons.usu.edu/smallsat/2023/all2023/66/)

• testifying the DART impact;
• obtaining multiple (at least 3) images of the ejecta plume taken over a span of time and phase angle, that, with reasonable expectations concerning the ejecta mass and particle size distribution, could potentially:
• allow measurement of the motion of the slow (<5 m/s) ejecta: this requirement was intended as the possibility to acquire images at spatial scale better than 5 m/pixel, with the possibility to distinguish the movements of the slowest particles of the plume by the sequence of images.
• allow estimation of the structure of the plume, measuring the evolution of the dust distribution;
• obtaining multiple (at least 3) images of the DART impact site with a sufficient resolution to allow measurements of the size and morphology of the crater. These images were taken sufficiently late after the impact that the plume can be reasonably expected to have cleared;
• obtaining multiple (at least 3) images of Dimorphos showing the non-impact hemisphere, hence increasing the accuracy of the shape and volume determination.

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